JP2012190554A - Illumination apparatus, and display device equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination apparatus capable of enhancing light extraction efficiency and improving front-face brightness, and to provide a display device equipped with the same.SOLUTION: The illumination apparatus is provided with a light guide plate 32 having an emission surface 32a, a rear surface 32b facing the emission surface and with a reflection film 38 formed, and an incident surface 32c crossing the emission surface, and a light source 34 making light incident from the incident surface to the light guide plate. The rear surface 32b of the light guide plate includes a plurality of first slant-surfaces 42a slanting relative to the emission surface and with the longer distance to the emission surface the farther away from the light source, and a plurality of second slant-surfaces 42b slanting relative to the emission surface and arranged continuously with the first slant-surfaces at a side away from the light source. An angle formed between the second slant-surface and the emission surface is larger than that formed between the first slant surface and the emission surface.

Description

  Embodiments described herein relate generally to a lighting device used for a display device and a display device including the same.

  2. Description of the Related Art In recent years, as a liquid crystal display device, for example, a TFT type liquid crystal panel has become widespread as a display for portable devices such as notebook PCs and PDAs in addition to large-sized home televisions. Such a liquid crystal display device conventionally employs a backlight system in which a light source is disposed on the back side of the liquid crystal panel and the liquid crystal panel is illuminated with light from the light source. As a backlight unit adopted in the backlight system, a flat light guide plate made of acrylic resin or the like that is excellent in transmitting light from a light source lamp such as a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED) There are an edge light system that irradiates the front side with multiple reflections, and a direct type system that does not use a light guide plate.

The edge light type backlight unit includes a light guide plate arranged in parallel to the liquid crystal panel on the back side of the liquid crystal panel, and a light source provided to face the side edge of the light guide plate. The light emitted from the light source is incident on the light guide plate, then propagates in the horizontal direction in the light guide plate by total reflection, and is emitted obliquely upward by a groove formed on the lower surface of the light guide plate. The emitted light is efficiently irradiated to the liquid crystal panel by changing the direction in the vertical direction with an optical sheet such as a prism sheet provided in front of the light guide plate. In order to efficiently use light from the light source as illumination light, a reflector is disposed on the back surface of the light guide plate.
On the other hand, for a direct backlight unit, a light recycling method has been proposed in which a non-absorptive color filter is disposed on the exit surface side and unnecessary light is reused in each sub-pixel.

US Patent Publication No. 2009-0190072

Journal of Optics A, 7 (2005), P111-117

  There is a strong demand for liquid crystal display devices that are lightweight, have low power consumption, and are thin. Accordingly, the backlight unit mounted on the liquid crystal display device is also required to be lightweight and have low power consumption. However, in the above-described edge light type backlight unit, the light utilization efficiency (the ratio of the amount of light passing through the effective display area of the liquid crystal panel to the total amount of light emitted from the light source) is only about 5 to 7%, which is low. It is hard to say that they are meeting the demand for power consumption. In an edge-light type backlight unit, the amount of light extracted from the display surface (extracted light amount) increases only by disposing a non-absorbing color filter on the output surface side of the light guide plate, but the directivity distribution of the output angle is widened. As a result, the most required increase in front luminance is only about 10 to 20%.

  This invention is made | formed in view of such a situation, The subject is providing the illuminating device which can improve light extraction efficiency and front luminance, and a display apparatus provided with the same.

  According to the embodiment, the illumination device includes a light guide plate having an exit surface, a back surface facing the exit surface and having a reflective film formed thereon, and an entrance surface intersecting the exit surface; A light source that makes light incident on the light guide plate, and a back surface of the light guide plate is inclined with respect to the light exit surface and has a plurality of first inclined surfaces that are longer with the light exit surface as the distance from the light source increases. A plurality of second inclined surfaces that are inclined with respect to the emission surface and are continuous with the far side of the first inclined surface from the light source, and an angle formed by the second inclined surface with the emission surface is the first inclination It is characterized in that the surface is larger than the angle formed with the exit surface.

