JP2008009225A - Display device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device for preventing intrusion of air bubbles when laminating a transparent plate and a display element. <P>SOLUTION: The display device 100 in one embodiment of this invention is equipped with a display element 20, a touch panel 10 which is arranged opposite to the display element 20, a pressure sensitive adhesive sheet 14 which is arranged nearly over the entire surface of a display region 27 of the display element 20, and bonds the display element 20 and the touch panel 10, and electronic components 29 which are packaged on the surface on the counter transparent substrate side of the touch panel 10. The thickness of the pressure sensitive adhesive sheet 14 is ≥100 μm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display device and a manufacturing method thereof, and particularly relates to a display device including a transparent body bonded to one surface of a display element with an adhesive sheet and a manufacturing method thereof.

  In recent years, a display device using a transparent touch panel that is arranged on a display surface of a display element and that is directly pressed by a user's finger to perform an input operation such as a desired function selection has been put into practical use. In particular, when portability and operability are regarded as important, such as mobile terminals and bank terminals, touch panels are widely used instead of keyboards. Since the input method using the touch panel can be directly input by the user according to the display screen, it does not require knowledge or skill of a computer, and the operability is very good.

  Conventionally, such a transparent touch panel has been provided with a gap on the viewing side of a display element such as a liquid crystal display element. However, if there is an air layer between the touch panel and the display element, there is a problem that the reflection of light at these interfaces is large, and the visibility of the display element is lowered such as a reduction in contrast ratio.

Therefore, a configuration has been proposed in which a liquid adhesive is filled between the touch panel and the display element and then cured, or the touch panel and the display element are bonded by an adhesive sheet provided on the entire surface of the display element. Thereby, the visibility is improved by setting the air layer between the touch panel and the display element to be close to the refractive index of the glass. Patent Document 1 discloses a configuration in which a touch panel and a display element are bonded together by an acrylic transparent adhesive sheet provided on the entire viewing side of the display element.
JP 7-105781 A

  However, when a liquid adhesive is used, there is a problem that it is difficult to control the thickness of the adhesive layer between the display element and the touch panel. If a spacer material is added to control this thickness, white turbidity occurs and visibility deteriorates. Also, high pressure needs to be applied in order to align the height of the spacer material.

  Even in the case of using an adhesive sheet, it is necessary to apply a uniform pressure to the entire surface in order to prevent bubbles from being mixed. Usually, an electronic component such as a drive circuit is mounted on the side opposite to the display surface of the display element. Generally, in the process of bonding the touch panel and the display element, a jig having a recess corresponding to an electronic component mounted on the display element is used. By inserting the electronic component into the recess of the jig, the bonding surface of the display element is flattened and bonded to the touch panel.

  However, in the region where the electronic component is mounted, the recess is formed in the jig as described above, and the applied pressure is reduced. Thereby, there exists a problem that a bubble will arise between a touch panel and a display element. Since the mixed bubbles diffusely reflect light, the display quality is deteriorated.

  In order to solve this problem, it is conceivable to increase the pressure. However, when the pressure is increased, the display element and the touch panel are damaged, and the manufacturing yield is lowered. Such a problem occurs not only when the touch panel is bonded, but also when a cover used mainly for outdoor use is bonded to the display element.

  The present invention has been made against the background of such circumstances, and an object of the present invention is to provide a display device capable of preventing air bubbles from being mixed when a transparent plate and a display element are bonded together, and a method for manufacturing the same. The purpose is to provide.

  The display device according to the first aspect of the present invention includes a display element, a transparent body disposed opposite to the display element, and disposed on substantially the entire display area of the display element, the display element and the transparent body, And a component mounted on the surface of the display element on the side opposite to the transparent body or the surface of the transparent body on the side opposite to the display element, and the thickness of the pressure-sensitive adhesive sheet is 100 μm or more. It is what is. Thereby, it can prevent that a bubble mixes between a transparent body and a display element.

