JP2001324707A - Touch panel for liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch panel for a liquid crystal display and a transparent touch panel to be used as mounted on an LCD such that visibility of the LCD on the touch panel surface is improved and a hardly visible image with specific colors can be prevented without decreasing the brightness of the screen on the LCD. SOLUTION: The transparent touch panel is to be mounted on a liquid crystal display and is combined with a polarizing plate to control the peak wavelength in the transmittance of the touch panel, and thereby, colors of the liquid crystal and the touch panel are matched with each other without changes in the colors of the liquid crystal display even when the touch panel is mounted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a touch panel which is combined with a surface of a liquid crystal display (LCD) and functions as an input device based on a display on the LCD. More specifically, the present invention relates to a touch panel that does not change the LCD display quality such as optical reflection, glare, and brightness when combined with an LCD.

[0002]

2. Description of the Related Art Conventionally, a touch panel used in combination with the front of such an LCD is disclosed in
No. 2,788,392, JP-A-2-130501, etc., a non-glare sheet in which the surface of a plastic film is embossed or the like to prevent reflection on the surface by external light, or a refractive index In consideration of this, an antireflection sheet or the like in which an antireflection layer and a polymer film are formed on the front and back surfaces of a plastic film has been proposed. Further, JP-A-5-127822 and the like disclose that in a touch panel disposed on a surface of an LCD or the like, the surface reflection is reduced and the antiglare property, contrast, and display accuracy are improved. It is assumed that a retardation plate, a polarizing plate and a non-glare-treated transparent film are sequentially laminated, and reflection of outside light is prevented by a non-glare treatment sheet, and light incident on the touch panel and reflected on the LCD surface is incident on the phase difference plate. Because it is out of phase with light,
It is stated that the reflected light having a shifted phase is cut by a polarizing plate. Japanese Patent Application Laid-Open No. 10-48625 discloses a touch panel that prevents reflection of external light on a transparent conductive film and allows the light of an LCD to pass through with little loss. Described is a touch panel in which a first quarter-wave plate, two transparent conductive films facing each other via a spacer, a second quarter-wave plate, and a polarizing plate are arranged in this order from the LCD side. Have been. As such a touch panel, an optical type, an ultrasonic type, a resistive type, a capacitive type, and the like are generally used. Among them, recently, in combination with a liquid crystal display, an ultrasonic type, a resistive type Expressions and optical methods are often used, and are becoming more and more useful.

Such a polarizing plate is used on the front and back surfaces of an LCD to improve the antiglare property of the LCD.
It has long been disclosed that it can be used in combination with a wave plate. The display color of the LCD monitor has been developed with one goal of the display screen quality of the CRT monitor.
The color temperature of the white color of the CRT is about 6500K, and the color temperature (white display color) differs for each liquid crystal maker, and the screen tends to be bluish or yellowish. However, a bluish color that looks whiter is preferred because white tends to look bright even if the actual luminance is low when white. However, most of the polarizers currently on the market are yellowish, more prominent in the case of a high polarization type, and more noticeable as a color change when used in combination with an LCD. ing. When a touch panel on which such a polarizing film is laminated is mounted on an LCD, unlike the original color of the LCD, the surface of the touch panel appears to be colored, thereby deteriorating the LCD screen quality or making it difficult to see clearly. Is seen.

[0004]

In view of the above circumstances, the inventors of the present invention have proposed a transparent touch panel mounted on an LCD and used to reflect not only the reflection on the touch panel surface but also the reflection from the interface of each layer such as a transparent substrate. This has led to the completion of a liquid crystal display touch panel that improves the visibility of the LCD and does not reduce the brightness of the LCD screen, but gives a distinctive color tone and makes it difficult to view the image.

[0005]

A first feature is a transparent touch panel mounted on a liquid crystal display,
When using a polarizing plate to improve low reflection, anti-glare properties and contrast, adjust the peak wavelength of the light transmittance of the touch panel so that the color of the liquid crystal display does not change even when the touch panel is mounted. It is characterized in that the colors are matched to reduce the change in the colors of the LCD.

