JP3151090B2 - Manufacturing method of liquid crystal display device with touch panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device with a touch panel used for a personal information tool having a handy communication function and, more particularly, a resistive film capable of inputting information with a pen or a finger. The present invention relates to a method for manufacturing a liquid crystal display device with a touch panel of a system.

[0002]

2. Description of the Related Art FIG. 6 shows a general structure of a liquid crystal display device with a touch panel of a resistive film type. Liquid crystal display panel 2
The touch panel 1 is integrated on the front side (upper side) of the touch panel 1. The touch panel 1 is a flexible electrode that is opposed to the fixed electrode 4 on the surface side of the fixed electrode 4 with a double-sided tape 7 or the like at an interval. And an electrode 3.

The fixed electrode 4 has a structure in which a transparent conductive film 9 such as ITO or SnO2 is formed on a surface of a hard substrate 12 made of glass or the like. The flexible electrode 3 is made of PE
A transparent conductive film 6 such as ITO is formed on the back surface of a substrate 5 made of a flexible film such as T (polyethylene terephthalate). In order to prevent the flexible electrode 3 from accidentally coming into contact with the fixed electrode 4, a dot spacer 8 made of resin is formed on the surface of the fixed electrode 4.

Further, electrode terminals 10 are formed on both ends of the fixed electrode 4 and the flexible electrode 3 with silver paste or the like in directions orthogonal to each other (see FIG. 8). The electrode terminals 10 formed on the fixed electrode 4 and the flexible electrode 3 are collectively wired at one place and connected to the flexible substrate 11.

The liquid crystal display panel 2 is joined to the lower part of the touch panel 1 having such a structure by a double-sided tape 13. The liquid crystal display panel 2 has an upper polarizing plate 14, an upper glass substrate 16, a lower glass substrate 16,
The lower polarizing plate 14 and the reflecting plate 19 are laminated. The periphery of the two glass substrates 16 is sealed by a spacer 17, and a liquid crystal material 18 as a display medium is sealed in the sealed space.

[0006] Such a resistive liquid crystal display device with a touch panel is used as follows.

As shown in FIG. 7, when the flexible electrode 3 of the touch panel 1 is pressed by a pen 20 or a finger from the front side of the liquid crystal display device, the flexible electrode 3 is locally bent and fixed electrode 4 is pressed.
Contact with. As shown in FIG. 8, the point of contact is a point for distributing the voltage applied to the electrode terminals 10 formed on both ends of the fixed electrode 4 and the flexible electrode 3, respectively. The voltage drop of the flexible electrode 3 is measured. Then, the voltage drop amount is subjected to signal processing by a signal processing circuit including an A / D converter,
The coordinates of the contact point are determined and are drawn on the liquid crystal display panel 2.

In a resistive liquid crystal display device with a touch panel, the touch panel 1 is
The light is reflected and absorbed by the touch panel 1 because it is disposed on the surface side of the touch panel 1. Therefore, there is a disadvantage that the contrast is reduced as compared with the case where the display of the liquid crystal display panel 2 is directly viewed.

As a liquid crystal display device with a touch panel which solves this drawback, a liquid crystal display device having the structure shown in FIG. 9 has been proposed. This liquid crystal display device uses a high contrast STN type reflective liquid crystal display panel as the liquid crystal display panel 2, and further comprises a polarizing plate (upper polarizing plate) 14 and a phase difference plate 21 constituting the reflective liquid crystal display panel. Are used as the flexible electrode substrate 5 of the touch panel 1.

The transparent conductive film 6 is deposited on the back surface of the phase difference plate 21.

[0011]

However, a trial production of such an improved liquid crystal display device with a touch panel revealed that there were the following problems.

The flexible electrode 3 does not easily contact the fixed electrode 4.

Poor writing durability.

When the transparent conductive film 6 is vapor-deposited on the phase difference plate 21, the characteristics thereof are deteriorated because the heat resistance of the phase difference plate 21 is insufficient.

