§
Luxuse
Patent Intelligence
Sign In
← Back to Patent Explorer
US4864290A Expired / Lapsed US ⏱️ 0.0 years remaining

Display device

Assignee: EMI Group Ltd
•
Filing: 1987-09-18
•
Granted: 1989-09-05
•
Expires: 2007-09-18
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract The liquid crystal display unit 1, has a video signal receiver 2 and a store 3. Time-modulation grey-scale addressing of the ferroelectric liquid crystal pixels in a display panel 4 is provided to a store 10 which records the number of changes of state for each pixel during one picture-signal. Once the most-significant bit has been processed and is being displayed on the panel 4, the change-of-state store 10 has the net number of changes which the pixel has undergone in that picture. Controller 11 causes store 10 to output the value appropriate to that pixel and pass it to driver unit 9 to produce a compensating pulse (whether positive, negative or zero) necessary to ensure that there is no net electrical potential over the entire picture interval. The display produced by the compensating pulse is cleared immediately the first data of the next picture is input to the pixel. Assuming that the LSB of the data for a pixel already on display in panel 4, then in the next scan extractor 6 passes the next LSB to comparator 7 whose other input is connected to a pixel-state store 8. Accordingly, the new bit-value is compared with the existing state of the pixel, and comparator 7 passes on an instructing signal to pixel driver unit 9 only if the state of the pixel requires changing; in such an eventuality, the driver unit 9 issues an appropriate monopulse select voltage. Comparator 7 also passes such an instructing signal.

Inventors

  • 👤 Colin M. Waters

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-30 21:52
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/12; H04N3/127

Claims Analysis

Total Claims: 12
Claim 1
Independent Claim 135 words
A display device comprising: a lattice of pixels; means to receive a signal representing a picture for display, the signal comprising one or more portions for each pixel; means to address each pixel a number of times for each picture-signal, the addressing means including means to apply a uni-polar signal to the pixel in accordance with a respective said one or more portion; means to address each pixel a number of times for each picture-signal, the addressing means including means to apply a uni-polar signal to the pixel in accordance with a respective said one or more portion; means to determine any net electrical potential value resultant from the addressing of a pixel for one picture; and means to apply a correction signal to a pixel in accordance with the output from the determining means.
Claim 2
Dependent Claim 135 words
A display device comprising: a lattice of pixels; means to receive a signal representing a picture for display, the signal comprising one or more portions for each pixel; means to address each pixel a number of times for each picture-signal, the addressing means including means to apply a uni-polar signal to the pixel in accordance with a respective said one or more portion; means to address each pixel a number of times for each picture-signal, the addressing means including means to apply a uni-polar signal to the pixel in accordance with a respective said one or more portion; means to determine any net electrical potential value resultant from the addressing of a pixel for one picture; and means to apply a correction signal to a pixel in accordance with the output from the determining means.
Claim 3
Dependent Claim 56 words
A display device according to claim 1, wherein the addressing means comprises means to apply a uni-polar signal to a pixel only when there is a change in the state of the pixel, and the determining means comprises means to count the number of changes in state for a pixel during its addressing for one picture-signal.
Claim 4
Dependent Claim 38 words
A display device according to claim 1, wherein the correction means applied a correction signal to a pixel in respect of its addressing for one picture-signal prior to the initiation of the subsequent address for the next picture.
Claim 5
Dependent Claim 47 words
A display device according to claim 1, wherein the display device comprises means to store the output of the determining means as stored information for each of a number of pixels, and means to pass the stored information to the correction means to apply a correction signal.
Claim 6
Dependent Claim 16 words
A display device according to claim 1, wherein liquid crystal cells form the lattice of pixels.
Claim 7
Independent Claim 97 words
A method of operating a display device having a lattice of pixels, the method comprising the steps of: receiving a signal representing a picture for display, the signal comprising one or more portions for each signal; addressing each pixel a number of times for each picture-signal, including applying a uni-polar signal to the pixel in accordance with a respective said one or more portions; determining any net electrical potential value resultant from the addressing of a pixel for one picture; and applying a correction signal to a pixel in accordance with the result of the determining step.
Claim 8
Independent Claim 97 words
A method of operating a display device having a lattice of pixels, the method comprising the steps of: receiving a signal representing a picture for display, the signal comprising one or more portions for each signal; addressing each pixel a number of times for each picture-signal, including applying a uni-polar signal to the pixel in accordance with a respective said one or more portions; determining any net electrical potential value resultant from the addressing of a pixel for one picture; and applying a correction signal to a pixel in accordance with the result of the determining step.
Claim 9
Dependent Claim 43 words
A method according to claim 6, comprising applying a uni-polar signal to a pixel only when there is a change in the state of the pixel, and counting the number of changes in state for a pixel during its addressing for one picture-signal.
Claim 10
Dependent Claim 34 words
A method according to claim 6, comprising applying a correction signal to a pixel in respect of its addressing for one picture-signal prior to the initiation of the subsequent address for the next picture.
Claim 11
Dependent Claim 35 words
A method according to claim 6, comprising storing the result of the determining step as stored information for each of a number of pixels, and applying a correction signal, in response to the stored information.
Claim 12
Dependent Claim 15 words
A method according to claim 6 wherein liquid crystal cells form the lattice of pixels.

References Cited (Backward Citations)

GB1594151A Cited
GB2079509A Cited
US4525710A Cited
US4508429A Cited
EP0151508A2 Cited
US4709995A Cited
US4712877A Cited
US4705345A Cited
US4728947A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1992-09-04 1993-03-06 1993-09-05 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1996-09-04 1997-03-06 1997-09-05 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2000-09-04 2001-03-06 2001-09-05 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag