JP2006108045A - Lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system having a low environment risk, and emitting uniform flat light. <P>SOLUTION: In this lighting system 1, a plurality of light source units 10 at least having LED's 11 and light guide bodies 12 are arranged in one direction. The light guide body 12 receives light from a light entering side 12a and emits it from a main surface 12b. The light guide body 12 is formed in a wedge shape having the light entering side 12a as its base end. A plurality of the light source units 10 are arranged so that the base end K and the tip S of the light guide body 12 are alternated with each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lighting device.

  Conventionally, a surface illumination device using a cold cathode tube is generally used for a liquid crystal display device.

  FIG. 13 is a schematic perspective view for explaining the configuration of a liquid crystal display device 4 provided with a planar illumination device 300 using a conventional cold cathode tube.

  The liquid crystal display device 4 includes a planar illumination device 300 and a liquid crystal display panel 340. The planar illumination device 300 includes a plurality of cold cathode tubes 320 provided in parallel to each other. A reflector 310 is provided on the back surface (the lower side in FIG. 13) of the cold cathode tube 320. A scattering plate 330 is provided so as to face the reflection plate 310 with the cold cathode tube 320 interposed therebetween. The cold cathode tube 320 is filled with mercury vapor and argon gas.

  Mercury enclosed in the cold cathode tube 320 is a harmful substance to the human body and the environment, and its use is being restricted in recent years from the viewpoint of environmental protection. Under such a trend, research and development of planar lighting devices that are substantially free of mercury and other harmful substances and have low environmental risks are being actively conducted.

  For example, Patent Document 1 discloses a backlight unit (planar illumination device) using a light emitting diode (hereinafter referred to as “LED”) as a planar illumination device that does not substantially contain a harmful substance such as mercury. ing.

  FIG. 14 is a schematic perspective view of the backlight unit 5 described in Patent Document 1. As shown in FIG.

The backlight unit 5 includes a light guide 410 and three LEDs 420 (point light sources) provided on the side surfaces of the light guide 410. A hologram pattern 430 for emitting light emitted from the LED 420 to the emission surface 410a is formed on the lower surface of the light guide 410.
JP 2004-213025 A

  Since the light emitted from the LED 420, which is a point light source, spreads radially inside the light guide 410, the light emitted from the three LEDs 420 interfere with each other. Since more light is supplied to the portion c of the light guide body 410 where the light emitted from the plurality of LEDs 420 interferes, it becomes brighter than other portions (for example, the portion b in FIG. 14). On the other hand, since light from the LED 420 does not reach the portion a located near the side surface where the LED 420 of the light guide 410 is provided, it is darker than other portions (for example, the portion b in FIG. 14). A part of the light emitted from the LED 420 is absorbed by the light guide 410 when passing through the light guide 410. Therefore, the part II away from the LED 420 in the emission surface 410a is darker than the part I near the LED 420. Thus, the planar light emitted from the backlight unit 5 has spots, and there is a problem that uniform planar light cannot be obtained.

  This invention is made | formed in view of the point which concerns, The 1st objective is to implement | achieve the illuminating device with a low environmental risk. The second object is to realize an illumination device that emits uniform planar light.

  In the lighting device according to the present invention, a plurality of light source units each having at least a light emitting element and a light guide are arranged in one direction. The light guide receives light from the light emitting element from the light incident side surface and emits the light from the main surface. The light guide is formed in a wedge shape with the light incident side surface as a base end. The plurality of light source units are arranged so that the base end portion and the tip end portion of the light guide body are alternately arranged.

  In the illumination device according to the present invention, the light guide is formed in a wedge shape with the light incident side surface as the base end. In other words, since the angle formed by the pair of light reflecting side surfaces and the light incident side surfaces that are close to each other from the proximal end side to the distal end side of the light guide is an acute angle, the light reflection of the light emitted from the light emitting element is reflected. The incident angle to the side is large. Therefore, the reflectance by the light reflection side surface of the light emitted from the light emitting element is high. Therefore, most of the light incident on the light guide from the plurality of light emitting elements is emitted from the upper surface of the light guide, and the light of the light emitting elements provided in each of the light source units is effectively prevented from interfering with each other. can do.

