JP2008192395A - Lighting device, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a flat lighting device used in a liquid crystal display device thin and lightweight, and to inexpensively constitute it. <P>SOLUTION: In this lighting device 1, a plurality of surface light emitting plates 2, in each of which a light guide part 3 and a light source part 4 installed at the end part of the light guide part 3 are integrally formed, are arranged in a planar shape, the light source part 4 of the surface light emitting plate 2 and the light guide part 3 of the other adjoining surface light emitting plate 2 are formed so as to overlap each other on a plane, and light having uniform luminance can be irradiated to the upper part of the surface light emitting plate 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flat backlight device used for illuminating a liquid crystal display device or the like from the back and a liquid crystal display device using the same.

  Liquid crystal display devices are widely used. The liquid crystal display device includes a liquid crystal display panel and a flat backlight provided on the back surface of the liquid crystal display panel. In recent years, with the increase in size of liquid crystal display panels, the size of flat backlights has also been increasing. The functions required for a large flat backlight include high brightness and uniform brightness over the entire light emitting surface, thin and lightweight, and suppression of increase in manufacturing costs. it can. In particular, as the size of the components increases, the assembly line becomes larger, equipment investment increases, and the occurrence of defective products is a major factor in increasing manufacturing costs.

  FIG. 8 is a cross-sectional view of a conventionally known liquid crystal display device 100 (see, for example, Patent Document 1). A backlight 107 is installed below the liquid crystal display panel 105. The backlight 107 includes an outer case 106, two light sources 101a and 101b housed in the outer case 106, two divided light guides 104a and 104b, outer peripheries of the light sources 101a and 101b, and light guides 104a and 104b. And a diffusion plate 103 that diffuses light emitted from the light guides 104a and 104b in a predetermined direction. In the case of this example, in order to cope with an increase in the size of the backlight, the light sources 101a and 101b are arranged on the left and right sides, the light guide is divided at the center, and the left light guide 104a is separated from the left light source 101a. Light is guided and guided to the right light guide 104b from the right light source 101b.

FIG. 9 is an exploded perspective view of a conventionally known surface light source device 110 (see, for example, Patent Document 2). In the surface light source device 110, a divided optical film is sandwiched between two diffusion plates 112 and 115. That is, the sub-selective reflective film 113 divided into four and the sub-reflective polarizing film 114 divided into four. A plurality of light sources 111 housed in a frame 116 are arranged below the diffusion plate 112. In this example, the sub selective reflection type film 113 and the sub reflection type polarizing film 114 are divided so as to cope with an increase in the size of the surface light source device 110.
Japanese Patent Laid-Open No. 5-158035 JP 2006-120584 A

  However, in the backlight 107 shown in FIG. 8, the light source 101 is disposed on the side surface portion of the exterior case 106 and light is introduced from the end portion of the light guide body 104. Therefore, there has been a problem that the amount of light becomes insufficient as the backlight 107 becomes larger. In addition, as the light guide 104 is increased in size, the light guide 104 can be physically divided into two or more parts. However, light is reflected at the boundary between the divided light guides, and light with uniform luminance is obtained. There is a problem that it is difficult to emit light. In addition, each light guide plate can be bonded by preventing reflection at the boundary. However, when defects such as scratches and dirt are found, the entire light guide plate must be replaced. There was a problem that it was not possible to make use of the advantage of dividing.

  In the surface light source device 110 shown in FIG. 9, a plurality of light sources 111 are attached to the frame 116 and installed below the diffusion plate 112. A cold cathode fluorescent lamp (hereinafter referred to as CCFL) is used as the light source 111 of this type of large surface emitting source. Many CCFLs are used to increase the brightness of light emitted from the diffusion film 115 and to make the brightness uniform over the entire surface. For this reason, there is a problem that the frame 116 for storing the CCFL becomes thick and heavy. In addition, a CCFL corresponding to the size of the light emitting surface has to be created, and there is a problem that it is difficult to make components common.

  In recent years, in a large-sized liquid crystal display device, an area control system that can adjust the luminance of a light emitting source for each region may be employed. In this method, the amount of light of the backlight is dimmed for each area of the backlight according to the display screen of the liquid crystal display device. The liquid crystal display device 100 of FIG. 8 can control the luminance of the left and right regions at most, and the surface light source device of FIG. 9 can control the luminance of the vertical or horizontal region, both of which can be dimmed. There was a problem that the area was small. Moreover, when using CCFL as a light source, since it was necessary to provide light control by providing an inverter circuit in each CCFL, there existed a subject that a component increased and a weight and volume increased.

