JP2008123725A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illuminating device in which luminance unevenness on a light emitting surface when a planar light emission is obtained from a point light source is suppressed.
A light guide body (12) of a lighting device (1) includes a plurality of light introducing portions (17) having an incident surface (15) and a reflective surface (19). The reflecting surface 19 is formed so that at least a part of the light emitted from the light emitting element 11 and incident from the incident surface 15 is incident, and the reflecting surface 19 reflects the incident light and is a virtual one plane perpendicular to the light emitting surface 16. Guide to the light surface 20. The same number of light emitting elements 11 as the light introducing portions 17 are provided. Each light emitting element 11 is provided to face the incident surface 15 of the light introducing portion 17 so that the light emission direction A is inclined with respect to the light guide direction B perpendicular to the light guide surface 20. The plurality of light introducing portions 17 are provided side by side in the X direction parallel to the light guide surface 20. Among the plurality of light introducing portions 17, at least two light introducing portions 17 have an incident surface 15 formed at one end portion in the X direction parallel to the light guide surface 17, and reflecting surfaces extending from one end portion to the other end portion in the X direction. 19 is formed.
[Selection] Figure 1

Description

  The present invention relates to an illumination device for illuminating an object, for example, an illumination device for illuminating a liquid crystal panel included in a liquid crystal display device.

  A liquid crystal display device includes a backlight device as an illumination device that illuminates a liquid crystal display (LCD) panel. As a light source of the backlight device, a cold cathode fluorescent lamp (abbreviated as CCFL) has been used, but instead of CCFL, a light emitting diode (abbreviated as LED) is used. .

  FIG. 14 is a plan view showing a configuration of a conventional illumination device 100. The lighting device 100 of the prior art includes a plurality of LEDs 101 that are light emitting elements. Since the light emission by the LED 101 is a point light emission that emits light radially, the illumination device 100 includes a light guide plate 102 for converting the LED light emitted from each LED 101 into a surface light emission.

  An illumination device using LEDs is required to reduce the number of LEDs in order to keep costs low. When the number of LEDs is reduced, there arises a problem that the luminance is lowered. Further, when the number of LEDs is reduced, the interval between the LEDs 101 is widened. Therefore, as shown in FIG. 3B to be described later, uneven brightness such as the vicinity of the LED 101 is bright and the brightness between the LED 101 and the LED 101 is apt to occur.

  This uneven brightness is caused by a portion where the LED light cannot wrap around between the LEDs 101, and a dark region 103 that is darker than other portions is formed. This dark area 103 becomes an invalid area that cannot contribute to light emission. Since the invalid area cannot be used for illumination, the invalid area is arranged outside the display area of the LCD panel, which becomes an obstacle to downsizing the backlight device.

  In order to suppress this luminance unevenness, in the illumination device 100 of the prior art shown in FIG. 13, for example, the incident surface 107 on which the light of the light guide plate 102 is incident is formed in an uneven shape so that the incident light spreads over a wide angle. Alternatively, a reflection pattern that diffuses light is formed on the back surface of the light guide plate 102 opposite to the light emitting surface 104 that is a surface emitting surface. Of the LED light, light incident at a shallow angle with respect to the incident surface 107 of the light guide plate 102 is easy to be totally reflected. Therefore, as described above, the incident surface 107 is formed in an uneven shape, or a reflection pattern is formed on the back surface. Even if it does, it is difficult to make light wrap around between LED101, and it is difficult to suppress the brightness nonuniformity between LED101 vicinity and the part between LED101.

  Further, the LED 101 is a point light source, and the point light source emits light at an emission angle close to all directions. Therefore, in order to convert to surface emission, a reflection structure corresponding to the emission angle of each light is provided on the light guide plate 102. There is a need. The light guide plate 102 includes light from all directions, such as light from each LED 101 and light reflected by the side wall of the light guide plate 102. Reflection that can realize high-efficiency light emission in consideration of these lights. It is not easy to provide a structure. Further, if such a structure is provided, a portion used for suppressing luminance unevenness does not contribute to surface light emission, and therefore the light guide plate 102 as a whole loses in terms of light emission efficiency. As described above, the conventional technique has a problem that it is not easy to improve the luminance of the light emitting surface 104 for surface emission.

  As a technique for suppressing unevenness in brightness, a reflective surface is formed at one end of the light guide plate, light is emitted from two light sources toward the reflective surface, and light from the light source is reflected by the reflective surface to emit light. (For example, refer to Patent Documents 1 and 2). In the techniques disclosed in Patent Documents 1 and 2, a continuous reflecting surface is formed over the entire end portion of the light guide plate, and light from the light source is reflected by this reflecting surface, so it is difficult to define the direction of the light. As described above, there is a problem that it is difficult to provide a reflecting structure for converting to surface emission. Further, when the number of light sources is two as in the techniques disclosed in Patent Documents 1 and 2, there is a problem that the luminance is lowered when the light emitting surface size is increased.

  As another technique, light from a point light source is separated into P-polarized light and S-polarized light by a polarization separation plate, and then converted to S-polarized light. There is a technique for making light incident on a light guide plate (see, for example, Patent Document 3). In the technique disclosed in Patent Document 3, it is necessary to provide a polarization separation plate, and there is a problem that the configuration becomes complicated. In addition, since the plurality of point light sources are provided so as to protrude from the polarization separation plate to the side opposite to the light guide plate, there is a problem that the outer dimensions of the illumination device are increased.

JP 2005-339940 A JP 2004-214204 A JP 2003-331626 A

  The objective of this invention is providing the illuminating device with which the brightness nonuniformity in the light emission surface when obtaining planar light emission from a point light source was suppressed.

  Another object of the present invention is to provide an illuminating device that can more reliably define the direction of light guided to a surface emitting portion and can easily increase luminance.

The present invention relates to a point light source that emits light radially, a light-transmitting incident surface on which light emitted from the point light source is incident, and light that is formed substantially perpendicular to the incident surface and incident from the incident surface is emitted. A lighting device comprising a light guide having an outgoing surface,
The light guide is
A plurality of light introducing portions having the incident surface and a reflective surface that is formed so that at least part of light incident from the incident surface is incident and reflects the incident light to a virtual plane that is perpendicular to the emission surface Including
The point light source includes the same number of point light sources as the light introduction part,
Each point light source is provided to face the incident surface of the light introducing portion so that the light emission direction is inclined with respect to the light guide direction perpendicular to the virtual plane.
The plurality of light introducing portions are provided side by side in a direction parallel to the virtual plane.
Among the plurality of light introducing portions, at least two light introducing portions have an incident surface formed at one end portion in a direction parallel to the virtual one plane and extend from one end portion to the other end portion in a direction parallel to the virtual one plane. The illumination device is characterized in that a reflective surface is formed.

  In the invention, it is preferable that each point light source is provided so that the light emission direction is perpendicular to the light guide direction.

  Further, the present invention is characterized in that each point light source is provided such that an angle formed between the light emission direction and the light guide direction is more than 90 ° and less than 180 °.

Further, the invention is characterized in that the reflection surface is formed in an uneven shape.
In the invention, it is preferable that the reflection surface is composed of at least one of a flat portion formed in a flat shape and a curved portion formed in a curved shape.

  In the invention, it is preferable that the reflecting surface has a light emitting portion that emits light by light emitted from a point light source.

In the present invention, the light introducing portion is
Refraction of at least one of the exit surface portion where the exit surface is formed and the entrance surface portion where the entrance surface is formed between the exit surface from which the light from the point light source is emitted and the entrance surface of the light introducing portion Or a coupling portion having a refractive index equal to the refractive index or between the refractive index of the exit surface portion and the refractive index of the entrance surface portion.

  In the invention, it is preferable that the light guide has another reflecting surface that reflects the light emitted from the point light source or the light reflected by the reflecting surface to guide the light to the virtual plane.

