JP2012022861A - Light source device, and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote heat radiation of the amount of heat generated accompanying light emission of a light source.SOLUTION: The light source device is provided with a light guide plate which has a thickness between a pair of main surfaces and emits light entered from one end face from a prescribed region of one of the main surfaces of the pair of the main surfaces, a light source which emits light toward the one end face of the light guide plate, and a light source board on one surface of which the light source is connected. The light source device is further provided with a spacer which is in contact with a face on the opposite side to the side where the light source is connected on the light source board. The spacer includes a light-shielding substrate having a light-shielding performance and a heat conductive substrate which is laminated on the light-shielding substrate and has a higher thermal conductivity than the light-shielding substrate.

Description

  The present invention relates to a light source device and a display device.

  A light source device mounted on a display device such as a liquid crystal display device is provided with an LED as a light source and a light guide plate that irradiates the liquid crystal panel with light from the LED (see, for example, Patent Document 1).

JP 2009-301912 A

By the way, in recent years, even in a small liquid crystal display device, the display quality has been remarkably upgraded, and high definition and high contrast are indispensable technical requirements. In order to achieve high contrast, measures are taken to increase the number of LEDs mounted or to increase the LED drive current. However, the rise in the temperature of the LED mounting portion has been a problem due to the deterioration of the space factor in the vicinity of the element due to the increase in the number of mounted LEDs and the increase in the amount of self-heating of the LED due to the increase in drive current.
For this reason, the subject of this invention is promoting the heat dissipation of the calorie | heat amount which arises from light emission of a light source.

In order to solve the above problems, according to one aspect of the present invention,
A light guide plate having a thickness between the pair of main surfaces and emitting light incident from one end surface from a predetermined region of one of the pair of main surfaces;
A light source that emits light toward the one end surface of the light guide plate;
In the light source device comprising a light source substrate connected on one surface of the light source,
A spacer in contact with a surface of the light source substrate opposite to the side to which the light source is connected;
The spacer includes a light-shielding substrate having a light-shielding property and a heat conductive substrate stacked on the light-shielding substrate and having a higher thermal conductivity than the light-shielding substrate.

According to another aspect of the invention,
A light guide plate having a thickness between the pair of main surfaces and emitting light incident from one end surface from a predetermined region of one of the pair of main surfaces;
A light source that emits light toward the one end surface of the light guide plate;
In the light source device comprising a light source substrate connected on one surface of the light source,
A spacer for providing a predetermined interval between the display panel disposed on the opposite side of the light source substrate to the side to which the light source is connected and the light source substrate;
The spacer includes a light-shielding substrate having a light-shielding property and a heat conductive substrate stacked on the light-shielding substrate and having a higher thermal conductivity than the light-shielding substrate.

In the light source device, preferably, the spacer is arranged so that the thermally conductive substrate is interposed between the light shielding substrate and the light source substrate.
Preferably, in the light source device, a surface of the thermally conductive substrate opposite to the side on which the light source substrate is provided with respect to the thermally conductive substrate is on the opposite side of the thermally conductive substrate. A contact region that contacts the predetermined member and a separation region that is separated from the predetermined member are provided in a region facing the predetermined member.
Preferably, in the light source device, the thermally conductive substrate includes a groove provided on the opposite surface of the thermally conductive substrate, and a region where the groove is provided is the separation region.
Preferably, in the light source device, the separation region of the thermally conductive substrate is formed in a strip shape along the one end surface of the light guide plate.
Preferably, in the light source device, the separation region of the thermally conductive substrate is formed such that an end portion is disposed on a side of the thermally conductive substrate that intersects the one end surface of the light guide plate. Yes.
Preferably, in the light source device, the separation region of the thermally conductive substrate is formed such that the peripheral portion of the thermally conductive substrate has a higher rate per unit area than the central portion of the thermally conductive substrate. Has been.
Preferably, in the light source device, a region facing the light source is the separation region on the opposite surface of the thermally conductive substrate.
In the light source device, preferably, the thermally conductive substrate is in direct contact with the light source substrate.
Preferably, in the light source device, the spacer is provided with a first bonding member that is interposed between the thermally conductive substrate and the light source substrate and contacts the light source substrate.
Preferably, in the light source device, the spacer is in contact with the heat-shielding substrate so that the spacer contacts a second predetermined member provided on a side opposite to the side on which the light source substrate is provided. It has the 2nd joining member provided in the opposite side to the side in which the conductive substrate was provided.

