JP5865065B2 - Surface light emitting device, image display device, and television receiver - Google Patents

Description

  The present invention relates to a surface light-emitting device having an edge light type backlight, and an image display device and a television receiver having the surface light-emitting device.

  Liquid crystal display devices are characterized by thinness and low power consumption, and in recent years, due to their improved display quality, they have become widespread as displays that replace conventional CRTs, and display images on television receivers (hereinafter referred to as TV receivers). It is also widely used as a device. Unlike a self-luminous device, a liquid crystal display device requires a backlight as a light source, and displays an image by controlling light transmittance determined by the electro-optical characteristics of the liquid crystal.

  There are two types of backlights: an edge light method (side light method, light guide plate method) and a direct type. In the case of a liquid crystal display device having an edge light type backlight, a backlight unit comprising a light guide plate, an optical sheet, and a light source module in a rectangular box-shaped chassis is arranged on the back surface of the liquid crystal display panel. The The light source module is formed by mounting a plurality of LEDs on the plane of an elongated substrate. When the backlight unit is an edge light type on both sides, the light source module is disposed on a pair of long side surfaces of a rectangular light guide plate. Light emitted from the LED and incident on the long side surface of the light guide plate exits from the main surface of the light guide plate and irradiates the back surface of the liquid crystal display panel.

FIG. 9 is a plan view showing a chassis 1 of a backlight unit having a conventional edge-type backlight, and FIG. 10 is an enlarged plan view of a corner portion of the chassis 1. In FIGS. 9 and 10, the light guide plate is omitted.
The chassis 1 includes a positioning pin 15 at a substantially central portion of both short edges and a positioning pin 17 at the ends of both long edges.
A light guide plate holder 12 is provided on each short side of the chassis 1, and the light guide plate holder 12 supports the light guide plate in a state where both short side portions of the light guide plate (not shown) are placed. Concave portions corresponding to protrusions 12a described later are formed on both short edges of the light guide plate. The light guide plate holder 12 has rectangular protrusions 12a at a plurality of locations along the longitudinal edge, and has positioning pin insertion holes 12b corresponding to the positioning pins 15 of the chassis 1 at a substantially central portion in the longitudinal direction. The light guide plate holder 12 is screwed to the chassis 1 with screws 16 at a plurality of positions in the longitudinal direction after the positioning pins 15 are inserted into the positioning pin insertion holes 12b and positioned on the chassis 1. Then, the light guide plate is placed on the light guide plate holder 12 and fixed in a state in which the corresponding concave portion of the light guide plate is fitted to the protrusion 12 a of the light guide plate holder 12.

  Heat spreaders 11 are provided on both long sides of the chassis 1. The heat spreader 11 has a rectangular plate shape that extends along the long side of the chassis 1 in a plan view, protrudes on both long side edges, and is fixed to the chassis 1 with screws 13 at a plurality of locations. Have And the light source support part 11e protrudes from the longitudinal edge part of the outer side of the heat spreader 11 at a right angle. The light source support 11e supports the light source module with the LED facing inward. The heat spreader 11 has a positioning pin insertion hole 11f corresponding to the positioning pin 17 at the end of the fixed portion 11d. The heat spreader 11 is screwed to the chassis 1 with screws 13 at a plurality of positions in the longitudinal direction after the positioning pins 17 are inserted into the positioning pin insertion holes 11f and positioned on the chassis 1. An LED is provided on the light source support portion 11 e, and heat generated by the LED is transferred through the heat spreader 11 and radiated from the bottom surface of the chassis 1. As shown in FIG. 9, the heat spreader 11 and the light guide plate holder 12 are fitted at the corners of the chassis 1.

11 is a schematic plan view showing the arrangement of the light guide plate 2, the heat spreader 11, and the light guide plate holder 12. FIG. 12 is a schematic perspective view showing the arrangement of the light guide plate 2, the heat spreader 11, and the light guide plate holder 12.
As shown in FIG. 11, when the light guide plate holder 12 is attached to the chassis 1 with the positioning pins 15, an attachment error a occurs. When the heat spreader 11 is attached to the chassis 1 by the positioning pins 17, an attachment error b occurs. Therefore, as shown in FIGS. 11 and 12, the error in the clearance between the light guide plate 2 and the LED 4 is (a + b + α) when the component tolerance is α. As described above, since the clearance is affected by the mounting error of the parts, the variation range is large, and it is difficult to keep the clearance constant. If the clearance error is large, there will be quality problems such as uneven brightness in the surface direction of the liquid crystal display panel and brightness (optical characteristics) error between products.

