Touch panel

a technology of touch panel and touch screen, applied in the field of touch panel, can solve the problems of significant reduction, difficult to detect the position indicated, and the signal ratio, and achieve the effect of reducing the effect of external light on sensitivity and accuracy

Inactive Publication Date: 2013-01-15
CANON KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0012]The present invention has been made in consideration of the above situation, and has as its object to reduce the effect of external light on sensitivity and accuracy in a touch panel.

Problems solved by technology

More specifically, background components of signals proportional to the product of the width and length of the face constituting the touch panel appear, the ratio of the signal to be detected to the background component (hereinafter, this index is referred to as contrast) is significantly decreased, and it becomes difficult to detect the position indicated.
Further, there is fundamentally an essential problem that the display disposed under the panel always has to operate in a scanning manner, and displays that operate in a non-scanning manner are thus inoperative because the operating principle is not able to be applied.
Moreover, for the touch panel in Japanese Patent Laid-Open No. 2000-259347, indicating devices which are not dedicated indicating devices, such as, for example, a finger, are not be able to be used.
Further, the presence of external light further reduces the essentially already low contrast, thus making it more difficult to detect the position indicated.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

first embodiment

[0029]FIG. 1 is a diagram illustrating an example of the configuration of a touch panel in a first embodiment of the present invention, wherein reference numerals 1a, 1b, and 1c respectively denote a top view, a schematic cross-sectional view (X section) along the line a-a′, and a schematic cross-sectional view (Y section) along the line b-b′. In FIG. 1, reference numeral 101 denotes a light guide plate for detection which is disposed for detection. As for the shape of the light guide plate, light guide plates in parallel plate shape are preferably used. The light guide plate functions as a light guide which has a first face for detecting the position of an object in contact therewith and a second face opposite the first face.

[0030]Reference numeral 102 denotes a display panel in which display elements are two-dimensionally arranged. The light guide plate 101 can also serve as a cover for the display panel 102, when the light guide plate 101 for detection is disposed such that the r...

second embodiment

[0040]FIG. 3 is a diagram illustrating an example of the configuration of a touch panel in a second embodiment of the present invention, where reference numerals 3a, 3b, and 3c respectively denote a top view, a schematic cross-sectional view (X section) along the line a-a′, and a schematic cross-sectional view (Y section) along the line b-b′. It is to be noted that the same elements as those in FIG. 1 are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0041]In FIG. 3, reference numeral 301 denotes a liquid crystal display panel in the second embodiment, which is composed of a polarization plate 302, a liquid crystal unit 303, and a polarization plate 304. The liquid crystal display panel 301 includes, on the rear side thereof, a plurality of light emitting elements which emit visible light, and as backlight, light sources 305 for display (first light sources) arranged at constant intervals over the entire liquid crystal display panel 301. The liquid...

third embodiment

[0050]FIG. 4 is a diagram illustrating an example of the configuration of a touch panel in a third embodiment of the present invention, where reference numerals 4a, 4b, and 4c respectively denote a top view, a schematic cross-sectional view (X section) along the line a-a′, and a schematic cross-sectional view (Y section) along the line b-b′. It is to be noted that the same elements as those in FIGS. 1 and 3 are denoted by the same reference numerals, and descriptions thereof will be omitted. The third embodiment is different from the second embodiment described above in the configurations of the light sources for display and the light sources for detection. The configurations of the light sources for display and the light sources for detection will be described in detail below.

[0051]Reference numeral 401 denotes a light emitting element for display (first light emitting element) to be used for display, and a light emitting element 402 for detection (second light emitting element) is...

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PUM

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Abstract

A touch panel includes a light guide including a first face for detecting the position of an object in contact therewith and a second face opposite the first face, and a line sensor for receiving light emitted from a side face of the light guide plate, wherein, of light irradiated from the second face side, the light guide guides toward the side face the portion of light reflected by the object.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a touch panel, and more particularly, to an optical touch panel.[0003]2. Description of the Related Art[0004]Touch panels are now used which can give an instruction to an apparatus when an interface image projected onto a display is touched. While there are a variety of specific operating principles for touch panels, touch panels are requested which have sufficient mechanical strength and high transmittance. In response to such requests, in order to provide mechanical strength, various optical touch panels have been proposed which use an optical detection mechanism. Further, in optical touch panels, in order to reduce the effect of contamination of the detection mechanism, structures have been proposed for preventing light emitting surfaces for use in detection and detection sensor light receiving surfaces from being exposed on the surface.[0005]FIG. 12 is a diagram illustrating an optic...

Claims

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Application Information

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Patent Type & AuthorityPatents(United States)
IPC IPC(8): G06F3/041
InventorYAMASHITA, YUICHIROJOHNSON, MICHIKOHASEGAWA, SHIN
OwnerCANON KK