WO2012070442A1 - Lighting device and display device - Google Patents

Abstract

A lighting device (3) is provided with a plurality of light sources (4) and a light guide plate (6) wherein the light guide plate (6) has a light entering surface (6a) where light from the light sources (4) enters and an exit surface (6b) where light exits on the side toward an object to be irradiated. A patterned part (30) for which patterning for altering the propagation direction of light has been implemented is provided on the exit surface (6b) or the surface (6c) on the opposite side thereto. A distance (L) between an end part of the patterned part (30) and the light sources (4) and a distance (p) between adjacent light sources satisfy the relationship: p/L <= 2.0. Thus, occurrences of variations in brightness are prevented while suppressing reductions in the brightness of the illuminating light in the lighting device.

Description

Lighting device and display device

The present invention relates to an illuminating device, and more particularly to an illuminating device including a light source and a light guide plate that emits light from the light source to an irradiated object such as a liquid crystal panel, and a display device using the illuminating device.

In recent years, for example, liquid crystal display devices have been widely used in liquid crystal televisions, monitors, mobile phones and the like as flat panel displays having features such as thinness and light weight compared to conventional cathode ray tubes. Such a liquid crystal display device includes an illumination device (backlight) that emits light and a liquid crystal panel that displays a desired image by serving as a shutter for light from a light source provided in the illumination device. It is.

The illumination device is roughly classified into a direct type and an edge light type depending on the arrangement of the light source with respect to the liquid crystal panel as an object to be irradiated with light. For example, mobile devices such as mobile phones, notebook PCs, and PDAs are used. In the liquid crystal display device used, an edge light type that is easy to be thinned compared to a direct type is generally used. That is, in the edge light type illumination device, the light source is arranged on the side of the liquid crystal panel to reduce the thickness, and a light guide plate having a light emitting surface arranged to face the non-display surface of the liquid crystal panel is provided. The light from the light source is applied to the liquid crystal panel.

As the light source, for example, a plurality of point light sources such as LEDs, or a linear light source between cold cathodes is used. When a plurality of point light sources are arranged, brightness unevenness occurs in the vicinity of the incident surface of the light guide plate during lighting. If the luminance is uneven, the display quality is lowered.

In order to eliminate uneven brightness and obtain uniform illumination light, for example, in Patent Document 1 below, a distance d between a plurality of point light source elements arranged along the incident surface of the light guide plate and the incident surface of the light guide plate, It has been proposed that the arrangement interval p of the point light source elements is 0.2 <= d / p <1.

JP 2006-134661 A

However, in the conventional technique described above, in order to suppress the occurrence of luminance unevenness, it is necessary to dispose the light source at a certain distance from the incident surface of the light guide plate. For this reason, the amount of light incident on the light guide plate is reduced, and the luminance of the irradiated light may be lowered. Moreover, since the distance between the light source and the incident surface of the light guide plate is limited, it also hinders narrowing of the frame.

In view of the above problems, the present invention provides an illumination device excellent in light emission quality capable of preventing the occurrence of luminance unevenness while suppressing a decrease in luminance of illumination light, and a display device using the same. With the goal.

An illuminating device disclosed in the present application is an illuminating device including a plurality of light sources arranged side by side and a light guide plate that guides light from the light sources in a predetermined propagation direction and emits the light to an irradiated object side. And
The light guide plate is disposed opposite to the light source, and has a light incident surface that receives light from the light source, and an output surface that emits light to the irradiated object side,
On the exit surface or the facing surface facing the exit surface, a pattern portion is provided that is subjected to patterning for changing the propagation direction of light,
A distance L between the light source side end of the pattern portion and the light source and a distance p between adjacent light sources satisfy the relationship of the following formula (1).

P / L <= 2.0 (1)

As described above, in the illuminating device configured as described above, the distance L between the light source side end of the pattern portion and the light source for changing the light propagation direction in the light guide plate, and the distance p between adjacent light sources. Are arranged so as to satisfy the relationship of p / L <= 2.0. Thereby, it is possible to suppress the occurrence of luminance unevenness without particularly limiting the distance between the incident surface of the light guide plate and the light source. As a result, it is possible to configure an illuminating device excellent in light emission quality that can prevent luminance unevenness from occurring while suppressing a decrease in luminance of illumination light to the irradiated object.

Further, in the illumination device, it is preferable that an end portion on the light source side of the pattern portion is located on the inner side of the light incident surface of the light guide plate.