FIG. 1 is a cross-sectional view of a liquid crystal display device according to a first embodiment. FIG. 2 is a plan view showing a light guide plate of a backlight unit of the liquid crystal display device. FIG. 3 is an enlarged sectional view showing a liquid crystal display panel of the liquid crystal display device. FIG. 4 is an enlarged cross-sectional view of the light guide plate. FIG. 5 is a diagram illustrating a directivity angle (calculated value) of outgoing light according to an inclination angle of an inclined surface of the light guide plate. FIG. 6 is a diagram illustrating a directivity angle (calculated value) of emitted light according to different inclination angles of the inclined surface of the light guide plate. FIG. 7 is a cross-sectional view of the liquid crystal display device according to the second embodiment. FIG. 8 is an enlarged cross-sectional view of a light guide plate in the liquid crystal display device.

Hereinafter, a liquid crystal display device according to an embodiment will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 shows the liquid crystal display device according to the first embodiment as a display device, and FIG. 2 shows a backlight unit that functions as a lighting device.
As shown in FIG. 1, the liquid crystal display device 10 includes a rectangular liquid crystal display panel 12 and a substantially rectangular backlight unit 14 arranged on the back side (back side) of the liquid crystal display panel 12. The liquid crystal display panel 12 and the backlight unit 14 are mounted on a substantially rectangular resin or metal support frame 30. A rectangular frame-shaped metal bezel 33 is placed on the peripheral edge of the liquid crystal display panel 12, and the bezel is joined to the support frame 30. Thereby, the liquid crystal display panel 12 and the backlight unit 14 are held in a state of being sandwiched between the support frame 30 and the bezel 33.

  FIG. 3 shows a cross section of the liquid crystal display panel 12. As shown in FIGS. 1 and 3, the liquid crystal display panel 12 includes a rectangular array substrate 16 and a counter substrate 18 that are arranged to face each other with a gap therebetween, a liquid crystal layer 20 that is sealed between these substrates, and the like. . The array substrate 16 includes, for example, a transparent rectangular glass substrate, an interference color filter (CF) layer 22 formed on the upper surface (inner surface) of the glass substrate, and a buffer layer 24 formed on the interference CF layer. And a TFT array layer 26 formed thereon. The buffer layer 24 is for flattening the unevenness of the interference CF layer 22. A large number of display pixels, switching elements (TFTs), and wirings (not shown) are formed in the effective display area of the TFT array layer 26, and a drive circuit is formed outside the effective display area.

  The counter substrate 18 is made of, for example, a transparent rectangular glass substrate, and the peripheral edge thereof is affixed to the peripheral edge of the array substrate 16 with a sealing material 28. The liquid crystal layer 20 is sandwiched between the TFT array layer 26 and the counter substrate 18.

  The interference CF layer 22 that functions as a color selection layer has a structure in which wavelength selective transmission filters having three transmission regions that are three sub-pixel regions of R, G, and B are arranged in a predetermined pattern, and are non-absorbing. Configure the filter. The three transmission regions of the interference CF layer 22 correspond to the R, G, and B subpixels of the TFT array layer 26, respectively. Each sub-pixel region of the interference CF layer 22 transmits light having a wavelength in a specific wavelength region with high transmittance, and light having other wavelengths is reflected toward the backlight unit 14 with high reflectance. Has characteristics. The reflected light is reused (light recycling). For example, the R sub-pixel region of the interference CF layer 22 selectively transmits only light having a wavelength longer than 620 nm (red light) and reflects light having other wavelengths to the backlight unit 14 side.

  As such a wavelength selective transmission filter, for example, a dielectric multilayer film, a one-dimensional, two-dimensional, or three-dimensional photonic crystal can be used in addition to an interference color filter formed of a laminated film of organic thin films. In the present embodiment, the interference CF layer 22 that is a wavelength selective transmission filter is built in the liquid crystal display panel 12. However, the present invention is not limited to this, and the wavelength selective transmission filter is provided on the backlight unit 14 side. Also good.

  As shown in FIGS. 1, 2, and 4, the backlight unit 14 is configured as an edge light type planar illumination device, and includes, for example, an acrylic rectangular light guide plate 32 and a plurality of LEDs 34 as a light source. And a reflective film 38 formed on the back surface of the light guide plate 32.

  The light guide plate 32 is formed in a rectangular shape having a size corresponding to the liquid crystal display panel 12. The light guide plate 32 has an upper surface on which a flat emission surface 32a is formed, a back surface 32b opposite to the upper surface, and four side surfaces extending orthogonally to the emission surface 32a, and one side surface forms an incident surface 32c. . A reflective film 38 is formed on the entire back surface 32 b of the light guide plate 32. The liquid crystal display panel 12 described above is disposed so as to overlap the light guide plate 32, and faces the emission surface 32 a of the light guide plate 32.