  In order to solve the above-described problems, the illumination device of the present invention includes a plurality of planar light emitting plates in which a light guide unit and a light source unit installed at an end of the light guide unit are configured in a planar manner. In the illuminating device, the light source part of the surface light emitting plate and the light guide part of another adjacent surface light emitting plate are arranged so as to overlap in a plane.

  The light guide part has a wedge-shaped cross section, the light source part of the surface light-emitting plate is installed on the thick part of the wedge shape, and the light guide part of the other adjacent surface light-emitting plate is the wedge-shaped part. The thin-walled portion is arranged so as to overlap the light source portion of the surface light emitting plate.

  The angle between the upper surface and the lower surface forming a wedge shape is 1 ° to 10 °.

  In a region where the surface light emitting plate and another surface light emitting plate adjacent to each other overlap in a planar manner, a stepped portion is formed on the upper surface of the surface light emitting plate, and an end of another surface light emitting plate adjacent to the stepped portion is installed. Then, light is introduced from another adjacent surface light emitting plate to the surface light emitting plate.

  Further, a reflecting surface is formed on the surface of the light source portion of the surface light emitting plate. The surface of the light guide is a prism surface having a light diffusion function. This prism surface is configured such that a large number of V grooves are formed on the surface of the light guide. Furthermore, the angle between the surface of the light guide and the inclined surface of the V-groove was 0.25 ° to 3.0 °, and the pitch of the V-groove was 0.25 μm to 200 μm.

  In addition, the light source unit includes a light emitting diode and a heat radiating member for radiating heat from the light emitting diode. The light emitting diode is a blue light emitting diode, and a red phosphor and a green phosphor are provided in the light source section. In addition, a reflection plate disposed under the surface light-emitting plate and a frame disposed under the reflection plate are further provided, and a heat dissipation member is connected to the frame so that heat from the light-emitting diode is radiated to the frame. .

  In addition, the liquid crystal display device of the present invention includes a lighting device and a liquid crystal display element disposed on the lighting device, and the lighting device includes a light guide unit and a light source unit installed at an end thereof integrally. A plurality of configured surface light emitting plates are arranged in a planar shape, and a light source portion of a surface light emitting plate and a light guide portion of another adjacent surface light emitting plate are arranged to overlap each other in a planar manner.

  The liquid crystal display device according to the present invention includes an image data output circuit that outputs image data to the liquid crystal display element, and an illumination drive circuit for driving the illumination device, and the illumination drive circuit inputs the image data. Thus, the light source portions of the plurality of surface light emitting plates are controlled according to the image data.

  According to the illuminating device of the present invention, a plurality of surface light emitting plates each integrally configured with a light guide and a light source unit are arranged in a planar shape, and the light source unit and the light guide unit overlap each other in the adjacent surface light emitting plate. Therefore, even if one surface light emitting plate becomes defective, it is only necessary to replace the defective surface light emitting plate, and it is not necessary to replace the entire light guide part. Has the advantage of being able to.

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

<Example 1>
FIG. 1 shows a first embodiment of a lighting device according to the present invention and is a diagram for explaining a basic mode of the lighting device. FIG. 1A is a perspective view of an illuminating device including four surface light-emitting plates, and FIG. 1B is a perspective view showing a state in which the surface light-emitting plates are separated, and FIG. ) Is a cross-sectional view of two connected surface light emitting plates. The same part or the part representing the same function is denoted by the same reference numeral.

  As shown to Fig.1 (a), the illuminating device 1 is comprised by the four surface emitting plates 2a, 2b, 2c, 2d arranged in a plane. As shown in FIG.1 (b), the surface emitting plates 2a-2d are arrange | positioned so that isolation | separation is possible. The surface light emitting plates 2a to 2d have basically the same shape and configuration. As shown in FIG. 1C, the surface light emitting plate 2a is integrally formed of a light guide portion 3a and a light source portion 4a. The light source portion 4a of the surface light emitting plate 2a and the light guide portion 3b of the surface light emitting plate 2b are arranged so as to overlap each other.