A second feature is that the substrate is provided with at least one set of three or more layers of a multilayer film structure.
By having a multilayer structure of three or more layers, it is possible to achieve a film configuration that brings the peak wavelength of light transmittance to a lower wavelength side, and does not change the original color tone of the LCD in a state where the polarizing plate is combined. No change, little reflection,
A touch panel with excellent anti-glare properties and contrast can be obtained. For example, there are many commonly used polarizing plates having a yellow tint, and a touch panel using such a polarizing plate is mounted on an LCD, and when the color tint of the LCD is slightly yellowish, The multilayer structure is laminated and the combination of the thicknesses is adjusted to adjust the peak wavelength of the touch panel to bluish and the peak wavelength to 430 to 550 nm.

A third feature is that a polarizing plate is combined. The polarizing plate is composed of a single polarizing plate or a combination of a polarizing plate and a λ / 4 retardation plate. And a polarizing plate is laminated. By combining the linearly polarized light by the polarizing plate and the circularly polarized light by the phase difference plate, it is possible to cut the light transmitted through the polarizing plate at each interface. Further, by laminating the phase difference plates on the upper and lower sides of the touch panel, the incident light from the LCD to the touch panel can pass through the touch panel without being cut by the phase difference plate and the polarizing plate, so that the display screen is made darker. Less.

A fourth feature is that the touch panel is a resistive touch panel, and has at least one set of three or more multilayer conductive films including a resistive film.
In a resistive touch panel, since a transparent conductive film layer is formed on a transparent substrate, the adhesiveness between the substrate and the conductive film layer is further improved, and further, the sliding resistance of the substrate surface is improved.
Although various film configurations are often used, a multilayer conductive film of three or more layers including a resistance film is used. In the resistive film type, it is possible to use a plastic film for the substrate,
It is ideal for recent portable devices that are lightweight, small in thickness, light, thin and short.

A fifth feature is that the touch panel is an ultrasonic touch panel and has at least one set of three or more multi-layer films on the upper or lower side of the transparent substrate. Although an ultrasonic touch panel does not require a conductive film configuration, it can be suitably used without a color tone even when combined with a polarizing plate for an LCD by providing a multilayer film configuration of three or more layers.

A sixth feature is that the touch panel is an optical touch panel, and has at least one set of three or more multilayer films on the upper or lower side of the transparent substrate. Even though the optical touch panel does not require a conductive film configuration, it is necessary to use a transparent substrate for mounting on an LCD. Therefore, it is useful to laminate a polarizing plate to prevent reflection, and a multilayer structure of three or more layers is required. The provision of the film configuration makes it possible to prevent the appearance of a color tone.

A seventh feature is that the touch panel is a transparent capacitive touch panel, wherein one resistive film is provided on the surface of the transparent substrate and at least one set of three or more multilayer films is provided on the back surface of the transparent substrate. With this configuration, a display screen with good reflection and no reflection and no hue can be obtained.

An eighth feature is that the multilayer structure of three or more layers is a metal oxide layer having a high refractive index of at least 1.7 to 2.3 from the surface side of the substrate, 1.43 to 1.7. , And a multi-layer structure of three or more layers including a metal oxide layer having a low refractive index and a high refractive index layer. By using a combination of high and low refractive indices, it is possible to prevent the light transmittance from lowering, so that the screen can be prevented from becoming darker.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a main cross-sectional view showing a state where a liquid crystal touch panel 1 having a typical configuration of the present invention is combined with an LCD 2. The touch panel 1 is a transparent touch panel, and can be applied to any type of touch panel such as an ultrasonic type, a resistive type, an optical type, and a capacitive type that uses a transparent substrate.
The CD 2 can be applied to a reflective type or a transmissive type without any problem. However, a transmissive LCD is preferable in consideration of the brightness of the screen. Further, the LCD has a λ / 4 retardation plate 9 and a polarizing plate 1.
It is also preferable to use the polarizing plate 11 and the polarizing plate 11 as needed, and it is possible to employ it appropriately.

