HK1152741A - Illuminating device, display device and light guide plate - Google Patents

Description

Lighting device, display device and light guide plate

Technical Field

The present invention relates to a thin illumination device capable of area active driving, a display device using the illumination device, and a light guide plate used in the illumination device.

Background

In recent years, liquid crystal display devices that are rapidly and generally used in place of Cathode Ray Tubes (CRTs) have been widely used in liquid crystal televisions, monitors, cellular phones, and the like, taking advantage of their advantages such as energy saving, thin profile, and lightweight. As a method of utilizing these advantages, there is an improvement of an illumination device (so-called backlight) disposed behind a liquid crystal display device.

The lighting devices are mainly classified into a side light type (also referred to as an edge light type) and an immediate type. The edge light type has a structure in which a light guide plate is provided behind a liquid crystal display panel, and a light source is provided on an end face (lateral end) of the light guide plate. The light emitted from the light source is reflected by the light guide plate and indirectly and uniformly irradiated on the liquid crystal display panel. With this configuration, although the luminance is low, the thickness can be reduced, and an illumination device having excellent luminance uniformity can be realized. Therefore, the side-light type lighting device is mainly applied to small and medium-sized liquid crystal displays such as cellular phones and notebook computers.

On the other hand, the direct-type lighting device has a plurality of light sources arranged behind a liquid crystal display panel and directly irradiates the liquid crystal display panel with light. Therefore, the liquid crystal display device is mainly applied to a large liquid crystal display device of 20 inches or more, which is easy to obtain high brightness even with a large screen. However, the thickness of the conventional direct-type lighting device is about 20mm to 40mm, which hinders further thinning of the display.

In view of this, attempts have been made to reduce the thickness of a large-sized liquid crystal display by arranging a plurality of side-light type illumination devices (see, for example, patent documents 1 and 2).

The illumination devices (surface light source devices) described in patent documents 1 and 2 have a tandem type structure in which light guide plates, which are plate-shaped light guide blocks, are connected in the direction of primary light (longitudinal direction), and primary light sources for supplying the primary light to the respective light guide blocks are provided. In this way, a lighting device in which a plurality of light emitting units (light source units) each including a combination of a light source and a light guide plate are arranged is generally called a tandem lighting device.

Patent document 1: japanese laid-open patent publication No. 11-288611 (published: 10/19/1999) "

Patent document 2: japanese laid-open patent publication No. 2001-312916 (published: 11/9/2001) "

Disclosure of Invention

In such a tandem-type lighting device, in order to reduce light leakage to an adjacent region formed by the light guide blocks in tandem, the thickness of a connecting portion (light source arrangement portion) between the light guide blocks is made as thin as possible.

However, the thinner the thickness of the connecting portion between the light guide blocks is, the lower the strength of the combined body of the light guide blocks is.

The present inventors have made extensive studies and as a result, have found that the above-described problems can be solved by providing an illumination region for emitting light incident from a light source to the outside and a light guide region for guiding the light incident from the light source to the illumination region in a light guide plate, and providing a plurality of light emitting portions partitioned by slits, for example, in the illumination region.

The above-described illumination device has a structure equivalent to a structure in which the light guide block described in the related art is connected to the light guide portion in the lateral direction (i.e., in a direction intersecting the plurality of light guide portions), if the arrangement direction (serial direction) of the light source units is set to the longitudinal direction. Therefore, the strength of the bonded body of the light guide block can be maintained while reducing light leakage to the adjacent region.

In addition, according to the above method, it is preferable that a light guide plate having a structure in which a plurality of light guide blocks are connected in a lateral direction can be manufactured from one light guide plate. However, in order to increase the size of the light guide plate, when a light guide plate having a structure in which a large number of light guide blocks are integrated is manufactured, the light guide plate is easily warped and easily bent. Therefore, there is a limit to the size of one light guide plate. In addition, light emission is caused to be uneven in the plane.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an illumination device capable of reducing light leakage to an adjacent region and maintaining the strength of a combination of light guide blocks, and capable of emitting light uniformly, a display device using the illumination device, and a light guide plate applied to the illumination device.

In order to achieve the above object, an illumination device includes a plurality of light source units including a light guide plate and a plurality of light sources, wherein an illumination region for emitting light incident from the light sources to the outside and a light guide region for guiding the light incident from the light sources to the illumination region are arranged in the light guide plate, the illumination region is divided into a plurality of light emitting parts by providing a dividing part for limiting the transmission of the light in the optical axis direction of the light sources, at least one of the light sources is arranged in the light guide region with respect to each of the light emitting parts, the plurality of light source units are arranged at least in a first direction in which the light emitting parts are arranged in the illumination region, and the dividing part is also provided at least in a part between the light emitting parts between the light source units adjacent in the first direction.

In order to achieve the above object, a lighting device includes a plurality of light source blocks including a light source and a light guide block, the light guide block including a light emitting portion for emitting light incident from the light source to the outside and a light guide portion for guiding the light incident from the light source to the light emitting portion, the plurality of light source blocks being arranged in the first direction to form a light source unit, at least a part of adjacent light guide portions of the light source unit being connected to each other, and an optical dividing portion being provided at least at a part between adjacent light emitting portions, the plurality of light source units being arranged in at least the first direction, and the dividing portion being provided at least at a part between the light emitting portions between the light source units adjacent in the first direction.

Each of the lighting devices includes a plurality of light emitting units in a lighting area by the dividing unit, and a plurality of light emitting units are provided for one light guide plate. The light guide plate has a structure equivalent to a structure in which the plurality of light guide blocks are connected to the light guide portions in the lateral direction (direction intersecting the plurality of light guide portions) if the arrangement direction (serial direction) of the light source units is the longitudinal direction.

Further, by providing the dividing portions between the light emitting portions, light emitted from each light source can be confined to the intended light emitting portion with a simple configuration, and light leakage to the adjacent light emitting portions can be suppressed and avoided.

In addition, since the dividing portion is provided in at least a part of the light emitting portions between the light source units adjacent to each other in the first direction, even if the plurality of light source units are arranged in the first direction, the light emitting characteristics are the same in any part of the illumination region. Therefore, uniform light emission in the plane can be performed.

Thus, according to the above-described configurations, it is possible to provide an illumination device that can reduce light leakage to adjacent regions, maintain the strength of a combined body as a light guide block, and make light emission uniform in any part of an illumination region.

In order to achieve the above object, a light guide plate is provided with an illumination region for emitting light incident from a light source to the outside and a light guide region for guiding the light incident from the light source to the illumination region, wherein the illumination region is divided into a plurality of light emitting parts by providing a dividing part for restricting transmission of the light in the direction of an optical axis of the light source, and the dividing part is provided also in at least a part of at least one end in a first direction in which the light emitting parts of the illumination region are arranged.

In order to achieve the above object, a light guide plate includes a plurality of light guide blocks each including a light emitting portion for emitting light incident from a light source to the outside and a light guide portion for guiding the light incident from the light source to the light emitting portion, wherein the plurality of light guide blocks are arranged one-dimensionally, at least a part of adjacent light guide portions are connected to each other, an optical dividing portion is provided at least at a part between the adjacent light emitting portions, and the dividing portion is also provided at least a part of at least one end in the arrangement direction of the light guide blocks.

Thus, these light guide plates are suitable for the above-described illumination device.

In order to achieve the above object, a display device includes the above illumination device.

The illumination device can reduce light leakage to the adjacent area and maintain the strength of the combined body as the light guide block. Even if a plurality of light source units are arranged in the first direction, the light emission is the same in any part of the illumination region. Therefore, uniform light emission in the plane can be performed.

Thus, according to the above configuration, a display device which can realize sufficient luminance and excellent luminance uniformity, and which has a high intensity and a strong structure of the illumination device can be obtained.

Further, the display device can be made thin by having the above configuration. Further, even when the light emitting area is large, sufficient luminance and excellent luminance uniformity can be realized, and the luminance of each illumination region can be adjusted to meet the high image quality.

Drawings

Fig. 1 is a plan view showing a schematic configuration of a main part of an illumination device according to an embodiment of the present invention.

Fig. 2(a) is a plan view showing a schematic configuration of a light source unit according to an embodiment of the present invention; (b) is a cross-sectional view taken along line A-A of the light guide plate of the light source unit shown in (a).

Fig. 3 is a B-B line-view cross-sectional view of the light source unit shown in fig. 2 (a).

Fig. 4 is a plan view showing a schematic configuration of a main part of an illumination device using a light source unit in which a slit portion is not provided in an illumination region.

Fig. 5 is a plan view schematically showing a configuration of a light source unit according to an embodiment of the present invention, in which a light source in the light source unit is enlarged.

Fig. 6 is another plan view showing a schematic configuration of a light source unit according to an embodiment of the present invention, in which a light source in the light source unit is enlarged.

Fig. 7 is still another plan view showing a schematic configuration of a light source unit according to an embodiment of the present invention, in which a light source in the light source unit is enlarged.

Fig. 8 is a view showing another example of the shape of the light guide plate of the light source unit shown in fig. 2(a) in a cross-sectional view taken along line B-B of the light source unit shown in fig. 2 (a).

Fig. 9 is a view showing still another example of the shape of the light guide plate of the light source unit shown in fig. 2(a) in a cross-sectional view taken along line B-B of the light source unit shown in fig. 2 (a).

Fig. 10 is a perspective view showing the shape of the light guide plate shown in fig. 9 when the light guide plate is viewed from different angles.

Fig. 11 is a front view, a left side view, a plan view, and a right side view of the light guide plate shown in fig. 9.

Fig. 12(a) is a plan view showing a schematic configuration of a tandem-type lighting device in which the light source units shown in fig. 1 are partially overlapped in a staggered manner, and (b) is a cross-sectional view taken along line C-C of the lighting device shown in (a).

Fig. 13 is a block diagram showing an example of a configuration of a main part of the lighting device according to the embodiment of the present invention.

Fig. 14 is a plan view showing a schematic configuration of another light source unit according to an embodiment of the present invention.

Fig. 15(a) is a plan view showing a schematic configuration of a main part of a lighting device according to another embodiment of the present invention, and (b) is a cross-sectional view taken along line D-D of a light guide plate of the lighting device shown in (a).

Fig. 16(a) is a plan view showing a schematic configuration of a main part of an illumination device according to still another embodiment of the present invention, and (b) is a cross-sectional view taken along line E-E of a light guide plate of the illumination device shown in (a).

Fig. 17(a) is a plan view showing a schematic configuration of a main part of another illumination device according to still another embodiment of the present invention, and (b) is a cross-sectional view taken along line F-F of the light guide plate of the illumination device shown in (a).

Fig. 18 is a plan view showing a schematic configuration of a main part of a lighting device according to still another embodiment of the present invention.

Fig. 19(a) is a plan view showing a schematic configuration of a main part of another illumination device according to still another embodiment of the present invention, and (b) is a sectional view taken along line G-G of the light guide plate of the illumination device shown in (a).

Fig. 20(a) and (b) are plan views each showing an example of a schematic configuration of a main part of an illumination device according to still another embodiment of the present invention.

Fig. 21(a) is a plan view showing a schematic configuration of a main part of another illumination device according to still another embodiment of the present invention, and (b) is a sectional view taken along line H-H of the light guide plate of the illumination device shown in (a).

Fig. 22 is a cross-sectional view schematically showing a schematic configuration of a main part of a liquid crystal display device according to still another embodiment of the present invention.

Fig. 23(a) is a plan view showing an example of a schematic configuration of an illumination device provided in the liquid crystal display device shown in fig. 22, and (b) is an end view schematically showing the schematic configuration of the liquid crystal display device shown in fig. 22 when the liquid crystal display device is viewed from the side opposite to the light source in the illumination device shown in fig. 23 (a).

Fig. 24 is a plan view showing an operation principle of the area active driving of the liquid crystal display device.

Fig. 25 is a block diagram showing a schematic configuration of a main part of a liquid crystal display device according to still another embodiment of the present invention.

Fig. 26 is a block diagram showing a schematic configuration of a liquid crystal display device for a television receiver according to another embodiment of the present invention.

Fig. 27 is a block diagram showing a relationship between a tuner section and a liquid crystal display device of the television receiver shown in fig. 26.

Fig. 28 is an exploded perspective view of the television receiver shown in fig. 26.

Reference numerals

1 light guide plate

1A light guide block

2 incident light end face

3 light guiding region

3A light guide part

4 illumination area

5 light emitting surface

6 structure

7 dead zone (dead area)

8 slit part (divided part)

8A cut part (divided part)

9 light emitting part

11 step part

12 front end face

13 groove part (divided part)

13A groove part (divided part)

14 Scattering component (dividing part)

14A Scattering Member (divided part)

16 Low refractive index layer (divided part)

16A Low refractive index layer (divided part)

20 light source unit

20A light source block

21 light source

22LED chip

23LED chip

24LED chip

30 Lighting device

31 light-shielding body (light-shielding component)

34 lighting control circuit

40 liquid crystal display device

41 LCD panel (display panel)

42 substrate

43 optical sheet

44 maximum gray scale level detection circuit

45 gray scale conversion circuit

50Y/C separation circuit

51 video chroma circuit

52A/D converter

53 liquid crystal controller

54 backlight source driving circuit

55 micro-computer

56 gray scale circuit

60 tuning part

61 first frame

61a opening part

62 second frame body

63 Circuit for operation

64 support member

BL light source

BLU light source unit

L-shaped lighting device

LA luminous surface

LG light guide plate

Detailed Description

(embodiment mode 1)

An embodiment of the present invention will be described below with reference to fig. 1 to 14.

Fig. 1 is a plan view showing a schematic configuration of a main part of the lighting device of the present embodiment.

As shown in fig. 1, the illumination device L of the present embodiment includes a plurality of light source units 20, and the light source units 20 include a light guide plate 1 (light guide) and a plurality of light sources 21. The illumination device L has a structure in which the light guide plates 1 of the light source units 20 are arranged on the same plane so as to overlap each other.

First, the structure of the light source unit 20 of the present embodiment will be described below.