In the method for manufacturing a display device according to the second aspect of the present invention, a component is mounted on a display element or a transparent body, and the display element and the transparent body are arranged so that a surface on which the component is mounted becomes an outer surface. Adhering with an adhesive sheet having a thickness of 100 μm or more provided over substantially the entire display area of the display element, the transparent body and the display element are pressed and bonded together with a pressure of 0.75 kgf / cm ² or less. . Thereby, it is possible to prevent air bubbles from being mixed between the transparent body and the display element, and it is possible to suppress breakage of the display device.

  The manufacturing method of the display device according to the third aspect of the present invention is the above manufacturing method in which the transparent body and the display element are bonded together under reduced pressure. Thereby, it is possible to further prevent air bubbles from being mixed between the transparent body and the display element.

  ADVANTAGE OF THE INVENTION According to this invention, the display apparatus which can prevent mixing of a bubble when bonding a transparent body and a display element, and its manufacturing method can be provided.

  Hereinafter, embodiments to which the present invention can be applied will be described. The following description explains the embodiment of the present invention, and the present invention is not limited to the following embodiment.

Embodiment 1 FIG.
A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view illustrating an example of a configuration of a display device 100 including a transparent plate according to Embodiment 1. In the present embodiment, a capacitive touch panel 10 will be described as an example of a transparent body. The display device 100 according to the present embodiment includes a display element 20 and a touch panel 10 disposed on the viewing side of the display element 20. The touch panel 10 includes a cover 11, an adhesive layer 12, and an electrode substrate 13 including two transparent substrates in order from the viewing side. The display element 20 and the touch panel 10 are bonded together by the adhesive sheet 14. In the present embodiment, the display element 20 is, for example, a liquid crystal display element, and includes a polarizing plate 26, a counter substrate 24, a TFT array substrate 23, a polarizing plate 25, and a backlight unit 22 in order from the viewing side. Yes.

  First, the configuration of the display element 20 will be described. Here, an active matrix liquid crystal display element will be described as an example of a display element. Of course, the display element 20 is not limited to an active matrix liquid crystal display element, and may be a passive matrix liquid crystal display element. Furthermore, the display element 20 is not limited to a liquid crystal display element, and may be another display element such as an organic EL display element.

  The display element 20 performs image display based on the input display signal. The display element 20 includes a liquid crystal display panel 21 and a backlight unit 22. The liquid crystal display panel 21 has a configuration in which liquid crystal is sealed between the counter substrate 24 and the TFT array substrate 23. The counter substrate 24 and the TFT array substrate 23 are made of a transparent glass substrate, for example.

  A plurality of scanning lines are formed on the TFT array substrate 23 at regular intervals. A plurality of signal lines are formed at regular intervals on the scanning lines. The scanning line and the signal line are arranged so as to intersect with each other through an insulating film. A thin film transistor (TFT), which is a switching element, is disposed in the vicinity of the intersection of the scanning line and the signal line. A display signal is supplied from the signal line to the pixel electrode via the TFT. The pixel electrode is formed of a transparent conductive film such as ITO (Indium Tin Oxide), for example. The display area 27 of the liquid crystal display panel 21 is composed of a plurality of pixels arranged in a matrix. The display area 27 is usually formed in a rectangular shape. Further, the liquid crystal display panel 21 is provided with a frame area 28 provided so as to surround the display area 27.

  On the counter substrate 24, for example, a color filter including a black matrix (BM) and R, G, and B colored layers is formed. Each colored layer is formed between BMs and corresponds to a pixel. A counter electrode made of a transparent conductive film such as ITO is formed on the colored layer and BM. Such a TFT array substrate 23 and the counter substrate 24 are bonded to each other through a sealing material.

  Further, a drive circuit (not shown) is connected to the frame region 28 of the liquid crystal display panel 21. The drive circuit outputs various control signals, scan voltages, display voltages, and the like necessary for image display based on display signals input from the outside. The drive circuit may be mounted on the end of the TFT array substrate 23 by COG (Chip On Glass). The alignment state of the liquid crystal changes depending on the voltage between the pixel electrode and the counter electrode. Thereby, the amount of light transmitted through the liquid crystal display panel 21 is adjusted, and display can be performed.