  Here, the light emitted from the light source unit 4a is transmitted between the upper surface 6a and the lower surface 5a of the light guide unit 3a, and diffuses over the entire surface of the plate-shaped light guide unit 3a. The same applies to the surface light emitting plate 2b. Further, the surface light emitting plate 2a and the surface light emitting plate 2b are in contact with each other at the inclined surface 8a and the inclined surface 7b. Therefore, the light that has transmitted through the light guide portion 3b of the surface light emitting plate 2b and reached the inclined surface 7b can be incident from the inclined surface 8a of the surface light emitting plate 2a. As a result, it is possible to reduce luminance unevenness between the vicinity of the upper part of the light source 4a of the surface light emitting plate 2a and the front end of the light guide 3b of the surface light emitting plate 2b. Further, a light scattering surface or a prism surface can be formed on the inclined surfaces 7a and 7b and the lower surfaces 5a and 5b of the light guide portions 3a and 3b. Alternatively, a light scattering plate can be installed below the inclined surfaces 7a and 7b and the lower surfaces 5a and 5b to scatter light upward. In addition, the bent portion where the inclined surfaces 7a, 7b and the lower surfaces 5a, 5b intersect can be formed in a smooth arc shape to reduce uneven brightness of light emitted from the upper surfaces 6a, 6b.

  As a light source embedded in the light source unit 4a (4b) or attached to the light guide unit 3a (3b), a light emitting diode, EL, or other small light source can be used. As the light guide 3, a transparent synthetic resin such as polycarbonate resin, acrylic resin or ZEONOR film (registered trademark), or an inorganic material such as glass can be used. The light guide 3 can be formed by injection molding of a transparent synthetic resin. Further, an adhesive connecting material having a predetermined refractive index can be filled between the inclined surface 8a of the surface light emitting plate 2a and the inclined surface 7b of the surface light emitting plate 2b. Thereby, the reflection loss of the light which enters into the light guide part 3a from the light guide part 3b can reduce, and the brightness | luminance nonuniformity which is easy to generate | occur | produce in a boundary area | region can be suppressed.

  In this way, by arranging the light source part of the surface light emitting plate and the light guide part of the adjacent surface light emitting plate so as to overlap each other, it is possible to configure an illuminating device that eliminates uneven brightness and light gaps. In addition, since the surface light-emitting plates may be arranged in accordance with the size of the device that requires illumination, the design and manufacturing process of members and the like can be reduced. Further, when scratches or dirt adhere to some of the surface light emitting plates and need to be replaced, it is only necessary to replace the surface light emitting plate with the scratches or dirt attached. Thereby, a manufacturing yield can be improved and manufacture and repair can be performed at low cost.

<Example 2>
FIG. 2 shows Example 2 of the illuminating device according to the present invention, FIG. 2 (a) is a sectional view of the illuminating device, and FIG. 2 (b) is a top view. The same portions or portions having the same function are denoted by the same reference numerals.

  As shown in FIG. 2A, the light guides 3a and 3b have a wedge shape. The light guide 3a (3b) and the light source 4a (4b) are integrally formed, and a step surface 10a is formed in the vicinity of the boundary between the light guide 3b and the light source 4a. The light source parts 4a and 4b are installed on the wedge-shaped thick part. Further, the wedge-shaped thin portion is arranged so as to overlap the light source portion of the adjacent surface light emitting plate. That is, the light source unit 4a of the surface light emitting plate 2a and the light guide unit 3b of the surface light emitting plate 2b are arranged so as to overlap each other. Further, the end surface 9a of the surface light emitting plate 2b is in contact with the stepped surface 10a of the surface light emitting plate 2a. Thereby, the light which propagated the light guide part 3b of the surface light-emitting plate 2b injects into the surface light-emitting plate 2a via the level | step difference surface 10a. Thereby, uneven brightness in the vicinity of the step surface can be reduced.

  By making the light guide portion into such a wedge shape, there are no bent portions on the lower surfaces 5a and 5b and the upper surfaces 6a and 6b of the light guide portions 3a and 3b, and uneven brightness of the emitted light emitted from the surface light emitting plates 2a and 2b. Can be reduced. In addition, as described in the first embodiment, a connecting material having a predetermined refractive index is filled between the step surface 10a and the end surface 9b to reduce reflection loss at the boundary portion and reduce the occurrence of luminance unevenness. it can. Further, the step surfaces 10a and 10b and the end surfaces 9a and 9b do not have to be perpendicular to the upper surfaces 6a and 6b, and may be formed to be inclined.