  The plurality of light source units are arranged so that the base end portion and the tip end portion of the light guide are alternately arranged. According to this configuration, the base end portion close to the light emitting element and having high luminance and the tip end portion far from the light emitting element and having low luminance are alternately arranged. Since the light emitted from the base end portion close to the light emitting element and having a high luminance and the tip end portion far from the light emitting element and having a low luminance interfere with each other, the illumination device according to the present invention has a small overall luminance variation. As mentioned above, according to the illuminating device which concerns on this invention, uniform planar light is obtained.

  Moreover, in the illuminating device according to the present invention, a plurality of light source units are arranged with the light reflection side surfaces facing each other. For this reason, the dimension of an illuminating device can be easily adjusted by adjusting suitably the quantity of the light source unit to arrange.

  Moreover, since the illuminating device according to the present invention does not have a cathode tube or the like containing mercury, the environmental risk is low.

  In the illumination device according to the present invention, a gap may be formed between the light source units adjacent to each other. In other words, an air layer may be interposed between the light guides adjacent to each other. The light guide and the air layer have significantly different refractive indexes. Therefore, the light reflectance at the interface between the light guide and the air layer is high, and the rate at which the light emitted from the light emitting element is emitted from the light guide to the air layer is further reduced. Therefore, according to this structure, it can suppress effectively that each light of the light source unit arranged in multiple numbers mutually interferes, Therefore A more uniform planar light is obtained. Further, a light reflecting layer may be provided in the gap. The light reflecting layer may have a lower refractive index than the light guide.

  In the illumination device according to the present invention, a blaze (blazed pattern) may be formed on the upper surface of the light guide that emits the light. Here, the blaze refers to a plurality of fine grooves formed in parallel with each other at an angle in the light emitting direction from the light emitting element. The blaze is formed so that the angle at which light from the light emitting element is incident becomes small. Therefore, the reflectance at the upper surface where the blaze of the light emitted from the light emitting element is formed is small. Therefore, according to this configuration, the rate at which the light from the light emitting element is emitted from the light guide can be increased, so that higher luminance and lower power consumption can be realized. Further, the shape of the blaze near the light emitting element in the upper surface and the shape of the blaze far from the light emitting element may be different.

  In the illumination device according to the present invention, the wedge-shaped light guide has a pair of light reflecting side surfaces that are close to each other from the base end side toward the tip end side, and the pair of light reflecting side surfaces are mutually facing from the upper surface toward the lower surface. You may be close. According to this configuration, the incident angle of the light emitted from the light emitting element to the light reflection side surface becomes larger. Therefore, the emitted light from the light emitting element is reflected at a higher rate on the light reflecting side surface. Therefore, it is possible to more effectively suppress the light of the light emitting elements provided in each of the plurality of light source units arranged from interfering with each other, so that more uniform planar light can be obtained.

  The lighting device according to the present invention may further include a fixed substrate provided on the lower surface side facing the upper surface, and the plurality of light source units may be fixed to the fixed substrate. Moreover, the light source unit side surface of the fixed substrate may have light reflectivity. According to this configuration, it is possible to effectively prevent light from leaking from the lower surface of the light guide. Accordingly, the utilization efficiency of the light emitted from the light emitting element can be increased, so that high luminance and low power consumption can be realized.

  In the illumination device according to the present invention, the light emitting element may be a light emitting diode. Unlike a cold-cathode tube or the like, a light-emitting diode does not substantially contain an environmentally hazardous substance such as mercury, so that an environmental risk can be reduced. In addition, the light emitting diode has a long lifetime and low power consumption. Therefore, according to this configuration, a long product life and low power consumption can be realized.

  In the illumination device according to the present invention, at least two light source units selected from the plurality of light source units may emit light of different colors. The light emitting elements provided in the at least two light source units may have different applied current densities. According to this configuration, the color tone of the light emitted from the illumination device can be adjusted by appropriately adjusting the current density applied to the light emitting element.