  Polarizing plates 25 and 26 are attached to the outer surfaces of the TFT array substrate 23 and the counter substrate 24, respectively. Thereby, the liquid crystal display panel 21 is formed. Specifically, a polarizing plate 25 is provided on the surface of the TFT array substrate 22 on the non-viewing side. A polarizing plate 26 is bonded to the surface on the viewing side of the counter substrate 24. The polarizing plate 26 and the polarizing plate 25 each have an absorption axis in a predetermined direction. Therefore, the light passing through the polarizing plate 26 or the polarizing plate 25 becomes linearly polarized light. Thus, the display element 20 includes the liquid crystal display panel 21 having a general configuration.

  A backlight unit 22 is provided on the back side of the liquid crystal display panel 21. The backlight unit 22 irradiates the liquid crystal display panel 21 with planar light from the non-viewing side of the liquid crystal display panel 21. As the backlight unit 22, for example, a unit having a general configuration including a light source, a light guide plate, a prism sheet, and the like is used.

  Although not shown in FIG. 1, electronic components such as an inverter circuit for supplying power to the backlight unit and the detection circuit of the touch panel 10 are mounted on the non-viewing side of the display device 20. Yes. In the present embodiment, an electronic component is mounted on the non-viewing side of the backlight unit 22.

  Next, the configuration of the touch panel 10 disposed on the viewing side of the display element 20 will be described. The touch panel 10 is, for example, a capacitive touch panel. As shown in FIG. 1, the touch panel 10 includes a cover 11, an adhesive layer 12, an electrode substrate 13 made of two transparent substrates, a first FPC 15, a second FPC 16, and the like.

  Here, the configuration of the electrode substrate 13 will be described with reference to FIGS. FIG. 2 is a diagram showing the configuration of the electrode substrate 13. FIG. 3 is a plan view showing an electrode pattern formed on the outer surface of one transparent substrate 131 of the electrode substrate 13. FIG. 4 is a plan view showing an electrode pattern formed on the outer surface of the other transparent substrate 132 of the electrode substrate 13.

  As shown in FIGS. 2 to 4, the electrode substrate 13 has two transparent substrates 131 and 132 made of glass or the like. The two transparent substrates 131 and 132 are bonded via a sealing material. As shown in FIG. 3, a plurality of first electrodes 31 extending in parallel to each other in the vertical direction are formed on the surface on the viewing side of the transparent substrate 131. In addition, as shown in FIG. 4, a plurality of second electrodes 32 extending in parallel with each other in the horizontal direction are formed on the surface of the transparent substrate 132 on the non-viewing side. Therefore, as shown in FIG. 2, the first electrode 31 and the second electrode 32 are formed on the electrode substrate 13 so as to intersect each other. That is, the first electrode 31 and the second electrode 32 are arranged so as to be orthogonal to each other with the transparent substrates 131 and 132 interposed therebetween.

  A region where the first electrode 31 and the second electrode 32 are formed is an effective area 33. This effective area 33 corresponds to the display area 27 of the display element 20. Therefore, the effective area 33 is formed in the same rectangular shape as the display area 27 of the display element 20. A frame-shaped area outside the effective area 33 is a non-effective area 34. The first electrode 31 and the second electrode 32 formed in the effective area 33 are made of, for example, ITO. Further, the conductive film is not limited to ITO, but may be other transparent conductive films such as IZO and ITZO. Therefore, the effective area 33 of the touch panel 10 is transparent, and the content displayed on the display element 20 can be confirmed via the touch panel 10 from the viewing side. Therefore, in the present embodiment, touch panel 10 is a transparent body.

  As shown in FIG. 3, a plurality of first electrodes 31 are arranged at regular intervals on the surface of the transparent substrate 131 on the viewing side. A first connection wiring 35 connected to the first electrode 31 is formed in the ineffective area 34. The first connection wiring 35 is connected to the first electrode 31. In FIG. 3, six first connection wirings 35 are formed in order to be connected to the six first electrodes 31. In addition, the number of the 1st electrode 31 and the 1st connection wiring 35 is not restricted to this.

  The first connection wiring 35 is connected to the first electrode 31 at the lower end of the effective area 33. The first connection wiring 35 extends from the lower end of the effective area 33 to the lower end of the transparent substrate 131. For example, the first connection wiring 35 is formed of the same transparent conductive film as the first electrode 31. That is, the first connection wiring 35 extends from the first electrode 31. Although not shown here, a first FPC 15 connected to the first connection wiring 35 is provided at the lower end of the transparent substrate 37.

