Display device with a light shutter front end unit and gas discharge back end unit

• US 5,461,397 A
• Filed: 10/07/1993
• Issued: 10/24/1995
• Est. Priority Date: 10/08/1992
• Status: Expired due to Fees

• Current Assignee: Panocorp Display Systems
• Original Assignee: Panocorp Display Systems
• Inventors: Chen, Hsi-Sheng, Zhang, Chao, Ge, Shichao, Feng, Yu, Liang, Jemm Y.
• Primary Examiner(s): BRIER, JEFFERY A
• Application Number:
  US08/133,561
• Time in Patent Office: 747 Days
• Field of Search: 345/4, 345/5, 345/62, 345/66, 345/102
• US Class Current: 345/102
• CPC Class Codes: G02F 1/133604 with lamps
• CPC Class Codes: G02F 1/133622 Colour sequential illumination
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A display device containing an LCD light shutter front end to modulate light transmittance and a substantially flat gas discharge back end unit containing multiple gas discharge tunnels. The back end unit contains priming means to allow fast ignition of gas discharge and control means to allow independent discharge control of each discharge tunnel. The control circuit is further simplified to allow a small number of driving signals to control a large number of discharge tunnels. This backlight structure allows color light pulses to be generated in synchronization with the scanning operation of the front end unit. The combined operation of these two units can produce color images through time sequential color mixing principle. Compact and power efficient color display panels can be produced without the use of color filter in the LCD.

Claims

1. A display apparatus comprising:

(a) a front end unit including;

a body having rows of areas that are light modulating defining arrays of pixels for light transmission;

a front end control device controlling intensity of light transmission through the pixels for displaying images; and

(b) a back end unit including;

a housing having at least one array of gas discharge channels substantially parallel to the arrays of pixels, wherein gas discharge in said channels causes said channel to emit light;

priming means populating at least some of the channels with charged particles before gas discharge occurs in said at least some of the channels;

a back end control device controlling gas discharge in said channels so that gas discharge occurs in each of said at least some channels after it is populated therein with charged particles, said back end control device controlling gas discharge in said channels so that selected channels of said at least some channels emit light sequentially to supply light to the front end unit for displaying images.

2. The apparatus of claim 1, said priming means including one or more passages in said housing in communication with said at least some of the channels so that charged particles resulting from gas discharge in one or more of said at least some channels facilitates subsequent gas discharges in one or more different ones of said at least some of the channels.

3. The apparatus of claim 2, wherein each of the channels have first and second ends, said one or more passages connecting the first ends of some of the channels to permit the propagation of charged particles between different channels through said passages.

4. The apparatus of claim 3, said back end unit further including discharge electrodes at or near the second ends.

5. The apparatus of claim 3, said priming means further including a pilot reset electrode in the one or more passages at or near the first end of a channel for initiating gas discharge for one or more scanning cycles.

6. The apparatus of claim 3, said back end control device causing gas discharge in a pair of two channels simultaneously and at least a portion of the one or more passages connecting the two channels, said device causing gas discharge sequentially in different pairs of channels in a plurality of consecutive time intervals, said back end control device being such that during at least two consecutive time intervals, the two pairs of channels in which gas discharge occurs during such intervals overlap by at least one channel, so that charged particles generated during the earlier of the two consecutive time intervals facilitate gas discharge during the later of the two consecutive time intervals.

7. The apparatus of claim 2, said housing comprising channel walls separating adjacent channels, said priming means including an array of passages each connecting two adjacent channels to permit the propagation of charged particles between adjacent channels.

8. The apparatus of claim 7, said array of passages aligned substantially along a line transverse to the array of channels to permit the propagation of charged particles sequentially through the aligned array of passages from one channel to the next in the array of channels to facilitate sequential gas discharge in the array of channels.

9. The apparatus of claim 8, said channels having ends, said array of passages located near the ends of the channels.

10. The apparatus of claim 8, said array of passages being aligned substantially along a zigzag line that is substantially perpendicular to the channels.

11. The apparatus of claim 8, said back end unit further comprising discharge electrodes in each channel for controlling gas discharge in the channels.

12. The apparatus of claim 11, said priming means further including one or more pilot discharge electrodes in each channel and located in the vicinity of the passage or passages connecting such channel to adjacent channel or channels for controlling pilot gas discharge in such channel to generate discharge particles that facilitate gas discharge in such channel as controlled by the discharge electrodes.

13. The apparatus of claim 12, wherein an electrode in at least one channel serves as a pilot discharge electrode as well as a discharge electrode, thereby reducing the number of electrodes in such at least one channel.

14. The apparatus of claim 12, wherein said back end control device and/or the priming means applies control signals to the pilot discharge electrodes in each channel to cause gas discharge therein, said signals applied to the pilot discharge electrodes in channel by channel sequentially in the array of channels to cause gas discharges across the pilot discharge electrodes in channel by channel sequentially in the array of channels.