According to another aspect of the invention,
The light source device;
A display panel irradiated with light emitted from the light source device,
A display device is provided, wherein the spacer is provided so as to be in contact with the display panel.

  Preferably, in the display device, the entire surface of the spacer opposite to the side on which the light source substrate is provided is in contact with the display panel.

  According to the present invention, it is possible to promote the heat dissipation of the amount of heat generated due to the light emission of the light source.

It is the disassembled perspective view which showed typically the whole structure of the display apparatus concerning this embodiment. It is arrow sectional drawing of the surface along the II-II line in FIG. It is arrow sectional drawing of the surface along the II-II line | wire in FIG. 1 of the spacer and LED unit with which the display apparatus of FIG. 1 is equipped. FIG. 4 is a cross-sectional view similar to FIG. 3 showing a modification of the spacer of FIG. 3. It is arrow sectional drawing of the surface along the VV line | wire of FIG. FIG. 6 is a cross-sectional view similar to FIG. 5 showing a modification of the spacer of FIG. 5. FIG. 6 is a cross-sectional view similar to FIG. 5 showing a modification of the spacer of FIG. 5. FIG. 6 is a cross-sectional view similar to FIG. 5 showing a modification of the spacer of FIG. 5. FIG. 6 is a cross-sectional view similar to FIG. 5 showing a modification of the spacer of FIG. 3.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

  FIG. 1 is an exploded perspective view schematically showing the overall configuration of a display device 100 according to the present embodiment. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is an enlarged view in which a part of the light source device 1 included in the display device 100 is enlarged. As shown in FIGS. 1 to 3, the display device 100 includes a light source device 1, a display panel 2, a case 3, and the like.

  The case 3 has an upper case 31 and a lower case 33. A rectangular display opening 31 b is formed in the top plate 31 a of the upper case 31. The lower case 33 houses the light source device 1 and the display panel 2, and the upper case 31 is engaged so as to cover them.

  The display panel 2 is a liquid crystal display panel, and includes a pair of transparent substrates 6 and 7 arranged to face each other with a predetermined gap as shown in FIG. Liquid crystal (not shown) is sealed in the gap between the transparent substrates 6 and 7. First and second transparent electrodes (not shown) are provided on the inner surfaces of the pair of transparent substrates 6 and 7 facing each other. The first and second transparent electrodes form a plurality of pixels in a matrix form that control the transmission of light by changing the alignment state of the liquid crystal molecules in the liquid crystal layer by applying a voltage. An optical sheet 23 including a polarizing plate is attached to the outer surface of the transparent substrate 7 on the front side. Here, the optical sheet 23 may include a polarizing plate and a retardation plate, or may include a reflective polarizing plate and a 1 / 4λ plate, and can be appropriately changed according to the application. On the other hand, a polarizing plate 24 is attached to the outer surface of the rear transparent substrate 6. In addition, the rear transparent substrate 6 is formed with an overhang 61 that projects from the front transparent substrate 7. A driver element 25 for applying a driving voltage between the transparent electrodes is mounted on the overhanging portion 61. In addition, a flexible wiring substrate 26 for supplying a control signal from an external circuit to the driver element 25 is connected to the overhang portion 61.

Next, the light source device 1 will be described.
The light source device 1 emits surface light toward the display panel 2 and is disposed on the rear side of the display panel 2. As shown in FIGS. 1 and 2, the light source device 1 includes a reflection sheet 11, a light guide plate 5, an LED (Light Emitting Diode) unit 15, a spacer 9, a frame 80, a light scattering sheet 41, One prism sheet 42 and a second prism sheet 43 are provided.

  The reflection sheet 11 is disposed to face the rear surface of the light guide plate 5 and reflects light leaking from the rear surface of the light guide plate 5 toward the inside of the light guide plate 5.