In Patent Document 1, in order to keep the clearance between the light guide plate and the LED constant, a structure in which the heat spreader is slid on the chassis is provided, the light guide plate and the heat spreader are fixed with an adhesive, and the light guide plate and the LED are integrated. An invention of a backlight unit that has been made to move is disclosed.
Patent Document 2 discloses an invention of a planar illumination device in which a light guide plate and a light source are each fixed to a heat spreader with screws so that the clearance between the light guide plate and the LED is kept constant.
Patent Document 3 discloses a planar illumination in which the light guide plate and the LED are fixed and integrated with a U-shaped cover (clip shape) so that the clearance between the light guide plate and the LED is kept constant. An apparatus invention is disclosed.

JP 2011-134715 A JP 2009-276741 A JP 2004-39570 A

In the case of Patent Document 1, it is necessary to fix the light guide plate and the heat spreader with an adhesive, and there is a problem that the operation is complicated.
In the case of Patent Document 2, it is necessary to provide screw holes in the light guide plate, which leads to an increase in the cost of the light guide plate and causes problems such as uneven brightness and poor display quality.
In the case of Patent Document 3, since the bar-shaped light source is covered with the cover member, there is a problem that it is difficult to radiate heat.

  The present invention has been made in view of such circumstances, and with a simple configuration, the clearance error between the light guide plate and the light source is reduced to make the light incident efficiency into the light guide plate constant, without impairing heat dissipation, A surface light-emitting device capable of suppressing luminance unevenness in the surface direction of the display panel and a luminance error between products and improving the luminance by reducing the design value of the clearance, and an image display including the surface light-emitting device An object is to provide a device and a television receiver.

A surface light emitting device according to the present invention includes a substrate having a plurality of light sources, a rectangular plate shape, and a light source support portion that protrudes perpendicularly from a long edge of the rectangular plate, and the light source support portion allows the substrate to be mounted. a heat radiating plate for radiating heat of the light source support, and a light guide plate is emitted from the main surface by incident light from the light source from the side, a light guide plate supporting plate for supporting the light guide plate, the heat radiating plate rectangular plate portion and the light guide plate supporting plate is a surface emitting device and a chassis that is attached to the bottom surface, Ri fixed tare the radiator plate to the light guide plate supporting plate, said heat sink, and the side wherein the substrate is characterized by fixed tare Rukoto to the chassis in a state of inserting the screw into the long holes in opposite directions.

  In the surface light emitting device according to the present invention, the heat radiating plate is fixed to the light guide plate support plate by pins.

  In the surface light emitting device according to the present invention, the light guide plate and the light guide plate support plate are made of a material having substantially the same thermal expansion coefficient.

In the surface light emitting device according to the present invention, the light guide plate is configured so that light from the light source is incident from one side surface, and an end portion of the heat radiating plate on the light guide plate support plate side is connected to the light guide plate support plate. The pin is configured to overlap with the end portion on the light source side, and the pin is provided near the edge portion on the light source side on the light guide plate support plate side .

  An image display device according to the present invention includes the surface light-emitting device described above and a display panel that displays an image using light from the surface light-emitting device.

  A television receiver according to the present invention includes a receiving unit that receives a television broadcast signal and the above-described image display device, and the receiving unit receives the television broadcast signal to the display panel of the image display device. A TV image is displayed.

In the present invention, the heat sink and the light guide plate support plate are integrated, the light guide plate support plate is also integrated with the light guide plate, that is, the heat sink, the light guide plate support plate, and the light guide plate are integrated. Even if there is an error in attaching the light guide plate support plate to the chassis, the clearance between the light guide plate and the substrate is not affected. Accordingly, the clearance error is based on only the mounting error of the heat sink to the light guide plate support plate and the component tolerances of the heat sink, light guide plate support plate, and light guide plate, and can be reduced. Therefore, the light incident efficiency to the light guide plate is constant. Since the clearance error is reduced, the design value of the clearance can be reduced, thereby improving the incident efficiency.
In the surface light emitting device of the present invention, the workability is improved by positioning the heat radiating plate on the light guide plate support plate and fixing it to the chassis with pins. And unlike patent document 2, a brightness nonuniformity does not arise by providing a screw hole in a light-guide plate. Furthermore, unlike patent document 3, the heat dissipation of a heat sink is also favorable.