This makes it possible to bring the light guide plate closer to the incident surface and the light source while suppressing the occurrence of uneven brightness. Therefore, it is possible to further suppress a decrease in luminance of the irradiation light. Further, it is easy to narrow the frame of the lighting device and the display panel using the lighting device.

Also, the light source side end of the pattern portion may be configured to be located on the light incident surface of the light guide plate. As described above, even if the pattern portion 30 is provided to the limit of the light incident surface 6a, an effect of preventing occurrence of uneven brightness can be obtained while suppressing a decrease in brightness of the illumination light to the irradiated object.

The lighting device includes a light source substrate having an attachment surface to which the light source is attached, and the light source is arranged so that the attachment surface of the light source substrate is parallel to the light incident surface of the light guide plate. It can be set as the aspect arrange | positioned facing the light-guide plate. In this case, it is possible to further easily narrow the frame of the lighting device.

Further, the display device of the present invention is characterized by using any one of the lighting devices described above.

In the display device configured as described above, since an illumination device with excellent light emission quality that can prevent uneven brightness in the illumination light to the irradiated object is used, a display with excellent display quality is used. The apparatus can be easily configured.

In the display device, a liquid crystal panel may be used as the irradiated object.

In this case, a liquid crystal display device excellent in display quality can be easily configured.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the illuminating device excellent in the light emission quality which can prevent generation | occurrence | production of brightness nonuniformity, suppressing a brightness | luminance reduction of illumination light, and a display apparatus using the same. .

FIG. 1 is a diagram for explaining an illumination device and a liquid crystal display device according to a first embodiment of the present invention. FIG. 2 is a diagram for explaining the configuration of the liquid crystal panel shown in FIG. FIG. 3 is a plan view illustrating an arrangement example of the light emitting diode, the light guide plate, and the pattern portion. FIG. 4 is an enlarged side view for explaining a main configuration of the lighting apparatus shown in FIG. FIG. 5 is a graph showing the results of examining the unevenness level when p / L is changed. FIG. 6 is an enlarged side view illustrating the configuration of the main part of the illumination device according to the second embodiment of the present invention. FIG. 7: is an enlarged side view explaining the principal part structure of the illuminating device concerning the 3rd Embodiment of this invention. FIG. 8: is an enlarged side view explaining the principal part structure of the illuminating device concerning the 4th Embodiment of this invention. FIG. 9 is a plan view for explaining the arrangement of main parts when the illumination device according to the fifth embodiment of the present invention is viewed from the light emitting surface side.

Hereinafter, preferred embodiments of the illumination device of the present invention and a liquid crystal display device using the same will be described with reference to the drawings. In the following description, the case where the present invention is applied to a transmissive liquid crystal display device will be described as an example. Moreover, the dimension of the structural member in each figure does not faithfully represent the actual dimension of the structural member, the dimensional ratio of each structural member, or the like.

[First Embodiment]
FIG. 1 is a diagram for explaining an illumination device and a liquid crystal display device according to a first embodiment of the present invention. 1, the liquid crystal display device 1 according to the present embodiment includes a liquid crystal panel 2 in which the upper side of FIG. 1 is installed as a viewing side (display surface side), and a non-display surface side of the liquid crystal panel 2 (lower side of FIG. 1). And an illuminating device 3 of the present invention that generates illumination light for illuminating the liquid crystal panel 2. Further, in the liquid crystal display device 1, the liquid crystal panel 2 and the illumination device 3 are assembled to each other, and are integrated as a transmissive liquid crystal display device 1 in which illumination light from the illumination device 3 enters the liquid crystal panel 2. ing.

The liquid crystal panel 2 includes a liquid crystal layer and an active matrix substrate and a color filter substrate as a pair of substrates that sandwich the liquid crystal layer (not shown). In the active matrix substrate, pixel electrodes, thin film transistors (TFTs), etc. (not shown) are formed between the liquid crystal layers in accordance with a plurality of pixels included in the display surface of the liquid crystal panel 2. On the other hand, on the color filter substrate, a color filter, a counter electrode, and the like are formed between the liquid crystal layer (not shown).

Further, the liquid crystal panel 2 is provided with a control device (not shown) that controls the driving of the liquid crystal panel 2, and operates the liquid crystal layer in units of pixels to drive the display surface in units of pixels. A desired image is displayed on the display surface.