Fig. 2(a) is a plan view showing a schematic configuration of the light source unit 20 of the present embodiment, and fig. 2(b) is a sectional view taken along line a-a of the light guide plate 1 of the light source unit 20 shown in fig. 2 (a). Fig. 3 is a cross-sectional view taken along line B-B of the light source unit 20 shown in fig. 2 (a).

As shown in fig. 2a, the light source unit 20 includes a light guide plate 1 (light guide) and a plurality of light sources 21 (point light sources) provided on one end surface of the light guide plate 1.

The light source unit 20 is a side-light type light source unit (surface light source unit) provided with a light source 21 and emitting (surface radiating) light incident from one end surface of the light guide plate 1 from one main surface (disk surface).

In the following description, for convenience of explanation, a principal surface on the light emitting side of the light guide plate 1 is referred to as an upper surface or a front surface, and a principal surface on the opposite side is referred to as a lower surface or a rear surface.

As shown in fig. 2a and 3, the light guide plate 1 bends (reflects) light entering from a light entrance end face 2 (light entrance end face) which is an end face on the light source 21 side inside the light guide plate 1, and emits the light from a part of the upper surface of the light guide plate 1.

The light guide plate 1 is made of, for example, a methacrylic resin such as PMMA (methyl methacrylate resin), or a transparent resin such as COP (cycloolefin polymer) such as "ZEONOR" (registered trademark, manufactured by Zeon corporation, japan), COC (cycloolefin copolymer), or polycarbonate. However, the material of the light guide plate 1 is not limited to the above examples, and any material generally used for light guide plates can be used, and the material is not limited to the above examples, and for example, any transparent resin can be applied without particular limitation.

When the central axis direction of light emitted (radiated) from the light source 21 is taken as the optical axis direction, the light guide plate 1 has two regions having different functions in the optical axis direction. In the present embodiment, the optical axis direction of the light emitted from the light source 21 is a direction perpendicular to the light emitting surface of the light source 21, that is, a direction perpendicular to the light entrance end surface 2. Thus, the light guide plate 1 has the two regions along the main surface.

As shown in fig. 2(a) and 3, the light guide plate 1 includes a light guide region 3 and an illumination region 4 in this order from the light entrance end face 2 side in a plan view. Thus, the light guide plate 1 emits light to the outside from a part of one main surface, not the entire surface of one main surface of the light guide plate 1. In the present embodiment, "in a plan view" has the same meaning as "when the light guide plate 1 is viewed from directly above (in a direction perpendicular to the main surface)".

The light guide region 3 has a light entrance end surface 2 as a light receiving surface, and guides light entering from the light entrance end surface 2 to the illumination region 4 along the main surface.

On the other hand, the illumination region 4 includes a light-emitting surface 5 on the upper surface thereof, and the light-emitting surface 5 is disposed to face the surface to be irradiated of the irradiation target object, and emits light to the outside (the surface to be irradiated of the irradiation target object). The illumination region 4 emits light guided from the light guide region 3 from the light emitting surface 5.

In addition, when a point-like light source is used as the light source 21 as described above, the light emitted from the light source 21 is emitted at a certain angle, and thus the emission angle is limited. Therefore, as shown in fig. 2(a), in the vicinity of the light source 21, there is a portion (hereinafter referred to as "dead zone") 7 where light cannot be conducted (irradiated) due to the directivity of the light source 21 and becomes dark and shaded.

In this embodiment, a region including the dead zone 7 is used as the light guide region 3. In this way, without using the dead zone 7 as the illumination region 4, the light emitted from the light source 21 is diffused sufficiently in the light guiding region 3 and then radiated from the light emitting surface 5, and thus the light source unit 20 capable of improving the luminance uniformity and having no dark place on the light emitting surface 5 can be provided.

The light guide region 3 also functions as a color mixing section (light mixing section) for mixing color (light mixing) of light emitted from the light source 21. In this way, white illumination can be obtained by mixing light emitted from the individual single-color LEDs (light emitting diodes) of different emission colors, for example, R (red), G (green), and B (blue).

As shown in fig. 3, the light guide region 3 and the illumination region 4 are integrally provided. However, a region corresponding to the illumination region 4 on the back surface of the light guide plate 1 is processed or treated to emit the light guided from the light guide region 3 to the outside of the light guide plate 1 from the light emitting surface 5, such as a structure 6 (light scattering member) shown in fig. 3. In the present embodiment, the structure 6 is provided on the rear surface of the light guide plate 1, but the present embodiment is not limited thereto. The structure 6 may be provided on at least one of the front and rear surfaces (the light-emitting surface 5 and the opposite surface) of the light guide plate 1 as long as it is provided in the illumination region 4, or may be provided inside the light guide plate 1.

On the other hand, the light guide region 3 is not subjected to the above-described processing or treatment, and the light entering the light guide region 3 from the light entrance end face 2 is reflected at an interface with the outside of the light guide region 3, for example, and guided to the illumination region 4.

Therefore, light incident on the light guide plate 1 from the light source 21 reaches the illumination region 4 via the light guide region 3, is scattered and reflected in the illumination region 4, and is emitted from the light emitting surface 5 to the outside of the light guide plate 1.

Examples of the processing or treatment performed on the illumination region 4 include prism processing, texturing, and printing. However, the present embodiment is not limited to this. As the processing or treatment, known processing or treatment conventionally performed on the light guide plate to emit light from the light guide plate can be suitably employed.

Thus, the structure 6 formed in the illumination region 4 of the light guide plate 1 by the above-described processing or treatment may be, for example, a structure having a fine uneven shape (grain shape) or a prism shape by grain processing, or may be a dot pattern formed by printing or the like. The structure 6 is not limited to the above example, and all structures (light diffusion members) having a light diffusion function of emitting light in the light guide plate 1 to the outside of the light guide plate 1 have been used in the related art.

The density of the structures 6 may be constant, or may be different depending on the distance from the light source 21 or the amount of light emitted from the light emitting surface 5 of the light guide plate 1. For example, by increasing the density or the area of the structure 6 as the distance from the light source 21 increases, the luminance in the light emitting surface 5 can be made uniform.

On the other hand, by not performing the above-described processing or treatment on light guide region 3, light emitted from light source 21 is reflected at the interface between light guide region 3 and the outside, and is guided to illumination region 4 without being substantially emitted from light guide region 3 to the outside. However, for example, in order to suppress light leakage more reliably and to suppress light attenuation by reusing light reflected by the interface more effectively, a light shielding sheet such as a reflection sheet may be provided on the front and back surfaces of the light guiding region 3 so as to cover the light guiding region 3, or mirror processing may be performed.

However, in the present embodiment, the light-emitting surface 5 of the light guide plate 1 is disposed to face the surface to be irradiated of the object to be irradiated. Thus, in the case of the lighting device L of the present embodiment, which is a so-called tiled (tile) type lighting device in which the plurality of light guide plates 1 are arranged only on the same plane without being overlapped with each other (hereinafter, simply referred to as "overlapped with each other"), the light guide region 3 and the light source 21 are covered with the light blocking member. As the light shielding member, for example, a frame of a liquid crystal display device or the like is used, and a part of the electronic components of the lighting device L is provided.

From the viewpoint of suppressing the attenuation of light, it is desirable that the light emitted from the light source 21 is guided to the illumination region 4 without being emitted from the light guide region 3 to the outside. However, when the illumination device L is a tiled illumination device, for the above reasons, if light can be guided to the illumination region 4, there is no problem even if there is light leakage. Thus, when the illumination device L is a tiled illumination device, it is not necessary to provide a light-shielding sheet such as a reflector or to perform mirror processing.

Next, the structure of the illumination region 4 will be described below.

As shown in fig. 2(a) and (b), the light guide plate 1 of the present embodiment has a structure in which the illumination region 4 is divided into a plurality of regions (hereinafter referred to as "light emitting portions") 9 by having a dividing portion for limiting the transmission of light. The dividing portion is provided along the optical axis direction of the light emitted from the light source 21.

That is, as shown in fig. 2(a), the light guide plate 1 has the following structure: the plurality of light guide blocks 1A, which are known in the art, are arranged one-dimensionally, and have light guide regions 3 connecting adjacent light guide portions 3A of the light guide blocks 1A, and optical dividing portions are provided between adjacent light emitting portions 9. Further, the light source unit 20 has a structure in which a plurality of light source blocks 20A are connected at the light guide portion 3A as described above, and the light source block 20A includes the light guide block 1A and the light source 21 described above.

In the present embodiment, the illumination region 4 of the light guide plate 1 is provided with a slit portion 8 (slit) penetrating the front and rear surfaces of the light guide plate 1 as the above-described dividing portion. The slit portion 8 is provided from one end to the other end of the illumination region 4 (i.e., from a boundary portion with the light guide region 3 to the end face opposite to the light entrance end face 2, i.e., the distal end face 12) in parallel with the optical axis direction of the light emitted from the light source 21. Thereby, the illumination region 4 has a plurality of light emitting portions 9 divided in a direction perpendicular to the light entrance end face 2. The light guide plate 1 has a structure in which a plurality of light emitting units 9 are arranged in a comb-like manner with respect to the light guide region 3 in a plan view.

Therefore, the light guide plate 1 has the following structure: when the arrangement direction (the serial direction, the second direction) of the light source units 20 is set to the vertical direction, the plurality of light guide blocks 1A are configured such that the light guide portions 3A are connected in the horizontal direction (the direction intersecting the plurality of light guide portions 3A, the first direction).

In the light guide plate 1, the light guide portions 3A of the adjacent light guide blocks 1A are integrally provided by providing the divided portions in the illumination region 4, and the connecting portions of the light guide portions 3A have high strength, and thus have a strong structure as a combined body of the light guide blocks 1A. Therefore, in the illumination device 30 in which the plurality of light source units 20 are arranged so that at least a part of the light guide region 3 of each light guide plate 1 overlaps, the light guide region 3 has high strength, and even if the thickness of the light guide region 3 of each light guide plate 1 is small, the light guide block 1A has a firm structure as a combined body.

In addition, in the illumination device 30, by providing the divided portions in the illumination region 4, it is possible to close the light emitted from each light source 21 in each of the light emitting portions 9 as a destination and to suppress or avoid leakage to the adjacent light emitting portions 9 with a simple configuration.

Thus, according to the present embodiment, the illumination device 30 capable of reducing light leakage to the adjacent region and maintaining the strength of the joined body as the light guide block 1A can be provided.

In fig. 2(a) and (b), the illumination region 4 is divided into 6 regions, but the number of the slit portions 8 is not limited as long as the illumination region 4 can be divided into regions. That is, the number of regions is not particularly limited as long as the illumination region 4 is divided into two or more regions by providing at least one slit portion 8. The size of each light-emitting portion 9 defined by the slit portion 8 is not particularly limited. The size of each light emitting unit 9 is not particularly limited, and may be appropriately set according to the size of the surface to be irradiated of the irradiation target.

However, when the illumination device L is used as an illumination device for a display device such as a liquid crystal display device, the size of each light emitting section 9 is preferably equal to an integral multiple of one pixel. This enables brightness control for each pixel unit or each pixel column.

The light sources 21 provided on the end surface of the light guide plate 1 are provided one for one with respect to each light emitting portion 9 so as to correspond to each light emitting portion 9 divided by the slit portion 8. Thus, light emitted from each light source 21 provided on the end surface of the light guide plate 1 is guided to each light emitting section 9 partitioned by the slit section 8.

By forming the slit portion 8 in the illumination region 4, reflection by the slit portion 8 is generated. All light reaching the slit portion 8 at an angle satisfying the total reflection angle condition is reflected. The angle satisfying the total reflection angle condition is an angle exceeding a critical angle θ that is a minimum incident angle for total reflection. A part of the light that does not satisfy the total reflection angle condition leaks to the adjacent light emitting portion 9, but if the slit portion 8 is not provided, all the light incident on the region corresponding to the slit portion 8 transmits through the region. Therefore, by providing the slit portion 8, the emission region of the light emitted from each light source 21 can be limited. Thus, according to the present embodiment, the amount of light emitted from each light-emitting portion 9 can be independently adjusted by independently adjusting (independently driving) the amount of light of the light source 21 corresponding to each light-emitting portion 9. Therefore, the illumination luminance can be adjusted for each light emitting unit 9. Further, since the illumination region 4 is completely divided by the slit portion 8, there is an advantage that the contrast between the adjacent light emitting portions 9 is high.

Further, by providing the slit portions 8 in the light guide plate 1, the number of components can be reduced as compared with the case where the light guide blocks 1A having the same number as the light emitting portions 9 are arranged in the lateral direction. Further, one light guide plate can be formed by a plurality of light emitting portions 9, and thus productivity can be improved. In addition, since the number of connections of the light guide plate 1 can be reduced, the arrangement can be facilitated, and the time and cost required for the connections can be reduced.

Further, by providing the slit portion 8 in the light guide plate 1, it is preferable that a light guide plate having a structure in which the light emitting portions 9 are connected in any region in the lateral direction (in other words, a structure in which the plurality of light guide blocks 1A are connected in the lateral direction) can be manufactured from one light guide plate.

However, in order to increase the size of the light guide plate 1, when the light guide plate 1 having a structure in which the excessive light guide blocks 1A are integrated is manufactured, the light guide plate 1 is easily warped and easily bent. Therefore, there is a limit to the size of one light guide plate, and there is a limit to the number of light emitting portions 9 that can be connected in the lateral direction.

Therefore, for example, when the light guide plate 1 has the shape shown in fig. 4, if the light guide plate 1 is increased in size by arranging a plurality of light guide plates 1 in the lateral direction as shown in fig. 4, the slit portion 8 is not present between the light emitting portions 9, 9 between the adjacent light guide plates 1, and the light emission in the plane becomes uneven due to the size of the slit portion 8.

Therefore, in the present embodiment, as shown in fig. 1, notches 8A (notches) of 1/2 width of the slit portion 8 are provided at both ends of the light guide plate 1 in the arrangement direction of the light emitting portions 9 so as to face the slit portion 8 in the illumination region 4.

In the case where the cutout portions 8A are provided at both ends in the lateral direction of the light guide plate 1 as described above, when a plurality of light source units 20 are arranged in parallel so that the light emitting portions 9 of the other light source unit 20 are arranged in the direction in which the light emitting portions 9 of the adjacent one of the light source units 20 are arranged as shown in fig. 1, the slit portions 8 similar to the slit portions 8 provided in the respective light guide plates 1 are formed between the light emitting portions 9, 9 between the adjacent light guide plates 1, 1 by the cutout portions 8A provided in the adjacent light guide plates 1.