As shown in FIG. 1, a liquid crystal touch panel 1
Λ / 4 on at least one surface (upper surface in FIG. 1)
By laminating the retardation plate 4 and the polarizing plate 5, reflected light due to room light or external light reflected on the screen of the touch panel 1, reflected light from the inside or lower surface of the touch panel 1, the surface of the LCD, etc., is cut, A beautiful bright screen that is easy to see without reflection and has excellent anti-glare properties. λ / 4 retardation plate 4,
The polarizing plate 5 may be laminated on either the upper surface or the lower surface of the touch panel 1.

The multilayer structure of at least three or more layers includes an undercoat layer on the other surface of the transparent substrate 3 (the lower surface in FIG. 1) or between the HC layer and the transparent substrate 3 in order from the substrate side. 6, a multilayer structure including an intermediate layer 7 and a metal oxide layer 8 is laminated. The undercoat layer 6 is a metal oxide layer having a refractive index of 1.7 to 2.3 as a high refractive index layer, and may be an insulator. For example, ITO (indium-tin oxide), indium oxide, tin oxide with antimony, tin oxide with fluorine, zinc oxide with aluminum, zinc oxide with potassium, zinc oxide with silicon, or tin oxide, indium oxide-tin oxide, A conductive oxide such as zinc oxide-indium oxide-magnesium oxide may be used, or titanium oxide, tin oxide, tin oxide-hafnium oxide, silicon oxide-tin oxide, zinc oxide-tin oxide, or oxide may be used. An insulating metal oxide such as tin-titanium oxide may be used. The thickness is desirably set to 400 to 800 °.

The intermediate layer 7 has a low refractive index of 1.43 to 1.43.
It is a metal oxide having a refractive index of 1.7. For example, an insulating metal oxide such as silicon oxide, silicon oxide-tin oxide, or the like can be used, and has a thickness of 300 to 600 degrees.

The metal oxide 8 has a thickness of 100 to 500 mm and is made of ITO (indium-tin oxide), indium oxide, tin oxide with antimony, tin oxide with fluorine, zinc oxide with aluminum, zinc oxide with potassium, silicon oxide. Additive zinc oxide or tin oxide, zinc oxide-tin oxide, indium oxide-tin oxide, or zinc oxide-indium oxide-magnesium oxide-based metal oxide can be used. The metal oxide layer 8 is required to have a function as a resistive film in the case of a resistive film type, a capacitive type, or the like depending on a touch panel type.
The thickness is appropriately adopted. The thickness of each of the multilayer film structure, the metal oxide layer 8, the intermediate layer 7, and the undercoat layer 6 is set in consideration of optical balance.

As shown in FIG. 1, the multi-layer structure of at least three layers is laminated on at least one surface of the transparent substrate of the touch panel 1 so that the color of the LCD 2 and the color of the touch panel 1 can be adjusted. It becomes possible.

As shown in FIG. 2, λ / 4 retardation plates 106a, 107a,
When the polarizing plates 106b and 107b are stacked, the reflected light of the light transmitted through the touch panel is cut off by the combination of the two sets of the circularly polarizing plates 106 and 107, and the light emitted from the LCD is first λ. Λ / 4 retardation plate 10a becomes circularly polarized light by / 4 retardation plate 107a and is further laminated.
Since the light is converted into linearly polarized light by the light 6a, the light emitted from the LCD is not polarized, so that the brightness and the visibility of the display screen are less likely to be reduced.

There are various types of resistive touch panels, such as a digital touch panel, an analog touch panel, and a combination of both, but a transparent touch panel can be applied regardless of the detection principle.

Even when using a touch panel of the capacitance type, the ultrasonic type, or the optical type, if the touch panel is mounted on an LCD, the required quality, such as the fact that the touch panel is transparent and that there is little reflection, is a resistance film. The same as for the method,
The use of a circularly polarizing plate has the same effect and is often used, and in such a case, the present invention is similarly applicable.