  According to the present invention, the light guide including a plurality of light introducing portions and the same number of point light sources as the light introducing portions are provided. Each light introducing section is configured to reflect at least a part of light emitted from the point light source and incident from the incident surface by the reflecting surface and guide it to a virtual plane perpendicular to the emitting surface. The point light source is provided such that the light emission direction is inclined with respect to the light guide direction perpendicular to the virtual plane, and the light emitted from the point light source is reflected by the reflecting surface and is reflected in the virtual one direction. Since the light emitted in the direction parallel to the light guide direction reaches the virtual one plane as it is, the light emitted from the point light source is directed in the direction parallel to the virtual one plane. Can be extended and guided to a wider range. A plurality of light introducing portions are provided side by side in a direction parallel to the virtual one plane. This can suppress uneven luminance between the vicinity of the point light source and the portion between the two adjacent point light sources, so that uneven luminance on the exit surface can be suppressed. Therefore, for example, when the illuminating device is used as an illuminating device that illuminates the liquid crystal display panel of the liquid crystal display device, the portion to be disposed outside the display area of the liquid crystal display panel can be reduced. In addition, the liquid crystal display device can be miniaturized.

  In addition, since it is possible to define the incident direction of light on the virtual one plane by the reflection surface of each light introducing portion, for example, it is possible to make light incident from a specific direction on the virtual one plane. Become. In addition, since at least two of the plurality of light introducing portions have an incident surface at one end in a direction parallel to the virtual plane and a reflecting surface from one end to the other end. The directions of light reflected by the reflecting surfaces of these light introducing portions can be made uniform. As a result, for example, when a reflection structure for guiding light guided to the virtual plane to the output surface is formed on the light guide, a reflection structure capable of guiding light to the output surface with high efficiency is easily provided. be able to. Therefore, the brightness on the exit surface can be easily increased.

  According to the present invention, each point light source is provided such that the light emission direction is perpendicular to the light guide direction. This suppresses uneven brightness between the point light sources, suppresses uneven brightness on the exit surface, and makes the light incident on the reflective surface without excessively increasing the size of the light guide in the light guide direction, The direction of light can be defined. Therefore, the increase in size of the lighting device can be suppressed.

  Further, according to the present invention, each point light source is provided so that the angle formed between the light emission direction and the light guide direction is more than 90 ° and less than 180 °. Compared with the case where the angle formed by is 90 ° or less, more light can be incident on the reflecting surface. As a result, the direction of more light can be defined by the reflecting surface, so that, for example, more light can be incident on the virtual plane from the same direction. Therefore, since a reflection structure for guiding light to the exit surface can be provided more easily, the luminance on the exit surface can be increased more easily.

  According to the invention, the light emitted from the point light source is reflected by the uneven reflecting surface. As a result, the incident light can be diffused on the reflecting surface, so that the luminance unevenness between the portion of the point light source and the portion between the point light sources in the direction parallel to the virtual plane is further suppressed, and the exit surface The brightness unevenness in can be further suppressed.

  According to the invention, the reflecting surface is composed of at least one of a flat surface portion and a curved surface portion. This makes it possible to easily realize a suitable reflecting surface according to the characteristics of the light emitted from the point light source, such as directivity.

  According to the invention, since the reflecting surface has the light emitting portion, the light emitting portion can be caused to emit light by the light emitted from the point light source, and the light emitted from the light emitting portion can be guided to the virtual plane. Therefore, for example, when there is chromaticity variation in the light emitted from the point light source, by appropriately selecting the emission color from the light emitting part, the influence of the chromaticity variation is suppressed, and the chromaticity on the emission surface is reduced. Variation can be suppressed.

  According to the invention, the light introducing portion is at least one of the emitting surface portion of the point light source and the incident surface portion of the light introducing portion between the emitting surface of the point light source and the incident surface of the light introducing portion. A coupling portion having a refractive index equal to one of the refractive indexes or between the refractive index of the exit surface portion of the point light source and the refractive index of the incident surface portion of the light introducing portion is provided. Thereby, the reflectance of light at the interface between the exit surface of the point light source and the incident surface of the light introducing portion can be reduced, so that the coupling efficiency between the point light source and the light introducing portion can be increased. Accordingly, since more light can be incident from the point light source to the light introducing portion, the luminance on the exit surface of the light guide can be further increased.

  According to the invention, since the light guide has another reflecting surface, at least a part of the light emitted from the point light source is reflected by the reflecting surface and guided to the virtual one plane, and the remaining light is reflected. At least a part of the light can be reflected by another reflecting surface and guided to the virtual plane. As a result, more light emitted from the point light source can be guided to the virtual plane, and the luminance on the exit surface can be further increased.

  FIG. 1 is a plan view showing a configuration of a lighting device 1 according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a cross-sectional configuration of the lighting device 1 taken along a section line S2-S2 shown in FIG. It is. FIG. 2 shows a state in which the illumination device 1 is provided in the liquid crystal display device 2.

  The illumination device 1 is a device for illuminating an object with illumination light, and is used, for example, as an edge light type backlight device provided in the transmissive liquid crystal display device 2 shown in FIG. The illuminating device 1 is provided opposite to a liquid crystal display (abbreviated as LCD) panel 3 of the liquid crystal display device 2, and the LCD panel that is the object from the side opposite to the side on which the operator of the liquid crystal display device 2 views the display screen. Illuminate 3. The lighting device 1 includes a light emitting element 11 that is a point light source and a light guide 12. The light guide 12 includes a light guide plate 13 that is a light guide body and a reflective layer 14.

  The light-emitting element 11 that is a point light source (hereinafter sometimes simply referred to as “light source”) emits light, which is illumination light, radially based on electric power provided by a power source (not shown). The light emitting element 11 is realized by, for example, a light emitting diode (abbreviated as LED).

  The light guide plate 13 has a flat plate shape in the present embodiment, and has a substantially rectangular cross section in a virtual plane perpendicular to the thickness direction, more specifically, a substantially rectangular shape. In this embodiment, the light guide plate 13 has a parallel plate shape, and the surfaces on both sides in the thickness direction are formed in planes parallel to each other. The light guide plate 13 has translucency, an incident surface 15 on which light emitted from the light emitting element 11 is incident, and an emission surface that is formed substantially perpendicular to the incident surface 15 and from which light incident from the incident surface 15 is emitted. It has the light emission surface 16 which is. “Substantially vertical” includes “vertical”. The light emitting surface 16 is a surface on one side in the thickness direction of the light guide plate 13. In the present embodiment, the shape of the light guide plate 13 is a parallel plate shape in which the surfaces on both sides in the thickness direction are parallel to each other. However, the shape is not limited to this, and the surface on one side in the thickness direction is the surface on the other side in the thickness direction. It may be a wedge shape that is inclined with respect to the shape, or a shape in which a parallel plate and a wedge are combined.

  The light guide plate 13 is made of translucent resin such as acrylic resin and polycarbonate resin. When the light guide plate 13 is made of acrylic resin or polycarbonate resin, the refractive index of the light guide plate 13 is about 1.49 to 1.59.

  A direction parallel to the thickness direction of the light guide plate 13 is defined as the Z direction, a direction perpendicular to the Z direction and parallel to the short direction of the light guide plate 13 is defined as the X direction, and perpendicular to the Z direction and the X direction. The direction parallel to the longitudinal direction of the light guide plate 13 is defined as the Y direction. In each figure, these X, Y, and Z directions are represented by arrows X, Y, and Z. In the example of FIG. 1, the thickness direction Z is a direction perpendicular to the paper surface.

  As shown in FIG. 2, the light guide 12 is parallel to the LCD panel 3 in the Z direction with the light emitting surface 16, which is the surface on one side in the Z direction, facing the LCD panel 3. Be placed. In the present embodiment, the light guide 12 is uniformly formed in the Z direction, and the surfaces on both sides in the X direction and the Y direction of the light guide 12 are perpendicular to the surfaces 16 and 24 on both sides in the Z direction. is there.

  Light emitted from the light emitting element 11 enters the light guide 12 through one end in the Y direction, which is one end in the longitudinal direction of the light guide 12. A light introducing portion 17 is constituted by one end portion of the light guide 12 in the Y direction. A portion closer to the other end in the Y direction than the light introducing portion 17 of the light guide 12 constitutes a surface light emitting portion 18. The light guide 12 includes a light introducing part 17 and a surface light emitting part 18. The light emitting surface 16 is configured by the surface on one side in the Z direction of the surface light emitting unit 18 and the light introducing unit 17.

