US5886474A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Luminescent device having drive-current controlled pixels and method therefor
Assignee: Joled Inc
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Filing: 1996-10-08
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Granted: 1999-03-23
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Expires: 2016-10-08
Abstract
Abstract A luminescent device (for example an autoluminescent flat display and particularly an organic electroluminescent device or display using an organic thin film as an electroluminescent layer) having a plurality of luminescing units (pixels PX) each selectively made to luminesce by a current is provided with a control part (current control circuit part 40) for accurately controlling the brightness of the luminescing units by controlling the current flowing through each luminescing unit on the basis of a brightness signal from outside, which is preferably supplied as pre-programmed memory information. As a result, it is possible to realize distinct luminescing (image display) at all times even with a passive matrix type pixel structure.
Inventors
- 👤 Nobutoshi Asai
- 👤 Yasunori Kijima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:12
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/22; G09G3/30; G09G3/32; G09G3/3208; G09G3/3216; G09G3/3266; G09G3/3275; G09G3/3283
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
179 words
A brightness controlled thin film luminescent display of the type having a first plurality and a second plurality of line-form electrodes that intersect one another to define a matrix and a light-emitting pixel connected between intersecting ones of the line-form electrodes of the first and second plurality of line-form electrode, each pixel emitting light of selected brightness as a function of a drive current flowing therethrough, the variation in brightness of a pixel from a selected brightness in response to a selected drive current varying as a function of the position of the pixel in the matrix, comprising: drive means for providing a selected drive signal to selected ones of the first plurality of line-form electrodes; a current-control device connected to each of the second plurality of line-form electrodes and controlled by a brightness control signal to control current flow through a connected pixel; a memory storing brightness control information for each pixel and providing a pixel-specific signal to the current control device of a selected pixel, the brightness control information remaining fixed through successive operations of a pixel.
Claim 2
Dependent Claim
179 words
A brightness controlled thin film luminescent display of the type having a first plurality and a second plurality of line-form electrodes that intersect one another to define a matrix and a light-emitting pixel connected between intersecting ones of the line-form electrodes of the first and second plurality of line-form electrode, each pixel emitting light of selected brightness as a function of a drive current flowing therethrough, the variation in brightness of a pixel from a selected brightness in response to a selected drive current varying as a function of the position of the pixel in the matrix, comprising: drive means for providing a selected drive signal to selected ones of the first plurality of line-form electrodes; a current-control device connected to each of the second plurality of line-form electrodes and controlled by a brightness control signal to control current flow through a connected pixel; a memory storing brightness control information for each pixel and providing a pixel-specific signal to the current control device of a selected pixel, the brightness control information remaining fixed through successive operations of a pixel.
Claim 3
Dependent Claim
87 words
The brightness controlled luminescent display of claim 1, wherein each current controlled device comprises: a fixed-value resistance in series circuit with said second line-form electrode providing a voltage drop thereacross corresponding to the current flow therethrough; a voltage-controlled resistance in series circuit with said fixed-value resistance; and a comparator for comparing the voltage drop across the fixed-value resistance with a voltage representative of the fixed value brightness information and providing a voltage output to the voltage-controlled resistance to effect current control in the connected second line-form electrode.
Claim 4
Dependent Claim
19 words
The brightness controlled luminescent display of claim 1, wherein said memory comprises a read-only-memory containing pre-stored brightness control information.
Claim 5
Dependent Claim
171 words
A brightness controlled thin film luminescent display of the type having a plurality of row electrodes and a plurality of column electrodes that intersect one another to define a matrix and a light-emitting pixel connected between intersecting ones of the row and column electrodes, each pixel emitting light of a selected brightness as a function of a drive current flowing therethrough, the variation in brightness of a pixel from a selected brightness in response to a selected drive current varying, in part, as a function of the position of the pixel in the matrix, comprising: drive means for providing a selected drive signal to selected ones of the row electrodes; a current-control device connected to each of the column electrodes and controlled by a brightness control signal to control current flow through a connected pixel; a pre-programmed memory storing brightness control information for each pixel and providing a pixel-specific signal to the current control device of a selected pixel, the brightness control information remaining fixed through successive operations of a pixel.
Claim 6
Dependent Claim
171 words
A brightness controlled thin film luminescent display of the type having a plurality of row electrodes and a plurality of column electrodes that intersect one another to define a matrix and a light-emitting pixel connected between intersecting ones of the row and column electrodes, each pixel emitting light of a selected brightness as a function of a drive current flowing therethrough, the variation in brightness of a pixel from a selected brightness in response to a selected drive current varying, in part, as a function of the position of the pixel in the matrix, comprising: drive means for providing a selected drive signal to selected ones of the row electrodes; a current-control device connected to each of the column electrodes and controlled by a brightness control signal to control current flow through a connected pixel; a pre-programmed memory storing brightness control information for each pixel and providing a pixel-specific signal to the current control device of a selected pixel, the brightness control information remaining fixed through successive operations of a pixel.
Claim 7
Dependent Claim
84 words
The brightness controlled luminescent display of claim 4, wherein each current control device comprises: a fixed-value resistance in series circuit with said column electrode providing a voltage drop thereacross corresponding to the current flow therethrough; a voltage-controlled resistance in series circuit with said fixed-value resistance; and a comparator for comparing the voltage drop across the fixed-value resistance with a voltage representative of the fixed-value brightness information and providing a voltage output to the voltage-controlled resistance to effect current control in the connected column electrode.
Claim 8
Dependent Claim
21 words
The brightness controlled luminescent display of claim 5, wherein said memory comprises a read-only-memory containing fixed value pre-stored brightness control information.
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) | 2002-03-22 | 2002-09-21 | 2003-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-03-22 | 2006-09-21 | 2007-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-03-22 | 2010-09-21 | 2011-03-23 | $7700.00 | Window Closed / Lapsed |