  The angle θ between the wedge-shaped lower surface 5a and the upper surface 6a is preferably set in the range of 1 ° to 10 °. In this embodiment, the surface light emitting plates 2a and 2b are assumed to be units of 5 inches to 10 inches. For this reason, when the angle θ is 10 ° or more, the thickness of the light guide portions 3a and 3b is thick, and when the angle θ is less than 1 °, the height of the step surfaces 10a and 10b is large and the thickness of the light source portions 4a and 4b. This is because the thickness becomes thinner.

<Example 3>
FIG. 3 shows the irradiation apparatus of this embodiment. FIG. 3A is a sectional view of the surface light emitting plate, and FIG. 3B is a partially enlarged view thereof. The same part or part representing the same function is denoted by the same part number.

  As shown in FIG. 3A, the light guide 3 of the surface light emitting plate 2 has a wedge shape, and the lower surface 5 is subjected to light scattering treatment. The light scattering treatment may be roughened by sandblasting or the like, or irregularities may be formed on the surface by etching or printing. Further, when the light guide 3 is formed by injection molding, a light scattering surface or a prism surface may be formed at the same time. In addition, you may form a light-scattering surface in the upper surfaces 6a and 6b of the light guide parts 3a and 3b.

  FIG. 3B is a partial enlarged cross-sectional view of the light guide portion 3 and shows a state in which a V-groove is formed on the lower surface 5. The V groove is formed in a direction perpendicular to the light incident direction. That is, a V-groove is formed in a direction perpendicular to the paper surface. The pitch P of the V grooves is preferably 50 μm to 200 μm. The width L of the bottom of the V groove is preferably 40 μm to 150 μm. In addition, it is preferable that an angle φ formed by the inclined surface of the V groove and the base 11 of the V groove is 0.25 ° to 3.0 °. This is because if the pitch P is 50 μm or less, the manufacturing cost is high, and if it exceeds 200 μm, the human eye can identify the V-groove. Further, when the angle φ is smaller than 0.25 °, the light scattering efficiency is lowered, and when φ is 3.0 ° or more, the light is transmitted between the region near the light source unit 4 and the region far from the light source unit 4. This is because the difference in scattering intensity increases and uneven brightness occurs.

  The V-groove can also be formed on the upper surface 6 of the light guide 3. In this case, the V groove formed on the upper surface 6 is set in a direction perpendicular to the direction of the V groove formed on the lower surface 5. This is to prevent the occurrence of defects such as moire fringes due to the V grooves formed on the lower surface 5 and the upper surface 6. When V grooves are formed on both the lower surface 5 and the upper surface 6, the V grooves may be formed so that the V groove directions are perpendicular to each other, and the direction of incident light is not limited.

<Example 4>
FIG. 4 shows a fourth embodiment of the lighting device according to the present invention, and FIG. 4 (a) is a perspective view showing a state in which two surface light emitting plates 2a and 2b are connected to each other, and FIG. These are the fragmentary sectional views which expanded the connection part. The same parts or parts having the same function are denoted by the same reference numerals.

  In FIG. 4A, the light guide portion 3a (3b) has a wedge shape, and the light source portion 4a (4b) is integrally formed on the thick portion. The thin part of the light guide part 3a (3b) is placed so as to overlap the light source part of the adjacent surface emitting plate. The upper surface 6a and the upper surface 6b of the surface light emitting plates adjacent to each other constitute substantially the same plane. The light source unit 4a (4b) includes an extension part 15a (15b) extending from the light guide part 3a (3b), a light source 14a (14b) installed in the extension part 15a (15b), and a light source 14a ( 14b) includes a flexible printed circuit board (hereinafter referred to as FPC) 12a (12b) for supplying power, and a heat radiating member 13a (13b) for radiating heat generated from the light source 14a (14b). Yes. V-grooves orthogonal to each other are formed on the lower surface 5a (5b) and the upper surface 6a (6b) of the light guide 3a (3b). The heat radiating member 13a (13b) and the FPC 12a (12b) or the light source 14a (14b) are bonded to each other by a heat conductive adhesive (not shown).

