WO2012128193A1

WO2012128193A1 - Lighting device and display device

Info

Publication number: WO2012128193A1
Application number: PCT/JP2012/056815
Authority: WO
Inventors: 寺島　健太郎
Original assignee: シャープ株式会社
Priority date: 2011-03-23
Filing date: 2012-03-16
Publication date: 2012-09-27

Abstract

This lighting device (12) is provided with: a container member (15) which has a bottom plate (15a) and a side wall (15b) extending upwardly from the bottom plate (15a); a light guide plate (16), which has a pair of plate surface (16a, 16b) that are parallel to each other and an inclined end surface (16c) that is inclined to the plate surface (16a), and which is arranged within the container member (15) such that the plate surface (16b) faces to the bottom plate (15a); a light source unit (17) which comprises an LED (172) that emits light from a front end surface (172a) and an LED substrate (171) on which the LED (172) is mounted; and a supporting member (18) which is arranged within the container member (15) and supports the light source unit (17) such that the front end surface (172a) of the LED (172) faces to the inclined end surface (16c).

Description

Lighting device and display device

The present invention relates to a lighting device and a display device.

In recent years, liquid crystal panels have been widely used as display units for televisions, mobile phones, portable information terminals and the like. Since the liquid crystal panel cannot emit light by itself, in order to display an image, the light of a separately prepared illumination device (so-called backlight) is used. This illuminating device is arranged on the back side of the liquid crystal panel, and is configured to irradiate light spreading in a plane toward the back side of the liquid crystal panel.

As the illuminating device, one having a light guide plate and a light source unit arranged so as to face the end face of the light guide plate is known. This type of lighting device is generally known as a side light type (or edge light type), and as the light source unit, for example, a plurality of LEDs and LEDs on which these LEDs are mounted. What is provided with a board | substrate is known. The light guide plate and the light source unit are accommodated in a box-shaped chassis.

When light is emitted from each LED mounted on the LED substrate toward the end face of the light guide plate, the light enters the inside from the end face of the light guide plate and is laid under the light guide plate. The light advances through the light guide plate while being reflected by the reflecting sheet or the like. Then, the light is emitted as planar light from the surface of the light guide plate. The light emitted from the surface of the light guide plate passes through a transparent resin optical sheet disposed on the surface side of the light guide plate, and illuminates the liquid crystal panel from the back side.

Note that the end face of the light guide plate is generally formed perpendicular to the front or back surface of the light guide plate. Moreover, as shown in Patent Document 1, some are formed so as to be inclined with respect to the front surface or the back surface of the light guide plate.

JP 2008-262766 A

(Problems to be solved by the invention)
In order to increase the utilization efficiency of the light emitted from the LED, the size of the LED is preferably set so as to be within the end face of the light guide plate so as not to protrude from the end face of the light guide plate. Therefore, when the light guide plate is thin, the size of the LED used is generally small.

By the way, a small one (for example, one having a width of 1.5 mm or less) among general-purpose LEDs (LED packages) is an LED due to the fact that the volume of the resin containing the phosphor is small and the heat dissipation area is small. The efficiency of converting blue light into white light is low, and the light emission efficiency is poor. Therefore, when the thickness of the light guide plate is small and a small LED that fits within the end face of the light guide plate is used, it is difficult to ensure sufficient brightness of the lighting device.

An object of the present invention is to provide a technique capable of setting a large end face on which light is incident without increasing the thickness of the light guide plate.

(Means for solving problems)
The lighting device according to the present invention includes a receiving member having a bottom plate and a side wall rising from the bottom plate, a pair of plate surfaces parallel to each other, and an inclined end surface inclined with respect to the plate surface, and the plate surface A light source plate having a light guide plate arranged in the housing member so that one of the LED faces the bottom plate, an LED that emits light from a front end surface, and an LED substrate on which the LED is mounted; And a support member disposed in the housing member while supporting the light source unit so that a front end surface faces the inclined end surface. The illuminating device can set the width of the inclined end surface on which light is incident to be large without increasing the thickness of the light guide plate by inclining the inclined end surface of the light guide plate with respect to the plate surface of the light guide plate. .

In the lighting device, the support member may be made of a heat dissipation material and connected to the bottom plate and the side wall. The lighting device can release heat generated from the light source unit to the bottom plate and the side wall via a support member.

In the illumination device, the inclined end surface may be inclined with respect to the plate surface so as to look down on the bottom plate.

