JP2000330126A - Liquid crystal panel and method of mounting driving circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal panel having excellent display quality in which a warpage of substrate is prevented even when a driving circuits are directly mounted on a substrate, and leaking of light in the display screen is prevented even when a narrow frame structure is formed, and to provide a method for mounting driving circuits. SOLUTION: The liquid crystal panel 1a is produced by laminating a pair of substrates 2a and 3a to form a liquid crystal cell in such a manner that lead electrodes from the inner electrodes of the liquid crystal cell are exposed on one substrate 2a in the peripheral part of the liquid crystal cell, then disposing driving circuits 4 with anisotropic conductive films interposed on one substrate 2a, and directly mounting the driving circuits 4 on the substrate 2a by heating and pressurizing the upper part of the driving circuits 4. In this production process, notches 8 are formed on the sides of the mounting positions of the driving circuits on one substrate 2a so that the thermal expansion of the substrate 2a is almost same as the thermal expansion of the driving circuits 4, and then the driving circuits 4 are fixed by heat to the substrate 2a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal cell in which a pair of substrates are bonded to each other, and an extraction electrode from an internal electrode of the liquid crystal cell is exposed on one of the substrates and directly driven to the one substrate. The present invention relates to a liquid crystal panel on which a circuit is mounted and a method for mounting a drive circuit.

[0002]

FIG. 3 is a perspective view of a conventional liquid crystal panel, and FIG.
Denotes a device for mounting a drive circuit on a liquid crystal panel. In a conventional liquid crystal panel 1b, a first glass substrate 2b on which a transparent electrode is formed and a second glass substrate 3b are bonded so that their respective electrode surfaces face each other to form a liquid crystal cell. An extraction electrode from the internal electrode is exposed on one of the substrates, here, the first glass substrate 2b on the outer periphery,
The driving circuit 4 for driving the liquid crystal panel 1b is directly mounted on the extraction electrode of the first glass substrate 2b.

[0003] The drive circuit 4 is mounted on the first glass substrate 2b by using a heated crimping tool.
othropic Conductive Film, hereinafter referred to as “ACF”. )
COG (Ch) that mounts the drive circuit 4 on a glass substrate through the
ip On Glass). As shown in FIG. 4A, the heating tool includes a pedestal 7b made of quartz and a thermocompression bonding section 6, and when the component mounting position of the first glass substrate 2b is placed on the pedestal 7b made of quartz, The drive circuit 4 is arranged on the lead electrode of the one glass substrate 2 b via the ACF 5.

Then, the drive circuit 4 is heated from above the drive circuit 4 by pressing the drive circuit 4 toward the first glass substrate 2b by the thermocompression bonding section 6. ACF5 is 14 for the thermocompression bonding part 6
ACF5 is heated and pressurized so as to have a temperature of 0 ° C. or more to melt ACF5. After the heating and pressurization are completed, the drive circuit 4 is opened to the atmosphere and returned to room temperature, the ACF 5 is cured, and the drive circuit 4 is fixed to the first glass substrate 2b.

[0005]

In the COG mounting method as described above, the driving circuit 4 and the ACF 5 are heated during the thermocompression bonding by the thermocompression bonding unit 5, but the pedestal of the thermally insulating quartz pedestal 7b is removed. Since it is used, the first glass substrate 2b is cooled by the quartz pedestal 7b.

Accordingly, the driving circuit 4 and the first glass substrate 2
4B, a temperature gradient as shown in FIG. 4B occurs, and a difference occurs in the average temperature between the drive circuit 4 and the first glass substrate 2b. Further, in the first glass substrate 2b, the direction of heat transmission is not only in the thickness direction but also in the horizontal direction of the glass, so that the temperature difference between the drive circuit 4 and the first glass substrate 2b further increases.

Therefore, when heating is performed by the thermocompression bonding section 6, the expansion of the drive circuit 4 due to the thermal expansion becomes larger than the expansion of the first glass substrate 2b due to the thermal expansion. When the temperature of the first glass substrate 2b returns to room temperature, warpage occurs in the first glass substrate 2b at this contact portion. Such a warp is not a problem if the portion where the drive circuit 4 is mounted is separated from the screen display portion.
When the screen display portion and the mounting portion of the drive circuit 4 become closer to each other due to a narrow frame, the screen has a problem that the screen becomes lighted due to the warpage.

The present invention solves the above-mentioned problems, and even when a drive circuit is directly mounted on a substrate, there is no warpage of the substrate and excellent display quality without light leakage on a display screen even with a narrow frame structure. It is an object to provide a mounting method of a liquid crystal panel and a driving circuit.

[0009]

The liquid crystal panel of the present invention comprises:
The thermal expansion of the substrate is controlled by setting the shape of the outer peripheral portion of the substrate to a special shape. According to the present invention, it is possible to eliminate the difference in the coefficient of thermal expansion between the substrate and the driving circuit, and to obtain a liquid crystal panel with good display quality without light leakage on the screen due to warpage of the substrate.

