JP5046905B2 - Flat display device - Google Patents

Description

  The present invention relates to a flat display device, and relates to a technique for cooling the heat generation of a self-luminous display panel.

  Self-luminous flat panel displays include plasma display panels (PDPs) that have formed a large market, and in the future, commercialization of organic electroluminescent (EL) panels and LED display panels is expected. ing. Here, these self-luminous display panels generate heat in the light-emitting elements. Since this heat generation affects the life and performance of the light emitting element, it must be cooled.

  In order to cool the display panel, a PDP device generally includes a metal chassis member having excellent thermal conductivity on a glass substrate on the back side of the PDP. The local heat generation of the PDP is first transferred to the chassis member and thermally diffused on the chassis member to suppress temperature unevenness of the PDP. Further, the heat diffused on the chassis member is transferred to the air ventilated on the surface of the chassis member, and is dissipated to the atmosphere, thereby cooling the PDP. Here, the direct bonding state between the PDP and the chassis member is dispersed contact at the contact interface. Therefore, in order to avoid the contact state which forms the fine space | gap which becomes the heat conductive efficiency fall, the joining of both members is adhering, interposing a heat conductive sheet (heat conductive member) etc. However, the PDP device is in a situation where the size of the display panel is enlarged, and conversely, the fixing work of the large-area heat conductive sheet has become a problem of generating bubbles in the heat conductive sheet, Improvements in workability and cost in fixing the heat conductive sheet are desired.

  As a technique for avoiding this problem, Patent Document 1 discloses a technique in which a thermally conductive member containing an adhesive material is applied in a plurality of lines.

  In addition, as a bonding member between the PDP and the chassis member, a hot-melt adhesive having adhesiveness filled with a thermal conductivity imparting agent is used, and this is discretely arranged in a predetermined direction to reduce the cost of the adhesive. A technique for reducing the amount is disclosed in Patent Document 2.

  Furthermore, a plurality of stretch-peelable adhesive heat conductive tapes are arranged so that the PDP and the chassis member are in close contact with each other. A technique for suppressing the occurrence is disclosed in Patent Document 3.

JP 2004-333904 A JP 2007-171224 A JP 2006-64864 A

  In the display device described in Patent Document 1, an adhesive heat conductive member is applied in a line shape, and the panel and the chassis are directly brought into contact with the heat conductive member to be fixed to the heat conductive member. Air bubbles are prevented from entering to improve thermal conductivity. In addition, by providing the heat conductive member in a line shape, air can be convected in the gap between the display panel and the holding plate to promote heat dissipation. However, in order to convect the air in the gap portion formed by the linear application of the heat conductive member, it is necessary to increase the gap as an air passage and increase the amount of air flow. However, on the contrary, the heat conduction performance and the fixing strength of the heat conductive member are deteriorated, but there is no description about a solution for this trade-off.

  In the flat display device described in Patent Document 2, when the display panel is cooled, the display panel and the chassis member are discretely coated with a hot-melt adhesive having adhesiveness filled with a thermal conductivity-imparting agent. Are connected. In order to avoid a decrease in heat conduction performance due to discrete application of the heat conductive member, consideration has been given to the application area, the application thickness, the width of the application gap, etc., but depending on the heat conduction characteristics of the heat conductive member Since it is heat transfer, the smaller the shape of the gap portion, the less the luminance unevenness, and it can be said that the effect of discrete application must be limited. In addition, no measures are taken into consideration for the improvement.

  The plasma display device described in Patent Document 3 is provided with a plurality of stretch-peeling type adhesive heat conductive tapes for bringing a chassis member into close contact with the panel for cooling the panel. The adjacent adhesive heat conductive tape is divided at different positions to avoid the occurrence of local temperature gradients due to the continuous arrangement of regions having different heat conductivities. However, there is no mention of the problem that the regions having different thermal conductivities are continuously formed in a vertical row. In addition, no consideration is given to the formation of a velocity boundary layer by air flow in the dividing portion.