In the lighting device, the front end surface of the LED and the inclined end surface are arranged in parallel to each other, and the width h (mm) of the front end surface of the LED in a direction corresponding to the inclination direction of the inclined end surface, The relationship with the thickness t (mm) of the light guide plate may be 0.8 ≦ t / h ≦ 1.2.

In the illumination device, a thickness t (mm) of the light guide plate may be 0.5 ≦ t ≦ 3.

In the lighting device, an angle θ (°) formed by the thickness direction of the light guide plate and the inclination direction of the inclined end surface is 0 <θ <90−arc · sin (1 / n) (where n is a value of the light guide plate) (Refractive index).

In the illuminating device, of the pair of plate surfaces of the light guide plate, the plate surface on which the principal ray emitted from the front end surface of the LED first hits after passing through the inclined end surface is more than the portion on which the principal ray strikes. It is preferable to have a light leakage prevention part in the outer edge side part.

In the lighting device, it is preferable that the support member has a notch groove.

The display device according to the present invention includes a display panel that performs display using light from the illumination device.

In the display device, the display panel may be a liquid crystal panel using liquid crystal.

(The invention's effect)
According to the present invention, there is provided a technique capable of setting a large end face on which light is incident without increasing the thickness of the light guide plate.

FIG. 3 is a plan view of the liquid crystal display device according to the first embodiment. Cross section of liquid crystal display Enlarged sectional view of a liquid crystal display device Sectional drawing of the liquid crystal display device of Embodiment 2. Sectional drawing of the liquid crystal display device of Embodiment 3. Sectional drawing of the liquid crystal display device of Embodiment 4.

<Embodiment 1>
Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 3. In the present embodiment, the liquid crystal display device 10 will be described as an example. FIG. 1 is a plan view of the liquid crystal display device of Embodiment 1, FIG. 2 is a cross-sectional view of the liquid crystal display device, and FIG. 3 is an enlarged cross-sectional view of the liquid crystal display device. For convenience of explanation, the X axis, the Y axis, and the X axis are shown in each drawing.

As shown in FIG. 1, the liquid crystal display device 10 has a substantially rectangular appearance when viewed from the front side. FIG. 1 shows a rectangular liquid crystal panel 11 and a frame-shaped bezel 13 surrounding the outer edge portion of the liquid crystal panel 11. FIG. 2 shows a cross-sectional view of the liquid crystal display device 10 cut along the long side direction. As shown in FIG. 2, the liquid crystal display device 10 mainly includes a liquid crystal panel (an example of a display panel) 11 that displays an image, a backlight device (an example of an illumination device) 12, a bezel 13, and a frame 14. ing. The liquid crystal display device 10 of this embodiment is used as a display unit of various electronic devices such as a portable information terminal, a mobile phone, a notebook computer, a portable television receiver, and a portable game machine.

As described above, the liquid crystal panel 11 is rectangular in appearance, and mainly includes a pair of transparent glass substrates facing each other and a liquid crystal layer sealed between these substrates. Among these substrates, one glass substrate disposed on the back side (back side) is a thin film transistor (hereinafter, TFT) array substrate, and the other glass substrate disposed on the display surface side (front side) is A color filter (hereinafter referred to as CF) substrate. The liquid crystal panel 11 of FIG. 1 shows the display surface 11a side (front side). 2 and 3, the upper side is the display surface 11a side (front side) of the liquid crystal panel 11, and the lower side thereof is the back surface 11b side (back side) of the liquid crystal panel.

The TFT array substrate is mainly composed of a plurality of TFTs as switching elements and a plurality of transparent pixel electrodes connected to the drain electrodes of each TFT in a matrix (matrix) on a transparent glass plate. It consists of what is provided. Individual TFTs and pixel electrodes are provided for each pixel, and are partitioned by a plurality of gate wirings and a plurality of source wirings provided on the glass plate so as to cross each other. . Note that the gate electrode in each TFT is connected to the gate wiring, and the source wiring is connected to the source wiring. In addition, the TFT array substrate is formed with an alignment film for regulating the alignment of liquid crystal molecules contained in the liquid crystal layer.

The CF substrate is mainly formed on a transparent glass plate so that the CF composed of each color such as red (R), green (G), and blue (B) corresponds to each pixel of the TFT array substrate. It consists of what was provided in matrix form. Each CF is partitioned by a light-shielding black matrix (hereinafter referred to as BM) provided in a lattice pattern on the glass plate. A transparent counter electrode facing the pixel electrode of the TFT array substrate on the CF and the BM. In addition, an alignment film for regulating the alignment of the liquid crystal molecules is provided.

