JP2001352022A - Heat-dissipating mounting structure for driver ic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-dissipating mounting structure, with which heat generated by a driver IC for the scan and the address of a plasma display can be made to escape effectively. SOLUTION: The driver IC is brought into contact with a heat conductive sheet via a heat conductive chassis, and the heat of the driver IC is dissipated. In this case, the driver IC is pressed to the heat conductive sheet and the heat conductive chassis via an elastic member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipation mounting structure of a driver IC, and more particularly to a driver I for a plasma display device.
C relates to the heat dissipation mounting structure.

[0002]

2. Description of the Related Art A display device using a plasma display panel is a next-generation large-sized television, because it has a wide viewing angle and is easy to form a large screen in addition to a small depth, which is a general feature of a flat display. Is attracting attention as a leading display candidate. However, unlike a device using a liquid crystal panel, which is the same flat display, a plasma display panel consumes a large amount of power because it is a display by a discharge phenomenon. Therefore, there is a problem that the power consumption of the driver IC that guides the display signal to the panel is large.

Conventionally, the mounting structure of the driver IC has been wire bonding. However, as in the case of the preceding liquid crystal, as the production volume increases, the productivity of wire bonding is becoming a problem. Therefore, a flip-chip method suitable for mass production is being sought. However, unlike liquid crystal, a structure that pursues heat dissipation even in flip-chip mounting is required. Japanese Patent Application Laid-Open No. Hei 10-260641 proposes, as an example of such a method, a structure in which a single aluminum plate supporting a plasma display panel is stretched more than usual and a driver IC is attached to the stretched portion.
Although this structure is rational, it does not specifically disclose a method of fixing the driver IC for securing heat conduction. On the other hand, Japanese Patent Application Laid-Open No. 9-27515 discloses an example of a structure that does not aim at heat conduction but maintains contact by applying pressure from the outside.

Further, a conventional plasma display panel will be described with reference to FIG.

FIGS. 2A and 2C are cross-sectional views of a part of a conventional plasma display panel.
2 (b) and FIG. 2 (d) are FIGS. 2 (a) and 2 (c), respectively.
3 is a partially enlarged cross-sectional view of FIG. Note that this cross-sectional view is a cross-sectional view of a part of the panel, but the relationship with the whole is clear with reference to FIG. In FIG. 2, an address IC 201 and a flexible wiring board 202 are combined to form an address I.
It is a C module. The address IC 201 is connected to the flexible wiring board 202 in a flip-chip structure. That is, the electrical connection is realized by bonding the gold bump 205 formed on the circuit forming surface of the address IC 201 to the copper wiring 209 formed on the surface of the flexible wiring board 202.

In this structure, in order to release heat generated in the address IC 201, it is necessary to use a surface opposite to a circuit forming surface. The reason is that the gold bump 205 having good heat conductivity is used on the circuit forming side of the address IC 201, but since the area of the gold bump 205 is small, the heat is transferred to the flexible wiring board 202 by the ACF (different type). Conductive film) 206, but AC
Since the thermal conductivity of F206 is small, flexible wiring board 2
This is because the heat is hardly transmitted to the flexible wiring board 02 and the thermal conductivity of the flexible wiring board 202 itself is small. Therefore, the heat conductive sheet 20 which is an adhesive member having good heat conductivity is used.
3 will dissipate heat to the aluminum chassis 204. The heat conductive sheet 203 is a resin, and is a sticky sheet using a material having a thermal conductivity of 1 to 10 W / m · K, which is significantly higher in thermal conductivity than ordinary resin.

[0007]

However, if a resin having a high thermal conductivity (for example, boron nitride) is mixed with a resin in order to increase the thermal conductivity, it is difficult to improve the adhesive performance of the thermal conductive sheet 203. . 2A and 2B, when the bonding surface of the aluminum chassis 204 is enlarged, as shown in the enlarged view of FIG. Has irregularities on the surface, and an air layer is formed in the surface. Even if the aluminum chassis 204 and the heat conductive sheet 203 are initially adhered by this air layer, as shown in FIG.
As shown in (c) and (d), the space between the heat conductive sheet 203 and the aluminum chassis 204 comes off. FIG.
(B) As is clearer, the aluminum chassis 20
The thermal conductivity is degraded by an air layer formed by the unevenness of the surface of the bonding portion between the heat conductive sheet 4 and the heat conductive sheet 203. That is, since air has poor thermal conductivity, the heat conductive sheet 20 having good thermal conductivity is used.
Even when using No. 3, sufficient heat is not transmitted to the air layer. As described above, there is no disclosure in the related art of a structure for effectively dissipating heat generated in a driver IC having a flip-chip structure.