  A planar incident surface 15 and a reflective surface 19 are formed at one end in the Y direction of the light guide 12 constituting the light introducing portion 17. The incident surface 15 constitutes a part of an end surface on one side in the X direction (hereinafter also referred to as “one end surface in the X direction”) which is an end surface on one side in the short direction of the light guide 12. The light emitting element 11 which is a light source is provided so that the light emitting surface thereof is parallel to the incident surface 15.

  The reflection surface 19 is formed so that at least a part of the light incident from the incident surface 15 is incident, reflects the incident light, and is a virtual plane (hereinafter referred to as “light guide”) perpendicular to the light emitting surface 16 that is the emission surface. Lead to 20). In the present embodiment, the light guide surface 20 is a virtual plane parallel to the X direction and is perpendicular to the Y direction and the Z direction.

  The reflection surface 19 is a flat surface that is continuous with the incident surface 15 and is inclined from the surface perpendicular to the one end surface in the X direction of the light guide 12 to the other side in the Y direction. The cross-sectional area parallel to the end surface is formed to be small. In the present embodiment, the light guide plate 13 of the light introducing portion 17 has a triangular prism shape in which a triangle disposed on a plane perpendicular to the Z direction, more specifically a right triangle, extends along the Z direction.

  The angle α1 formed by the reflecting surface 19 and the incident surface 15 is selected, for example, from 45 ° to 67.5 °. The angle α1 formed between the reflecting surface 19 and the incident surface 15 is not limited to this. In the cross section perpendicular to the Z direction, the ratio (D2 / D1) of the dimension D1 of the reflecting surface 19 to the dimension D1 of the incident surface 15 is selected from 2 to 5. The ratio D2 / D1 is not limited to this. In the present embodiment, the reflection surface 19 is formed to be inclined between two adjacent light emitting elements 11. The reflection surface 19 is perpendicular to the emission surface 11 a of the light emitting element 11 and the opposite surface in the light introduction portion 17 other than the light introduction portion 17 provided with the light emitting element 11 facing the one end surface in the X direction of the light guide plate 13. It is also formed between one side surface and the light guide plate 13. The dimension D1 of the reflection surface 19 is a reflection surface formed from the emission surface 11a of one light-emitting element 11 to the surface opposite to the emission surface 11a of the other light-emitting element 11 among the two adjacent light-emitting elements 11. 19 dimensions.

  The reflection surface 19 is formed by providing the reflection layer 14 on the surface portion on one side in the Y direction of the light guide plate 13, and more specifically, is an interface between the light guide plate 13 and the reflection layer 14. The reflective layer 14 is formed so as to have a reflectance close to about 1.0 with respect to light incident on the reflective surface 19. As the material of the reflective layer 14, a material having high light reflectivity and a reflectivity close to 1.0 is used. Examples of such a material include silver (Ag) and aluminum (Al).

  A plurality of light introducing portions 17 are provided in the present embodiment. The light introduction unit 17 is provided side by side in the X direction, which is a direction parallel to the light guide surface 20. More specifically, the light introduction part 17 is provided continuously in the X direction.

  Among the plurality of light introducing portions 17, at least two light introducing portions 17 have an incident surface 15 formed at one end portion in a direction parallel to the light guide surface 20, that is, one end portion in the X direction, and are parallel to the light guide surface 20. A reflection surface 19 is formed from one end to the other end in the direction, that is, from one end to the other end in the X direction. In this embodiment, all the light introduction parts 17 have the incident surface 15 formed at one end in the X direction, and the reflection surface 19 formed from one end to the other end in the X direction.

  The same number of light emitting elements 11 as the light introducing portions 17 are provided. These light emitting elements 11 are provided side by side in the X direction parallel to the short direction which is the width direction of the light guide plate 13. Each light emitting element 11 is provided to face the incident surface 15 of the light introducing portion 17 so that the light emission direction is inclined with respect to the light guide direction which is a direction perpendicular to the light guide surface 20. In the present embodiment, each light emitting element 11 is provided such that the light emission direction is perpendicular to the light guide direction. The “light emission direction” is a direction in which light having the maximum intensity is emitted among the directions in which light is emitted from the light source.

  Although not shown, a reflective sheet is provided on the surface portion on the other side in the Z direction (hereinafter also referred to as “the other surface portion in the Z direction”), which is the surface portion opposite to the surface portion facing the LCD panel 3 of the light guide plate 13. Is provided. More specifically, the reflection sheet is provided in a portion closer to the other end in the longitudinal direction than the light guide surface 20 in the other surface portion in the Z direction of the light guide plate 13.

  The reflection sheet is formed so as to reflect the light emitted from the light emitting element 11 and guided to the light guide surface 20 and guide it to one surface in the Z direction, which is the light emitting surface 16 of the light guide plate 13. The reflection sheet is formed on the other surface portion in the Z direction of the light guide plate 13 by printing, for example. Instead of providing a reflection sheet on the other surface portion of the light guide plate 13 in the Z direction, a concavo-convex structure is formed on the other surface portion of the light guide plate 13, and light is guided to the light emitting surface 16 by reflection by the concavo-convex portion. Also good.

  Of the one surface portion of the light guide plate 13 in the Z direction, a diffusion sheet is provided in a portion where the light emitting surface 16 is formed, but the light guided to the light emitting surface 16 is diffused by this diffusion sheet. And emitted from the light emitting surface 16.

  According to the illuminating device 1, the light emitted from the light emitting element 11 enters the light introducing portion 17 of the light guide plate 13 from the incident surface 15, enters the reflective surface 19, is reflected by the reflective surface 19, and is guided to the light guide surface. 20 leads. The light emitted from the light emitting element 11 is incident on each portion of the reflection surface 19 in the X direction according to the emission direction, reflected, and guided to the light guide surface 20. The light emitted radially from the light emitting element 11 is reflected by each portion of the reflecting surface 19 in the X direction, and spreads in the X direction, and is converted into linear light that extends in the X direction, that is, linear light. Accordingly, light can be incident on the surface light emitting portion 18 of the light guide plate 13 from the entire X direction at one end portion in the Y direction of the light guide plate 13.

  FIG. 3 is a diagram showing a comparison between the light emission state in the illumination device 1 of the present embodiment and the light emission state in the conventional illumination device 100. FIG. 3A shows a light emission state in the illumination device 1 of the present embodiment, and FIG. 3B shows a light emission state in the conventional illumination device 100 shown in FIG.

  When the LED 101 which is a light emitting element is arranged so as to emit light in the Y direction parallel to the light guide direction as in the prior art shown in FIG. 3B, the light guide plate 102 in the vicinity of the LED 101 has a Z direction. When viewed from one side, there is a dark area 103 that is darker and lower in brightness than the other areas, resulting in uneven brightness. The dark region 103 is a region indicated by hatching in FIG. 3B and is generated near the portion between the LED 101 and the LED 101. Therefore, the luminance of the portion between the LEDs 101 is lower than the luminance of the portion of the LED 101, and uneven luminance occurs between the portion of the LED 101 and the portion between the LEDs 101, and thus uneven luminance occurs on the light emitting surface 104.

  Since the dark area 103 is an ineffective area that cannot contribute to the light emission on the light emitting surface 104, a portion where the dark area 103 is formed and uneven brightness is not used for illumination, and is a portion outside the display area of the LCD panel. Placed in. In addition, since the portion where the LED 101 is provided is not directly used for illumination, it is disposed outside the display area of the LCD panel. Therefore, in the illumination device 100 shown in FIG. 3B, the portion where the dark region 103 is generated and the portion where the LED 101 is provided are the portions (hereinafter, “ 105).