Image data and various control signals necessary for displaying an image are supplied to the above-described source wiring, gate wiring, counter electrode, and the like from a drive circuit board (not shown) provided in the liquid crystal display device 10. It is configured. The liquid crystal panel 11 is driven by a so-called active matrix method. The liquid crystal panel 11 is provided with polarizing plates on the display surface side and the back surface side so as to sandwich the pair of glass substrates.

The illuminating device 12 is a so-called edge light type (side light type) backlight. As shown in FIGS. 2 and 3, the illuminating device 12 mainly includes a chassis (an example of a housing member) 15, a light guide plate 16, and a light source. A unit 17, a support member (heat dissipation member) 18, an optical sheet 19, and a reflection sheet 20 are provided.

The chassis 15 is a shallow box with an upper opening, and is obtained by pressing a plate material made of a metal material such as an aluminum-based material. In other embodiments, the chassis 15 may be manufactured using a plastic material. In addition, as a material utilized for the chassis 15, what has moderate rigidity and is excellent in heat dissipation (for example, the said metal material) is preferable. The chassis 15 includes a bottom plate 15a having a rectangular appearance when viewed from the front side, and a side wall 15b formed so as to stand up at the peripheral edge of the bottom plate 15b.

It should be noted that the surface of the bottom plate 15a is set so that the peripheral portion adjacent to the side wall 15b is lower than the central portion thereof. That is, a recess 15c is formed in a portion adjacent to the side wall 15b, and the surface of the bottom plate 15a in that portion is set to be one step lower than the surface of the central portion. The surface of the bottom plate 15a in the central portion is processed to be substantially flat. Further, the portion corresponding to the bottom of the recess 15c is also processed to be substantially flat. And the thickness of the bottom plate 15a in the said hollow 15c is set smaller (thinner) than the thickness of the bottom plate 15a in the said center part. As will be described later, the recess 15c serves as a place (space) for accommodating the support member 18 that supports the light source unit 17.

The reflection sheet 20 has a rectangular shape whose appearance is slightly smaller than the bottom plate 15a, and is made of a white foamed plastic sheet (for example, a foamed polyethylene terephthalate sheet). The reflection sheet 20 is accommodated in the box-shaped chassis 15 so as to cover the surface of the bottom plate 15a. The reflection sheet 20 covers the entire surface of the bottom plate 15a in the central portion that is set one step higher than the depression 15c. The outer edge portion of the reflection sheet 20 is set so that it does not reach the side wall 15b but slightly reaches the recess 15c.

The light guide plate 16 is made of a transparent plate-like member having a predetermined thickness t (mm), and is manufactured using a highly transparent material such as acrylic resin. The appearance of the light guide plate 16 when viewed from the plate surface (front surface 16a or back surface 16b) side is generally rectangular. That is, the front plate surface (front surface 16a) of the light guide plate 16 and the back plate surface (back surface 16b) are both rectangular. The front surface 16a and the back surface 16b of the light guide plate 16 facing each other are both flat and parallel to each other. In the present specification, the pair of plate surfaces (the front surface 16a and the back surface 16b) of the light guide plate 16 is not limited to the case where both plate surfaces are completely parallel to each other. The case where the surfaces are generally parallel as a whole is also included. The thickness t (mm) of the light guide plate 16 is a distance between the front surface 16a and the back surface 16b. A desirable range for the thickness t (mm) of the light guide plate is 0.5 ≦ t ≦ 3. If the thickness t (mm) of the light guide plate 16 is less than 0.5, the thickness is too thin, so that a margin when the end surface 16c of the light guide plate 16 is inclined cannot be expected. This margin takes into account variations in the LEDs 172 mounted on the LED substrate 171. Further, when the thickness t (mm) of the light guide plate 16 exceeds 3, the thickness becomes large (thick), so that it is not necessary to incline the end surface 16c of the light guide plate 16 to earn a margin.

The pair of end surfaces 16c and 16c on the short side of the light guide plate 16 are both inclined with respect to the front surface 16a or the back surface 16b. In the present specification, the inclined end surface 16c may be particularly referred to as an inclined end surface 16c. The surface of the inclined end surface 16c is flat, and as shown in FIGS. 2 and 3, is inclined so as to climb from the back surface 16b side toward the front surface 16a side. In other words, the inclined end surface 16c is inclined so as to face upward (open) of the chassis 15. The inclined end surface 16c is sandwiched between the short side on the front surface 16a side and the short side on the back surface 16b side. In the present embodiment, the distance (shortest distance) between them is the width of the inclined end face 16c.

