KR20210123617A - Compression bonding device - Google Patents

Abstract

According to exemplary embodiments of the present invention, the compression device comprises: a compression unit which applies the pressure, in a direction that a touch sensor and a circuit board overlap as a compression direction, to a portion where the touch sensor and the circuit board overlap; and a protective cover which is disposed to cover at least a portion of the optical film in the same direction as the compression direction. The compression device can prevent damage to the optical film formed on the touch sensor and realize ACF bonding between the touch sensor and the circuit board.

Description

Compression device {COMPRESSION BONDING DEVICE}

The present invention relates to a crimping device. More specifically, it relates to a compression device for bonding anisotropic conductive film (ACF).

With the recent development of the information society, demands for the display field are also presented in various forms. For example, various flat panel display devices having characteristics such as reduction in thickness, weight reduction, and low power consumption are being studied.

In addition, a touch panel or a touch sensor, which is an input device that is attached to the display device so that a user's command can be input by selecting instructions displayed on the screen with a human hand or an object, is combined with the display device to provide an image display function and Electronic devices in which an information input function is implemented are being developed.

On the other hand, manufacturers of display devices are making various attempts to implement a narrow bezel that forms a smaller bezel defined as the width of the non-display area outside the display area. The narrow bezel technology is a technology for increasing the size of an effective screen on which an image is displayed on a display panel of the same size relatively by reducing the bezel on which an image is not displayed at the edge of the display panel.

Accordingly, in the touch sensor coupled to the display device, a circuit board such as a flexible circuit board (FPCB) is disposed in a limited non-display area to be electrically connected to the touch sensor integrated circuit (IC) chip, and the touch sensor and the circuit board are ACF It can be attached through (Anisotropic Conductive Film) or ACP (Anisotropic Conductive Paste).

Anisotropic Conductive Film (ACF) is a type of thermosetting resin, and due to its characteristics, the FPCB and the touch sensor can be adhered to each other only when a certain temperature, pressure, and time are applied. In this case, thermal deformation and damage to the optical film formed on the touch sensor may occur due to the characteristics of the ACF bonding process performed under high temperature and high pressure conditions.

For example, Korean Patent Laid-Open Publication No. 10-1994-0020155 discloses a bonding device using an anisotropic conductive film, but has a limit in preventing damage to the optical film formed on the touch sensor.

Korean Patent Publication No. 10-1994-0020155

One object of the present invention is to prevent damage to the optical film formed on the touch sensor and to provide a compression device capable of implementing ACF bonding of the touch sensor and the circuit board.

1. A touch sensor stage on which a touch sensor having an optical film is mounted, a circuit board stage on which a circuit board bonded to the touch sensor is mounted, the overlapping direction on a portion where the touch sensor and the circuit board overlap in a compression direction Compression unit for applying pressure, and a compression device comprising a protective cover disposed to cover at least a portion of the optical film in the same direction as the compression direction.

2. The compression apparatus according to the above 1, wherein the overlapping portion of the touch sensor and the circuit board is defined as a pad area of the touch sensor.

3. In the above 2, the pad region and the circuit board are overlapped with an anisotropic conductive film (ACF) interposed therebetween, and the pressing part applies heat and pressure from the top of the circuit board to apply heat and pressure to the anisotropic conductive film. A crimping device that heat-seals the

4. The pressing device according to the above 2, wherein the pad area and the protective cover do not overlap in the pressing direction.

5. The compression device according to the above 2, wherein the protective cover is arranged to cover an area adjacent to the pad area of the optical film.

6. The compression device according to 2 above, further comprising a quartz to which the pad region is mounted.

7. The compression device according to 1 above, wherein the protective cover includes a metal.

8. The above 1, wherein the protective cover further comprises a cooling unit for maintaining the temperature of the optical film, the compression device.

9. The compression apparatus according to the above 2, further comprising a light source for irradiating light to the pad area.

10. The compression apparatus of 9 above, further comprising an imaging unit configured to detect an alignment state of the touch sensor and the circuit board by detecting the light transmitted through the pad area.

11. The pressing device according to the above 1, wherein the touch sensor stage and the circuit board stage have a step difference.

12. Mounting the touch sensor with the optical film formed thereon to the touch sensor stage, disposing a protective cover to cover at least a portion of the upper surface of the optical film, mounting the circuit board to the circuit board stage, an anisotropic conductive film between A step of overlapping the touch sensor and the circuit board by providing an (Anisotropic Conductive Film, ACF), and applying heat and pressure in a direction in which the touch sensor and the circuit board are overlapped from the upper part of the circuit board to the touch sensor and and bonding the circuit board.

