JP2006251859A - Touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch panel that is strong and light, can completely prevent glass fragments from scattering about the touch panel even when an input load or drop impact breaks a transparent glass plate, and excels in visibility despite using inexpensive surface-untreated glass. <P>SOLUTION: In the touch panel 1, in which a lower electrode member having a transparent electrode 3 formed on an upper surface of a transparent resin film 2 having a thickness of 25 to 200 μm and an upper electrode member having a transparent electrode 3 formed on a lower surface of a transparent resin film 2 are opposed via a spacer 4, and the transparent glass plate 6 having a thickness of 0.4 to 3.0 mm is stuck all over a lower surface of the lower electrode member, a transparent reinforcement film 8 having a thickness of 25 to 200 μm is stuck all over a lower surface of the transparent glass plate 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is mounted on a portable electronic device equipped with a liquid crystal display such as a cordless telephone, a mobile phone, a calculator, a sub-notebook personal computer, a PDA (personal digital assistant), a digital camera, a video camera, a monitor of a personal computer, etc. The present invention relates to a touch panel in which position input is performed by pressing from above with a finger, a pen, or the like in accordance with an instruction on a fluoroscopic screen.

  As a general configuration of the touch panel, a lower electrode material in which the transparent electrode 3 is formed on the upper surface of the transparent resin film 2 and an upper electrode material in which the transparent electrode 3 is formed on the lower surface of the transparent resin film 2 are interposed via a spacer. There is one which is disposed so as to be opposed to each other, and a transparent resin plate 9 is bonded to the entire lower surface of the lower electrode material as a support plate (see FIG. 2). In addition, there is a configuration in which the support electrode is not used and the transparent electrode 3 is directly formed on the upper surface of the transparent resin plate 9 (see FIG. 3) or the transparent glass plate 12 (see FIG. 4).

  However, when the transparent glass plate 12 with the transparent electrode 3 is used as the lower electrode material (see FIG. 4), the surface strength is increased when an abnormally large load is applied to the surface of the transparent glass plate 12 due to input. Insufficient transparency glass plate 6 might break. In addition, when the device on which the touch panel 1 is mounted is accidentally dropped or bumped and an impact is applied to the end face or the corner of the transparent glass plate 6, the edge strength is insufficient and the transparent glass plate 6 is broken. was there. And as a result of the transparent glass plate 6 being broken, the liquid product panel that displays the lower image of the touch panel 1 and the front light that illuminates for this image display are severely damaged, making it impossible to visually recognize characters and images. Glass fragments were scattered in the product, and it took a lot of time to replace and clean the touch panel or its components.

  Further, in the case of the configuration using the transparent resin plate 9 with the transparent electrode 3 as the lower electrode material, or using the transparent resin film 2 with the transparent electrode 3 as the lower electrode material, this is applied to the transparent resin plate 9 over the entire surface. When the transparent resin plate 9 is subjected to a load due to input, the transparent resin plate 9 may be greatly bent and come into contact with the surface of the liquid crystal panel or the front light. The liquid crystal panel causes bleeding when the transparent resin plate 9 comes into contact with the display surface, and the front light comes into contact with the transparent resin plate 9 and the surface is damaged, and abnormal light emission occurs during lighting. -The image cannot be viewed correctly.

Therefore, the present applicant has proposed a configuration as previously described in Patent Document 1 as means for solving these problems. That is, in the touch panel in which the lower electrode material in which the transparent electrode is formed on the upper surface of the transparent resin film and the upper electrode material in which the transparent electrode is formed on the lower surface of the transparent resin film are arranged to face each other via the spacer, the lower electrode material A configuration in which a transparent glass plate having a thickness of 0.4 to 3.0 mm is bonded to the entire lower surface (see FIG. 5), or a configuration in which the arrangement of the transparent glass plate and the transparent resin film 2 of the lower electrode material is replaced ( 6), even if a significantly large input load is applied to the touch panel and the transparent glass plate is cracked, the transparent electrode side or the opposite side is bonded to the entire surface with the transparent resin film. The glass can be prevented from scattering.
JP 2002-278701 A

  However, the touch panel of the configuration described in Patent Document 1, has the disadvantage of inevitably heavy because of the use of a transparent glass plate, has become unsuitable for applications where weight reduction such as a cellular phone advances. Of course, if the transparent glass plate is made thin, weight reduction can be easily achieved, but this causes a new problem that the strength is lowered.

  Moreover, although the touch panel of the structure described in the said patent document 1 can prevent scattering of broken glass, since only the single side | surface of a transparent glass plate is covered with the transparent resin film, it is glass fragments slightly. May be scattered around the touch panel.