  In the conventional technology as described above, there is no consideration about heat transfer to the chassis member in the heat conduction member when cooling the self-luminous display panel, but there is no contrivance regarding heat transfer to the air in the gap, and workability is improved. There is a problem that must be solved as an efficient cooling structure.

  In order to solve the above problems, the present invention has a display panel having a plurality of display cells, a chassis member fixed to the display panel, and an adhesive property for fixing the display panel and the chassis member. In a flat display device comprising a heat conductive member, the heat conductive member is installed at a predetermined angle with respect to the edge of the display panel, and is discretely attached to a plurality of strips to form the display panel and the chassis member. Is fixed.

  With the above configuration, it is possible to provide a heat cooling structure with good workability and low cost against heat generation of the display panel in the flat display device, and to provide a flat display device that obtains efficient cooling performance.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a flat display device according to the present invention. In FIG. 1, some components are shown in a transparent manner for easy understanding. Inside the housing 2 of the flat display device 1, a display panel 3 for displaying information and a chassis member 5 for holding the circuit board 4 via a holding member (not shown) are provided. The display panel 3 is a self-luminous type typified by a plasma display, and a plurality of display cells are arranged in a matrix. Therefore, the display panel 3 generates heat by displaying light emission. A chassis member 5 made of a metallic aluminum material having excellent thermal conductivity in order to make this local heat generation uniform and dissipate heat is fixed to the display panel 3 by an adhesive thermal conductive member 6. ing. Here, the heat conductive member 6 is discretely attached to the edge of the display panel 3 with a predetermined angle. Forcible ventilation is performed by a fan or the like (not shown) in the gap between the heat conductive members 6 constituted by discrete attachment of the heat conductive members 6. Moreover, this fan may be shared with the fan which ventilates the air for ventilating the chassis member and converting heat from the chassis member.

  In this structure, the chassis member 5 transfers heat generated in the display panel 3 through a thermal connection with the heat conductive member 6, and a solid arrow is drawn on the chassis member 5 due to the heat conduction characteristics of the chassis member 5. As shown, the thermal diffusion is performed to reduce the temperature unevenness of the display panel 3.

  Further, the heat diffused on the chassis member 5 is thermally converted into air that is in a thermally connected state on the surface of the chassis member 5 and flows in the direction of the white arrow. It is cooling. On the other hand, because the chassis member 5 and the display panel 3 are fixed by the adhesiveness of the heat conductive member 6, the chassis member 5 also serves to reinforce the display panel 3.

  Here, the fixing performance of the heat conductive member 6 that fixes the chassis member 5 to the display panel 3 and the heat conductive performance will be described in detail.

  2, 3, and 4 are conceptual diagrams illustrating an example of a state in which a thermally conductive member is attached in the present invention. FIG. 5 is a diagram schematically showing a local heat generation state in the flat display device of the present invention.

  The attached shape and the number of attachments of the heat conductive member 6 shown in FIGS. 2 to 5 are conceptually described for easy understanding of the description, and are not limited to those shown in the drawings. Absent.

  The heat conductive member 6 according to the present embodiment is attached to the display panel 3 with a predetermined angle (α) with respect to the end side (for example, the lower end side) of the display panel 3.

  Although the heat conductive member 6 is described as being attached to the display panel 3, the heat conductive member 6 may be attached to the chassis member 5 because the display panel 3 and the chassis member 5 are fixed.

  In addition, the heat conductive member 6 of the present embodiment is preferably a coating type adhesive member from the viewpoint of workability, and therefore a hot melt adhesive will be described as an example, but is not limited to this material.