As shown in FIG. 1, a λ / 4 retardation plate 4 and a polarizing plate 5 are laminated on the transparent substrate 3 of the transparent touch panel 1, and the surface of the polarizing plate (the surface of the outermost layer) is formed on the transparent substrate 3 as shown in FIG. By providing an anti-reflection film such as a hard coat layer (HC layer), the anti-reflection effect on the surface and the improvement of pen input durability (sliding resistance) are measured, and anti-glare processing is performed. May be.

(Effect) The touch panel 1 having the above-mentioned multilayer film structure is designed by designing a multilayer film structure of three or more layers having different refractive indices from the transparent substrate side so that the refractive index becomes high / low / high based on the refractive index. The peak wavelength of the color temperature of the transparent substrate
m or less, and the color matching between the touch panel and the LCD when a yellowish polarizing plate is combined can be easily performed. Further, by using the λ / 4 retardation plate 4 and the polarizing plate 5 together, the light emitted from the LCD is not polarized, so that the brightness of the screen can be maintained, and the image can be easily viewed and beautiful. Become.

In the case of a resistive touch panel, it is possible to use a transparent substrate 3 having a very thin thickness (several tens μm to several mm) such as a film or a glass plate. It is suitable for a wide range, especially for recent portable devices. Ultrasonic, capacitive, and optical touch panels have a simpler laminated structure with a smaller number of laminated films than the resistive film type,
It has good visibility and many advantages in terms of handling.Optical touch panels can be applied to large screens with high accuracy, and they have excellent transparency etc. Can be

(Embodiment 1) An embodiment of a resistive transparent touch panel 100 will be described in detail with reference to FIG. The touch panel 100 includes a fixed substrate 101 and a movable substrate 102 as shown in FIG. 2, and transparent conductive films 103 and 104 are formed on one surface of each substrate, respectively. And has a configuration in which they are opposed to each other with a small interval therebetween. The touch panel 100 has a circularly polarizing plate 107 (λ / 4 retardation plate 107a, polarizing plate 107
b) is laminated, and the polarizing plate 110 is attached to the other surface of the LCD 2 and used in combination.

Each substrate of the resistive touch panel may be a film, a sheet, or a thin plate. The combination of the fixed substrate 101 and the movable substrate 102 may be a film / glass, glass / Film, film / film, glass / glass and the like. For mounting on an LCD, a combination of film / glass / LCD is preferred. Each of the substrates is desirably formed of a transparent and optically isotropic material in order to enhance the image display quality of the LCD, and the fixed substrate 101 includes soda lime glass, tempered glass, polycarbonate or polymethyl. An acrylic resin plate such as methacrylate, a polyolefin resin substrate, or the like is often used. The movable substrate 102 is made of a polycarbonate resin sheet, an acrylic resin sheet, an amorphous polyolefin resin sheet, or a transparent polymer film such as polyether, polyarylate, uniaxially stretched polyethylene terephthalate, or polyether sulfone. Is used. In the present embodiment, JSR is an amorphous polyolefin resin and a norbornene resin having an aliphatic cyclic structure.
Arton Film (Arton is a registered trademark of the company)
You are using

On one surface of the movable substrate 102, indium tin oxide (hereinafter referred to as ITO:
A thin film having a thickness of 300 mm) is laminated. The refractive index of ITO is 2.0, and the transparent conductive film 103 corresponds to the metal oxide layer of the high refractive index layer included in the multilayer structure of the present invention. Then, in order to improve the adhesion between the substrate 102 and the transparent conductive film 103 and to improve the light transmittance, an insulating metal oxide layer of ZnSnO ₃ (600 °) is laminated on the substrate 102 as the undercoat layer 108. Si as an intermediate layer 109
O ₂ (300 °) is provided, and the transparent conductive film 10 is further formed thereon.
As No. 3, ITO is laminated. In order to further improve the adhesion between the film of the substrate and the metal oxide, the adhesion layer 108a
In some cases, a single Si layer (10 °) 108 a is laminated between the substrate 102 and the undercoat layer 108. On one surface of the movable substrate 102, that is, the transparent conductive film 103
Is composed of ARTON / Si / ZnSnO ₃ / Si
O ₂ / ITO.