  The illumination device according to the present invention may further include a scattering plate that covers the upper surface of the light source unit, and the scattering plate may diffuse and transmit light emitted from the light source unit. According to this configuration, light emitted from the light guides provided in each of the plurality of light source units is diffused by the diffusion plate, so that more uniform light can be obtained. In addition, when at least two light source units selected from the light source units emit light of different colors from each other, the emitted light of a plurality of colors is diffused and mixed by the diffusion plate, so that the light of uniform color tone Can be emitted.

  As described above, the lighting device according to the present invention has a low environmental risk. Moreover, the illumination device according to the present invention can emit uniform planar light.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  (Embodiment 1) FIG. 1 is a schematic front view of a surface illumination device 1 according to Embodiment 1 as viewed from the upper surface 12b side. For convenience of explanation, the scattering plate 30 is not drawn in FIG.

  FIG. 2 is a schematic side view of the planar illumination device 1.

  In the planar illumination device 1, a plurality of light source units 10 are arranged in a line in the X direction. A gap is formed between each of the plurality of light source units 10 arranged, and a light reflection layer 20 is provided in each of the gaps. Each of the plurality of light source units 10 includes an LED 11 and a wedge-shaped light guide 12 extending in the Y direction with the light incident side surface 12a as a base end. Base end portions and distal end portions of the plurality of light guide bodies 12 are alternately arranged on one surface. Specifically, the distal end portion and the proximal end portion of the adjacent light guide 12 are on one surface side of the planar illumination device 1. As shown in FIG. 2, a scattering plate 30 is provided on the upper surface 12 b side of the light guide 12, and a fixed substrate 40 is provided on the lower surface side of the light guide 12.

  FIG. 3 is a schematic perspective view of the light source unit 10.

  FIG. 4 is a schematic front view of the light source unit 10 as viewed from the upper surface 12b side.

  FIG. 5 is a schematic side view of the light source unit 10 as viewed from the light incident side surface 12a.

  The light guide 12 has a wedge shape with the light incident side surface 12a on which the LED 11 is provided as a base end, and has a pair of light reflecting side surfaces 12d that are close to each other from the base end side toward the front end side. Specifically, the light incident side surface 12a is formed in a rectangular shape, and the upper surface 12b and the lower surface 12c are formed in an acute isosceles triangle. The bottom angle of the upper surface 12b is preferably 60 degrees or more and less than 90 degrees. The upper surface 12b and the lower surface 12c are preferably congruent. The upper surface 12b and the lower surface 12c are parallel. The light reflecting side surface 12d is rectangular, and the pair of light reflecting side surfaces 12d are in contact with each other at the tip portion. Moreover, as shown in FIG. 1, the light reflection side surfaces 12d of the adjacent light guides 12 are opposed to each other. The upper surface 12b and the lower surface 12c may be formed in a trapezoidal shape.

  In the planar illumination device 1, light emitted from the LED 11 enters the light guide 12 from the light incident side surface 12a. Incident light is guided in the light guide 12 and emitted from the upper surface 12b. The light emitted from the upper surface 12b is further scattered by the scattering plate 30 and emitted from the planar illumination device 1 as uniform planar light.

  As shown in FIG. 3, each of the plurality of light source units 10 has an LED 11. The light guide 12 is formed in a wedge shape with the light incident side surface 12d as a base end. In other words, since the light incident side surface 12a and the light reflecting side surface 12d form an acute angle, the incident angle of the light emitted from the LED 11 to the light reflecting side surface 12d is large. The greater the angle of incidence on the light reflecting side surface 12d, the higher the reflectance at the light reflecting side surface 12d. Therefore, most of the light incident on the light guide 12 from the LED 11 is emitted from the upper surface 12b and hardly emitted from the light reflecting side surface 12d. Therefore, it can suppress effectively that the light from LED11 mutually interferes between the adjacent light source units 10. FIG.

