JP4909808B2 - Flat display device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a flat display device such as a plasma display device, and more particularly to a flat display device having a chassis structure suitable for cooling heat generated by a display panel and a method for manufacturing the flat display device.

  In recent years, the demand for information display devices has greatly shifted to large-screen flat display devices due to the shift to digital terrestrial broadcasting. One of the flat display devices is a plasma display device. In the plasma display device, elements to be discharged are arranged in a cell shape, and two glass substrates are bonded together and sealed, and the discharge elements are discharged in a sealed space, and the phosphor on the glass substrate emits light to generate an image. The plasma display panel (hereinafter referred to as PDP) generates heat during this discharge. The temperature rise due to the heat generation of the PDP not only deteriorates the image quality because it changes the light emission luminance of the phosphor, but also may cause damage to the glass substrate due to local temperature distribution of the glass substrate. For this reason, the heat generated in the PDP is transferred to a metal chassis member having good thermal conductivity through an adhesive high thermal conductive sheet or the like and radiated into the air. The chassis member is fixed on the back side of the glass substrate of the PDP by an adhesive high thermal conductive sheet or the like, but not only the heat dissipation of the PDP but also the strength of the PDP and the circuit board that drives and operates the PDP. It plays a role as a member to be held on the plane side opposite to the fixing plane side.

  The following technique is disclosed with respect to the problem of the temperature rise in a plasma display apparatus. The plasma display device described in Patent Literature 1 reduces the temperature unevenness in the surface of the PDP and suppresses the adverse effect on the characteristics of the displayed image and the lifetime of the image display device. A frame chassis is provided that supports the circuit board on the back side with a space between the thermally conductive sheet provided so as to be in close contact with the back side.

  The plasma display device described in Patent Document 2 improves the coupling structure of the PDP and the chassis base with respect to the heat conducting member so that the thermally deformed PDP can be uniformly adhered to the heat conducting member. In addition, in the first adhesive layer for fixing the PDP and the heat conducting member, and the second adhesive layer for fixing the heat conducting member and the chassis base, the binding force of the first adhesive layer is the binding force of the second adhesive layer. It has a larger structure.

JP 2006-39072 A JP 2006-119593 A

  In the plasma display device, the heat generated by the PDP during discharge has a temperature distribution depending on the relationship between the content of the displayed image, the arrangement position of the discharge elements, and the like, which is a problem for efficient cooling.

  FIG. 3 is a diagram illustrating a heat transfer state of a chassis member in a conventional flat display device. FIG. 3A shows a heat generation state in the chassis member, and the heat generation from the PDP 3 tends to be in a high temperature state at a substantially central portion. In other words, as indicated by the contour lines of the ellipse, the distribution is such that the central part is a high temperature part a and the peripheral part is a low temperature part e. Heat generated from the PDP 3 is transferred to the chassis member 5 through the high thermal conductive adhesive member 4. In the chassis member 5, as indicated by an arrow 100, the heat diffuses radially and tries to have a uniform temperature distribution over the entire area. FIG. 3B shows the heat dissipation state of the chassis member, and the heat diffused in the chassis member 5 is transferred by the cooling air 200 passing through the chassis surface from the lower part to the upper part to be dissipated. At that time, the air that has conducted heat transfer from the chassis member in the lower part approaches the saturated state of heat transfer in the upper part, and the heat transfer thermal efficiency decreases. As a result, the temperature distribution of the chassis member after heat dissipation is the temperature distribution of the high temperature part a at the upper end and the low temperature part e at the lower end. This tendency is conspicuous due to an increase in the amount of heat generated with an increase in the size, brightness, and definition of the PDP, and the occurrence of such a temperature distribution deteriorates the efficiency of the heat dissipation operation and increases the reliability of the PDP. There is a risk of damage.

  Furthermore, the absolute temperature rise of the enlarged chassis member increases the difference in strain between the two members due to the difference in thermal expansion coefficient between the PDP and the chassis member. This means that the chassis member joined to reinforce the PDP strongly applies stress to the PDP due to the displacement of thermal expansion, which causes deterioration in performance and damage to the discharge element. .

  In Patent Documents 1 and 2, no consideration is given to the heat generation distribution in the PDP and the temperature distribution generated by the cooling air flow. Further, Patent Documents 1 and 2 have the following problems.