The light guide plate 5 has translucency and non-light scattering properties, and is formed in a rectangular shape in front view by, for example, polycarbonate or acrylic. Of the pair of main surfaces of the light guide plate 5, the rear main surface facing the reflection sheet 11 is a first main surface 51, and the front main surface facing the display panel 2 is a second main surface 52. The light guide plate 5 has a thickness between the pair of main surfaces 51 and 52. One end surface 53 of the light guide plate 5 is an incident surface on which light from the LED unit 15 is incident. Light incident from the incident surface is emitted from the second main surface 52 of the pair of main surfaces 51 and 52. It is supposed to be. The second main surface 52 is an emission surface.
On the front side of the light guide plate 5, a light scattering sheet 41, a first prism sheet 42, and a second prism sheet 43 are disposed so as to overlap each other. Although not shown, a light shielding sheet is provided on the front side of the second prism sheet 43 so as to cover the peripheral portion of the second prism sheet 43, so that light is transmitted from the periphery of the light guide plate 5 to the display panel 2 side. Can be prevented from leaking out.

  The LED unit 15 supplies light to the light guide plate 5. As shown in FIGS. 1 and 2, the LED unit 15 includes a flexible wiring substrate 16 as a light source substrate and a plurality of LEDs 17 as a light source. Each of the plurality of LEDs 17 is a light source having a substantially rectangular parallelepiped shape, and is mounted on the rear surface while being connected to a light source wiring 18 formed on the rear surface of the flexible wiring board 16. The LED 17 faces the one end surface 53 of the light guide plate 5, and the facing surface of the LED 17 is a light emission surface 171. The LED 17 emits light from the light exit surface 171 toward the light guide plate 5. The light emitted from the LED 17 enters the light guide plate 5 from the one end surface 53 and is emitted from the second main surface 52 toward the front surface of the light guide plate 5.

The spacer 9 is provided so as to be in contact with the surface of the flexible wiring board 16 opposite to the side to which the LED 17 is connected, that is, the front surface of the flexible wiring board 16. The spacer 9 is disposed on the side of the flexible wiring board 16 opposite to the side where the LEDs 17 are connected, and a predetermined interval is provided between the display panel 2 irradiated with the light emitted from the light source device 1 and the flexible wiring board 16. It is for providing.
FIG. 3 is a cross-sectional view showing a schematic configuration of the spacer 9. As shown in FIG. 3, the spacer 9 includes a light shielding substrate 91 and a heat conductive substrate 92.
The light-shielding substrate 91 is formed in a sheet shape with a resin such as PET, for example. This light-shielding substrate 91 is formed with a predetermined thickness by colored resin so as to have a light-shielding property. The heat conductive substrate 92 is formed in a sheet shape, for example, with metal or the like so that the heat conductivity is higher than that of the light shielding substrate 91. The thermally conductive substrate 92 is laminated on the light-shielding substrate 91 via the first bonding member 93. A second bonding member 94 (second bonding member) is laminated on the surface of the light-shielding substrate 91 opposite to the side on which the first bonding member 93 is provided. On the other hand, a third bonding member 95 (first bonding member) is laminated on the surface of the thermally conductive substrate 92 opposite to the side where the first bonding member 93 is provided. The first joining member 93, the second joining member 94, and the third joining member 95 are formed of an adhesive material or an adhesive. Here, what is solidified in the joined state is an adhesive, and what is elastic in the joined state is an adhesive.

  The spacer 9 is disposed such that the heat conductive substrate 92 is interposed between the light-shielding substrate 91 and the flexible wiring substrate 16, and the second bonding member 94 is the rear surface of the protruding portion 61 of the transparent substrate 6. The third bonding member 95 is in close contact with the front surface of the flexible wiring board 16. In this case, the second predetermined member provided on the side opposite to the side on which the flexible wiring substrate 16 is provided with respect to the spacer 9 serves as the overhanging portion 61 of the transparent substrate 6. And the 2nd joining member 94 and the 3rd joining member 95 are contacting the target object which the whole surface closely_contact | adheres, respectively.

  The light scattering sheet 41 scatters light emitted from the predetermined area 521 of the second main surface 52 of the light guide plate 5. The first prism sheet 42 and the second prism sheet 43 refract the scattered light when the light scattered by the light scattering sheet 41 passes through the prism sheets 42 and 43, and thereby the second main surface of the light guide plate 5. 52 is provided to emit light having high intensity in the normal direction.

