JP2012037605A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide technique to reduce thermal interference between a plurality of heat sources of an image display device such as a liquid crystal display device and improve dust resistance and rigidity of the device.SOLUTION: A heat spreader is provided to the inside of a bottom frame of a display panel module to form a double-sheet-metal structure. An LED substrate mounting an LED is provided on an opposite side surface of the bottom frame in the heat spreader. An LED drive substrate, a power source substrate, a signal substrate, etc. are provided to the outside of the bottom frame. A space with a predetermined size is provided between the bottom frame and the heat spreader, thereby reducing thermal interference between the LED substrate, the LED drive substrate, the power source substrate, and the signal substrate, etc., and improving dust resistance and rigidity.

Description

  The present invention relates to a video display device such as a liquid crystal display device, and more particularly to a video display device in which thermal interference between circuit boards is reduced by a structural device.

In video display devices using flat panels such as liquid crystal display devices, it is required to increase the size and thickness of the device, so that thermal interference between internal circuit boards is prevented and the rigidity of the device is improved. Technology to do this is important.
Patent Document 1 discloses a technique for ensuring the rigidity of a frame portion in a display device having a structure in which a peripheral portion of a display panel is directly held by a frame portion of a cabinet.

JP 2009-134269 A

  In the case of a liquid crystal display device, a metal chassis is attached to the bottom frame that covers the back side of the panel module, and a circuit board such as a liquid crystal backlight drive board, a power supply board, or a signal processing board is mounted on the chassis. There are many.

On the other hand, it is conceivable that the chassis is removed to form a sheet metal structure with only the bottom frame, and the circuit board is directly attached to the bottom frame. However, the chassis has an effect of dissipating heat generated by the circuit board to prevent temperature rise and prevent thermal interference with the inside of the panel module. It also has the effect of enhancing the rigidity of the device. Furthermore, it also has an effect of preventing dust from entering the inside of the panel module through the hole in the bottom frame. Accordingly, simply removing the chassis causes problems related to temperature rise, rigidity, and dust resistance.
The present invention provides a video display device in which thermal interference between circuit boards is reduced in view of the above problems. The present invention also provides an image display device with enhanced dustproofness or enhanced rigidity.

The present invention is a video display device having a display panel module for displaying video,
The display panel module includes a display panel, a light source, a light source substrate to which the light source is attached, and a holding member to which a light guide plate for guiding the light from the light source substrate and the light source toward the display panel is attached. And a bottom frame of a metal material to which the holding member is attached and disposed on the back side of the display panel module,
A light source driving circuit board for driving the light source is provided on the back side of the bottom frame;
A space having a predetermined size is provided between the holding member and the bottom frame.
Further, in the above-described video display device, the holding member includes a plurality of divided members, and the holding members are configured by connecting the members to each other. Moreover, you may provide the protrusion part for attaching the fixing member which fixes the said bottom frame in the edge part of this member.

  ADVANTAGE OF THE INVENTION According to this invention, the thermal interference between circuit boards or between a circuit board and a display panel module can be reduced, and there exists an effect that the temperature rise inside an apparatus can be prevented. It also has the effect of improving dust resistance and further enhancing rigidity.

It is an external view from the front side of the video display apparatus in one Example of this invention. It is the exploded view seen from the back side of the picture display device in one example of the present invention. It is an exploded view of the display panel module in one Example of this invention. It is a 1st sectional view of a display panel module in one example of the present invention. It is a rear view of the heat spread in one Example of this invention. It is a rear view of the display panel module in one Example of this invention. It is 2nd sectional drawing of the display panel module in one Example of this invention. It is a 3rd sectional view of the display panel module in one example of the present invention. It is the figure which looked at the back side of bottom frame 148. It is a disassembled perspective view of the backlight device according to the present embodiment. It is a disassembled perspective view of the light-guide plate assembly 150A or 150B. It is a vertical direction sectional view of one light guide plate portion in the light guide plate assembly.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an external view from the front side of a video display device 1 according to an embodiment of the present invention. FIG. 2 is an exploded view seen from the back side of the video display device 1 according to an embodiment of the present invention.