  The plasma display device described in Patent Document 1 has the merit of avoiding the influence of heat generated by circuit components on the PDP because the chassis member and the PDP are arranged apart from each other. However, in order to dissipate the heat generated by the PDP from the heat conductive sheet and cool it, the heat conductive sheet needs to have heat transfer performance superior to that of the conventional frame chassis, and the cost is increased by providing an expensive heat conductive sheet. Become.

  The plasma display device described in Patent Document 2 dissipates heat generated from the PDP by fixing and maintaining the heat conducting member on the PDP side by the bonding force of the first adhesive layer, regardless of the deformation of the PDP that is a heating element. I will try to let you. However, the heat transfer to the chassis base is impaired by the second adhesive layer being separated from the chassis base. There is no problem when the heat dissipation performance of the heat conducting member is superior to the heat dissipation performance of the chassis base. However, in order to obtain this heat dissipation performance, the cost becomes high as in Patent Document 1. Furthermore, if the heat dissipation of the chassis base is not expected, the second adhesive layer can be omitted.

  An object of the present invention is to provide a flat display device that realizes efficient cooling with a simple structure against heat generation of a display panel.

  In order to solve the above-described problems, the present invention provides a flat panel display device that dissipates heat generated by a display panel by a chassis member. The chassis member is divided into a plurality of chassis pieces in the vertical direction and has high thermal conductivity. It is a structure that is fixed by an adhesive member, receives heat generated by the display panel, diffuses heat in each chassis piece, and dissipates heat in the ventilated air. At that time, heat generated from the high temperature portion of the display panel is received by the chassis piece arranged on the lower side among the plurality of chassis pieces, and the temperature state after thermal diffusion in each chassis piece is arranged on the lower side. The chassis piece was configured to be hotter than the chassis piece placed on the upper side.

  Further, the present invention provides a method for manufacturing a flat display device in which heat generated by a display panel is dissipated by a chassis member. The chassis member is divided into a plurality of chassis pieces according to the size of the display panel, and the It arrange | positions so that heat_generation | fever receives heat with the chassis piece located in the lower side, and each chassis piece is fixed to a display panel with the adhesive member of high heat conductivity. In the case of flat display devices having different display panel sizes, at least some of the chassis pieces have a common shape with respect to the chassis pieces used in these devices.

  According to the present invention, efficient cooling can be realized with a simple structure against heat generation of the display panel, and there is an effect of improving the performance and reliability of the flat display device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram conceptually showing the configuration of an embodiment of a flat display device according to the present invention. (A) is a front view, (b) is a side view, and a part of components such as a display panel (PDP) is shown in a transparent manner for convenience of explanation. The flat display device 1 includes a self-luminous display panel (PDP) 3 inside a housing 2. The display panel 3 has a configuration in which the discharge cell layer is sandwiched between a front glass substrate and a back glass substrate. A chassis member 5 is fixed to the rear glass substrate side of the display panel 3 by an adhesive member 4 such as a high thermal conductivity double-sided adhesive tape or adhesive. Further, a plurality of circuit boards 7 are mounted on the rear side of the chassis member 5 by a support member 6, and circuit parts for driving the display panel 3 and circuit parts for operating the flat display device 1 are mounted on the circuit board 7. Place.

  Here, the chassis member 5 is a metal material such as aluminum having good conductivity, receives heat generated from the display panel 3, dissipates heat in the member, and dissipates it into the air. In that case, it is set as the structure radiated with the cooling wind which goes upwards from the downward direction as natural convection. The circuit board 7 has a plurality of connectors 8 for electrical connection with the display panel 3. The plurality of connectors 8 and the electrodes drawn from the display panel 3 are electrically connected by a plurality of flexible printed wiring boards 9.

  Here, the structure of the chassis member 5 in a present Example is demonstrated in detail. The chassis member 5 is fixed to the entire surface of the display panel 3 in a substantially equal plane in a state of being divided into a plurality. In FIG. 1, it is divided into three chassis members (chassis pieces) 51, 52, 53. Their shapes are substantially equal to the horizontal direction (X direction) of the display panel 3 and are divided into three in the vertical direction (Y direction) of the display panel 3. However, the shape of each chassis piece is not a simple rectangular shape, but is divided into building blocks including a combination of a convex shape and a concave shape (or H shape). That is, the lower chassis piece 51 has a substantially convex shape including the central portion of the display panel, and the middle chassis piece 52 has a substantially H shape so as to avoid the central portion of the display panel. The upper chassis piece 53 has a substantially reverse convex shape toward the center of the display panel. The shapes of these chassis pieces are determined based on the heat distribution of the display panel and the direction of the cooling air, as will be described later, and the number of divisions of the chassis member 5 is not limited to three divisions. .