In the example shown in fig. 1 and fig. 2(a) and (b), when the light guide plate 1 is divided into a plurality of light guide blocks at the central portion of the slit portion 8, all the light guide blocks have the same shape. That is, when the illumination region 4 is divided into a plurality of regions at the center of the divided portions, the light guide plates 1 have the same shape for each region (that is, each region including the light emitting portion 9 and the two divided portions on both sides thereof).

Therefore, the spread of light emitted from these regions in each light source unit 20 is the same in any region. Therefore, according to the present embodiment, even if a plurality of light source units 20 are arranged in the lateral direction, the light emission is the same in any region, and therefore, uniform light emission in the plane can be performed. This makes it possible to provide an illumination device that can reduce light leakage to adjacent regions, maintain the strength of the joined body as a light guide block, and make the light emission of each light emitting section 9 uniform.

The light guide plate 1 can be formed by injection molding, extrusion molding, hot press molding, cutting, or the like. However, the method of forming the light guide plate 1 is not limited to these molding methods, and any processing method can be applied as long as the same characteristics can be obtained.

The method of forming the slit portion 8 and the notch portion 8A is not particularly limited. The slit portion 8 and the cutout portion 8A may be formed simultaneously with the formation of the light guide plate 1 by using a mold, for example, or may be formed after the light guide plate 1 without slits or cutouts is formed and thereafter by using a cutting device (cutting device).

The cutting device is not particularly limited, and various cutting devices such as a diamond cutter, a wire cutter, a water jet cutter, a blade, and a laser can be used. After the light guide plate 1 having no slits or cutouts is formed in this manner, when the slits or cutouts are formed in the light guide plate 1 by using a cutting device, a plurality of light guide plates 1 having no slits may be stacked, and the slits or cutouts may be collectively formed in the stacked light guide plates 1.

In the present embodiment, the width of the slit portion 8 is not particularly limited. However, light is not actually emitted from the slit portion 8 and the notch portion 8A. Therefore, the smaller the width of the slit portion 8 and the cutout portion 8A is, the more preferable. The width of the slit portion 8 is preferably set to 1mm or less. If the width of the slit portion 8 is b and the width of the cutout portion 8A is c, the width c of the cutout portion 8A is preferably 1/2b as described above.

However, the present embodiment is not limited to this, and when a plurality of light source units 20 are arranged in parallel such that the light emitting portions 9 of one light source unit 20 adjacent to each other are aligned in the direction in which the light emitting portions 9 of the other light source unit 20 are aligned as shown in fig. 1, each cutout portion 8A may be provided between the light emitting portions 9, 9 between the light source units 20, 20 arranged in parallel such that a slit portion similar to the slit portion 8 is formed by the cutout portions 8A, 8A provided in the adjacent light source units 20.

For example, the cutout portion 8A of one of the adjacent light source units 20 may have a width of 1/3, which is the width of the slit portion 8, and the cutout portion 8A of the other light source unit 20 may have a width of 2/3, which is the width of the slit portion 8. When the widths of the adjacent notch portions 8A, 8A are c1, c2, respectively, the following expression (1) may be satisfied.

c1+c2＝b ……(1)

In this case, each cutout portion 8A may be formed so as to satisfy formula (1), or adjacent light source units 20 may be combined so as to satisfy formula (1).

Further, the cutout portions 8A and 8A of the same light guide plate 1 may have the same width or may be different from each other.

However, each light guide plate 1 of the adjacent light source units 20 is preferably formed such that the cutout portions 8A on the same side have the same width, and the width obtained by adding the widths of the cutout portions 8A at both ends is equal to the width of the slit portion 8. Accordingly, when the plurality of light source units 20 shown in fig. 1 are arranged side by side in the same direction so that the light guide regions 3 are adjacent to each other and the illumination regions 4 are adjacent to each other, an illumination device satisfying the formula (1) can be easily obtained, which is preferable.

For example, if the light guide plates 1 are arranged so that the light emitting parts 9 are arranged in parallel on the left and right, the cutout 8A having a width of c1 is formed at the right end of the illumination region 4 of each light guide plate 1, and the cutout 8A having a width of c2 is formed at the left end of the illumination region 4 of each light guide plate 1. Therefore, when the plurality of light source units 20 are arranged in the same direction, for example, on a straight line as shown in fig. 1, the width of the slit portion formed between the light emitting portions 9 and 9 between the light source units 20 and 20 arranged side by side is inevitably b described above.

If the width of the cutout portion 8A is c1 ═ c2 ═ 1/2b, it is more preferable to arrange the light source units 20 so that the light emitting portions 9 of the other light source unit 20 are aligned in the direction in which the light emitting portions 9 of the one light source unit 20 are aligned, since the lighting device satisfying the formula (1) can be easily obtained.

In the present embodiment, a description has been given mainly taking as an example a configuration in which the plurality of light source units 20 are arranged in parallel in the same direction so that the light guide regions 3 are adjacent to each other and the illumination regions 4 are adjacent to each other. However, the present embodiment is not limited to this, and the light emitting portions 9 of the other light source unit 20 may be arranged in parallel so as to be aligned in the direction in which the light emitting portions 9 of the one light source unit 20 are aligned, and the directions thereof are not necessarily the same. Further, it is not necessarily arranged in a straight line.

The length of the light guide region 3 in the optical axis direction of the light emitted from the light source 21 is preferably set to be equal to or greater than the length of the dead zone 7 in the optical axis direction of the light emitted from the light source 21.

However, the longer the length of the light guide region 3 is, the larger the light guide plate 1 is (the larger the area is). Further, depending on the length of the light guide region 3, light emitted from the light source 21 to the light emitting portion 9 of the light guide block 1A identical to the light source 21 may be partially incident on the adjacent light emitting portion 9 by being diffused in the light guide region 3. Therefore, depending on the length of the light guiding region 3, the arrangement of the structures 6, the density calculation, or the luminance control for each light emitting section 9 may become complicated.

Accordingly, it is preferable that the slit portion 8 be provided in a region where irradiation regions of the adjacent light sources 21 overlap each other in each light source unit 20. Similarly, it is preferable that a slit portion formed by the cut-out portion 8A and the light guide plate 1 of the adjacent light source unit 20, or a slit portion 8 formed by the adjacent cut-out portions 8A, 8A is provided in a region where the irradiation regions of the light sources 21 overlap at the boundary portion of the light source units 20 arranged side by side. It is preferable that a region up to the overlap of the light emitted from the adjacent light sources 21 (irradiation regions of the adjacent light sources 21 with each other) be used as the light guiding region 3.

Accordingly, the length of the light guide region 3 is preferably set as appropriate so as to satisfy the above conditions, based on the radiation angle of the light emitted from the light source 21, the refractive index of the material of the light guide plate 1, the distance from the center of any one of the light sources 21 to the center of the adjacent light source 21, and the width of the light emitting part 9.

For example, when the refractive index of the transparent resin constituting the light guide plate 1 is in the range of 1.4 to 1.6 and the irradiation angle of light from the light source 21 is 42 to 45 degrees, the length of the light guide region 3 is preferably set so that the light guide region 3 is a region where irradiation regions of light emitted from adjacent light sources 21 at the irradiation angle overlap.

That is, if the length in the optical axis direction of the light emitted from the light source 21 with the light entrance end face 2 as a starting point is defined as the length in the optical axis direction, the length in the optical axis direction of the light guide region 3 is preferably equal to or longer than the length in the optical axis direction of the dead region 7 of the light source 21 and equal to or shorter than the length in the optical axis direction of a point where irradiation regions from the light entrance end face 2 to the adjacent light source 21 intersect with each other. In other words, the length of light guide region 3 is preferably such that the size of the cross section of the light beam emitted from light source 21 and radially diffused in light emitting portion 9 is equal to or larger than the size of the boundary between light guide region 3 and illumination region 4.

The length in the optical axis direction from the light entrance end surface 2 to the slit portion 8 and the cutout portion 8A is preferably equal to or less than the length in the optical axis direction from the light entrance end surface 2 to the point where the illumination regions of the adjacent light sources 21 intersect with each other.

Next, the light source 21 will be described with reference to fig. 5 to 7.

Fig. 5 to 7 are plan views each showing a schematic configuration of the light source unit 20 of the present embodiment in an enlarged manner of the light source 21 of the light source unit 20.

The light sources 21 are point light sources such as side-emission LEDs, for example, and the light sources 21 are arranged in a row on the light entrance end surface 2 of the light guide plate 1. The light sources 21 are provided one for one with respect to each of the light emitting portions 9 in the illumination region 4 of the light guide plate 1.

In this case, the center position of each light source 21 is preferably arranged on an extension line of the central axis of each light emitting unit 9. This allows the light emitted from the light source 21 to reach the destination light-emitting portion 9 without being incident on the light-emitting portion 9 adjacent to the destination light-emitting portion 9.

Further, the light source 21 and the light guide plate 1 are preferably disposed as close as possible. By disposing the light source 21 and the light guide plate 1 in close proximity to each other or in contact with each other, the light entrance efficiency from the light source 21 to the light guide plate 1 can be improved.

As shown in fig. 5, the light source unit 20 having a wide color reproduction range can be obtained by using a side-emission LED in which R, G, B of LED chips 22, 23, and 24 of respective colors are molded into one package as the light source 21.

However, the present embodiment is not limited to this. As the light source 21, as shown in fig. 6, R, G, B LED chips 22, 23, and 24 may be used in combination, each of which is molded in a different package.

When the LED chips 22, 23, and 24 of the respective colors are used in combination, it is necessary to sufficiently diffuse the light of the respective colors in order to obtain white light by mixing the LED chips 22, 23, and 24 of the respective colors.

According to the present embodiment, as described above, the light guide region 3 is provided between the light source 21 and the illumination region 4, thereby making it possible to sufficiently mix (mix) the light of each color. This makes it possible to obtain uniform white light. The light intensities and arrangement order of the LED chips 22, 23, and 24 are not particularly limited.

As the light source 21, as shown in fig. 7, an LED (white light emitting element) that emits white light from one LED chip may be used. Examples of the white light emitting element include a white light emitting element obtained by combining a blue LED and a yellow light emitting phosphor, but are not limited thereto.

In the present embodiment, as shown in fig. 3, a case where a plate-shaped light guide plate having a (substantially) uniform thickness in the light guide region 3 and the illumination region 4 is mainly used as the light guide plate 1 has been described as an example. However, the shape of the light guide plate 1 is not limited thereto.

Fig. 8 is a view showing another example of the shape of the light guide plate 1 of the light source unit 20 shown in fig. 2(a) in a cross-sectional view taken along line B-B of the light source unit 20 shown in fig. 2 (a).

The light guide plate 1 of the light source unit 20 shown in fig. 8 has the following shape: the light guide region 3 and the illumination region 4 are both flat and have no step, and the thickness (width of the light guide plate 1 in the direction perpendicular to the light emitting surface 5) becomes smaller as the distance from the light source 21 becomes larger.

That is, the light guide plate 1 shown in fig. 8 has a so-called wedge shape in which the back surface is inclined with respect to the front surface and the cross section along the optical axis direction of the light emitted from the light source 21 is tapered.

As described above, by forming the light guide plate 1 such that the thickness of the light guide plate 1 (particularly, the thickness of the light guide plate 1 in the illumination region 4) becomes smaller as the distance from the light source 21 becomes larger, the ratio (probability) of light scattered and reflected by the structure 6 can be increased as the distance from the light source 21 becomes larger.

Therefore, according to the light guide plate 1 shown in fig. 8, even if the amount of light reaching from the light source 21 becomes smaller as the distance from the light source 21 becomes larger, light emission with an intensity equivalent to that of a relatively close region can be obtained in a region of the illumination region 4 relatively distant from the light source 21. This can achieve further uniformity of luminance.

Since the rear surface of the light guide plate 1 is inclined with respect to the front surface, the structures 6 provided on the rear surface of the illumination region 4 are positioned on the optical path of the light emitted from the light source 21, and the light entering the illumination region 4 through the light guide region 3 can be efficiently scattered and reflected by the structures 6.

The thickness of the light guide plate 1 is not particularly limited, but is set to be, for example, about 1 to 2mm for the portion having the largest thickness and 0.6 to 1.2mm for the portion having the smallest thickness.

Fig. 9 is a view showing still another example of the shape of the light guide plate 1 of the light source unit 20 shown in fig. 2(a) in a cross-sectional view taken along line B-B of the light source unit 20 shown in fig. 2 (a). Fig. 10 is a perspective view showing the shape of the light guide plate 1 shown in fig. 9 when the light guide plate 1 is viewed from different angles, and fig. 11 is a front view, a left side view, a plan view, and a right side view of the light guide plate 1 shown in fig. 9.

The light guide plate 1 shown in fig. 9 to 11 is preferably formed such that the thickness of the light guide plate 1 in the illumination region 4 becomes smaller as the distance from the light source 21 becomes larger, as in the light guide plate 1 shown in fig. 8. Therefore, the light guide plate 1 shown in fig. 9 to 11 can obtain light emission with the same intensity as that of a relatively close region in the region relatively distant from the light source 21 in the illumination region 4. This can further uniformize the luminance.

The light emitting surface 5 of the light guide plate 1 shown in fig. 9 to 11 is horizontal, a step portion 11 is provided between the light guiding region 3 and the illumination region 4, and the illumination region 4 protrudes from the light guiding region 3 toward the light emitting surface 5. Therefore, the light guide plate 1 divides the light guide region 3 and the illumination region 4 with the step portion 11 as a boundary.

On the other hand, the back surface of the light guide region 3 and the back surface of the illumination region 4 are formed as a single plane. This allows light emitted from the light source 21 to be transmitted to the illumination region 4 without being undesirably bent, without hindering the linearity (linear forward movement) of the light.