  In the present invention, since the heat sink has a long screw insertion hole in the direction in which the incident side surface of the light guide plate and the substrate face each other, the heat sink can be slid in this direction and positioned on the light guide plate support plate. . Therefore, the position error of the screw hole on the chassis for screwing the heat radiating plate is absorbed, and the error of the clearance between the light guide plate and the substrate can be reduced.

  In the present invention, since the light guide plate and the light guide plate support plate are made of materials having substantially the same thermal expansion coefficient, it is possible to suppress a change in the clearance between the light guide plate and the substrate during thermal expansion and contraction.

  In the present invention, in the case of the one-side edge light system, since the distance between the portion where the heat sink is fixed to the light guide plate support plate and the plane of the substrate supported by the heat sink is short, the light guide plate during thermal expansion and contraction It is possible to suppress a change in the clearance between the substrate and the substrate.

  In the image display device of the present invention, since the light incident efficiency to the light guide plate of the surface light emitting device is stable, the luminance unevenness of the display panel and the luminance error between products are suppressed. Since the clearance error can be reduced, the design value of the clearance can be reduced, whereby the incident efficiency can be improved, so that the luminance can be improved.

  In the television receiver of the present invention, since the light incident efficiency to the light guide plate of the surface light emitting device is stable, the luminance unevenness of the display panel and the luminance error between products can be suppressed, and the luminance can be improved. .

According to the surface light emitting device of the present invention, the heat sink and the light guide plate support plate are integrated, and since the heat sink, the light guide plate support plate, and the light guide plate are integrated, the light guide plate support plate is attached to the chassis. Even if there is an error, the clearance between the light guide plate and the substrate having the light source is not affected. Accordingly, the clearance error is based on only the mounting error of the heat sink to the light guide plate support plate and the component tolerances of the heat sink, light guide plate support plate, and light guide plate, and can be reduced. Therefore, the light incident efficiency to the light guide plate is constant. Therefore, in the image display device and the television receiver provided with the surface light emitting device of the present invention, luminance unevenness in the surface direction of the display panel and luminance error between products are suppressed. Furthermore, since the clearance error can be reduced, the design value of the clearance can be reduced, whereby the incident efficiency can be improved, and the luminance of the display panel can be improved.
And according to the surface emitting device of this invention, workability | operativity becomes favorable by positioning a heat sink with the said light-guide plate support plate with a pin, and fixing to a chassis. And unlike patent document 2, a brightness nonuniformity does not arise by providing a screw hole in a light-guide plate. Furthermore, unlike patent document 3, the heat dissipation of a heat sink is also favorable.

It is a perspective view which shows the television receiver which concerns on embodiment of this invention. 1 is a perspective view showing a liquid crystal display device according to an embodiment of the present invention. 1 is a longitudinal sectional view showing a liquid crystal display device according to an embodiment of the present invention. It is a perspective view which shows the attachment part to the chassis of the heat spreader and light guide plate holder which concern on embodiment of this invention. FIG. 5 is an enlarged view of FIG. 4. It is sectional drawing which shows the attachment part to the light-guide plate holder of a heat spreader. It is a typical top view showing arrangement of a light guide plate, a heat spreader, and a light guide plate holder. It is a typical perspective view which shows arrangement | positioning of a light-guide plate, a heat spreader, and a light-guide plate holder. It is a top view which shows the chassis of the backlight unit which has the conventional edge type | mold backlight. It is an enlarged plan view which shows the corner | angular part of the chassis of the conventional backlight unit. It is a typical top view which shows arrangement | positioning of the light-guide plate of the conventional backlight unit, a heat spreader, and a light-guide plate holder. It is a typical perspective view which shows arrangement | positioning of the light-guide plate of the conventional backlight unit, a heat spreader, and a light-guide plate holder.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
FIG. 1 is a perspective view showing a television receiver (television receiver: hereinafter referred to as TV receiver) 100 according to the present invention. The TV receiver 100 includes a liquid crystal display device (image display device) 10 including a backlight unit 9 (surface light emitting device), which will be described later, cabinets 20 and 30 that house the liquid crystal display device 10 in between, a power supply 40, A tuner 50 and a stand 60 are provided. The liquid crystal display device 10 has a horizontally long and substantially rectangular parallelepiped shape as a whole, and is housed in the cabinets 20 and 30 in a vertically placed state.