  The transmittance of the light guide 12 of the light emitted from the LED 11 is not 100%, and part of the light emitted from the LED 11 is absorbed by the light guide 12 as it passes through the light guide 12. . Therefore, the portion of the upper surface 12b of the light guide 12 that is far from the LED 11 (tip portion S) has a lower luminance than the portion that is close to the LED 11 (base end portion K). In the planar illumination device 1, the light guide 12 is arranged such that the base end K having a relatively high luminance and the tip end S having a relatively low luminance are alternately arranged. Specifically, as shown in FIG. 1, the proximal end portion K of the light guide 12α and the distal end portion S of the light guide 12β adjacent thereto are on one surface side. Therefore, the planar illumination device 1 has less luminance variation as a whole. For example, there is no locally high luminance portion or low luminance portion. Further, the light with relatively low luminance emitted from the tip portions S arranged alternately and the light with relatively high luminance emitted from the base end portion K are diffused and mixed by the scattering plate 30. Therefore, according to the planar illumination device 1, there is no luminance unevenness and uniform light can be obtained.

  In the planar illumination device 1, the number of the light source units 10 to be arranged is not limited. Since the above-described effect can be obtained regardless of the number of the light source units 10 arranged, the planar illumination device 1 can obtain uniform planar light. Therefore, the size of the planar illumination device 1 (the length in the X direction in FIG. 1) can be easily adjusted by appropriately adjusting the quantity of the light source units 10 arranged. When adjusting the size of the planar illumination device 1 in the X direction, it is not necessary to change the design of the light source unit 10 itself.

  The planar illumination device 1 has a light reflection layer 20 provided in a gap between the light source units 10 adjacent to each other. The light reflecting layer 20 is in close contact with both the adjacent light guides 12. The light reflecting layer 20 is formed of a material having a lower refractive index than that of the light guide 12, and the light guide 12 and the light reflecting layer 20 have a significantly different refractive index. Therefore, the light reflectivity at the interface between the light reflection layer 20 and the adjacent light guide 12 is high, and effectively suppresses the light emitted from the LED 11 from being emitted from the light guide 12 to the light reflection layer 20. Can do. Therefore, it is possible to effectively suppress the interference of the lights of the LEDs 11 provided in each of the plurality of light source units 10 arranged, so that more uniform planar light can be obtained.

  In the first embodiment, the light reflecting layer 20 is formed of a material having a lower refractive index than that of the light guide 12, but the present invention is not limited to this. For example, it may be made of a metal material that reflects light. In the first embodiment, the light reflecting layer 20 is provided in the gap between the light source units 10 adjacent to each other, but the present invention is not limited to this. For example, an air layer may be interposed in the gap between the light source units 10 adjacent to each other.

  A blaze 13 is formed on the upper surface 12b of the light guide 12 so that the angle at which the light from the LED 11 enters the upper surface 12b is reduced. Therefore, the reflectance at the upper surface 12b on which the blaze 13 of the light emitted from the LED 11 is formed is small. Therefore, since the emission rate from the upper surface 12b of the light emitted from the LED 11 can be increased, higher luminance and lower power consumption can be realized. Moreover, you may make the blaze of a part near LED11 among the upper surface 12b, and the blaze of a part far from LED11 different. For example, a blaze having a long pitch may be formed in a portion near the LED 11 in the upper surface 12b, and a blaze having a short pitch may be formed in a far portion. Thereby, since the light reflectance of the part near LED11 among the upper surfaces 12b can be made lower than the light reflectance of a part far from LED11, a brightness nonuniformity can be reduced more.

  The fixed substrate 40 has the lower surfaces 12c of the plurality of light guides 12 fixed thereto. The light guide side surface 40a of the fixed substrate 40 has light reflectivity. For this reason, it can suppress effectively that light leaks from the lower surface 12c of a light guide. Therefore, since the utilization efficiency of the light emitted from the LED 11 can be increased, high luminance and low power consumption can be realized. Examples of a method for fixing the light guide 12 to the fixed substrate 40 include a method in which the light guide 12 and the fixed substrate 40 are bonded and fixed with a double-sided tape.