Hereinafter, each problem will be specifically described. Generally, the power required for humans to write letters is 90-600 g,
It has been reported that the average weight is 200 g. From this relationship, in order to reliably input to the touch panel 1,
Even if the flexible electrode 3 of the touch panel 1 is pressed with 100 g, the flexible electrode 3 needs to be in contact with the fixed electrode 4. However, when the polarizing plate 14 and the retardation plate 21 are integrated into the flexible electrode substrate 5, a pressing force of 150 or more is required, so that the operability is poor and it is difficult to satisfy the user's demand. .

[0016] The writing durability is 200 to 300 g.
It is demanded that the shape does not collapse even if the character is written 100,000 times or more by pushing with the force of, but when the polarizing plate 14 and the phase difference plate 21 are integrated to form the flexible electrode substrate 5, Since the durability is insufficient, it has only about 10,000 times, and in this respect, the user cannot be satisfied.

On the other hand, in the process of manufacturing the touch panel 1, when a transparent conductive film material such as ITO is deposited on the retardation plate 21, the resistance is uniform and the sheet resistance is 300 to 400Ω.
When trying to obtain a transparent conductive film of Ohm / □, about 100 ° C
Must be applied to the phase difference plate 21. However, when the retardation plate 21 is given such a temperature due to the fact that polycarbonate is generally stretched and manufactured,
Due to variations in processing conditions, the phase difference partially shifts due to the effects of expansion and contraction due to heating. Therefore, the characteristic deterioration of the phase difference plate 21 becomes a problem.

The present invention solves the above-mentioned problems of the prior art, and an object of the present invention is to provide a liquid crystal display panel having a high-contrast structure using a constituent material for a flexible electrode substrate of a touch panel. It is an object of the present invention to provide a liquid crystal display device with a touch panel, in which a flexible electrode easily contacts a fixed electrode, has good writing durability, and is capable of preventing deterioration of characteristics due to formation of a transparent conductive film.

[0019]

Method for manufacturing a liquid crystal display device with a touch panel SUMMARY OF THE INVENTION The present invention is a manufacturing method of a liquid crystal display panel liquid crystal display device with a touch panel on the surface side of a resistive touch panel is integrated with , A pair of TAC
A transparent conductive film is formed on a front-side polarizing plate of a liquid crystal display panel having a polarizing layer interposed therebetween , and is used as a flexible electrode of the touch panel. It is configured to be placed separately from the board
Forming a transparent conductive film on one of the TACs in advance,
Forming the front-side polarizing plate with the polarizing layer interposed therebetween.
DOO is characterized by, the object is achieved.

[0020]

[0021]

[0022]

[0023]

As described above, the retardation plate is disposed separately from the flexible electrode (flexible electrode substrate) of the touch panel in which the transparent conductive film is formed on the front-side polarizing plate, that is, the two are not integrated. In this case, the thickness of the flexible electrode is reduced accordingly, and the flexibility is improved. When the flexibility is improved, cracking of the transparent conductive film formed on the surface of the flexible electrode is suppressed, and the writing durability of the flexible electrode is also improved.

Further, since the transparent conductive film is not formed on the phase difference plate, the characteristic deterioration of the phase difference plate is prevented.

(Principle of the Present Invention) The principle of the present invention will be described below. The inventor of the present invention solves the above-mentioned problem of the improved invention by reducing the thickness of the flexible electrode substrate to improve its flexibility. Side) I came to the conclusion that it is effective to separately arrange a flexible electrode substrate having a transparent conductive film formed on a polarizing plate and a retardation plate. That is, the thickness of the retardation plate is 50 μm, the thickness of the polarizing plate is 180 μm, and the thickness of the adhesive for bonding the two is 25 μm.
The total thickness is 255 μm.