The adhesion layer 108a is a metal layer composed of a single metal element or an alloy of two or more metal elements. The adhesion layer 108a is formed of a single element of silicon, titanium, tin, or zinc, or an alloy thereof. The thickness of the adhesion layer 108a is smaller than that of a silicon oxide (SiOx; X ≦ 2) layer conventionally used generally as an adhesion layer, and is 10 to 50 degrees.
It is desirable to set to Å. If it exceeds 50 °, the light transmittance is reduced, and the significance of interposing a multilayer film structure is lost. On the other hand, if it is less than 10 °, sufficient adhesion cannot be obtained.

On the other hand, on one surface of the fixed substrate 101,
A conductive thin film of the transparent conductive film 104 is laminated. The conductive thin film is made of tin oxide (SnO ₂ ), and is used for improving the adhesion between the fixed substrate 101 made of soda lime glass and the transparent conductive film 104 and for improving the light transmittance. An intermediate layer 110 is provided between the
As the SiO ₂ is provided, between the intermediate layer 110 and the substrate 101, laminating the metal oxide layer of SnO ₂ as an undercoat layer 111. Layer structure including a transparent conductive film of the fixed substrate 101, a glass / SnO ₂ / SiO ₂ / SnO _2, and the refractive index of the SnO ₂ is 1.8, SiO ₂ is 1.46, light due to the difference in refractive index It is designed to improve the transmittance. Actually, AR glass: A0 which is a product of Asahi Glass Co., Ltd. having the above-described layer configuration as the fixed substrate 101
70S03 (0.7 mm) is adopted.

In the resistive touch panel 100,
The structure has a multilayer structure of three layers each including a transparent conductive film provided on each of the movable substrate 102 and the fixed substrate 101. In this case, the light transmittance of each substrate is further improved by forming a multilayer film structure by alternately combining materials having large and small light refractive indexes, and the substrate and the transparent conductive film are formed by stacking a single Si layer. It is also known that there is an effect of further improving the adhesion.

These metal oxide layers and metal layers can be formed by sputtering, vapor deposition, coating method or the like. However, when formed by coating, it is necessary to appropriately mix a binder or the like, which is disadvantageous for transparency. The following is preferred.

Further, the adhesion layer 1 laminated on the movable substrate 102
Before forming 08a, the surface of the substrate 102 is subjected to fine unevenness processing, and then an adhesion layer is formed. The fine concavo-convex layer may be formed by embossing the film or by applying fine particles together with a binder and then drying. As the size of the fine unevenness, the average roughness (Rz) is 0.5 to 5
It is about 0 μm, and the adhesion layer, undercoat layer, intermediate layer, and transparent conductive film are formed on it, and it is placed opposite to the fixed substrate via the spacer. It is possible to prevent the occurrence of Newton rings between the membranes.

A circularly polarizing plate 10 is provided on the other surface of each substrate.
6 and 107 are laminated, and the same circular polarizing plates 106 and 107 are stacked.
May simply be a polarizing plate, but preferably are λ / 4 retardation plates 106a and 107a, and polarizing plates 106b and 10b.
7b is desirable, and each is laminated on the substrate in the order of retardation plate / polarizing plate. Polarizing plates 106b, 107b
In practice, a film formed by stretching a polyvinyl alcohol (PVA) film to have birefringence and sticking it from above and below with a triacetyl acetate (TAC) film is used. . In this example, the PVA film had a thickness of 20 mm.
μm, and the thickness of two TAC films is 160 μm.
m.