In the light guide plate 1 shown in fig. 9 to 11, as in the light guide plate 1 shown in fig. 8, the back surface of the light guide plate 1 is inclined with respect to the light emitting surface 5 of the illumination region 4, and the structure 6 provided on the back surface of the illumination region 4 is positioned on the optical path of the light emitted from the light source 21. Thus, light incident on the illumination region 4 via the light guide region 3 can be efficiently scattered and reflected by the structure 6.

The light guide plates 1 shown in fig. 9 to 11 have the above-described shape (in particular, the light guide plates 1 in the illumination region 4 are formed such that the thickness thereof becomes smaller as the distance from the light source 21 becomes larger, and a step portion 11 is provided between the light guide region 3 and the illumination region 4), and a plurality of the light guide plates 1 can be alternately stacked so that the light emitting surfaces 5 of the light guide plates 1 are positioned on the same plane. However, the present embodiment is not limited to this, and the light guide plates 1 shown in fig. 3 and 8 can also be used in tandem.

Fig. 12(a) is a plan view showing a schematic configuration of a tandem-type illumination device in which the light source units 20 shown in fig. 1 are partially overlapped in a staggered manner, and fig. 12(b) is a cross-sectional view taken along line C-C of the illumination device shown in fig. 12 (a).

The illumination device 30 (illumination device L) shown in fig. 12(a) and (b) has a structure in which a plurality of light source unit 20 groups partially overlapping in a staggered manner in the optical axis direction are further arranged in parallel in a direction perpendicular to the optical axis direction.

As shown in fig. 12(a) and (b), when the light guide plates 1 shown in fig. 9 to 11 are formed as the lighting devices L of the present embodiment as the tandem type lighting device 30, as shown in fig. 12(b), the lighting devices 30 can be overlapped in a staggered manner without increasing the thickness thereof, and only the lighting regions 4 of the light guide plates 1 can be arranged to face the surface to be irradiated of the object to be irradiated.

Further, if the light guide plates 1 shown in fig. 9 to 11 are used, the illumination device 30 can be easily assembled by bringing the front end surface 12 of each light guide plate 1 into contact with the step portion 11 as shown in fig. 12 (b).

As shown in fig. 1, the stepped portions 11 are not necessary when the light guide plates 1 are used in a state of being arranged only on the same plane, and are not necessarily provided. However, even in such a case, by providing the step portion 11 between the light guide region 3 and the illumination region 4 as shown in fig. 9 to 11, positioning when the illumination region 4 is arranged to face the surface to be irradiated of the object to be irradiated and positioning of the light source 21 can be easily performed.

The size of the stepped portion 11, the thickness of the distal end surface 12, and the inclination angle of the upper surface of the light guide region 3 are not particularly limited as long as the light emitting surfaces 5 of the two light guide plates 1 are flush with each other when the light guide plate 1 is placed on the adjacent light guide plate 1 such that the distal end surface 12 of the light guide plate 1 abuts against the stepped portion 11 of the adjacent light guide plate 1.

However, from the viewpoint of controlling the scattering direction of light, the height of the stepped portion 11 is preferably as small as possible as long as an intensity that is not problematic in actual use can be obtained at an end portion (hereinafter referred to as "distal end portion") of the illumination region 4 on the side opposite to the light guide region 3. The height of the step portion 11 can be, for example, 0.6 mm. However, these numerical values are merely examples, and the present embodiment is not limited thereto.

The light guide plate 1 may have a shape and size such that the stepped portion 11 is provided in the light guide region 3 of the light guide plate 1 shown in fig. 8, for example.

In the illumination device 30 shown in fig. 12(a) and (b), two light source units 20 are arranged in parallel in a direction perpendicular to the optical axis direction of the light emitted from the light source 21 in a configuration in which 5 light source units 20 are overlapped in the optical axis direction. However, in the case where a plurality of light source units 20 are stacked in this way, the number of stacked light source units 20 may be 2 or more, and the number of parallel light source units 20 may also be 2 or more.

Thus, the number of regions in the optical axis direction of the light emitted from the light source 21 can be increased by partially overlapping the light source units 20 in the N-1 st, N-th, and … … (N.gtoreq.2). As a result, the number of light emitting units 9 can be increased two-dimensionally. Therefore, regardless of the size of one light guide plate 1, a continuously wide light emitting region can be realized as the light emitting surface LA of the lighting device 30.

In addition, when the light emitting area is increased, if the size is more than a certain level, the arrangement of a plurality of short light guide plates 1 is simpler in structure and can improve the strength, compared with the case where one light guide plate 1 is made longer.

In the case where the light source units 20 are partially overlapped in a staggered manner as described above, as shown in fig. 12(b), if the light source unit 20 in the k-th stage (k 1, … …, N-1, where N ≧ 2) is the light source unit BLU (k), the light guide plate 1 and the light source 21 (primary light source) of the light source unit BLU (k) are the light guide plate LG (k) and the light source BL (k), respectively, it is preferable that the light source BL (k +1) of the (k +1) th stage for supplying the primary light to the light guide plate LG (k +1) of the light source unit BLU (k +1) of the (k +1) th stage is disposed on the back side (inner side) of the light guide plate LG (k) of the light source unit BLU (k) of the (k +1) th stage (k 1, … …, N-1), between the light guide plate lg (k) and the light source BL (k +1), a light blocking member 31 (light blocking member) for blocking light supplied from the light source BL (k +1) to the light guide plate lg (k) is disposed.

By thus interposing the light shielding member 31 between the light guide plate LG (k) and the light source BL (k +1), for example, between the superimposed light guide plates LG (k) and LG (k +1) shown in fig. 12(b), it is possible to prevent light which does not leak from the light source BL (k +1) and enters the corresponding light guide plate LG (k +1) from entering the light guide plate LG (k) superimposed on the light source BL (k + 1).

Further, by providing a reflecting sheet such as a diffusing reflecting sheet as the light shielding member 31 on the rear surface of the light guide plate lg (k), the light propagating through the light guide plate lg (k) can be sufficiently mixed. In this case, color mixing properties can be improved.

The light-shielding body 31 is preferably two types of reflective sheets, i.e., a reflective sheet having high light-shielding property such as a regular reflective sheet and a reflective sheet having high reflectivity such as a diffusive reflective sheet. This can provide a higher effect.

In order to efficiently guide light from light guide region 3 to illumination region 4, it is preferable that light guide region 3 not be subjected to processing or processing such as texturing as described above. However, in the case where light-shielding body 31 such as a reflecting sheet is provided on the front and back surfaces of light guide region 3 as shown in fig. 12(b), the above-described processing or processing such as texturing may be performed not only on illumination region 4 but also on light guide region 3 as long as light is not emitted from light guide region 3 to the outside.

For example, in the case where the stepped portion 11 is provided between the light guide region 3 and the illumination region 4 as shown in fig. 12(b), in order to avoid a decrease in the intensity of light emitted from the vicinity of the stepped portion 11 of the light emitting surface 5, as shown in fig. 12(b), the boundary portion between the light guide region 3 and the illumination region 4 may be subjected to treatment or processing such as texturing under the condition that measures are taken to prevent light from being emitted from the light guide region 3 to the outside, although the size of the stepped portion 11 is also related to the size of the stepped portion 11.

According to the present embodiment, in any of the above-described illumination devices L, the amount of light (emission intensity) emitted from each of the light-emitting portions 9 can be independently adjusted by independently adjusting the amount of light of the light source 21 corresponding to each of the light-emitting portions 9.

In addition, a control circuit (control means) for controlling the amount of illumination light of the light source 21 may be provided in the illumination device L itself or may be provided separately from the illumination device L.

Fig. 13 is a block diagram showing an example of the configuration of a main part of the illumination device L according to the present embodiment.

The lighting device L includes: a light source unit 20 composed of a light source 21 and a light guide plate 1; and a lighting control circuit 34 as the control circuit. As described above, the specific configuration of the light source unit 20 is not shown in fig. 13.

The light source unit 20 has a plurality of (for example, Q ≧ 2) divided illumination regions as the light emitting section 9.

The lighting control circuit 34 controls the amount of illumination light of the light source 21 based on the emission intensity of each of the plurality of light emitting units 9. The light source 21 is, for example, the LED described above.

An irradiation signal for controlling the amount of light emission is input to the lighting control circuit 34 at a certain cycle for each light emitting unit 9.

The lighting control circuit 34 controls the intensity of the illumination light by changing the ratio of the lighting period (illumination period) and the extinguishing period (non-illumination period) per unit time of the corresponding light source 21 in accordance with the light emission amount specified by the illumination signal. That is, the illumination period of the light source 21 is made longer in the frame period of bright light emission, and the illumination period of the light source 21 is made shorter in the frame period of dark light emission.

If the input cycle of the control signal is H, the maximum light amount is Wmax, and the specified light amount of the control signal at a certain time is W, the lighting period T of the light source 21 is represented by T ═ hx (W/Wmax). By performing the above control for each light emitting unit 9, the light emission amount of all the light emitting units 9 can be independently adjusted.

As described above, the lighting control circuit 34 controls the intensity of the illumination light by changing the ratio of the illumination period and the non-illumination period per unit time of the light source 21. That is, the lighting control circuit 34 adjusts the light emission amount (illumination light amount) of the light source 21 of each light emitting section 9 by making the light amount at the time of light emission constant and adjusting the light emission time, thereby independently adjusting the light emission intensity. In the present embodiment, the adjustment of the light emission amount of the light source 21 is performed by turning on and off the light source 21 as described above. The illumination light intensity of each light emitting unit 9 may be adjusted to white by performing area light emission only in black and white, or may be independently adjusted to R, G, B three colors by performing area light emission separately for each R, G, B.

In the present embodiment, as described above, the light sources 21 are provided in a one-to-one manner with respect to the light emitting units 9. When the light sources 21 are provided one for one with respect to the light emitting units 9, control is easy, and the illumination area 4 can be subdivided. However, the present embodiment is not limited to this, and a plurality of light sources 21 may be provided corresponding to the light emitting portions 9 as shown in fig. 14.

For example, when the light emitting region (the light emitting surface LA or the area of each light emitting part 9) is expanded, two or more light sources 21 may be used to irradiate one light emitting part 9 when the light amount of one light source 21 is insufficient for one light emitting part 9. That is, at least one light source 21 may be provided for each light emitting unit 9.

In the case where a plurality of light sources 21 are provided for each light emitting unit 9 as described above, each light source 21 is preferably arranged uniformly in each light emitting unit 9.

In the present embodiment, as described above, the case where the light source 21 is provided on one end surface of the light guide plate 1 is described as an example, but the present embodiment is not limited to this.

The light linearity is high, and from the viewpoint of the utilization efficiency, it is preferable that the light source 21, the light guiding region 3, and the illumination region 4 are arranged on a straight line, and the light source 21 is preferably arranged on one end surface of the light guide plate 1. This allows the light emitted from the light source 21 to be guided to the illumination region 4 without being bent undesirably.

However, as long as light emitted from the light source 21 can be guided to the illumination region 4 through the light guide region 3, the light source 21 may be provided at a position facing the light guide region 3 on the lower surface of the light guide plate 1.

For example, the following structure may be adopted: the light source 21 is provided at the end portion of the lower surface side of the light guide plate 1 or in the vicinity thereof by bending the end face of the light guide region 3 of the light guide plate 1, or by folding a reflector, not shown, at the end portion of the light guide plate 1 to the lower surface side of the light guide plate 1 and enclosing the light source 21 in the reflector.

In the present embodiment, a case where a point-like light source is used as the light source 21 is described as an example, but the present embodiment is not limited to this.

When the light source 21 is a point light source, there is an advantage that miniaturization and subdivision of the illumination region 4 are easy. In addition, when the light source 21 is a point-like light source, since light emitted from the light source 21 is radially diffused, even if the light guide region 3 has a structure in which the light guide portion 3A is connected as described above, light is less likely to leak in the lateral direction with respect to the light source 21. Therefore, light can be easily and reliably prevented from leaking to the adjacent light guide block 1A via the light guide region 3.

However, the linear light source 21 may be a light source that is designed to have a size of the linear light source, a size of the light emitting unit 9, and a length and a type of the divided units in the embodiment described later. In other words, a point-like light source is preferably used as the light source 21, but a point-like light source is not necessarily used, and a linear light source may be provided corresponding to each light emitting section 9.

In order to improve the luminance uniformity of each light source unit 20, it is preferable to adopt a tandem structure in which the light guide region 3 of one light source unit 20 is superimposed on the illumination region 4 of the other light source unit 20, and a light emitting surface 5 of each light source unit 20 forms a single planar light emitting region (light emitting surface LA). However, the present embodiment is not limited to this.

For example, the adjacent light source units 20 may be arranged such that the light guide region 3 of one light source unit 20 is exposed between the illumination region 4 of one light source unit 20 and the illumination region 4 of the other light source unit 20, and the illumination region 4 of one light source unit 20 and the illumination region 4 of the other light source unit 20 are separated from each other. Further, a configuration may be adopted in which a step is provided between the illumination region 4 of one light source unit 20 and the illumination region 4 of the other light source unit 20. However, since light is not actually emitted from the light guide region 3, the light source units 20 are preferably arranged in series so that the illumination regions 4 are arranged as close as possible to each other.

In the present embodiment, as shown in fig. 12(a) and (b), the adjacent light source units 20 are arranged in series such that the divided portions of the light source units 20 are aligned in a straight line.

For example, the light source units 20 may overlap each other with respect to the adjacent light source units 20 so that the light emitting portions 9 are staggered in the lateral direction (that is, the divided portions of the adjacent light guide plates 1 are not positioned on a straight line). For example, the light emitting portions 9 may be overlapped in a mosaic arrangement.

In the present embodiment, the case where the divided portions (the slit portion 8 and the notch portion 8A) are provided continuously from one end to the other end of the light emitting portion 9 has been described as an example, but these divided portions may be provided discontinuously instead of being provided discontinuously.

(embodiment mode 2)

The present embodiment will be described below mainly with reference to fig. 15(a) and (b). In the present embodiment, differences from embodiment 1 are described, and components having the same functions as those of embodiment 1 are given the same reference numerals, and description thereof is omitted.

Fig. 15(a) is a plan view showing a schematic configuration of a main part of the illumination device L according to the present embodiment, and fig. 15(b) is a cross-sectional view taken along line D-D of the light guide plate 1 of the illumination device L shown in fig. 15 (a).

