Radiant energy – Photocells; circuits and apparatus – Photocell controls its own optical systems
Patent
1991-12-04
1993-05-18
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Photocell controls its own optical systems
359249, G01J 120
Patent
active
052123740
ABSTRACT:
An imaging method creates a two-dimensional image of a voltage distribution or a capacitance distribution across a surface of a substrate under test using an electro-optic modulator which is positioned and biased with respect to the surface of the substrate. The method involves a first coarse offsite calibrating step to compensate for nonuniformities in the light emerging from the modulator. Then, for each successive portion of the substrate over which the modulator is to detect characteristics of the substrate, the system undergoes a modulator relocating step, a modulator levelling step, a modulator gapping step, a fine onsite calibrating step, and a measuring step. An apparatus is disclosed for levelling the bottom surface of a modulator into a substantially coplanar spacial relationship with a portion of top surface of the underlying substrate being tested monitors light emerging from at least three regions on the top surface of the modulator in order to determine the relative distances of three corresponding regions of the bottom surface of the modulator from the underlying top surface of the substrate being tested. In one embodiment, three transducers are used to control the spacial orientation of the modulator. The method and apparatus see special application in detecting defects in LCD display panels.
REFERENCES:
patent: 4019807 (1977-04-01), Boswell et al.
patent: 4634853 (1987-01-01), Kanamaru
Choi Hee-June
Henley Francois J.
Liu Ying-Moh
Miller Michael J.
Speedy James C.
Nelms David C.
Photon Dynamics, Inc.
LandOfFree
Method and apparatus for positioning and biasing an electro-opti 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 positioning and biasing an electro-opti, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for positioning and biasing an electro-opti will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-806138