The λ / 4 retardation plates 106a and 107a
Is formed using a polycarbonate (PC) film as a material, and is used by being bonded to the polarizing plates 106a and 107a. The circularly polarizing plate 107 may be laminated on the surface of the LCD 2 in advance, or may be laminated on the fixed substrate 101 of the touch panel 100 and then mounted on the LCD 2. Then, a polarizing plate 112 may be laminated on another surface of the LCD. Further, a generally used hard coat layer (not shown) is laminated on the surface of the polarizing plate 106b, or a protective film, a PET film or the like is laminated as a reinforcing film to reduce the reflection on the surface,
Improves pen input durability and further improves touch panel 100
It is also possible to prevent deformation due to the difference in thermal characteristics between the layers due to the temperature change. At this time, as shown in Table 1, the peak wavelength of the color temperature of the light of the movable substrate 102 was 470 nm, the peak wavelength of the light of the fixed substrate was 500 nm, and the peak wavelength of the touch panel 100 was 480 nm.

(Embodiment 2) As shown in FIG. 3, the embodiment 2 is a combination of the resistive touch panel 200 and the LCD 2 of the same system as the embodiment 1, and the touch panel 200 includes a fixed substrate 201, a movable substrate 202, Polarizing plate 206 (206
a, 206b) and 207 (207a, 207b) are combined with each other,
An undercoat layer 209 is formed by laminating a metal oxide layer of O ₃ .
The SiO ₂ is provided as will be stacked SnO ₃ as a transparent conductive film 204 thereon, the movable substrate 202, the adhesion layer of the present invention, a standard ITO film transparent conductive film 203 without laminating the undercoat layer Are directly laminated on a substrate. As a standard ITO film, I
A TO film is formed, and an undercoat layer (S
iO ₂ etc.). On the other surface of the movable substrate 202, a λ / 4 retardation plate 206a,
After the polarizing plates 206b are sequentially laminated, the protective film 21
A PET film is laminated as 0, and an anti-reflection film 211 is laminated on the other surface of the PET film. The protective film 210 has a smaller heat shrinkage than the movable substrate 202 and the polarizing plate 206, and functions to suppress thermal deformation due to the surrounding thermal environment. In this case, one set of the multilayer film configuration of the present invention is laminated on the fixed substrate, and other conditions are the same as those in the first embodiment. At this time, Table 1
As shown in the figure, the peak wavelength of the color temperature of light on the movable substrate 202 is 800 nm, and the peak wavelength of light on the fixed substrate is 50 nm.
0 nm, and the peak wavelength of the touch panel 200 was 550 nm.

(Comparative Example 1) As shown in FIG. 4, the touch panel 300 as a comparative example is a case where the adjustment of the color tone is ignored and only the improvement of the adhesion is a problem when the multilayer structure is laminated. On the fixed substrate 301, a transparent conductive film 304 of SiO ₂ is laminated as an undercoat layer 308, and a transparent conductive film 304 of ITO is laminated thereon.
This is a configuration in which only an O layer is provided. Of course, the configuration in which the polarizing plates are combined is the same as in the first and second embodiments.
6 (combination of a λ / 4 retardation plate 306a and a polarizing plate 306b) on the other surface of the movable substrate 302, and
Mounted on D2. A circular polarizer 307 (a combination of a λ / 4 retardation plate 307a and a polarizer 307b) was laminated between the touch panel 300 and the LCD 2, and a polarizer 310 was attached to the other surface of the LCD 2. The surface image has a slight color tone even when observed visually and is hard to see. As shown in Table 1, the peak wavelength of the color temperature of the light of the movable substrate 302 is 800 nm, and the peak wavelength of the light of the fixed substrate 301 is The wavelength was also 800 nm, and the peak wavelength of the touch panel 200 was also 800 nm.

