JP2012226395A - Touch panel and display device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch panel which prevents the occurrence of interference fringes without increasing the cost.SOLUTION: An upper transparent substrate 2 having an upper transparent electrode formed thereon and a lower transparent substrate 3 having a lower transparent electrode formed thereon are bonded together with a sealant 7 provided on the outer periphery of a touch panel 1. A structure thicker than the sealant 7 is provided more inside the panel than the sealant 7, so that the upper transparent substrate 2 has an inclination to rise from an end part to the inside. In this manner, the inclination corresponding to the height of the structure is formed from the sealant 7 on the outer periphery of the panel toward the center of the panel. The structure can be constituted of dot spacers 5 formed in the panel or may be constituted by laminating a step 6 produced with the same material as the dot spacers 5 simultaneously with production of the dot spacers 5 and the same material as the sealant 7.

Description

  The present invention relates to a touch panel that performs press input with a finger, an input pen, or the like, and a display device including the touch panel.

  The touch panel is disposed on the upper surface of a display device such as a liquid crystal panel, and is used to select and input information displayed using a finger, an input pen, or the like, or to input characters or figures. As its operation principle, there are an analog resistance film system that detects coordinates inputted from resistance partial pressure generated by pressing, a digital resistance film system that detects conduction positions generated by pressing upper and lower electrodes arranged in a matrix, and the like. In these resistive film type touch panels, an upper substrate having a transparent electrode formed in a desired pattern on the lower surface of a flexible transparent substrate, and a transparent electrode and dots formed in a desired pattern on the upper surface of the transparent substrate. A lower substrate having a spacer is disposed opposite to each other with a predetermined gap, and the periphery is bonded and fixed by a sealing material. This touch panel is used by being arranged on the upper surface of a display device such as a liquid crystal panel.

  As described above, the resistive film type touch panel has a configuration in which the upper substrate and the lower substrate are bonded and fixed to each other by the sealing material provided in the periphery. From the viewpoint of operability, it is necessary to bring the upper and lower substrates into contact with each other even with a light press, and therefore the gap between the upper and lower substrates must be several tens to several hundreds of micrometers even at the largest portion. Therefore, there is a problem that interference fringes are generated when the upper substrate and the lower substrate come close to each other within the touch panel surface. In particular, the corner portion of the touch panel has a problem in that interference fringes are more noticeably generated because the degree of freedom is low because the adhesive is fixed by sealing materials in both the vertical and horizontal directions, and the gap is not increased.

  In order to solve such a problem, in the touch panel in which the sealing material is bonded around the outer peripheral area of the upper and lower substrates, the upper substrate is placed outside by arranging the routing wiring slightly thicker than the sealing material. There has been proposed a configuration that curves toward the front (see, for example, Patent Document 1).

  In addition, a method of making the upper substrate convex by providing an inclination or a step in the sealing material formation region of the lower substrate has been proposed (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 2004-280759 JP 2011-14024 A

  However, the configuration of Patent Document 1 requires a step of providing wiring by Ag paste or the like separately from the sealing material that circulates around the outer peripheral region. In addition, since it is necessary to form dot spacers separately, there is a problem in that the man-hour, that is, the cost is increased.

  Further, the technique described in Patent Document 2 requires a processing step in which an inclination or a step is provided on the lower substrate in advance. In addition, there is a problem that the strength is lowered by thinly processing the lower substrate. Therefore, the present invention relates to a touch panel that can improve interference fringes at low cost without adding a new process.

  In order to solve the above problems, the present invention is configured as follows. That is, a pair of transparent substrates disposed with a gap therebetween, a transparent electrode formed on the transparent substrate, a dot spacer formed on one of the transparent substrates, and a pair of transparent substrates formed around the transparent substrate. In the touch pal equipped with a sealing material that adheres and fixes the transparent substrate, a step with the same film thickness as the dot spacer is provided on the inner side of the panel than the sealing material by the dot spacer material, and the slope is inclined inward from the edge. I decided to have it. Here, a sealing material may be provided on the step. In addition, it can be formed at a time by making the sealing material formed around the transparent substrate and the sealing material formed on the step common. In addition, the formation of the dot spacer and the step can be performed simultaneously to simplify the manufacturing process. A dot spacer and a level | step difference can be formed by the photolithographic method etc. which used the photosensitive resist. The photosensitive resist may be applied directly on the transparent substrate on which the transparent electrode is formed, or may be provided by laminating a film-like one on the transparent substrate on which the transparent electrode is formed.

  According to the present invention, since an inclination corresponding to the height of the structure can be formed from the sealing material formed around the transparent substrate toward the center of the panel, no interference fringes are generated. In addition, since the structure can be formed without adding a process, there is no increase in cost.