First, the fixing performance of the heat conductive member 6 will be described. The hot melt adhesive used as the heat conductive member 6 of the present embodiment is basically a base material obtained by hydrogenating a styrene / isoprene / styrene copolymer rubber which is a rubber elastic component on a base material. The tensile shear strength of the heat conductive member (fixing member) 6 can be about 15 N / cm ² (1.5 kg / cm ² ) in an environment of 70 ° C. when attached under general conditions. For example, when applied to the entire back surface (area: about 5000 cm ² ) of the display panel 3 in the 42-type flat display device 1, it indicates that a load of about 7.5 tons can be fixed and held. On the other hand, since the weight of the 42-type PDP 3 is about 8 kg, the required application area of the fixing member 6 for holding the PDP 3 is about 1/900 of the surface area of the display panel 3 in the calculation. It will be good. However, in practice, in order to ensure reliability, the application area will be set in consideration of safety factors, etc. Show. Therefore, the discrete attachment conditions of the heat conductive member 6 are set in terms of heat conduction performance.

  Next, the heat conductive performance in the attached state of the heat conductive member 6 of this embodiment is demonstrated. The thermal conductivity of the hot melt adhesive used as the heat conductive member 6 in this embodiment is about 0.43 W / m · K. This is because the thermal conductivity of the glass substrate in the display panel 3 is about 0.64 W / m · K, and the thermal conductivity is never good. However, when the thermal connection between the display panel 3 and the chassis member 5 is attempted, the thermal conductive member 6 of hot melt adhesive is interposed between the display panel 3 and the chassis member 5 as described above. This is because the thermal conductivity is improved by increasing the contact ratio with respect to the dispersed contact state at the interface. Therefore, it is originally assumed that it is preferable to improve the thermal conductivity characteristics of the heat conductive member 6 in order to improve the heat transfer performance of the heat conductive member 6. This is an inclusion for obtaining the effect of reducing the dispersed contact in transferring heat to the chassis member 5 and does not require much heat diffusion action in the thickness direction of the heat conductive member 6. From this, it can be said that there is little meaning to improve the thermal conductivity in the thickness direction until the adhesive force is reduced. In other words, it can be said that the heat conductive member 6 is preferably made as thin as possible in consideration of heat transfer from the display panel 3 to the chassis member 5.

  The heat generated by the display panel 3 is transferred to the chassis member 5 through the heat conductive member 6, and then on the chassis member 5 by the heat conductivity (236 W / m · K) of the aluminum material of the chassis member 5. Is diffused and released from the local heat generation state, resulting in a uniform temperature distribution state. That is, the heat diffusion in the chassis member 5 is realized by the thermal conductivity of the chassis member 5.

  However, the heat transfer and heat conduction states described above are the contents when the heat generation of the display panel 3 performs heat transfer through the attachment portion of the heat conductive member 6, and the heat conductive member 6 is attached. In the gap portion that is not, it can be assumed that the heat conversion state is different from the above situation.

  Here, the heat transfer state in the gap portion of the heat conductive member 6 will be described. The gap portion interposes an air layer corresponding to the thickness of the heat conductive member 6 provided between the display panel 3 and the chassis member 5. Since the thermal conductivity of air is 0.0241 W / m · K, which is as small as about 1/15 to 1/20 of that of the heat conductive member 6, the display panel 3 to the chassis member 5 in the gap portion. And the heat transfer performance from the display panel 3 to the chassis member 5 at the portion where the heat conductive member 6 is attached are in a greatly different state.

  For this reason, local heat generation in the display panel 3 instantaneously causes temperature unevenness in the display panel 3. This phenomenon is equivalent to the fact that bubbles generated in the heat conductive sheet impede heat transfer, and this problem is easily assumed.

  Therefore, the attachment of the heat conductive member 6 is preferably to reduce the gap portion through the air layer as much as possible. However, this increases the attachment area of the heat conductive member 6 and is arranged discretely. This is not desirable in terms of workability and cost.

  For this reason, the air layer in the gap portion does not act as a heat conductive member from the display panel 3 to the chassis member 5, but converts heat of the display panel 3 in the air layer and transfers heat to the outside. It is a good idea to consider measures to be used as members. When the air layer in the gap portion is considered as the former heat conductive member, it is necessary to make the air layer volume in the gap portion as small as possible, but the air facing the latter display panel 3 is converted into heat with the display panel 3. In the case of a medium, it is preferable to reduce the thickness of the thermal boundary layer and increase the contact area in order to obtain a predetermined heat conversion amount. That is, the width area of the gap portion is increased, and the thickness formed by the heat conductive member 6 is decreased.