13. The method of the above 12, further comprising the step of irradiating light to an area where the touch sensor and the circuit board overlap, and aligning the touch sensor and the circuit board by sensing the light. how it works.

14. The method of the above 12, further comprising the step of separating the protective cover from the touch sensor after the bonding step, the operating method of the pressing device.

15. The method of operation of the compression device according to the above 12, wherein the protective cover is arranged to cover a portion adjacent to an area where the touch sensor and the circuit board overlap.

16. The method of 12 above, further comprising the step of driving a cooling unit attached to the protective cover to lower the temperature of the optical film.

Compression apparatus according to exemplary embodiments of the present invention includes a pressing unit that applies pressure to a portion where a touch sensor and a circuit board overlap in a pressing direction in a pressing direction, and at least the optical film in the same direction as the pressing direction. ACF bonding of the touch sensor and the circuit board on which the optical film is formed, including a protective cover disposed to cover a portion, may be performed.

During the anisotropic conductive film bonding process for electrically connecting the touch sensor and the circuit board, it is possible to prevent damage that may occur to the optical film adjacent to the high-temperature compression part. For example, it is possible to prevent lateral deterioration, bubble formation, and whitening of the optical film formed on the touch sensor.

According to exemplary embodiments, the protective cover disposed to cover the optical film on the upper surface of the touch sensor on which the optical film is formed may include a metal. By disposing a protective cover including a metal material having high thermal conductivity on the upper surface of the optical film, it is possible to prevent damage to the side of the optical film due to heat and pressure applied adjacent to the optical film.

1 is a schematic side view showing a compression device according to exemplary embodiments.
Fig. 2 is a schematic side view showing a compression device according to some exemplary embodiments.
3 and 4 are photographs of a touch sensor-circuit board assembly subjected to anisotropic conductive film bonding using a compression device of a comparative example.

Exemplary embodiments of the present invention include a protective cover disposed to cover at least a portion of an optical film, and provide a compression device and a driving method thereof for performing anisotropic conductive film bonding of a touch sensor and a circuit board on which the optical film is formed . In this case, it is possible to prevent damage and deterioration of the optical film formed on the touch sensor.

Hereinafter, with reference to the drawings, embodiments of the present invention will be described in more detail. However, the following drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical spirit of the present invention together with the above-described content of the present invention, so the present invention is described in such drawings It should not be construed as being limited only to the matters.

1 is a schematic side view showing a compression device according to exemplary embodiments of the present invention.

Referring to FIG. 1 , the compression device may include a touch sensor stage 100 , a circuit board stage 110 , a compression unit 170 , and a protective cover 150 .

The touch sensor stage 100 may load the touch sensor 200 to be bonded to the anisotropic conductive film (ACF) 270 . ACF bonding with the circuit board may be performed by fixing and mounting the touch sensor 200 on the touch sensor stage 100 .

For example, the touch sensor 200 may include a substrate and a conductive sensing electrode formed on the substrate. The sensing electrode may include, for example, a metal, a metal alloy, a transparent conductive oxide, and a stacked structure of a transparent conductive oxide and a metal, but is not limited thereto. The touch sensor 200 of various structures may be manufactured according to the arrangement of the sensing electrode, for example, the sensing electrode to be driven by a mutual-capacitance method or a self-capacitance method. can be arranged.

An optical film 250 may be formed on the touch sensor 200 , and the touch sensor 200 on which the optical film is formed may be inserted into the display device. For example, the optical film 250 may include a single layer of a polarizer or a laminated polarizing plate in which a transparent protective film is bonded to one surface of the polarizer.

In exemplary embodiments, a portion of the touch sensor 200 may be laminated in the order of the touch sensor 200 , the anisotropic conductive film 270 and the circuit board 290 , and the touch sensor 200 and the circuit board The portion where 290 overlaps may be defined as the pad region 220 of the touch sensor 200 . For example, the pad region 220 may include a pad electrically connected to the sensing electrode of the touch sensor 200 .

The pad region 220 may be a terminal part connected toward one end of the substrate of the touch sensor 200 , and may be provided as a bonding region for electrically connecting the sensing electrode and the driving integrated circuit (IC). For example, the pad region 220 may be electrically connected to a driving integrated circuit (IC) chip through a circuit connection structure such as a flexible printed circuit board (FPCB).