  As shown in FIG. 2, the video display device 1 includes a punching metal 11, a decoration panel 12, a bezel 13, a display panel module 14, and a back cover 15 in order from the front side. Among these, the punching metal 11 and the decoration panel 12 are exterior parts on the front side of the video display device 1 as shown in FIG. On the other hand, the back cover 15 is an exterior part on the back side of the video display device 1. The vessel 13 fixes the decoration panel 12 and the display panel module 14 to each other and is attached with a speaker (not shown), for example. When the display panel module 14 is a liquid crystal panel module, it has a liquid crystal panel cell and a backlight device for irradiating the liquid crystal panel cell with light, as will be described later. The present embodiment can be applied to a video display device using a display panel module other than the liquid crystal panel module. Hereinafter, a case where the display panel module 14 is a liquid crystal panel module as a display device will be described as an example. As shown in FIG. 1, the liquid crystal panel cell 142 included in the display panel module 14 is directed to the front side of the video display device.

Next, the structure of the display panel module 14 in the present embodiment will be described in detail with reference to FIG. 3 and subsequent drawings.
FIG. 3 is an exploded view of the display panel module 14 in one embodiment of the present invention. In FIG. 3, the display panel module 14 is drawn in the same direction as FIG. 2, that is, from the back side of the image display device 1.

  In FIG. 3, a bottom frame 148 is provided on the rearmost side of the display panel module 14. The bottom frame 148 is made of, for example, a metal such as iron or aluminum, and is used as an exterior of the display panel module 14. Various circuit elements for operating the video display device are attached to the back side (the front side in the figure) of the bottom frame 148.

  Here, circuit elements attached to the bottom frame 148 will be described with reference to FIG. FIG. 9 is a view of the rear side of the bottom frame 148. On the lower right side of the bottom frame 148, for example, a tuner (not shown) that receives a television signal and the received television signal is demodulated and decoded. Processing, scaling processing to increase / decrease the number of pixels of the decoded signal in the horizontal and vertical directions, frame rate conversion processing to convert the frame rate (vertical frequency), other contrast adjustment, brightness adjustment and color adjustment A signal board 91 including a processor (not shown) for performing various image quality adjustment processes such as the above is provided. The signal board 91 also includes an encoder (not shown) for encoding and compressing the decoded signal. The signal encoded and compressed by the encoder is supplied to the HDD / removable HDD 92 and recorded.

  The HDD / removable HDD 92 includes a slot (not shown) in which, for example, an HDD built in the video display device and / or a removable HDD removable from the video display device is inserted in the vicinity of the signal board 91. It is out. The processor of the signal board 91 also has a function of decoding the video signal reproduced by the HDD / removable HDD 92.

  The processor of the signal board 91 also has a function of detecting the characteristics of a video signal such as a television signal. For example, the average luminance level, the maximum luminance level, the minimum luminance level for one frame of the video signal, A luminance histogram indicating the frequency of pixel appearance for each luminance range in the video signal is detected. Further, the processor detects the characteristics of these videos not only for one frame of the video signal but also for each display area obtained by dividing the display screen (one frame). These detected video features are output to the area control board 93 together with the video signals whose image quality has been adjusted. Each of the divided display areas corresponds to each area of the divided backlight device.

  The area control board 93 is a circuit for controlling the backlight device. Here, the backlight device is divided into a plurality of areas as will be described later, and is configured such that the intensity of light can be controlled for each area. That is, the area control board 93 individually determines the light emission intensity of the light source (LED: Light Emitting Diode) corresponding to each area of the backlight device based on the video characteristics (particularly the maximum luminance of each display area) detected by the processor. To control. For example, if the maximum luminance detected in a certain display area is 127 in 8-bit expression and the maximum gradation that can be expressed by the liquid crystal panel cell is 255 in 8-bit expression, the emission intensity of the area corresponding to the display area is , ½ of the maximum light intensity that the LED can output. When the maximum luminance is 64, the light intensity of the LED in the area is set to 1/4. In this way, the area control board 93 generates a backlight control signal for controlling the backlight device and outputs the backlight control signal to the LED drive board 95.