  The LED 11 as the light emitting element substantially does not contain an environmentally hazardous substance such as mercury. Therefore, environmental risk can be reduced. Further, the LED 11 has low power consumption and a long life. Therefore, the planar lighting device 1 with low power consumption and a long product life can be realized. In Embodiment 1, LEDs are used as light emitting elements, but the present invention is not limited to this configuration. For example, an organic electroluminescence element or an inorganic electroluminescence element may be used as the light emitting element. In the first embodiment, one LED 11 is provided as a light emitting element, but the light source unit 10 may have two or more LEDs. Since the light emission luminance of each light source unit 10 can be increased, the high-luminance planar illumination device 1 can be realized.

  Next, the material of each member which comprises the planar illuminating device 1 is demonstrated. In addition, the material of the following member is only an illustration, Comprising: This invention is not limited to these at all. Examples of the material of the LED 11 include GaP, GaAsP, GaAlAs, InGaAlP, GaN, ZnSe, ZnTe, ZnS, and SiC. A mixture of these materials may be used. Examples of the material of the light guide 12 include acrylic, polymethyl methacrylate (PMMA), amorphous polyolefin, and polycarbonate. Examples of the material of the light reflecting layer 20 include metal materials such as aluminum (Al) and silver (Ag), and low refractive index resins such as. The scattering plate 30 can be constituted by a sheet or the like obtained by coating a polycarbonate or polyester base film with a resin mixed with transparent beads. The fixed substrate 40 can be composed of a glass substrate or the like coated with aluminum (Al), silver (Ag), or the like using a sputtering method or the like.

  FIG. 6 is a schematic side view of a liquid crystal display device provided with the planar illumination device 1.

  The liquid crystal display device includes a planar illumination device 1 and a liquid crystal display panel 50. The liquid crystal display panel 50 is sandwiched between two polarizing plates 51 and 52. As described above, the planar illumination device 1 can emit uniform planar light. Accordingly, since the uniform planar light is incident on the liquid crystal display panel 50, the liquid crystal display device can display a uniform image with no spots.

  (Embodiment 2) FIG. 7 is a schematic front view of a surface illumination device 2 according to Embodiment 2 as viewed from the light exit surface side.

  FIG. 8 is a schematic side view of the planar illumination device 2.

  In the planar illumination device 2, a plurality of light source units 110 are arranged in a line in the X direction. A gap is formed between each of the plurality of light source units 110 arranged, and a light reflection layer 120 is provided in each of the gaps. Each of the plurality of light source units 110 includes an LED 111 and a wedge-shaped light guide 112 having a light incident side surface 12a as a base end and a long wedge shape in the Y direction. The proximal end portions and the distal end portions of the plurality of light guides 112 are alternated. Specifically, the distal end portion and the proximal end portion of the adjacent light guide 12 are on one surface side of the planar illumination device 2. Further, as shown in FIG. 8, a scattering plate 130 is provided on the upper side of the light guide 112, and a fixed substrate 140 is provided on the lower side of the light guide 112. Individual configurations and shapes of the plurality of light source units 110 are the same as those of the light source unit 10 according to the first embodiment. The plurality of arranged light source units 110 includes a light source unit 110R including an LED 111R that emits R (red) light, a light source unit 110G that includes an LED 111G that emits G (green) light, and B (blue) light. And a light source unit 110B including an LED 111B that emits light. The light source units 110R, 110G, and 110B are arranged in this order. Here, differences from the planar illumination device 1 according to the first embodiment, specifically, the light source units 110R, 110G, and 110B will be described in detail.

  In the surface illumination device 2, R (red), G (green), and B (blue) light emitted from the light source units 110R, 110G, and 110B is diffused and mixed by the scattering plate 130, and has a uniform color surface. Is emitted as a light beam. The color tone of the light emitted from the planar illumination device 2 is determined by the intensity of the light emitted from each of the light source units 110R, 110G, and 110B. For example, when the intensity of R light emitted from the light source unit 110R is increased by increasing the intensity of light emitted from the LED 111R, emitted light having a more reddish color tone is obtained. The light emitted from the LED 111 becomes stronger as the applied current density increases. Therefore, the color tone of the light emitted from the planar illumination device 2 can be adjusted by adjusting the current density applied to the LEDs 111R, 111G, and 111B. According to this color tone adjustment method, the color tone of light emitted from the planar illumination device 2 can be easily adjusted without changing the color tone of the LED 111.