15. The apparatus of claim 14, wherein said back end control device applies an electrical potential across the discharge electrodes of a selected channel to cause gas discharges across a main portion of the selected channel after gas discharge has started across the pilot discharge electrodes in such channel to provide charged particles for facilitating gas discharge in the main portion.

16. The apparatus of claim 14, wherein the array of pilot discharge electrodes are connected electrically into multiple groups, said back end control device and/or the priming means applying said control signals in multiple phase self scanning mode.

17. The apparatus of claim 1, said body being a layer of light modulating material, said front end control device including an array of row electrodes and an array of column electrodes transverse to the array of row electrodes, said row electrodes overlapping column electrodes over said layer when viewed in a viewing direction to define consecutive rows of pixels at the layer, so that light transmittance through the pixels is controlled by electrical signals applied to the row and column electrodes.

18. The apparatus of claim 17, said front end control device applying two or more sequences of electrical signals to the row and column electrodes to cause the light transmittance through the pixels to sequentially change one row at a time, defining a scanning process sequentially scanning the rows of pixels during which one row of pixels is scanned at a time, each sequence corresponding to one of a plurality of colors, wherein each sequence of electrical signals controls the light transmittance of the rows of pixels for passage of light of the corresponding color.

19. The apparatus of claim 18, said at least one array of gas discharge channels being substantially parallel to the row electrodes, each channel overlapping at least one corresponding row of pixels in the front end unit when viewed in the viewing direction, said channels emitting light of one of said plurality of colors when gas discharge occurs in said channels;

said back end control device controlling gas discharge in said channels so that each of said at least some channels emits light of one of said plurality of colors at a predetermined delay after the application of electrical signals in the sequence corresponding to such color to change the light transmittance of the at least one row of pixels corresponding to such channel for passage of light.

20. The apparatus of claim 1, wherein each of at least some of said channels includes a main portion and a pilot portion, and photo-luminescent material coating at the main portion, but no photo-luminescent material coating at the pilot portion, to reduce light emission from the pilot portions.

21. The apparatus of claim 1, wherein the back end unit further comprises cold cathodes in the channels for causing gas discharge in the channels.

22. The apparatus of claim 1, said back end unit further comprising reflectors at the channels to project light towards the front end unit.

23. The apparatus of claim 1, wherein the priming means includes a keep alive cell to continuously generate charged particles.

24. The apparatus of claim 1, the housing of said back end unit including an array of spacers, arranged with one or more spacers separating any two adjacent channels to isolate the gas discharges in any two adjacent channels from each other.

25. The apparatus of claim 24, said spacers comprising an array of tubes each defining a channel therein.

26. The apparatus of claim 24, said housing comprising a face plate and a back plate with ribs facing and attached to the front plate to define channels, wherein the ribs are the spacers.

27. The apparatus of claim 26, said housing further comprising one or more coating on the back plate to reflect both visible light and ultraviolet light.

28. The apparatus of claim 26, said housing further comprising a layer between the front and back plates, said layer reflecting ultraviolet light and transmitting visible light.

29. The apparatus of claim 26, said back end unit further including discharge electrodes on the face plate.

30. The apparatus of claim 1, said back end unit further including two or more discharge electrodes in each channel, each of said channels having two ends, wherein at least one of the discharge electrodes is located between the ends of a channel to divide such channel into shorter channels with a shorter gas discharge path.

31. The apparatus of claim 30, each of said channels having two ends, said back end unit further including four discharge electrodes in each channel, two discharge cathodes at or close to the ends of each channel, and two discharge anodes between the two ends of each channel.

32. A display method employing a device comprising a front end unit including a body having arrays of areas that are light modulating defining arrays of pixels for light transmission and a back end unit including a housing having at least one array of gas discharge channels substantially parallel to the arrays of pixels, wherein gas discharge in said channels causes said channel to emit light;

said method comprising;

modulating the intensity of light transmission through the pixels for displaying images; and

populating at least some of the channels with charged particles before gas discharge occurs in main portions of said at least some of the channels and causing gas discharge in main portions of said channels so that gas discharge occurs in main portion of each of said at least some channels after it is populated therein with charged particles, and so that selected channels of said at least some channels emit light sequentially to supply light to the front end unit for displaying images.

33. The method of claim 32, said body being a layer of light modulating material, said front end unit including an array of row electrodes and an array of column electrodes transverse to the array of row electrodes, said row electrodes overlapping column electrodes over said layer of light modulating material when viewed in a viewing direction to define consecutive rows of pixels at the layer;

wherein said modulating step applies two or more sequences of electrical signals to the row and column electrodes, each sequence causing the light transmittance through the pixels to sequentially change one row at a time, defining a scanning process sequentially scanning the rows of pixels during which one row of pixels is scanned at a time, each sequence corresponding to one of a plurality of colors, wherein each sequence of electrical signals controls the light transmittance of the rows of pixels for passage of light of the corresponding color.

