Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Reexamination Certificate
1999-05-26
2002-08-20
Luu, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
C345S179000, C178S019050
Reexamination Certificate
active
06437314
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an electronic board as a device for inputting information into a computer, to a coordinate input system, and to a coordinate input pen used therewith employing an infrared (hereinafter, simply referred to as “IR”) detection system.
BACKGROUND OF THE INVENTION
An electronic board is one type of devices for inputting information into a computer. Specifically, the electronic board recognizes the location or the path on the board pointed or traced by a coordinate input pen as coordinate data, based on which a display image is output from a computer and projected onto the electronic board (screen) with a front or a rear projector.
There are various electronic board systems such as an electromagnetic induction system, a laser scan system, an ultrasonic system, a pressure sensitive system and the like. According to the electromagnetic induction system, a position of a coordinate input pen is detected by sensing wires wired throughout an electronic board which detects ac (alternating current) magnetic field generated by the coordinate input pen. The laser scanning system refers to a method in which a position of a coordinate input pen is detected with IR beams scanning parallel to a surface of a board, or to a method in which two laser scanners are employed to scan a path traced with a coordinate input pen. According to the ultrasonic system, an ultrasonic pulse is oscillated by a coordinate input pen. Then, the position of the coordinate input pen is calculated based on the time lags between the actual oscillation of the ultrasonic pulse and the detection of the oscillated ultrasonic pulse by ultrasonic sensors peripherally placed around the board. According to the pressure sensitive system, a position pressed by a coordinate input pen is detected with a pressure sensitive element provided over the entire surface of the board.
Except for the laser scanning system, the above-described systems have the following problems. The electromagnetic induction system or the pressure sensitive system cannot be used with a transparent electronic board, and a large-sized electronic board incorporating these systems would be unpractical and cost mindless to produce. The pressure sensitive system does not recognize signals corresponding to those of mouse buttons (e.g., double-click and right-click signals). The ultrasonic system is limited in accuracy and is easily affected by noise.
According to the laser scanning system, two laterally provided (i.e., at right and left) laser scanners scan over a large-sized display such as a screen to acquire the position of the coordinate input pen based on light reflected off the pen. Specifically, a reflective face of the tip portion of the pen reflects the lateral laser beams. The reflected beams are then sensed and processed by the two laser scanners, thereby determining the position of the pen. Alternatively, the tip portion of the coordinate input pen is equipped with an optical sensor which directly processes the acquired beam signals to determine the position of the pen. However, according to such structures, distortion or deformation of the display panel (or the screen), a tilt of the pen upon use, or the like may interfere with accurate reflection or receiving of the laser beams. As a result, the path of the pen may not always be accurately reproduced on the display panel (or the screen).
SUMMARY OF THE INVENTION
With regard to the above-described problems, the object of the present invention is to provide a coordinate input system and a coordinate input pen employing an IR detection system, which allow steady detection of the position of the pen even under the circumstances where a display panel is distorted or deformed, or where the coordinate input pen is tilted. The present invention also aims at providing an electronic board and an electronic board system for steadily displaying the path of the coordinate input pen.
Thus, instead of employing a system where two IR scanning beams that reflected off the coordinate input pen are detected or where light is directly detected with a light-receiving element provided at the tip portion of the coordinate input pen, the present invention employs a system where IR scanning beams scatter and perpendicularly propagate within a coordinate input pen to be detected. In order to ensure the detection of the IR scanning beams, a conical IR scattering member is provided at the end of the coordinate input pen. This scattering member only detects beams that are scattered generally perpendicular to the incident direction of the beam, i.e., beams that propagates along the axis of the pen. This detecting portion of the coordinate input pen is made longer along the axis of the pen so as to allow the detection of the incident beam even if there is distortion of a display panel (e.g., a screen), tilt of the coordinate input pen, or the like, thereby enabling accurate reproduction of the path of the coordinate input pen. A part or the whole tip portion of the pen may be made to light up in response to an IR scanning beam detection signal so that the user will always know the status of IR beam detection by the coordinate input pen, rendering the pen more manageable.
In one aspect of the invention, a coordinate input pen specifies and outputs coordinates of the pen by detecting two IR beams that are emitted from two separate positions for pivotally scanning over a plane parallel to a surface of a display panel. The coordinate input pen includes: a shaft portion; a transparent conical light scattering member with a rough surface placed at the end of the shaft portion; and a light receiving element for detecting an IR beam scattered within the light scattering member. The coordinate input pen of the invention is capable of outputting coordinates even when the tip of the pen is not touching the electronic board, as long as the tip is close enough to the board to cross with the two IR scanning beams.
Preferably, the shaft portion is provided with a displaying member which visually displays the status of receiving the IR beam. This displaying member may be used to visualize the status of receiving the IR beam as either normal (where the coordinate input pen is alternately receiving the two IR scanning beams) or abnormal (where only one of the two IR scanning beams is continuously being received).
According to another embodiment, the coordinate input pen may be provided with functions of producing signals corresponding to left click, right click and double click of a mouse or signals corresponding to an enter key of a keyboard of a personal computer (hereinafter, simply referred to as a “PC”). This may be realized, for example, by providing the shaft portion of the pen with buttons having functions corresponding to such mouse buttons or such keys.
According to still another embodiment of the invention, the coordinate input pen may include a writing tool for leaving a path written on the display panel while outputting coordinates of the pen. The writing tool may be, for example, a water marker, a chalk, a pencil, or a crayon.
The coordinate input pen of the invention may be used as a coordinate input device of an electronic board employing an IR detection system. In this case, the system is designed such that signals indicating beam rotation angles of two rotary mirrors that are separately provided in the electronic board and a beam detection signal from the coordinate input pen are transmitted to a signal controller of the electronic board either wirelessly or via a wire. The signal controller processes these signals to determine the position of the coordinate input pen and renders a path of the pen to be displayed on a display panel (e.g., a screen).
In another aspect of the invention, a coordinate input system includes: a first IR scanning beam generator and a second IR scanning beam generator which alternately generate IR scanning beams; a first reference sensor for generating a first reference signal upon detecting an IR scanning beam generated by the first IR scanning beam
Amemiya Sueo
Miyauchi Naoki
Namiki Jun
Takeuchi Ichirou
Usuda Yutaka
Fish & Richardson P.C.
Hitachi Software Engineering Co. Ltd.
Lun Thanh X.
Luu Que T.
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