  In the present embodiment, a plurality of light introducing portions 17 are provided, and light emitted from the light emitting element 11 in each light introducing portion 17 is reflected by the reflecting surface 19 of the light introducing portion 17 to be the light guide surface 20. Led to. The light emitting element 11 is provided such that the light emission direction is inclined with respect to one side in the Y direction which is a light guide direction perpendicular to the light guide surface 20, and the light emitted from the light emitting element 11 reflects the reflection surface 19. And is guided to the light guide surface 20. As a result, as shown in FIG. 3B, the LED 101 as the light source is provided so that the light emission direction is parallel to the light guide direction, and the light emitted in the direction parallel to the light guide direction is guided as it is. Compared with the case of being guided to the light surface 106, the light emitted from the light emitting element 11 can be guided to spread over a wider range in the direction parallel to the light guide surface 20.

  This makes it possible to reduce the dimension in the Y direction perpendicular to the light guide surface 20 of the dark area 22 indicated by hatching, compared with the prior art illumination device 100 shown in FIG. The luminance unevenness between the light emitting element 11 and the portion between the two adjacent light emitting elements 11 can be suppressed, and the luminance unevenness on the light emitting surface 16 can be suppressed. Therefore, the dimension L1 in the Y direction perpendicular to the light guide surface 20 of the display outer portion 23, which is a portion to be disposed in the portion 3b outside the display area 3a of the LCD panel 3 shown in FIG. 2, is shown in FIG. It can be made smaller than the dimension L0 in the Y direction of the outer display portion 105 of the prior art illumination device 100 shown in FIG. Thereby, the illuminating device 1 can be reduced in size.

  Further, in the present embodiment, the light incident direction to the light guide surface 20 can be defined by the reflection surface 19 of each light introducing portion 17, so that light from a specific direction with respect to the light guide surface 20 can be defined. Can be made incident. Accordingly, when a reflection structure for guiding light guided to the light guide surface 20 to the light emitting surface 16 is formed on the light guide plate 13, for example, the back surface 24 opposite to the light emitting surface 16 of the light guide plate 13, Can be easily provided on the back surface 24 that can guide the light to the light emitting surface 16 with high efficiency. Therefore, the luminance on the light emitting surface 16 can be easily increased.

  In particular, in the present embodiment, a plurality of light introduction portions 17 are provided side by side in the X direction, which is a direction parallel to the light guide surface 20, and among these, at least two light introduction portions 17 are provided on the light guide surface 20. An incident surface 15 is formed at one end in the parallel X direction, and a reflecting surface 19 is formed from one end to the other end in the X direction. That is, in these light introducing portions 17, the light emitting elements 11 are provided so that the light emission directions are the same.

  As described above, in the present embodiment, at least two light introducing portions 17 are formed with the incident surface 15 at one end portion in the X direction parallel to the light guide surface 20, and the reflecting surface extends from one end portion to the other end portion in the X direction. Since 19 is formed, the direction of the light reflected by the reflection surface 19 of these light introduction parts 17 can be made uniform. Therefore, since the reflection structure capable of guiding light to the light emitting surface 16 with high efficiency can be easily provided on the back surface 24 of the light guide plate 13, the luminance on the light emitting surface 16 can be more easily increased.

  In the present embodiment, when the light emitting surface size is increased, the number of light emitting elements 11 can be increased according to the size, and necessary surface luminance can be ensured. For example, by increasing the number of light emitting elements 11 from two to three, or from three to four, it is possible to suppress a decrease in luminance due to an increase in the size of the light emitting surface.

  In the present embodiment, the light emission direction from each light emitting element 11 is parallel to the X direction, and each light emitting element 11 is provided so that the light emission direction is perpendicular to the Y direction, which is the light guide direction. ing. That is, the light emitting element 11 is provided such that the light emitting surface thereof is parallel to one side surface of the light guide plate 13. Accordingly, the light emitted from the light emitting element 11 can be reflected by the reflecting surface 19 and guided to the light guiding surface 20 without increasing the dimension in the Y direction which is the longitudinal direction of the light guiding plate 13. Therefore, in the present embodiment, as described above, uneven luminance between the light emitting element 11 and the light emitting element 11 is suppressed, uneven luminance on the light emitting surface 16 of the light guide 12 is suppressed, and the light guide 12 in the light guide direction is suppressed. The direction of the light can be defined by making light incident on the reflecting surface 19 without excessively increasing the size of the light. Therefore, the enlargement of the lighting device 1 can be suppressed.

  In the present embodiment, the ratio D2 / D1 of the dimension D1 of the reflecting surface 19 to the dimension D1 of the incident surface 15 in the cross section perpendicular to the Z direction is selected from 2 to 5. The ratio D2 / D1 is not limited to this, but is preferably 2 or more and 5 or less as in the present embodiment. By setting the ratio D2 / D1 to be 2 or more and 5 or less, the light emitted from the light emitting element 11 is converted to light containing a relatively large amount of light substantially perpendicular to the light guide surface 20 by reflection on the reflection surface 19. Can do. Thus, since the direction of the light reflected by the reflecting surface 19 can be made uniform, the light guide plate 13 can easily provide a reflecting structure capable of guiding light to the light emitting surface 16 with high efficiency. Therefore, the luminance on the light emitting surface 16 can be increased more easily.

  In the present embodiment, the plurality of light emitting elements 11 have uniform dimensions, and are arranged side by side in the X direction so that the positions in the Y direction of the emission surface 11a and one side surface perpendicular to the opposite surface are the same. Therefore, when the ratio D2 / D1 is less than 2, the reflection angle of the reflection surface 19 with respect to the light emitted from the light emitting element 11 increases, and the reflection is guided in a direction having an angle with respect to the light guide surface 20. The proportion of light increases. Specifically, the ratio of the light reflected toward the one end surface in the X direction of the light guide plate 13 increases. When the ratio D2 / D1 exceeds 5, the incident angle of the light emitted from the light emitting element 11 with respect to the reflecting surface 19 becomes small, and also in this case, the incident angle with respect to the light guide surface 20 has an inclination. The proportion of light increases. Specifically, the ratio of light reflected toward the other end surface in the X direction of the light guide plate 13 increases. Therefore, the ratio D2 / D1 is preferably 2 or more and 5 or less.

  Moreover, in this embodiment, the reflective layer 14 is provided between the surface facing the light guide plate 13 among the side surfaces of the light emitting element 11 and the light guide plate 13, and the reflective surface 19 is formed. The light reflected by the portion can be further reflected and guided to the surface light emitting unit 18. In the present embodiment, since the reflecting surface 19 is formed in a flat shape as described above, the light reflected by the reflecting surface 19 is inclined at an inclination angle other than 90 ° with respect to the light guide surface 20. The light reflected by the reflecting surface 19 is light that spreads to some extent in the X direction. Thus, the ratio of the light reflected toward the reflection surface 19 between the one side surface of the light emitting element 11 facing the light guide plate 13 and the light guide plate 13 is reflected by spreading the light to some extent in the X direction. Since more light can be guided to the surface light emitting unit 18, the luminance on the light emitting surface 16 can be increased.

  In the present embodiment, a diffusion sheet is provided in a portion where the light emitting surface 16 of the light guide plate 13 is formed. Instead of the diffusion sheet, a prism sheet may be provided in a portion where the light emitting surface 16 of the light guide plate 13 is formed. By providing the diffusion sheet or the prism sheet, it is possible to suppress variations in luminance on the light emitting surface 16 and further increase the luminance. Moreover, since light can be diffused also in the part between the parts in which the light emitting element 11 of the light-guide plate 13 is provided seeing from the Z direction one side, the part in which the light emitting element 11 is provided, and the light emitting element 11 are provided. The luminance unevenness between the portions can be further suppressed, and the luminance unevenness in the vicinity of the light emitting element 11 on the light emitting surface 16 can be further suppressed.

  In the present embodiment, three light introducing portions 17 are provided, but the number of light introducing portions 17 is not limited to three, and may be four or more.

  FIG. 4 is a plan view showing the configuration of the illumination device 30 according to the second embodiment of the present invention. In the illuminating device 30 of this embodiment, since the configuration other than the light introduction unit 27 of the illuminating device 1 of the first embodiment is the same, the same configuration is denoted by the same reference numeral and described. Is omitted.