Table 1 shows the data of the peak wavelength and Table 2 shows the color temperature, luminance, and luminance transmittance as the optical characteristics relating to Example 1, Example 2, and Comparative Example 1. LC combined
D is a TFTLCD manufactured by Sharp Corp., product number: L
It was evaluated in combination with Q10D345. The measuring device is a color luminance meter (BM-7): manufactured by Topcon (Tokyo Optical Machinery Co., Ltd., spectrophotometer: U-3410 manufactured by Hitachi, Ltd.).

[0038]

[Table 1]

[0039]

[Table 2]

Referring to Tables 1 and 2, the touch panel of Example 1 has a peak wavelength set to 480 nm, so
It can be understood that since the color temperature when combined with D does not differ greatly from the color temperature of the LCD alone, there is almost no change in color. In the second embodiment, since the peak wavelength is set to 550 nm, the color temperature is considerably shifted (6125 → 5446) in the current LCD. Occurrence of tint is small compared to the comparative example, and it can be adopted depending on the use. As described above, by laminating the multilayer film configuration of the present invention on the substrate of the touch panel, the peak wavelength of the touch panel can be adjusted, and the effect when combined with the LCD, without reducing the brightness of the screen. ,
The hues are not visually observed, there is no difficulty in seeing due to the reflected light, and the appearance is very good in terms of sensation.

(Alternative Embodiment 1) Further, even in the touch panel 400 having the layer configuration shown in FIG. 5, the color tone can be similarly adjusted. In the touch panel 400, a fixed substrate 401 is a glass substrate, an ITO film is formed as a transparent conductive film 404 on the glass substrate, a PET film is formed as the movable substrate 402, and an ITO film is formed as the transparent conductive film 403 thereon. On the other side, a circular polarizing plate 406 is attached, and on the other side of the fixed substrate 401, a PET film 410 on which 409, 408, and 407 are laminated as a multilayer film structure of the present invention is attached to the front surface. It was suitable for use in combination with an LCD.

(Another Embodiment 2) An ultrasonic touch panel 50 is shown in FIG. Transparent substrate 51 that transmits surface acoustic waves
A transparent resin plate is used, and the surface can be subjected to a scratch resistance treatment such as a non-glare treatment and a hard coating. The surface acoustic wave is transmitted from an ultrasonic oscillator 52 provided at one corner, is reflected by a plurality of reflection gratings 53 at the X direction or Y direction end of the substrate 51, and is reflected on the upper surface of the substrate 51. It is transmitted in the XY directions. The light is reflected by the reflection gratings 54 provided opposite to each other and received by the wave receiving element 55 provided at the corner of the end. The wave receiving element 55 detects an output signal corresponding to the traveling time of the acoustic wave, and the output signal is processed by a signal processing circuit and converted into a pressed position. At this time, if necessary, that is, in order to prevent reflection from the interface of the LCD substrate, the conductive layer, etc., the substrate 5 of the touch panel 50 may be used.
A λ / 4 retardation plate 59 and a polarizing plate 60 are stacked on the lower surface of the first substrate 1. At this time, an undercoat layer 56 made of a metal oxide layer is formed on the upper or lower surface (the lower side in the drawing) of the substrate 51 in order from the substrate side as the multilayer structure of the present invention.
(SnO ₂ ) is formed, then an intermediate layer 57 (SiO ₂ ) is stacked, and SnO ₂ is further stacked as a metal oxide layer 58.

At this time, by adjusting the thickness of the undercoat layer 56 to a peak wavelength of 500 nm or less, the yellowish color of the polarizing plate could be eliminated. By combining the ultrasonic touch panel 50 on the LCD 2, the display on the LCD has no change in color.
It has become possible to maintain that quality. Of course, the screen was clean and easy to see without reflection or reflection.

Furthermore, the peak wavelength of the touch panel can be adjusted by appropriately laminating the multilayer film structure of the present invention even if it is a capacitance type or optical touch panel.

According to the first and second aspects of the present invention, when a transparent touch panel is mounted on an LCD and used as described in the embodiments, the transparent touch panel is often used by being laminated with a polarizing plate. By laminating at least three or more layers of a multilayer structure together with the polarizing plate on the substrate, the color of the polarizing plate can be canceled out, and a clear screen can be obtained without changing the color of the LCD.