An angle θ (°) (see FIG. 3) formed by the width direction of the inclined end surface 16c and the thickness direction (Z-axis direction) of the light guide plate 16 (that is, the normal direction of the front surface 16a or the back surface 16b) is an LED 172 described later. Is set to be equal to or smaller than the critical angle of the chief ray L emitted from. A specific range of the angle θ (°) is 0 <θ <90−arc · sin (1 / n). Here, n is the refractive index of the light guide plate. Although not shown, the pair of end faces on the long side of the light guide plate 16 are both perpendicular to the front surface 16a or the back surface 16b.

A light scattering portion (not shown) is provided on the back surface 16 b of the light guide plate 16. The light scattering portion is configured by a white dot pattern and has a function of scattering and reflecting light. For example, the light scattering portion is formed by printing a paste containing a white pigment such as a metal oxide on the back surface 16b of the light guide plate 16 using a silk screen printer.

The light guide plate 16 is accommodated in the chassis 15 such that the back surface 16b faces the bottom plate 15a. The light guide plate 16 is placed on the bottom plate 15 a via the reflection sheet 20. The light guide plate 16 is disposed on the bottom plate 15a so that the inclined end surface 16c is adjacent to the recess 16c. There is a gap between the inclined end surface 16c and the side wall 15b of the chassis 15, and a support member 18 that supports the light source unit 17 is disposed in the gap as will be described later.

The light source unit 17 mainly includes an LED (Light Emitting Diode) 172 as a light source and an LED substrate 171 on which the LED 172 is mounted. The LED 172 is formed by sealing a plurality of LED chips in a housing with a resin material or the like (so-called LED package), and is configured to emit white light. The LED 172 includes, for example, three types of LED chips having different main emission wavelengths. Specifically, each LED chip emits red (R), green (G), and blue (B) in a single color. Is configured to do. The LED 172 is not limited to such a configuration, and may have another configuration. Other configurations of the LED 172 include, for example, a built-in LED chip that emits blue (B) in a single color, a phosphor having an emission peak in the red (R) region, and an emission peak in the green (G) region. The LED chip may be covered with a resin mixed with a phosphor (for example, a silicon-based resin). Further, as another configuration, a resin (for example, a silicon-based resin) in which an LED chip that emits blue (B) in a single color is incorporated and a phosphor that emits yellow light such as YAG (yttrium, aluminum, garnet) phosphor is mixed. ), The LED chip may be covered.

The LED 172 of the present embodiment is a rectangular parallelepiped whose appearance is flat, and light is emitted from a rectangular tip surface 172a. As will be described later, the LED 172 is disposed in the chassis 15 so as to face the inclined end surface 16 c of the light guide plate 16. Of the front end surface 172a, the width (length) h (mm) in the direction corresponding to the width direction of the inclined end surface 16c does not protrude from the inclined end surface 16c in order to increase the light use efficiency. It is preferable that the width is set to be equal to or less than the width of the. The relationship between the width h (mm) of the tip surface 172a of the LED 172 and the thickness t (mm) of the light guide plate 16 is preferably 0.8 ≦ t / h ≦ 1.2. If the width h (mm) of the front end surface 172a satisfies the above relationship, for example, even if the width h of the front end surface 172a is larger than the thickness t (mm) of the light guide plate 16, the inclined end surface By using 16c, light leakage of the LED 172 can be suppressed. Therefore, a general-purpose LED having a relatively high width h and a high brightness can be used.

The LED substrate 171 includes a long (band-shaped) base material made of a metal material such as an aluminum material, an insulating layer made of a synthetic resin formed on the base material, and copper formed on the insulating layer. A wiring pattern made of a metal film such as a foil and a white insulating film formed on the insulating layer so as to cover the wiring pattern are provided. For convenience of explanation, the base material, the insulating layer, the metal film, and the insulating film are collectively shown as one LED substrate 171 in FIGS. On the substrate surface 171a of the LED substrate 171, a plurality of LEDs 172 are mounted in a line. The LEDs 172 are connected to each other in series by the wiring pattern.

The lighting device 12 includes an LED driver (not shown). By the LED driver, current is supplied to each LED 172 on the LED substrate 171, and each LED 172 is driven by PWM (Pulse Width Modulation) control. The

The support member 18 is accommodated in the chassis 15 while supporting the light source unit 17. The support member 18 of the present embodiment is made of a material excellent in heat dissipation (hereinafter referred to as a heat dissipation material). Examples of the heat dissipation material include metal materials such as aluminum-based materials. The external shape of the support member 18 is a prismatic shape that extends straight so that the long light source unit 17 can be supported. The cross-sectional shape of the support member 18 (the cross-sectional shape of the support member 18 cut so as to be orthogonal to the longitudinal direction) is a combination of a rectangle and a triangle, as shown in FIGS. Yes. The support member 18 is disposed in the recess 15 c of the bottom plate 15 a in the chassis 15. The support member 18 is attached to the chassis 15 by using known fixing means such as screwing and adhesive.