In the illumination device L of the present embodiment, the light guide plate 1 is provided with a groove portion 13 (groove) as a dividing portion for limiting the transmission of light, instead of the slit portion 8 shown in fig. 2(a) and (b). That is, the light guide plate 1 of the present embodiment has a structure in which the illumination region 4 is divided into a plurality of light emitting portions 9 by the groove portions 13 instead of the slit portions 8.

In the present embodiment, the light guide region 3 of the light guide plate 1 is continuous, and the illumination region 4 is formed with the groove portion 13 from one end to the other end of the illumination region 4 in parallel with the optical axis direction of the light emitted from the light source 21.

Further, groove portions 13A of 1/2 width of the groove portion 13 are provided opposite the groove portions 13 at both ends of the light guide plate 1 in the direction in which the light emitting portions 9 of the illumination region 4 are arranged. As shown in fig. 15(a) and (b), the illumination device L has the following configuration: in the same plane, the same groove 13 as the groove 13 provided in each light guide plate 1 is formed between the light emitting parts 9 and 9 between the adjacent light guide plates 1 and 1 by the groove 13A provided in the adjacent light guide plate 1.

Therefore, when the light guide plate 1 is divided into a plurality of light guide blocks at the central portion of the groove portion 13 in each light guide plate 1, all the light guide blocks have the same shape. That is, when the illumination region 4 is divided into a plurality of regions at the central portion of the divided portion, the light guide plates 1 have the same shape for each region.

Therefore, in the present embodiment, when a plurality of light source units 20 are arranged in the lateral direction, the light emission is the same in any region. Therefore, the illumination device can reduce light leakage to the adjacent region, maintain the strength of the combined body as the light guide block, and perform uniform light emission in the plane.

In the present embodiment, when the widths of the adjacent groove portions 13A and 13A are c1 and c2, respectively, the above formula (1) is preferably satisfied, and c1 is more preferably satisfied, and c2 is more preferably satisfied, i.e., 1/2 b.

In the present embodiment, as shown in fig. 15(a) and (b), the illumination region 4 is divided into 6 regions in the same manner as the light guide plate 1 shown in fig. 2(a) and (b), but the number of regions is not particularly limited as long as at least one groove portion 13 is provided and the region is divided into two or more regions. The size of each light-emitting portion 9 defined by the groove 13 is not particularly limited.

The light sources 21 provided on the end surface of the light guide plate 1 are provided, for example, one for one with respect to each light emitting portion 9 so as to correspond to the light emitting portions 9 partitioned by the groove portions 13. The light emitted from each light source 21 is guided to each light emitting section 9 partitioned by the groove section 13.

By forming the groove portions 13 in the illumination region 4 as described above, reflection by the groove portions 13 occurs. The light that is not reflected by the groove portion 13 and the light that passes through a part of the region immediately below the groove portion 13 leak to the adjacent light emitting portion 9, but the light guided into the light emitting portion 9 as the destination can be blocked at a certain ratio.

When the groove 13 is not provided, all light incident on the region corresponding to the groove 13 passes through the region. Therefore, by providing the groove portion 13, the emission region of the light emitted from each light source 21 can be limited. Thus, according to the present embodiment, the amount of light emitted from each light-emitting portion 9 can be independently adjusted by independently adjusting the amount of light of the light source 21 corresponding to each light-emitting portion 9. Therefore, in the present embodiment, the illumination luminance can be adjusted for each light emitting unit 9, and the light guide plate 1 having a plurality of independent light emitting units 9 as one light guide plate can be provided.

Further, if the illumination region 4 is completely divided as in embodiment 1, there is an advantage that the contrast between adjacent light emitting parts 9 is high, but in this case, the boundary between the light emitting parts 9 is sharp, and therefore the boundary is conspicuous. However, by dividing the light-emitting portions 9 by the groove portions 13 as described above, the boundaries between the light-emitting portions 9 can be blurred.

Further, according to the present embodiment, unlike embodiment 1, there is no gap penetrating the front and back surfaces of the light guide plate 1 at the boundary between the light emitting parts 9, and the adjacent light emitting parts 9 are connected to each other at the bottom surface of the light guide plate 1 at the boundary, so that there are advantages of high strength and a firm structure.

In the present embodiment, the method for forming the light guide plate 1 and the method for forming the groove portions 13 are not particularly limited, and, for example, the same method as in embodiment 1 can be used. A cutting device for cutting (perforating) the light guide plate 1 to form the groove portions 13 is not particularly limited, and, for example, the same cutting device as in embodiment 1 can be used.

In the present embodiment, the amount of light emitted from the boundary portion (the region corresponding to the upper surface of the groove portion 13 in the present embodiment) is limited. Therefore, the smaller the width of the groove 13 is, the more preferable. The width of the groove 13 is not particularly limited, but is preferably set to 1mm or less. The depth of the groove portion 13 is not particularly limited as long as it is appropriately set so that a desired effect can be obtained from the viewpoint of a balance between an effect of blocking light transmitted into the target light emitting portion 9 and shape strengthening (strength), or from the viewpoint of a balance between a blurring effect of a boundary between the light emitting portions 9 and a contrast and shape strength between adjacent light emitting portions 9.

The groove 13 may be formed on the front surface side of the light guide plate 1 or on the rear surface side. The surface of the light guide plate 1 on which the groove portions 13 are formed is not particularly limited, and may be appropriately set so as to obtain a desired effect from the viewpoint of balance between the contrast between the adjacent light emitting portions 9 and the blurring effect of the boundary between the light emitting portions 9 or uniformity of display.

In the present embodiment, the groove portion 13 may be a concave shape, a V-shaped groove, or a so-called notch. The groove 13 may be formed by fine cracks.

(embodiment mode 3)

The present embodiment will be described below mainly with reference to fig. 16(a) and (b) and fig. 17(a) and (b). In the present embodiment, differences from embodiments 1 and 2 are described, and components having the same functions as those of embodiments 1 and 2 are given the same reference numerals, and description thereof is omitted.

Fig. 16(a) is a plan view showing a schematic configuration of a main part of the illumination device L according to the present embodiment, and fig. 16(b) is a cross-sectional view taken along line E-E of the light guide plate 1 of the illumination device L shown in fig. 16 (a). Fig. 17(a) is a plan view showing a schematic configuration of another illumination device L according to the present embodiment, and fig. 17(b) is a cross-sectional view taken along line F-F of the light guide plate 1 of the illumination device L shown in fig. 17 (a).

The illumination device L according to the present embodiment uses a dividing portion made of a scattering material (light scattering material) as a dividing portion for limiting the transmission of light. More specifically, in the present embodiment, as shown in fig. 16(a), (b) or fig. 17(a), (b), in the illumination region 4, the scattering region constituted by the scattering member 14 is provided in parallel with the optical axis direction of the light emitted from the light source 21. Examples of the scattering member 14 include a scattering wall. The scattering member 14 also includes a directional scattering member (reflection member).

In addition, in the present embodiment, the light guide regions 3 of the light guide plate 1 are connected, and the diffusion member 14 is provided from one end to the other end of the illumination region 4.

Further, at both ends of the light guide plate 1 in the direction in which the light emitting portions 9 of the illumination region 4 are arranged, scattering members 14A of 1/2 width of the scattering member 14 are provided so as to face the scattering member 14. As shown in fig. 16(a) and (b), the illumination device L has the following structure: between the light emitting portions 9 and 9 between the adjacent light guide plates 1 and 1 on the same plane, the scattering member 14 similar to the scattering member 14 provided in each light guide plate 1 is formed by the scattering member 14A provided in the adjacent light guide plate 1.

Therefore, when the light guide plate 1 is divided into a plurality of light guide blocks at the central portion of the scattering member 14, all the light guide blocks have the same shape. That is, when the illumination region 4 is divided into a plurality of regions at the central portion of the divided portion, the light guide plates 1 have the same shape for each region.

Therefore, in the present embodiment, when a plurality of light source units 20 are arranged in the lateral direction, the light emission is the same in any region. Therefore, the illumination device can reduce light leakage to the adjacent region, maintain the strength of the combined body as the light guide block, and perform uniform light emission in the plane.

In the present embodiment, when the widths of the adjacent scattering members 14A and 14A are c1 and c2, respectively, the foregoing formula (1) is preferably satisfied, and c1 — c2 — 1/2b is more preferably satisfied.

In the present embodiment, as shown in fig. 16(a), (b) or fig. 17(a), (b), the illumination region 4 is divided into 6 regions, but the number of regions is not particularly limited as long as at least one scattering member 14 is provided and the region is divided into two or more regions. The size of each light emitting unit 9 divided by the scattering member 14 is not particularly limited.

The light sources 21 provided on the light entrance end surface 2 of the light guide plate 1 are provided, for example, one for one with respect to each light emitting portion 9 so as to correspond to the light emitting portions 9 divided by the scattering member 14. The light emitted from each light source 21 is guided to each light emitting section 9 divided by the scattering member 14. Each light source 21 is disposed such that, for example, the center position thereof is located on an extension of the central axis of each light emitting unit 9.

By providing the scattering member 14 at the boundary portion of each light emitting section 9 as described above, although a part of light leaks to the adjacent light emitting section 9, the light guided into the light emitting section 9 as a destination can be blocked at a certain ratio.

When the scattering member 14 is not provided, all light incident on a region corresponding to the scattering member 14 passes through the region. Therefore, by providing the scattering member 14, the emission region of the light emitted from each light source 21 can be limited. Thus, according to the present embodiment, the amount of light emitted from each light-emitting portion 9 can be independently adjusted by independently adjusting the amount of light of the light source 21 corresponding to each light-emitting portion 9.

Further, according to the present embodiment, as shown in fig. 16(a), (b) or fig. 17(a), (b), the adjacent light emitting portions 9 are connected to each other via the scattering member 14, and therefore, the strength is higher and the structure is stronger than those of embodiments 1 and 2. Therefore, the shape of the light guide plate 1 is stabilized.

In the present embodiment, a method for forming the light guide plate 1 and a method for forming the scattering member 14 are not particularly limited, and, for example, the same methods as those in embodiments 1 and 2 described above can be used.

As an example of the light source unit 20 of the present embodiment, for example, as shown in fig. 16(a) and (b), a structure in which a scattering material is introduced (for example, filled) into the slit portion 8 shown in fig. 2(a) and (b) or, as shown in fig. 17(a) and (b), a structure in which a scattering material is introduced into the groove portion 13 shown in fig. 15(a) and (b) can be cited.

The scattering member 14 can be formed by the following method: for example, a method in which after the slit portion 8 or the groove portion 13 is formed in the light guide plate 1 using a mold or a cutting device, the slit portion 8 or the groove portion 13 is filled with a scattering material alone, or the scattering material is mixed with a base resin and filled; a method of embedding the scattering member 14 in a transparent resin, which is a material of the light guide plate 1, before the transparent resin is cured when the light guide plate 1 is formed using a mold; or a multi-color forming (e.g., two-color forming) method, etc.

The scattering material is not particularly limited as long as it can scatter light, and a conventionally known scattering material can be used. As the scattering material, for example, a pigment such as titanium oxide or silica can be used. Among these scattering substances, a material with low light absorption, such as titanium oxide or silica, is preferably used.

The scattering material can be used in a mixture with a transparent resin as a material of the light guide plate 1, for example. When a scattering material is used in a mixture with the transparent resin as a base resin, the content of the scattering material in the scattering member 14 (i.e., the mixing ratio of the scattering material to the transparent resin) is not particularly limited, and may be appropriately set so as to obtain a desired effect.

Further, the light emitted after being scattered by the scattering member 14 is controlled for the purpose of blurring the boundary lineFor the purpose of improving the emission efficiency, the ratio of the scattering material contained in the scattering member 14 may be changed on the base side and the top side of the scattering member 14 (for example, the bottom and the top of the groove 13).

The width and height of the scattering member 14, that is, the width and height of the slit portion 8 or the groove portion 13 into which the scattering material is introduced may be set in the same manner as in embodiments 1 and 2 described above.

In the present embodiment, as described above, the case where the scattering member 14 containing a scattering material is provided as an example of the divided portion is mainly described. However, the present embodiment is not limited to this, and the boundary between the scattering region and the other region may not be clearly distinguished.

Further, the same effect can be obtained by providing a light-shielding body instead of the scattering material. The light-shielding body is not particularly limited as long as it has light-shielding properties, and for example, a conventionally known light-shielding body can be used.

The divided portions may be provided so as to penetrate the front and back surfaces of the light guide plate 1 as described above, or may be provided from the front surface to the back surface of the light guide plate 1 so as not to penetrate the front and back surfaces of the light guide plate 1. The above-described division portion may be provided from the back surface to the front surface of the light guide plate 1 so as not to penetrate through the front surface and the back surface of the light guide plate 1, or may be provided only inside the light guide plate 1.

(embodiment mode 4)

The present embodiment will be described below mainly with reference to fig. 18. In the present embodiment, differences from embodiments 1 to 3 are described, and components having the same functions as those of embodiments 1 to 3 are given the same reference numerals, and description thereof is omitted.

Fig. 18 is a plan view showing a schematic configuration of a main part of the illumination device L according to the present embodiment.

As shown in fig. 18, in the illumination device L of the present embodiment, as in embodiment 1, the slit portion 8 and the cutout portion 8A are provided in the illumination region 4 from one end to the other end of the illumination region 4 in parallel with the optical axis direction of the light emitted from the light source 21.

The illumination device L according to the present embodiment is different from embodiment 1 in that the slit portion 8 and the cutout portion 8A are provided to extend in a part of the light guide region 3.

Although the light guide regions 3 of the light guide plate 1 are continuous, the slit portion 8 provided in the illumination region 4 extends to a part of the light guide region 3, and thus the light guide region 3 is partially divided into a plurality of regions as well as the illumination region 4.

Therefore, the light guide plate 1 of the present embodiment has a structure equivalent to that of the light guide region 3 in which the adjacent light guide portions 3A provided with the light guide block 1A are partially connected to each other as shown in fig. 2 (a). Although not shown, the light source unit 20 of the present embodiment has a structure in which a plurality of light source blocks 20A are connected to a part of the light guide portion 3A as described above, as shown in fig. 2(a), and the light source block 20A includes the light guide block 1A and the light source 21.