The method of mounting a drive circuit according to the present invention is characterized in that the amount of thermal deformation of the substrate due to heating and the amount of thermal deformation of the drive circuit are controlled to be the same. According to this invention,
The above liquid crystal panel can be easily realized.

[0011]

According to a first aspect of the present invention, there is provided a liquid crystal panel, wherein an extraction electrode from an internal electrode of the liquid crystal cell is exposed on one of the substrates at an outer peripheral portion of the liquid crystal cell where a pair of substrates are bonded.
In a liquid crystal panel in which a driving circuit is directly mounted on the one substrate, a cutout is formed on a side of a mounting position of the driving circuit on the one substrate to control thermal expansion of the substrate.

According to a second aspect of the present invention, there is provided a method of mounting a drive circuit, wherein an extraction electrode from an internal electrode of a liquid crystal cell is exposed on one of the substrates at an outer peripheral portion of the liquid crystal cell to which a pair of substrates are bonded.
A drive circuit is mounted on the substrate via the anisotropic conductive film on the one substrate, and when manufacturing a liquid crystal panel in which the drive circuit is directly mounted on the substrate by heating and pressing from above the drive circuit, A notch is formed on the side of the mounting position of the drive circuit of the one substrate so that the thermal expansion of the one substrate is substantially the same as the thermal expansion of the drive circuit, and then the drive circuit is thermally mounted on the substrate. It is characterized by being fixed.

According to a third aspect of the present invention, in the second aspect, the driving circuit mounted on the substrate is heated and pressed via the anisotropic conductive film to directly mount the driving circuit on the substrate. In this case, the mounting position of the drive circuit is simultaneously heated from below. Hereinafter, a liquid crystal panel of the present invention and a method of mounting a drive circuit on the liquid crystal panel will be described based on specific embodiments. 3 and 4 showing the above-mentioned conventional example are denoted by the same reference numerals and described.

FIG. 1 shows a finished shape of a liquid crystal panel of the present invention, and FIG. 2 shows an apparatus for mounting a drive circuit on the liquid crystal panel. In the liquid crystal panel 1a of this embodiment, a first glass substrate 2a on which a transparent electrode is formed and a second glass substrate 3a are bonded so that their respective electrode surfaces face each other to form a liquid crystal cell. On the outer periphery of the liquid crystal cell, an extraction electrode from the internal electrode is exposed on one substrate, here, the first glass substrate 2a.
The driving circuit 4 for driving the liquid crystal panel 1a is directly mounted on the extraction electrode a.

On the outer peripheral portion of the first glass substrate 2a, a mounting portion 9 for mounting the drive circuit 4 and a side of the mounting portion 9 for controlling thermal expansion of the substrate, specifically, a mounting portion. Notch portions 8 formed on both sides of the portion 9 are formed. FIG. 2 illustrates a process of mounting the drive circuit 4 on the first glass substrate 2a on which the mounting portion 9 and the cutout portion 8 are formed.
Shown in

As shown in FIG. 2A, the driving circuit 4 is mounted on the mounting section 9 using a crimping tool having substantially the same configuration as the COG mounting method shown in FIG. Is different in that a heating pedestal 7a having a heating means is used instead of the quartz pedestal 7b. As mentioned above,
First substrate 2a on which mounting portion 9 and notch portion 8 are formed
Is mounted such that the mounting portion 9 and the heating pedestal 7a are in contact with each other, and the drive circuit 4 is arranged on the lead electrode of the first substrate 2a via the ACF 5.

The drive circuit 4 is heated from the upper portion of the drive circuit 4 by pressing the drive circuit 4 toward the mounting portion 9 by the thermocompression bonding portion 6, and the lower portion of the mounting portion 9 is heated by the heating pedestal 7 a to remove the ACF 5. Let melt. At this time, as shown in FIG. 2 (b), for example, as shown in FIG.
From the side of a, heating is performed at a temperature T2 (where T2 <T1).
It is necessary to perform heating so that the heating temperature is equal to or higher than the temperature at which the ACF 5 sandwiched between the drive circuit 4 and the mounting section 9 cures.

As described above, the mounting portion 9 has the cutouts 8 on both sides, and the expansion in the horizontal direction is smaller than the expansion in the vertical direction due to heating. When the temperatures T1 and T2 are controlled so as to satisfy the following expression, the expansion of the drive circuit 4 and the expansion of the first glass substrate 2a can be made to match. L × 3.0 × 10 ⁻⁶ × (T1−23) = L × 4.6 × 10 ⁻⁶ × [{(220 + T2) /
2} −23] T2 = (1.30 × T1) −204 Room temperature: 23 ° C. L: Drive circuit width 3.0 × 10 ⁻⁶ : Linear expansion coefficient of liquid crystal glass substrate 4.6 × 10 ⁻⁶ : Drive circuit (silicon) line Expansion coefficient After heating and pressurization are completed, the circuit is opened to the atmosphere and returned to room temperature, the ACF 5 is cured, and the drive circuit 4 is fixed to the mounting portion 9 of the first glass substrate 2b.

