JP4455074B2 - Electro-optic device - Google Patents

Description

The present invention relates to a suitable electrical-optical device to cool the heat generated by the semiconductor chip.

2. Description of the Related Art Conventionally, a technique for performing electrical connection between components of an electronic device using a flexible wiring board is known. As a kind of such flexible wiring board, a TCP (Tape Carrier Package) method in which a semiconductor chip is mounted on a flexible wiring board, or an electronic component chipped on a flexible wiring board, such as a semiconductor chip, an LED, A COF (Chip On Film) mounting flexible wiring board with one or more resistors, capacitors, etc., can be mounted in high density and slim package, and has advantages such as low mounting cost. It is often used for mounting a driving IC (driving LSI) in various display devices provided. Recently, it is also used to mount various electronic components such as a CPU, a chip resistor chip and a capacitor.

  In a mounting flexible wiring board on which this type of semiconductor chip, for example, a driving IC is mounted, its input terminal is electrically connected to an output terminal of a circuit board that supplies power and control signals to the driving IC, and the output terminal is electrically connected. It is electrically connected to input terminals connected to the pixels of the optical panel.

  Further, in recent display devices, there is a risk that display quality such as luminance unevenness may be reduced in an electro-optical panel due to an increase in heat generated during operation of a semiconductor chip mounted on a mounting flexible wiring board, for example, a driving IC. There is.

In view of this, it has been proposed to dispose heat generated by the heat generated by the driving IC by providing a conductor pattern substantially not involved in signal input / output in the TCP structure (see, for example, Patent Document 1). .

Japanese Patent Laid-Open No. 10-032229

  However, current-driven electro-optical panels represented by organic EL panels require a larger amount of drive current than voltage-driven panels such as liquid crystal display panels. In particular, a large current flows through the power supply wiring pattern of the mounting flexible wiring board connected to the organic EL panel, and the heat generation of the driving IC becomes significant due to this large current. Therefore, it is required to dissipate heat more efficiently than the structure of the conductive pattern formed on the conventional mounting flexible wiring board.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a can Ru electric optical apparatus to rapidly cool the heat generated by the heat generation of the semiconductor chip.

In order to achieve the above-described object, the electro-optical device according to claim 1 of the present invention is characterized in that an insulating substrate having flexibility and a semiconductor chip mounted on the insulating substrate are provided. A wiring pattern connected to each of the plurality of electrodes of the semiconductor chip, and an insulating protective film covering the wiring pattern, wherein at least one of the wiring patterns includes heat from the semiconductor chip. A heat dissipating pattern for radiating heat is formed to extend, and the heat dissipating pattern has an externally exposed portion that is not covered with the insulating protective film, and the insulating substrate is thickened in the externally exposed portion. and mounting the flexible circuit board being formed with a through hole penetrating in the direction, and the electro-optical panel connected to an output terminal of the mounting flexible wiring board, which is connected to an input terminal of the mounting flexible wiring board A heat dissipation land made of a conductor material is formed on the circuit board, and an opposing region partially overlapping with the mounting flexible wiring board is formed, and the heat dissipation land is formed in the opposing region. The land and the heat radiation pattern of the mounting flexible wiring board are connected to each other by a bonding material that conducts heat conduction quickly and efficiently through the through hole. A land exposed portion that extends and is exposed to the outside is formed.

By adopting such a configuration, since the heat dissipation pattern is connected to the semiconductor chip, the heat generated by the heat generation of the semiconductor chip can be efficiently dissipated from the externally exposed portion of the heat dissipation pattern. Furthermore, it can be easily connected to an external heat dissipation land using the through hole. In addition, the externally exposed portion of the heat dissipation pattern and the heat dissipation land of the circuit board are connected to each other by a bonding material that conducts heat conduction quickly and efficiently through the through hole. The heat conduction to the semiconductor chip can be efficiently performed, and the capacity of the heat sink that cools and dissipates the heat generated by the semiconductor chip can be increased.

  Moreover, it is preferable that the said heat radiation pattern is connected to the power supply wiring pattern or the grounding wiring pattern among the said wiring patterns. By adopting such a configuration, it is possible to directly dissipate a wiring pattern in which a large current flows and is easily heated.

Further, it is preferable that before Symbol electro-optical panel is an organic EL panel.

According to electric optical apparatus of the present invention exhibits the excellent effects such it is possible to cool the heat generated by the heat generation of the semiconductor chip quickly.