  For example, the four LEDs 34 are attached to the incident surface 34 c of the light guide plate 32 and are arranged at predetermined intervals along the width direction Y of the light guide plate 32. In consideration of the reduction in thickness of the light guide plate 32, the LED 34 is a surface-mounted type side surface light emission and has a small thickness.

  The back surface 32b of the light guide plate 32 is formed on a plurality of recesses processed to emit light that has propagated laterally in the light guide plate 32 by total reflection in the vertical direction, and on the entire processed surface of these recesses. The metal reflective film 38 is provided. Each recess is formed by a V-groove 40 including a first inclined surface 42a and a second inclined surface 42b having different inclination angles. Each of the plurality of V grooves 40 extends from one side of the light guide plate to the other side along the Y direction, here, the width direction of the light guide plate 32, i.e., the direction parallel to the incident surface 32c. Along the longitudinal direction X of the light guide plate 32, the light guide plate 32 is formed side by side from one end to the other end in the length direction.

  The V-groove 40 includes a first inclined surface 42a on which light propagating in the lateral direction in the light guide plate 32 (hereinafter referred to as propagating light) is reflected multiple times, and a first inclined surface 42 for emitting the light in the light guide plate 32 in the vertical direction. The two inclined surfaces 42b are formed in a wedge shape. The inclination angle α1 of the first inclined surface 42a is set to 2 to 20 degrees, for example, 2 degrees with respect to the reference plane A parallel to the upper surface 32a of the light guide plate 32, and the inclination angle α2 of the second inclined surface 42b is For example, it is formed at 40 to 45 degrees. The depth of the V groove 40 is, for example, 4 to 5 μm.

  The plurality of first inclined surfaces 42a are inclined with respect to the emission surface 32a such that the distance from the emission surface 32a increases as the distance from the LED 34 increases. The plurality of second inclined surfaces 42b are inclined with respect to the emission surface 32a and are continuous to the side farther from the LED 34 of the first inclined surface 42a.

  The pitch P or width of the V groove 40 along the longitudinal direction X is adjusted according to the distance from the light source so that the illuminance distribution of the emitted light is uniform in the plane of the light guide plate 32. For example, the pitch P of the V grooves 40 is formed so as to gradually increase as the distance from the LED 3 increases. In other words, the pitch P of the V-groove 40 along the longitudinal direction X of the light guide plate 32 is modulated according to the distance from the light source so that the brightness in the display surface is uniform, and is within a range of 50 μm to 150 μm. Thus, it gradually increases as the distance from the light source increases.

  The back surface 32b of the light guide plate 32 on which the metal reflecting film 38 is formed is a repetition of the first inclined surface 42a and the second inclined surface 42b, but the inclination angle α1 of the first inclined surface 42a is the same as that of the second inclined surface 42b. It is extremely small compared to the inclination angle α2. Therefore, the total area of the second inclined surface 42b is sufficiently smaller than the total area of the first inclined surface 42a.

  The light guide plate 32 only needs to be transparent. Specifically, in addition to a transparent substrate such as glass or acrylic resin, heat resistance capable of depositing a metal thin film such as polycarbonate (PC), (PES), polyethylene naphthalate (PEN), etc. A transparent film can be used.

  The light guide plate 32 configured as described above is disposed such that the first inclined surface 42 a of each V-groove 40 is parallel to the interference CF layer 22. That is, the light guide plate 32 is disposed with its upper surface 32a inclined at an angle α1, for example, 2 degrees with respect to the interference CF layer 22 and the array substrate 16 of the liquid crystal display panel 12, and on the light source side of the light guide plate 32. It is inclined so that the end portion is lowered.

  As shown in FIGS. 1, 2, and 4, the inclination angle α <b> 1 of the light guide plate 32 is defined by the thickness of the spacer 44 inserted between the liquid crystal display panel 12 and the incident side end of the light guide plate 32. The In order to prevent light absorption by the spacer 44, a reflective layer 46 is formed on the light guide plate 32 in a region where the spacer 44 is disposed. Each reflective layer 46 is formed of a reflective metal thin film or a reflective sheet. Considering the effective use of light, it is better to reduce the light incident on the reflective area 46 as much as possible.