  In the second embodiment, the planar illumination device 2 is configured by the three types of light source units 110, but the present invention is not limited to this. For example, the planar illumination device 2 may be configured by four or more types of light source units 110.

  (Third Embodiment) FIG. 9 is a schematic side view of a planar illumination device 3 according to a third embodiment.

  In the planar illumination device 3, a plurality of light source units 210 are arranged in one direction. A gap 220 is formed between each of the plurality of light source units 210 arranged. Each of the plurality of light source units 210 includes an LED 211 and a wedge-shaped light guide 212. The proximal end portions and the distal end portions of the plurality of light guides 212 are alternated. Specifically, the distal end portion and the proximal end portion of the adjacent light guide 212 are on one surface side of the planar illumination device 3. A scattering plate 230 is provided above the light guide 212, and a fixed substrate 240 is provided below the light guide 212.

  FIG. 10 is a schematic perspective view of the light source unit 210.

  FIG. 11 is a schematic side view of the light source unit 210 as viewed from the light incident side surface 212a side.

  The light guide 212 has a wedge shape with the light incident side surface 212a provided with the LEDs 211 as a base end, and has a pair of light reflecting side surfaces 212d that are close to each other from the base end side toward the front end side. The pair of light reflecting side surfaces 212d are close to each other from the upper surface 212b toward the lower surface 212c. Specifically, the light incident side surface 212a is formed in a twisted quadrilateral. The upper surface 212b and the lower surface 212c are formed in an acute isosceles triangle. The apex angle of the upper surface 212b is larger than the apex angle of the lower surface 212c. The base angle of the upper surface 212b is preferably 60 degrees or more and less than 90 degrees. The upper surface 212b and the lower surface 212c may be formed in a trapezoidal shape. In this case, the length of the bottom side of the upper surface 212b is longer than the length of the bottom side of the lower surface 212c. The upper surface 212b and the lower surface 212c are preferably similar. There may be no lower surface 212c, and a pair of light reflecting surfaces 212d may be in contact with each other. In this case, the light incident side surface 212a is triangular. The light reflection side surfaces 212d of the adjacent light guides 12 face each other.

  In the planar illumination device 3, the light guide 212 is formed in a wedge shape with the light incident side surface 212a as a base end, and the pair of light reflecting side surfaces 212d are close to each other from the upper surface 212b toward the lower surface 212c. In other words, the angle formed by the light incident side surface 212a and the light reflecting side surface 212d is an acute angle, and the angle formed by the lower surface 212c and the light reflecting side surface 212d is an obtuse angle. Therefore, the light source unit 210 according to the third embodiment has a larger incident angle to the light reflecting side surface 212d of the light emitted from the light source 211 than the light source unit 10 according to the first embodiment, and the light emitted from the LED 211 is light. The reflectance at the reflecting side surface 212d is even greater. Therefore, it is possible to more effectively prevent light from the LED 211 from exiting from the light reflecting side surface 212d, and it is possible to more effectively prevent light from the LED 211 from interfering with each other. As described above, according to the planar illumination device 3, more uniform planar light can be obtained.

  Also, the pair of light reflecting side surfaces 212d are close to each other from the upper surface 212b to the lower surface 212c, and as shown in FIG. Intervenes. Therefore, the light reflectance at the interface between the light guide 212 and the air layer is high, and the rate at which the light emitted from the LED 211 is emitted from the light guide 212 to the air layer can be further reduced. Therefore, in this planar illumination device 3, it is possible to effectively prevent the light of each of the light source units 210 arranged in a plurality from interfering with each other, so that more uniform planar light can be obtained.

  FIG. 12 is a schematic side view of a liquid crystal display device provided with the planar illumination device 3.