The LED drive board 95, which is a light source drive board, is provided on the left side of the bottom frame 148, for example, so that the light intensity indicated by the backlight control signal can be obtained based on the backlight control signal from the area control board 93. To drive the LED.
Further, if the light intensity is reduced according to the maximum luminance of the video as described above, the brightness of the image inherent to the video signal cannot be expressed. In the area control board 93, the video signal is multiplied by the inverse of the coefficient (1/2, 1/4) for controlling the light intensity as the amplification degree of the video signal so as to compensate for the decrease in the light intensity. .

The video signal thus amplified by the area control board 93 is supplied to, for example, a timing controller (T-CON) board 94 provided near the upper end of the bottom frame 148, and the video signal is supplied to each pixel of the liquid crystal panel cell. Drive to supply.
The power supply circuit 96 is disposed at substantially the center of the bottom frame 148, rectifies and converts the supplied commercial power supply, and converts the signal board 91, HDD / removable HDD 92, area control board 93, and T-CON board 94. , And supplied to each circuit element such as the LED driving board 95.

As described above, since the bottom frame 148 is made of metal, the bottom frame 148 has an action of radiating heat generated by the signal board 91, the LED driving board 95, the power supply board 96, and the like, and an action of improving the rigidity of the video display device 1. Have.
Inside the bottom frame 148 (the front side of the video display device 1), a heat spread 147, which is a component constituting the backlight device of the display panel module 14 and is a plate-like holding member, is provided. Similarly to the bottom frame 148, the heat spread 147 is also made of a metal such as iron or aluminum. The configuration of the backlight device including the heat spread 147 will be described with reference to FIGS.

  FIG. 10 is an exploded perspective view of the backlight device including the heat spread 147, and shows the relationship between the heat spread 147 and the light guide plate assembly 150. 10, both are drawn from the opposite direction to FIG. 2, that is, from the front side of the video display device 1. In FIG. As shown in the figure, on the liquid crystal panel cell 142 side (right front side in the figure) of the heat spread 147, for example, three light guide plate assemblies 150 are arranged along the vertical direction (vertical direction in the figure) of the liquid crystal panel cell 142. Yes. Each light guide plate assembly 150 is attached and held by a heat spread 147. Each light guide plate assembly 150 is configured by connecting two sub light guide plate assemblies 150A and 150B in the horizontal direction of the liquid crystal panel cell 142 (the horizontal direction in the figure). In FIG. 10, only the lowermost light guide plate assembly 150 is denoted by the sub light guide plate assembly for the sake of simplicity.

  Each sub light guide plate assembly 150A (or 150B) includes an LED substrate 1471 on which LEDs 151 are arranged and mounted in the horizontal direction (left-right direction in the drawing) on the liquid crystal panel cell 142 side, as shown in the exploded perspective view of FIG. A light guide plate 1473 (1473A and 1473B in the figure) made of a transparent resin such as acrylic, on which light from the LED 151 mounted on the LED substrate 1471 is incident, and a bottom surface of the light guide plate 1473 (in the light guide plate 1473) And a reflection sheet 1472 arranged on the left back side in the drawing.

  Two rows of LEDs 151 are mounted in the horizontal direction on the LED substrate 1471, and a hole 152 into which each LED 151 is inserted is provided in the light incident portion of the light guide plate 1473. Further, a hole 156 larger than the hole into which the LED is inserted is provided, and a pin mold, which will be described later, is inserted into the hole 156 to fix the light guide plate 1473 to the heat spread 147. Here, each light guide plate assembly 150A (or 150B) has two light guide plates, that is, a light guide plate 1473A and a light guide plate 1473B, and is opposite to the end portion (the end portion where the hole 152 is provided) of the light guide plate 1473B. Side end) is superimposed on the light incident portion (portion where the hole 152 is provided) of the light guide plate 1473A.

  Although only the hole 152 and the hole 156 of the light guide plate 1473B are shown in FIG. 11, it is assumed that the hole 152 and the hole 156 are similarly provided in the light guide plate 1473A. Each of the light guide plates 1473A and 1473B has a long rectangular shape in the horizontal direction (left-right direction in the figure) of the liquid crystal panel cell 142, and each is further divided into six parts by grooves 153. Each portion of the light guide plate divided into six corresponds to the “area” of the backlight device described above. That is, in the backlight device according to the present embodiment, since one light guide plate assembly 150 has four light guide plates 1473 having six areas, each light guide plate assembly has 24 areas. Yes.