FIG. 2 is a perspective view showing the liquid crystal display device 10, and FIG. 3 is a longitudinal sectional view showing the liquid crystal display device 10.
The liquid crystal display device 10 includes a liquid crystal display panel 7 and a one-side edge light type backlight unit 9 disposed on the back side of the liquid crystal display panel 7. A bezel 8 is attached to the display surface side of the liquid crystal display panel 7. During the display operation, planar light is emitted from the backlight unit 9, and the back surface of the liquid crystal display panel 7 is illuminated by the light.
The liquid crystal display panel 7 includes a liquid crystal layer, a pair of glass substrates, and a polarizing plate. The pair of glass substrates are bonded to each other with a sealing material interposed therebetween, and a liquid crystal layer is sandwiched therebetween. And the polarizing plate is each distribute | arranged on the surface on the opposite side to the liquid crystal layer side of a pair of glass substrate.

  The backlight unit 9 includes a chassis 1, a light guide plate 2, a light source module 5, and an optical sheet 6. The chassis 1 has a substantially box shape with the liquid crystal display panel 7 side opened. The chassis 1 houses the light guide plate 2, the optical sheet 6, and the light source module 5.

  The light guide plate 2 has a rectangular plate shape, and includes a main surface 2a facing the liquid crystal display panel 7 side, a back surface opposite to the main surface 2a and facing the chassis 1, a pair of long side surfaces, and a pair of short side surfaces. Have. The side surface 2b, which is one long side surface, functions as a light incident surface for introducing light into the light guide plate 2, and the light introduced from the side surface 2b into the light guide plate 2 is the main surface of the light guide plate 2. The light is emitted from 2a toward the liquid crystal display panel 7 side. Further, in both short edges of the light guide plate 2, recesses corresponding to protrusions 12 a described later are formed.

  The optical sheet 6 is a sheet group including a diffusion sheet, a lens sheet, a DBEF sheet (reflective polarizing sheet), and the like, and is placed on the main surface 2 a of the light guide plate 2. The optical sheet 6 diffuses and collects light emitted from the main surface 2 a of the light guide plate 2.

  The light source module 5 is for generating light to be introduced into the light guide plate 2, and is disposed on the side surface 2 b side of the light guide plate 2. The light source module 5 has a substrate 3, and a plurality of LEDs 4 are mounted on the plane of the substrate 3. The substrate 3 extends along the long side of the main surface 2a, and is arranged so that the plurality of LEDs 4 mounted on the plane face the side surface 2b of the light guide plate 2.

4 is a perspective view showing a mounting portion of the heat spreader 11 and the light guide plate holder 12 to the chassis 1 in the backlight unit 9, FIG. 5 is an enlarged view of FIG. 4, and FIG. 6 is an attachment of the heat spreader 11 to the light guide plate holder 12. It is sectional drawing which shows a part. 4 to 6, the light guide plate is omitted.
Similar to the conventional backlight unit described above, the light guide plate holders 12 are provided on both short sides of the chassis 1 and support the light guide plate 2 in a state where both short side portions of the light guide plate 2 are placed. . The light guide plate holder 12 has rectangular protrusions 12a at a plurality of locations along the longitudinal edge, and has positioning pin insertion holes 12b corresponding to the positioning pins 15 of the chassis 1 at a substantially central portion in the longitudinal direction. Positioning pins 14 are provided at the edge. The light guide plate holder 12 is positioned on the chassis 1 by inserting the positioning pins 15 of the chassis 1 into the positioning pin insertion holes 12b, and then screwed to the chassis 1 with screws 16 at a plurality of locations in the longitudinal direction. Then, the light guide plate 2 is placed on the light guide plate holder 12 and fixed in a state where the corresponding concave portion of the light guide plate is fitted to the protrusion 12a of the light guide plate holder 12. The light guide plate 2 and the light guide plate holder 12 are preferably made of a material having substantially the same thermal expansion coefficient, for example, a case where both are made of polycarbonate.