Here, for convenience of explanation, the support member 18 will be described by dividing it into a portion 18b having a rectangular cross section and a portion 18c having a triangular cross section. Of the support member 18, a portion 18 b having a rectangular cross section is in close contact with the side wall 15 b and the bottom plate 15 a of the chassis 15. Specifically, the long side portion of the portion 18b having a rectangular cross section is in close contact with the inner surface of the side wall 15b. The portion on the short side is in close contact with the surface of the bottom plate 15a corresponding to the bottom of the recess 15c. That is, the support member 18 is connected to the side wall 15 b and the bottom plate 15 a of the chassis 15, and heat generated from the light source unit 17 can be easily released to the chassis 15 via the support member 18. As shown in FIGS. 2 and 3, the portion 18b having a rectangular cross section of the support member 18 has a flat plate shape extending upward along the side wall 15b.

The portion 18c having a triangular cross section in the support member 18 is closer to the light guide plate 16 in the chassis 15 than the portion 18b having a rectangular cross section. The section 18c having a triangular cross section has an attachment surface 18a inclined so as to face the bottom plate 15a, and the LED substrate 171 of the light source unit 17 is attached to the attachment surface 18a. The LED substrate 171 is fixed on the mounting surface 18a with respect to the support member 18 by using a known fixing means such as an adhesive or screwing.

The support member 18 supports the light source unit 17 so that the front end surface 172a of the LED 172 and the inclined end surface 16c of the light guide plate 16 are arranged in parallel to each other. A slight gap is provided between the front end surface 172 a of the LED 172 and the inclined end surface 16 c of the light guide plate 16 in consideration of thermal expansion of the light guide plate 16. In the present embodiment, a plurality of light source units 17 are provided in the chassis 15 (in the case of the present embodiment) so as to face the pair of end surfaces (inclined end surfaces) 16c, 16c on the short side of the light guide plate 16, respectively. 2) (see FIG. 2).

The optical sheet 19 is composed of a laminate of a diffusion sheet, a lens sheet, and a reflective polarizing sheet. The external shape of the optical sheet 19 is rectangular when viewed from the front side, and is placed on the surface 16 a so as to cover the surface 16 a of the light guide plate 16. The diffusion sheet is made of, for example, a laminate of a light-transmitting substrate made of synthetic resin and a diffusion layer in which light scattering particles are dispersed and mixed. This diffusion sheet has a function of diffusing light emitted from the surface 16 a of the light guide plate 16. The lens sheet has a function of adjusting the traveling direction of light that has passed through the diffusion sheet, for example, from a surface in which a convex lens is formed on the surface of a translucent base material made of synthetic resin. The reflective polarizing sheet has a function of reflecting linearly polarized light having a vibration plane orthogonal to the transmission polarization axis. As shown in FIGS. 2 and 3, the liquid crystal panel 11 is disposed above the optical sheet 19.

The frame 14 has a frame shape and is made of synthetic resin. The frame 14 is black and has a light shielding property. As shown in FIGS. 2 and 3, the frame 14 is placed on the chassis 15 containing the light guide plate 16, the optical sheet 19, and the like from the opened upper side. That is, the frame 14 is put on the chassis 15 so as to cover the tip portion of the side wall 15b. The inner peripheral edge of the frame 14 extends in a bowl shape from the side wall 15b side of the chassis 14, and the extended portion causes the peripheral edge on the surface 16a of the light guide plate 16, the light source unit 17, the support member 18, and the like. Is covered. The frame 14 is fixed to the side wall 15b of the chassis 15 by screws or the like. Further, the peripheral edge of the liquid crystal panel 11 is placed on the inner peripheral edge of the frame 14. Thus, the frame 14 supports the liquid crystal panel 11 from the back side.

The liquid crystal panel 11 is fixed to the illuminating device 12 with its outer peripheral edge sandwiched between a frame 14 and a frame-like bezel 13 covered from the upper side of the frame 14. The bezel 13 is made of metal, and is fixed to the side wall 15b of the chassis 15 together with the frame 14 by screwing or the like.