  In addition, since the two light guide plates 1473 having six areas are arranged in the horizontal direction and six in the vertical direction, the liquid crystal panel cell 142 has a total of 72 areas. Of course, this number of areas is an example, and it may be more or less than this. For example, 96 divisions and 128 divisions are possible. In this embodiment, three LEDs 151 are arranged as light sources corresponding to each area, but one or two LEDs may be provided. By individually controlling the light intensity from one or a plurality of LEDs corresponding to each area for each area, the light intensity from the backlight device can be locally changed (that is, for each area). In the following, each part divided by the groove 153 may be referred to as a “light guide block”.

Next, an optical action related to one light guide plate 1473 in each light guide plate assembly 150 will be described with reference to FIG. FIG. 12 is a vertical sectional view of one light guide plate portion of the light guide plate assembly 150.
As shown in FIG. 12, the LED 151 mounted on the LED substrate 1471 is inserted into the hole 152 of the light guide plate 1473, and the light guide plate 1473 is opposed to the end from which the light from the LED 151 is incident. It has a wedge shape that gradually decreases in thickness toward the tip. Thereby, the luminance distribution of the emitted light is made uniform from the light incident end portion to the tip end portion.

  Light from the LED 151 is incident on the thicker end, is multiple-reflected in the light guide plate 1473, and is emitted from the upper surface toward the liquid crystal panel cell (arrow direction in the figure). In FIG. 12, the light transmitted from the bottom surface of the light guide plate 1473 to the outside of the light guide plate is reflected by the reflection sheet 1472 disposed at the lower portion of the bottom surface of the light guide plate 1473 and returns to the light guide plate 1473 again. The light is emitted from the upper surface (light emitting surface) of 1473. The light use efficiency is improved by the action of the reflection sheet 1472. With such a configuration, a point light source such as an LED is converted into a surface light source.

A step portion 154 is formed in the light incident portion of the light guide plate 1473, and a reflection sheet 1472 corresponding to the front end portion of the adjacent light guide plate and the light guide plate is placed thereon. That is, the adjacent light guide plates are overlapped with each other in the direction orthogonal to the light exit surface of the light guide plate. As described above, the thickness of the light guide plate 1473 is a shape in which the thickness gradually decreases from the light incident portion to the tip portion. However, in order to make it easy to place the tip portion on the step portion 154 of the adjacent light guide plate, The thickness is constant.
In this embodiment, a side view type LED (side light emitting type) that emits light in a direction parallel to the electrode surface is used as the LED 151, but a top view that emits light in a direction orthogonal to the electrode surface is used. A type of LED may be used.

Returning to FIG. 3 and FIG. Conventionally, an LED substrate, a light guide plate, and a reflection sheet are attached to the front side (the back side in the figure) of the bottom frame 148, and the chassis is attached to the back side (the front side in the figure) of the bottom frame 148. It was common to attach a drive board. On the other hand, in this embodiment, the LED drive board 95 is attached to the back side of the bottom frame 148 as described above, and the LED board 1471, the light guide plate 1473, and the reflection sheet 1472 are attached to the front side of the heat spread 147. There is one feature. The heat spread 147 is formed by sheet metal processing similarly to the bottom frame 148, and a space in which air is circulated is formed between the heat spread 147 and the bottom frame 148 as described later. That is, the back side of the display panel module 14 of this embodiment has a double sheet metal structure. Thereby, as described below, it is possible to reduce the thermal interference between the components, further improve the dustproof property, and obtain the effect of increasing the rigidity. Each element shown in FIG. 3 will be described. Among the components attached to the heat spread 147, the light guide plate is located on the most front side. The reflex mold 146 regulates the height of the diffusion plate / optical sheet with respect to the light guide plate, and also has a function of returning light leaked in the lateral direction between the light guide plate / diffusion plate to the diffusion plate.
The light emitted from the light guide plate 1473 is incident on the diffusion plate 145, and the uniformity of luminance in the surface direction is improved. Next, the light is incident on an optical sheet 144 including, for example, a prism sheet (for example, three stacked), and the traveling direction is aligned with the front direction, and then incident on the liquid crystal panel cell 142. The liquid crystal panel cell 142 controls the amount of transmitted light according to the video signal for each pixel to be displayed. As a result, an image based on the input video signal is displayed on the video display device 1.
Note that the mold frame 143 of FIG. 3 positions and fixes the optical sheet 144 and the diffusion plate 145. The metal frame 141 positions and fixes the liquid crystal panel cell 142.