  Since the backlight unit 9 of the present embodiment is a one-side edge light type, the heat spreader 11 is provided on one long side of the chassis 1. The heat spreader 11 has a rectangular plate shape that extends along the long side of the chassis 1 in a plan view, protrudes on both long side edges, and is fixed to the chassis 1 with screws 13 at a plurality of locations. Have And the light source support part 11e protrudes from the longitudinal edge part of the outer side of the heat spreader 11 at a right angle. The light source support 11e supports the light source module 5 with the LED 4 facing inward. A screw insertion hole 11a through which the screw 13 is inserted has a long oval shape in the direction toward the end surface 2b of the light guide plate 2 (the vertical direction in FIGS. 4 and 5) at each screw-fixed portion of the fixing portions 11c and 11d. Have. At the end of the heat spreader 11 on the light guide plate holder 12 side, there is a positioning pin insertion hole 11b through which the positioning pin 14 is inserted.

The end of the heat spreader 11 is overlapped with the end of the light guide plate holder 12, and the positioning pins 14 provided in the light guide plate holder 12 are inserted into the positioning pin insertion holes 11 b of the heat spreader 11, so that the heat spreader 11 is placed on the light guide plate holder 12. Position to. As shown in FIG. 6, the lower end of the light guide plate holder 12 extends toward the heat spreader 11, the upper end of the heat spreader 11 extends toward the light guide plate holder 12, and the heat spreader 11 and the light guide plate holder 12. Are fitted to be flush with each other. Since the screw insertion hole 11a has an oval shape and has play as described above, the heat spreader 11 can be positioned on the light guide plate holder 12 by sliding the heat spreader 11 in the vertical direction. Therefore, positioning is performed without being affected by the dimensional tolerance of the screw hole provided in the chassis 1 for screwing the screw 13. The heat spreader 11 is screwed to the chassis 1 with screws 13 at a plurality of locations in the longitudinal direction.
The configuration is not limited to the case where the heat spreader 11 and the light guide plate holder 12 are configured to be flush with each other at the overlapping portion. The positioning is not limited to the case where the positioning pin 14 is inserted into the positioning pin insertion hole 11b for positioning, and a notch is provided on one of the heat spreader 11 and the light guide plate holder 12, and the other is a projection that is engaged with the notch. The heat spreader 11 may be positioned on the light guide plate holder 12.

7 is a schematic plan view showing the arrangement of the light guide plate 2, the heat spreader 11, and the light guide plate holder 12. FIG. 8 is a schematic perspective view showing the arrangement of the light guide plate 2, the heat spreader 11, and the light guide plate holder 12. As shown in FIG.
As shown in FIG. 7, when the light guide plate holder 12 is attached to the chassis 1 with the positioning pins 15, an attachment error a occurs. However, since the heat spreader 11 is integrated with the light guide plate holder 12, the position of the positioning pin 15 also moves by the amount of the mounting error a. Since the light guide plate 2 is also integrated with the light guide plate holder 12, the mounting error a does not affect the clearance between the light guide plate 2 and the LEDs 4. Further, as described above, the screw insertion hole 11a has an oval shape and absorbs the dimensional tolerance of the screw hole for attaching the heat spreader 11 of the chassis 1, so that the clearance varies depending on the attachment of the heat spreader 11 to the chassis 1. To be suppressed.
Therefore, the clearance error between the light guide plate 2 and the LED 4 is (b + α) where b is the mounting error of the heat spreader 11 to the light guide plate holder 12 and the component tolerance is α, and the conventional error shown in FIGS. It is reduced compared with (a + b + α), which is an error in the clearance of the backlight unit.