  In order to improve the heat transfer coefficient of air, forced ventilation is preferable instead of natural air convection.

  Here, the heat conversion state by attachment of the heat conductive member 6 of a present Example is demonstrated. The attached state of the heat conductive member 6 described in FIG. 2 shows the attachment of the basic form in the present embodiment, and a predetermined angle (α) with respect to the lower end side of the display panel 3. It is provided as a substantially rectangular shape having a predetermined width (T) and length (L), and is divided with a gap (D2) while being divided with a gap (D1). Although details of the meaning of dividing the heat conductive member 6 into a plurality of gaps (D1) in the attached length direction will be described later, it is configured as an air ventilation path.

  Since the heat conductive member 6 is provided at a predetermined angle (α) with respect to the lower end side of the display panel 3, the discrete parallel gaps (D2) of the heat conductive member 6 are, for example, display A ventilation channel is formed from the lower side edge side of the panel 3 toward the left side edge side, or from the right side edge side toward the upper side edge side, as indicated by a white arrow. That is, in the present embodiment, the conventional air flow channel air inlet in the gap provided from the lower side end side to the upper side end side of the display panel 3 that expects natural convection is only from the lower side end side. It can be enlarged by providing at least two sides of the lower side edge and the side edge. In addition, since it is necessary to make the attachment area of the heat conductive member 6 into an area equivalent to the case where it is attached in parallel to the conventional side from the viewpoint of the strength of the fixing force, the geometrical shape The amount of ventilation per predetermined time is the same regardless of the difference in the state of attachment of the heat conductive member 6, but the ease of inflow of low-temperature air is enhanced by expanding the forced ventilation port. ing. That is, if the ventilation is the same inflow rate, the flow rate may be small, the pressure loss can be reduced, and the desired flow rate can be easily obtained.

  Furthermore, as shown in comparison with the conventional state (A) of the thermally conductive member shown in FIG. 5 and the state (B) of the thermally conductive member of this embodiment, the matrix is vertically and horizontally arranged. The closeness of the information of the arranged display cells tends to be larger in the information of the display cells adjacent in the vertical direction and the horizontal direction than the information of the display cells adjacent in the oblique direction. In the case where the state of the heat generating part is as shown in FIG. 5, in this embodiment, the gap (D2) as the ventilation path is provided at a predetermined angle (α), so that the ventilation for heat conversion is provided. Will flow diagonally over the display cells arranged in a matrix. This shortens the ventilation path length (H) in the heat generating part and can suppress the temperature rise of the air with respect to the upper part of the ventilation.

  Further, as shown in FIG. 2, the heat conducting member 6 is divided at a predetermined position with a gap (D1) having a predetermined angle with respect to the lower end side portion, so that the heat generating portion is ventilated. Then, the air whose temperature has risen can flow into the ventilation channel of the adjacent gap as indicated by the filled arrow by the gap (D1). Therefore, the velocity boundary layer of the air in the adjacent gap can be easily mixed, a new velocity boundary layer can be formed, and the heat transfer coefficient between each flow channel can be averaged. It can be converted.

  In the embodiment shown in FIG. 2, the heat conductive member 6 is provided with a predetermined angle (α) with respect to the long side and the short side of the display panel 3 so as to be substantially parallel to each other and substantially equal in width (T). It has been described as being attached in a plurality of lines at substantially equal intervals. However, this is for simplifying the work in attaching the heat conductive member 6 and for making the explanation easy to understand, and the present invention is limited to the one provided in the form described in the first embodiment. Not. That is, the heat conductive member 6 may be provided in other forms, which will be described below as another embodiment of the present invention.