  The frame 80 is a resin member formed in a substantially rectangular frame shape that houses the reflection sheet 11, the light guide plate 5, the light scattering sheet 41, the first prism sheet 42, the second prism sheet 43, and the spacer 9. An extending portion 82 that extends inward is formed on the inner peripheral surface of the frame 80. The extending part 82 is formed in a substantially U shape when viewed from the front, and one side close to the LED unit 15 is open. The display panel 2 is supported on the front surface of the extension portion 82.

Next, the operation of this embodiment will be described.
When the LED 17 is turned on, the light emission surface 171 emits light, and light enters the one end surface 53 of the light guide plate 5. The incident light is guided in the light guide plate 5 and emitted from the second main surface 52 toward the front side. The light emitted from the second main surface 52 passes through the light scattering sheet 41, the first prism sheet 42 and the second prism sheet 43 and is emitted toward the display panel 2. Thereby, the light source device 1 can illuminate the display panel 2 from the rear side.
Here, when the LED 17 is turned on, the LED 17 itself generates heat. However, most of the heat conducted from the LED 17 to the spacer 9 through the flexible wiring board 16 is more than that of the light shielding substrate 91 in the spacer 9. Heat is dissipated by the heat conductive substrate 92 having high conductivity.

  As described above, according to the present embodiment, the spacer 9 includes the light-shielding substrate 91 and the heat conductive substrate 92 that is stacked on the light-shielding substrate 91 and has a higher thermal conductivity than the light-shielding substrate 91. Therefore, the heat dissipation effect can be made higher than that of a spacer formed of a single resin. Therefore, it is possible to promote the heat dissipation of the amount of heat generated due to the light emission of the LED 17.

Further, since the heat conductive substrate 92 is interposed between the light shielding substrate 91 and the flexible wiring substrate 16, it is possible to easily conduct the heat generated by the LED 17 to the heat conductive substrate 92.
Further, since the spacer 9 is in contact with the display panel 2, the amount of heat can be transmitted to the display panel 2 having a surface area larger than that of the spacer 9, and more efficient heat dissipation can be achieved.
Further, since the entire surface of the spacer 9 opposite to the side on which the flexible wiring substrate 16 is provided with respect to the spacer 9 is in contact with the display panel 2, the contact area between the spacer 9 and the display panel 2 is reduced. It can be made as large as possible, and more efficient heat conduction is possible.

Note that the present invention is not limited to the above embodiment, and can be modified as appropriate. In the following description, the same parts as those in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.
For example, in the above-described embodiment, the case where the thermally conductive substrate 92 has a uniform thickness has been described as an example. However, a groove may be formed in a part of the thermally conductive substrate. For example, in the spacer 9A shown in FIG. 4, a plurality of grooves 97a are formed on the surface of the thermally conductive substrate 92a opposite to the side where the flexible wiring substrate 16 is provided with respect to the thermally conductive substrate 92a. Yes. The plurality of grooves 97a are formed in a region facing a predetermined member (for example, the first bonding member 93) provided on the opposite side of the thermally conductive substrate 92a. That is, the groove 97a is a separation area where the groove is separated from the predetermined member, and the area between the plurality of grooves 97a is a contact area where the groove 97a contacts the predetermined member.
FIG. 5 is a cross-sectional view of the surface along the line VV in FIG. As shown in FIG. 5, the groove 97 a is formed in a strip shape along the one end surface 53 of the light guide plate 5. Thereby, the light emitted from the one end surface 53 of the light guide plate 5 is prevented from entering the groove 97a.

As described above, since the plurality of grooves 97a as the separation regions are formed on the surface of the heat conductive substrate 92a opposite to the side on which the flexible wiring substrate 16 is provided with respect to the heat conductive substrate 92a. The heat dissipation effect can be further enhanced.
In addition, the spacer 9A is formed so that the communication ports at both ends of the groove 97a are arranged on a pair of edges intersecting the one end surface 53 of the light guide plate 5 in the heat conductive substrate 92a. The light leaking from the light plate 5 is difficult to enter from one communication port of the groove 97a. Thereby, it is possible to prevent the light leaking from the one end surface 53 of the light guide plate 5 from leaking outside through the groove 97a.

