JP2007328281A - Display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure for efficiently dissipating heat generated from a back-light source in a display apparatus having a thin type case. <P>SOLUTION: This invention discloses the display apparatus (0200) comprising: the thin type case (0210); a metal chassis (0220) which is arranged inside the thin type case and functions as a structure member; and a display board (0230) arranged on one face of the metal chassis, and comprising a lengthy rectangular light source unit (0240) arranged closely to the metal chassis. Thus, since the heat generated from the light source unit can be efficiently dissipated by the metal chassis, rise in temperature of the light source unit can be suppressed, and an efficiency and a lifetime of light emission can be extended. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display device having a structure for efficiently radiating heat generated from a backlight light source.

Conventionally, a backlight of a display device irradiates the display panel with light emitted from a light source disposed on the back or side of the liquid crystal display panel. In such a display device, the light source becomes hot when driven, and the temperature rise of peripheral electronic components also overlaps, which may cause malfunction of the light source and reduce the light emission efficiency and the light emission lifetime. Further, in recent thin display devices, since the depth of the device main body is small, a gap between substrates mounted with a backlight and electronic components installed on the back surface of the liquid crystal display panel is also small. Therefore, the flow of the airflow for radiating the heat generated from each electronic component to the outside of the device is slow, and the heat tends to be trapped inside. For this reason, it is necessary to efficiently dissipate the heat generated from the light source and other electronic components to the outside and suppress the temperature rise inside the apparatus main body. For example, in the display device described in Patent Document 1, a heat sink having a plurality of fins and a heat dissipation hole for heat dissipation are provided in the housing, and a heat dissipation hole is provided between the top plate portion of the frame and the upper surface portion of the housing. A structure in which a gap is formed is disclosed. Thereby, the heat from the light source can be efficiently released outside the display device.
JP 2006-106272 A

  However, the display device described in Patent Document 1 requires a plurality of structures for heat dissipation, and further requires a certain space in the display device in order to form a gap for heat dissipation. There was a problem that it was difficult to make it.

  In order to solve the above problems, (1) the present invention is a thin casing, a metal chassis that functions as a structural member disposed inside the thin casing, and a display board that is disposed on one surface of the metal chassis. The display device includes a long strip-shaped light source unit arranged along one side of the display plate and close to the metal chassis. (2) In the present invention, the metal chassis has a plate shape that has substantially the same outer shape as the main surface of the thin casing, covers the entire main surface, and functions as a heat radiating fin of the light source unit. A display device is provided. Moreover, (3) this invention provides the display apparatus with which the said light source unit is affixed with the adhesive tape with respect to a metal chassis, and is arrange | positioned. (4) The present invention provides a display device further comprising a pressing holder for pressing the light source unit against the metal chassis. In addition, (5) the present invention provides a display device that further includes a drive circuit unit that is connected to the display board and is folded from the end of the display board to the back side of the metal chassis. In addition, (6) the present invention provides a display device that further includes a flexible circuit unit that is connected to the light source unit and is folded from the opening provided in a part of the metal chassis to the back side of the metal chassis. In addition, (7) the present invention provides a display device in which the metal chassis has a side wall for increasing the torsional rigidity of the metal chassis at all or part of its periphery. (8) The present invention provides the display device, wherein the thin casing has a size in a range of 20 cm to 35 cm x 2 cm in length x width x height. Furthermore, (9) the present invention provides a display device in which the display plate has a bezel surrounding four sides of the display structure glass, and the bezel is thermally connected to the metal chassis.

  In the display device of the present invention, since the light source unit is disposed close to the metal chassis, the heat generated from the light source unit is transmitted to the metal chassis and can be efficiently dissipated. Thereby, the temperature rise of the light source unit can be suppressed without providing a special member for heat dissipation, and the light emission efficiency and the light emission life can be extended. Further, the light source unit can be fixed by having the pressing holder. Furthermore, by having the bezel, the heat generated from the light source can be efficiently radiated by the metal chassis and the bezel.

  In addition, by arranging the drive circuit unit and the flexible circuit unit on the surface opposite to the surface on which the light source unit is arranged with respect to the metal chassis, the drive circuit unit and the flexible circuit unit for heat generated from the light source unit are obtained. Can be prevented.

  Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to these embodiments, and can be implemented in various modes without departing from the gist thereof. The first embodiment relates to claims 1 to 3, 7, and 8. The second embodiment relates to claims 4 and 9. The third embodiment relates to claims 5 and 6.

<< Embodiment 1 >>
<Outline of Embodiment 1>
By making the casing thinner than the conventional display device, it becomes difficult to separately arrange a member or the like for releasing the heat generated from the backlight. The present embodiment relates to a display device using a metal chassis that is a structural member in order to efficiently dissipate heat from a light source for backlight.

<Configuration of Embodiment 1>
FIG. 1 is an overall view of a flat display device of the present invention, and FIG. 2 is an exploded perspective view of only a configuration necessary for this embodiment. The “display device” (0100, 0200) of this embodiment includes a “thin housing” (0110, 0210), a “metal chassis” (0220), a “display board” (0230), and a “light source unit” ( 0240).

  The “display device” (0100, 0200) of the present invention refers to a display device having a display that requires a backlight because the present invention is an invention for efficiently dissipating heat generated from the backlight. . As the backlight light source, for example, an LED, a fluorescent tube, a fluorescent display tube, or the like can be used. As the display, a liquid crystal display is preferable in order to make the display device thin.

  “Thin housing” (0110, 0210) refers to a thin box for housing electronic components inside. Electronic components refer to internal components such as necessary speakers and terminals in addition to a substrate, a display board, a battery, and the like for performing a function as a display device. The “thin” means that the height (thickness) of the display device is smaller than the length and width of the display surface of the display device. As shown in FIG. 1, when the length, width, and height (thickness) lengths are X, Y, and W, for example, W is about 1/20 to 1/10 for X and Y, for example. Can be said to be thin. For example, a display device in which X × Y × W of a thin casing has a size in the range of 20 cm to 35 cm to 2 cm corresponds to the display device of the present invention.

  Next, an example of a metal chassis is shown in FIG. The “metal chassis” (0320) is disposed inside the thin casing (0310) and functions as a structural member. The “structural member” is a member arranged for the purpose of preventing deformation or destruction of all or part of the electronic device due to external force. In many conventional display devices, since the casing functions as a structural member, it is necessary to give the casing mechanical strength, and there is a limit to reducing the thickness and weight of the device. On the other hand, by using a metal chassis disposed inside the housing as a structural member, it is possible to further reduce the thickness and weight.

  Further, as shown in FIG. 3 (2), the metal chassis has substantially the same outer shape as the main surface of the thin casing (0310), and has a flat plate shape covering substantially the entire main surface. Is preferred. The “main surface of the thin casing” refers to a surface that forms the front surface of the display device. By adopting such a shape, the mechanical strength of the entire display device can be increased, and the display device can be made thinner and lighter. In addition, by disposing electronic components such as a substrate on both surfaces of the planar portion of the metal chassis, the housing does not need to support the electronic components. Furthermore, the metal chassis can function as a heat radiation fin of the light source unit by forming the metal chassis so as to cover substantially the entire main surface of such a thin casing. “Heat radiation fin” refers to a shape having a large surface area in order to increase heat radiation efficiency. As shown in FIG. 3A, the metal chassis has a flat plate shape as a whole. However, since the light guide unit is disposed close to the metal chassis as will be described later, the heat is radiated from the entire metal chassis. In that respect, it can be said that the metal chassis functions as a radiating fin as a whole. 4 shows the XX ′ cross section of FIG. 3, the rib (0421) may be provided on the metal chassis (0420) in this way to function as a radiation fin. The rib also has an effect of increasing the rigidity of the metal chassis.

  Furthermore, as shown in FIG. 5, the metal chassis may have a side wall (0521) for increasing the torsional rigidity of the metal chassis at all or part of the periphery thereof. In FIG. 4, the portion including the rib (0421) of 0422 corresponds to the side wall. Thus, when the metal chassis has high torsional rigidity, it is possible to suppress the influence of external force on the display plate and the light guide unit disposed on the front surface thereof. Further, as described above, the side wall can also function as a heat radiating fin.

  The material of the metal chassis is not particularly limited as long as it is a metal having rigidity capable of holding a certain shape. Preferably, it is made of a lightweight alloy containing at least one of aluminum, titanium, and magnesium. Since these materials have a small specific gravity, the weight of the metal chassis can be reduced. Further, since the heat conductivity is high, not only the heat generated by the light source unit but also the heat generated inside the display device can be efficiently diffused.

  The “display board” (0230) is arranged so as to overlap with one surface of the metal chassis (0220), that is, the flat portion of the metal chassis. The display plate is a member necessary for performing a display function including a liquid crystal unit and a light guide unit. Specifically, the liquid crystal unit includes a liquid crystal panel, a polarizing plate, a color filter, a diffusion film, and the like, and the light guide unit includes a light guide plate, a reflection plate, and other necessary members. It is not limited to.

  The “light source unit” (0240) is configured to have a long strip-like structure arranged along one side of the display plate and close to the metal chassis. FIG. 6 shows an example of the light source unit. The light source unit includes a light source (0641) for a backlight, a substrate (0642), and the like. As the light source, as described above, an LED, a fluorescent tube, a fluorescent display tube, or the like can be used. In the figure, as an example, a case where a plurality of white LEDs serving as light sources are mounted in the longitudinal direction of the substrate (0642) is shown. FIG. 7 is a diagram showing (1) a state in which a light source unit is arranged on a metal chassis, and (2) a state in which a display plate is further arranged. Thus, when the light source is an LED, the substrate has a long strip-like structure, and the light source arranged on the substrate is arranged along one side of the light guide plate in the display plate. ing. When the light source is a fluorescent tube, the fluorescent tube itself has a long strip-like structure. By arranging the light source unit in this way, light from the light source can be evenly transmitted to the liquid crystal panel or the like through the light guide plate.

  The light source unit is disposed close to the metal chassis. “Adjacent to” means that it is not always necessary to make contact with each other, and the distance between the light source unit and the metal chassis is such that heat from the light source unit can be transferred to the metal chassis. FIG. 8 shows an arrangement example of a light source unit (0840) composed of a light source (0841) and a substrate (0842) and a metal chassis (0820) in the YY ′ cross section of FIG. 7 (2). For example, the whole light source unit may be in contact with the metal chassis as in (1), or the light source unit may have a portion that is not in contact with the metal chassis as in (2). In (1) and (2), the substrate (0842) surface of the light source unit is close to the metal chassis. However, as shown in (3), the light source (0841) side is close to the metal chassis. Good. Further, as in (4), when the light source surface is brought close to the metal chassis, a heat radiation sheet or the like (0843) may be inserted into the gap with the metal chassis to increase the heat radiation efficiency. However, as will be described later in the examples, it is preferable to bring the substrate surface closer to the metal chassis than the case where the light source side is closer to the metal chassis, because the heat radiation efficiency is better. Further, the light source unit may be arranged on the metal chassis by any method. For example, it may be fixed with screws or the like, or may be fixed by forming a recess or a rib for inserting the light source unit on the metal chassis. Furthermore, fixing with an adhesive tape may be used. In this case, it is preferable that the pressure-sensitive adhesive tape has heat resistance and charge resistance and hardly deteriorates.

<Effect of Embodiment 1>
Since the light source unit is arranged close to the metal chassis in the display device of this embodiment, the heat generated from the light source unit is transmitted to the metal chassis and can be efficiently dissipated. Thereby, the temperature rise of a light source unit can be suppressed and the fall of luminous efficiency and the reduction | decrease of a light emission lifetime can be suppressed.

<< Embodiment 2 >>
<Outline of Embodiment 2>
The display device of this embodiment is characterized by having a pressing holder and a bezel. Thereby, while being able to fix a light source unit, the heat which generate | occur | produced from the light source can be efficiently thermally radiated with a metal chassis and a bezel.

<Configuration of Embodiment 2>
FIG. 9 shows the configuration of this embodiment. The “display device” (0900) of the present embodiment is based on the first embodiment, and includes a “thin housing” (0910), a “metal chassis” (0920), a “display board” (0930), and a “light source”. “Unit” (0940), “Pressing Holder” (0950), and the display board have “Bezel” (0960).

  The “pressing holder” (0950) is configured to press the light source unit (0940) against the metal chassis (0920). FIG. 10 shows an example of the pressing holder. In FIG. 10, the pressing holder (1050) has a frame shape, but is not limited to this shape. For example, it may have a strip shape that is substantially the same as the light source unit that covers only the upper part of the light source unit. FIG. 11 shows an example of the YY ′ cross section of FIG. 7B in a state where the pressing holder and the bezel are arranged. As shown in FIG. 11 (1), the light source unit (1140) can be fixed by being sandwiched between the metal chassis (1120) and the pressing holder (1150). As shown in FIG. 11 (2), the metal chassis and the pressing holder may be fixed by a hook-like structure (1151). In addition, the pressing holder can be used for positioning and fixing the liquid crystal unit (1131) and the light guide unit (1132) of the display plate (1130) by adopting a shape like 1152. The pressing holder can be made of various materials such as plastic and urethane, but it must have heat resistance and buffering characteristics in order to be placed on top of the light source unit and to protect and fix the display board. preferable.

  The “bezel” (0960) is disposed so as to surround the four sides of the display structure glass of the display board (0930), and is thermally connected to the metal chassis (0920). FIG. 12 shows an example of a bezel. “Display structure glass” refers to, for example, the liquid crystal panel of the liquid crystal unit (1131) shown in FIG. The bezel (1160) protects and fixes the display plate by being disposed so as to surround the four sides of the liquid crystal glass. By fixing the bezel and the metal chassis with screws or the like, the display board can be sandwiched and fixed. Further, “thermally connecting” means arranging the metal chassis so as to receive heat. In other words, the bezel is further received from the metal chassis that has received the heat generated from the light source by being placed in contact with or close to the metal chassis. Thereby, the heat from the light source can be radiated more efficiently than in the case of only the metal chassis. Therefore, it is desirable to use a material with good thermal conductivity for the bezel. For example, it may be made of metal similar to the metal chassis, or may be made of non-metal such as fiber reinforced plastic.

<Effect of Embodiment 2>
According to the display device of this embodiment, the light source unit can be fixed by the pressing holder, and the heat generated from the light source can be efficiently radiated by the metal chassis and the bezel.

<< Embodiment 3 >>
<Outline of Embodiment 3>
The display device of this embodiment is characterized in that the drive circuit unit and the flexible circuit unit are arranged on the opposite surface of the light source unit with respect to the metal chassis. With such a structure, it is possible to prevent heat generated from the light source unit from being transmitted to the drive circuit unit or the like.

<Configuration of Embodiment 3>
FIG. 13 shows a part of the configuration of this embodiment. The “display device” of the present embodiment is based on the first embodiment, and includes a “thin housing” (not shown), a “metal chassis” (1320), a “display board” (not shown), “ It has a “light source unit” (not shown), and further includes a “drive circuit unit” (1370) and a “flexible circuit unit” (1380).

  FIG. 13 is a front view of an example of a state in which a light source unit is arranged on a metal chassis, and FIG. 14 is a rear view.

  The “drive circuit units” (1370, 1470) are connected to the display board (1330) and are folded from the end of the display board to the back side of the metal chassis (1320, 1420). As shown in FIG. 13, the drive circuit unit is a unit having a circuit for driving the display, and includes a circuit board (1371) and a flexible circuit board (1372) for connecting the circuit board and the display board. The display plate end and the flexible circuit board are connected. By folding the flexible circuit board portion, the circuit board can be disposed on the back surface of the metal chassis as shown in FIG. The ZZ ′ cross section of FIG. 14 is shown in FIG. FIG. 15 shows a state in which a pressing holder and a bezel that are not shown in FIG. 13 are also arranged. As shown in FIG. 15 (1), the flexible circuit board (1572) connected to one end of the display board (1530) is folded to the back surface so as to wind the metal chassis (1520).

  The “flexible circuit unit” (1380, 1480) is connected to the light source unit (1340, 1440) and is folded from the opening provided in a part of the metal chassis (1320, 1420) to the back side of the metal chassis. Be placed. As shown in FIG. 14, the flexible circuit unit is disposed on the back surface of the metal chassis (1420), and connects the light source unit (1440) and the circuit board (1471) for controlling the backlight. The flexible circuit unit and the light source unit are connected through an opening (0321) provided in a part of the metal chassis shown in FIG. In FIG. 13, an opening is provided in a portion surrounded by a dotted line. The substrate of the light source unit has a connection terminal with the flexible circuit unit at a position overlapping the opening of the metal chassis, and can be connected to the terminal of the flexible circuit unit derived from the back surface of the opening. A sectional view of the opening portion is shown in FIG. As shown in FIG. 15 (2), the flexible circuit unit connected to the light source unit (1540) disposed on the metal chassis (1520) passes through the opening of the metal chassis (1520) to the back surface of the metal chassis. It is induced.

<Effect of Embodiment 3>
In the display device of the present embodiment, the drive circuit unit and the flexible circuit unit are disposed on the surface opposite to the surface on which the light source unit is disposed on the metal chassis surface. Thereby, the heat generated from the light source unit is not easily transmitted to the drive circuit unit and the flexible circuit unit.