  FIG. 2 is a diagram for explaining the cooling operation of the flat display device of FIG. (A) is a front view, (b) is a side view, and the chassis member 5 and the display panel 3 are taken out and shown. The heat generation state of the display panel 3 generally has a tendency that the central portion becomes the high temperature portion a and the peripheral portion becomes the low temperature portion e as indicated by the elliptic contour lines.

  The chassis member 5 of the present embodiment is divided into three chassis pieces 51, 52, 53 as shown in FIG. Heat generated from the discharge elements of the display panel 3 is received by the chassis pieces 51, 52, 53 via the heat conductive adhesive member 4. And although it diffuses in each chassis piece 51,52,53, since the spreading | diffusion direction is controlled by a division | segmentation shape, the temperature rise of each chassis piece 5 differs depending on a division | segmentation shape.

  Here, heat transfer in the divided chassis member 5 will be described. First, the heat of the high temperature part a generated in the central part of the display panel 3 is received by the lower chassis piece 51 facing the high temperature part a, and reaches the lower low temperature part e as indicated by the arrow 101 inside the chassis piece 51. Thermal diffusion toward. This is because the heat transfer path is separated from the middle chassis piece 52, and heat conduction cannot be performed upward and heat diffusion cannot be performed. As a result, the chassis piece 51 reaches the temperature T1. On the other hand, in the middle-stage chassis piece 52, the heat of the intermediate temperature portion b is transferred to receive the heat, and as indicated by an arrow 102, it is thermally diffused by heat conduction in the lateral direction to reach the temperature T2. Further, in the upper chassis piece 53, the heat of the intermediate temperature portion c is transferred and received, and as indicated by an arrow 103, the heat is diffused upward by heat conduction to reach a temperature T3. As a result of different maximum temperatures of the heat sources in the respective chassis pieces 51, 52, 53, the temperature states after thermal diffusion in the respective chassis pieces 51, 52, 53 are different, and the relationship of T1> T2> T3 is established.

  Next, the heat radiation operation by the natural convection of air to the chassis member 5 will be described. As shown in FIG. 3, in the conventional continuous structure of the chassis member 5, heat from the display panel is diffused over the entire plane, and the temperature is almost uniform over the entire surface of the chassis member. The air heated by the heat transfer from the chassis member to the air naturally convects from below to above. The velocity boundary layer capable of transferring predetermined heat in the air is thin on the lower end side and has a high heat transfer efficiency, but becomes thicker on the upper end side, resulting in poor heat transfer efficiency. That is, since heat transfer to the air is saturated on the upper end side, heat dissipation on the upper end side of the chassis member is insufficient, and the high temperature portion remains.

  On the other hand, in this embodiment, as shown in FIG. 2, the chassis member 5 is divided in the direction of the ventilation 200 by natural convection. Then, by restricting the heat diffusion based on the division shape of the chassis piece, the temperature state of the chassis pieces 51, 52, 53 due to the heat generated from the display panel 3 is made higher at the lower end side (T1> T2> T3). ). In this way, a high temperature region (T1) is formed at the lower end of the chassis member, while the lower end has a thin air velocity boundary layer and high heat transfer efficiency. Heat can be dissipated. That is, it is possible to cool through the most efficient path for the heat generation of the high temperature portion a of the display panel 3.

  On the other hand, the air absorbed from the chassis piece 51 at the lower end naturally convects upward and continues to absorb heat from the chassis piece 52 and the chassis piece 53, but the heat transfer efficiency decreases toward the upper end side. . However, since the temperature state of the chassis piece 52 and the chassis piece 53 is lowered toward the upper end side (T3 <T2 <T1), the amount of heat radiation (heat transfer) required for cooling to a desired temperature may be small. Therefore, the high temperature portion does not remain at the upper end portion of the chassis member 3. As a result, the entire chassis member 5 can be efficiently cooled to a uniform temperature.

