Display device

• US 5,093,652 A
• Filed: 02/26/1991
• Issued: 03/03/1992
• Est. Priority Date: 12/04/1987
• Status: Expired due to Term

• Current Assignee: Central Research Fund Limited
• Original Assignee: Thorn EMI Plc (Universal Music Group NV)
• Inventors: Bull, Stephen D., Morris, Christopher J.
• Primary Examiner(s): Brier, Jeffery A.
• Application Number:
  US07/660,265
• Time in Patent Office: 371 Days
• Field of Search: 340/701, 340/702, 340/703, 340/765, 340/784, 340/793, 350/339 F, 350/350 S
• US Class Current: 345/592
• CPC Class Codes: G09G 2310/0218 with collection of electrodes in groups for n-dimensional addressing
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

A display device has a lattice of pixel elements each selectably settable. A method of operating the display device comprises the steps of receiving a signal representing a picture for display during a display period and illuminating the lattice to produce, during a first interval within the display period, a first light output from the lattice having a first predetermined color characteristic and to produce at least one additional light output from the lattice. Each said additional light output has a different predetermined color characteristic and a respective interval within the display period separate from the first interval. The method further comprises the step of time-multiplex addressing blocks of pixel elements a plurality of address times during each interval. The addressing step includes setting a group of blocks, the group consisting of a plurality of blocks spaced apart in the addressing sequence such that the blocks in the group form a series with adjacent blocks having a temporal separation in the addressing sequence exhibiting a geometric progression with a common ratio N being an integer equal to 2 or more. In this way, addressing of the lattice occurs simultaneously with its illumination by the appropriate color, allowing a greater proportion of the frame time for the addressing operation so that additional addressing information can be utilized.

Claims

1. A method of operating a display device having a lattice of pixel elements such selectably settable, the method comprising:

receiving data representing a picture for display during a display period, which data comprises data-bits weighted in accordance with their significance;

illuminating the lattice to produce, during a first interval within the display period, a first light output from the lattice having a first predetermined colour characteristic and to produce at least one additional light output from the lattice, each said additional light output having a different predetermined colour characteristic and having a respective interval within the display period separate from the first interval; and

time-multiplex addressing, with the data, blocks of pixel elements a plurality of address times during each interval;

the blocks of pixel elements for time-multiplex addressing being selected such that they are spatially separated in accordance with a binary sequence, and selected blocks are selectively set for display in accordance with the significance of the weighted data-bits.

2. A method according to claim 1 wherein said step of illuminating the lattice includes a first step of illuminating the lattice during said first interval with a light source of said first predetermined colour characteristic and a second step of illuminating the lattice during said a respective interval with a light source of said a different predetermined colour characteristic.

3. A method according to claim 1 further comprising the step of blanking the lattice prior to each interval.

4. A method according to claim 1 wherein the step of blanking the lattice prior to each interval has a longer duration than a switching period between said first and second steps of illuminating the lattice.

5. A method according to claim 1 wherein the number of address times for said first interval is greater than the number of address times during said a respective interval whereby the resolution of said first predetermined colour is greater than the resolution of said different predetermined colour.

6. A method according to claim 1 wherein said first predetermined colour is green and the different predetermined colours are red and blue.

7. A display device comprising:

a lattice of pixel elements, each selectively settable in dependence upon a respective part of received data representing one picture for display in a display period, which data comprises data-bits weighted in accordance with their significance;

means for illuminating the lattice to produce, during a first interval within the display period, a first light output from the lattice having a first predetermined colour characteristic and to produce at least one additional light output from the lattice, each said additional light output having a different predetermined colour characteristic and having a respective interval within the display period and separate from the first interval;

and means for effecting time-multiplex addressing, with the data, blocks of pixel elements a plurality of address times for each interval of the illumination means;

the time-multiplex addressing means including means for selecting the blocks of pixel elements for time multiplex addressing such that the blocks of pixel elements are spatially separated in accordance with a binary sequence, and such that selected blocks are selectively set for display in accordance with the significance of the weighted data-bits.

8. A display device according to claim 7 wherein the illumination means comprises a light source of said first predetermined colour characteristic and a light source of each said different predetermined colour characteristic.

9. A display device according to claim 7 further comprising means for blanking the lattice prior to each interval.