When the liquid crystal display device 10 displays an image on the surface 11a of the liquid crystal panel 11, each LED 172 of the light source unit 17 included in the illumination device 12 emits light. The light is emitted from the front end surface 172a of the LED 172. When each LED 172 emits light, light enters the inclined end surface 16c of the light guide plate 16 into the inside thereof. The incident light is reflected by the reflection sheet 20 laid on the back surface 16 b side of the light guide plate 16, a light scattering portion (not shown) formed on the back surface 16 b of the light guide plate 16, etc. The light exits from the surface 16a while proceeding inside. The emitted light passes through the optical sheet 19 and spreads into a planar shape, and illuminates the liquid crystal panel 11 from the back surface 11b side. The liquid crystal panel 11 uses the light from the illumination device 12 to display an image on the surface thereof.

Note that FIG. 3 shows the principal ray L emitted from the LED 172. This chief ray L is emitted straight from the substantially central portion of the tip surface 172a of the light emitted from the LED 172 along its normal direction. In FIG. It is shown schematically using. The principal ray L enters the light guide plate 16 from the inclined end surface 16 c and is reflected by the back surface 16 b of the light guide plate 16. That is, the principal ray L first strikes the back surface 16 b of the pair of plate surfaces of the light guide plate 16.

The end face (inclined end face 16c) of the light guide plate 16 of the illumination device 12 of the present embodiment is inclined. The light source unit 17 is supported by the support member 18 so that the tip end surface 172a of the LED 172 faces the inclined end surface (inclined end surface 16c). In this way, the thickness t (mm) of the light guide plate 16 is increased by inclining the end surface (inclined end surface 16c) of the light guide plate 16 with respect to the plate surface (front surface 16a or back surface 16b) of the light guide plate 16. However, the width of the end face (inclined end face 16c) on which light is incident can be set large. Therefore, the width of the LED 172 opposed to the inclined end face 16 can be set large, and a high-luminance general-purpose LED can be used as the LED 172. In some cases, it is also possible to use an LED 172 having a larger width h (mm) of the front end surface 172a than the thickness t (mm) of the light guide plate 16.

Further, the lighting device 12 of the present embodiment is configured such that the light source unit 17 is inclined with respect to the plate surface (the front surface 16a or the back surface 16b) of the light guide plate 16 or the bottom plate 15a using the support member 18. It is fixed inside. The light source unit 17 is fixed to the support member 18 in a state where the LED substrate 171 is mounted on a mounting surface 18c inclined toward the bottom plate 15a side. Thus, in the lighting device 12 of the present embodiment, the light source unit 17 is fixed in a stable state in the chassis 15 using the support member 18.

Further, as described above, the support member 18 that supports the light source unit 17 is made of a heat dissipation material, and is connected to the bottom plate 15a and the side wall 15b of the chassis 15. Therefore, the heat generated from the light source unit 17 when the LED 172 is turned on can first move to the support member 18 and further to the chassis 15. The chassis 15 is cooled by outside air. Therefore, the lighting device 12 of the present embodiment can efficiently release the heat generated from the light source unit 17 to the chassis 15 via the support member 18.

<Embodiment 2>
Next, Embodiment 2 of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view of the liquid crystal display device 10A according to the second embodiment. The portion of the liquid crystal display device 10A shown in FIG. 4 corresponds to the portion of the liquid crystal display device 10 of the first embodiment shown in FIG. The basic structure of the liquid crystal display device 10A of the present embodiment is the same as that of the first embodiment. However, the liquid crystal display device 10A of the present embodiment is different from that of the first embodiment in the structure of the support member 18A. Here, the support member 18A will be mainly described.

The illumination device 12A included in the liquid crystal display device 10A supports the light source unit 17 by a support member 18A. The appearance of the support member 18A is substantially the same as that of the first embodiment, except that a notch groove 18d is provided in a portion in contact with the side wall 15b. A plurality of the cutout grooves 18d are provided in the longitudinal direction (X-axis direction) of the support member 18A. The notch groove 18d is provided in order to increase the surface area of the support member 18A made of a heat dissipation material compared to that of the first embodiment. Thus, the heat dissipation efficiency of the support member 18A may be improved by forming the notch groove 18d in the support member 18A.

<Embodiment 3>
Next, Embodiment 3 of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view of the liquid crystal display device 10B of the third embodiment. The portion of the liquid crystal display device 10B shown in FIG. 5 corresponds to the portion of the liquid crystal display device of the first embodiment shown in FIG. The basic structure of the liquid crystal display device 10B of this embodiment is the same as that of the first embodiment. However, the liquid crystal display device 10 </ b> B of the present embodiment is different from that of the first embodiment in that the light leakage prevention unit 21 is provided. Here, the light leakage prevention unit 21 will be mainly described.