  Furthermore, since the chassis member 5 is divided, each chassis piece 51, 52, 53 has its own velocity boundary layer, and the velocity boundary of the upstream chassis piece 51 (52) in natural convection. The layer and the velocity boundary layer of the downstream chassis piece 52 (53) can be mixed to form a new velocity boundary layer. As a result, the heat transfer efficiency of the chassis piece 52 and the chassis piece 53 can be improved, and the cooling efficiency of the display panel 3 can be further improved.

  In the above embodiment, the case of heat dissipation by natural convection has been described. However, the present invention can be similarly applied to a case where air is forcibly ventilated by a cooling fan or the like. Also in that case, the division shape and the division form of the chassis member may be appropriately determined according to the heat generation state of the display panel 3 and the direction of the cooling air.

  Thus, according to the present embodiment, it is possible to provide a flat display device that realizes efficient cooling with a simple structure against heat generation of the display panel.

  Next, the mechanical strength effect by dividing the chassis member 5 will be described. As shown in FIG. 1, a plurality of circuit boards 7 are mounted on the chassis member 5, and each circuit board 7 is connected to an electrode of the display panel 3 by a flexible printed wiring board 9 via a connector 8. . The flexible printed wiring board 9 is attached so as to extend in the depth direction (Z direction) at the outer peripheral position of the display panel 3.

  As described above, when discharge display is performed on the display panel 3, the temperature of the chassis member 5 thermally connected by the heat generation rises. At this time, if there is a difference in thermal expansion between the display panel 3 and the chassis member, there is a problem that the display panel and the chassis member are warped (distorted) due to the bimetal phenomenon, and in an extreme case, the panel is damaged. Further, the warpage of the display panel and the chassis member causes a deformation of the connection position in the X direction or the Y direction with respect to the flexible printed wiring board 9, and there is a problem that the connector 8 is dropped or damaged. On the other hand, dividing the chassis member 5 as in this embodiment has an effect of alleviating these problems.

Here, the problem of the difference in thermal expansion between the display panel 3 and the chassis member 5 will be described. The thermal expansion coefficient of glass, which is a typical substrate material of the display panel 3, is about 8.5 × 10 ⁻⁶ / K, and the thermal expansion coefficient of aluminum, which is a typical material of the chassis member 5, is about 23.0. Since it is × 10 ⁻⁶ / K, both members have different elongation amounts due to temperature rise. As a result, the display panel 3 and the chassis member 5 are warped such that the display panel 3 side is concave. In addition, the set positions at both ends of the flexible printed wiring 9 joined to both members are displaced from the set positions at room temperature as warpage occurs. Here, since the flexible printed wiring board 9 is connected in a curved shape between the display panel 3 and the connector 8 on the circuit board 7, the extending direction of the connection of the flexible printed wiring board 9 (Z direction) ) Is not a problem because it can be absorbed by bending deformation. However, the displacement in the direction orthogonal to the connection direction (X direction or Y direction) cannot be absorbed by the curved deformation of the flexible printed wiring board 9, and the connector 8 may fall off or be damaged.

  However, by dividing the chassis member 5 into small pieces of chassis pieces as in this embodiment, the amount of warpage (distortion amount) can be reduced. Further, the displacement of the connection position of the flexible printed wiring 9 is reduced, and there is no problem that the connector falls off.

  As described above, according to the present embodiment, it is possible to reduce the deformation and distortion of the component parts caused by the difference in the thermal expansion coefficient between the display panel and the chassis member due to heat generation, thereby improving the reliability of the flat display device.

  Note that the divided chassis member 5 is disposed and fixed to the display panel 3 so that the chassis pieces 51, 52, 53 have a gap D at room temperature. Since the adhesive member 4 to be fixed has viscosity, each chassis piece expands in all directions as the temperature rises, and there is a possibility that an end of an adjacent chassis piece collides to cause an accident such as peeling. In order to avoid this, it is preferable that the gap D at room temperature is larger than the thermal expansion difference between the chassis member and the display panel. The gap D also depends on the size of the chassis piece. The smaller the chassis piece (the greater the number of divisions of the chassis member 5), the smaller the difference in thermal expansion. Therefore, the gap D can be reduced.