  This liquid crystal display device includes a planar illumination device 3 and a liquid crystal display panel 250. The liquid crystal display panel 250 is sandwiched between polarizing plates 251 and 252. As described above, the planar illumination device 3 can emit uniform planar light. Therefore, uniform planar light is incident on the liquid crystal display panel 250 provided on the planar illumination device 3. Therefore, this liquid crystal display device can display a uniform image without luminance spots.

  As described above, the lighting device according to the present invention has low environmental risk and can emit uniform planar light. Therefore, it is useful as a backlight of a liquid crystal display device.

It is the schematic front view seen from the upper surface 12b side of the planar illuminating device 1 which concerns on Embodiment 1. FIG. 1 is a schematic side view of a planar illumination device 1. FIG. 1 is a schematic perspective view of a light source unit 10. FIG. FIG. 3 is a schematic front view of the light source unit 10 as viewed from the upper surface 12b side. FIG. 3 is a schematic side view of the light source unit 10 as viewed from the light incident side surface 12a side. 1 is a schematic side view of a liquid crystal display device provided with a planar illumination device 1. FIG. It is the schematic front view seen from the light-projection surface side of the planar illuminating device 2 which concerns on Embodiment 2. FIG. It is a schematic side view of the planar illumination device 2. It is a schematic perspective view of the light source unit 210 which the planar illuminating device 3 which concerns on Embodiment 3 has. It is the schematic side view seen from the light-incident side surface 212a side of the light source unit 210. It is a schematic side view of the planar illumination device 3. 3 is a schematic side view of a liquid crystal display device including a planar illumination device 3. FIG. It is a schematic perspective view for demonstrating the structure of the planar illuminating device using the conventional cold cathode tube. It is a schematic perspective view of the backlight unit 5 described in Patent Document 1.

Explanation of symbols

1, 2, 3, 300 Planar illumination device
4 Liquid crystal display device
5 Backlight unit
10, 110, 210 Light source unit
11, 111, 211, 420 LED
12, 112, 212, 410 Light guide
13, 113, 213 Blaze
20, 120 Light reflecting layer
30, 130, 230, 330 Scattering plate
40, 140, 240 Fixed substrate
50, 250, 340 LCD panel
51, 52, 251, 252 Polarizing plate 310 Reflecting plate 320 Cold cathode tube 430 Hologram pattern

Claims (12)

A lighting device in which a plurality of light source units each having at least a light emitting element and a light guide are arranged in one direction,
The light guide receives light from the light emitting element from a light incident side surface and emits the light from a main surface;
The light guide is formed in a wedge shape with the light incident side surface as a base end,
The illuminating device in which the plurality of light source units are arranged so that a base end portion and a tip end portion of the light guide body are alternately arranged. The lighting device according to claim 1,
A lighting device in which a gap is formed between the light source units adjacent to each other. The lighting device according to claim 2,
A lighting device in which a light reflecting layer is provided in the gap. The lighting device according to claim 3,
The lighting device in which the light reflection layer in the previous period has a lower refractive index than the light guide. The lighting device according to claim 1,
A lighting device in which a blaze is formed on the upper surface of the light guide that emits the light. The lighting device according to claim 1,
The wedge-shaped light guide has a pair of light reflecting side surfaces that are close to each other from the proximal side toward the distal side,
The pair of light reflecting side surfaces are close to each other from the upper surface toward the lower surface. The lighting device according to claim 1,
Further comprising a fixed substrate provided on the lower surface side of the light guide,
The lighting device in which the plurality of light source units are fixed to the fixed substrate. The lighting device according to claim 7,
The light source unit side surface of the fixed substrate is a lighting device having light reflectivity. The lighting device according to claim 1,
The lighting device, wherein the light emitting element is a light emitting diode. The lighting device according to claim 1,
An illuminating device in which at least two light source units selected from the plurality of light source units emit light of different colors. The lighting device according to claim 10,
The light emitting device provided in the at least two light source units is a lighting device in which applied current densities are different from each other. The lighting device according to claim 1,
A scattering plate covering the upper surface of the light source unit;
The scattering plate is an illumination device that diffuses and transmits light emitted from the light source unit.

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