An object of the present invention is to provide a mounting structure for effectively guiding heat generated in a driver IC having a flip chip structure to the outside.

[0009]

In order to achieve the above object, according to the present invention, a plurality of drivers I are arranged in a line.
The back surface of the circuit forming surface of C is fixed to a part of an aluminum plate supporting the panel via a resin having high thermal conductivity, and the circuit forming surface of the driver IC is connected to the connecting metal formed thereon. Are electrically and mechanically connected to the wiring surface of the wiring board via the projections of the wiring board, and are connected to the driver IC of the wiring board on the other surface thereof through a resin, metal or inorganic elastic member. One holding member is attached to each driver IC.

The details will be described below.

In the first aspect of the present invention, the heat dissipating mounting structure of the driver IC includes a heat conductive chassis, a driver IC having a circuit forming surface and a non-circuit forming surface, the heat conductive chassis and the driver IC. A heat conductive member disposed between the non-circuit forming surfaces, a wiring board on which wiring formed on one surface is electrically connected to the circuit forming surface of the driver IC, and an elastic member on the other surface of the wiring board , And the heat generated from the driver IC is radiated through the heat conductive member and the heat conductive chassis. In the first invention, a pressing member is provided, and the driver IC is configured to press the driver IC against the heat conductive member and the heat conductive chassis via the elastic member by the pressing member.

According to a second aspect of the present invention, there is provided a mounting structure of a plasma display device having a plasma display panel, an aluminum chassis supporting the plasma display panel, and a driver IC, wherein a plurality of the display devices are arranged in a line, and a circuit forming surface is provided. Driver I having non-circuit forming surface
C. placing a thermally conductive resin between the non-circuit forming surface of C and the aluminum chassis, electrically and mechanically connecting the surface of the wiring board on which the wiring is provided to the circuit forming surface of the driver IC, The holding member is attached to the other surface of the wiring board via an elastic member. In the second invention,
One pressing member is provided for a plurality of the driver ICs. When a necessary pressure is applied to the non-circuit forming surface of the driver IC by the pressing member, the elastic member is
It is configured to be deformed by m to 10 mm. The holding member is screwed to the aluminum chassis. Further, a clip is fixed between the aluminum chassis and the holding plate.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments according to the present invention will be described below with reference to the drawings using examples. Note that the present invention is not limited to these examples. First, FIGS. 1 and 3
The principle of the present invention will be described with reference to FIG. FIG. 1 is a perspective view of an embodiment of a plasma display panel according to the present invention as viewed from the rear side. In the figure, reference numeral 101 denotes a front panel which is the front of a product such as a television. The material is glass. The screen size of this embodiment is 42 inches, and the diagonal size of the screen is less than 1 m10 cm. Front panel 10
1. Behind 1 is a rear panel 102 and a front panel 10
A small chamber (cell) for plasma emission is provided by reducing the pressure of about 0.1 mm between the first panel 1 and the back panel 102.
The number is 480 in the vertical direction and 2556 in the horizontal direction (852
(× 3 primary colors) and are arranged in a grid pattern. The two glass panels 101 and 102 are mechanically supported by an aluminum plate having a thickness of 1 mm. The aluminum plate is, for example, a single plate or a plate connected to another aluminum plate.
As shown. Also, aluminum chassis 103
Also mechanically supports the driving circuit board of the plasma display device 100.

The driving circuit board of the plasma display device 100 is composed of a power supply circuit board 10 located at the upper part of the center.
4. It is composed of a Y-side sustain circuit board 106 and an X-side sustain circuit board 107 located on the left and right, and a logic circuit board 105 located below the center. The power supply circuit board 104 generates a voltage required internally by using a voltage supplied from the outside. The Y-side sustain circuit board 106 and the X-side sustain circuit board 107 supply electric power for plasma emission in pairs. The logic circuit board 105 converts an image signal into a signal for plasma emission and supplies the signal to each pixel.