  The present invention will be described below with reference to embodiments shown in the drawings.

  FIG. 1 is a schematic structural diagram showing, in a simplified manner, main portions of an embodiment of an electro-optical device according to the invention.

  As shown in FIG. 1, the electro-optical device 1 of the present embodiment has a mounting flexible wiring board 3 on which a driving IC 2 as a semiconductor chip is mounted. An input terminal (see FIG. 2) 31 a provided on the wiring pattern 31 of the mounting flexible wiring board 3 is provided on the wiring pattern 41 of the circuit board 4 for supplying power and control signals to the driving IC 2. A connection terminal (see FIG. 4) 41a is electrically connected by a joining member 5 such as solder. Further, an output terminal (see FIG. 2) 31b provided in the wiring pattern 31 of the mounting flexible wiring board 3 is a panel provided in the wiring pattern 61 connected to the pixels of the current drive type organic EL panel 6. The terminal 61a is electrically connected by a joining member 7 such as an anisotropic conductive material.

  In the electro-optical device 1 according to the present embodiment, the mounting flexible wiring board 3 has a bent structure, but there is a structure in which the mounting flexible wiring board 3 is used without being bent.

  2 and 3 are simplified views of the main part of the embodiment of the mounting flexible wiring board according to the present invention. FIG. 2 is a schematic plan view, and FIG. 3 is a line AA in FIG. It is typical sectional drawing along.

  As shown in FIGS. 2 and 3, the mounting flexible wiring board 3 of the present embodiment has the upper side of FIG. 3 as a mounting side OS on which the driving IC 2 is mounted, and the lower side of FIG. The rear side RS is opposite to the mounting side OS.

  The mounting flexible wiring board 3 includes an insulating substrate 32 made of a flexible film having a thickness of about 12.5 to 25.0 μm made of an insulating material such as polyimide. A wiring pattern 31 is formed on the surface located on the mounting side OS, which is one surface of the insulating substrate 32. In a mounting area where the driving IC 2 of the wiring pattern 31 is mounted, an IC terminal to which an electrode (not shown) formed on the lower surface of the driving IC 2 on the circuit surface side shown in FIG. (Not shown) is formed. Further, on the lower side of FIG. 2, linear input terminals 31a that are electrically connected to connection terminals 41a formed on the surface of the circuit board 4 shown in FIG. 4 are arranged along the lower side. Further, on the upper side of FIG. 2, linear output terminals 31 b that are electrically connected to the panel terminals 61 a of the electro-optical panel 6 are arranged along the upper side. Furthermore, on both sides of the driving IC 2, heat radiation patterns 33 each having a widened portion wider than other wirings are disposed.

As the formation position of the heat radiation pattern 33, when the mounting flexible wiring board 3 is bent and used, the input terminal 31a and the output terminal 31b provided on the wiring pattern 31 formed on the insulating substrate 32 are used. That is, the opposing region between the input terminal forming region and the output terminal forming region on the mounting flexible wiring board 3 , and the region extending to the left and right sides of the opposing region in the left-right direction in FIG. It is preferable to be formed in the part.

  Of course, when the mounting flexible wiring board 3 is used without being bent, the heat radiation pattern 33 is formed on the wiring pattern 31 including both the left and right sides of the input terminal forming region and the left and right sides of the output terminal forming region and for driving. The formation position of the heat radiation pattern 33 can be set in a region excluding the mounting region of the IC 2.

  The heat radiation pattern 33 shown on the right side of FIG. 2 is directly connected to a dummy electrode provided in the driving IC 2 that does not contribute to electrical connection, that is, an electrode that does not participate in signal input / output. Further, the heat radiation pattern 33 shown on the left side of FIG. 2 is connected so as to extend to the ground wiring pattern or the power supply wiring pattern through which the largest current flows among the wiring patterns 31 connected to the electrodes of the driving IC 2. Is formed. Any one of these heat radiation patterns 33 may be used. Further, the heat radiation pattern 33 may be connected to a plurality of electrodes of the driving IC 2. Further, the heat radiation pattern 33 may be formed separately. Furthermore, examples of the shape of the heat radiation pattern 33 include a linear shape, a circular shape, a rectangular shape, a triangular shape, and a trapezoidal shape.