The liquid crystal mode and pixel structure of the liquid crystal panel 2 are arbitrary. Moreover, the drive mode of the liquid crystal panel 2 is also arbitrary. That is, as the liquid crystal panel 2, any liquid crystal panel that can display information can be used. Therefore, the detailed structure of the liquid crystal panel 2 is not shown in FIG.

Next, the liquid crystal panel 2 of the present embodiment will be specifically described with reference to FIG.

(LCD panel)
FIG. 2 is a diagram for explaining the configuration of the liquid crystal panel shown in FIG.

2, the liquid crystal display device 1 (FIG. 1) includes a panel control unit 16 that performs drive control of the liquid crystal panel 2 (FIG. 1) as the display unit that displays information such as characters and images, and the panel control. A source driver 17 and a gate driver 18 that operate based on an instruction signal from the unit 16 are provided.

The panel control unit 16 is provided in the control device, and receives a video signal from the outside of the liquid crystal display device 1. In addition, the panel control unit 16 performs predetermined image processing on the input video signal to generate each instruction signal to the source driver 17 and the gate driver 18, and the input video signal. And a frame buffer 16b capable of storing display data for one frame included. Then, the panel control unit 16 controls the driving of the source driver 17 and the gate driver 18 according to the input video signal, so that information corresponding to the video signal is displayed on the liquid crystal panel 2.

The source driver 17 and the gate driver 18 are installed on the active matrix substrate, for example. Specifically, the source driver 17 is installed on the surface of the active matrix substrate so as to extend along the lateral direction of the liquid crystal panel 2 in the outer area of the effective display area A of the liquid crystal panel 2 as a display panel. Further, the gate driver 18 is installed on the surface of the active matrix substrate so as to be along the vertical direction of the liquid crystal panel 2 in the outer region of the effective display region A.

The source driver 17 and the gate driver 18 are drive circuits for driving a plurality of pixels P provided on the liquid crystal panel 2 side by pixel, and the source driver 17 and the gate driver 18 include a plurality of source lines S1 to S1. SM (M is an integer of 2 or more, hereinafter collectively referred to as “S”) and a plurality of gate wirings G1 to GN (N is an integer of 2 or more, hereinafter collectively referred to as “G”). Each is connected. These source wiring S and gate wiring G constitute a data wiring and a scanning wiring, respectively, on a transparent glass material or a transparent synthetic resin substrate (not shown) included in the active matrix substrate. They are arranged in a matrix so as to cross each other. That is, the source wiring S is provided on the substrate so as to be parallel to the matrix-like column direction (vertical direction of the liquid crystal panel 2), and the gate wiring G is arranged in the matrix-like row direction (horizontal of the liquid crystal panel 2). Is provided on the substrate so as to be parallel to (direction).

Further, in the vicinity of the intersection between the source line S and the gate line G, the thin film transistor 19 as a switching element and the pixel P having the pixel electrode 20 connected to the thin film transistor 19 are provided. In each pixel P, the common electrode 21 is configured to face the pixel electrode 20 with the liquid crystal layer provided on the liquid crystal panel 2 interposed therebetween. That is, in the active matrix substrate, the thin film transistor 19, the pixel electrode 20, and the common electrode 21 are provided for each pixel.

In the active matrix substrate, a plurality of pixel P regions are formed in each region partitioned in a matrix by the source wiring S and the gate wiring G. The plurality of pixels P include red (R), green (G), and blue (B) pixels. These RGB pixels are sequentially arranged in this order, for example, in parallel with the gate wirings G1 to GN. Further, these RGB pixels can display corresponding colors by a color filter layer (not shown) provided on the color filter substrate side.

In the active matrix substrate, the gate driver 18 scans a gate signal of the corresponding thin film transistor 19 with respect to the gate wirings G1 to GN (gate signal) based on an instruction signal from the image processing unit 16a. ) Are output sequentially. The source driver 17 also supplies a data signal (voltage signal (gradation voltage)) corresponding to the luminance (gradation) of the display image to the corresponding source wirings S1 to SM based on the instruction signal from the image processing unit 16a. Output.