  The relationship between the arrangement position of the light source unit and the metal chassis and the heat radiation efficiency was examined using a device with a simplified configuration of the display device of the present invention. At that time, an experiment was conducted using a white LED chip manufactured by Nichia Corporation and a metal chassis made of a magnesium alloy.

<Configuration>
The configuration of the example is shown in FIG. In (1), the substrate (1603) surface of the light source unit is placed close to the metal chassis (1604). The metal chassis, the substrate, and the light guide plate (1605) are bonded to each other with a Kapton (registered trademark) tape (1606). In addition, a white reflective film (1607) is disposed on the opposite side of the substrate surface of the LED chip (1602), and the upper part of the light guide unit is covered with the bezel (1601). In (2), the LED (1602) surface of the light source unit is placed close to the metal chassis (1604). A heat-dissipating sheet (1608) manufactured by Kitagawa Industries is arranged between the LED chip and the metal chassis, and the heat-dissipating sheet, the light guide plate, and the metal chassis are bonded together with Kapton tape (1606), as in (1). Yes. The upper part of the light source unit is covered with a bezel (1601).

  With respect to the apparatus having the light source unit arrangement position as described above, a current of 17 mA was passed per LED chip, and the temperature rise of the LED upper surface when the dimming rate was changed was measured.

<Result>
The result of the temperature rise is shown in FIG. As shown in the figure, it can be seen that at any dimming rate, when the substrate surface of the light source unit is close to the metal chassis (1), the temperature rise is less and the heat dissipation effect is higher. In particular, when the light control rate was 100%, a difference of about 4 ° C. was observed.

<Discussion>
From the experimental results, it can be said that the heat generated by the LED can be efficiently transmitted to the metal chassis by arranging the substrate surface of the light source unit close to the metal chassis.

An example of the display device of the present invention 1 is an exploded perspective view illustrating an example of a display device according to Embodiment 1. FIG. Diagram showing an example of a metal chassis Diagram explaining heat dissipation fins The figure explaining the side wall of a metal chassis The figure which shows an example of a light source unit The figure which shows the positional relationship of a metal chassis, a light source unit, and a display board. Sectional drawing which shows the positional relationship of a metal chassis, a light source unit, and a display board FIG. 6 is an exploded perspective view illustrating an example of a display device according to a second embodiment. Diagram showing an example of a pressing holder Sectional drawing which shows the positional relationship of a pressing holder and a bezel Figure showing an example of a bezel Surface view of metal chassis with drive circuit unit and flexible circuit unit Rear view of metal chassis with drive circuit unit and flexible circuit unit Cross-sectional view of drive circuit unit and flexible circuit unit The figure which shows the structure of an Example The figure which shows the temperature rise result of an Example

Explanation of symbols

0200 Display device 0210 Thin housing 0220 Metal chassis 0230 Display board 0240 Light source unit 1150 Pressing holder 1160 Bezel

Claims (9)

A display device comprising a thin housing, a metal chassis that functions as a structural member disposed inside the thin housing, and a display plate disposed on one surface of the metal chassis,
A display device comprising a long strip-like light source unit disposed along one side of a display plate and in proximity to the metal chassis.   2. The display according to claim 1, wherein the metal chassis has a substantially same outer shape as a main surface of the thin casing, and is a flat plate functioning as a heat radiation fin of the light source unit by covering substantially the entire main surface. apparatus.   The display device according to claim 1, wherein the light source unit is disposed by being attached to the metal chassis with an adhesive tape.   The display device according to claim 1, further comprising a pressing holder for pressing the light source unit against the metal chassis.   5. The display device according to claim 1, further comprising a drive circuit unit that is connected to the display board and is folded from an end portion of the display board to the rear surface side of the metal chassis.   The display device according to claim 1, further comprising a flexible circuit unit that is connected to the light source unit and is folded from an opening provided in a part of the metal chassis to a metal chassis rear surface side. .   The display device according to claim 1, wherein the metal chassis has a side wall for increasing torsional rigidity of the metal chassis at all or part of the periphery of the metal chassis.   8. The display device according to claim 1, wherein the thin casing has a size in a range of 20 cm to 35 cm and 2 cm in height × width × height.   The display device according to claim 1, wherein the display board includes a bezel surrounding four sides of the display structure glass, and the bezel is thermally connected to the metal chassis.