In the plasma display panel according to the present invention, for example, one pixel has three electrodes. X electrodes and Y electrodes are arranged on the front panel 101, and A (address) electrodes are arranged on the back panel 102.
The image signal is stored by the Y electrode and the A electrode, and is displayed by the X electrode and the Y electrode. A driver IC is used to store an image signal in each pixel. Among the driver ICs, the one that communicates with the A electrode is called the address IC module 113, and the one that communicates with the Y electrode is called the scan IC module 111. Further, the X electrodes are directly connected to the X electrodes via the X flexible wiring board 112 from the X side sustain circuit board 107 without using an IC. Between the address IC module 113 and the logic circuit board 105, the address bus board 1 is used as a relay board.
08, a Y bus board 109 is provided as a relay board between the scan IC module 111 and the Y-side sustain circuit board 106, and an X flexible wiring board 112 is provided.
An X bus board 110 is provided between the X-side sustain circuit board 107 and the X side sustain circuit board 107 as a relay board.

The scan IC module 111 and the address IC module 113 generate a large amount of heat. for that reason,
A heat dissipation structure is essential. In the figure, the Y holding plate 114 and the address holding plate 115 are seen as part of the heat dissipation structure. This embodiment relates to a heat dissipation structure of the scan IC module 111 and the address IC module 113. Since there is basically no difference between the scan IC module 111 and the address IC module 113, and the address IC module 113 generates a larger amount of heat, the address IC module 113 will be described.

The heat conductive sheet 203 described with reference to FIG.
The principle for simultaneously solving the problem of peeling and the deterioration of the thermal conductivity due to the air layer will be described with reference to FIG. FIG.
3A is a cross-sectional view illustrating a part of the AA cross section of FIG. 1 for explaining the principle of the present invention, and FIG. 3B is a partially enlarged cross-sectional view of FIG. As shown in the figure, in this embodiment, an address holding plate 115 is used. As a result, FIG.
At the same time as the problem of peeling as shown in (b) is solved, the proportion of the air layer becomes smaller as shown in FIG. 3 (b), as shown in FIGS. 3 (a) and 3 (b). Heat conduction is greatly improved.

More specifically, the address holding plate 1
It is necessary to sandwich the elastic member 308 for buffering between the flexible wiring board 304 and the flexible wiring board 304. As shown in FIG. 1, a large number of address IC modules 113 are provided and arranged in a line. Instead of fixing them individually, it is realistic to fix a plurality of them collectively. For this reason, the address I in the vicinity of the fixed portion by the bolt or the like is used.
Address I located far from C module and fixed part
In C, the distance between the flexible wiring board 304 and the aluminum chassis 103 is different. In addition, the aluminum chassis 103 is generally a single plate, and is bent or distorted, so that the distance between the flexible wiring board 304 and the aluminum chassis 103 is not constant. On the other hand, it is desirable to make the thickness of the heat conductive sheet 306 substantially uniform between the address ICs. Therefore, in order to absorb the difference in the distance between the flexible wiring board 304 and the aluminum chassis 103, the elastic member 308 is required.
Of course, even when individually fixed, the elastic members 308
The elastic pressure of the elastic members 3
08 is mandatory.

FIG. 4 is a sectional view taken along the line AA of FIG. 1 showing one embodiment of the heat radiation mounting structure of the driver IC according to the present invention.
The periphery of the address IC module 113 is enlarged and shown in more detail than FIG. FIG. 1 also shows a detailed structure that cannot be displayed. Parts not directly related to the present embodiment are omitted. Address IC module 11
3 is an address IC301, ACF (anisotropic conductive film)
303, a flexible wiring board 304, a gold bump 302 of the address IC 301 inserted into the ACF 303, and a copper wiring 309 of the flexible wiring board 304.

The address IC 301 is connected to the flexible wiring board 3 via the gold bump 302 formed on the circuit forming surface.
04 is electrically connected to the copper wiring 309. Here, the ACF 303 is used for connection. ACF
Numeral 303 denotes conductive particles dispersed in an insulating resin.
It shows conductivity when pressed against the copper wiring 309 of FIG. A connector 305 is used to connect the flexible wiring board 304 and the address bus board 108. Note that the address bus board 108 (specifically, a printed board) is supported by an insulating bar 307 so that the address bus board 108 does not contact the aluminum chassis 103.

In this embodiment, the structure is such that heat is released from the surface of the address IC 301 opposite to the circuit forming surface, and a heat conductive sheet 306 is used. At this time, as described with reference to FIG. 3, it is important to appropriately deform the heat conductive sheet 306 to increase the area contributing to heat conduction. That is, it is necessary to increase the contact area by making it possible to make contact with the unevenness of the aluminum chassis 204 to increase the thermal conductivity. Further, it is necessary to keep the thickness of the heat conductive sheet 306 to some extent. That is, as shown in FIGS. 2C and 2D, the address IC 201 and the aluminum chassis 204 are not necessarily parallel, and a part of the corner of the peripheral edge of the address IC 201 bites into the heat conductive sheet 203, and Since the heat conductive sheet 203 may be broken and come into contact with the aluminum chassis 204, it is necessary to maintain the thickness of the heat conductive sheet 306 to some extent in order to prevent this.