(Lighting device)
The lighting device 3 shown in FIG. 1 is an example of a so-called edge light module. The illumination device 3 includes a light emitting diode 4 as an example of a light source, an LED substrate 5 as a light source substrate on which the light emitting diode 4 is mounted, and light from the light emitting diode 4 in a predetermined propagation direction (left and right direction in FIG. 1). And a light guide plate 6 for emitting the light on the liquid crystal panel (irradiated object) 2 side. The light guide plate 6 is made of, for example, a synthetic resin such as a transparent acrylic resin having a rectangular cross section. The light guide plate 6 is disposed so as to face the light emitting diode 4, and light from the light emitting diode 4 is used. A light incident surface 6a, a light emitting surface 6b that emits light toward the liquid crystal panel 2, and a facing surface 6c that faces the light emitting surface 6b. In the present embodiment, the light emitting surface 6 b is the exit surface of the light guide plate 6, and the facing surface 6 c is the bottom surface of the light guide plate 6.

In the example shown in FIG. 1, the surface that does not face the light incident surface 6a, that is, the surface perpendicular to the light incident surface 6a is the light emitting surface 6b. In this configuration, it is preferable to change the propagation direction of the light incident on the light guide plate 6 so that as much light as possible is directed to the light emitting surface 6b. As one means for changing the propagation direction of light, for example, patterning can be performed on the facing surface 6c. In the illuminating device 3 shown in FIG. 1, the pattern part 30 which patterned for changing the propagation direction of light is formed in the opposing surface 6c which opposes the light emission surface 6b which is the light emission surface of the light-guide plate 6. As shown in FIG. .

Further, a reflector 8 is provided below the light emitting diode 4 and the light guide plate 6 in the lighting device 3. The reflecting plate 8 reflects light from the light emitting diode 4 and the light guide plate 6. Further, a reflecting plate 9 as a reflecting portion that reflects light from the light emitting diode 4 is also provided on the liquid crystal panel 2 side of the light emitting diode 4.

In the lighting device 3, for example, a diffusion sheet 10, a prism sheet 11, and a reflective polarizing sheet 12 are sequentially provided from the light guide plate 6 side as optical members provided between the light guide plate 6 and the liquid crystal panel 2. ing. By these optical members, the light from the light emitting surface 6b of the light guide plate 6 is changed to the above-mentioned planar illumination light having uniform luminance and is given to the liquid crystal panel 2.

FIG. 3 is a plan view showing an arrangement example of the light emitting diode 4, the light guide plate 6, and the pattern unit 30 when viewed from the liquid crystal panel 2 side. In the example shown in FIG. 3, the plurality of light emitting diodes 4 are arranged along the light incident surface 6 a of the light guide plate 6 at intervals p. Here, the interval p (pitch) is, for example, the distance between the center lines CL of the adjacent light emitting diodes 4. Here, the distance L between the light emitting diode 4 side end of the pattern unit 30 and the light emitting diode 4 and the distance p between the adjacent light emitting diodes 4 satisfy the relationship of the following formula (1).
p / L <= 2.0 ――― (1)

Further, the lighting device 3 includes a bottomed chassis 13 that houses the light emitting diode 4, the light guide plate 6, the diffusion sheet 10, the prism sheet 11, and the reflective polarizing sheet 12, and an L-shaped cross section having an opening. And a bezel 14 which is assembled to the chassis 13 and constitutes an outer container of the lighting device 3 is provided. In the liquid crystal display device 1 of the present embodiment, a P (plastic) chassis 15 is installed on the bezel 14, and the liquid crystal panel 2 is placed on the P chassis 15. 3 are assembled together.

Here, with reference to FIG. 4 as well, the main configuration of the illumination device 3 of the present embodiment will be specifically described.

FIG. 4 is an enlarged side view for explaining a main configuration of the lighting apparatus shown in FIG. In FIG. 4, only the diffusion sheet 10 out of the diffusion sheet 10, the prism sheet 11, and the reflective polarizing sheet 12 as optical members is illustrated and described for the sake of simplification of the drawing (see below). The same applies to FIGS. 6, 7 and 8.)

In FIG. 4, for example, a light emitting diode 4 that emits white light is used. The light emitting diode 4 is disposed to face the light incident surface 6 a of the light guide plate 6. Further, the center line CL of the light emitting diode 4 is arranged in a state where the center line CL in the thickness direction of the light guide plate 6 (vertical direction in FIG. 4) coincides with the center in the same direction. In the lighting device 3, the light emitting diode 4 faces the light guide plate 6 so that the mounting surface (attachment surface to which the light source is attached) 5 a of the LED substrate 5 is parallel to the light incident surface 6 a of the light guide plate 6. Has been placed.