Further, when a transparent glass plate is bonded to the entire lower surface of the lower electrode material as shown in FIG. 5, since glass is usually used from the cost aspect, the glass is exposed on the back surface of the touch panel. The untreated glass surface is affected by humidity over time, and fogging occurs due to alkali component precipitation. For example, when wiping with a solvent or alcohol at the time of touch panel product inspection, it will appear as uneven wiping in the future, resulting in a product with poor visibility. As a countermeasure against uneven wiping, it may be possible to attach a passivation film such as SiO _{2 to} the exposed surface, but this increases the cost.

  Therefore, the object of the present invention is to solve the above-mentioned problems, high strength and light weight, and even if the transparent glass plate is broken by the input load or the impact of dropping, the scattering of the glass fragments around the touch panel is completely achieved. It is another object of the present invention to provide a touch panel that can be prevented and that has excellent visibility even when inexpensive surface-untreated glass is used.

  In order to achieve the above object, the present invention comprises a lower electrode material in which a transparent electrode is formed on the upper surface of a transparent resin film having a thickness of 25 to 200 μm, and an upper electrode material in which a transparent electrode is formed on the lower surface of the transparent resin film. In a touch panel in which a transparent glass plate having a thickness of 0.4 to 3.0 mm is bonded to the entire lower surface of the lower electrode material, the transparent reinforcement having a thickness of 25 to 200 μm is applied to the entire lower surface of the transparent glass plate. It comprised so that a film might be bonded together.

  Since the touch panel of the present invention has the above-described configuration, the following effects are achieved.

  That is, with a transparent glass plate having a thickness of 0.4 to 3.0 mm sandwiched between a transparent resin film having a thickness of 25 to 200 μm and a transparent reinforcing film having a thickness of 25 to 200 μm, the lower electrode material is adhered on the entire surface. High strength is obtained because they are combined. Therefore, the weight of the touch panel can be reduced by reducing the thickness of the transparent glass plate while maintaining the strength of the touch panel.

  In addition, since both sides of the transparent glass plate are covered with the above films, even if a significantly large input load is applied to the touch panel and the transparent glass plate breaks, the glass fragments remain in the film covering both sides of the touch panel. Can be completely prevented.

  Moreover, since both surfaces of the transparent glass plate are covered with the above-mentioned films, even if inexpensive surface-untreated glass is used, fogging due to humidity does not occur and the visibility is excellent.

  Hereinafter, a touch panel according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a touch panel according to the present invention. In the figure, 1 is a touch panel, 2 is a transparent resin film, 3 is a transparent electrode, 4 is a spacer, 5 is a dot spacer, 6 is a transparent glass plate, 7 is an adhesive, and 8 is a transparent reinforcing film.

  The touch panel 1 shown in FIG. 1 includes a lower electrode material in which a transparent electrode 3 is formed on the upper surface of a transparent resin film 2 having a thickness of 25 to 200 μm, and an upper electrode material in which the transparent electrode 3 is formed on the lower surface of the transparent resin film 2. The transparent glass plate 6 having a thickness of 0.4 to 3.0 mm is bonded to the entire lower surface of the lower electrode material, and the transparent reinforcement having a thickness of 25 to 200 μm is applied to the entire lower surface of the transparent glass plate 6. The film 8 is bonded.

  As the transparent resin film 2 of the upper electrode material, it is necessary to have flexibility for input, and engineering plastics such as polycarbonate, polyamide, polyether ketone, etc. having a thickness of 75 to 250 μm are generally used, acrylic, polyethylene Resin films such as terephthalate and polybutylene terephthalates, and laminates thereof are used. A hard coat layer may be formed on the upper surface of the upper electrode material. The hard coat layer may be an inorganic material such as a siloxane resin, or an organic material such as an acrylic epoxy or urethane thermosetting resin or an acrylate photocurable resin. The thickness of the hard coat layer is suitably about 1 to 7 μm. Further, the upper electrode material may be subjected to non-glare treatment on the upper surface to prevent light reflection. For example, the transparent resin film or the hard coat layer is processed to be uneven, or the hard coat layer is mixed with fine particles such as extender pigments, silica, and alumina.

  Examples of the transparent resin film 2 for the lower electrode material include engineering plastics such as polycarbonate, polyamide, and polyether ketone, resin films such as acrylic, polyethylene terephthalate, and polybutylene terephthalate, and laminates thereof. Used. If the thickness of the film is less than 25 μm, when the transparent glass plate 6 is cracked, glass fragments may break through the film. On the other hand, when the thickness of the film exceeds 200 μm, the flexibility of the film is lacking and the assembly efficiency is deteriorated.

  As the transparent electrode 3 formed on each transparent resin film 2, a metal film or metal oxide film having transparency and conductivity is formed by a method such as vacuum deposition, sputtering, or ion plating. For example, metal oxide films such as ITO, tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide, composite films mainly composed of these metal oxides, gold, silver, copper, tin, nickel, aluminum, palladium There is a metal film. The thickness of the transparent electrode is generally 0.01 to 0.1 μm.