1 is a cross-sectional view illustrating a schematic configuration of a touch panel according to Example 1. FIG. 1 is a schematic cross-sectional view of a liquid crystal display device including a touch panel according to Example 1. FIG. 6 is a cross-sectional view illustrating a schematic configuration of a touch panel according to Embodiment 2. FIG. 6 is a schematic cross-sectional view of a liquid crystal display device including a touch panel according to Example 2. FIG.

  The touch panel of the present invention has a configuration in which an upper transparent substrate on which an upper transparent electrode is formed and a lower transparent substrate on which a lower transparent electrode is formed face each other with a gap. The upper transparent substrate and the lower transparent substrate are bonded by a sealing material provided on the outer periphery of the panel. Dot spacers are formed on the inner surface of one of the upper transparent substrate and the lower transparent substrate. At this time, a structure thicker than the sealing material is provided inside the panel than the sealing material provided on the outer periphery of the panel. As a result, the upper transparent substrate has an inclination that swells inward from the end. As described above, according to the present invention, since an inclination corresponding to the height of the structure can be formed from the sealing material on the outer periphery of the panel toward the center of the panel, no interference fringes are generated.

  Here, a step is formed on one of the upper transparent substrate and the lower transparent substrate, the same material as the sealing material is provided on the step, and a laminated structure of the same material and the step is used as a structure. Further, the step is formed of the same material having the same thickness as the dot spacer. According to such a configuration, a dot spacer and a step can be manufactured at the same time, and a sealing material and a laminated structure can be formed at the same time. Therefore, a touch panel with good display quality can be provided without increasing man-hours, that is, costs. Moreover, the operativity at the time of a press becomes favorable because the height of a level | step difference with a dot spacer shall be 20 micrometers or less.

  Or you may comprise a structure with the same material with the same thickness as a dot spacer. Thereby, a dot spacer and a structure can be produced at the same time, and a touch panel with good display quality can be provided without increasing man-hours, that is, costs.

  Hereinafter, it demonstrates in detail using an Example. The touch panel methods, materials, formation methods, and the like given in the embodiments are merely examples, and the present invention is not limited to these.

Example 1
FIG. 1 is a schematic diagram partially showing a cross-sectional configuration of the touch panel of the present embodiment. Transparent electrodes 4 are formed in a desired pattern on the upper transparent substrate 2 and the lower transparent substrate 3, respectively. The upper transparent substrate 2 and the side transparent substrate 3 are bonded and fixed by a sealing material 7 provided on the outer periphery of the panel. A spacer 8 and a conductive material 9 are mixed and dispersed in the sealing material 7. The spacer 8 is provided to keep the upper transparent substrate 2 and the lower transparent substrate 3 in a desired gap, and the conductive material 9 electrically connects the transparent electrodes 4 formed on the upper transparent substrate 2 and the lower transparent substrate 3 respectively. It is provided for. A step 6 is formed at a position closer to the center of the panel than the seal material 7. The step 6 is provided to incline the upper transparent substrate 2 from the end of the panel toward the center. A sealing material 7 for adhering and fixing the upper transparent substrate 2 and the lower transparent substrate 3 is also provided on the step 6. The sealing material 7 formed on the outer periphery of the panel or on the step 6 is provided with an opening so that air in the panel can escape during bonding. A dot spacer 5 is formed on the surface of the transparent electrode 4 of the lower transparent substrate 3. In this embodiment, the step 6 is formed with the same material and the same film thickness as the dot spacer 5.

  In this example, a glass substrate having a thickness of 0.2 mm was used for the upper transparent substrate 2, and a glass substrate having a thickness of 1.1 mm was used for the lower transparent substrate 3. The transparent electrode 4 is formed in a desired pattern by photolithography. The transparent electrode 4 is formed of a transparent conductive film called ITO obtained by oxidizing indium containing tin, and a desired resistance value can be set. Since ITO is a low-resistance semiconductor material, its resistance value is 10Ω / □ to 100Ω / □, which is the most general-purpose level. Usually, ITO is formed by a vacuum film forming method called a sputtering method or a vapor deposition method. If necessary, the transparent electrode 4 and a metal wiring (not shown) may be laminated.

  Further, the dot spacer 5 is formed in a desired shape by a photolithography method using a photosensitive resist. The step 6 is formed with the same material and the same film thickness as the dot spacer 5. Subsequently, a seal material 7 for bonding the upper transparent substrate 2 and the lower transparent substrate 3 is screen-printed on the outer periphery of the panel and the step 6. A spacer 8 and a conductive material 9 are mixed and dispersed in the sealing material 7. The sealing material 7 may be a thermosetting adhesive material or a UV curable adhesive. Further, the sealing material 7 may be printed on either the lower transparent substrate 3 or the upper transparent substrate 2. Note that the sealing material 7 formed on the outer periphery of the panel and the sealing material formed on the step 6 may be printed on different transparent substrates. Here, the sealing material 7 may be provided not by screen printing but by application by a dispenser.