  The light sources 14a and 14b use blue light emitting diodes. A first phosphor layer 16a (16b) is formed around the light source 14a (14b). A groove-shaped second phosphor layer 17a is formed in the extending portion 15a (15b) in front of the first phosphor layer 16a. It is provided to obtain fluorescence of light emitted from the light source 14a. In the present embodiment, a blue light emitting diode is used as the light source 14a, the first phosphor layer 16 is filled with a red phosphor, and the second phosphor layer is filled with a green phosphor. A mixed resin in which a phosphor is mixed with a resin such as silicon, epoxy, or acrylic is formed and filled. At the time of filling, a gap is not formed between the extending portion 15a (15b) and the mixed resin. In addition, a light-transmitting material having a refractive index different from that of a material such as silica or acrylic may be dispersed and added to the mixed resin to diffuse incident light or fluorescence.

  Blue light emitted from the blue light emitting diode, red fluorescence is emitted from the blue light, and green fluorescence is further emitted. Thereby, white light with high color rendering properties can be obtained. Further, since the light emitting diode and the phosphor layer are configured to be embedded in the extending portion 15a (15b) extending from the light guide portion 3a (3b), the thickness of the surface light emitting plate 2a (2b) can be reduced. it can. Even if the surface area of the illuminating device 1 is increased by using many surface light emitting plates 2a (2b), there is an advantage that the thickness of the illuminating device 1 does not increase. Further, since each surface light emitting plate 2a (2b) has a light source, there is an advantage that even when the area of the illumination device 1 is increased, a uniform and high luminance illumination device can be configured. In addition, even when the area is increased, there is an advantage that it is not necessary to increase the size of each member, the manufacturing and assembly lines, and the members can be shared.

  The heat dissipating member 13a (13b) transmits heat generated by the light source 14a (14b) to the outside, and the light sources 14a and 14b are prevented from being heated to lower the luminous efficiency. As a result, when a blue light-emitting diode is used as the light source 14a, a large current can flow through the blue light-emitting diode, and high-luminance light emission can be obtained. Further, since white light is obtained by additively mixing red, green and blue wavelengths, the color rendering property is excellent. Moreover, since a light emitting diode is used, it has a long life and excellent temperature characteristics as compared with CCFLs and white LEDs conventionally used. The first phosphor layer 16a is filled with a red phosphor and the second phosphor layer 17a is filled with a green phosphor. Instead, the first phosphor layer 16a is filled with a green phosphor. The two phosphor layers 17a can be filled with a red phosphor. However, when the second phosphor layer is filled with a red phosphor, the red phosphor emits light by green light as well as blue light, and absorbs green, so that it is difficult to adjust the color balance. Therefore, it is preferable to fill the first phosphor layer with a red phosphor and the second phosphor layer with a green phosphor.

As the red phosphor, a phosphor such as CaS: Eu or SrS: Eu doped with europium in a sulfide, or nitride-based CaSiN ₂ : Eu or CaAlSiN ₃ : Eu can be used. As the green phosphor, a silicate of (Ba, Sr) SiO ₄ : Eu, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce, or a sulfide phosphor such as SrGa ₂ S ₄ can be used. In addition to the above, (Ca, Sr) ₂ Si ₅ N ₈ : Eu or the like can be used as the red phosphor. Also, as the green _{phosphor, Y3 (Ai, Ga) 5} O 12: Ce, Sr-SiON: it can be used Eu and the like. In addition, the sulfide-based phosphor has a characteristic that it is vulnerable to moisture. Therefore, it is preferable to apply a coating such as a transparent oxide film on the surface of the phosphor particles, and to use an epoxy resin having a low moisture permeability as the mixed resin.

In the above embodiment, white light was obtained using a red light emitting diode and a green light emitting phosphor with a blue light emitting diode as a light source. Instead, a near ultraviolet light emitting diode was used as each of the light sources 14a and 14b. A third phosphor layer filled with blue phosphor may be formed. In this case, as the red phosphor, Y ₂ O ₂ S: Eu, La ₂ O ₂ S: Eu, LiW ₂ O8: Eu, Sm, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, Mn, Ba ₃ MgSi ₂ O ₈ : Eu, Mn and the like can be used. As the green phosphor, ZnS: Cu, Al, BaMgAl ₁₀ O ₁₇ : Eu, Mn, SrAl ₂ O ₄ : Eu, or the like can be used. As the blue phosphor, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu, (Sr, Ba) ₃ MgSi ₂ O ₈ : Eu, etc. Can be used. Preferably, Ba ₃ MgSi ₂ O ₈ : Eu, Mn is used as the red phosphor, SrAl ₂ O ₄ : Eu is used as the green phosphor, and (Sr, Ba) ₃ MgSi ₂ O ₈ : Eu is used as the blue phosphor. .