  In the light introducing portion 31 of the present embodiment, the light emitting element 11 has a light emission direction indicated by an arrow A and a light guide direction indicated by an arrow B in a cross section perpendicular to the Z direction. The angle θ formed is greater than 0 ° and less than 90 °. Therefore, the emission surface 11a of the light emitting element 11 is inclined with respect to a virtual plane parallel to the light guide surface 20 when viewed from one side in the Z direction, and an angle β formed with the virtual plane is an acute angle, that is, 0 °. <Β <90 ° is satisfied.

  Since the light emitting element 11 is provided so that the emission surface 11 a thereof is parallel to the incident surface 33 of the light introducing portion 31, in this embodiment, the incident surface 33 of the light introducing portion 31 is parallel to the light guide surface 20. It is inclined at an acute angle with respect to a virtual plane, that is, with an inclination angle exceeding 0 ° and less than 90 °. More specifically, the incident surface 33 of the light introducing portion 31 is perpendicular to the light emitting surface 16 of the light guide plate 13 which is the surface on one side of the light guide plate 13 in the Z direction, in this embodiment, the surfaces on both sides in the Z direction of the light guide plate 13. And is inclined at an acute angle with respect to a virtual plane parallel to the light guide surface 20.

  The incident surface 33 of the light introducing portion 31 is a flat surface that is continuous with the one end surface 13a in the X direction that is one end surface perpendicular to the Y direction of the light guide plate 13, and is inclined from the one end surface 13a in the X direction toward the other side in the X direction. The reflecting surface 34 is a plane that is continuous with the incident surface 33 and is inclined to the other side in the Y direction from a virtual plane that includes a line of intersection with the incident surface 33 and is parallel to the X direction. The incident surface 33 and the reflection surface 34 are arranged such that the cross-sectional area of the light guide plate 13 parallel to the virtual plane increases as the distance from the virtual plane parallel to the X direction including the intersection line of the incident surface 33 and the reflection surface 34 increases. It is formed.

  In the light introducing portion 31 of this embodiment, the angle θ formed by the emission direction A and the light guide direction B of the light emitting element 11 exceeds 0 ° and is less than 90 °, that is, satisfies 0 ° <θ <90 °, and has an acute angle. The angle β between the incident surface 33 of the light guide plate 13 and the virtual plane parallel to the light guide surface 20 is 0 ° <β <90 °, which is an acute angle. Accordingly, since the dimension L2 in the Y direction of the outer display portion 35 can be reduced as compared with the light introducing portion 17 in the first embodiment, the lighting device 30 can be further downsized. Here, the angle between the light emission direction A and the light guide direction B from the light emitting element as the light source is that the light emission direction A and the light guide direction B from the light guide direction B toward the reflection surface 19 are as follows. It is the angle that is formed.

  In addition, the directivity characteristics of the light emitting element 11 include, in Far Field Pattern (abbreviated as FFP) measurement, a light output peak in a direction perpendicular to the front surface, that is, the emission surface 11a, and a certain degree to the left and right from the direction perpendicular to the emission surface 11a. That is, there are those having peaks in the positive angle region and the negative angle region in the FFP measurement. In the present embodiment, the amount of light incident on the reflecting surface 34 out of the light emitted from the light emitting element 11 is smaller than that of the light introducing section 17 in the first embodiment. When the light output peak is used, the uniformity of the light incident direction on the light guide surface 20 is inferior. When the light emitting element 11 having such directivity is used, in order to make the incident direction of the light incident on the light guide surface 20 uniform, the light introducing unit causes as much light as possible to enter the reflecting surface. It is preferable to be formed.

  When a light emitting element 11 having a certain angle to the left and right from the direction perpendicular to the emitting surface 11a, for example, having a peak at ± 30 ° is used, the emitting direction of the light emitting element 11 as in this embodiment. It is preferable to use the light introducing portion 31 provided with the light emitting element 11 so that the angle θ formed by A and the light guide direction B exceeds 0 ° and is less than 90 °. In this case, of the light emitted from the light emitting element 11, the light belonging to one peak is directly incident on the light guide surface 20 in a shape that is nearly perpendicular, and the light belonging to the other peak is reflected by the reflecting surface 19 and guided. Since the light is incident on the light surface 20 in a shape that is nearly perpendicular, an effect that the light incident direction on the light guide surface 20 can be made uniform can be obtained.

  FIG. 5 is a plan view showing the configuration of the illumination device 40 according to the third embodiment of the present invention. In the illuminating device 40 of this Embodiment, since the structure of those other than the light introducing | transducing part 17 of the illuminating device 1 of 1st Embodiment is the same, the same referential mark is attached | subjected to the same structure and description. Is omitted.

  In the present embodiment, the reflecting surface 42 of the light introducing portion 41 is connected to the incident surface 15 and has a flat surface portion 42a whose surface is formed in a flat shape, and a curved surface whose surface is connected to the flat surface portion 42a and whose surface is formed in a curved surface shape. Part 42b. The plane portion 42 a is a plane that continues to the incident surface 15 and is orthogonal to the incident surface 15. The curved surface portion 42b is a curved surface that continues to the flat surface portion 42b and curves from the flat surface portion 42b to the other side in the Y direction. The curved surface portion 42b is formed so that a cross-sectional area parallel to the flat surface portion 42b of the light guide plate 13 increases as the distance from the flat surface portion 42a increases.

  In the light introducing portion 41 of the present embodiment, the reflecting surface 42 includes a curved surface portion 42b. Since the curved surface portion 42b is formed in a curved surface shape, more specifically, in a concave curved surface shape, the entire reflecting surface is formed in a flat shape like the reflecting surface 19 in the first embodiment described above. As compared with the above, more light emitted from the light emitting element 11 can be guided to the light guide surface 20. For example, in the first embodiment, the light reflected by the reflective surface 19 on the surfaces on both sides in the X direction of the light guide plate 13 can be reflected by the curved surface portion 42b and guided to the light guide surface 20 in the present embodiment. . Thereby, the luminance on the light emitting surface 16 can be increased.

  Further, by configuring the reflecting surface 42 to include the concave curved surface portion 42b as in the present embodiment, the dimensions of the light introducing portions 17 and 41 can be compared to the case where the entire reflecting surface is formed in a flat shape. , The distance from the emitting surface 11a of the light emitting element 11 to the reflecting surface 42 can be increased. For example, as shown in FIG. 5, the distance W1 from the emission center of the emission surface 11a of the light emitting element 11 to the reflection surface 42 is made longer than the distance W0 when the entire reflection surface is formed in a flat shape. Can do.

  As a result, the light emitted from the light emitting element 11 can be incident on the reflecting surface 42 in a state where the light emitting element 11 is more widely spread. Therefore, when the same light emitting element 11 is used, the light emitting element is spread over a wider range of the reflecting surface 42. 11 can be incident. Therefore, since the light emitted from the light emitting element 11 can be greatly expanded in the X direction, the size of the dark area can be further reduced. As a result, the luminance unevenness between the light emitting element 11 and the portion between the light emitting elements 11 can be further suppressed, so that the luminance unevenness on the light emitting surface 16 can be further suppressed.

  As described above, in the present embodiment, the light emitted from the light emitting element 11 can be greatly expanded in the X direction parallel to the light guide surface 20, so that the directivity of the light emitted from the light emitting element 11 is high and the spread angle is large. This is particularly effective when it is small. When the light emitting element 11 having such a small divergence angle is used, by using the reflecting surface 42 including the curved surface portion 42b, the portion of the light emitting element 11 and the light emission are compared with the case where the entire reflecting surface is used. The luminance unevenness with the portion between the elements 11 can be more reliably suppressed, and the luminance unevenness on the light emitting surface 16 can be more reliably suppressed.

