US5081687A
Expired / Lapsed
US
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Method and apparatus for testing LCD panel array prior to shorting bar removal
Assignee: Photon Dynamics Inc
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Filing: 1990-11-30
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Granted: 1992-01-14
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Expires: 2010-11-30
Abstract
Abstract Final testing of an LCD panel or the like is performed after preliminary testing for short circuit defects. During final testing, the panel is exposed to signals at the shorting bars and the resulting display pattern is imaged. The resulting image data then is processed at a computer system to determine whether the resulting display pattern differs from an expected display pattern. If differences are present then an open circuit or pixel defect is present. The applied test signals and the pattern or differences determine the type of defect present. For an open circuit defect along a gate line, a partial row (column) of the resulting display pattern does not activate. For an open circuit along a drive line, a partial column (row) of the resulting display does not activate. Pixel shorts are identified by applying test signals to the shorting bars during a first test cycle, then imaging the display during a second test cycle after at least one of the test signals is removed. Pixels which remain active that should be inactive have short circuit defects.
Inventors
- 👤 Francois J. Henley
- 👤 Stephen Barton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:35
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/006; G01; G01R; G01R31/00; G01R31/28; G01R31/316; G06; G06F; G06F11/00; G06F11/22; G06F11/24; Y; Y10; Y10S; Y10S345/00; Y10S345/904
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
136 words
A method for testing an LCD panel having a plurality of drive lines oriented in a first direction and a plurality of gate lines oriented in a second generally orthogonal direction creating row/column intersections, each drive line which terminates along a first edge of the panel being shorted together by a first shorting means, each gate line which terminates along a second edge of the panel being shorted together by a second shorting means, said method comprising the steps: applying a first test signal to said first shorting means and a second test signal to said second shorting means to generate a first resulting display pattern; comparing said first resulting display pattern to an expected display pattern, a difference between the resulting display pattern and the expected display pattern signifying that the panel has a defect.
Claim 2
Independent Claim
136 words
A method for testing an LCD panel having a plurality of drive lines oriented in a first direction and a plurality of gate lines oriented in a second generally orthogonal direction creating row/column intersections, each drive line which terminates along a first edge of the panel being shorted together by a first shorting means, each gate line which terminates along a second edge of the panel being shorted together by a second shorting means, said method comprising the steps: applying a first test signal to said first shorting means and a second test signal to said second shorting means to generate a first resulting display pattern; comparing said first resulting display pattern to an expected display pattern, a difference between the resulting display pattern and the expected display pattern signifying that the panel has a defect.
Claim 3
Dependent Claim
70 words
The method of claim 1, further comprising the step of imaging a portion of said first resulting display pattern to generate sensed image data; wherein said expected display pattern comprises expected image data; and wherein said step of comparing comprises processing said sensed image data by comparing said sensed image data to expected image data, a difference between sensed image data and expected image data resulting from a panel defect.
Claim 4
Independent Claim
194 words
A method for testing an LCD panel having a plurality of drive lines oriented in a first direction and a plurality of gate lines oriented in a second generally orthogonal direction creating row/column intersections, each drive line which terminates along a first edge of the panel being shorted together by a first shorting means, each drive line which terminates along a second opposing edge of the panel being shorted together by a second first shorting means, each gate line which terminates along a third edge of the panel being shorted together by a third shorting means, each gate line which terminates along a fourth edge of the panel being shorted together by a fourth shorting means, said method comprising the steps: applying a first test signal to said first shorting means, a second test signal to said second shorting means, a third test signal to said third shorting means and a fourth test signal to said fourth shorting means to generate a resulting display pattern; comparing said resulting display pattern to an expected display pattern, a difference between the resulting display pattern and the expected display pattern signifying that the panel has a defect.
Claim 5
Independent Claim
194 words
A method for testing an LCD panel having a plurality of drive lines oriented in a first direction and a plurality of gate lines oriented in a second generally orthogonal direction creating row/column intersections, each drive line which terminates along a first edge of the panel being shorted together by a first shorting means, each drive line which terminates along a second opposing edge of the panel being shorted together by a second first shorting means, each gate line which terminates along a third edge of the panel being shorted together by a third shorting means, each gate line which terminates along a fourth edge of the panel being shorted together by a fourth shorting means, said method comprising the steps: applying a first test signal to said first shorting means, a second test signal to said second shorting means, a third test signal to said third shorting means and a fourth test signal to said fourth shorting means to generate a resulting display pattern; comparing said resulting display pattern to an expected display pattern, a difference between the resulting display pattern and the expected display pattern signifying that the panel has a defect.
Claim 6
Dependent Claim
69 words
The method of claim 3, further comprising the step of imaging a portion of said resulting display pattern to generate sensed image data; wherein said expected display pattern comprises expected image data; and wherein said step of comparing comprises processing said sensed image data by comparing said sensed image data to expected image data, a difference between sensed image data and expected image data resulting from a panel defect.
Claim 7
Independent Claim
151 words
An apparatus for testing an LCD panel, the panel having a plurality of drive lines oriented in a first direction and a plurality of gate lines oriented in a second generally orthogonal direction creating row/column intersections, each drive line which terminates along a first edge of the panel being shorted together by a first shorting means, each gate line which terminates along a second edge of the panel being shorted together by a second shorting means, said apparatus comprising: means for applying a first test signal to said first shorting means and for applying a second test signal to said second shorting means to generate a resulting display pattern; means for imaging the resulting display pattern to generate sensed image data; means for comparing the sensed image data to expected image data, a difference between the sensed image data and the expected image data signifying that the panel has a defect.
Claim 8
Independent Claim
151 words
An apparatus for testing an LCD panel, the panel having a plurality of drive lines oriented in a first direction and a plurality of gate lines oriented in a second generally orthogonal direction creating row/column intersections, each drive line which terminates along a first edge of the panel being shorted together by a first shorting means, each gate line which terminates along a second edge of the panel being shorted together by a second shorting means, said apparatus comprising: means for applying a first test signal to said first shorting means and for applying a second test signal to said second shorting means to generate a resulting display pattern; means for imaging the resulting display pattern to generate sensed image data; means for comparing the sensed image data to expected image data, a difference between the sensed image data and the expected image data signifying that the panel has a defect.
Claim 9
Dependent Claim
76 words
The apparatus of claim 5, in which the panel is an interdigitated panel having another plurality of drive lines which are shorted together by a third shorting means and another plurality of gate lines which are shorted by a fourth shorting means; in which said applying means also is for applying a third test signal to the third shorting means and a fourth test signal to the fourth shorting means to generate said resulting display pattern.
Claim 10
Dependent Claim
48 words
The apparatus of claim 6, in which said first test signal and said third test signal are inactive, and said second test signal and said fourth test signal are active, and wherein a difference between sensed image data and expected image data signifies a pixel short circuit defect.
Claim 11
Dependent Claim
38 words
The apparatus of claim 6, in which said first, second, third and fourth test signals are active, and wherein a difference between sensed image data and expected image data signifies that the panel has an open circuit defect.
Claim 12
Dependent Claim
61 words
The apparatus of claim 6, in which said first, second, third and fourth test signals are active during a first test cycle, said first and third test signals being switched to inactive during a second test cycle, wherein a difference between sensed image data and expected image data during said second test cycle signifies that the panel has a short circuit.
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) | 1995-01-13 | 1995-07-15 | 1996-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-01-13 | 1999-07-15 | 2000-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-01-13 | 2003-07-15 | 2004-01-14 | $7700.00 | Window Closed / Lapsed |