<Example 5>
FIG. 5 is an exploded perspective view of the lighting device 1 configured by using six surface light emitting plates 2a shown in the fourth embodiment. The same reference numerals are assigned to the same parts or parts having the same function. In FIG. 5, the light emitting surface is composed of six surface light emitting plates 2a to 2h. A reflector 19 is installed below the surface light emitting plates 2a to 2h, and a frame 18 is installed below the reflector 19. A diffusion plate 20 is disposed above the surface light emitting plates 2 a to 2 h, and the periphery is fixed by a frame 21. A plurality of holes are formed in the frame 18 and penetrate the heat radiating member 13a of the light source unit 4a. And the heat radiating member 13a and the flame | frame 18 are adhere | attached, and the flame | frame 18 is functioned as a heat radiating fin. Thereby, the heat generated by the light source 14a of the light source unit 4a can be efficiently released. When a light emitting diode is used as the light source 14a, it is possible to suppress the temperature rise of the light emitting diode, and a high current can be realized by flowing a large current.

  In FIG. 5, eight surface light-emitting plates 2a to 2h are adjacent to each other as a surface light source 50, but the number of surface light-emitting plates 2a to 2h can be increased or decreased. Moreover, the brightness | luminance of each surface emitting plate 2a-2h can be adjusted independently by providing a drive power supply in parallel with each surface emitting plate 2a-2h. Thereby, for example, when the liquid crystal display element is installed on the upper side and used as a backlight of the liquid crystal display device, the liquid crystal display element can be divided into eight areas to control the luminance of the backlight. This is because the luminance of the eight surface light-emitting plates 2a to 2h can be individually adjusted at high speed according to the properties of the image displayed on the liquid crystal display element. In addition, even if there is a scratch or dirt on one of the surface light emitting plates 2a to 2h or a failure of the light source 14 during the manufacturing process or during use after completion, the surface of the defective portion. It becomes possible to easily repair and repair by replacing the light emitting plate 2. Therefore, the manufacturing cost can be reduced, and the repair cost can be reduced.

<Example 6>
FIG. 6 shows a sixth embodiment of the lighting device according to the present invention, and is a partial sectional view in which the surface light emitting plate 2 is enlarged. The same parts or parts having the same function are denoted by the same reference numerals.

  A light shielding layer 24 is formed on the upper surface 23 of the light source unit 4a in a region where the light source unit 4a of the surface light emitting plate 2a and the light guide unit 3b of the surface light emitting plate 2b overlap. Other parts are the same as those of the fourth embodiment shown in FIG. By forming the light shielding layer 24 as in this embodiment, it is possible to prevent the light emitted from the light source part 4a from being directly irradiated upward and causing uneven brightness in the surface light emitting plate 2a or 2b. As the light shielding layer 24, a metal film or a black resin can be used. If the light shielding layer 24 is used as a light reflecting film such as aluminum to guide the light emitted from the light source 14a to the light guide 3a side, the light utilization efficiency can be further increased.

<Example 7>
FIG. 7 is a sectional view showing Example 7 of the liquid crystal display device 30 according to the present invention. The same parts or parts representing the same functions are denoted by the same reference numerals. In FIG. 7, the liquid crystal display device 30 includes the illumination device 1 that forms a backlight, and a liquid crystal display element 28 placed thereon. The illuminating device 1 includes a plurality of surface light emitting plates 2a to 2c, a reflection plate 19 disposed below the plurality of surface light emitting plates 2a to 2c, a frame 18 disposed below the plurality of surface light emitting plates 2a to 2c, and a diffusion plate 20 disposed on the plurality of surface light emitting plates 2a to 2c. And a frame 22 that integrally engages them. The frame 18 can radiate heat emitted from a light source (not shown) of the surface light emitting plates 2 a to 2 c through a heat radiating member (not shown) connected between the light source and the frame 18. A liquid crystal display element 28 composed of a polarizing plate 25, a liquid crystal panel 26, and a polarizing plate 27 is disposed on the lighting device 1.