According to a third aspect of the present invention, when a transparent touch panel is combined with an LCD, by using a combination of a λ / 4 retardation plate and a polarizing plate as a polarizing plate together with a multilayer film structure, a screen with no hue is provided. This has the effect that a bright image surface can be obtained.

Claims 4, 5, 6, and 7
The invention described in (1) has an effect that by applying the present invention to each type of touch panel, the touch panel can be effectively used in combination with an LCD in a specific application range of each touch panel.

[0048]

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a touch panel for a liquid crystal display of the present invention.

FIG. 2 is a sectional view of a main part of a first embodiment of a resistive touch panel according to the present invention.

FIG. 3 is a sectional view of a main part of a resistive touch panel according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view of a comparative example of a resistive touch panel according to the present invention.

FIG. 5 is a cross-sectional view of a main part of a resistive touch panel according to another embodiment 1 of the present invention.

FIG. 6 is a sectional view of a main part of an ultrasonic touch panel according to another embodiment 2 of the present invention.

[Explanation of symbols]

 1 Transparent touch panel 2 LCD 3 Transparent substrate 4 λ / 4 retarder 5 Polarizer 6 Undercoat layer 7 Intermediate layer 8 Metal oxide layer 9 Polarizer 10 λ / 4 retarder 50 Ultrasonic touch panel 100 Resistive touch panel 200 Resistive touch panel 300 Resistive touch panel 400 Resistive touch panel

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H089 HA18 QA11 QA16 2H091 FA08X FA08Z LA03 LA11 LA17 5B087 CC02 CC12 CC14 CC34 5G435 AA02 BB12 CC12 EE32 FF05 GG01 HH02 HH12

Claims (8)

[Claims] 1. A transparent touch panel mounted on a liquid crystal display for use in combination with a polarizing plate, adjusting the peak wavelength of light transmittance of the touch panel, and adjusting the color of the liquid crystal display even when the touch panel is mounted. A liquid crystal display touch panel characterized by matching the color of the liquid crystal display and the transparent touch panel with no change in color. 2. The transparent substrate of the transparent touch panel has a multilayer structure of at least one set of three or more layers, and a peak wavelength of light transmittance of the touch panel is selectively set. LCD display touch panel. 3. The polarizing plate comprises a polarizing plate alone or a combination of a polarizing plate and a λ / 4 retardation plate, and a polarizing plate or λ / 4 is provided on an upper surface and / or a lower surface of a transparent substrate of a transparent touch panel. 3. The touch panel for a liquid crystal display according to claim 1, wherein a retardation plate and a polarizing plate are laminated. 4. The touch panel for a liquid crystal display according to claim 1, wherein the touch panel is a resistive touch panel and has at least one set of three or more multilayer conductive films including a resistive film. 5. The touch panel according to claim 1, wherein the touch panel is an ultrasonic touch panel, and has at least one set of three or more multi-layer films on a front surface or a back surface of a transparent substrate.
The touch panel for liquid crystal display according to 1. 6. The touch panel is an optical touch panel, and has at least one set of 3 on the front or back surface of a transparent substrate.
The touch panel for a liquid crystal display according to claim 1, wherein the touch panel has a multi-layer structure of at least two layers. 7. The touch panel is a capacitive touch panel, and has one resistive film on a surface of a transparent substrate and a multilayer conductive film structure of three or more layers including the resistive film, or at least a resistive film on a rear surface side of the transparent substrate. The touch panel for a liquid crystal display according to claim 1, wherein the touch panel has a set of three or more multilayer films. 8. The multi-layer structure of three or more layers includes a high refractive index layer of at least 1.7 to 2.3 from the surface of the substrate, 1.4.
The liquid crystal display touch panel according to any one of claims 1 to 7, wherein the touch panel has a multilayer structure of three or more layers including a low refractive index layer and a high refractive index layer of 3 to 1.7.