  The spacers 44 are rectangular points that are both 2 mm or less in length and width, and are disposed at two corners at least on both sides of the side where the LEDs 34 are disposed. Depending on the dimensions of the liquid crystal display panel 12, the dimensions and locations of the spacers 44 and the reflective layer 46 may be increased. In the present embodiment, a plurality of, for example, three spacers 44 are arranged at intervals along the width direction Y of the light guide plate 32.

  Further, in order to maintain the inclined state of the light guide plate 32, another spacer 48 is provided between the end of the light guide 32 opposite to the light source and the support frame 30. Further, the liquid crystal display panel 12 and the backlight unit 14 are fixed by a support frame and a bezel 33 in order to eliminate positional displacement in the in-plane direction between the liquid crystal display panel 12 and the backlight unit 14.

  In the backlight unit 14 configured as described above, a path of light until light emitted from the LED 34 is emitted from the display surface of the liquid crystal display panel 12 will be described. As shown in FIG. 4, the omnidirectional light emitted from the LED 34 enters the light guide plate 32 and propagates through the light guide plate by multiple reflection. The first inclined surface 42a of the light guide plate 32 has an effect of collimating the propagation light. Specifically, the propagating light incident on the first inclined surface 42a is reflected here, but is collimated by twice the inclination angle α1 of the first inclined surface 42a, that is, 4 degrees for each reflection, and the light guide plate 32 approaches the direction parallel to the upper surface 32a of 32. Accordingly, the propagation light approaches the parallel light as the propagation distance becomes long and becomes substantially parallel light. Then, the substantially parallel light incident on the second inclined surface 42b is reflected on the upper surface 32a side and is emitted from the upper surface 32a of the light guide plate 32 at an emission angle of 20 degrees or less.

  The collimating action of the light guide plate 32 as described above has a great influence on the directivity angle of outgoing light (compared to when no light is recycled). For example, as shown in FIG. 5 and FIG. 6, when a light source having the same directivity angle is set on the incident surface 32c of the light guide plate 32 and the inclination angle α1 of the first inclined surface 42a is 3.25 degrees, In some cases, the directivity angles of the emitted light were compared (calculated values). From these figures, it can be seen that the inclination angle of 0 degree spreads by about 20 degrees in the directivity angle distribution.

  The light emitted from the light guide plate 32 passes through the array substrate 16 of the liquid crystal display panel 12 and enters the interference CF layer 22. As described above, the interference CF layer 22 is composed of three R, G, and B sub-pixel regions. Each sub-pixel region transmits light in a specific wavelength region, and transmits light in other wavelength regions. It is reflected on the light plate 32 side and reused (light recycling). For example, the R sub-pixel region selectively transmits only light having a wavelength longer than 620 nm (red light) and reflects light having other wavelengths to the light guide plate 32 side. The light reflected by the interference CF layer 22 enters the light guide plate 32, is reflected by the first inclined surface 42a, and is returned to the interference CF layer 22 again. In this way, the light emitted from the light guide plate 32 is subjected to multiple reflections between the first inclined surface 42a and the interference CF layer 22 until the wavelength coincides with the transmission wavelength region of the sub-pixel region of the interference CF layer 22. It spreads in the direction. At this time, since light is multiply reflected between two parallel planes, that is, the first inclined surface 42a and the interference CF layer 22, the emission angle of the light emitted from the liquid crystal display panel 12 is increased. Absent. Thereby, the spread of each directional distribution at the time of light recycling is suppressed.

  As described above, of the light emitted from the light guide plate 32 in the vertical direction, the light that does not pass through the sub-pixel region of the interference CF layer 22 is formed by forming the non-absorption type interference CF layer 22 and the metal reflection film 38. The light is emitted toward the liquid crystal display panel 12 from the sub-pixel region having the matched transmission wavelength region through multiple reflections with the one inclined surface 42a (light recycling). At this time, since the ratio of the area occupied by the groove-shaped second inclined surface 42b to the area of the light guide plate 32 is only about 5%, the number of times the recycled light is transmitted in the thickness direction of the light guide plate 32 during light recycling. Even if the light passes, the recycled light is hardly reflected by the second inclined surface 42b.

  According to the backlight unit 14 configured as described above and the liquid crystal display device 10 including the backlight unit 14, it is possible to separate the paths of the multiple reflections from the recycled light and the propagated light. It is possible to simultaneously suppress the spread of the directivity angle distribution and the vertical emission from the light guide plate. As a result, a backlight unit capable of improving light extraction efficiency and front luminance and a display device including the backlight unit can be obtained.