As described above, in the illumination device L of the present embodiment, the slit portion 8 and the cutout portion 8A connected to the illumination region 4 are formed in a part of the light guide region 3, and thus, in addition to the effects (advantages) described in embodiment 1, there is an effect that light emitted from each light source 21 is less likely to leak to a light source block other than the same light source block as the light source 21 (particularly, a region other than the light emitting portion 9 in the same light source block).

As described above, the slit portion 8 is preferably provided in a region where irradiation regions of the adjacent light sources 21 overlap each other. In addition, it is preferable that the slit portion 8 formed by the cutout portions 8A and 8A of the adjacent light source units 20 and 20 is provided also in a region where the irradiation regions of the light sources 21 overlap at the boundary portion of the light source units 20 arranged side by side.

As described above, by forming the slit portion 8 and the cutout portion 8A also in a part of the light guide region 3, the light emitted from each light source 21 can be sufficiently diffused in the light guide region 3, and the light emitted from each light source 21 can be efficiently transmitted and sealed to the light emitting portion 9 as a destination. Thus, according to the above configuration, the luminance control and the luminance equalization can be easily performed for each light emitting section 9.

Here, preferred lengths of the slit portion 8 and the cutout portion 8A in the light guide plate 1 will be described with reference to fig. 18.

Preferable conditions of the slit portion 8 in each light guide plate 1 are the same as those of the slit portion 8 formed by the cutout portion 8A provided in each light guide plate 1. Therefore, in the following description, the slit portion 8 is exemplified, but the same conditions as the slit portion 8 are applied to the notch portion 8A, and more strictly, the slit portion 8 formed by the notch portion 8A.

As described above, the slit portion 8 is preferably provided in a region where irradiation regions of the adjacent light sources 21 overlap each other. As shown in fig. 18, the slit portion 8 preferably includes a point in the illumination region 4 where light incident from the light source 21 provided for the adjacent light emitting portion 9 intersects. As shown in fig. 18, the end of the slit portion 8 on the light source 21 side is preferably located between lines L1 and L2. Here, line L1 is a line that includes a point where light emitted from light source 21 provided to adjacent light emitting unit 9 intersects in a plan view, and extends parallel to the boundary between illumination region 4 and light guiding region 3. Line L2 is a line that includes light source 21 and extends parallel to the boundary between light guide region 4 and illumination region 3. However, the light guiding region 3 is connected at least partially.

That is, when the light source 21 is provided on one end surface of the light guide plate 1, and the illumination region 4 and the light guide region 3 are provided in this order from the light source 21 side to the illumination region 4 along the main surface of the light guide plate 1 as described above, the length in the optical axis direction from the one end surface to the slit portion 8 is preferably equal to or less than the length in the optical axis direction from the one end surface to the point where the light emitted from the adjacent light source 21 intersects.

In fig. 18, as shown by the two-dot chain line, when the light sources 21 are provided on the lower surface side of the light guide plate 1, the slit portion 8 is preferably provided in a region where irradiation regions of adjacent light sources 21 overlap each other. Therefore, in this case, the end of the slit portion 8 on the light source 21 side is also preferably provided between the line L1 and the line L2 indicated by the two-dot chain line, the line L1 includes a point at which light emitted from the light source 21 indicated by the two-dot chain line in fig. 18 provided with respect to the adjacent light emitting portion 9 intersects, and extends parallel to the boundary between the illumination region 4 and the light guide region 3, and the end of the slit portion 8 on the light source 21 side is more preferably provided between the line L1 and the end of the light guide region 3 on the side opposite to the illumination region 4. However, in this case, it is also necessary to assume that at least a part of each light guide portion 3A shown in fig. 2(a) in light guide region 3 is connected.

More specifically, as shown in fig. 18, in the case where an LED is used as the light source 21, when an end portion of the light emitting surface of the LED on a side facing an extension line of the slit portion 8 is a first light emitting surface end, an end portion of the light emitting surface of the LED opposite to the first light emitting surface end is a second light emitting surface end, a distance between the extension line of the slit portion 8 and the first light emitting surface end is a, a distance between the first light emitting surface end and the second light emitting surface end (i.e., a width of the LED) is f, a critical angle at a refractive index of the light guide plate 1 is θ, a length of the slit portion 8 is d, and a length of the light guide plate 1 is e, the length d of the slit portion 8 from the front end surface 12 of the illumination region 4 preferably satisfies d ≧ e- { (a + f) × tan (90- θ) }, more preferably d ≧ e- { a × tan (90- θ) }. This allows the slit 8 to totally reflect all the light emitted from the light source 21.

In other words, the slit portion 8 is preferably provided at a position where the distance (e-d) between the light entrance end face 2 and the end of the slit portion 8 on the light source 21 side satisfies e-d ≦ (a + f) × tan (90- θ), and more preferably at a position satisfying e-d ≦ (a) × tan (90- θ).

Further, according to snell's law, the light incident from the light source 21 to the light guide plate 1 is within the above-mentioned critical angle θ.

When the refractive index of the light guide plate 1 is n1, θ is sin θ 1/n1, and the critical angle θ at the refractive index of the light guide plate 1 is about 39 ° when the light guide plate 1 is polycarbonate (refractive index n1 is 1.59), and about 42 ° when the light guide plate 1 is acrylic (refractive index n1 is 1.49).

In the present embodiment, as described above, the configuration in which the slit portion 8 and the cutout portion 8A are provided in the part of the light guide region 3 and the illumination region 4 is described as an example, but the present embodiment is not limited to this. For example, the slit portion 8 and the notch portion 8A may be replaced with the groove portions 13 and 13A or the scattering members 14 and 14A as described in embodiments 2 and 3. This can provide the above-described effects (advantages) in addition to the effects described in embodiments 2 and 3.

In the present embodiment, the method for forming the light guide plate 1 is not particularly limited, and the same methods as in embodiments 1 to 3 can be used.

(embodiment 5)

The present embodiment will be described below mainly with reference to fig. 19. In the present embodiment, differences from embodiments 1 to 4 are described, and components having the same functions as those of embodiments 1 to 4 are given the same reference numerals, and description thereof is omitted.

Fig. 19(a) is a plan view showing a schematic configuration of a main part of the illumination device L according to the present embodiment, and fig. 19(b) is a sectional view of the light guide plate 1 of the illumination device L shown in fig. 19(a) taken along the line G-G.

As shown in fig. 19, the illumination device L of the present embodiment has a configuration in which the slit portion 8 and the cutout portion 8A provided in the illumination region 4 extend to a part of the light guide region 3, while the light guide region 3 of the light guide plate 1 is continuous, as in embodiment 4.

However, the illumination device L of the present embodiment is different from the above-described embodiment 4 in that the illumination region 4 of the light guide plate 1 is not completely divided by the slit portion 8, and the distal end portions of the illumination region 4 are continuous.

That is, in the light guide plate 1 of the present embodiment, the illumination region 4 is partially divided into the plurality of light emitting portions 9, and the light guide region 3 is also partially divided into the plurality of light guide portions 3A.

That is, as shown in fig. 19(a) and (b), the light guide plate 1 of the present embodiment has a light guide region 3, the light guide region 3 is formed by one-dimensionally arranging a plurality of light guide blocks 1A, adjacent light guide portions 3A of the light guide blocks 1A are partially connected to each other, and the light guide plate 1 of the present embodiment is provided with an optical dividing portion at a portion between adjacent light emitting portions 9, 9. Further, the light source unit 20 of the present embodiment has a structure in which a plurality of light source blocks 20A are connected at a part of the light guide portion 3A and a part of the light emitting portion 9 as described above, and the light source block 20A includes the light guide block 1A and the light source 21.

In the present embodiment, similarly to embodiment 4, it is preferable that the end portion of the slit portion 8 on the light source 21 side is disposed closer to the light source 21 side than a point where light emitted from the light source 21 provided in an adjacent region intersects with, as shown in fig. 18.

In the present embodiment, as described above, the slit portion 8 and the cutout portion 8A are provided in a part of the light guide region 3 and a part of the illumination region 4, but the present embodiment is not limited thereto. For example, instead of the slit portion 8 and the notch portion 8A, the grooves 13 and 13A or the scattering members 14 and 14A may be provided as in the embodiments 2 and 3.

According to the present embodiment, the effects described in embodiment 4 above can be obtained, and in the case where the front end portions of the divided illumination regions 4 are connected to each other without providing a divided portion as described above, particularly in the case where the light guide plate 1 is integrally formed of the same material, the structure can be further strengthened.

In the present embodiment, the method for forming the light guide plate 1 is not particularly limited, and can be appropriately selected from the methods for forming described in embodiments 1 to 3, for example.

(embodiment mode 6)

The present embodiment will be described below mainly with reference to fig. 20(a) and (b). In the present embodiment, differences from embodiments 1 to 5 are described, and components having the same functions as those of embodiments 1 to 5 are given the same reference numerals, and description thereof is omitted.

Fig. 20(a) and (b) are plan views each showing an example of a schematic configuration of a main part of the illumination device L according to the present embodiment.

In the above embodiments 1 to 5, the case where the boundary portion of each light emitting portion 9 is formed in a linear shape was described as an example, but in the present embodiment, the case where the boundary portion of each light emitting portion 9 is formed in a zigzag shape (zigzag) was described as an example.

Each light guide plate 1 used in the illumination device L of the present embodiment is the same as the light guide plate 1 described in embodiments 1 and 2 described above, except that, for example, as shown in fig. 20(a) and (b), the slit portion 8 and the cutout portion 8A shown in fig. 2(a) or the groove portions 13 and 13A shown in fig. 15(a) are formed in a zigzag shape.

As described above, the light emitting portions 9 are divided to have jagged boundaries, and thus, in addition to the effects described in embodiments 1 and 2, a blurring effect of blurring the boundaries between the light emitting portions 9 and 9 can be obtained. Alternatively, the blurring effect can be improved.

In the present embodiment, as described above, the case of using the light guide plate 1 in which the slit portion 8 shown in fig. 2(a) or the groove portion 13 shown in fig. 15(a) is formed in a zigzag shape has been mainly described as an example. However, the light guide plate 1 used in the present embodiment is not limited to this, and the light guide plate 1 described in embodiments 3 to 5 may have a structure in which each of the divided portions is formed in a zigzag shape, as long as the boundary between the light emitting portions 9 has a concave-convex shape. The shape of the boundary is not limited to the zigzag shape, and may be, for example, a wave shape.

In the present embodiment, the pitch P between adjacent saw teeth (the distance between the apexes of the saw teeth), the angle Q formed by the saw teeth, and the height h of the saw teeth in the slit portion 8 or the groove portion 13 are not particularly limited, and may be appropriately set so that a desired blurring effect can be obtained.

(embodiment 7)

The present embodiment will be described below mainly with reference to fig. 21(a) and (b). In the present embodiment, differences from embodiments 1 to 6 are described, and components having the same functions as those of embodiments 1 to 6 are given the same reference numerals, and description thereof is omitted.

Fig. 21(a) is a plan view showing a schematic configuration of a main part of the illumination device L according to the present embodiment, and fig. 21(b) is a sectional view of the light guide plate 1 of the illumination device L shown in fig. 21(a) taken along the H-H line.

In the illumination device L of the present embodiment, as shown in fig. 21(a) and (b), a layer (hereinafter referred to as a "low refractive index layer") 16 having a refractive index smaller than that of a portion other than the divided portion is provided in the light guide plate 1 as the divided portion for restricting the transmission of light. Here, the fact that the refractive index is smaller than the portion other than the divided portion means that the refractive index is smaller than the material of the light guide plate 1.

Further, at both ends in the direction in which the light emitting portions 9 are arranged in the illumination region 4 of the light guide plate 1, a low refractive index layer 16A of 1/2 width of the low refractive index layer 16 is provided so as to face the low refractive index layer 16. As a result, as shown in fig. 21(a) and (b), in the lighting device L of the present embodiment, the low refractive index layer 16 similar to the low refractive index layer 16 provided in each light guide plate 1 is formed between the light emitting portions 9 and 9 between the adjacent light guide plates 1 and 1 on the same plane, by the low refractive index layer 16A provided in the adjacent light guide plate 1.

Therefore, when the light guide plate 1 is divided into a plurality of light guide blocks at the central portion of the low refractive index layer 16, all the light guide blocks have the same shape. That is, when the illumination region 4 is divided into a plurality of regions at the central portion of the divided portion, the light guide plates 1 have the same shape for each region.

In the present embodiment, when the widths of the adjacent low refractive index layers 16A and 16A are c1 and c2, respectively, the above formula (1) is preferably satisfied, and c1 is more preferably satisfied, and c2 is more preferably satisfied, i.e., 1/2 b.

The low refractive index layers 16 and 16A preferably satisfy the total reflection condition (that is, are made of a material satisfying the total reflection condition), and more preferably are provided so that all the light emitted from the light source 21 is totally reflected as described above.

As described above, according to snell's law, the light incident from the light source 21 to the light guide plate 1 is within θ. When the refractive index of the light guide plate 1 is n1, θ is expressed as sin θ being 1/n1 as described above.

Thus, the condition that light incident on the light guide plate 1 is totally reflected by the low refractive index layer 16 (i.e., the low refractive index layer 16 provided on the light guide plate 1, or the low refractive index layer 16 formed of the adjacent low refractive index layers 16A, 16A) and is conducted within the light guide plate 1 is that sin (90- θ) is n2/n1 according to snell's law, when the refractive index of the low refractive index layer 16 is assumed to be n 2. According to this formula, sin (90- θ) ═ cos θ, (sin θ)²+(cosθ)²1, so 1/(n1)²+(n2)²/(n1)²When n2 is solved for 1, then

Thus, in order to satisfy the total reflection condition, the refractive index n2 of the low refractive index layer 16 may satisfy the following formula (2):

as described above, in the case where the light guide plate 1 is made of acrylic resin, n1 is 1.49, and therefore, in order to satisfy the total reflection condition, the low refractive index layer 16 may satisfy n2 < 1.10. In addition, when the light guide plate 1 is made of polycarbonate, n1 is 1.59, and therefore the low refractive index layer 16 may satisfy n2 < 1.236 in order to satisfy the total reflection condition.