With such a configuration, the portion which was conventionally cooled by the pedestal without transmitting the heat and the thermal expansion was suppressed is no longer suppressed by the thermal expansion. Further, by forming the mounting portion 9 on the outer peripheral portion, the heat transmission distance in the lateral direction of the glass substrate 2b is shortened, and the temperature difference can be reduced. Further, when the drive circuit 4 is mounted on the substrate, the mounting position of the drive circuit is simultaneously heated from below by the heating pedestal 7a, so that the temperature gradient between the drive circuit 4 and the mounting section 9 can be reduced. .

In the above embodiment, the notch 8
Are formed on both sides of the mounting portion 9, but the present invention is not limited to this, and the first glass substrate 2a is formed such that the thermal expansion thereof is substantially the same as the thermal expansion of the drive circuit 4. As long as it is possible, one side of the mounting portion 9 may be used, and the shape of the cutout portion is not limited.

[0021]

As described above, according to the liquid crystal panel of the present invention, the extraction electrode from the internal electrode of the liquid crystal cell is exposed on one of the substrates at the outer periphery of the liquid crystal cell on which the pair of substrates are bonded. In a liquid crystal panel in which a drive circuit is directly mounted on a substrate, the one substrate is formed with a cutout on a side of a mounting position of the drive circuit to control the thermal expansion of the substrate, so that the substrate and the drive circuit A difference in coefficient of thermal expansion can be eliminated, and a liquid crystal panel with good display quality without light leakage on the screen due to warpage of the substrate can be obtained.

Further, according to the driving circuit mounting method of the present invention, an extraction electrode from an internal electrode of the liquid crystal cell is exposed on one of the substrates at an outer peripheral portion of the liquid crystal cell on which the pair of substrates are bonded. A drive circuit is mounted on the substrate via an anisotropic conductive film on the substrate, and when manufacturing a liquid crystal panel in which the drive circuit is directly mounted on the substrate by heating and pressing from above the drive circuit, the one of the one A notch is formed on the side of the mounting position of the drive circuit of the one substrate so that the thermal expansion of the substrate is substantially the same as the thermal expansion of the drive circuit, and then the drive circuit is thermally fixed to the substrate. Thus, the above-described liquid crystal panel can be easily realized.

[Brief description of the drawings]

FIG. 1 is a perspective view of a liquid crystal panel in an embodiment.

FIG. 2 is a diagram showing a mounting process of a driving circuit in the embodiment.

FIG. 3 is a perspective view of a conventional liquid crystal panel.

FIG. 4 is a diagram showing a mounting process of a conventional drive circuit.

[Explanation of symbols]

 1a Liquid crystal panel 2a First substrate 3a Second substrate 4 Drive circuit 5 ACF 6 Heat bonding part 7a Heating pedestal 8 Notch

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H092 GA48 GA49 GA51 GA57 GA60 HA26 MA32 MA35 NA01 NA07 NA15 NA16 NA25 NA27 NA29 PA06 5G435 AA00 AA12 BB12 EE30 EE33 EE35 EE37 EE42 KK05 KK10

Claims (3)

[Claims] 1. A liquid crystal panel in which a lead electrode from an internal electrode of a liquid crystal cell is exposed on one of the substrates at an outer peripheral portion of the liquid crystal cell to which a pair of substrates are bonded, and a driving circuit is directly mounted on the one of the substrates. 3. The liquid crystal panel according to claim 1, wherein the one substrate has a cutout formed on a side of a mounting position of a driving circuit to control thermal expansion of the substrate. 2. An extraction electrode from an internal electrode of a liquid crystal cell is exposed on an outer peripheral portion of a liquid crystal cell in which a pair of substrates are bonded to each other, and is driven on the one substrate via an anisotropic conductive film. When manufacturing a liquid crystal panel in which a circuit is mounted on a substrate and the drive circuit is directly mounted on the substrate by heating and pressing from above the drive circuit, the thermal expansion of the one substrate is substantially equal to the thermal expansion of the drive circuit. A method of mounting a drive circuit, wherein a cutout is formed on a side of a mounting position of the drive circuit on the one substrate so as to have the same thermal expansion, and then the drive circuit is thermally fixed to the substrate. 3. When a drive circuit mounted on a substrate is heated and pressurized via an anisotropic conductive film to directly mount the drive circuit on the substrate, the mounting position of the drive circuit is simultaneously heated from below. A method for mounting the drive circuit according to claim 2.