  The wiring pattern 31 and the heat radiation pattern 33 form a conductor pattern 34 of this embodiment. The conductor pattern 34 is formed, for example, by patterning a conductive layer made of a metal conductor (metal film) formed on the insulating substrate 32 by electroless plating or sputtering into a predetermined pattern by etching. That is, the wiring pattern 31 and the heat radiation pattern 33 are simultaneously formed of the same material.

  As the conductor pattern 34, a polyimide resin is applied to a metal foil such as copper or aluminum having a thickness of about 12 to 25 μm and cured, and then the metal foil is patterned into a predetermined pattern corresponding to the corresponding terminal by etching or the like. May be formed. Further, there is a forming method in which a conductive paste such as silver paste is formed by printing in a predetermined pattern.

  On the surface of the insulative substrate 32, a portion excluding a mounting region where the driving IC 2 is mounted, a region where the input terminal 31a is formed, a region where the output terminal 31b is formed, and a part of the heat radiation pattern 33 are polyimide resin or epoxy resin. The insulating protective film 35 is made of an insulating resin such as an acrylic resin. That is, the insulating protective film 35 is formed so as to partially cover the conductor pattern 34.

  Therefore, the exposed pattern 33 a that is not covered with the insulating protective film 35 is formed in the heat radiation pattern 33.

  Further, the size of the opening of the insulating protective film 35 formed in the mounting area of the driving IC 2 is formed larger than the outer size of the driving IC 2, and the state before mounting the driving IC 2 in this opening. The connection surface of the IC terminal provided on the wiring pattern 31 is exposed to the outside.

  A through hole 33b that penetrates the insulating substrate 32 in the thickness direction, more specifically, the heat dissipation pattern 33 and the insulating substrate 32 in the thickness direction, is formed at the center of the externally exposed portion 33a of the heat radiation pattern 33. Has been. This through hole 33b is arranged so as to overlap from above the island-shaped heat radiation land 42 formed on the surface of the circuit board 4 shown in FIG.

  The insulating substrate 32 has a connection opening 32a formed by removing a region immediately below a region where the input terminal 31a is formed, and the connection of the circuit substrate 4 disposed opposite to the input terminal 31a of the mounting flexible wiring board 3 is formed. Connection with the terminal 41a can be easily performed.

  The surface of the portion of the conductor pattern 34 that is not covered with the insulating protective film 35 is subjected to surface treatment for preventing corrosion, for example, tin plating or noble metal plating.

  The mounting flexible wiring board 3 may be configured such that the conductor pattern 34 and the insulating protective film 35 are provided on both the front and back surfaces of the insulating substrate 32.

  Further, the shape and number of the heat radiation pattern 33, the externally exposed portion 33a, and the through hole 33b can be arbitrarily set according to the design concept and the like.

  Since other configurations are the same as those of a conventionally known mounting flexible wiring board, detailed description and illustration thereof are omitted.

  FIG. 4 is a schematic plan view schematically showing a main part of an embodiment of the circuit board of the electro-optical device according to the invention.

  As shown in FIG. 4, the circuit board 4 of the present embodiment is exposed to the surface of the insulating substrate 42 to the outside for supplying at least power and control signals to the driving IC 2 of the mounting flexible wiring board 3. A wiring pattern 41 provided with the connection terminal 41a (only the connection terminal 41a is shown) and a pair of left and right island-shaped heat radiation lands 43 made of a conductive material provided in a region where the wiring pattern 41 is not formed are provided. is doing. Each of the heat radiation lands 43 is provided so as to be exposed to the outside outside a facing region of the mounting flexible wiring board 3 indicated by an imaginary line in FIG. 4 that does not face the mounting flexible wiring board 3. In each of the radiating lands 43, the regions indicated by the hatched regions in FIG. 4 that do not face the mounting flexible wiring board 3 are the land exposed portions 43a exposed to the outside. The heat radiation land 43 is formed so that a part thereof faces one end of the through hole 33 b of the mounting flexible wiring board 3. Note that one end of the through hole 33 b of the mounting flexible wiring board 3 may partially face the heat dissipation land 43.

  The wiring pattern 41 and the heat radiation land 43 are formed by, for example, patterning a conductive layer made of a metal conductor (metal film) formed on the substrate 42 by electroless plating or sputtering into a predetermined pattern by etching. ing. That is, it is preferable that the wiring pattern 41 and the heat radiation land 43 are simultaneously formed of the same material.