  In the present embodiment, since the curved surface portion 42b is formed in a concave curved surface shape, more of the light incident on the reflecting surface 42 is more uniform in the incident direction with respect to the light guide surface 20, specifically, the light guide. The light can be guided to the light guide surface 20 as light substantially perpendicular to the surface 20. In order to guide the light guided to the light guide surface 20 to the light emitting surface 16 with high efficiency, it is only necessary to provide the light guide plate 13 with a reflection structure corresponding to this direction. A reflection structure capable of guiding the guided light to the light emitting surface 16 of the light guide plate 13 with high efficiency can be easily configured by the light guide plate 13. By providing such a reflection structure, the light guided to the light guide surface 20 can be reflected toward the light emitting surface 16 with high efficiency. Therefore, in this embodiment, the brightness | luminance in the light emission surface 16 can be raised more easily.

  The curved surface portion 42b is formed as a continuous curved surface, and is formed so as to be defined by one radius of curvature in the present embodiment, but the shape of the curved surface portion 42b is not limited to this. For example, the curved surface portion 42b may have a shape in which a plurality of curved surfaces defined by different curvature radii are continuously connected.

  FIG. 6 is a plan view showing a configuration of an illumination device 50 according to the fourth embodiment of the present invention. In the illuminating device 50 of this Embodiment, since the structure of those other than the light introducing | transducing part 17 of the illuminating device 1 of 1st Embodiment is the same, the same referential mark is attached | subjected to the same structure and description. Is omitted.

  In the present embodiment, the incident surface 52 and the reflection surface 53 of each light introducing portion 51 have an angle θ between the light emission direction A and the light guide direction B from each light emitting element 11 exceeding 180 ° and 180 °. Each light emitting element 11 is formed so that the angle θ formed between the light emission direction A and the light guide direction B is 90 °. And less than 180 °, that is, an obtuse angle. In other words, each light emitting element 11 is provided so that the angle formed between the emission surface 11a and a virtual plane parallel to the light guide surface 20 is more than 90 ° and less than 180 °, and an obtuse angle. .

  In the present embodiment, the reflecting surface 53 is formed so that all of the light emitted from the light emitting element 11 is incident thereon. More specifically, the incident surface 52 of the light introducing portion 51 is connected to one end surface 13a in the X direction that is one end surface perpendicular to the Y direction of the light guide plate 13, and is inclined from the one end surface 13a in the X direction to one side in the X direction. It is a plane. The reflecting surface 53 is connected to the incident surface 52, and includes a planar first reflecting surface 53a that includes a line of intersection with the incident surface 52 and is inclined to one side in the Y direction from a virtual plane parallel to the X direction, and the first reflecting surface 53a. And a planar second reflecting surface 53b that includes a line of intersection with the first reflecting surface 53a and is inclined from the virtual plane parallel to the X direction to the other side in the Y direction.

  According to the present embodiment, the light emitted from the light emitting element 11 enters the reflection surface 53, more specifically, the first reflection surface 53 a or the second reflection surface 53 b and is guided to the light guide surface 20. Depending on the incident angle on the reflection surface 53, the light emitted from the light emitting element 11 is reflected by the reflection surface 53 a plurality of times and guided to the light guide surface 20.

  In this embodiment, as compared with the case where the angle formed between the light emission direction A and the light guide direction B is 90 ° or less as in the light introduction portion 17 in the first embodiment, the Y of the light introduction portion 51 is reduced. Since the dimension in the direction is slightly increased, the dimension L3 in the Y direction of the outer display portion 54 is slightly increased, but more light can be incident on the reflecting surface 53. As a result, more light directions can be defined by the reflecting surface 53, so that more light can be incident on the light guide surface 20 from a uniform direction. For example, the light can be incident as light substantially perpendicular to the light guide surface 20. Therefore, since the reflecting structure for guiding the light guided to the light guide surface 20 to the light emitting surface 16 can be provided more easily, the luminance on the light emitting surface 16 can be increased more easily.

  In the present embodiment, the reflecting surface 53 is formed so that all of the light emitted from the light emitting element 11 is incident thereon. Thereby, since all the light guided to the light guide surface 20 can be the light reflected by the reflection surface 53, the incident direction of the light with respect to the light guide surface 20 can be more reliably defined by the reflection surface 53. become. As a result, for example, light can be incident on the light guide surface 20 from a uniform direction, so that a reflection structure for guiding the light guided to the light guide surface 20 to the light emitting surface 16 is uniformly formed. Thus, more light guided to the light guide surface 20 can be guided to the light emitting surface 16. Therefore, since the reflecting structure can be configured more easily, the luminance on the light emitting surface 16 can be increased more easily.

  In a cross section perpendicular to the Z direction, an angle α3 formed by the incident surface 52 and the first reflecting surface 53a is selected to be 60 ° or more and 90 ° or less, and an angle γ1 formed by the first reflecting surface 53a and the second reflecting surface 53b. Is selected from 60 ° to 90 °. The angles α3 and γ1 are not limited thereto, but the angle α3 is preferably 60 ° or more and 90 ° or less, and the angle γ1 is preferably 60 ° or more and 90 ° or less. By setting the angle α1 to 60 ° or more and 90 ° or less and the angle γ1 to 60 ° or more and 90 ° or less, the light emitted from the light emitting element 11 can be incident on the reflecting surface 53 more reliably. As a result, the direction of the light guided to the light guide surface 20 can be more reliably defined by the reflective surface 53, so that a reflective structure for guiding the light to the light emitting surface 16 can be more easily provided. The brightness at the surface 16 can be increased more easily.

  In the present embodiment, the reflecting surface 53 is configured by two reflecting surfaces having different inclination directions with respect to a virtual plane parallel to the light guide surface 20, but may be configured by three or more reflecting surfaces.

  FIG. 7 is a plan view showing a configuration of a lighting device 60 according to the fifth embodiment of the present invention. In the illuminating device 60 of this Embodiment, since the structure other than the light introducing | transducing part 17 of the illuminating device 1 of 1st Embodiment is the same, the same referential mark is attached | subjected to the same structure and description. Is omitted.

  In the present embodiment, similar to the light introducing portion 6 in the fourth embodiment, the reflecting surface 62 of the light introducing portion 61 is provided so that all of the light emitted from the light emitting element 11 is incident thereon. In the present embodiment, the reflecting surface 62 is connected to one end portion of the incident surface 15, is connected to the first reflecting surface 62 a formed in a curved surface shape, and is connected to the other end portion of the incident surface 15, and is formed in a flat shape. 2 reflective surface 62b. More specifically, the first reflecting surface 62a has a concave curved surface shape, and protrudes from the incident surface 15 to one side in the Y direction and is curved to the other side in the Y direction. The second reflecting surface 62b is provided to face the first reflecting surface 62a.

  More specifically, the first reflecting surface 62 a is a curved surface that is continuous with the end portion on one side in the Y direction of the incident surface 15 and curves from the incident surface 15. More specifically, the first reflecting surface 62a has a circular cross section in a virtual plane perpendicular to the Z direction, and is formed in a uniform shape in the Z direction.

  More specifically, the second reflecting surface 62b is a plane that is continuous with the end of the incident surface 15 on the other side in the Y direction and is parallel to the X direction. The second reflecting surface 62b faces the first reflecting surface 62a, reflects the light emitted from the light emitting element 11 and guides it to the first reflecting surface 62a, and passes through the first reflecting surface 62a to the light guide surface 20. Lead. As described above, the second reflection surface 62 b guides the light emitted from the light emitting element 11 to the light guide surface 20 in cooperation with the first reflection surface 62 a.

  In the present embodiment, the light guide plate 13 is notched so that the surface portion on one side in the X direction is recessed on the other side in the X direction, and the reflective layer 14 is formed on the inner wall of the notched recess 63. Yes. Of the inner wall of the recess 63 in which the reflective layer 14 is formed, the portion facing the first reflective surface 62a becomes the second reflective surface 62b.

  In the present embodiment, the light emitted from the light emitting element 11 enters the first reflecting surface 62a and the second reflecting surface 62b. The light incident on the first reflecting surface 62a is reflected by the first reflecting surface 62a and guided to the light guide surface 20, or enters the second reflecting surface 62b. The light incident on the second reflecting surface 62b is reflected by the second reflecting surface 62b and guided to the first reflecting surface 62a, reflected by the first reflecting surface 62a, and guided to the light guide surface 20.