For this purpose, it is necessary to press the heat conductive sheet 306 appropriately. A pressure of 30 g / cm 2 to 100 g / cm 2 is required as a pressure for keeping the heat conductive sheet 306 at a sufficient thickness while sufficiently lowering the thermal resistance. However, the heat conductive sheet 306 must be made as thin as possible to keep the thermal resistance low. In this embodiment, it is 0.5 mm. The heat conduction sheet 30
When converted to the amount of deformation of No. 6, the value is as small as 0.1 mm to 0.2 mm. The pressure applied to the heat conductive sheet 306,
In other words, it is important and difficult to control the amount of deformation of the heat conductive sheet 306. As shown in FIG. 1, there are many address IC modules 113. It is practically impossible to adjust the deformation amount of the heat conductive sheet 306 one by one. Further, the address holding plate 115
Is one in this embodiment, and all the address IC modules 113 are commonly pressed. In addition, the fixing method is a hole (not shown) provided as appropriate in the address holding plate 115.
Is realized by passing a screw 119 through a screw hole provided at a corresponding location of the aluminum chassis 103. The screw 119 is connected to each address IC 30 as shown in FIG.
One screw may be provided, but generally, two screws 119 are provided.
, A plurality of address ICs 301 are fixed.

Therefore, the property of the elastic member 308 becomes important. In this embodiment, an elastic resin 308a is provided as the elastic member. It is necessary that the elastic resin has such a property that even if the address pressing plate 115 is fixed to a certain degree of roughness, a desired pressing force can be applied to all the heat conductive sheets 306. From our experience,
When one plasma display device 100 is covered by one address holding plate 115, the difference in the holding distance of the address holding plate 115 depending on the location of the heat conductive sheet 306 is 5 m.
m. That is, if the elastic resin 308 is deformed by 1 mm and the necessary minimum pressure is applied to the heat conductive sheet 306, the maximum pressure of the heat conductive sheet 306 must be provided by the deformation of the elastic resin 308 by 6 mm. No. Therefore, as the elastic resin 308, a material having a softness of about 1/50 that of the heat conductive sheet 306 was selected. This material is, for example, rubber-like silicone.

Hereinafter, another embodiment of the present invention will be described with reference to FIG. FIG. 5 is a sectional view taken along line AA of FIG. 1 showing another embodiment of the heat radiation mounting structure of the driver IC according to the present invention. The basic structure of this embodiment is the same as that of the embodiment shown in FIG.
The heat generated by the address IC 301 mounted on the flexible wiring board 304 connected to the aluminum wiring 103 is guided to the aluminum chassis 103 through the heat conductive sheet 306. At this time, in order to supply an appropriate pressing force to the heat conductive sheet 306, the pressing is performed by the address pressing plate 115.

In this embodiment, a metal spring 308 is used instead of the elastic resin 308a used in the embodiment shown in FIG.
b was used. Strictly, plastic deformation easily occurs when the resin is used for a long time. There is also a problem of deterioration due to temperature environment and humidity environment. Therefore, in this embodiment, a metal spring material (specifically, phosphor bronze) is used. The use of the spring resulted in a structure having excellent long-term reliability as compared with the example using the resin. In addition, a clip (not shown) is used to fix the address holding plate 115. When clipping is performed between the plurality of address IC modules 113 arranged in the horizontal direction, the address holding plate 115 and the aluminum chassis 103 are sandwiched by U-shaped clips. When clipping the portion where the address IC module 113 is arranged, the flexible wiring board 304 is bent into a U-shape, and one surface thereof is brought into contact with the aluminum chassis 103 side, and the flexible wiring board 304 bent into a U-shape is formed. And the address holding plate 411 are sandwiched and fixed by U-shaped clips. The elasticity of the clip adds to the elasticity of the spring 308b, increasing the flexibility of the overall structure.