Next, the effect of reducing thermal interference between components in the present embodiment will be described with reference to FIG. The circuit elements attached to the bottom frame 148 include circuits with high heat generation, such as a power supply board 96, a signal board 91, and an LED drive board 95. For this reason, in the present embodiment, as will be described below, these circuit elements and the heat spread 147 having LEDs are arranged separately via a space.
FIG. 4 is a first cross-sectional view of the display panel module 14 according to an embodiment of the present invention, and is a cross-sectional view seen from the left when the display panel module 14 shown in FIG. 3 is assembled. In FIG. 4, the right side is the back side of the display panel module 14, and the left side is the front side. An LED substrate 1471, a reflection sheet 1472, and a light guide plate 1473 are fixed to the heat spread 147 by, for example, a pin mold 1474. The left end of the pin mold 1474 defines the position of the diffusion plate 145 by supporting the diffusion plate 145 from the back side.

  As described above, the light guide plate 1473 is superimposed on the adjacent light guide plate at the light incident part and the tip part. In this overlapping portion, the pin mold 1474 fixes the two light guide plates to each other. The LED included in the LED board 1471 is not shown because it overlaps with other components, but is disposed near the overlapping portion of the light guide plate, and the backlight generated by the LED mainly proceeds from the lower side to the upper side in the figure. To do.

Further, as described above, the circuit board having high heat generation such as the LED driving board 95, the signal board 91, and the power board 96 for driving the LEDs to light is placed on the back side (right side in the drawing) of the bottom frame 148 as described above. Installed.
In this embodiment, as shown in FIG. 4, a heat spread 147 in which LEDs are provided is arranged inside the bottom frame 148 on which various circuit boards are mounted as described above, that is, on the liquid crystal panel cell 142 side. By adopting a double sheet metal structure, a space of a predetermined size through which air can flow is provided, for example, as indicated by an elliptical mark with a broken line in the figure. In the case of a liquid crystal display device, an LED substrate 1471 on which an LED for irradiating light is mounted, an LED drive substrate 95, a power supply substrate 96, and a signal substrate 91, for example, as represented by a case where the luminance of an image to be displayed is high, There is a common problem that the timing with large power consumption is common, and there is a problem that thermal interference easily occurs.

  Therefore, in this embodiment, the LED board 1471, the LED drive board 95, the power supply board 96, and the signal board 91 are attached to the heat spread 147 and the bottom frame 148, respectively, and are separated from each other. A space of a predetermined size is provided between the spread 147 and the heat generated between the two heat generation sources (the LED (LED board 1471), the LED driving board 95, the power supply board 96, and the signal board 91). An effect of reducing interference can be obtained. Here, the size of the space between the bottom frame 148 and the heat spread 147, that is, the distance between the bottom frame 148 and the heat spread 147 is, for example, about 0.5 to 2 cm. Also, by providing air holes in the bottom frame 148 so that air outside the video display device can flow in this space, the LED (LED board 1471), the LED driving board 95, the power supply board 96, and the signal board 91 can be made better. Can be cooled.

Next, another embodiment of the present invention will be described with reference to FIG.
FIG. 5 is a rear view of a heat spread 147 in another embodiment of the present invention. Here, a case where the heat spread 147 is not a single component but is divided into, for example, three pieces 147a to 147c is shown as an example. One light guide plate assembly 150 shown in FIG. 10 is attached to each of the heat spreads 147a to 147c. Therefore, one of the heat spreads 147a to 147c has 24 areas (light guide plate blocks).

  As shown in FIG. 5, when the heat spreads divided into three are combined and integrated, the shape is determined so that the sheet metal of the heat spread overlaps at the joint, for example, there is a hole in the sheet metal Also try to block this. Thereby, the effect which improves the dustproof property of the display panel module 14 including the effect by the double sheet metal structure by the bottom frame 148 and the heat spread 147 can be acquired. Moreover, it becomes possible to perform thermal diffusion favorably by such a structure.

