Radiant energy – Photocells; circuits and apparatus – Photocell controlled circuit
Reexamination Certificate
1998-06-29
2001-03-13
Lee, John R. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Photocell controlled circuit
C250S221000, C327S515000
Reexamination Certificate
active
06201233
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a position detection sensor, and a position detection device and a position input device incorporated with the position detection element.
2. Description of Related Art
Various conventional elements, devices, and methods used for detecting optically the position and motion of an object have been proposed and commercialized heretofore. In one example of a light detection element, a light detection layer and a resistance layer having an even resistance value are laminated to form a prescribed length of a laminate and an output electrode is provided on both ends thereof. In the light detection element, for example, a laser beam namely a light source is irradiated onto a light detection element, the photoelectric current generated thereby is measured at both ends to determine the laser irradiated position on the light detection element based on two current values. The above-mentioned light detection element may be formed in planer shape to detect the two-dimensional position or motion of an object.
However, in the above-mentioned method, it is required that an object must have a light source, and the light must be focused accurately on a light detection element. Therefore it is impossible for a light detection element to extract a moving object out of unspecified objects and to measure the position.
In another example of a method for detecting the position and motion of an object, an image pick-up element such as an area sensor of CCD (Charge Coupled Device) and an image memory are utilized. In this method, image information from an image pick-up element is stored in an image memory every prescribed time interval, and changed points of the image are extracted from a plurality of stored image information to detect the position and motion.
According to the method which utilizes CCD area sensor, moving objects are extracted from non-specific objects, and the position and motion are detected. However, a detection device which utilizes this method is inevitably large, and a memory having a large capacity and a high-speed operation CPU are required because of large image information to be processed, and such requirements makes disadvantageously the detection system very expensive.
It has been difficult to construct a position input device, for example, a pointing device such as a mouse because of the problem of the above-mentioned device.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a position detection element, a position detection device, and a position input device having a simple and inexpensive structure for detecting the position and motion of an object.
The present invention is accomplished in view of the above-mentioned problem, a position detection element is provided with a light detection means comprising a plurality of light detection elements arranged on a straight line, the first memory means for storing detection signal of the light detection means, the second memory means for storing detection signal of the light detection means, the first switch means for connecting any one of the first memory means and the second memory means to the light detection means, the difference detection means for detecting the difference between signals stored in memory elements corresponding respectively to the first memory means and the second memory means, and the second switch means for switching successively the memory element corresponding respectively to the first memory means and the second memory means.
A memory means for storing analog quantity is used as the first memory means and the second memory means respectively.
The light detection means comprises a MOS type light detection element, and the first memory means and the second memory means comprise respectively a capacitive element.
A position detection element is provided with a light detection means comprising a plurality of light detection elements arranged on a straight line, the first charge storage transfer means for storing and transferring detection signal of the light detection means, the second charge storage transfer means for storing and transferring detection signal of the light detection means, the first switch means for inputting detection signal of the light detection means to the first charge storage transfer means, the second switch means for inputting detection signal of the light detection means to the second charge storage transfer means, and a difference detection means for detecting the difference between signals stored in charge storage elements corresponding respectively to the first charge storage transfer means and the second charge storage transfer means.
The first charge storage transfer means and the charge storage transfer means comprise respectively a CCD.
A position detection device provided with any one of the above-mentioned position detection elements, a means for recognizing a moving object based on the output from the position detection element, and a means for calculating the moving position of the moving object based on the output from the position detection element.
The above-mentioned problem is solved by using a position input device provided with two of any one of the above-mentioned position detection elements arranged in orthogonal two directions, a means for calculating the respective moving quantity of the position detection elements based on the output from the respective position detection elements, and a means for pointing a position on a screen of a display device based on the obtained moving quantity of the respective position detection elements arranged in the orthogonal two directions.
By applying the element structure of the present invention, a position detection element which is capable of extracting a moving object out of unspecified objects, and detecting the position and motion of the object without using a dedicated light source is realized. Position detection devices and position input devices which are compact, inexpensive, and easy to use are provided by applying position detection elements of the present invention.
REFERENCES:
patent: 5288993 (1994-02-01), Bidiville et al.
patent: 5949483 (1999-09-01), Fossum et al.
Lee John R.
Pyo Kevin
Sonnenschein, Nath & Rosentahl
Sony Corporation
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