Radiant energy – Photocells; circuits and apparatus – With circuit for evaluating a web – strand – strip – or sheet
Reexamination Certificate
2001-10-31
2003-12-02
Bruce, David V. (Department: 2882)
Radiant energy
Photocells; circuits and apparatus
With circuit for evaluating a web, strand, strip, or sheet
C250S559390, C356S505000
Reexamination Certificate
active
06657218
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2001-323732, filed on Oct. 22, 2001, entitled “METHOD AND APPARATUS FOR MEASURING GAP, METHOD AND APPARATUS FOR MEASURING SHAPE AND METHOD FOR MANUFACTURING LIQUID CRYSTAL DEVICE”. The contents of that application are incorporated herein by reference in their entirely.
BACKGROUND OF THE INVENTION
1. Technical Field to Which the Invention Belongs
The present invention relates to technology for measuring a clearance (gap) between members or a shape thereof by utilizing interference of light.
2. Description of the Related Art
Conventionally, as an apparatus for measuring a gap in a light transmission member such as a liquid crystal cell, for example, there has been employed such a gap measuring apparatus as shown in a configuration diagram in FIG.
19
. This gap measuring apparatus utilizes a phenomenon that refractive waves from a top face and a bottom face of a gap in actual thickness “d” (refraction index of a medium is defined as “n”) illuminated by an objective lens of a microscope via a half mirror return with a second phase difference, and these two lights pass through a Wollaston prism and polarizing plates A and P, thereby producing an interference fringe. That is, a peak gap “y” between an interference fringe caused by the refractive lights of the top face and bottom face and an interference fringe in cross line on the refractive wave face between the top face and bottom face is measured, whereby a value of the gap “d” is obtained by the following formula (1):
y=nd
/(
n
e
−n
o
)tan &thgr; (1)
where &thgr; denotes a Wollaston prism angle, and n
e
and n
o
each denote a refractive index of the Wollaston prism angle.
However, the above described conventional gap measuring instrument is intended for measuring one point of an object. In order to measure a gap distribution in a predetermined section, measurement must be repeated while such an object is being moved, which is complicated in work and requires much time.
SUMMARY OF THE INVENTION
The present invention in accomplished taking the foregoing problem into consideration. Accordingly, an object of the invention is to provide a method and apparatus capable of measuring a gap between objects or a shape of such an object with a high speed and high precision and a method for effectively manufacturing a liquid crystal device.
To achieve the foregoing object, the present invention adopts the following structures.
(1) A gap measuring method characterized by comprising the steps of:
applying a plurality of color lights to a member provided with a gap, to produce color interference fringes;
obtaining respective intensities of the color lights in the images of the interference fringes taken by a color camera, at each of predetermined positions of each image, so as to compute an actual ratio among (or of) the obtained intensities of the color lights for each of the predetermined positions; and
obtaining gap values of a plurality of points of the gap provided in the member, based on said actual ratio and theoretical ratios each of which is computed based on intensities of said color lights in an image, correspondingly to each of preliminarily set gap values.
(2) A gap measuring method in (1), characterized in that the interference fringe is obtained by using transmitted light through the member.
(3) A gap measuring method in (1), characterized in that the interference fringe is obtained by using reflected light from the member.
(4) A gap measuring method in any one of (2)~(3), characterized in that a composite light including said plurality of color lights is applied to the member.
(5) A gap measuring method in any one of (2)~(3), characterized in that white light including said plurality of color lights is applied to the member, and that a filter is provided for transmitting the plurality of color light to the color camera.
(6) A gap measuring method in any one of (1)~(5), characterized in that the intensities of the each color light in the images taken up by the color camera are corrected in consideration of a variable element for the each color light.
(7) A gap measuring method in any one of (1)~(6), characterized in that each of the images is composed of a plurality of pixels, and gap measurement is carried out for each pixel.
(8) A shape measuring method utilizing the gap measuring method in (1)~(7), characterized in that one of members defining a gap is made into a plate-shaped element with a flat surface to effect the measurement, and the shape of the other member defining the gap is determined on the basis of the thus obtained gap measurement value.
(9) A gap measuring apparatus characterized by comprising:
a light source for applying a plurality of different color lights to an object to be measured having light transmission properties;
a color camera for picking up images of interference fringes formed by the light transmitted through the object to be measured;
an image memory for storing images picked up by the color camera;
computing means for obtaining respective intensities of the color lights in the images at each of predetermined positions of each image, so as to compute an actual ratio among (or of) the obtained intensities of the color lights for each of the predetermined positions;
a reference data memory for storing theoretical ratios among (or of) intensities of said color lights in an image, correspondingly to each of preliminarily set gap values; and
gap value comparing/determining means for determining gap values of a plurality of points of a gap provided in the object to be measured according to the actual ratio and the theoretical ratios.
(10) A gap measuring apparatus characterized by comprising:
a light source for applying light to an object to be measured having light transmission properties;
a color camera for picking up images of interference fringes formed by the light transmitted through the object to be measured;
a filter for transmitting a plurality of different color lights to the color camera;
an image memory for storing images picked up by the color camera;
computing means for obtaining respective intensities of the color lights in the images at each of predetermined positions of each image to compute an actual ratio among (or of) the obtained intensities of the color lights for each of the predetermined positions;
a reference data memory for storing theoretical ratios among (or of) intensities of said color lights in an image correspondingly to each of preliminarily set gap values; and
gap value comparing/determining means for determining gap values of a plurality of points of a gap provided in the object to be measured according to the actual ratio and the theoretical ratios.
(11) A gap measuring apparatus characterized by comprising:
a light source for emitting a plurality of different color lights;
a color camera for picking up images of light interference fringes;
optical means for directing the lights from the light source toward an object to be measured and directing reflected lights thereof from the object to be measured toward the color camera;
an image memory for storing images of the interference fringe formed by the lights from the optical means and picked up by the color camera;
computing means for obtaining respective intensities of the color lights in the images at each of predetermined positions of each image, so as to compute an actual ratio among (or of) the obtained intensities of the color lights for each of the predetermined positions;
a reference data memory for storing theoretical ratios among (or of) intensities of said color lights in an image, correspondingly to each of preliminarily set gap values; and
gap value comparing/determining means for determining gap values of a plurality of points of a gap provided in the object to be measured according to the actual ratio and the theoretical ratios.
(12) A gap measuring apparatus characterized by comprising:
a light source for emitting light;
a color camera for pick
Bruce David V.
Harness & Dickey & Pierce P.L.C.
Seiko Epson Corporation
Song Hoon
LandOfFree
Method and apparatus for measuring gap, method and apparatus... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for measuring gap, method and apparatus..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for measuring gap, method and apparatus... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3155012