In example embodiments, the pad region 220 of the touch sensor 200 may not overlap the optical film 250 formed on the touch sensor 200 . In this case, the compression unit 170 may apply pressure only to the pad region 220 and may not directly apply heat or pressure to the optical film 250 . However, the pad region 220 and the optical film 250 may be close to each other in order to realize a narrow bezel that forms a smaller width of the non-display region, and the compression unit 170 is the optical film 250 . ) and a region close to about 100 μm or less, heat and pressure can be applied. In this case, the side surface of the optical film 250 may be damaged and deteriorated by the high-temperature compression unit 170 , but the compression device according to exemplary embodiments of the present invention covers all or part of the optical film 250 . The protective cover 150 may be provided to prevent bubble formation and whitening of the optical film 250 .

The circuit board stage 110 may load a circuit board 290 on which an anisotropic conductive film (ACF) 270 bonding is to be performed. For example, the circuit board 290 may include a circuit member such as a flexible printed circuit board (FPCB). In this case, ACF bonding with the touch sensor 200 may be performed by fixing and mounting the circuit board 290 on the circuit board stage 110 .

In example embodiments, the touch sensor stage 100 and the circuit board stage 110 may have a step difference, and the circuit board stage 110 may be positioned higher than the touch sensor stage 100 . For example, the touch sensor stage 100 for loading the touch sensor 200 and the circuit board stage 110 for loading the circuit board 290 are stepped by the height of the touch sensor 200 and the anisotropic conductive film 270 . can have

The anisotropic conductive film 270 serves to electrically connect the target circuit board 290 and the touch sensor 200, and includes an adhesive layer including an insulating resin component and a plurality of conductive layers dispersed in the adhesive layer. It may include a ball (conductive ball). Specifically, during heating and pressurization for bonding, the resin in the adhesive layer flows while sealing and filling the gap between the electrodes (or electrode patterns) formed on the circuit board 290 or the touch sensor 200, and at the same time, the conductive ball connects with the electrode It can be filled between the electrodes while making contact. The conductive balls filled between the electrodes may be distributed while being broken to some extent by pressure, and accordingly, the anisotropic conductive film 270 may electrically connect the circuit board 290 and the touch sensor 200 .

The type of the adhesive material used for the adhesive layer of the anisotropic conductive film 270 is not particularly limited. For example, the adhesive layer may include an acrylic resin, an epoxy resin, or a urethane resin. In addition, the conductive ball may have a spherical, elliptical, or polygonal shape, and the conductive ball may include polymer particles forming a central portion of the shape and a metal component surrounding the resin. The type of polymer particles is not particularly limited, but may be, for example, an acrylic resin. The metal component is also not particularly limited, but, for example, gold (Au) or nickel (Ni) may be used.

The compression unit 170 may apply heat and pressure to the overlapping portion of the touch sensor 200 and the circuit board 290 as the pressing direction. For example, the touch sensor 200, the anisotropic conductive film 270, and the circuit board 290 may be laminated in this order, and the same direction as the lamination direction may be the pressing direction of the pressing unit 170. .

In example embodiments, the compression unit may perform ACF bonding by applying heat and pressure on the upper portion of the circuit board 290 . The compression unit 170 may apply high temperature/high pressure to the pad region 220 to generate thermal fusion of the anisotropic conductive film 270 and electrically connect the touch sensor 200 and the circuit board 290 . For example, the compression unit 170 may include a hot bar that rises to about 100 to 240° C., and may apply heat and pressure for about 10 to 20 seconds.

The protective cover 150 may be disposed to cover at least a portion of the optical film 250 in the same direction as the compression direction of the compression unit 170 . For example, the protective cover 150 may be disposed to cover only the optical film 250 without overlapping the pad region 220 in the compression direction. Accordingly, damage to the optical film 250 may be prevented without affecting the process in which the compression unit 170 presses the pad region 220 .

In example embodiments, the protective cover 150 may be disposed to cover an area adjacent to the pad area 220 of the optical film 250 . For example, the pad region 220 and the optical film 250 may be formed close to each other without overlapping in the compression direction. In this case, the protective cover 150 may be disposed to cover the area adjacent to the pad area 220 of the optical film 250 , or may be disposed to cover only the area adjacent to the pad area 220 . Accordingly, it is possible to prevent the optical film 250 in the area adjacent to the pad area 220 from being damaged by the high-temperature compression unit 170 that applies pressure to the pad area 220 , and whitening of the optical film 250 can be prevented. Development and bubble formation can be prevented.