In the illumination device 12B provided in the liquid crystal display device 10B, a light leakage prevention portion 21 having a white surface is provided between the outer edge portion of the light guide plate 16 on the back surface 16b side and the reflection sheet 20. The light omission prevention unit 21 is made of, for example, a double-sided tape whose surface is white. As described above, when the light omission prevention unit 21 is provided, the light emitted from the LED 172 is reliably reflected by the light omission prevention unit 21 and efficiently guided into the light guide plate 16. In addition, it is preferable that this light omission prevention part 21 is provided in the part of an outer edge side rather than the part where the chief ray L of LED172 strikes the back surface 16b first. If the light omission prevention portion 21 is provided in this portion, the light hitting that portion is easily guided into the light guide plate 16. As a result, the illuminating device 12B of this embodiment can further improve the utilization efficiency of the light emitted from the LED.

<Embodiment 4>
Next, Embodiment 4 of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view of the liquid crystal display device 10C according to the fourth embodiment. The portion of the liquid crystal display device 10C shown in FIG. 6 corresponds to the portion of the liquid crystal display device of Embodiment 1 shown in FIG. The basic structure of the liquid crystal display device 10C of this embodiment is the same as that of the first embodiment. However, the liquid crystal display device 10C of the present embodiment is different from that of the first embodiment in the structure of the light guide plate 16C, the support member 18C, and the like. Here, the light guide plate 16C, the support member 18C, and the like will be mainly described.

The illuminating device 12C provided in the liquid crystal display device 10C is inclined such that the inclined end surface 16Cc of the light guide plate 16C facing the light source unit 17 is directed toward the bottom plate 15a (looking down on the bottom plate 15a). In other words, the inclined end surface 16Cc of the present embodiment is reversely inclined compared to the inclined end surface 16c of the first embodiment. The angle θ (°) formed by the width direction of the inclined end face 16Cc and the thickness direction (Z-axis direction) of the light guide plate 16C (that is, the normal direction of the front surface 16Ca or the back surface 16Cb) is as shown in FIG. And on the back surface 16Cb side of the light guide plate 16C.

The shape of the support member 18Cc that supports the light source unit 17 is also different from that of the first embodiment. The support member 18 </ b> Cc of this embodiment has a substantially prismatic shape that extends straight so that the long light source unit 17 can be supported, as in the first embodiment. However, as shown in FIG. 6, the cross-sectional shape is a combination of a rectangle and a triangle, which are different from those of the first embodiment. The section 18Cb having a rectangular cross section is in close contact with the side wall 15b and the bottom plate 15a of the chassis 15 as in the first embodiment, but its thickness (thickness in the Y-axis direction) is thinner than that in the first embodiment. It has become. Further, the section 18Cc having a triangular cross section is located on the light guide plate 16C side in the chassis 15 as compared with the section 18Cb having a rectangular cross section, as in the first embodiment, but the mounting surface 18Ca provided in the section 18Cc is located on the upper side. Inclined to head towards. Further, the lower portion of the triangular section 18Cc is in close contact with the bottom plate 15a of the chassis 15. Note that the support member 18C that supports the light source unit 17 is disposed in a recess 15c formed in the bottom plate 15a, as in the first embodiment.

The support member 18C has a larger contact area with the bottom plate 15a than that of the first embodiment. And the back surface side of LED board 171 is orient | assigned to the baseplate 15a side. The heat generated from the light source unit 17 is transmitted to the support member 18C exclusively from the back side of the LED substrate 171. Therefore, when the distance between the back surface of the LED substrate 171 and the bottom plate 15a is short, the heat generated from the light source unit 17 can easily escape to the bottom plate 15a of the chassis 15 via the support member 18C. The bottom plate 15a of the chassis 15 is larger than the side wall 15b and has a large area in contact with the outside air. For this reason, when the heat generated from the light source unit 17 is efficiently led mainly to the bottom plate 15a of the chassis 15, the temperature rise of the light source unit 17 (temperature rise in the lighting device 12C) can be easily suppressed. Therefore, the liquid crystal display device 10 </ b> C of the present embodiment can easily release the heat generated from the light source unit 17 to the outside, and is excellent in heat dissipation efficiency.