  The spacer 4 is formed in the form which can insulate between the transparent electrodes 3 of a lower electrode material and an upper electrode material, for example, a frame shape. As the material of the spacer 4, in addition to the resin film similar to the base material of the lower electrode material and the upper electrode material, an appropriate resin such as an acrylic resin, an epoxy resin, or a silicone resin is printed or applied. Although the spacer 4 can be formed, generally, the spacer 4 is often used also as an adhesive layer made of a double-sided tape in the form of a frame for fixing the lower electrode material and the upper electrode material, an adhesive or an adhesive. When forming an adhesive layer made of an adhesive or a pressure-sensitive adhesive, screen printing or the like is used. The thickness of the spacer 4 is generally 10 μm to 200 μm.

  In the case of the touch panel 1 shown in FIG. 1, in addition to the frame-shaped spacer 4, dot-like spacers 5 are further formed on the surface of the transparent electrode 3 as the lower electrode material. The dot spacer 5 secures a gap between the lower electrode material and the transparent electrode 3 of the upper electrode material, controls the input load, or the lower electrode material after input when forming a large touch panel. And the upper electrode material are formed to improve separation. As the dot spacer 5, for example, a transparent photocurable resin such as melamine acrylate resin, urethane acrylate resin, epoxy acrylate resin, methacryl acrylate resin, acrylate resin such as acrylic acrylate resin, or polyvinyl alcohol resin is finely processed by a photo process. It can be obtained in the form of dots. Also, a large number of fine dots can be formed by a printing method using a urethane-based transparent resin or the like to form a spacer. It can also be obtained by spraying or applying a dispersion of particles made of inorganic or organic matter and drying. The dot spacers 5 are generally formed in a dot shape having a diameter of 30 to 100 μm and a height of 1 to 15 μm, and are arranged at regular intervals of 0.1 mm to 10 mm.

  Since the transparent glass plate 6 does not bend even when an input load is applied, the surface of the liquid crystal panel or the front light can be prevented from being damaged. As the transparent glass plate, a soda glass or a borosilicate glass having a thickness of 0.4 to 3.0 mm can be used. If the thickness of the transparent glass plate is less than 0.4 mm, the rigidity is insufficient, and if it exceeds 3.0 mm, parallax occurs and the screen becomes difficult to see.

  As the transparent reinforcing film 8, engineering plastics such as polycarbonate, polyamide and polyether ketone, resin films such as acrylic, polyethylene terephthalate and polybutylene terephthalate, and laminates thereof are used. If the thickness of the film is less than 25 μm, when the transparent glass plate 6 is cracked, glass fragments may break through the film. On the other hand, when the thickness of the film exceeds 200 μm, the flexibility of the film is lacking and the assembly efficiency is deteriorated.

  The lower electrode material and the transparent glass plate 6, and the transparent glass plate 6 and the transparent reinforcing film 8 are all bonded together by the adhesive material 7 or the like. Therefore, even if a significantly large input load is applied to the touch panel 1 and the transparent glass plate 6 is broken, glass fragments can be held between the films, and scattering around the touch panel 1 can be completely prevented. Moreover, even if the touch panel 1 is accidentally dropped or bumped and the transparent glass plate is broken, the same applies. Therefore, it is difficult to replace and clean the touch panel 1 and its components. Further, the surface of the liquid crystal panel or the front light can be prevented from being damaged by the scattered glass, and characters and images can be visually recognized correctly. As the adhesive 4, an acrylic adhesive, a silicon adhesive, a double-sided adhesive tape, or the like can be used. In particular, the transparent glass plate 6, the transparent resin film 2 of the lower electrode material, the transparent reinforcing film 8 and the refractive index. It is more preferable to use an approximation of

  Further, the lower surface of the transparent reinforcing film 8 may be subjected to a low reflection treatment. The low reflection treatment includes a treatment such as applying a low reflection material using a low refractive index resin such as fluorine resin or silicon resin, or forming a metal multilayer film.

  A 0.1 mm thick PET substrate ITO film (ITO film thickness 20 nm) was used as the lower electrode material, and a 0.5 mm thick plate glass was bonded to the entire surface with a 0.05 mm thick substrate-less acrylic adhesive on the back surface. . Moreover, the transparent reinforcement film which consists of a PET base material low hard coat film (acrylic-type hard-coat film thickness of 5 micrometers) of 0.06 mm thickness on the back surface of the plate glass was bonded together with the said base-less adhesive.

  On the other hand, a PET base ITO film (ITO film thickness 20 nm) having a thickness of 0.2 mm is used as the upper electrode material, and this is made to face the laminate including the lower electrode material and the electrode surface, and a double-sided adhesive tape having a thickness of 60 μm is framed. The peripheral portion (width 2 mm) was bonded using a punched shape, and a touch panel having a F (film) / F / G (glass) / F configuration of 45 mm length and 60 mm width was obtained.

