Methods and apparatus for ultra-violet stimulated displays

• US 7,088,335 B2
• Filed: 05/23/2003
• Issued: 08/08/2006
• Est. Priority Date: 04/28/1999
• Status: Expired due to Fees

• Current Assignee: DHP Media AB
• Original Assignee: Novus Partners LLC
• Inventors: McNeil, Laurie, Hunter, Charles Eric
• Primary Examiner(s): LAO, LUN YI
• Application Number:
  US10/444,079
• Publication Number:
  US 20040100437A1
• Time in Patent Office: 1,173 Days
• Field of Search: 345 87-102, 345/204, 349 61- 71
• US Class Current: 345/102
• CPC Class Codes: G02F 1/133617 Illumination with ultraviolet light; Luminescent elements or materials associated to the cell
• CPC Class Codes: G06Q 30/02 Marketing; Price estimation or determination; Fundraising
• CPC Class Codes: G09F 9/33 being semiconductor devices, e.g. diodes
• CPC Class Codes: G09F 9/35 being liquid crystals G09F9/302 takes precedence; liquid crystal materials C09K19/00; liquid crystal panels comprising a number of electrodes in a single cell per se G02F1/13
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2330/08 Fault-tolerant or redundant circuits, or circuits in which repair of defects is prepared
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 2380/06 Remotely controlled electronic signs other than labels
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G11B 33/10 Indicating arrangements; Warning arrangements G11B15/04, G11B19/04, G11B27/34, G11B27/36 take precedence
• CPC Class Codes: H04N 21/2543 Billing , e.g. for subscription services payment schemes, architectures or protocols G06Q20/00; e-commerce G06Q30/00; arrangements for billing for the use of broadcast information or broadcast-related information H04H60/21
• CPC Class Codes: H04N 21/26258 for generating a list of items to be played back in a given order, e.g. playlist, or scheduling item distribution according to such list retrieval of multimedia data based on playlists G06F16/40
• CPC Class Codes: H04N 21/41415 involving a public display, viewable by several users in a public space outside their home, e.g. movie theatre, information kiosk
• CPC Class Codes: H04N 21/47202 for requesting content on demand, e.g. video on demand
• CPC Class Codes: H04N 21/812 involving advertisement data advertising per se G06Q30/02
• CPC Class Codes: H04N 21/8153 : comprising still images, e.g. texture, background image
• CPC Class Codes: H04N 7/165 : Centralised control of user terminal subsequent to an upstream request signal H04N7/17345; Registering at central by two-way working H04N7/17309
• CPC Class Codes: H04N 7/17318 : Direct or substantially direct transmission and handling of requests

Abstract

A display element for use in a display device that exhibits extended illumination longevity and uniformity, as well as a wide viewing angle, is provided. The element can include a light source that emits ultraviolet light, a liquid crystal device having a plurality of independently controllable (i.e., addressable) shutters, a screening element between the light source and the liquid crystal device, a plurality of luminescent elements optically aligned with the shutters, and a regulated power supply. Display devices, calibration techniques, and power management methods are also provided.

Claims

1. A display element for use in a display device, wherein the element comprises:

a first light source that emits ultraviolet light;

a liquid crystal device having a plurality of independently controllable shutters;

a plurality of luminescent elements optically aligned with the plurality of shutters, wherein at least one of the luminescent elements absorbs at least some of the ultraviolet light and converts it to visible light, wherein the luminescent elements are disposed on the liquid crystal device, wherein the luminescent elements luminesce at different colors, wherein at least one of the luminescent elements comprises a material selected from a group consisting of a semiconductor, a phosphor, a gas, a plasma, an organic pigment, an inorganic pigment, and any combination thereof; and

a regulation circuit for regulating a power supply that supplies power to the light source, wherein the circuit is coupled to the power supply and the first light source, and wherein the regulation circuit comprises;

a photodetector that detects a portion of the ultraviolet light emitted from the light source and generates a first signal that is indicative of an intensity of the portion of light, wherein the photodetector is positioned such that the portion of the light is a reflected portion of the ultraviolet light,

a comparator circuit having an input for receiving the first signal, wherein the comparator circuit compares the first signal with a baseline signal and generates a second signal that is proportional to the difference between the first signal and the baseline signal, and

a controller circuit having an input for receiving the second signal and an output for supplying a regulated power signal to the light source.

2. The display element of claim 1 wherein the first light source is a light emitting diode.

3. The display element of claim 2 wherein the first light source is a surface-mounted light source.

4. The display element of claim 2 further comprising a second light source, and wherein the light sources emit a substantially equal intensity of the visible light on at least one of the luminescent elements.

5. The display element of claim 2 further comprising a second light source that emits ultraviolet light.

6. The display element of claim 5 wherein the second light source is active only when the first light source is inactive.

7. The display element of claim 6 wherein the second light source is adjacent the first light source such that the first and second light sources emit the light over a similar spatial profile.

8. The display element of claim 1 wherein the plurality of shutters have a variable transmissivity at energies that correspond to the ultraviolet light.

9. The display element of claim 1 wherein the plurality of shutters comprises at least three shutters and wherein the plurality of luminescent elements comprises at least three luminescent elements that luminesce at different colors when the light is incident on the elements.