  The liquid crystal display element 28 and the illumination device 1 are driven by a display control circuit (not shown). The surface light-emitting plates 2a to 2c constituting the illumination device 1 can be dimmed individually. Therefore, the liquid crystal control circuit can analyze the liquid crystal display data and dim the individual surface light emitting plates 2a to 2c to the luminance corresponding to the liquid crystal display data.

It is explanatory drawing of the illuminating device which concerns on Example 1 of this invention. It is sectional drawing and the top view of the illuminating device which concerns on Example 2 of this invention. It is sectional drawing of the illuminating device which concerns on Example 3 of this invention. It is the perspective view and sectional drawing of the illuminating device based on Example 4 of this invention. It is a disassembled perspective view of the illuminating device which concerns on Example 5 of this invention. It is sectional drawing of the illuminating device which concerns on Example 6 of this invention. It is sectional drawing of the liquid crystal display device which concerns on Example 7 of this invention. It is sectional drawing of a conventionally well-known liquid crystal display device. It is a disassembled perspective view of a conventionally well-known surface light-emitting device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Illuminating device 2a, 2b, 2c, 2d, 2e, 2f, 2h Surface light-emitting plate 3a, 3b Light guide part 4a, 4b Light source part 5a, 5b Upper surface 6a, 6b Lower surface 7a, 7b, 8a, 8b Inclined surface 9a, 9b End face 10a, 10b Stepped face 11 V groove 12a, 12b FPC
13a, 13b Heat dissipation member 14a, 14b Light source 15a, 15b Extension part 16 1st fluorescent substance layer 17 2nd fluorescent substance layer

Claims (13)

In the illuminating device in which a plurality of planar light emitting plates configured integrally with a light guide unit and a light source unit installed at an end of the light guide unit are arranged in a plane,
The light source part of the said surface light-emitting plate and the light guide part of another adjacent surface light-emitting board are arranged so that it may overlap in a plane.   The light guide part has a wedge-shaped cross section, the light source part of the surface light emitting plate is installed in the thick part of the wedge shape, and the light guide parts of the other adjacent surface light emitting plates are thin in the wedge shape. The lighting device according to claim 1, wherein the portion is arranged so as to overlap the light source portion of the surface light emitting plate.   The illumination device according to claim 2, wherein an angle between an upper surface and a lower surface forming the wedge shape is 1 ° to 10 °.   In a region where the surface light emitting plate and the other adjacent surface light emitting plate overlap in a planar manner, a step portion is formed on the upper surface of the surface light emitting plate, and an end of the other surface light emitting plate adjacent to the step portion. The lighting device according to any one of claims 1 to 3, wherein a portion is installed, and light is introduced from the other adjacent surface light emitting plate to the surface light emitting plate.   The lighting device according to claim 1, wherein a reflection surface is formed on a surface of the light source unit of the surface light emitting plate.   The lighting device according to claim 1, wherein a surface of the light guide unit is a light diffusion surface that diffuses light.   The lighting device according to claim 6, wherein the light diffusion surface has a structure in which a number of V grooves are formed on a surface of the light guide unit.   The angle formed between the surface of the light guide unit and the inclined surface of the V-groove is 0.25 ° to 3.0 °, and the pitch of the V-groove is 0.25 μm to 200 μm. 8. The lighting device according to 7.   The lighting device according to claim 1, wherein the light source unit includes a light emitting diode and a heat radiating member for radiating heat from the light emitting diode.   The lighting device according to claim 9, wherein the light emitting diode is a blue light emitting diode, and the light source unit includes a red phosphor and a green phosphor.   A reflector disposed under the surface light-emitting plate; and a frame disposed under the reflector. The heat radiating member is connected to the frame, and heat from the light-emitting diode is radiated to the frame. The illuminating device according to claim 9, wherein the lighting device has a configuration in which In a liquid crystal display device comprising an illumination device and a liquid crystal display element disposed on the illumination device,
In the lighting device, a plurality of planar light emitting plates each integrally configured of a light guide unit and a light source unit installed at an end of the light guide unit are arranged in a plane, and the light source of the surface light emitting plate A liquid crystal display device in which a portion and a light guide portion of another adjacent surface light emitting plate are arranged so as to overlap each other in a planar manner.   An image data output circuit for outputting image data to the liquid crystal display element; and an illumination drive circuit for driving the illumination device. The illumination drive circuit configures the illumination device by inputting the image data. The liquid crystal display device according to claim 12, wherein a light source unit of each of the plurality of surface light emitting plates is controlled according to the image data.

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