In example embodiments, the protective cover 150 may be disposed on at least a portion of the upper surface of the optical film 250 , and may be disposed only on the optical film 250 formed on the touch sensor 200 . In this case, the protective cover 150 may be disposed not to cover the pad area 220 . Therefore, it is possible to effectively prevent damage and lateral deterioration that may occur in the optical film 250 adjacent to the high-temperature compression unit 170 during the high temperature and high pressure ACF bonding process.

In exemplary embodiments, the protective cover 150 may be separated from the touch sensor 200 after performing the ACF bonding process, and a magnetic detachment method may be used to facilitate detachment of the protective cover 150 . A method of detaching the protective cover may be used without limitation as long as it does not physically damage the optical film 250 .

In example embodiments, the protective cover 150 may include a metal. For example, the metal is silver (Ag), gold (Au), copper (Cu), aluminum (Al), iron (Fe), platinum (Pt), chromium (Cr), tungsten (W), manganese (Mn) ), cobalt (Co), nickel (Ni), zinc (Zn), and may include at least one of tin (Sn). Therefore, due to the metal material having high thermal conductivity, heat transferred to the optical film 250 during the ACF bonding process can be released more quickly, and the defect rate caused by damage to the optical film 250 can be reduced.

Fig. 2 is a schematic side view showing a compression device according to some exemplary embodiments.

Referring to FIG. 2 , the compression device of the present invention may further include at least one of a quartz 320 , a cooling unit 160 , a light source unit 350 , and an imaging unit 370 .

The quartz 320 may load the pad area 220 of the touch sensor 200 . For example, the pad region 220 , the anisotropic conductive film 270 , and the portion stacked in this order of the circuit board 290 may be fixed and mounted on the quartz 320 to perform ACF bonding.

The pad region 220 and the circuit board 290 of the touch sensor 200 may be overlapped with an anisotropic conductive film 270 disposed therebetween, and heat and pressure are applied to the overlapping portion to form the pad region 220 and the circuit. The substrate 290 may be bonded. In this case, alignment between the pads branched from each of the sensing electrodes of the touch sensor 200 and a circuit connection structure such as a flexible printed circuit board (FPCB), and an anisotropic conductive film 270 aligned may be pressed to electrically connect the pads and the FPCB. Therefore, by loading the pad area on the transparent quartz 320, a light or a camera is installed in the compression device to align the pad area 220, the anisotropic conductive film 270, and the circuit board 290. .

In addition, since the quartz 320 has a low thermal conductivity, it is possible to reduce the loss of heat provided to the anisotropic conductive film 270 by the compression unit 170 and to easily maintain the temperature for ACF bonding. The properties of quartz are not limited, and quartz used in the technical field of the present invention may be used without limitation.

According to some exemplary embodiments, the protective cover 150 may further include a cooling unit 160 for maintaining the temperature of the optical film 250 . For example, the cooling unit 160 may be attached to all or part of the protective cover 150 , and may be functionally inserted into the protective cover 150 . The cooling unit 160 may be used without limitation as long as it is a system for lowering the temperature, for example, a water cooling system cooling using a liquid medium or an air cooling system cooling using a gas medium may be used. Therefore, it is possible to effectively maintain the temperature of the optical film 250 in the ACF bonding process accompanied by a high temperature condition.

According to example embodiments, the pad region 220 and the circuit board 290 may further include a light source unit 350 for irradiating light to the overlapped portion. The light source unit 350 may be positioned at the lower or upper portion of the quartz 320 without limitation, as long as it can irradiate light to the portion where the touch sensor 200, the anisotropic conductive film 270, and the circuit board 290 are stacked. have. In addition, it may further include an imaging unit 370 for detecting the light passing through the stacked portion. By installing a light and/or a camera in the compression device, it is possible to monitor the progress of the related process in more detail. Accordingly, it is possible to efficiently align the pads of the sensing electrode and the FPCB, and increase the yield of the ACF bonding process.

Hereinafter, preferred embodiments are presented to help the understanding of the present invention, but these examples are merely illustrative of the present invention and do not limit the appended claims, and are within the scope and spirit of the present invention. It is obvious to those skilled in the art that various changes and modifications are possible, and it is natural that such variations and modifications fall within the scope of the appended claims.

Example

An ACF bonding process was performed using the touch sensors and FPCBs of Sample Nos. #1 to #5.

As a compression device, as shown in FIG. 2, a protective cover applied on a polarizing plate was used, and specifically, a hot bar (bonding tip) that rose to about 145° C. and applied a pressure of about 2.1 kg was used, and the Heat and pressure were applied for 15 seconds by pressing the bonding tip on the upper surface.