  On the other hand, as shown in FIG. 4, a plurality of second electrodes 32 are arranged at regular intervals on the surface of the transparent substrate 132 on the non-viewing side. The non-effective area 34 is provided with a second connection wiring 36 connected to the second electrode 32. The second connection wiring 36 is connected to the second electrode 32. In FIG. 4, six second connection wirings 36 are formed to be connected to the six second electrodes 32. In addition, the number of the 2nd electrode 32 and the 2nd connection wiring 36 is not restricted to this.

  The second connection wiring 36 is connected to the second electrode 32 at the right end or the left end of the effective area 33. The second connection wiring 36 extends from the right end or the left end of the effective area 33 to the lower end of the transparent substrate 132. The second connection wiring 36 has a laminated structure of a transparent conductive film and a metal film. For example, the second connection wiring 36 can be formed by the same transparent conductive film as the second electrode 32 and a metal film formed thereon. Of course, the configuration of the second connection wiring 35 is not limited to this. Although not shown here, a second FPC 16 connected to the second connection wiring 36 is provided at the lower end of the transparent substrate 132.

  As shown in FIG. 1, a cover 11 is attached to the viewing side of the electrode substrate 13 with an adhesive layer 12. The cover 11 is made of, for example, a plastic plate having a thickness of 0.8 mm. An adhesive layer 12 is provided between the cover 11 and the electrode substrate 13. Note that the surface of the cover 11 serves as an operation surface with which a position indicator such as a finger contacts during operation. The adhesive layer 12 is, for example, a double-sided adhesive sheet or an adhesive, and bonds the cover 11 and the electrode substrate 13 together. The adhesive layer 12 is formed of, for example, a transparent resin material having a thickness of 175 μm. The adhesive layer 12 is disposed on substantially the entire display area 27.

  A first FPC (Flexible Printed Circuit) 15 and a second FPC 16 are connected to one end of the electrode substrate 13. The first FPC 15 is attached to the surface on the viewing side of the electrode substrate 13, and the second FPC 16 is attached to the surface on the non-viewing side of the electrode substrate 13. Signals are input / output to / from the electrode substrate 13 by the first FPC 15 and the second FPC 16.

  The touch panel 10 thus formed is attached to the viewing side of the display element 20, that is, the display surface side, with an adhesive sheet 14. As the adhesive sheet 14, a double-sided adhesive sheet made of acrylic resin or the like is used. In addition, as the adhesive sheet 14, what has an adhesive layer on both surfaces of the base material which consists of PET (poly (ethylene terephthalate)) resin etc. can also be used. The adhesive sheet 14 is formed of a transparent resin material having a thickness of 100 μm or more. In this Embodiment, the adhesive sheet 14 is formed in the thickness of 125 micrometers, for example. Further, the adhesive sheet 14 is disposed on substantially the entire display area 27.

  As described above, by setting the thickness of the adhesive layer 14 to 100 μm or more, it is possible to prevent air bubbles from being mixed between the touch panel 10 and the display element 20. For this reason, it is possible to suppress deterioration in display quality due to the mixed bubbles. Even if bubbles are mixed between the touch panel 10 and the display element 20, the bubbles can be dispersed in the adhesive layer 14 as small bubbles in the adhesive sheet 14. For this reason, the deterioration of display quality can be suppressed. Moreover, it is preferable that the thickness of the adhesive sheet 14 is 0.5 mm or less, More preferably, it is 0.3 mm or less. Thereby, the brightness | luminance fall resulting from the reflection loss of the light of the adhesive sheet 14, etc. can be suppressed.

  Here, the operation of the touch panel 10 will be described. A fixed capacitor is formed at each intersection of the first electrode 31 and the second electrode 32. When the user brings a finger or the like close to the first electrode 31 in the effective area 33 from above the cover 11, the parasitic capacitance between the fingertip and the first electrode 31 and the parasitic capacitance of the human body are connected in parallel to the fixed capacitance. The Rukoto. As a result, the value of the combined capacitance changes, and the voltage across the fixed capacitance changes. By detecting this change in voltage with a detection circuit, the contacted position can be detected. When the user approaches an arbitrary position in the effective area 33 while the display element 20 is performing a predetermined display, processing based on the display is executed.