An example of a layer satisfying such a condition is an air layer (n2 ═ 1.0). That is, the low refractive index layer 16 may be, for example, a slit portion 8. However, the present embodiment is not limited thereto, and the low refractive index layer 16 may be a layer having a smaller refractive index than a portion of the light guide plate 1 other than the low refractive index layer 16, and may be a layer that appropriately satisfies the formula (2).

That is, as the dividing portion, for example, only a reflective layer can be used, but in this case, the light use efficiency is lowered due to the reflectance. Therefore, the dividing portion is more preferably made of a material that satisfies the total reflection condition.

In the present embodiment, when a plurality of light source units 20 are arranged in the lateral direction, the light emission is the same in any region. Therefore, the illumination device can reduce light leakage to the adjacent region, maintain the strength of the combined body as the light guide block, and perform uniform light emission in the plane.

(embodiment mode 8)

The present embodiment will be described below mainly with reference to fig. 22 to 25. In this embodiment, a liquid crystal display device is taken as an example of an electronic device including the illumination device L described in embodiments 1 to 7. In the present embodiment, the same reference numerals are given to components having the same functions as those in embodiments 1 to 7, and the description thereof will be omitted.

Fig. 22 is a cross-sectional view schematically showing a schematic configuration of a main part of the liquid crystal display device of the present embodiment. Fig. 23(a) is a plan view showing an example of a schematic configuration of an illumination device provided in the liquid crystal display device shown in fig. 22, and fig. 23(b) is an end view schematically showing the schematic configuration of the liquid crystal display device shown in fig. 22 when the liquid crystal display device is viewed from the opposite side of the light source in the illumination device shown in fig. 23 (a). In fig. 23(a), the optical sheet is not shown.

In the present embodiment, a case where the tandem-type illumination device 30 described in fig. 12(a) and (b) is mainly used as the illumination device L of the present embodiment will be described as an example.

As shown in fig. 22, the liquid crystal display device 40 of the present embodiment includes a liquid crystal panel 41 (display panel); and an illumination device 30 provided on the opposite side (rear side) of the display surface of the liquid crystal panel 41. The illumination device 30 is also referred to as a backlight, and irradiates the liquid crystal panel 41 with light.

For convenience of explanation, the present embodiment will be described with reference to a principal surface on the light emission side of each light guide plate 1, that is, a surface (light-emitting surface LA) of the illumination device 30 facing the liquid crystal panel 41 as an upper surface or a front surface, and a principal surface on the opposite side as a lower surface or a back surface.

The liquid crystal panel 41 has the same configuration as a general liquid crystal panel used in a conventional liquid crystal display device, and therefore, detailed description and illustration thereof are omitted. The structure of the liquid crystal panel 41 is not particularly limited, and a known liquid crystal panel can be applied as appropriate. The liquid crystal panel 41 includes, for example: an active matrix substrate on which a plurality of TFTs (thin film transistors) are formed; the counter substrate facing the active matrix substrate has a structure in which a liquid crystal layer is sealed between the pair of substrates with a sealing material. As the counter substrate, for example, a CF (color filter) substrate can be used.

On the other hand, as shown in fig. 22 and fig. 23(a) and (b), the illumination device 30 of the present embodiment includes the light guide plate 1, the light source 21, the substrate 42, the optical sheet 43, and the light shield 31.

In the present embodiment, as described above, the plurality of light source units 20 described in embodiment 1 are partially overlapped in a staggered manner in the optical axis direction, and are arranged in a direction perpendicular to the optical axis direction. Therefore, the lighting device 30 has a structure in which the plurality of light guide plates 1 and the plurality of light sources 21 provided in the respective light guide plates 1 are provided, and the substrate 42 and the light shielding member 31 are provided in the respective light guide plates 1.

In the present embodiment, 5 light source units 20 are overlapped in a staggered manner in the optical axis direction of the light emitted from the light source 21, and 2 light source units are arranged in parallel in the direction perpendicular to the optical axis direction. However, as described above, the number of the light guide plates 1 to be stacked may be 2 or more, and the number of the light guide plates 1 to be arranged may be 2 or more. As described above, the light source unit 20 may be disposed only in the direction perpendicular to the optical axis direction.

As shown in fig. 22 and fig. 23(a) and (b), the substrate 42 is provided along the light entrance end surface 2 of each light guide plate 1. The light sources 21 are mounted on the substrate 42 in a row.

A drive circuit (driver), not shown, for controlling the lighting of each light source 21 is disposed on the lower surface side of the substrate 42. That is, the driving circuit is mounted on the same substrate 42 together with the light sources 21. In the present embodiment, the light emission amount of each light emitting unit 9 in each light guide plate 1 can be independently adjusted by controlling the lighting of each light source 21.

The light source 21 is preferably disposed as close as possible to the light guide plate 1. By disposing the light source 21 and the light guide plate 1 close to each other, the light entrance efficiency from the light source 21 to the light guide plate 1 can be improved.

The optical sheets 43 may be provided on the upper surfaces of the light-emitting surfaces 5 of the light guide plates 1, respectively, or may be integrally formed so as to entirely cover the light-emitting surfaces 5 of the light guide plates 1.

That is, the optical sheet 43 is formed of a plurality of sheets stacked on the upper surface side of the light guide plate 1, and uniformizes and condenses the light emitted from the light guide plate 1, and irradiates the light to the liquid crystal panel 41.

The optical sheet 43 is generally composed of a diffusion plate for irradiating the liquid crystal panel 41 with uniform light, a diffusion sheet for condensing light and scattering the light, a lens sheet for condensing light and increasing the luminance in the front direction, a polarizing reflection sheet for reflecting one polarization component (single polarization component) of the light and transmitting the other polarization component (single polarization component) to increase the luminance of the liquid crystal display device 40, and the like. They can be used in combination as appropriate in accordance with the price and performance of the liquid crystal display device 40.

Further, the light-shielding body 31 is provided on the back surface of the light guide plate 1 as described above. The light-shielding body 31 is preferably provided with a reflection sheet for reflecting a part of the light irradiated from the light guide plate 1 and the light returned via the optical sheet 43, and more preferably provided with two types of reflection sheets as described above. The light-shielding body 31 is not provided only in the region facing the light source 21 on the back surface side of each light guide plate 1, but is disposed over the entire back surface of each light guide plate 1, whereby more light can be reflected toward the liquid crystal panel 41.

According to the above configuration, the light emitted from the point-like light source 21 enters the light guide plate 1 while being subjected to the scattering action and the reflection action, is emitted from the light emitting surface 5, and reaches the liquid crystal panel 41 through the optical sheet 43.

Next, the operation principle of the area active driving using the illumination device 30 will be described below with reference to fig. 24.

When a video signal is input to the liquid crystal display device 40, area active processing is performed based on the video signal (input image). That is, the lighting control circuit 34 changes the amount of illumination light of the LED (light source 21) in accordance with the video signal, for example, by using the irradiation signal based on the video signal transmitted to each light emitting unit 9, thereby independently dimming each of the plurality of light emitting units 9 (light emitting areas) with respect to the input image. Thus, LED data corresponding to the brightness of the input image is generated. In addition, for example, in the case of the 52-type liquid crystal display device 40, the number of light emitting regions is set to 48 × 24.

On the other hand, LCD data to be displayed on the liquid crystal panel 41 is created based on the input image and the LED data. The LED data and the LCD data are superimposed on each other by the lighting device 30 (LEDBLU: backlight unit) and the liquid crystal panel 41, whereby an output image with a wide viewing angle and wide color reproducibility is obtained with high contrast.

Next, the luminance control of the illumination light of each light emitting section 9 in the illumination device 30 (backlight) corresponding to the brightness of the image displayed in the display region of the liquid crystal display device 40 will be specifically described with reference to fig. 25.

Fig. 25 is a block diagram showing a schematic configuration of a main part of the liquid crystal display device 40.

The light emitting surface LA of the illumination device 30 is divided into M rows × N columns of divided illumination regions (light emitting unit 9) in a matrix, for example, and lighting-off control is performed for each divided illumination region. That is, in the present embodiment, the light guide plate 1 (tandem light guide plate) shown in fig. 22 and fig. 23(a) and (b) after being divided into regions is used as the light guide plate in the illumination device 30, and the light amount is adjusted for each region.

The liquid crystal panel 41 can be virtually divided into divided display regions corresponding to the divided illumination regions of the illumination device 30. The liquid crystal display device 40 can be virtually divided into divided regions corresponding to the divided illumination regions of the illumination device 30. The divided region and the divided illumination region preferably correspond to an integral multiple (but 1 time or more) of one pixel of the liquid crystal display device 40.

As shown in fig. 25, the liquid crystal display device 40 includes, as a drive circuit (control means), a maximum grayscale level detection circuit 44 and a grayscale conversion circuit 45 in addition to the lighting control circuit 34. Note that, for convenience of explanation, in fig. 25, the lighting control circuit 34 is shown as a single driving circuit separately from the illumination device 30, but as described above, the lighting control circuit 34 may be provided separately from the illumination device 30 or may be provided integrally with the illumination device 30.

The lighting control circuit 34 controls the intensity of illumination light by changing the ratio of the illumination period per unit time and the non-illumination period of the light source 21 for each of the divided illumination regions of the corresponding illumination device 30 as described above, based on the maximum grayscale level in one frame period for each of the divided regions of the liquid crystal display device 40 (liquid crystal panel 41) detected by the maximum grayscale level detection circuit 44.

In the present embodiment, as the unit time, for example, the ratio of the illumination period to the non-illumination period in one frame period is changed.

The maximum gray scale level may be controlled for each color R, G, B, or may be controlled for white.

That is, the intensity of illumination light in each of the divided illumination regions may be independently adjusted for R, G, B three colors (that is, region-by-region light emission is performed for R, G, B), or white color adjustment (that is, region-by-region light emission is performed only for black and white).

The gradation conversion circuit 45 converts the display image signal based on the maximum gradation level in one frame period for each divided region in the liquid crystal display device 40 detected by the maximum gradation level detection circuit 44, and creates an input image signal to be input to the liquid crystal panel 41 for each divided display region.

Further, the ratio of the illumination and non-illumination periods of the illumination device 30 controlled by the lighting control circuit 34 in accordance with the maximum gray scale level detected by the maximum gray scale level detection circuit 44 is controlled such that the luminance of the illumination light is high in the illumination region (divided illumination region) corresponding to the display region (divided region) displaying the bright image and the luminance of the illumination light is low in the illumination region (divided illumination region) corresponding to the display region (divided region) displaying the dark image as described in embodiment 1, whereby the liquid crystal display device 40 capable of displaying an image with a wide dynamic range and a high contrast feeling can be realized.

As described above, in the liquid crystal display device 40 of the present embodiment, each divided region is divided into M rows × N columns in a matrix, the maximum grayscale level detection circuit 44 detects the maximum grayscale level of the display image signal for each image displayed in each divided region, the lighting control circuit 34 changes the ratio of the lighting period to the non-lighting period of the corresponding divided lighting region in the lighting device 30 to control the luminance of the illumination light to the liquid crystal panel 41, and the grayscale conversion circuit 45 optimizes the input image signal to the liquid crystal panel 41 for each divided display region based on the maximum grayscale level detected by the maximum grayscale level detection circuit 44.

By performing the above control, it is possible to perform extremely fine image display with a high contrast feeling, compared to when an illumination device that continuously irradiates the entire light emitting surface with a constant light amount is used as a backlight. That is, according to the present embodiment, a thin and high-quality large-sized liquid crystal display device 40 can be realized.

In the above description, the case where the tandem-type illumination device 30 described in fig. 12(a) and (b) is used as the illumination device L of the present embodiment has been described as an example, but the present embodiment is not limited thereto, and the illumination devices L described in the above embodiments can be used as appropriate.

In this embodiment, a liquid crystal display device is described as an example of the electronic device according to this embodiment, but the present embodiment is not limited to this. The electronic device may be a display device other than a liquid crystal display device, and the illumination device L of the present embodiment can be applied to various electronic devices requiring an illumination device.

(embodiment mode 9)

The present embodiment will be described below mainly with reference to fig. 26 to 28. In the present embodiment, a television receiver (liquid crystal television) using the liquid crystal display device 40 described in embodiment 8 is described as an example of an electronic device including the lighting device L described in embodiments 1 to 8. In the present embodiment, the same reference numerals are given to the components having the same functions as those in embodiments 1 to 9, and the description thereof will be omitted.

Fig. 26 is a block diagram showing a schematic configuration of a liquid crystal display device 40 for a television receiver according to the present embodiment. Fig. 27 is a block diagram showing a relationship between the tuner section and the liquid crystal display device 40 in the television receiver shown in fig. 26. Fig. 28 is an exploded perspective view of the television receiver shown in fig. 26.

As shown in fig. 26, the liquid crystal display device 40 includes a Y/C separation circuit 50, a video chromaticity circuit 51, an a/D converter 52, a liquid crystal controller 53, a liquid crystal panel 41, a backlight drive circuit 54, a lighting device L as a backlight, a microcomputer 55, and a gradation circuit 56.

In the liquid crystal display device 40 having the above-described configuration, first, an input video signal of a television signal is input to the Y/C separation circuit 50, and is separated into a luminance signal and a color signal. The luminance signal and the color signal are converted into R, G, B, which are three primary colors of light, by the video chromaticity circuit 51, and the analog RGB signals are converted into digital RGB signals by the a/D converter 52 and input to the liquid crystal controller 53.

The liquid crystal panel 41 receives RGB signals from the liquid crystal controller 53 at predetermined timings, and supplies the RGB gradation voltages from the gradation circuit 56 to the liquid crystal panel, thereby displaying an image. The microcomputer 55 controls the entire system including these processes.

The display can be performed based on various video signals, such as a video signal based on television broadcasting, a video signal captured by a video camera, a video signal supplied via a network line, and a video signal recorded on a DVD.

Further, the tuner unit 60 shown in fig. 27 receives television broadcasting and outputs a video signal, and the liquid crystal display device 40 performs image (video) display based on the video signal output from the tuner unit 60.