  As the wiring pattern 41 and the heat radiation land 43, a polyimide resin is applied to a metal foil such as copper or aluminum having a thickness of about 12 to 25 μm and cured, and then the metal foil is subjected to the corresponding terminal by etching or the like. You may form by patterning to a predetermined pattern. Further, there is a forming method in which a conductive paste such as silver paste is formed by printing in a predetermined pattern.

  Since at least the surfaces of the connection terminals 41a and the heat radiation lands 43 of the wiring pattern 41 are both exposed to the outside, surface treatment for preventing corrosion, for example, tin plating or noble metal plating is performed. Yes.

  The heat capacity necessary for cooling and radiating heat generated by the heat generated by the driving IC 2 in a short time by changing the type, surface area, and surface area of the land exposed portion 43a of the radiating land 43 provided on the circuit board 4. Can be easily set.

  Since other configurations are the same as those of a conventionally known circuit board, detailed description and illustration thereof are omitted.

  FIG. 5 is a schematic enlarged cross-sectional view schematically showing a main part of an embodiment of the circuit connection structure in the electro-optical device according to the invention.

As shown in FIG. 5, the mounting flexible wiring board 3 and the circuit board 4 in the electro-optical device 1 of this embodiment are the externally exposed portion 33 a of the heat radiation pattern 33 of the mounting flexible wiring board 3 and the circuit board 4. The heat dissipation land 43 is connected by the bonding material 8 through the through hole 33b. Incidentally, that as the bonding material 8, such as heat transfer guide is large metal or solder between each other and the outer exposed portion 33a of the heat dissipation pattern 33 and the heat dissipation land 43 can perform heat conduction rapidly and efficiently Preferred in terms. An anisotropic conductive material in which metal particles are mixed in a resin may be used.

  Other configurations are the same as the circuit connection structure between the mounting flexible wiring board and the circuit board in the conventionally known electro-optical device, and thus detailed description and illustration thereof are omitted.

  Next, the operation of the present embodiment having the above-described configuration will be described.

  According to the electro-optical device 1 of the present embodiment, when the temperature of the driving IC 2 rises due to heat generated by driving the driving IC 2, the thermal energy that causes the temperature rise of the driving IC 2 is connected to the electrodes of the driving IC 2. In addition to being transmitted to and absorbed by the heat dissipation pattern 33, heat is radiated into the atmosphere from the externally exposed portion 33 a not covered by the bonding material 8 and the surface of the bonding material 8. As a result, the driving IC 2 can be forcibly cooled.

  Note that by increasing the area of the externally exposed portion 33a of the heat dissipation pattern 33 and the size of the through hole 33b, the area used for cooling and heat dissipation of the heat dissipation pattern 33 can be easily increased.

  Further, even if the heat radiation pattern 33 rises in temperature due to absorption of heat from the driving IC 2, this heat flows from the external exposed portion 33 a provided in the heat radiation pattern 33 through the bonding material 8 to the circuit board 4. Since the heat is transmitted to the heat radiation land 43, the heat transmitted to the heat radiation pattern 33 is absorbed by the heat radiation land 43. As a result, the cooling function of the driving IC 2 can be ensured.

  Furthermore, even if the heat dissipation land 43 absorbs heat and the heat dissipation land 43 rises in temperature, this heat can be dissipated from the land exposed portion 43a of the heat dissipation land 43 to the atmosphere. It is possible to prevent the cooling rate from decreasing.

  Therefore, according to the mounting flexible wiring board 3 of the present embodiment, since the heat radiation pattern 33 is connected to the driving IC 2 as a semiconductor chip, the heat generated by the heat generation of the driving IC 2 can be absorbed. The absorbed heat can be radiated into the atmosphere from the externally exposed portion 33a of the heat radiation pattern 33. That is, the heat dissipation pattern 33 of the present embodiment can efficiently cool the heat generated by the driving IC 2.

  According to the mounting flexible wiring board 3 of the present embodiment, the through hole 33b that penetrates the insulating substrate 32 in the thickness direction is formed inside the external exposed portion 33a. It can be easily connected to the heat radiation land 43 of the circuit board 4 as the cooling member. That is, the through-hole 33b contributes to easily increasing the heat capacity of a member for cooling and radiating heat generated by the heat generated by the driving IC 2.