  As described above, the light reflected by the reflecting surface 62, more specifically, the curved first reflecting surface 62a of the reflecting surface 62, is guided to the light guide surface 20, so that the incident direction of the light with respect to the light guide surface 20 is reflected. The surface 62, more specifically, the first reflecting surface 62 a of the reflecting surface 62 can be defined. As a result, for example, light can be incident on the light guide surface 20 from a substantially uniform direction, so that a reflection structure for guiding the light guided to the light guide surface 20 to the light emitting surface 16 is uniformly formed. It becomes possible to do. Therefore, since such a reflection structure can be easily provided, the luminance at the light emitting surface 16 can be easily increased.

  FIG. 8 is a plan view showing a configuration of a lighting apparatus 70 according to the sixth embodiment of the present invention. In the illuminating device 70 of the present embodiment, the configuration other than the light introduction unit 17 of the illuminating device 1 of the first embodiment is the same, and thus the same configuration is denoted by the same reference numeral and described. Is omitted.

  The light introduction part 71 of the present embodiment includes a first light introduction part 72 similar to the light introduction part 17 in the first embodiment, and the first light introduction part 72 with respect to the central part in the X direction of the light guide plate 13. And the inverted second light introducing portion 73. Therefore, the light introducing portion 71 has a configuration in which the light introducing portion 17 in the first embodiment is arranged symmetrically with respect to the central portion in the X direction of the light guide plate 13. Therefore, the light emitting element 11 of the first light introducing portion 72 and the light emitting element 11 of the second light introducing portion 73 are set in the direction in which the light emitting surfaces face each other. Two first and second light introducing portions 72 and 73 are provided.

  In the present embodiment, an even number of light emitting elements 11 are provided, and an even number of light introducing portions 71 are provided correspondingly. The even number of light emitting elements 11 and light introducing portions 71 are arranged symmetrically with respect to the central portion in the X direction of the light guide plate 13.

  In the present embodiment, in the first light introducing portion 72, the incident surface 15 is formed at one end in the X direction parallel to the light guide surface 20, and the reflecting surface 19 is formed from one end to the other end in the X direction. Has been. In the second light introducing portion 73, the incident surface 15 is formed at the other end portion in the X direction parallel to the light guide surface 20, and the reflecting surface 19 is formed from the other end portion in the X direction to one end portion. That is, the light introduction part 71 of the present embodiment includes two sets of two light introduction parts 71 in which the reflection surface 19 is formed on the same side in the X direction.

  As described above, by providing at least two light introducing portions 71 formed on the same side in the X direction that is parallel to the light guide surface 20, the reflecting surface 19 is reflected by the reflecting surface 19 of the light introducing portion 71. The direction of light can be made uniform. Therefore, since the reflection structure capable of guiding light to the light emitting surface 16 with high efficiency can be easily provided on the back surface 24 of the light guide plate 13, the luminance on the light emitting surface 16 can be more easily increased.

  FIG. 9 is a plan view showing a configuration of an illuminating device 75 according to a seventh embodiment of the present invention, and FIG. 10 is an enlarged view showing the coupling portion 77 shown in FIG. In the illuminating device 75 of this Embodiment, since the structure of those other than the light introduction part 17 of the illuminating device 1 of 1st Embodiment is the same, the same referential mark is attached | subjected to the same structure and description. Is omitted.

  The light introducing portion 76 of this embodiment includes a coupling portion 77 between the emission surface 11 a and the incident surface 15 of the light emitting element 11. The coupling portion 77 is equal to the refractive index of at least one of the exit surface portion 11b where the exit surface 11a of the light emitting element 11 is formed and the entrance surface portion 15a where the entrance surface 15 of the light introducing portion 76 is formed, or The refractive index is between the refractive index of the exit surface portion 11 b of the light emitting element 11 and the refractive index of the incident surface portion 15 a of the light introducing portion 76.

  In the present embodiment, since the incident surface portion 15a of the light introducing portion 76 is a part of the light guide plate 13, the coupling portion 77 has a refractive index of at least one of the output surface portion 11b of the light emitting element 11 and the light guide plate 13. It is equal or has a refractive index between the refractive index of the output surface portion 11 b of the light emitting element 11 and the refractive index of the light guide plate 13. In the present embodiment, the incident surface portion 15 a of the light introducing portion 76 is realized by a recess formed on one end surface of the light guide plate 13 in the X direction. The coupling portion 77 is provided so that a part thereof is buried in the recess of the light guide plate 13.

  In this Embodiment, the light-guide plate 13 is comprised with the acrylic resin or the polycarbonate resin, and the refractive index is about 1.49-1.59. The light emitting element 11 is realized by an LED, the light emitting surface of the LED is often covered with a silicone resin, and the light emitting surface portion 11b of the LED is often formed of a silicone resin. Since the refractive index of the silicone resin is about 1.4 to 1.52, when the emission surface portion 11 b of the light emitting element 11 is formed of silicone resin, the refractive index of the emission surface portion 11 b of the light emitting element 11 is the same as that of the light guide plate 13. It becomes almost equal to the refractive index. Therefore, it is preferable that the coupling portion 17 is formed of a silicone-based resin having a refractive index comparable to that of the emission surface portion 11b of the light emitting element 11 and the light guide plate 13.

  By providing the coupling portion 77 between the emission surface 11a of the light emitting element 11 and the incident surface 15 of the light introducing portion 76 as in the present embodiment, the emitting surface 11a of the light emitting element 11 and the incident surface of the light introducing portion 76 are provided. Since the reflectance of light at the interface with the light source 15 can be reduced, the coupling efficiency between the light emitting element 11 and the light introducing portion 76 can be increased. Therefore, a large amount of light can be made incident from the light emitting element 11 to the light introducing portion 76, so that the luminance on the light emitting surface 16 can be further increased.

  FIG. 11 is a plan view showing a configuration of an illumination device 80 according to the eighth embodiment of the present invention. In the illuminating device 80 of this Embodiment, since the structure of those other than the light introduction part 17 of the illuminating device 1 of 1st Embodiment is the same, the same referential mark is attached | subjected to the same structure and description. Is omitted.

  In the light introducing portion 81 of the present embodiment, the reflecting surface 82 has a light emitting portion 82 a that emits light by light emitted from the light emitting element 11. In the present embodiment, the entire reflecting surface 82 is the light emitting portion 82a. The light emitting portion 82 a is formed by forming a light emitting layer 83 between the light guide plate 13 and the reflective layer 14.

  The light emitting layer 83 is formed of a light emitting material such as a fluorescent material that emits fluorescence by light emitted from the light emitting element 11. In the present invention, the “fluorescent material” includes a material that emits phosphorescence by photoexcitation. The light emitting layer 83 is formed by applying a light emitting material such as the above-described fluorescent material to the reflective layer 14 or the portion where the reflective surface 82 of the light guide plate 13 is formed.

  The light emitting material constituting the light emitting layer 83 is selected according to the wavelength of light emitted from the light emitting element 11. For example, when an LED that emits blue light or ultraviolet light is used as the light emitting element 11, a light emitting portion that emits blue or longer wavelength light by using a fluorescent material excited by light emitted from the LED. 82a can be realized. If a yellow light emitting fluorescent material that emits yellow light is used as the fluorescent material constituting the light emitting layer 83, white light emission can be realized by mixing with blue, and furthermore, the fluorescent material can be applied to each reflective layer 14 or the light guide plate 13. By making the amount constant, it is possible to suppress variation in chromaticity for each LED. In other words, unlike the case of using a white light emitting LED, light can be emitted without being affected by variations in chromaticity for each LED, and white light emission with little variation in chromaticity can be realized.