  In the above modification, the groove 97a of the spacer 9A is formed substantially parallel to the one end surface 53 of the light guide plate 5. However, the groove 97b of the spacer 9B is formed on the one end surface 53 of the light guide plate 5 as shown in FIG. You may form along the direction inclined with respect to it. In this case, the groove 97 b of the spacer 9 B is inclined with respect to the one end surface 53 of the light guide plate 5 so that the communication ports at both ends of the groove 97 b are formed at a pair of edges intersecting the one end surface 53 of the light guide plate 5. It is preferable to set an inclination angle.

Moreover, you may form the isolation | separation area | region of a heat conductive board | substrate so that the ratio per unit area may become larger in the peripheral part of the said heat conductive board | substrate than the center part of the heat conductive board | substrate. Specifically, like the spacer 9C shown in FIG. 7, the portion corresponding to the central portion of the heat conductive substrate 92c is narrowed, and a groove 97c that gradually becomes thicker toward the peripheral portion is formed, so that the heat conductivity is increased. The separation region is formed so that the peripheral portion has a higher ratio per unit area than the central portion of the substrate 92c.
In particular, as shown in FIG. 7, in the direction in which the groove 97c of the thermally conductive substrate 92c extends, the width of the groove 97c is narrowed at the center of the groove 97c and the width of the groove 97c is widened at both ends. The amount of heat conducted from the heat conductive substrate 92c to the atmosphere in the groove 97c can be easily conducted to the communication port which is the end of the groove 97c, and the heat dissipation efficiency can be further enhanced.

  Further, in the spacer 9D shown in FIG. 8, a plurality of wedge-shaped grooves 97d are formed in the heat conductive substrate 92d so that communication ports are formed at a pair of edges intersecting the one end surface 53 of the light guide plate 5. Is formed. Since each of the plurality of grooves 97d has only one communication port, the entire surface of the heat conductive substrate 92d on which the groove 97d is formed is connected without being divided by the groove 97d. It has a shape. In this case, in the direction in which the wedge-shaped groove 97d of the heat conductive substrate 92d extends, the width of the groove 97c is narrowed at the tip of the wedge-shaped groove 97c, and the width of the groove 97c is widened at the communication port. Therefore, similarly to the modification shown in FIG. 7, the amount of heat conducted from the heat conductive substrate 92d to the atmosphere in the groove 97d can be easily conducted to the communication port of the groove 97d, and the heat radiation efficiency can be further enhanced. In addition, since the entire surface of the thermally conductive substrate 92d where the groove 97d is formed is connected without being divided by the groove 97d, the groove 97d is formed in the thermally conductive substrate 92d. Since heat easily diffuses on the other side, the heat radiation efficiency can be further enhanced. Furthermore, a wedge-shaped groove 97d may be formed so that a communication port is formed at a pair of edges along the one end face 53 of the light guide plate 5 in the heat conductive substrate 92d. Heat dissipation efficiency can be increased.

  For example, like the spacer 9E shown in FIG. 9, it is good also considering all the areas which oppose LED17 as the groove | channel 97e. In this case, the amount of heat generated by the LED 17 is likely to be conducted along the thermally conductive substrate 92e, that is, the heat is easily conducted from the region overlapping the LED to the region not overlapping the LED. The generated heat can be efficiently radiated.

In the above embodiment, the case where the third bonding member 95 is interposed between the thermally conductive substrate 92 and the flexible wiring substrate 16 has been described as an example. It is also possible to directly contact the conductive substrate 92 and the flexible wiring substrate 16. In this case, it is possible to efficiently conduct heat from the flexible wiring board 16 to the thermally conductive board 92.
Further, in each of the above-described embodiments, a separation region may be provided so as to overlap the driver element 25 mounted on the protruding portion 61 of the rear transparent substrate 6. Thereby, it is possible to make it difficult to conduct heat to the driver element 25 when the amount of heat generated by the LED 17 is conducted to the display panel 2.

