Patent US5204617A successfully refreshed from Google Patents.
US5204617A
Expired / Lapsed
US
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Liquid crystal panel inspection method
Assignee: Sharp Corp
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Filing: 1991-10-21
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Granted: 1993-04-20
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Expires: 2011-10-21
Abstract
Abstract An inspection method of liquid crystal panel by comparing characteristics of histogram of a part mounted on the panel with a reference histogram which is obtained from a part of the panel to be inspected.
Inventors
- 👤 Ryohei Kumagai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:34
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/1306; G02F1/1309; Y; Y10; Y10S; Y10S345/00; Y10S345/904
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
135 words
An inspection method of liquid crystal panel for judging if a part of said liquid crystal panel is defective or not comprising steps of: taking an image of said liquid crystal panel with lighting said panel; calculating histograms of parts mounted on said liquid crystal panel from said image; classifying said parts into groups according to characteristics value of said histogram; selecting one group with maximal number of members from said groups; selecting a reference histogram from histograms of said parts of said group selected; and comparing histograms of parts belonging to other groups than said groups selected with said reference histogram so that a defective part is extracted as defective part when a difference is greater than a predetermined value between said histogram of said parts of said other groups and said reference histogram.
Claim 2
Dependent Claim
135 words
An inspection method of liquid crystal panel for judging if a part of said liquid crystal panel is defective or not comprising steps of: taking an image of said liquid crystal panel with lighting said panel; calculating histograms of parts mounted on said liquid crystal panel from said image; classifying said parts into groups according to characteristics value of said histogram; selecting one group with maximal number of members from said groups; selecting a reference histogram from histograms of said parts of said group selected; and comparing histograms of parts belonging to other groups than said groups selected with said reference histogram so that a defective part is extracted as defective part when a difference is greater than a predetermined value between said histogram of said parts of said other groups and said reference histogram.
Claim 3
Dependent Claim
32 words
An inspection method of liquid crystal panel as claimed in claim 1, wherein said reference histogram is obtained by calculating a mean value of histograms of said parts of said group selected.
Claim 4
Dependent Claim
26 words
An inspection method of liquid crystal panel as claimed in claim 1, wherein said reference histogram is obtained by selecting one part in said group selected.
Claim 5
Dependent Claim
38 words
An inspection method of liquid crystal panel as claimed in claim 1, wherein said panel is lighted from front side of said panel whereby defects of break, big hole and pin point, roughness and light blot are detected.
Claim 6
Dependent Claim
30 words
An inspection method of liquid crystal panel as claimed in claim 1, wherein said panel is lighted from back side of said panel whereby defects of rising lead is detected.
Claim 7
Dependent Claim
26 words
An inspection method of liquid crystal panel as claimed in claim 1, wherein said characteristics value is number of pixels of each brightness of said histogram.
Claim 8
Dependent Claim
22 words
An inspection method of liquid crystal panel as claimed in claim 1, wherein said characteristics value is second moment of said histogram.
Claim 9
Dependent Claim
21 words
An inspection method of liquid crystal panel as claimed in claim 1, wherein said characteristics value is variance of said histogram.
Claim 10
Dependent Claim
35 words
An inspection method of liquid crystal panel as claimed in claim 6, wherein said characteristics value is compared by subtracting number of pixels of each brightness of said histograms to be compared with each other.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-04-19 | 1996-10-19 | 1997-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-19 | 2000-10-19 | 2001-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-19 | 2004-10-19 | 2005-04-20 | $7700.00 | Window Closed / Lapsed |