In the embodiment of the attached state of the heat conductive member 6 shown in FIG. 3, the predetermined angle (α) of the heat conductive member 6 has a plurality of different angles (α1, α2, α3,...). is doing. This structure is to make the opening length (E1) of the air inlet larger than the opening length (E2) of the outlet.
In general, in the air flow, the air transferred from the display panel 3 flows out toward the upper end side. However, as the air flows through the upper end side, the temperature rises and the heat transfer is saturated. Approaching and reducing heat transfer efficiency.
Therefore, in order to ensure the heat transfer performance on the upper end side, it is necessary to increase the air flow rate at the ventilation outlet on the upper end side.

  That is, on the lower end side (E1 side) of the display panel 3, there is room for the air saturation state, and since the heat conversion capacity is large, heat exchange to the air is achieved by a slow flow rate, and the upper end side of the display panel 3 On the (E2 side), the heat transfer capacity is small because the heat transfer of the air is close to saturation, and the flow inlet air is volume-expanded. By making the opening length (E1) of the display panel larger than the opening length (E2) of the outlet, efficient heat transfer can be performed from local heat generation of the display panel 3. In FIG. 3, the heat conductive member 6 is not divided, but as described above, the heat conversion efficiency can be further improved by being divided.

  Further, in order to form a gap in which the opening length (E1) of the inflow port is larger than the opening length (E2) of the outflow port (E1> E2), the width of the heat conductive member (lower end side: T1, upper end side: The heat conductive member 6 may be attached so that T2) is not constant and gradually increases or decreases (T1 <T2) along the longitudinal direction of the heat conductive member.

  The attached state of the heat conducting member 6 shown in FIG. 4 is obtained by attaching a predetermined angle (α) to the long end side of the display panel 3 greatly different (α1, α2,...). The air inlet is configured as three sides of both side edges and a lower edge.

  With this configuration, a larger air flow rate can be secured and higher heat conversion performance can be obtained. Also in FIG. 4, similarly to FIG. 3, the heat conductive member 6 may be divided and attached.

  In the embodiment as described above, the thermal conductive member 6 is provided discretely at a predetermined angle with respect to the edge of the display panel 3, and the air inlet end is also used as the air outlet end. By making it larger, and by providing a gap that divides the flow path, it becomes possible to improve the heat conversion efficiency by forced ventilation to the gap formed by the heat conducting member 6, and at low cost, work A flat display device having a good cooling structure can be provided.

It is a schematic block diagram of the flat display apparatus in this invention. It is the conceptual diagram which showed the Example of the attachment state of the heat conductive member in this invention. It is the conceptual diagram which showed the Example of the attachment state of the heat conductive member in this invention. It is the conceptual diagram which showed the Example of the attachment state of the heat conductive member in this invention. It is the figure which showed typically the local heat_generation | fever state in the flat display apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Flat panel display device, 2 ... Housing | casing, 3 ... Display panel, 4 ... Circuit board 5 ... Chassis member, 6 ... Thermally conductive member,

Claims (3)

A flat panel comprising a display panel having a plurality of display cells, a chassis member fixed to the back side of the display panel, and a thermally conductive member having fixing properties for fixing the display panel and the chassis member. A display device,
The thermal conductive members are discretely attached to a plurality of strips at a predetermined angle with respect to the edge of the display panel, and the plurality of thermal conductive members are attached to the strips by fixing the display panel and the chassis member . A ventilation channel is formed between the heat conductive members,
The display panel end of the plurality of thermally conductive members is such that the opening length of the air inlet on the lower end side of the display panel of the ventilation channel is larger than the opening length of the air outlet on the lower end side of the display panel. A flat display device characterized by different angles with respect to the sides . The flat display device according to claim 1,
Gap between the thermally conductive member formed by a discrete annexed of the thermally conductive member, two sides ends of the display panel, or have the air inlet at the three sides end, the air inlet A flat display device characterized by being configured to be ventilated through the ventilation channel . 3. The flat display device according to claim 1, wherein the heat conductive member is provided in a substantially rectangular shape and divided into a plurality of parts.
A flat display device characterized by that.

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