In the lighting device 3, the end surface 10 a on the light emitting diode 4 side of the diffusion sheet 10 is separated from the light incident surface 6 a of the light guide plate 6 by a predetermined distance W2 from the light emitting diode 4 side. Thereby, in the illuminating device 3, it can prevent now that the light from the light emitting diode 4 enters into the inside of the said diffusion sheet 10 directly from the end surface 10a of the diffusion sheet 10. FIG.

Furthermore, the light emitting diode 4 is provided so that the distance L between the light emitting diode 4 side end of the pattern portion 30 and the light emitting diode 4 satisfies the relationship of the above formula (1). The pattern unit 30 is arranged so that the end of the pattern unit 30 on the light emitting diode 4 side is located inside the light incident surface 6 a of the light guide plate 6.

The pattern part 30 can be formed by, for example, printing a paint on the surface of the light guide plate 6, but the patterning method in the pattern part 30 is not limited to a specific one. As patterning, for example, convex portions or concave portions of about 0.01 to 0.09 mm can be distributed on the surface of the light guide plate. As an example, the pattern unit 30 can be formed by printing a paint having a refractive index of 1.0 or more on the surface of the light guide plate 6. Such convex portions or concave portions may be distributed so as to become denser as the distance from the light incident surface 6 a of the light guide plate 6 increases, for example.

By providing such a pattern portion 30 as the facing surface 6c, the direction in which the light propagating through the light guide plate 6 travels after being totally reflected by the pattern portion 30 becomes random, and the light traveling toward the light emitting surface 6b increases. Therefore, the range in which the pattern part 30 is formed affects the light emission range from the light emitting surface 6b. The pattern portion 30 is preferably provided corresponding to the emission range. By appropriately adjusting the distance L between the end portion of the pattern portion 30 and the light emitting diode 4 and the interval p between the light emitting diodes 4 as shown in the above formula (1), the luminance unevenness in the light emitted from the light emitting surface 6b is obtained. It becomes possible to prevent. Further, the distance W 1 between the light incident surface 6 a of the light guide plate 6 and the light emitting diode 4 can be configured to be shorter than the distance L between the end of the pattern portion 30 and the light emitting diode 4. Therefore, the distance between the light incident surface 6a and the light emitting diode 4 can be reduced, and the luminance can be improved and the narrow frame can be facilitated.

In addition, the pattern part 30 may be formed so that the edge part by the side of the light source of the pattern part 30 may be located in the light-incidence surface 6a of the light-guide plate 6. FIG. Thus, even when the pattern portion 30 is formed to the limit of the light incident surface 6a of the light guide plate 6, the distance L between the end portion of the pattern portion 30 and the light emitting diode 4 and the pitch p are set as described above. By setting as described above, it is possible to suppress luminance unevenness and luminance reduction.

As described above, in the present embodiment, in the illumination device 3, it is possible to prevent luminance unevenness from occurring in the illumination light to the liquid crystal panel (object to be irradiated) 2, and to suppress reduction in luminance and narrow frame. . As a result, it is possible to configure the lighting device 3 having excellent light emission quality.

Here, the test result of the verification test conducted by the inventor of the present invention will be specifically described. FIG. 5 is a graph showing the result of examining the unevenness level when the relationship between the distance L between the light incident surface 6a of the light guide plate 6 and the light emitting diode 4 and the interval p between the light emitting diodes 4 is changed. In the graph shown in FIG. 5, the line K indicates the level of unevenness that has passed the subjective evaluation. In the results shown in FIG. 5, when p / L> 2.0, luminance unevenness is seen in the vicinity of the light emitting diode 4 and the display quality is deteriorated. When p / L <= 2.0, the display quality is good. The unevenness level can be evaluated, for example, as follows. In advance, luminance distribution data of those that are considered to have good unevenness levels are collected. When there is no uneven brightness, the brightness position is constant regardless of the location. Then, the brightness distribution data is taken again by changing the LED pitch. By comparing the luminance distribution data with previously acquired luminance distribution data, the unevenness level at the pitch can be evaluated. For example, if the luminance distribution data after the pitch change is not constant compared to the luminance distribution data acquired in advance, it can be determined that the unevenness level is bad.

Moreover, in this embodiment, since the illuminating device 3 excellent in the light emission quality which can prevent generation | occurrence | production of brightness irregularity in the illumination light to the liquid crystal panel (object to be irradiated) 2 is used, the display quality is excellent. The liquid crystal display device 1 can be easily configured.