  Here, with reference to FIG.5 and FIG.6, the manufacturing method of the display apparatus 100 which concerns on this Embodiment is demonstrated. FIG. 5 is a flowchart for explaining a method of manufacturing display device 100 according to the present embodiment. Moreover, FIG. 6 is a figure which shows the state before bonding the display element 20 and the touch panel 10 of the display apparatus 100 which concern on this Embodiment. In FIG. 6, the same components as those in FIG. 1 are denoted by the same reference numerals.

  First, as shown in FIG. 5, a transparent conductive film is formed on each of the transparent substrates 131 and 132, and the transparent conductive film is patterned to provide a first electrode 31, a second electrode 32, and the like. The substrates 131 and 132 are bonded to each other with a sealant with the first electrode 31 and the second electrode 32 facing outward to form the electrode substrate 13 (step S101). As a method for forming the transparent conductive film, a DC sputtering method or the like can be used. Thereafter, in each of the transparent substrates 131 and 132, the first FPC 15 is connected to the first connection wiring 35, and the second FPC 16 is connected to the second connection wiring 36 (step S102). The first FPC 15 and the second FPC 16 and the electrode substrate 13 can be connected by thermocompression bonding using an ACF (Anisotropic Conductive Film) or the like. Then, the cover 11 made of glass or the like is attached to the electrode substrate 13 by the adhesive layer 12 (step S103). Thereby, the touch panel 10 is completed.

  And the touch panel 10 and the display element 20 are bonded together by the adhesive sheet 14 whose thickness is 100 micrometers or more (step S104). In the present embodiment, the touch panel 10 and the display element 20 are bonded together by pressing the touch panel 10 against the display element 20 using a pressure bonding tool under reduced pressure. Therefore, the touch panel 10 and the display element 20 are disposed in the vacuum chamber and bonded together. Thereby, it can suppress more effectively that a bubble mixes between the touch panel 10 and the display element 20. FIG.

  First, the pressure-sensitive adhesive sheet 14 having a thickness of 100 μm or more is formed on substantially the entire display area 27 on the display surface side of the display element 20. Then, as shown in FIG. 6, the display surface of the display element 20 and the electrode substrate 13 of the touch panel 10 are disposed to face each other in the vacuum chamber. As shown in FIG. 6, an electronic component 29 is mounted on the back side of the display element 20. Therefore, although not shown here, the jig for fixing and holding the display element 20 has a relief hole corresponding to the mounting portion of the electronic component 29. By housing the electronic component 29 in the escape hole formed in the jig, the display element 20 can be kept flat, and the touch panel 10 can be attached with high accuracy.

Then, the display area 27 of the display element 20 and the effective area 33 of the touch panel 10 are aligned, and the display element 20 and the touch panel 10 are bonded by the adhesive sheet 14. At this time, the pressure applied by the crimping tool is 0.75 kgf / cm ² or less. As described above, the pressure-sensitive adhesive sheet 14 has a thickness of 100 μm or more. For this reason, in the region where the electronic component is mounted, the concave portion is formed in the jig as described above, and the applied pressure is reduced. However, depending on the thickness of the adhesive sheet 14, the gap between the touch panel and the display element is reduced. It is possible to suppress the generation of air bubbles. In addition, it is possible to suppress a decrease in display quality due to the generation of bubbles.

  Moreover, since the applied pressure can be reduced, breakage of the display element 20 and the touch panel 10 such as cracking and chipping can be suppressed, and the manufacturing yield can be improved. Thereafter, as shown in FIG. 5, the operation and appearance are inspected (step S115), and the display device 100 is completed.

  As described above, when the display element 20 having unevenness such as an electronic component on the back surface side of the adhesive surface and the touch panel 10 are bonded together, it is possible to manufacture a good display element 100 that does not generate bubbles. . Moreover, since it can paste | paste with a low pressure, generation | occurrence | production of defects, such as a crack and a chip, can be suppressed and manufacturing yield can be improved.