  Further, in FIG. 5, as shown by an ellipse as an example, for example, eight screwing portions for connecting adjacent heat spreads to each other are provided. That is, in each member of the heat spread 147 shown by 147a to 147c, for example, a projecting portion (claw) is formed at the lower end portion toward the front side of the figure, and a screwing hole is provided in this, so that the bottom frame 148 And tightening with mounting screws.

  FIG. 6 is a rear view of the display panel module 14 according to another embodiment of the present invention, and shows a fixing method between the bottom frame 148 and the heat spread 147 by screwing. Although many of the heat spreads 147 are not shown because they are rear views, as shown in FIG. 5 above, they are fastened together by screws, for example, in a portion surrounded by an ellipse.

FIG. 7 is a second cross-sectional view of the display panel module 14 according to another embodiment of the present invention. Among the eight screw-fixed portions in FIG. 6 is a cross-sectional view common to six locations near the center of the frame 148. FIG.
FIG. 8 is a third cross-sectional view of the display panel module 14 according to another embodiment of the present invention. Of the eight screwing portions in FIG. 6 is a cross-sectional view common to the two lowermost portions of the bottom frame 148. FIG.

As shown in FIG. 7, in the vicinity of the center portion of the bottom frame 148, the lower part of the heat spread 147 (for example, 147 a) protrudes to the back side and covers the back side of the bottom frame 148. Screwed. This makes it possible to improve the dust resistance as described above.
As shown in FIG. 8, at the lower part of the bottom frame 148, both are screwed by the mounting screws 32 with the bottom frame 148 covering the back side of the lower part of the heat spread 147 (147 c). This makes it possible to improve the dust resistance as described above. In FIG. 8, the heat spread 147 is bent toward the lower side at the contact portion with the bottom frame 148, but conversely, the heat spread 147 may be bent toward the upper side.

  By having the structure shown in FIG. 7 and FIG. 8, the effect of improving the rigidity of the display panel module 14 can be obtained. This is not only because the bottom frame 148 and the heat spread 147 are rigid, but because both form a box-shaped structure with a space of a predetermined size as described above. For example, compared with the case where the bottom frame 148 and the heat spread 147 are in contact with each other without being separated, or when the bottom frame 148 is thickened without providing the heat spread 147, the box-shaped structure in this embodiment is generally There is an effect that rigidity can be increased in the same amount of sheet metal material.

  The embodiments described so far are merely examples, and do not limit the present invention. For example, the structure of the image display device shown in FIG. 2, the structure of the display panel module shown in FIG. 3, the fixing method of each component shown in FIG. In addition to the structure of the screwing portion shown in FIG. 8, different embodiments can be conceived based on the gist of the present invention, all of which are within the scope of the present invention.

  1: Image display device, 14: Display panel module, 142: Liquid crystal panel cell, 147: Heat spread, 148: Bottom frame, 1471: LED substrate, 1473: Light guide plate, 150: Light guide plate assembly, 151: LED, 152: Hole 153: groove, 91: signal board, 92: HDD / removable HDD, 93: area control board, 94: T-CON board, 95: LED drive board, 96: power board, 31, 32: mounting screws.

Claims (4)

A video display device having a display panel module for displaying video,
The display panel module is
A light source for supplying light to a display panel included in the panel module;
A light source substrate to which the light source is attached;
A holding member to which the light source substrate is attached;
The holding member is attached and has a metal bottom frame disposed on the back side of the display panel module,
On the back side of the bottom frame, a light source driving board for driving a light source, a power supply board and a signal board are provided,
An image display device, wherein a space is formed between the holding member and the bottom frame. The video display device according to claim 1,
A display panel liquid crystal panel cell included in the panel module;
A backlight device for irradiating light to the liquid crystal panel cell by the holding member, the light source, a light guide plate for guiding light from the light source toward the liquid crystal panel cell, and a reflection sheet provided on the back side of the light guide plate A video display device characterized by comprising: The video display device according to claim 1,
The image display apparatus, wherein the holding member has a member divided into a plurality of parts, and the members are connected to each other to form the holding member. The video display device according to claim 1,
The image display apparatus according to claim 1, wherein the holding member has a member divided into a plurality of parts, and has a protruding portion for attaching a fixing member to be fastened together with the bottom frame at an end of the member.

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