[Second Embodiment]
FIG. 6 is an enlarged side view illustrating the configuration of the main part of the illumination device according to the second embodiment of the present invention. In FIG. 6, the same members as those in FIG. In FIG. 6, the main difference between the present embodiment and the first embodiment is that the pattern portion 31 is formed by processing the facing surface 6 c of the light guide plate 6. In the example shown in FIG. 6, the pattern portion 31 is a region where fine concave portions are distributed on the facing surface 6 c. Such a pattern part 31 can be formed by laser processing, for example. Alternatively, the light guide plate 6 provided with the pattern portions 31 can also be made by a method in which the light guide plate material is poured into a mold and hardened. Moreover, it can replace with or add to the structure which forms a recessed part in the surface of a light-guide plate as mentioned above, and can also form a convex part.

This embodiment is an example of the case where the pattern portion is formed by providing irregularities on the surface of the light guide plate. Even in such a configuration, the relationship between the distance L between the end portion of the pattern portion 31 and the light emitting diode 4 and the interval p between the light emitting diodes 4 is set to the relationship shown in the above (1). The same effect as the form can be obtained.

[Third Embodiment]
FIG. 7: is an enlarged side view explaining the principal part structure of the illuminating device concerning the 3rd Embodiment of this invention. In FIG. 7, the same members as those in FIG. In FIG. 7, the main difference between the present embodiment and the first embodiment is that the pattern portion 32 is formed of an optical sheet. In the example illustrated in FIG. 7, a prism sheet including an interface having irregularities with respect to the facing surface 6 c is provided as the pattern portion 32 on the facing surface 6 c. The light totally reflected at the interface of the prism sheet changes in the propagation direction at random, so that the light directed toward the light emitting surface 6b increases.

This embodiment is an example where the pattern portion is provided on the bottom surface of the light guide plate. Also in the present embodiment, the relationship between the distance L between the end portion of the pattern portion 32 and the light emitting diode 4 and the interval p between the light emitting diodes 4 is the relationship shown in the above (1), so that the first The same effect as the embodiment can be obtained.

[Fourth Embodiment]
FIG. 8: is an enlarged side view explaining the principal part structure of the illuminating device concerning the 4th Embodiment of this invention. In FIG. 8, the same members as those in FIG. In FIG. 8, the main difference between the present embodiment and the first embodiment is that the pattern portion 33 is provided on the light emitting surface 6b side instead of the facing surface 6c. In the example shown in FIG. 8, a prism sheet including an interface having irregularities with respect to the light emitting surface 6b is provided as the pattern portion 33 on the light emitting surface 6b. The light totally reflected at the interface of the prism sheet changes in the propagation direction at random, so that the light toward the facing portion 6c increases. The light traveling toward the facing surface 6c is reflected by the reflecting sheet 8 and travels toward the light emitting surface 6b. Therefore, as a result, the light toward the light emitting surface 6b increases.

Thus, this embodiment is an example in which the pattern portion is provided on the light exit surface (front surface) of the light guide plate. Also in the present embodiment, the relationship between the distance L between the end portion of the pattern portion 33 and the light emitting diode 4 and the interval p between the light emitting diodes 4 is the relationship shown in the above (1), so that the first The same effect as the embodiment can be obtained.

[Fifth Embodiment]
FIG. 9: is a top view explaining the principal part arrangement | positioning at the time of seeing the illuminating device concerning the 5th Embodiment of this invention from the light emission surface side. In FIG. 9, the same members as those in FIG. In FIG. 9, the main difference between the present embodiment and the first embodiment is that the end of the pattern unit 30 on the light emitting diode 4 side is not linear but formed in a curved shape. That is, when viewed from the light emitting surface side of the light guide plate 6, the end portion of the pattern portion 30 is formed in a shape recessed inward at a position corresponding to the light emitting diode 4. Thus, by forming the end portion of the pattern portion 30 corresponding to the light emitting diode 4, it may be possible to suppress the occurrence of luminance unevenness. In this case, the distance L between the light emitting diode 4 and the end of the pattern unit 30 is defined by, for example, the distance between the end of the pattern unit 30 facing the light emitting diode 4 and the end located closest to the light emitting diode 4. can do. The relationship between the distance L between the end portion of the pattern portion 30 and the light emitting diode 4 and the interval p between the light emitting diodes 4 defined as described above is set to the relationship shown in the above (1). The same effect as the form can be obtained. The method for defining the distance L is not limited to the above example. For example, the average value of the distance between the light emitting diode 4 and the pattern portion may be the distance L.