34. The method of claim 33, wherein said at least one array of gas discharge channels is substantially parallel to the row electrodes, each channel overlapping at least one corresponding row of pixels in the front end unit when viewed in the viewing direction, said channels emitting light of one of said plurality of colors when gas discharge occurs in said channels;

wherein said populating and causing step causes each of said at least some channels to emit light of one of said plurality of colors at a predetermined delay after the application of electrical signals in the sequence corresponding to such color to change the light transmittance of the at least one row of pixels corresponding to such channel for passage of light.

35. The method of claim 32, said populating and causing step populating the at least some of the channels consecutively with charged particles by populating each of said some of the channels, followed by populating a channel adjacent to such channel before gas discharge occurs in main portions of such channels.

36. The method of claim 35, said populating and causing step including causing a pilot gas discharge in a pilot portion of each of said some of the channel so that the pilot gas discharges occur channel by channel consecutively in the at least some of the channels.

37. The method of claim 35, said populating and causing step causes gas discharges in main portions of selected channels, wherein the gas discharge occurring in the main portion of a selected channel occurs after a pilot gas discharge in such channel has populated such channel with charged particles but before such particles are dissipated.

38. The method of claim 32, said populating and causing step causes gas discharge sequentially in different pairs of channels in a plurality of consecutive time intervals, said populating and causing step being such that during at least two consecutive time intervals, the two pairs of channels in which gas discharge occurs during such intervals overlap by at least one channel, so that charged particles generated during the earlier of the two consecutive time intervals facilitate gas discharge during the later of the two consecutive time intervals.

39. A display device comprising:

a front end unit having an array of row electrodes and an array of column electrodes transverse to the array of row electrodes, said row electrodes overlapping column electrodes over a layer of light modulating material when viewed in a viewing direction to define consecutive rows of pixels at the layer, so that light transmittance through the pixels is controlled by electrical signals applied to the row and column electrodes;

a front end control unit applying two or more sequences of electrical signals to the row and column electrodes to cause the light transmittance through the pixels to sequentially change one row at a time, defining a scanning process sequentially scanning the rows of pixels during which one row of pixels is scanned at a time, each sequence corresponding to one of a plurality of colors, wherein each sequence of electrical signals controls the light transmittance of the rows of pixels for passage of light of the corresponding color; and

a back end unit having at least one array of gas discharge channels substantially parallel to the row electrodes, each channel overlapping at least one corresponding row of pixels in the front end unit when viewed in the viewing direction, said channels emitting light of one of said plurality of colors when gas discharge occurs in said channels;

priming means in the back end unit populating at least some of the channels with charged particles before gas discharge occurs in said at least some of the channels;

a back end control unit controlling gas discharge in said channels so that gas discharge occurs in each of said at least some channels after it is populated therein with charged particles, said back end control unit controlling gas discharge in said channels so that each of said at least some channels emits light of one of said plurality of colors at a predetermined delay after the application of electrical signals in the sequence corresponding to such color to change the light transmittance of the at least one row of pixels corresponding to such channel for passage of light.

40. A display method employing a device comprising:

a front end unit including an array of row electrodes and an array of column electrodes transverse to the array of row electrodes, said row electrodes overlapping column electrodes over a layer of light modulating material when viewed in a viewing direction to define consecutive rows of pixels at the layer, so that light transmittance through the pixels is controlled by electrical signals applied to the row and column electrodes;

a back end unit having at least one array of gas discharge channels substantially parallel to the row electrodes, each channel overlapping at least one corresponding row of pixels in the front end unit when viewed in the viewing direction, said channels emitting light of one of said plurality of colors when gas discharge occurs in said channels;

said method comprising;

applying two or more sequences of electrical signals to the row and column electrodes, each sequence causing the light transmittance through the pixels to sequentially change one row at a time, defining a scanning process sequentially scanning the rows of pixels during which one row of pixels is scanned at a time, each sequence corresponding to one of a plurality of colors, wherein each sequence of electrical signals controls the light transmittance of the rows of pixels for passage of light of the corresponding color;

populating each of at least some of the channels with charged particles;

causing gas discharge in said channels so that gas discharge occurs in each of said at least some channels after it is populated therein with charged particles, said gas discharge causing step also causes each of said at least some channels to emit light of one of said plurality of colors at a predetermined delay after the application of electrical signals in the sequence corresponding to such color to change the light transmittance of the at least one row of pixels corresponding to such channel for passage of light.