On the other hand, when a flexible electrode having a transparent electrode formed on a polarizing plate is used, the thickness is 180 μm.
m. When we actually prototype such a thing and see it,
It was confirmed that input could be performed with a force of 0 g or less.

Investigation of the phenomenon of deterioration of writing durability shows that cracks are generated in the transparent conductive film formed on the flexible electrode substrate. It is considered that depending on the thickness of the electrode, as the thickness increases, the flexibility decreases, so that cracks are likely to occur. Then, when the thickness of the flexible electrode formed by forming a transparent conductive film on a polarizing plate was reduced, it was confirmed that the flexible electrode had a durability of 100,000 times or more.

On the other hand, when a transparent conductive film is formed on a polarizing plate, heat of about 100 ° C. is required. Further, in order to deposit a transparent conductive film, it is necessary to evacuate the deposition machine. In this case, gas is generated.

However, as shown in FIG. 5, the polarizing plate 14 has a polarizing layer 22 sandwiched between TAC (triacetyl cellulose) 23. If the transparent conductive film 6 is formed on this TAC film in advance, It was confirmed that a transparent conductive film could be formed on the deflection plate 14.

[0030]

The present invention will be described below with reference to examples.

(Embodiment 1) FIG. 1 shows Embodiment 1 of the present invention. The liquid crystal display device with a touch panel according to the first embodiment includes:
The configuration is such that a resistive touch panel 1 is attached to the surface of the liquid crystal display panel 2.

The liquid crystal display panel 2 has a high contrast S
A reflection type liquid crystal display panel of a TN type, wherein a spacer 1
Glass substrates 16 and 16 which are vertically arranged to face each other
And a liquid crystal material 18 sealed between the glass substrates 16, 16.
And

The lower (rear side) polarizing plate 14 is directly bonded to the lower surface of the lower glass substrate 16.
The reflection plate 19 is joined to the back surface of the. On the other hand, the upper (front surface) polarizing plate 14 and the phase difference plate 21 are incorporated in the touch panel 1 described later. In addition, electrodes and the like for driving the liquid crystal display panel 2 are not shown.

The touch panel 1 integrated on the surface side of the liquid crystal display panel 2 is fixed with the fixed electrode 4 bonded to the surface of the liquid crystal display panel 2 using a double-sided tape 13 or the like, and similarly with the double-sided tape 7 or the like. And a flexible electrode 3 disposed on the surface side of the electrode 4 so as to be opposed to the electrode 4 at an interval.

The fixed electrode 4 is made of a hard substrate 12 such as glass.
And a transparent conductive film 9 such as ITO or SnO2 formed on the surface of the substrate 12. On the surface of the transparent conductive film 9, a dot spacer 8 is formed of resin in order to prevent the flexible electrode 3 from accidentally coming into contact with the fixed electrode 4. On the other hand, a phase difference plate 21 constituting the liquid crystal display panel 2 is joined to the back surface of the substrate 12.

The flexible electrode 3 includes a flexible substrate 5 and a transparent conductive film 6 such as ITO formed on the back surface of the substrate 5. A polarizing plate 14 on the front side of the liquid crystal display panel 2 is used for the substrate 5.

At both ends of the fixed electrode 4 and the flexible electrode 3,
The electrode terminals 10 are formed of silver paste or the like in directions orthogonal to each other. The electrode terminals 10 formed on the fixed electrode 4 and the flexible electrode 3 are collectively wired at one place and connected to the flexible substrate 11.

In the liquid crystal display panel with the touch panel according to the first embodiment, the substrate 5 of the flexible electrode 3 in the touch panel 1
Can be made thinner than the above conventional example, and as a result,
The force required for input operation can be reduced. In addition, writing durability can be improved. Further, deterioration of display characteristics is also prevented.