It should be noted that all of the above embodiments are illustrative and not restrictive. The technical scope of the present invention is defined by the claims, and all modifications within the scope equivalent to the configurations described therein are also included in the technical scope of the present invention.

For example, in the above description, the case where the present invention is applied to a transmissive liquid crystal display device has been described. However, the lighting device of the present invention is not limited to this, and a transflective liquid crystal display device or a liquid crystal display device is not limited thereto. The present invention can be applied to various display devices such as a projection display device using a panel as a light valve.

In addition to the above explanation, the present invention is installed on a light box for illuminating X-ray film or photographic negatives for irradiating light to make it easy to see, or on a signboard or a wall in a station. It can be suitably used as a lighting device for a light emitting device that illuminates advertisements and the like.

In the above description, the light emitting diode is used as the light source. However, the light source of the present invention is not limited to this, and a discharge tube such as a cold cathode fluorescent tube or a hot cathode fluorescent tube is used. You can also

In the above description, the LED substrate (light source substrate) having the mounting surface (mounting surface) is provided, and the light emitting diode (light source) is arranged so that the mounting surface of the LED substrate is parallel to the light incident surface of the light guide plate. The case where it has been arrange | positioned facing the light-guide plate was demonstrated. However, this invention is not limited to this, The structure provided so that the attachment surface of a light source substrate may become a predetermined angle with respect to the light-incidence surface of a light-guide plate may be sufficient.

However, as in each of the above-described embodiments, the case where the light source is arranged facing the light guide plate so that the mounting surface of the light source substrate is parallel to the light incident surface of the light guide plate It is preferable in that the narrow frame can be easily achieved.

In the above description, the configuration in which the pattern portion is provided on the opposing surface 6c of the light guide plate 6 and the configuration in which the pattern portion is provided on the light emitting surface 6b have been described. However, the pattern portion is provided on both the opposing surface 6c and the light emitting surface 6b. May be.

In the above description, the light source is installed so as to face one side surface of the light guide plate. However, the present invention is not limited to this, and the light source is provided on at least one side surface of the light guide plate. What is necessary is just to oppose.

The present invention is useful for an illuminating device excellent in light emission quality capable of preventing unevenness in luminance of illumination light and a display device using the same.

1 Liquid crystal display device 2 Liquid crystal panel (object to be irradiated)
3 Lighting device 4 Light emitting diode (light source)
5 LED board (light source board)
5a Mounting surface (mounting surface)
6 Light guide plate 6a Light incident surface (incident surface)
6b Light emitting surface (outgoing surface)
6c Opposing surface 30, 31, 32, 33 Pattern part

Claims (10)

A lighting device comprising: a plurality of light sources arranged side by side; and a light guide plate that guides light from the light sources in a predetermined propagation direction and emits the light to the irradiated object side,
The light guide plate is disposed opposite to the light source, and has a light incident surface that receives light from the light source, and an output surface that emits light to the irradiated object side,
On the exit surface or the facing surface facing the exit surface, a pattern portion is provided that is subjected to patterning for changing the propagation direction of light,
The distance L between the light source side end of the pattern portion and the light source and the distance p between adjacent light sources satisfy the relationship of the following formula (1).
p / L <= 2.0 ――― (1) The lighting device according to claim 1, wherein an end of the pattern portion on a light source side is positioned inside the light incident surface of the light guide plate. The lighting device according to claim 1, wherein an end of the pattern portion on a light source side is located on the light incident surface of the light guide plate. A light source substrate having a mounting surface to which the light source is mounted;
4. The light source according to claim 1, wherein the light source is disposed to face the light guide plate so that the mounting surface of the light source substrate is parallel to the light incident surface of the light guide plate. Lighting equipment. The lighting device according to any one of claims 1 to 4, wherein the pattern portion is provided on a bottom surface of the light guide plate. 6. The illumination device according to claim 1, wherein the pattern portion is provided on the emission surface of the light guide plate. The lighting device according to any one of claims 1 to 6, wherein the pattern portion is formed by printing a paint having a refractive index of 1.0 or more on a surface of the light guide plate. The lighting device according to any one of claims 1 to 7, wherein the pattern portion is formed by providing irregularities on a surface of the light guide plate. A display device using the illumination device according to any one of claims 1 to 8. The display device according to claim 9, wherein a liquid crystal panel is used as the irradiated object.

Images