When the bonding tip was pressed, the distance between the bonding tip and the polarizing plate was about 100 μm.

The results of performing ACF bonding on Sample Nos. #1 to #5, respectively, are shown in Table 1 below.

sample #One #2 #3 #4 #5 picture

result Good Good Good Good Good

comparative example

An ACF bonding process was performed using the touch sensors and FPCBs of Sample Nos. #1 to #5.

The compression device does not include a protective cover, and specifically, a hot bar (bonding tip) that rises to about 145° C. and applies a pressure of about 2.1 kg was used, and the bonding tip was pressed on the upper surface of the FPCB to heat and pressure was applied

When the bonding tip was pressed, the distance between the bonding tip and the polarizing plate was about 100 μm.

The results of performing ACF bonding on Sample Nos. #1 to #5, respectively, are shown in Table 2 below.

sample #One #2 #3 #4 #5 picture

result Good error Good error Good

Referring to Tables 1 and 2, when a compression device including a protective cover is used, it is shown that no defects occur in the polarizing plate in Sample Nos. #1 to #5. On the other hand, when a compression device not including a protective cover was used, polarizing plate bubbles were generated for samples #2 and #4.

3 and 4 are photographs of a touch sensor-FPBC assembly on which ACF bonding is performed using a compression device of a comparative example. Specifically, FIG. 3 shows that bubbles are generated in the polarizing plate formed on the touch sensor. 4 shows that the whitening phenomenon occurred in the polarizing plate formed on the touch sensor. For example, depending on the position tolerance of the compression unit 170 and the optical film 250 and the physical properties of the optical film 250, weakly polarizing plate bubbles may occur, and in severe cases, whitening accompanied by air bubbles may occur.

100: touch sensor stage 110: circuit board stage
150: protective cover 160: cooling unit
170: crimping unit 200: touch sensor
220: pad area 250: optical film
270: anisotropic conductive film 290: circuit board
320: quartz 350: light source unit
370: imaging unit

Claims (16)

a touch sensor stage on which a touch sensor having an optical film formed thereon is mounted;
a circuit board stage on which a circuit board bonded to the touch sensor is mounted;
a pressing unit applying pressure to a portion where the touch sensor and the circuit board overlap with the overlapping direction as a pressing direction; and
and a protective cover disposed to cover at least a portion of the optical film in the same direction as the compression direction.
The compression apparatus of claim 1 , wherein a portion where the touch sensor and the circuit board overlap is defined as a pad area of the touch sensor.
The method according to claim 2, The pad region and the circuit board overlap with an anisotropic conductive film (Anisotropic Conductive Film, ACF) therebetween,
The compression unit applies heat and pressure on the upper portion of the circuit board to heat-seal the anisotropic conductive film.
The compression device according to claim 2, wherein the pad area and the protective cover do not overlap in the compression direction.
The compression device according to claim 2, wherein the protective cover is disposed to cover an area adjacent to the pad area of the optical film.
The compression apparatus according to claim 2, further comprising a quartz to which the pad region is mounted.
The compression device according to claim 1, wherein the protective cover comprises a metal.
The compression device according to claim 1, wherein the protective cover further comprises a cooling unit for maintaining the temperature of the optical film.
The method according to claim 2, Compression apparatus further comprising a light source for irradiating light to the pad area.
The compression apparatus of claim 9 , further comprising an imaging unit configured to detect an alignment state of the touch sensor and the circuit board by detecting the light that has passed through the pad area.
The compression apparatus according to claim 1, wherein the touch sensor stage and the circuit board stage have a step difference.
Mounting the optical film-formed touch sensor to the touch sensor stage;
disposing a protective cover to cover at least a portion of the upper surface of the optical film;
mounting the circuit board to the circuit board stage;
overlapping the touch sensor and the circuit board by providing an anisotropic conductive film (ACF) therebetween; and
and bonding the touch sensor and the circuit board by applying heat and pressure in a direction in which the touch sensor and the circuit board overlap on the circuit board.
13. The method of claim 12,
irradiating light to an area where the touch sensor and the circuit board overlap; and
Sensing the light further comprising the step of aligning the touch sensor and the circuit board, the operating method of the pressing device.
The method of claim 12 , further comprising separating the protective cover from the touch sensor after the bonding step.
The method of claim 12 , wherein the protective cover is disposed to cover a portion adjacent to an area where the touch sensor and the circuit board overlap.
The method of claim 12 , further comprising: lowering the temperature of the optical film by driving a cooling unit attached to the protective cover.

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