Title:
FOREIGN MATTER INSPECTING DEVICE FOR LIQUID CRYSTAL SUBSTRATE
Document Type and Number:
Japanese Patent JP3266217
Kind Code:
B2
Abstract:
PURPOSE: To detect a foreign matter with scattered light as for the liquid crystal substrate which has many rectangular patterns with large steps by separating and detecting the scattered light by sensors and deciding the foreign matter when respective detection levels are nearly equal.
CONSTITUTION: The pattern of pixels is irradiated with the laser beam A from an irradiation system 2 with wavelength λ1 and the laser beam 3 from an irradiation system 3 with wavelength λ2 opposite at an angle of 45° respectively. Consequently, scattered light A+B of the laser beams A and B is made incident on the objective 4a of an objective optical system 4 as for the foreign matter 10. The outputs of the sensors 4g and 4h, therefore, become almost equal, and their values when exceeding certain values larger than threshold values THa and THb are amplified by amplifiers 6a and 6b respectively and inputted to a dividing circuit 6c. At this time, the division result of the dividing circuit 6c between the input signals is almost '1'. Then a foreign matter deciding circuit 6d decides the foreign body when the output of the dividing circuit 6c is '1' nearly '1'.
Inventors:
Hidekazu Chikamatsu
Application Number:
JP17113393A
Publication Date:
March 18, 2002
Filing Date:
June 17, 1993
Export Citation:
Assignee:
Hitachi Electronics Engineering Co., Ltd.
International Classes:
G01M11/00; G01N21/88; G01N21/94; G01N21/956; G02F1/13; G02F1/1333; G02F1/136; G02F1/1368; (IPC1-7): G02F1/13; G01M11/00; G01N21/88
Domestic Patent References:
| JP6270739A | ||||
| JP6219739A | ||||
| JP4245660A | ||||
| JP587740A | ||||
| JP4324653A |
Attorney, Agent or Firm:
Kajiyama Bozen (1 person outside)