Next, a method for manufacturing a flat display device using the chassis member divided as in this embodiment will be described.
As the flat display device 1 increases in size, the chassis member 5 to which the display panel 3 is fixed increases in size. Increasing the size of the chassis member 5 causes an increase in cost, such as an increase in production equipment for the chassis member 5 and a decrease in workability during assembly. On the other hand, by dividing and configuring the chassis member 5 for a large screen, it is possible to cope with a small production facility.

  Increasing the number of divisions of the chassis member 5 is not a preferable direction from the viewpoint of component management and workability of fixing to the display panel 3. In this case, the divided chassis pieces 52, 52, 53 are temporarily joined by a holding member such as a holding tape while maintaining the positional relationship of fixing to the display panel 3, and are managed as a unit by managing them integrally. Workability can be improved.

The method of dividing the chassis member 5 can be easily handled while suppressing an increase in cost even when manufacturing a flat display device having a display panel 3 having a different size.
FIG. 4 is a diagram showing an example of a method of dividing the chassis member 5 corresponding to two flat display devices having different display panel 3 sizes. (A) is the case of the small display panel 3a, and the chassis member 5a is composed of divided chassis pieces 51a, 52a, 53a. On the other hand, (b) is a case of a large display panel 3b, and a part of the chassis member 5a used in the display panel 3a is used in common. That is, the chassis pieces 51b and 53b are the same as the chassis pieces 51a and 53a. The chassis pieces 52b and 54b are newly added to the chassis pieces 51b and 53a, and are combined in a building block manner. With this configuration, parts can be used in common for a plurality of flat display devices having different screen sizes to facilitate manufacture.

  As described above, according to this embodiment, it is possible to provide a method for manufacturing a large-screen flat display device with high productivity and reliability.

The figure which shows notionally the structure of one Example of the flat type display apparatus by this invention. The figure explaining cooling operation | movement of the flat type display apparatus of a present Example. The figure which shows the heat-transfer state of the chassis member in the conventional flat type display apparatus. The figure which shows the example of a division | segmentation of the chassis member in case the magnitude | size of a display panel differs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Flat panel display device 2 ... Housing 3 ... Display panel (PDP)
4 ... High thermal conductive adhesive member 5, 51, 52, 53 ... Chassis member (chassis piece)
6 ... support member 7 ... circuit board 8 ... connector 9 ... flexible printed wiring board.

Claims (5)

In a flat display device that dissipates heat generated by a display panel by a chassis member,
The chassis member is divided into a plurality of chassis pieces in the vertical direction and fixed to the display panel with a highly heat conductive adhesive member, receives heat generated by the display panel, and thermally diffuses in each chassis piece, It is a structure that dissipates heat in the air that is ventilated,
Heat generated from the high temperature portion of the display panel is received by a chassis piece arranged on the lower side among the plurality of chassis pieces, and the temperature state after thermal diffusion in each chassis piece is arranged on the lower side. A flat display device characterized in that the chassis piece is configured to be hotter than the chassis piece arranged on the upper side. The flat display device according to claim 1,
The shape of each chassis piece is divided into a blockwork shape including a combination of a substantially convex shape and a substantially concave shape, and is arranged with a predetermined gap at the boundary of each chassis piece. Display equipment. The flat display device according to claim 1 or 2,
A circuit board placed on the chassis member;
A flexible printed wiring board connected to the display panel from the circuit board;
The flat panel display device, wherein the chassis member is divided at least in a direction orthogonal to a connection extending direction of the flexible printed wiring board. In the manufacturing method of a flat display device that radiates heat of the display panel by the chassis member,
In accordance with the size of the display panel, the chassis member is divided into a plurality of chassis pieces,
Arranged to receive heat from the high temperature part of the display panel at the chassis piece located on the lower side,
Each chassis piece is fixed to the display panel with a highly heat conductive adhesive member,
In the case of flat display devices having different display panel sizes, at least some of the chassis pieces of the chassis pieces used in these devices have a common shape. In the manufacturing method of a flat display device that radiates heat of the display panel by the chassis member,
In accordance with the size of the display panel, the chassis member is divided into a plurality of chassis pieces,
Arranged to receive heat from the high temperature part of the display panel at the chassis piece located on the lower side,
Each chassis piece is fixed to the display panel with a highly heat conductive adhesive member,
A method of manufacturing a flat display device, wherein the divided chassis pieces are temporarily joined by a holding member while maintaining a fixed positional relationship, and are integrally fixed.

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