In the present invention, considering the bending and distortion of the aluminum chassis 103, the address IC
With respect to the pressing force for pressing the aluminum chassis 103 on the non-circuit-forming surface of 301, the elastic member has a thickness of 1 mm to 10 mm.
mm. Further, in the present invention, an elastic resin or a spring may be attached to the position of the address holding plate corresponding to the interval where the address ICs are arranged, and then may be arranged to face the flexible wiring board.

[0027]

As described above, according to the present invention, the heat generated from the driver IC can be efficiently guided to the outside.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of a plasma display panel according to the present invention as viewed from the back side.

FIG. 2 is a partial cross-sectional view and a partially enlarged cross-sectional view of a conventional plasma display panel.

FIG. 3 is a cross-sectional view showing a part of the AA cross section of FIG. 1 and a partially enlarged cross-sectional view for explaining the principle of the present invention.

FIG. 4 is a sectional view taken along the line AA of FIG. 1 showing an embodiment of a heat radiation mounting structure of the driver IC according to the present invention.

FIG. 5 is a cross-sectional view taken along the line AA of FIG. 1 showing another embodiment of the heat dissipation mounting structure of the driver IC according to the present invention.

[Explanation of symbols]

Reference Signs List 100 plasma display device, 101 front panel, 102 rear panel, 103 aluminum chassis, 104 power circuit board, 105 logic circuit board, 106 Y-side sustain circuit board, 107 X-side sustain circuit board, 108 ... Address bus board, 109
... Y bus board, 110 ... X bus board, 111 ... Scan IC module, 112 ... X flexible wiring board, 11
3 ... Address IC module, 114 ... Y presser plate, 11
5 ... Address holding plate, 201 ... Address IC, 202 ...
Flexible wiring board, 203 ... thermal conductive sheet, 204 ...
Aluminum chassis, 205: gold bump, 206: A
CF, 207: Address holding plate, 208: Elastic member,
301: Address IC, 302: Gold bump, 303: A
CF, 304: flexible wiring board, 305: connector, 306: heat conductive sheet, 307: insulating rod, 308:
Elastic member, 308a: elastic resin, 308b: spring.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yuji Sano 3-2-1 Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa Fujitsu Hitachi Plasma Display Limited In-house (72) Inventor Michitaka Osawa 3-chome Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa No. 2 Fujitsu Hitachi Plasma Display Limited In-house F-term (reference) 5E322 AA03 AB01 AB04 EA11 FA04 5F036 BB21 BC33 BC35 5G435 AA12 BB06 EE04 EE33 EE36 EE40 EE47 HH02 HH18 LL04

Claims (7)

[Claims] 1. A driver IC having a heat conductive chassis, a circuit forming surface and a non-circuit forming surface, and a heat conductive member disposed between the heat conductive chassis and the non-circuit forming surface of the driver IC. The member and the wiring formed on one side are the driver I
C. a circuit board electrically connected to the circuit forming surface of C, and pressing the other surface of the circuit board via an elastic member to form the driver IC
Wherein the heat generated from the device is dissipated through the heat conductive member and the heat conductive chassis.
C heat dissipation mounting structure. 2. The heat dissipation mounting structure of a driver IC according to claim 1, further comprising a pressing member, wherein the pressing member is connected to the driver IC via the elastic member by the heat conductive member and the heat conductive chassis. A heat dissipating mounting structure for a driver IC, wherein 3. A mounting structure of a plasma display device having a plasma display panel, an aluminum chassis supporting the plasma display panel, and a driver IC, wherein a plurality of the circuits are arranged in a line, and a circuit forming surface and a non-circuit forming surface are arranged. A thermally conductive resin is disposed between the non-circuit forming surface of the driver IC having
Characterized by electrically and mechanically connecting to the circuit forming surface and attaching a pressing member to the other surface of the wiring substrate via an elastic member.
C heat dissipation mounting structure. 4. A driver IC for a plasma display device according to claim 3, wherein said pressing member is provided one for a plurality of said driver ICs. Heat dissipation structure. 5. A heat dissipating mounting structure for a driver IC for a plasma display device according to claim 3, wherein when the pressing member applies a necessary pressure to a non-circuit forming surface of the driver IC, the elastic member has a thickness of 1 mm or more. A heat dissipating mounting structure of a driver IC for a plasma display device, which is deformed by 10 mm. 6. A heat dissipation mounting structure for a driver IC for a plasma display device according to claim 3, wherein said holding member is screwed to said aluminum chassis. 7. A heat dissipating mounting structure for a driver IC for a plasma display device according to claim 3, wherein a clip is fixed between said aluminum chassis and said holding plate with a clip.