  Next, a liquid crystal display device according to another embodiment will be described. In other embodiments described below, the same parts as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof will be omitted.

(Second Embodiment)
7 and 8 show a liquid crystal display device 10 according to the second embodiment. The liquid crystal display device 10 has the same basic configuration as the liquid crystal display device according to the first embodiment, and the shape of the light guide plate 32 of the backlight unit 14 is different.
As shown in FIGS. 7 and 8, the light guide plate 32 is formed in a rectangular shape having a size corresponding to the liquid crystal display panel 12 and in a wedge shape. The light guide plate 32 has an upper surface on which a flat emission surface 32a is formed, a back surface 32b opposite to the upper surface, and four side surfaces extending orthogonally to the emission surface 32a, and one side surface forms an incident surface 32c. . A reflective film 38 is formed on the entire back surface 32 b of the light guide plate 32. The liquid crystal display panel 12 is disposed so as to overlap the light guide plate 32, and faces the emission surface 32 a of the light guide plate 32.

  For example, the four LEDs 34 are attached to the incident surface 32 c of the light guide plate 32, and are arranged at predetermined intervals along the width direction Y of the light guide plate 32. In consideration of the reduction in thickness of the light guide plate 32, the LED 34 is a surface-mounted type side surface light emission and has a small thickness.

  The back surface 32b of the light guide plate 32 is inclined by an angle α1 with respect to the upper surface 32a. Thereby, the light guide plate 32 is formed in a wedge shape in which the end on the incident surface 42c side is thin and becomes thicker toward the opposite end. The rear surface 32b constitutes a first inclined surface 42a that is inclined by an inclination angle α1 with respect to a reference surface A parallel to the upper surface 32a of the light guide plate 32. The inclination angle α1 is set to 2 to 20 degrees, for example, 2 degrees.

  A plurality of V-grooves 40 are formed as recesses on the back surface 32 b of the light guide plate 32. Each of the plurality of V grooves 40 extends from one side of the light guide plate to the other side along the Y direction, here, the width direction of the light guide plate 32, i.e., the direction parallel to the incident surface 32c. The light guide plate 32 is formed side by side in the longitudinal direction X with a predetermined interval. Of the two inclined surfaces constituting the V-groove 40, the inclined surface on the LED light source 34 side constitutes a second inclined surface 42b, and the second inclined surface 43b is inclined by an inclination angle α2 with respect to the reference surface A. Inclined. The inclination angle α2 is set to 40 to 45 degrees, for example, 43 degrees. The inclination angle of the other inclined surface defining the V groove 40 may be any angle as long as the V groove 40 can be formed at a desired pitch. The depth of the V groove 40 is, for example, 4 to 5 μm.

  The pitch of the V-grooves 40 along the longitudinal direction X of the light guide plate 32 is modulated according to the distance from the LED 34 so that the brightness in the display surface is uniform, and within a range of 50 μm to 150 μm from the light source. It gradually increases as you leave.

  As described above, on the back surface 32b of the light guide plate 32, the plurality of first inclined surfaces 42a are inclined with respect to the emission surface 32a such that the distance from the emission surface 32a increases as the distance from the LED 34 increases. The plurality of second inclined surfaces 42b are inclined with respect to the emission surface 32a and are continuous to the side farther from the LED 34 of the first inclined surface 42a.

  The back surface 32b of the light guide plate 32 on which the metal reflecting film 38 is formed is a repetition of the first inclined surface 42a and the second inclined surface 42b, but the inclination angle α1 of the first inclined surface 42a is the same as that of the second inclined surface 42b. It is extremely small compared to the inclination angle α2. Therefore, the total area of the second inclined surface 42b is sufficiently smaller than the total area of the first inclined surface 42a.

  The light guide plate 32 only needs to be transparent. Specifically, in addition to a transparent substrate such as glass or acrylic resin, heat resistance capable of depositing a metal thin film such as polycarbonate (PC), (PES), polyethylene naphthalate (PEN), etc. A transparent film can be used.

  The light guide plate 32 configured as described above is disposed so that the back surface 32 b, that is, the first inclined surface 42 a is parallel to the interference CF layer 22. That is, the light guide plate 32 is disposed with its upper surface 32a inclined at an angle α1, for example, 2 degrees with respect to the interference CF layer 22 and the array substrate 16 of the liquid crystal display panel 12, and on the light source side of the light guide plate 32. It is inclined so that the end portion is lowered.