DESCRIPTION OF SYMBOLS 1 Light source device 2 Display panel 3 Case 5 Light guide plate 6 Transparent substrate 7 Transparent substrate 9 Spacer 11 Reflective sheet 15 LED unit 16 Flexible wiring substrate (light source substrate)
17 LED (light source)
18 Light source wiring 23 Optical sheet 24 Polarizing plate 31 Upper case 33 Lower case 41 Light scattering sheet 42 First prism sheet 43 Second prism sheet 51 First main surface 52 Second main surface 53 One end surface 80 Frame 91 Light-shielding substrate 92 Thermally conductive substrate 93 First joining member 94 Second joining member (second joining member)
95 Third joint member (first joint member)
97a Groove (spaced area)
100 Display device 171 Light exit surface

Claims (14)

A light guide plate having a thickness between the pair of main surfaces and emitting light incident from one end surface from a predetermined region of one of the pair of main surfaces;
A light source that emits light toward the one end surface of the light guide plate;
In the light source device comprising a light source substrate connected on one surface of the light source,
A spacer in contact with a surface of the light source substrate opposite to the side to which the light source is connected;
The light source device, wherein the spacer includes a light-shielding substrate having a light-shielding property, and a thermally conductive substrate that is stacked on the light-shielding substrate and has a higher thermal conductivity than the light-shielding substrate. A light guide plate having a thickness between the pair of main surfaces and emitting light incident from one end surface from a predetermined region of one of the pair of main surfaces;
A light source that emits light toward the one end surface of the light guide plate;
In the light source device comprising a light source substrate connected on one surface of the light source,
A spacer for providing a predetermined interval between the display panel disposed on the opposite side of the light source substrate to the side to which the light source is connected and the light source substrate;
The light source device, wherein the spacer includes a light-shielding substrate having a light-shielding property, and a thermally conductive substrate that is stacked on the light-shielding substrate and has a higher thermal conductivity than the light-shielding substrate. The light source device according to claim 1 or 2,
The light source device, wherein the spacer is disposed so that the thermally conductive substrate is interposed between the light shielding substrate and the light source substrate. The light source device according to claim 3.
Of the thermally conductive substrate, a surface opposite to the side where the light source substrate is provided with respect to the thermally conductive substrate is opposed to a predetermined member provided on the opposite side of the thermally conductive substrate. The light source device is characterized in that a contact region that contacts the predetermined member and a separation region that separates from the predetermined member are provided in the region to be operated. The light source device according to claim 4,
The heat conductive substrate has a groove provided on the opposite surface of the heat conductive substrate, and a region where the groove is provided is the separation region. The light source device according to claim 4 or 5,
The light source device according to claim 1, wherein the separation region of the thermally conductive substrate is formed in a band shape along the one end surface of the light guide plate. The light source device according to claim 4 or 5,
The spaced region of the thermally conductive substrate is formed such that an end portion is disposed on a side of the thermally conductive substrate that intersects the one end surface of the light guide plate. apparatus. In the light source device according to any one of claims 4 to 7,
The spaced-apart region of the thermally conductive substrate is formed such that the peripheral portion of the thermally conductive substrate has a larger ratio per unit area than the central portion of the thermally conductive substrate. Light source device. In the light source device according to any one of claims 4 to 8,
The light source device according to claim 1, wherein a region facing the light source is the separation region on the opposite surface of the thermally conductive substrate. In the light source device according to any one of claims 1 to 9,
The light source device, wherein the thermally conductive substrate is in direct contact with the light source substrate. In the light source device according to any one of claims 1 to 9,
The light source device, wherein the spacer is provided with a first bonding member that is interposed between the thermally conductive substrate and the light source substrate and contacts the light source substrate. The light source device according to any one of claims 1 to 11,
The thermally conductive substrate is provided with respect to the light-shielding substrate so that the spacer is in contact with a second predetermined member provided on the opposite side of the spacer from the side on which the light source substrate is provided. A light source device comprising a second bonding member provided on the side opposite to the side. The light source device according to any one of claims 1 to 12,
A display panel irradiated with light emitted from the light source device,
The display device, wherein the spacer is provided so as to be in contact with the display panel. The display device according to claim 13,
The display device, wherein the entire surface of the spacer opposite to the side on which the light source substrate is provided is in contact with the display panel.

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