  According to the mounting flexible wiring board 3 of the present embodiment, since the heat radiation pattern 33 is formed between the input terminal 4 and the output terminal 6, as shown in FIG. Is used, the externally exposed portion 33a of the heat radiation pattern 33 by the bonding material 8 and the circuit board on the bent side of the connection portion between the input terminal 31a of the mounting flexible wiring board 3 and the connection terminal 41a of the circuit board 4 are used. 4 is disposed, the mechanical stress due to bending applied to the connection portion of the mounting flexible wiring board 3 to the input terminal 4 can be easily reduced. As a result, the connection reliability of the connection portion of the input terminal 4 of the mounting flexible wiring board 3 can be improved.

  According to the electro-optical device 1 of the present embodiment, the externally exposed portion 33a of the heat radiation pattern 33 of the mounting flexible wiring board 3 and the heat radiation land 43 of the circuit board 4 are connected to the bonding material 8 via the through hole 33b. Therefore, it is possible to efficiently conduct heat from the heat radiation pattern 33 to the heat radiation land 43 and to easily increase the capacity of the heat sink that cools and dissipates heat generated by the heat generated by the driving IC 2. Can be.

  According to the electro-optical device 1 of this embodiment, since the land for heat dissipation 43 is formed with the land exposed portion 43a that is exposed to the outside in a region that does not face the mounting flexible wiring board 3, Even if the heat dissipation land 43 absorbs heat and the temperature rises, this heat can be dissipated into the atmosphere via the land exposed portion 43a exposed to the outside, so that the heat dissipation rate is prevented from decreasing. can do.

  Therefore, according to the electro-optical device 1 of the present embodiment, the heat generated by the heat generated by the driving IC 2 can be quickly cooled. As a result, display quality can be easily improved. In addition, by adopting the present invention in an organic EL device, it contributes significantly to the recent demand for higher performance.

The present invention can be used not only for a mounting circuit board on which a driving IC is mounted, but also for a TCP type or COF type mounting flexible wiring board in which a heat generating electronic component is mounted on a flexible wiring board.

  The present invention is not limited to the above-described embodiments, and various modifications can be made as necessary.

FIG. 1 is a schematic structural diagram showing a simplified main part of an embodiment of an electro-optical device according to the invention. The typical top view which simplifies and shows the principal part of embodiment of the mounting flexible wiring board based on this invention Typical sectional drawing along the AA line of FIG. FIG. 2 is a schematic plan view schematically showing a main part of an embodiment of a circuit board of an electro-optical device according to the invention. FIG. 3 is a schematic enlarged cross-sectional view schematically showing a main part of an embodiment of a circuit connection structure in an electro-optical device according to the invention.

Explanation of symbols

1 Electro-optical device 2 Driving IC
DESCRIPTION OF SYMBOLS 3 Mounting flexible wiring board 31 Wiring pattern 31a Input terminal 31b Output terminal 32 Insulating board 32a Connection opening 33 Radiation pattern 33a External exposure part 33b Through-hole 34 Conductor pattern 35 Insulating protective film 4 Circuit board 41 Wiring pattern 41a Connection terminal 42 Substrate 43 Heat dissipation land 43a Land exposed part 6 Organic EL panel 8 Bonding material OS mounting side RS Back side

Claims (3)

A flexible insulating substrate; a semiconductor chip mounted on the insulating substrate; a wiring pattern connected to each of the plurality of electrodes of the semiconductor chip; and an insulating protective film covering the wiring pattern; Have
At least one of the wiring patterns is formed with an extended heat dissipation pattern that dissipates heat from the semiconductor chip,
In the heat radiation pattern, an externally exposed portion that is not covered with the insulating protective film is formed, and a through hole that penetrates the insulating substrate in the thickness direction is formed in the externally exposed portion. Mounting flexible wiring board;
An electro-optical panel connected to an output terminal of the mounting flexible wiring board;
A circuit board connected to an input terminal of the mounting flexible wiring board;
On the circuit board, a heat dissipation land made of a conductive material is formed, and an opposing region partially overlapping with the mounting flexible wiring board is formed,
In the opposing region, the heat dissipation land and the heat dissipation pattern of the mounting flexible wiring board are connected by a bonding material that conducts heat conduction quickly and efficiently through the through hole,
2. The electro-optical device according to claim 1, wherein a land exposed portion that extends to a region other than the opposing region and is exposed to the outside is formed in the heat dissipation land. The electro-optical device according to claim 1, wherein the heat dissipation pattern is connected to a power supply wiring pattern or a grounding wiring pattern among the wiring patterns .   The electro-optical device according to claim 1, wherein the electro-optical panel is an organic EL panel.