<Comparative Example 1>
A touch panel was obtained in the same manner as in the example, except that the film was not bonded to the back side of the plate glass to obtain an F / F / G configuration and the plate glass was thickened so that the total thickness of the touch panel was the same as in the example.

<Comparative example 2>
Same as the example except that the ITO film is directly formed on the surface of the plate glass without forming a film to form an F / G / F configuration, and the plate glass is thickened so that the total thickness of the touch panel is the same as the example. A touch panel was obtained.

<Comparative Example 3>
A touch panel was obtained in the same manner as in the example except that a polycarbonate resin plate was used instead of the plate glass and the F / F / P (plastic) / F configuration was adopted.

<Evaluation 1>
Two strength tests were performed on the touch panels of Example (F / F / G / F), Comparative Example 1 (F / F / G), and Comparative Example 2 (F / G / F). First, a flat steel plate with a width of 2 mm was used to support the four sides of the touch panel, and a steel ball static pressure test was performed by pressing a steel ball with a diameter of 16 mm in a direction perpendicular to the touch panel at a constant speed of 10 mm per minute. Whereas Examples 1 and 2 were cracked at a load of 40 kgf, the Examples were not cracked up to a load of 50 kgf even though the thickness of the plate glass was thinner than that of Comparative Example 1 (the total thickness was the same). Further, when an impact test was performed in which a steel ball having a diameter of 30 mm and a weight of 130 g was dropped from a height of 0.4 m by using a smooth iron plate having a width of 2 mm and supporting four sides of the touch panel, Comparative Examples 1 and 2 were repeated 10 times. In contrast to cracking 4 times in the middle, in the example, although the thickness of the plate glass was thinner than that of Comparative Example 1 (the total thickness was the same), it was only cracked twice in 10 times.

<Evaluation 2>
At the same time, with respect to the touch panels of Example (F / F / G / F) and Comparative Example 2 (F / G / F), when the glass plate is broken by the above two strength tests, the glass is scattered downward. It was confirmed. As a result, in Comparative Example 2, it was confirmed that the glass fragments were slightly scattered around the touch panel, whereas in the example, the glass fragments stayed in the film covering both surfaces and there was no scattering around the touch panel. It was.

<Evaluation 3>
Moreover, when the touch panel of Example (F / F / G / F) and Comparative Example 1 (F / F / G) was subjected to a reliability test in a humid heat environment (test conditions: 60 ° C., 90%, 240 h). In Comparative Example 1, a whitening phenomenon occurred on the back surface of the glass, but the examples remained transparent and excellent in visibility.

<Evaluation 4>
Moreover, the above-mentioned steel ball static pressure test was also conducted on the touch panel of Comparative Example 3 (F / F / P? / F), and the amount of deflection was compared with that of the example. As a result, the load was 100 gf, 250 gf, 500 gf, and 1000 gf. The amount of bending is 0.7 mm, 1.3 mm, 2.0 mm, and 2.6 mm in Comparative Example 3, respectively, whereas in the example, the amount of bending is 0.3 mm, 0.8 mm, 1.1 mm, and 1.3 mm. There were few. When the amount of bending is small, it is difficult for the screen to blur due to the touch panel touching the liquid crystal panel, and the visibility is excellent. Of course, even if the amount of bending is large, bleeding can be prevented if sufficient clearance is provided between the touch panel and the liquid crystal panel, but the product becomes thicker by the clearance.

It is sectional drawing which shows one Example of the touchscreen which concerns on this invention. It is sectional drawing which shows an example of the touchscreen which concerns on a prior art. It is sectional drawing which shows an example of the touchscreen which concerns on a prior art. It is sectional drawing which shows an example of the touchscreen which concerns on a prior art. It is sectional drawing which shows an example of the touchscreen which concerns on a prior art. It is sectional drawing which shows an example of the touchscreen which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Touch panel 2 Transparent resin film 3 Transparent electrode 4 Spacer 5 Dot spacer 6 Transparent glass plate 7 Adhesive material 8 Transparent reinforcement film 9 Transparent resin plate

Claims (1)

A lower electrode material in which a transparent electrode is formed on the upper surface of a transparent resin film having a thickness of 25 to 200 μm and an upper electrode material in which a transparent electrode is formed on the lower surface of the transparent resin film are opposed to each other with a spacer interposed therebetween. In a touch panel in which a transparent glass plate having a thickness of 0.4 to 3.0 mm is bonded to the entire lower surface of
A touch panel, wherein a transparent reinforcing film having a thickness of 25 to 200 μm is bonded to the entire lower surface of the transparent glass plate.

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