  In this embodiment, since the light guide plate 2 and the light guide plate holder 12 are both made of polycarbonate and have the same thermal expansion coefficient, the light guide plate 2 and the light guide plate holder 12 are guided by the difference in expansion and contraction during the thermal expansion and contraction. The clearance between the light plate 2 and the LED 4 does not change. The light guide plate 2 and the light guide plate holder 12 are not limited to the case where the light guide plate 2 and the light guide plate holder 12 are made of the same material, but it is preferable from the above viewpoint to use materials having substantially the same thermal expansion coefficient.

It is preferable that a protrusion 12a that fits with the light guide plate 2 of the light guide plate holder 12 is also provided on the light source module 5 side so as not to be affected by the thermal expansion and contraction of the clearance.
Then, by shortening the distance between the positioning pin 14 and the plane of the substrate 3 supported by the heat spreader 11, the change in the clearance can be suppressed during thermal expansion and contraction.

As described above, in the present embodiment, since the error in the clearance between the light guide plate 2 and the LED 4 is reduced, in the liquid crystal display device 10, the light source module 5 from the backlight unit 9 to the light guide plate 2 is used. The light incident efficiency is made constant, and the luminance unevenness in the surface direction of the liquid crystal display panel 7 and the luminance error between products are suppressed.
Since the clearance error is reduced, the design value of the clearance can be reduced, whereby the incident efficiency can be improved and the luminance of the liquid crystal display panel 7 can be improved.
Moreover, in the backlight unit 9 of this Embodiment, after positioning the heat spreader 11 to the light-guide plate holder 12 from the positioning pin 14, it fixes to the chassis 1, Therefore Workability | operativity is favorable. And as in Patent Document 2, luminance unevenness does not occur by providing screw holes in the light guide plate 2. Furthermore, unlike Patent Document 3, the heat spreader 11 has good heat dissipation.

In the present embodiment, the case where the backlight unit 9 is a one-side edge light system is described, but the present invention is not limited to this, and the surface light emitting device of the present invention is a double-side edge light type backlight. It can also be applied to.
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is not intended to include the above-described meanings, but is intended to include meanings equivalent to the claims and all modifications within the scope of the claims.

1 Chassis 2 Light guide plate 3 Substrate 4 LED
DESCRIPTION OF SYMBOLS 5 Light source module 6 Optical sheet 7 Liquid crystal display panel 9 Backlight unit 10 Liquid crystal display device 11 Heat spreader 11a Screw insertion hole 11b Positioning pin insertion hole 11c, 11d Fixing part 11e Light source support part 12 Light guide plate holder 12a Protrusion part 12b Positioning pin insertion hole 13, 16 Screws 14, 15 Positioning pins 20, 30 Cabinet 40 Power supply 50 Tuner 60 Stand 100 TV receiver

Claims (6)

Radiating a substrate having a plurality of light sources, a rectangular plate shape, has a light source support portion protruding perpendicularly from the longitudinal edges of the rectangular plate, the heat of the light source to support the substrate by the light source support part A heat radiating plate, a light guide plate that emits light from the light source from the side surface and exits from the main surface, a light guide plate support plate that supports the light guide plate, a rectangular plate portion of the heat radiating plate , and the light guide plate support plate there a surface emitting device and a chassis that is attached to the bottom surface,
Ri fixed tare the radiator plate to the light guide plate supporting plate,
The heat sink surface emitting device and the side surface and wherein said substrate fixed tare Rukoto to the chassis in a state of inserting the screw into the long holes in opposite directions.   The surface light-emitting device according to claim 1, wherein the heat radiating plate is fixed to the light guide plate support plate by a pin. The light guide plate and the light guide plate support plate, a surface light-emitting device according to claim 1 or 2, characterized in that it consists of a material having approximately the same thermal expansion coefficient. The light guide plate is configured to receive light from the light source from one side surface,
The light guide plate support plate side end of the heat sink is configured to overlap the light source plate end of the light guide plate support plate,
The surface emitting device according to claim 2 , wherein the pin is provided near an edge on the light source side on the light guide plate support plate side . A surface light emitting device according to any one of claims 1 to 4 ,
An image display device comprising: a display panel that displays an image using light from the surface light emitting device. A receiver for receiving a television broadcast signal;
An image display device according to claim 5 ,
The television receiving device, wherein the receiving unit receives the television broadcast signal and displays a television image on the display panel of the image display device.

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