(Embodiment 2) FIG. 2 shows Embodiment 2 of the present invention. In the second embodiment, the phase difference plate 21 constituting the liquid crystal display panel 2 is joined to the surface of the glass substrate 16 on the front side of the liquid crystal display panel 2. Other configurations are the same as those of the first embodiment. Also in the second embodiment, the substrate 5 of the flexible electrode 3 is used.
Since only the polarizing plate 14 is used and the retardation plate 21 is arranged separately from the substrate 5, the same effects as those of the first embodiment can be obtained.

(Embodiment 3) FIG. 3 shows Embodiment 3 of the present invention. The third embodiment has a configuration in which the phase difference plate 21 is bonded to the back surface of the glass substrate 16 on the back surface side of the liquid crystal display panel 2. Other configurations are the same as those of the first and second embodiments. Also in the third embodiment, since the polarizing plate 14 is used for the substrate 5 of the flexible electrode 3 and the retardation plate 21 is arranged separately from the substrate 5, the same effects as in the first and second embodiments can be obtained.

(Embodiment 4) FIG. 4 shows Embodiment 4 of the present invention. The fourth embodiment is different from the third embodiment in that the substrate 12 of the fixed electrode 4 in the touch panel 1 is omitted, and the front surface glass substrate 16 of the liquid crystal display panel 2 is used as the substrate 12. . Since other configurations are the same as those of the third embodiment, the writing property and the writing durability of the flexible electrode 3 and the display characteristics when the transparent conductive film 6 of the flexible electrode 3 is formed by vapor deposition are the same as those of the third embodiment. Has the same effect.

[0042]

The liquid crystal display device with a touch panel according to the present invention.
In the method of manufacturing , since the polarizing plate constituting the liquid crystal display panel is used for the flexible electrode substrate of the touch panel, the contrast is better as compared with the liquid crystal display device with the touch panel using the dedicated flexible electrode substrate. It is. In addition, the retardation plate is separated from the flexible electrode substrate, and the flexibility of the flexible electrode substrate is improved, so that the flexible electrode easily contacts the fixed electrode,
The writability is good, the transparent conductive film formed on the flexible electrode substrate is hardly cracked, and the writing durability of the flexible electrode is good. Further, the polarizing plate used for the substrate for a flexible electrode, unlike the retardation plate, can prevent deterioration of characteristics when a transparent conductive film is deposited. Therefore, when the transparent conductive film of the flexible electrode is formed by vapor deposition, deterioration of display characteristics can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display device with a touch panel according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a liquid crystal display device with a touch panel according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a liquid crystal display device with a touch panel according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a liquid crystal display device with a touch panel according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration of a polarizing plate.

FIG. 6 is a cross-sectional view showing a general configuration of a liquid crystal display device with a touch panel.

FIG. 7 is a cross-sectional view illustrating the operation principle of a liquid crystal display device with a touch panel.

FIG. 8 is a perspective view showing the operation principle of a liquid crystal display device with a touch panel.

FIG. 9 is a cross-sectional view illustrating a configuration of an improved conventional liquid crystal display device with a touch panel.

[Explanation of symbols]

 Reference Signs List 1 touch panel 2 liquid crystal display panel 3 flexible electrode 4 fixed electrode 5, 12 substrate 6, 9 transparent conductive film 14 polarizing plate 21 retardation plate

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G06F 3/03 320 G06F 3/033 350

Claims (1)

(57) [Claims] 1. A method of manufacturing a liquid crystal display device with a touch panel in which a resistive touch panel is integrated on the surface side of a liquid crystal display panel, wherein the liquid crystal display device comprises a polarizing layer sandwiched between a pair of TACs. to form a transparent conductive film on the surface side polarizing plate of the panel with use as the flexible electrode of the touch panel, configured to place the phase difference plate of the liquid crystal display panel is separated from the surface side polarizing plate
And a transparent conductive film is formed on one TAC in advance.
The front-side polarizing plate with the polarizing layer interposed therebetween by the TAC.
A method for manufacturing a liquid crystal display device with a touch panel , characterized by being formed .