When the liquid crystal display device 40 having the above-described configuration is a television receiver, for example, as shown in fig. 28, the liquid crystal display device 40 is sandwiched between a first housing 61 and a second housing 62 so as to be surrounded thereby.

The first housing 61 is provided with an opening 61a through which an image displayed on the liquid crystal display device 40 passes.

The second housing 62 covers the back surface side of the liquid crystal display device 40, is provided with an operation circuit 63 for operating the liquid crystal display device 40, and has a support member 64 attached therebelow.

As described above, in the television receiver and the video monitor having the above-described configuration, the liquid crystal display device 40 is used as a display device, and thus, a video having high contrast, good moving image characteristics, and high display quality can be displayed.

As described above, the illumination device according to each of the above embodiments includes the plurality of light emitting portions in the illumination region by the optical dividing portion. Therefore, the light guide plate of the above lighting device has a structure equivalent to: the light guide unit includes a plurality of light guide blocks each having a light emitting portion and a light guide portion, and the light guide blocks are connected to each other at the light guide portion in a first direction in which the light emitting portions are arranged.

In the lighting device, the light emitted from each light source can be confined to the light emitting section as a destination with a simple configuration by providing the dividing section between the light emitting sections, and light leakage to the adjacent light emitting sections can be suppressed or avoided.

Further, the above-described illumination device has a plurality of light source units including a light guide plate and a plurality of light sources. The light source units are arranged in the first direction. In the illumination device, the dividing portion is provided in at least a part of the light emitting portions between the light source units adjacent to each other in the first direction, so that even when the plurality of light source units are arranged in the first direction, the light emitting aspect is the same in any part of the illumination region. Therefore, uniform light emission in the plane can be performed.

Thus, according to the above embodiments, it is possible to provide an illumination device that can reduce light leakage to adjacent regions, can maintain the strength of a combined body as a light guide block, and can emit light uniformly in any part of an illumination region.

Preferably, the width of the dividing portion provided between the light emitting portions in each of the light source units is the same as the width of the dividing portion provided between the light source units adjacent to each other in the first direction.

In addition, it is preferable that the dividing section between the light emitting sections between the light source units adjacent to each other in the first direction is provided at least one end of each light source unit in the first direction, the widths of the dividing sections at both ends of each light source unit in the first direction are c1 and c2, respectively, the width of the dividing section provided between the light emitting sections in each light source unit is b, and c1 is not less than 0, c2 is more than 0, and b is more than 0, so that the following formula (1) is satisfied

c1+c2＝b……(1)

More preferably c1 ═ c2 ═ 1/2 b.

According to the above-described configurations, the width of the divided portion provided between the light emitting portions in each light source unit can be easily made to coincide with the width of the divided portion provided between the light source units adjacent to each other in the first direction, and in particular, when c1 is c2 is 1/2b, the light guide plate can be formed so that all the light guide blocks have the same shape.

As the dividing portion, for example, a slit or a groove provided in the light guide plate can be used.

By forming a slit in the illumination region, reflection by the slit is generated. All light reaching the slit at an angle satisfying the condition of the total reflection angle (an angle exceeding the critical angle θ which is the minimum incident angle for total reflection) is reflected. A part of light that does not satisfy the total reflection angle condition leaks to an adjacent light emitting portion, but if no slit is provided, all light incident on a region corresponding to the slit transmits through the region.

Therefore, by providing slits as the dividing portions, it is possible to limit the light emitting regions of the light emitted from the respective light sources, and to completely divide the illumination region into the plurality of light emitting portions. As a result, the contrast between adjacent light emitting sections can be improved.

On the contrary, when the light guide plate is provided with the groove as the dividing portion, the portion directly below the groove is connected to the adjacent light emitting portions, and therefore, the boundary between the light emitting portions can be blurred.

When the illumination region is formed with the groove, reflection due to the groove is also generated. Light that is not reflected by the grooves and light that passes through a part of the region directly below each groove connected to an adjacent light-emitting portion leak to the adjacent light-emitting portion, but light that is transmitted into the light-emitting portion as a destination can be blocked at a certain rate.

In the case where the groove is not provided, all of the light incident on the region corresponding to the groove transmits through the region. Therefore, by providing the groove as the dividing portion, the light emission region of the light emitted from each light source can be limited.

Further, according to the above configuration, the adjacent light emitting portions are connected to each other at the bottom surface of the light guide plate at the boundary portion thereof, and therefore, there is an advantage that the strength is higher and the structure is more firm.

The divided portions may be formed of a layer having a refractive index smaller than that of the light emitting portions divided by the divided portions. In this case, reflection by the dividing portion occurs, and particularly, all light reaching the dividing portion at an angle satisfying the total reflection angle condition is reflected.

In this case, the light-emitting regions of the light emitted from the respective light sources can be restricted by providing the layer as the dividing portion, and the contrast between adjacent light-emitting portions can be improved.

In addition, each of the divided portions preferably satisfies a total reflection condition. The total reflection condition is expressed by the following formula (2) using the critical angle θ according to the law of fresnel when the refractive index of the portion other than the divided portion (i.e., the material of the light guide plate) is n1 and the refractive index of the divided portion is n 2:

thus, the dividing portion preferably satisfies the formula (2). Such a layer is preferably an air layer of the slit or groove.

The dividing part may be formed of a light scattering material or a light shielding material.

According to the above configuration, although a part of light leaks to the adjacent light emitting sections, light transmitted to the inside of the target light emitting section can be blocked at a certain rate.

When the dividing portion is not provided, all light incident on a region corresponding to a boundary portion between adjacent light emitting portions transmits through the region. In this way, by providing the divided portion composed of the light scattering material or the light blocking member in the illumination region, the light emission region of the light emitted from each light source can be restricted.

In the above configuration, the light emitting portions are connected by the dividing portion made of the light scattering material or the light shielding member, and no space portion is present in the illumination region. Therefore, the strength is higher and the structure is stronger than the case where the divided portion is a groove. Therefore, the shape of the light guide plate is stabilized.

In addition, the dividing portion preferably includes a point in the illumination region where light incident from a light source provided to an adjacent light emitting portion intersects.

This can suppress or prevent light emitted from adjacent light sources from being mixed, and thus can facilitate area control.

Preferably, the light emitting portions are directly connected to each other at an end portion of the illumination region opposite to the light guide region without the partition portion.

By adopting the structure, the strength is higher, and the structure is more stable and firmer.

On the other hand, when the dividing portion is provided from one end to the other end of the illumination region, light does not leak from the end portion of the light emitting portion to the adjacent illumination region, and therefore the contrast between the adjacent light emitting portions can be improved.

The dividing portion may have a concave-convex shape (for example, a saw-tooth shape, a wavy shape, or the like). In this case, the boundaries between the regions can be blurred.

In the illumination device, it is preferable that the other light source unit is disposed so that the illumination region of the other light source unit overlaps at least a part of the light guide region of the one light source unit in the second direction of each light source unit.

That is, each of the light source units preferably includes: a light guide region in which at least a part of adjacent light guide portions are connected to each other; and an illumination region including the light emitting section and the dividing section, wherein the plurality of light source units are two-dimensionally arranged, are adjacent to the other light source units in the second direction of the light source units, and overlap the illumination region of the other light source unit in at least a part of the light guide region of one light source unit adjacent in the second direction.

According to the above configuration, the number of the light emitting units can be increased two-dimensionally. Therefore, a continuous wide light emitting region can be realized regardless of the size of one light guide plate.

In the lighting device, since the light guide region has high intensity, the light source units are arranged two-dimensionally as described above, that is, the light guide region of each light guide plate is made thin, and the intensity of the connection portion of each light guide block is also high. Therefore, the lighting device has a strong structure as a combination of the light guide blocks.

In addition, the display device with the illuminating device can realize enough brightness and excellent brightness uniformity, and the illuminating device has high intensity and firm structure.

In addition, the display device having the illumination device can be thinned, and can realize sufficient luminance and excellent luminance uniformity even when the light-emitting area is increased. Further, the brightness of each illumination region can be adjusted for high image quality.

The display device preferably includes a control circuit that controls the amount of illumination light of each light source in accordance with each video signal transmitted to the plurality of light emitting sections.

With such a configuration, the light emission intensity can be independently adjusted for each illumination region.

In addition, the control circuit preferably controls the intensity of the illumination light to the display panel by changing a ratio of an illumination period per unit time to a non-illumination period of the illumination device in accordance with a gray scale level of an image displayed on the display panel.

According to the above configuration, the intensity of illumination light per unit time of each illumination region can be adjusted. This enables the emission intensity to be independently adjusted for each illumination region. Therefore, in this case, by controlling the illumination region corresponding to the display region displaying the bright image to have a high luminance of the illumination light and the illumination region corresponding to the display region displaying the dark image to have a low luminance, a display device (liquid crystal display device) capable of displaying an image with an increased dynamic range and a high contrast feeling can be realized.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope shown in the claims are also included in the technical scope of the present invention.

Industrial applicability of the invention

The illumination device of the present invention can be used as a backlight for a display device such as a liquid crystal display device. The illumination device of the present invention is particularly suitable for a backlight of a large-sized liquid crystal display device.

Claims (20)

1. An illumination device, characterized by:

having a plurality of light source units including a light guide plate and a plurality of light sources,

an illumination region for emitting light incident from the light source to the outside and a light guide region for guiding the light incident from the light source to the illumination region are arranged in the light guide plate,

the illumination region is divided into a plurality of light emitting sections by providing a dividing section for limiting the transmission of light in the direction of the optical axis of the light source,

at least one of the light sources is arranged in the light guide region with respect to each of the light emitting parts,

the plurality of light source units are arranged at least in a first direction in which the light emitting sections are arranged in the illumination area,

the dividing portion is also provided in at least a part of the light emitting portions between the light source units adjacent to each other in the first direction.

2. A lighting device as recited in claim 1, wherein:

the width of the dividing portion provided between the light emitting portions in each light source unit is the same as the width of the dividing portion provided between the light source units adjacent in the first direction.

3. A lighting device as recited in claim 1, wherein:

the segments between the light-emitting parts between the light source units adjacent to each other in the first direction are provided at least one end of each light source unit in the first direction, the width of the segments at both ends of each light source unit in the first direction is c1 and c2, the width of the segments provided between the light-emitting parts in each light source unit is b, and c1 is not less than 0, c2 is more than 0, and b is more than 0, the following formula (1) is satisfied

c1+c2＝b……(1)。

4. A lighting device as recited in claim 3, wherein:

c1＝c2＝1/2b。

5. a lighting device as recited in any one of claims 1-4, wherein:

the dividing part is a slit or a groove provided in the light guide plate.

6. A lighting device as recited in any one of claims 1-5, wherein:

the divided portions are layers having a refractive index smaller than that of the light emitting portions divided by the divided portions.

7. A lighting device as recited in any one of claims 1-6, wherein:

the dividing portion satisfies a total reflection condition.

8. A lighting device as recited in any one of claims 1-4, wherein:

the dividing part is formed by a light scattering material or a light shielding body.

9. A lighting device as recited in any one of claims 1-8, wherein:

the divided portion includes, in the illumination region, a point at which light incident from a light source provided with respect to a light emitting portion adjacent in the first direction intersects.

10. A lighting device as recited in any one of claims 1-9, wherein:

the light emitting portions are directly connected to the end portions of the illumination region on the side opposite to the light guide region, respectively, without the partition portions.

11. A lighting device as recited in any one of claims 1-10, wherein:

the dividing portion is provided from one end to the other end of the illumination region.

12. A lighting device as recited in any one of claims 1-11, wherein:

the dividing portion has a concave-convex shape.

13. A lighting device as recited in any one of claims 1-12, wherein:

in the second direction of each of the light source units, the other light source unit is disposed so that the illumination region of the other light source unit overlaps at least a part of the light guide region of the one light source unit.

14. An illumination device, characterized by:

which has a plurality of light source blocks including a light source and a light guide block,

the light guide block has a light emitting portion for emitting light incident from the light source to the outside, and a light guide portion for guiding the light incident from the light source to the light emitting portion,

a plurality of the light source blocks are arranged in the first direction to form a light source unit,

at least a part of the adjacent light guide portions in the light source unit are connected to each other, and an optical dividing portion is provided at least a part of the adjacent light emitting portions,

a plurality of the light source units are arranged at least in the first direction,

the dividing portion is also provided in at least a part of the light emitting portions between the light source units adjacent to each other in the first direction.

15. A lighting device as recited in claim 14, wherein:

each of the light source units includes: a light guide region in which at least a part of adjacent light guide portions are connected to each other; and an illumination region including the light emitting section and the dividing section,

a plurality of the light source units are two-dimensionally arranged adjacent to other light source units in a second direction of the light source units,

at least a part of the light guide region of one light source unit adjacent in the second direction overlaps the illumination region of another light source unit.

16. A display device, comprising:

a display panel; and

the lighting device of any one of claims 1 to 15.

17. The display device of claim 16, wherein:

the light source device has a control circuit that controls the amount of illumination light of each light source in accordance with each video signal sent to the plurality of light emitting sections.

18. The display device of claim 17, wherein:

the control circuit controls the intensity of illumination light to the display panel by changing the ratio of an illumination period per unit time to a non-illumination period of the illumination device in accordance with the gradation level of an image displayed on the display panel.

19. A light guide plate, characterized in that:

an illumination region for emitting light incident from a light source to the outside and a light guide region for guiding the light incident from the light source to the illumination region are arranged,

the illumination region is divided into a plurality of light emitting sections by providing a dividing section for limiting the transmission of light in the direction of the optical axis of the light source,

the dividing portion is also provided in at least a part of at least one end in a first direction in which the light emitting portions of the illumination region are arranged.

20. A light guide plate, characterized in that:

the light guide block includes a light emitting portion for emitting light incident from a light source to the outside, and a light guide portion for guiding the light incident from the light source to the light emitting portion,

a plurality of the light guide blocks are arranged in one dimension,

at least a part of the adjacent light guide portions are connected to each other, and an optical dividing portion is provided at least a part of the adjacent light emitting portions,

the dividing portion is also provided at least in a part of at least one end in the direction in which the light guide blocks are arranged.