  Thus, in the present embodiment, since the reflecting surface 82 has the light emitting portion 82a, the light emitting portion 82a is caused to emit light by the light emitted from the light emitting element 11, and the light emitted from the light emitting portion 82a is guided to the light guide surface 20. Can lead to. Therefore, for example, when the chromaticity variation occurs in the light emitted from the light emitting element 11, by appropriately selecting the emission color from the light emitting portion 82a, the influence of the chromaticity variation is suppressed, and the color on the light emitting surface 16 is reduced. Variation in the degree can be suppressed.

  FIG. 12 is a plan view showing a configuration of a lighting device 85 according to the ninth embodiment of the present invention. In the illuminating device 85 of this Embodiment, since the structure of those other than the light guide 12 of the illuminating device 1 of 1st Embodiment is the same, the same referential mark is attached | subjected to the same structure and description. Is omitted.

  In the present embodiment, the light guide 86 includes the side-side reflecting surface 87 which is another reflecting surface that reflects the light emitted from the light emitting element 11 or the light reflected by the reflecting surface 19 and guides it to the light guiding surface 20. Have. The side reflecting surfaces 87 are formed on both sides of the light guide plate 13 in the X direction. Similar to the reflective surface 19, the side-surface reflective surface 87 is formed by providing reflective layers 88 on the surface portions on both sides in the X direction of the light guide plate 13, and more specifically, an interface between the light guide plate 13 and the reflective layer 88. It is. The reflective layer 88 that defines the side-side reflective surface 87 is formed in the same manner as the reflective layer 14 of the light introducing portion 17.

  In the present embodiment, the reflection layer 88 is formed on the entire surface portion on both sides in the X direction of the light guide plate 13, whereby the side surface reflection surface 87 is formed over the entire Y direction, which is the longitudinal direction of the light guide 86.

  As described above, in the present embodiment, the light guide 86 has the side-surface-side reflecting surface 87, so that the light emitted from the light-emitting element 11 does not enter the reflecting surface 19 of the light introducing portion 17 and is reflected on the side-surface side. The light incident on the surface 87 and the light reflected by the reflecting surface 19 of the light introducing portion 17 and incident on the side reflecting surface 87 can be guided to the light guide surface 20. Therefore, in the present embodiment, at least a part of the light emitted from the light emitting element 11 is reflected by the reflection surface 19 of the light introducing portion 17 and guided to the light guide surface 20, and at least the remaining light is A part of the light can be reflected by the side reflecting surface 87 and guided to the light guide surface 20. As a result, the reflection efficiency on the surfaces on both sides in the X direction of the light guide 13 can be improved, and more light emitted from the light emitting element 11 can be guided to the light guide surface 20 and guided to the surface light emitting unit 18. The brightness on the light emitting surface 16 can be further increased.

  In the above embodiment, the reflection surface of the light introducing portion is composed of at least one of a flat surface portion and a curved surface portion. As a result, it is possible to easily realize a suitable reflecting surface in accordance with the characteristics of light emitted from the light emitting element 11, such as directivity.

  Moreover, in this Embodiment, although the reflective surface of the light introduction part is formed smoothly, you may form in uneven | corrugated shape. Thus, by forming the reflection surface in a concavo-convex shape, the light emitted from the light emitting element 11 and incident on the reflection surface can be diffused by the concavo-convex portion formed on the reflection surface. Therefore, the luminance unevenness between the light emitting element 11 portion in the X direction parallel to the light guide surface 20 and the portion between the light emitting elements 11 can be further suppressed, and the luminance unevenness on the light emitting surface 16 can be further suppressed. The uneven reflecting surface is formed, for example, by forming a three-dimensional structure such as a prism shape on the surface portion where the reflecting surface of the light guide plate 13 is formed.

  FIG. 13 is a plan view showing an example of an uneven reflecting surface 90. In the example shown in FIG. 13, a plurality of V-shaped groove portions 91 are formed on the surface portion of the light guide plate 13 where the reflection surface 90 is formed, and a prism structure is formed on the reflection surface 90 by the groove portions 91. The reflective layer 14 is formed in a portion of the surface portion where the reflective surface 90 of the light guide plate 13 is formed, excluding a portion where the groove portion 91 is formed, and a space between the groove portion 91 and the reflective layer 14 is formed. Functions as a prism. The groove of the groove portion 91 may be filled with a filler. In the example shown in FIG. 13, the plurality of groove portions 91 are formed so that the depth gradually increases as the distance from the incident surface 15 increases. The prism structure formed on the reflecting surface is not limited to the structure shown in FIG.

It is a top view which shows the structure of the illuminating device 1 which is the 1st Embodiment of this invention. It is sectional drawing which shows the cross-sectional structure of the illuminating device 1 in cut surface line S2-S2 shown in FIG. It is a figure which contrasts and shows the light emission state in the illuminating device 1 of this embodiment, and the light emission state in the illuminating device 100 of a prior art. It is a top view which shows the structure of the illuminating device 30 which is the 2nd Embodiment of this invention. It is a top view which shows the structure of the illuminating device 40 which is the 3rd Embodiment of this invention. It is a top view which shows the structure of the illuminating device 50 which is the 4th Embodiment of this invention. It is a top view which shows the structure of the illuminating device 60 which is the 5th Embodiment of this invention. It is a top view which shows the structure of the illuminating device 70 which is the 6th Embodiment of this invention. It is a top view which shows the structure of the illuminating device 75 which is the 7th Embodiment of this invention. It is an enlarged view which expands and shows the coupling | bond part 77 shown in FIG. It is a top view which shows the structure of the illuminating device 80 which is the 8th Embodiment of this invention. It is a top view which shows the structure of the illuminating device 85 which is the 9th Embodiment of this invention. 6 is a plan view showing an example of an uneven reflecting surface 90. FIG. It is a top view which shows the structure of the illuminating device 100 of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Illuminating device 2 Liquid crystal display device 3 Liquid crystal display panel 11 Light emitting element 12 Light guide 13 Light guide plate 14 Reflective layer 15 Incident surface 16 Light emitting surface 17 Light introduction part 18 Surface light emission part 19 Reflecting surface 20 Light guide surface

Claims (8)

A point light source that emits light in a radial manner, an incident surface that is translucent and receives light emitted from the point light source, and an exit surface that is formed substantially perpendicular to the incident surface and from which light incident from the incident surface is emitted A lighting device comprising:
The light guide is
A plurality of light introducing portions having the incident surface and a reflective surface that is formed so that at least part of light incident from the incident surface is incident and reflects the incident light to a virtual plane that is perpendicular to the emission surface Including
The point light source includes the same number of point light sources as the light introduction part,
Each point light source is provided to face the incident surface of the light introducing portion so that the light emission direction is inclined with respect to the light guide direction perpendicular to the virtual plane.
The plurality of light introducing portions are provided side by side in a direction parallel to the virtual plane.
Among the plurality of light introducing portions, at least two light introducing portions have an incident surface formed at one end portion in a direction parallel to the virtual one plane and extend from one end portion to the other end portion in a direction parallel to the virtual one plane. A lighting device, wherein a reflecting surface is formed.   The lighting device according to claim 1, wherein each point light source is provided such that a light emission direction is perpendicular to a light guide direction.   2. The illumination device according to claim 1, wherein each point light source is provided so that an angle formed between a light emitting direction and a light guiding direction is more than 90 ° and less than 180 °.   The lighting device according to claim 1, wherein the reflecting surface is formed in an uneven shape.   The illumination device according to any one of claims 1 to 4, wherein the reflecting surface includes at least one of a flat surface portion formed in a flat shape and a curved surface portion formed in a curved surface shape. .   The lighting device according to claim 1, wherein the reflecting surface has a light emitting portion that emits light by light emitted from a point light source. The light introduction part
Refraction of at least one of the exit surface portion where the exit surface is formed and the entrance surface portion where the entrance surface is formed between the exit surface from which the light from the point light source is emitted and the entrance surface of the light introducing portion The illumination device according to claim 1, further comprising: a coupling portion having a refractive index equal to a refractive index or having a refractive index between the refractive index of the exit surface portion and the refractive index of the entrance surface portion. .   The light guide has another reflection surface that reflects light emitted from a point light source or light reflected by the reflection surface and guides the light to the virtual plane. Lighting device described in one.

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