Note that the liquid crystal display device 10C of the present embodiment is also provided with the light leakage prevention unit 22 on the light guide plate 16C, as in the third embodiment. The light leakage prevention unit 22 is provided between the light guide plate 16 </ b> C and the optical sheet 19, unlike the third embodiment. This light omission prevention part 22 consists of a double-sided tape whose front surface (and back surface) is white. When such a light omission prevention portion 21 is provided, the light emitted from the LED 172 is reliably reflected by the light omission prevention portion 22 and is externally transmitted from the outer edge portion on the surface 16Ca side of the light guide plate 16C. In addition, it is possible to prevent light from being lost. Then, the light hitting that portion is easily guided into the light guide plate 16C. As a result, the illuminating device 12C of this embodiment can further improve the utilization efficiency of the light emitted from the LED 172. In addition, it is preferable that this light omission prevention part 22 is provided in the part of an outer edge side rather than the location where the chief ray L of LED172 strikes the surface 16Ca first.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

(1) In the above embodiment, the cross-sectional shape of the support member is a combination of a rectangle and a triangle. However, in other embodiments, the optical unit is not limited to this, and the optical unit is inclined by the light guide plate. Other shapes may be used as long as they can be supported so as to face the end surface. For example, the case where the cross-sectional shape of the support member of Embodiment 4 consists only of a triangle may be sufficient.

(2) In the above embodiment, the recess is provided in the bottom plate of the chassis. However, in other embodiments, as long as the support member can be accommodated so that the optical unit can be opposed to the inclined end surface of the light guide plate. The recess may not be formed in the bottom plate of the chassis.

(3) In the above embodiment, the light source unit is disposed along the pair of end surfaces on the short side of the light guide plate. However, in other embodiments, the light source unit is disposed along the pair of end surfaces on the long side. It may be arranged. In other embodiments, the light source unit may be disposed so as to face any one end face, or the light source unit may be placed so as to face all end faces.

(4) In the above embodiment, the thickness of the light guide plate is uniform. However, in other embodiments, the thickness of the light guide plate may not be uniform as long as the object of the present invention can be achieved.

DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display device (display device), 11 ... Liquid crystal panel (display panel), 12 ... Illuminating device, 13 ... Bezel, 14 ... Frame, 15 ... Chassis (housing member), 15a ... Bottom plate, 15b ... Side wall, 15c ... Indentation, 16 ... light guide plate, 16a ... surface (plate surface), 16b ... back surface (plate surface), 16c ... tilted end surface, 17 ... light source unit, 171 ... LED substrate, 171a ... substrate surface, 172 ... LED, 172a ... tip Surface (light-emitting surface), 18 ... support member, 18a ... mounting surface, t ... thickness of light guide plate, h ... width of tip surface of LED

Claims

A housing member having a bottom plate and a side wall rising from the bottom plate;
A light guide plate having a pair of plate surfaces parallel to each other and an inclined end surface inclined with respect to the plate surface, and being disposed in the housing member so that one of the plate surfaces faces the bottom plate;
A light source unit having an LED that emits light from the front end surface, and an LED substrate on which the LED is mounted;
An illumination device comprising: a support member that supports the light source unit so that a front end surface of the LED faces the inclined end surface, and is disposed in the housing member.
The lighting device according to claim 1, wherein the support member is made of a heat dissipation material and is connected to the bottom plate and the side wall.
The lighting device according to claim 1 or 2, wherein the inclined end surface is inclined with respect to the plate surface so as to look down on the bottom plate.
The front end surface of the LED and the inclined end surface are arranged in parallel to each other, the width h (mm) of the front end surface of the LED in the direction corresponding to the inclination direction of the inclined end surface, and the thickness t of the light guide plate The lighting device according to claim 1, wherein a relationship with (mm) is 0.8 ≦ t / h ≦ 1.2.
The lighting device according to claim 1, wherein a thickness t (mm) of the light guide plate is 0.5 ≦ t ≦ 3.
An angle θ (°) formed by the thickness direction of the light guide plate and the inclination direction of the inclined end surface is 0 <θ <90−arc · sin (1 / n) (where n is the refractive index of the light guide plate). The lighting device according to any one of claims 1 to 5.
Of the pair of plate surfaces of the light guide plate, the plate surface on which the chief ray emitted from the front end surface of the LED first hits after passing through the inclined end surface is located on the outer edge side of the portion on which the chief ray strikes. The lighting device according to claim 1, further comprising a light omission prevention unit.
The lighting device according to any one of claims 1 to 7, wherein the support member has a notch groove.
A display device comprising: the illumination device according to any one of claims 1 to 8; and a display panel that performs display using light from the illumination device.
The display device according to claim 9, wherein the display panel is a liquid crystal panel in which liquid crystal is sealed between a pair of substrates.