  The inclination angle α1 of the light guide plate 32 is defined by the thickness of the spacer 44 inserted between the liquid crystal display panel 12 and the incident side end of the light guide plate 32. In order to prevent light absorption by the spacer 44, a reflective layer 46 is formed on the light guide plate 32 in a region where the spacer 44 is disposed.

In the second embodiment, other configurations are the same as those of the first embodiment described above.
In the backlight unit 14 configured as described above, the light incident on the light guide plate 32 from the LED 34 is reflected by the first inclined surface 42a, propagates through the light guide plate 32 while being collimated, and further the second The light is reflected by the inclined surface 42b and emitted from the upper surface 32a of the light guide plate 32 in a direction with an emission angle of 40 degrees or less. Of the light emitted from the light guide plate 32 in the vertical direction, the light that does not pass through the sub-pixel region of the interference CF layer 22 is the first inclined surface 42 a on which the non-absorption type interference CF layer 22 and the metal reflection film 38 are formed. Through multiple reflection between the sub-pixel regions, the light is emitted from the sub-pixel region having the same transmission wavelength region toward the liquid crystal display panel 12 (light recycling).

  According to the backlight unit 14 configured as described above and the liquid crystal display device 10 including the backlight unit 14, it is possible to separate the paths of the multiple reflections from the recycled light and the propagated light. It is possible to simultaneously suppress the spread of the directivity angle distribution and the vertical emission from the light guide plate. As a result, a backlight unit capable of improving light extraction efficiency and front luminance and a display device including the backlight unit can be obtained.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof. For example, the light source is not limited to the LED, and may be another light source.

10 ... Liquid crystal display device, 14 ... Backlight unit, 16 ... Array substrate,
18 ... counter plate, 20 ... liquid crystal layer, 22 ... interference color filter layer (color selection layer),
30 ... Support frame, 32 ... Light guide plate, 32a ... Upper surface, 32b ... Back surface,
32c ... incident surface, 34 ... LED (light source), 38 ... reflective film, 40 ... V groove (recess),
42a ... 1st inclined surface, 42b ... 2nd inclined surface, 44 ... Spacer

Claims (8)

A light guide plate having an exit surface, a back surface facing the exit surface and having a reflective film formed thereon, and an entrance surface intersecting the exit surface;
A light source that makes light incident on the light guide plate from the incident surface,
The back surface of the light guide plate is inclined with respect to the emission surface and has a plurality of first inclined surfaces that are longer with respect to the emission surface as the distance from the light source increases, and the first inclined surface is inclined with respect to the emission surface. A plurality of second inclined surfaces continuing on the side far from the light source,
An illumination device in which an angle formed by the second inclined surface with the exit surface is larger than an angle formed by the first inclined surface with the exit surface.   The back surface of the light guide plate has a plurality of wedge-shaped recesses respectively defined by the first inclined surface and the second inclined surface, and the recesses are in the width direction of the light guide plate parallel to the incident surface. The lighting device according to claim 1, wherein the lighting device extends over the light guide plate and is arranged side by side in the length direction of the light guide plate.   The lighting device according to claim 2, wherein the plurality of recesses are provided side by side, and a pitch of the recesses increases as the distance from the incident surface of the light guide plate increases.   The back surface of the light guide plate is formed to be inclined with respect to the emission surface, and the back surface of the light guide plate has a plurality of recesses respectively defined by the second inclined surface. Lighting equipment.   5. The lighting device according to claim 1, wherein an inclination angle of the first inclined surface is 2 to 20 degrees, and an inclination angle of the second inclined surface is 40 to 45 degrees. A lighting device according to any one of claims 1 to 5,
A liquid crystal display panel having a color selection layer provided facing the light exit surface of the light guide plate of the illumination device,
The liquid crystal display device in which the color selection layer and the first inclined surface of the illumination device are parallel.   The color selection layer has a plurality of sub-pixel regions that transmit light of different predetermined wavelengths and reflect light of a wavelength other than the predetermined wavelength, and the plurality of sub-pixel regions are provided side by side in a predetermined pattern. The liquid crystal display device according to claim 6.   The spacer provided between the edge part by the side of the light source of the light guide plate and the color selection layer, and a light reflection layer provided between the spacer and the light guide plate. Liquid crystal display device.

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