Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Reexamination Certificate
1999-02-18
2001-04-24
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
C250S231160
Reexamination Certificate
active
06222181
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a position measuring apparatus which can be applied to all fields requiring precise positional measurement.
BACKGROUND ART
The measurement of precise distance and length (hereinafter generally called distance) is important in various fields and various methods are practically used. To obtain distance between two points, it is required to precisely measure the relative positions of the two points. For general means used for measuring distance or a relative position, calipers, a micrometer, a dial gauge, a magnetic scale, a laser length measuring machine, a microscope and others are known. As machining means and an object to be machined are required to be precisely positioned in many fields such as the fields of semiconductor integrated circuit technology and a machine tool, the high precision measurement of distance or a relative position is required as the precondition.
For example, in the field of manufacturing semiconductor devices, the precise measurement of distance for positioning is required in many steps from the formation of devices on a semiconductor wafer to the dicing, wire bonding and packaging of a chip. The technique of pattern recognition may be used for a method for positioning in dicing. In the case of an automated machine tool, the precise detection of a relative position between the tool and a work to be processed is also essential and positioning is executed by a method of detecting the movement distance of a work to be processed based upon, for example, a signal from an encoder and the like and numerically controlling the position of the tool and the work to be processed based upon the detected movement distance.
However, there is a problem that though a conventional type position measuring apparatus is suitable for measuring a position in a specific field, it is difficult to immediately use it for measuring a position in the other field. The precision is also limited.
The present invention is made from the above circumstances and the object is to provide a position measuring apparatus by which high precision positional measurement in various fields is enabled on a simple principle.
DISCLOSURE OF THE INVENTION
A first invention for achieving the above object is characterized in that it is provided with light receiving means (p=q×r) constituted by dividing total p pieces of light receiving devices linearly arranged at an equal interval into r pieces groups including q pieces of light receiving devices in a group, light source means which can be moved along the above light receiving means in the direction of the arrangement of the above light receiving devices for radiating light to the a plurality of the light receiving devices of the light receiving means, first position specifying means for specifying the position of the above light source means using the length of the above one group as the unit and second position specifying means for obtaining the periodic function from q pieces of signals obtained by adding the output of the corresponding light receiving devices in each of the r pieces of groups and determining the position of the above light source means in the range of the length of one group by calculating the phase of this periodic function and in that the relative position of the above light source means for the above light receiving means is measured.
A second invention for achieving the above object is characterized in that it is provided with light receiving means constituted by dividing total p pieces of light receiving devices linearly arranged at an equal interval into r groups each of which includes q pieces of light receiving devices(p=q×r), light source means in which a plurality of light sources arranged at an interval equal to an interval between the groups of the above light receiving devices respectively emit light to the light receiving means at predetermined intensity distribution and which is opposite to the light receiving means and can be generally moved in parallel along the direction in which the light receiving devices of the above light receiving means are arranged, first position specifying means for specifying the position of the above light source means in units of the length of the above one group and second position specifying means for obtaining the periodic function from q pieces of signals obtained by adding the output of the corresponding light receiving devices in each of the r pieces of groups and determining the position of the light source means in the range of the length of one group by calculating the phase of this periodic function and in that the relative position of the above light source means for the above light receiving means is measured.
A third invention for achieving the above object is characterized in that it is provided with light receiving means constituted by dividing a plurality of light receiving devices linearly arranged at an equal interval into groups so that i pieces of light receiving devices are included in each group, light source means in which j (j≠i) pieces of light sources for emitting light to the above light receiving means in a predetermined range are included per distance equal to the dimension of one group of the above light receiving devices and which can be generally moved in parallel to the light receiving devices of the light receiving means, first position specifying means for specifying the relative position of the above light source means and the above light receiving means using distance between light sources of the light source means as the unit and second position specifying means for calculating the relative position of the above light receiving means and the above light source means in the range of the above distance between light sources by adding signals output from the light receiving devices arranged in the corresponding position in the respective groups when light receiving devices receive light from light sources, obtaining the periodic function from the i pieces of adding results and calculating the phase of this periodic function and in that the relative position of the light source means for the light receiving means is measured.
A fourth invention for achieving the above object is characterized in that it is provided with light receiving means (p=q×r) constituted by dividing total p pieces of light receiving devices linearly arranged at an equal interval into r pieces of groups including q pieces of light receiving devices in each group, optical interference means arranged opposite to the light receiving face of the above light receiving means so that it can be moved in parallel in the direction of the arrangement of the above light receiving devices for generating an interference fringe due to interference of light which is incident on the above light receiving face and changing the intensity of light at a repetition period equal to the length of one group of the above light receiving means on the above light receiving device, first position specifying means for specifying the position of the above optical interference means using the above group as the unit and second position specifying means for obtaining the periodic function from q pieces of signals obtained by adding signals output from the corresponding light receiving device in each of the r pieces groups when light is incident from the above optical interference means and determining the position of the above optical interference means in the range of the length of one group by calculating the phase of this periodic function and in that the relative position of the optical interference means for the above light receiving means is measured.
A fifth invention for achieving the above object is characterized in that it is provided with light receiving means constituted by dividing a plurality of light receiving devices linearly arranged at an equal interval into groups so that i pieces of light receiving devices are included in each group, optical interference means arranged opposite to the light receiving fac
Le Que T.
Rabin & Champagne, P.C.
Seft Development Laboratory Co., Ltd.
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