  In this embodiment, the touch panel is attached to the display surface side of the display element. However, the present invention is not limited to this. For example, in a display element mainly used for outdoor use, the present invention can also be applied when attaching a scratch-resistant transparent cover or the like. Further, the present invention can also be applied when a transparent cover or the like is attached to the liquid crystal display panel 21 instead of the display element 20. Moreover, although the cover 11 and the electrode substrate 13 are bonded as the touch panel, only the electrode substrate 13 may be attached to the display element 20. Furthermore, an ITO heater may be used as the transparent body.

Example.
Examples of the present invention will be described below. In this example, a glass substrate was pressed against a 3.5 inch liquid crystal display panel in a vacuum chamber and bonded using an adhesive sheet. As the pressure-sensitive adhesive sheet 14, CS9621 (25 μm) containing no Nitto Denko base material and No. 5603 (30 μm), no. 5606 (60 μm), no. 5608 (80 μm), no. 5610 (100 μm), no. 5612 (120 μm), no. 5615 (150 μm) was used.

  Moreover, as the adhesive sheet 14, 8141 (25 μm), 8142 (50 μm), 8161 (25 μm), F-9473 PC (255 μm), 467 MP (50 μm), 468 MP (125 μm) 9483 without a substrate made by Sumitomo 3M are included. (125 μm) was used.

As a result, regardless of whether the base material is contained or not, when the pressure-sensitive adhesive sheet 14 having a thickness of 50 μm or less is used, bubbles are generated even when a pressure of 0.8 kgf / cm ² or more is applied. . Moreover, when the pressure-sensitive adhesive sheet 14 having a thickness of 50 to 100 μm is used, the generation of bubbles can be suppressed by applying a pressure of 0.75 kgf / cm ² or more, but there is a concern that the substrate may be damaged. On the other hand, when the pressure-sensitive adhesive sheet 14 having a thickness of 100 μm or more was used, it was possible to suppress the generation of bubbles with a relatively low pressure of about 0.25 kgf / cm ² , and to perform favorable pasting.

It is a top view which shows the structure of the display apparatus which concerns on embodiment. It is a top view which shows the structure of the electrode substrate which concerns on embodiment. It is a figure which shows the structure of the electrode of the one surface of one transparent substrate which concerns on embodiment. It is a figure which shows the structure of the electrode of the one surface of the other transparent substrate which concerns on embodiment. It is a flowchart explaining the manufacturing method of the display apparatus which concerns on embodiment. It is a figure which shows the state before bonding the display element and input device of the display apparatus which concern on embodiment.

Explanation of symbols

10 Touch Panel 11 Cover 12 Adhesive Layer 13 Electrode Substrate 14 Adhesive Layer 15 First FPC
16 Second FPC
20 display element 21 liquid crystal display panel 22 backlight unit 23 TFT array substrate 24 counter substrate 25 polarizing plate 26 polarizing plate 27 display region 28 frame region 29 electronic component 31 first electrode 32 second electrode 33 effective area 34 non-effective area 35 first 1 connection wiring 36 2nd connection wiring 38 Insulating layer 131 Transparent substrate 132 Transparent substrate

Claims (3)

A display element;
A transparent body disposed opposite to the display element;
An adhesive sheet that is disposed on substantially the entire display area of the display element, and bonds the display element and the transparent body;
Components mounted on the surface of the display element on the side opposite to the transparent body or the surface of the transparent body on the side opposite to the display element;
A display device comprising:
The thickness of the said adhesive sheet is a display apparatus which is 100 micrometers or more. Mount the parts on the display element or transparent body,
Adhering the display element and the transparent body with a pressure-sensitive adhesive sheet having a thickness of 100 μm or more provided on substantially the entire display area of the display element, so that the surface on which the component is mounted is an outer surface;
A method for manufacturing a display device, in which the transparent body and the display element are pressed and bonded together with a pressure of 0.75 kgf / cm ² or less.   The method for manufacturing a display device according to claim 2, wherein the transparent body and the display element are bonded together under reduced pressure.

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