Computer graphics processing and selective visual display system – Display peripheral interface input device – Touch panel
Reexamination Certificate
1998-04-17
2002-11-12
Chow, Dennis-Doon (Department: 2675)
Computer graphics processing and selective visual display system
Display peripheral interface input device
Touch panel
C345S173000, C345S176000
Reexamination Certificate
active
06480187
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical scanning-type touch panel which inputs information thereinto by touching a plane such as a display screen of a computer which is specified as a section to be touched by means of an indicator.
2. Description of the Prior Art
In the case where information displayed on a screen of a personal computer or the like is inputted by a touching method, it is necessary to detect a touched position (indicated position) on the display screen accurately. As a method of detecting the indicated position on a display screen, “Carol method” (U.S. Pat. No. 4,267,443) is known. According to this method, an optical matrix is structured on a front surface of a display screen by arranging light emitting elements and light receiving elements oppositely in a frame on the front surface of the display screen, and a position where a light is cut off by touch of a finger or pen is detected. According to this method, a high S/N ratio is obtained, so the method can be applied to a large-sized display apparatus, but since resolution of detection is in proportion to arrangement intervals between the light emitting elements and light receiving elements, it is necessary for high resolution of detection to reduce the arrangement intervals. Therefore, in order to detect a touched position accurately even in the case where a large-sized screen is touched by a thin material such as a point of a pen, there arises a problem that a number of light emitting elements and light receiving elements to be arranged is increased and, thus, the arrangement becomes large, and signal processing becomes complicated.
In addition, another optical position detecting method is disclosed in Japanese Patent Application Laid-Open No. 57-211637/1982. According to this method, a focused light such as a laser beam is scanned angularly from the outside of a display screen, an angle where a special pen exists is obtained from two timings of reflected lights from the special pen having a reflector, and the obtained angle is applied to the triangulation principle so that a coordinate of the position is detected by calculation. This method can reduce a number of parts greatly, and can provides high resolution. However, there is a problem of operability such that a special reflection pen should be used, and the position of a finger, an arbitrary pen, etc., cannot be detected.
Still another optical position detecting method is suggested in Japanese Patent Application Laid-Open No. 62-5428/1987. According to this method, an light retro-reflector is arranged in frames on both sides of a display screen, a return light from the light retro-reflector of a light beam scanned angularly is detected, an angle where a finger or pen exists is obtained from timing that the light beam is cut off by the finger or pen, and a coordinate of the position is detected according to the triangulation principle to which the obtained angle is applied. In this method, detecting accuracy can be maintained with a small number of parts, and the position of a finger, arbitrary pen, etc., can be detected.
However, in the method disclosed in Japanese Patent Application Laid-Open No. 62-5428/1987, the detected touched position is occasionally deviated from an actually touched position due to an influence of a size or position of the indicator. Moreover, in the case where a finger-touched position is detected, when the screen is touched by parts of the hand other than this finger or an elbow touches, there arises a problem that a position which is touched by the parts of the hand other than the finger or an elbow is detected falsely and the position of the finger cannot be specified.
In addition, in the conventional methods, a light emitting element which emits a scanning light is frequently arranged so that an optic axis of the light emitted by the light emitting element is parallel with a scanning surface, and a light receiving element which receives a reflected scanning light is frequently arranged so that a direction of the received light is parallel with the scanning surface. For this reason, the light send/receive member becomes comparatively large, and this frequently disturbs the miniaturization of the whole apparatus.
Further, the display screen is generally rectangular and a scanning region is designed according to the display screen, and in this case when the arrangement is such that a light emitting element, light receiving element, light scanning element, etc., are arranged parallel with each other at the edge sides of the display screen so that the apparatus can be miniaturized. However, in the case of this arrangement, there arises a problem that a scanning light by the light scanning element is blocked by the light emitting element, light receiving element, etc., and thus a sufficient scanning angle cannot be obtained.
In the conventional methods, an off-set voltage is changed because of an influence of sensitivity caused by a change in temperature, etc., of the light receiving element, and thus there is a possibility that accurate measurement cannot be made.
In addition, in the conventional methods, the time required for the light receiving element receiving a reflected light in scanning once is varied according to scattering of a rotating speed of a polygon mirror, etc., of respective apparatuses, but it is troublesome that manufactures adjust individual apparatuses, and they cannot cope with fluctuations after shipment.
Further, in the conventional methods, in the case where two or more indicators exist on a scanning surface, there arises a problem that their positions cannot be detected accurately.
BRIEF SUMMARY OF THE INVENTION
One object of the present invention is to provide an optical scanning-type touch panel or an optical scanning-type input device which is capable of detecting a position of an indicator for indicating on a plane specified as an object to be touched (hereinafter called as coordinate surface in short) accurately by judging a size of the indicator.
Another object of the present invention is to provide an optical scanning-type touch panel in which when the position is indicated by a finger or pen, if a hand or elbow touches a display screen, its detected position is made to be invalid, an accurate position indicated by the finger or pen can be detected.
Still another object of the present invention is to provide an optical scanning-type touch panel in which scanning lights by an optical scanning element can be prevented from being cut off by a light emitting element, a light receiving element or the like by arranging the light receiving element and light scanning element farther from the edge sides of a rectangular coordinate surface than the light emitting element, and a sufficient scanning angle can be obtained.
Still another object of the present invention is to provide an optical scanning-type touch panel in which a light emitting element for emitting a scanning light is arranged so that an optic axis of the emitted light intersects a scanning surface and a light receiving element for receiving reflected scanning light is arranged so that directivity of the received light intersects the scanning surface, and thus a light send/receive part can be miniaturized and further the whole of the apparatus can be miniaturized.
Still another object of the present invention is to provide an optical scanning-type touch panel in which a defect of faults of an optical isolator in the case of using a half mirror is eliminated.
Still another object of the present invention is to provide an optical scanning-type touch panel in which an influence of a change in sensitivity due to a change in temperature of light receiving element is eliminated so that accurate measurement can be made.
Still another object of the present invention is to provide an optical scanning-type touch panel which is capable of automatically correcting scattering of the time when a light receiving element receives a reflected light at scanning once in respective apparatuses, and capabl
Abe Fumitaka
Iida Atsuo
Nakazawa Fumihiko
Sano Satoshi
Yamaguchi Nobuyasu
Chow Dennis-Doon
Nelson Alecia D.
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