  Next, after the upper transparent substrate 2 and the lower transparent substrate 3 are overlapped, the sealing material formed on the outer periphery of the panel and the step 6 is cured while applying pressure and maintaining a predetermined gap. When a plurality of touch panels 1 are laid out on a pair of large transparent substrates, they are separated into individual touch panels 1. Next, the opening of the sealing material 7 formed on the outer periphery of the panel is sealed with a UV curable resin or the like. Subsequently, an FPC 10 or the like is connected to the terminal portion on the lower transparent substrate 3 so that electrical connection with the outside can be performed. An antireflection film 11 is attached to the surface of the upper transparent substrate 2 as necessary.

  FIG. 2 schematically shows a cross-sectional configuration of the liquid crystal display device 14 including the touch panel 1 obtained as described above. The touch panel 1 is bonded to the front surface of the liquid crystal panel 13 with an optical adhesive 12.

(Example 2)
FIG. 3 partially shows a cross-sectional configuration of the touch panel of this example. FIG. 4 schematically shows a cross-sectional configuration of a liquid crystal display device provided with a touch panel. The present embodiment is different from the first embodiment in the structure of the structure formed at a position closer to the center of the touch panel 15 than the seal material 7. Others are the same as those in the first embodiment, and therefore, redundant description is omitted as appropriate.

  As shown, the upper transparent substrate 2 on which the transparent electrode 4 is formed and the lower transparent substrate 3 on which the transparent electrode 4 is formed are bonded and fixed by a sealing material 7 provided on the outer periphery. A dot spacer 5 is formed on the transparent electrode 4 of the lower transparent substrate 3. The dot spacer 5 can be provided in a desired shape by a photolithography method using a photosensitive resist. A step 6 is formed at a position closer to the center of the touch panel 15 than the sealing material 7.

  The step 6 functions as a structure for giving the upper transparent substrate 2 an inclination that swells inward from the end. The step 6 is formed with the same material and the same film thickness as the dot spacer 5. The step 6 is provided to incline the upper transparent substrate 2 from the end of the panel toward the center. Therefore, the step 6 is higher than the particle size of the spacer 8 mixed and dispersed in the sealing material 7. When the step 6 is formed on the entire outer periphery of the panel, it is preferable to provide an opening in the step so that air in the panel can escape during bonding.

  Such a touch panel 15 is bonded to, for example, the front surface of the liquid crystal panel 13 with the optical adhesive 12 or the like to obtain the liquid crystal display device 16.

  In each of the above-described embodiments, the dot spacer 5 and the step 6 are provided on the lower transparent substrate 3, but these may be provided on the upper transparent substrate 2.

  The present invention can be applied to a touch panel in which a pair of substrates are joined with a gap.

DESCRIPTION OF SYMBOLS 1, 15 Touch panel 2 Upper transparent substrate 3 Lower transparent substrate 4 Transparent electrode 5 Dot spacer 6 Step 7 Seal material 8 Spacer 9 Conductive material 10 FPC
11 Antireflection film 12 Optical adhesive 13 Liquid crystal panel

Claims (7)

An upper transparent substrate on which an upper transparent electrode is formed;
While facing the upper transparent substrate with a gap, a lower transparent substrate on which a lower transparent electrode is formed, and
A sealing material for bonding the upper transparent substrate and the lower transparent substrate;
A dot spacer formed on the inner surface of one of the upper transparent substrate and the lower transparent substrate;
A touch panel, wherein a structure thicker than the sealing material is provided at a position inside the sealing material so that the upper transparent substrate has an inclination that swells inward from an end portion.   2. The touch panel according to claim 1, wherein the structure has a structure in which a step formed on one of the upper transparent substrate and the lower transparent substrate and the same material as the sealing material are stacked. .   The touch panel according to claim 2, wherein the step is made of the same material having the same thickness as the dot spacer.   The touch panel according to claim 2, wherein the dot spacer and the step are formed with a height of 20 μm or less.   The touch panel according to claim 1, wherein the structure is made of the same material having the same thickness as the dot spacer.   The touch panel as set forth in claim 5, wherein spacers for adjusting the gap are dispersed in the sealing material, and the thickness of the structure is larger than the particle diameter of the spacers.   A display device, wherein the touch panel having the configuration described in any one of claims 1 to 6 is bonded to a display panel with an optical adhesive.

Images