10. The display element of claim 1 wherein the plurality of shutters comprises at least two sets of the shutters, and wherein each of the sets of the shutters comprises at least three shutters, and wherein each of the plurality of luminescent elements comprises at least two sets of the luminescent elements, and wherein each of the sets of the luminescent elements comprises at least three luminescent elements that luminesce at different colors when the light is incident on the elements.

11. The display element of claim 1 further comprising a screening element between the light source and the liquid crystal device that diffuses and collimates the light before being incident on the liquid crystal device.

12. The display element of claim 1 wherein the shutter has a light source side and a viewing side, and wherein the luminescent elements are located on the viewing side.

13. The display element of claim 1 wherein the plurality of luminescent elements comprises an element that luminesces substantially white light.

14. The display element of claim 1 wherein the reflected portion is reflected at least in part by a screening element located between the first light source and the plurality of luminescent elements.

15. The display element of claim 1 wherein the controller circuit is selected from a group consisting of a voltage controller and a current controller.

16. The display element of claim 1 further comprising a shutter controller that opens and closes each of the shutters, and wherein the controller circuit has an auto-zeroing feature that minimizes dark current when a shutter is closed.

17. The display element of claim 1 wherein the photodetector comprises at least one digital camera.

18. The display element of claim 1 further comprising a cooling plenum in thermal communication with the light source, wherein the plenum comprises a cooling material selected from a group consisting of gas and liquid.

19. The display element of claim 1 further comprising an optical protective filter on a viewer side of the luminescent elements that filters at least a portion of the ultraviolet light.

20. The display element of claim 19 wherein the filter is selected from a group consisting of a coating disposed on the liquid crystal device and a discrete filtering element.

21. The display element of claim 1 further comprising an optical stabilizing filter on a viewer side of at least one of the plurality of luminescent elements, wherein the stabilizing filter transmits a portion of the visible light, and wherein the portion includes a peak visible wavelength of the at least one of the plurality of luminescent elements.

22. A display device comprising:

a plurality of light sources that emits ultraviolet light;

a plurality of independently controllable shutters;

a plurality of luminescent elements optically aligned with each of the shutters,

wherein at least one of the luminescent elements absorbs at least some of the ultraviolet light and converts it to visible light; and

a regulated power supply for supplying power to the light source, wherein the regulated power supply comprises;

a power source, and

a regulation circuit coupled to the power source and the plurality of light sources, wherein the regulation circuit comprises;

a plurality of photodetectors that detects portions of light emitted from at least one of the plurality of light sources or and generates first signals that are indicative of intensities of the portions of light, wherein the plurality of photodetectors is positioned such that the portions of the ultraviolet light are portions reflected, at least in part, by a screen located between the light source and the liquid crystal device,

a comparator circuit having at least one input for receiving the first signals, wherein the comparator circuit compares the first signals with at least one baseline signal and generates second signals that are proportional to the difference between the first signals and the at least one baseline signal, and

a controller circuit having at least one input for receiving the second signals and at least one output for supplying regulated power signals to the plurality of light sources.

23. The display device of claim 22 wherein the plurality of light sources comprises a plurality of light emitting diodes.

24. The display device of claim 23 wherein the plurality of light sources are surface-mounted to a substantially planar structure.

25. The display device of claim 23 wherein the plurality of light sources comprises at least a first light source and a second light source, wherein the first light source is adjacent the second light source such that both sources emit light over a similar spatial profile, and wherein the power supply only supplies power to one of the first and second light sources at a time.

26. The display device of claim 22 wherein the plurality of light sources is in a substantially two-dimensional array, and wherein the power supply supplies an amount of electrical power to each of the plurality of light sources such that each of the plurality of shutters has substantially the same amount of ultraviolet light incident on it.

27. The display device of claim 26 wherein the plurality of light sources comprises:

a first light source; and

a second light source, and wherein the power supply adjusts the amount of electrical power to at least the second light source when the first light source fails.

28. The display device of claim 26 wherein the power supply includes a power management circuit that distributes power to each of the plurality of light sources such that each of the plurality of luminescent elements emits substantially the same amount of visible light when illuminated with the ultraviolet light.

29. The display device of claim 22 wherein each of the plurality of shutters comprises a liquid crystal and has a variable field-dependent transmissivity at energies that correspond to the ultraviolet light.

30. The display device of claim 22 wherein the plurality of shutters comprises at least three shutters and where each of the plurality of luminescent elements comprises at least three luminescent elements that luminesce at different colors when the light is incident on the elements.

31. The display device of claim 22 wherein the plurality of shutters comprises at least two sets of the shutters, and wherein each of the sets of the shutters comprises at least three of the shutters, and wherein each of the plurality of luminescent elements comprises at least two sets of the luminescent elements, and wherein each of the sets of the luminescent elements comprises at least three luminescent elements that correspond to the at least three shutters, and wherein the luminescent elements luminesce at different colors when the ultraviolet light is incident thereon.

32. The display device of claim 22 further comprising a screen between the light source and the liquid crystal device, wherein the screen diffuses and collimates the ultraviolet light emitted from the sources and directs the ultraviolet light toward at least one of the shutters.

33. The display device of claim 22 wherein each of the shutters has a light source side and a viewing side, and wherein each of the luminescent elements are located on the viewing side.

34. The display device of claim 22 wherein each of the luminescent elements are disposed on one of the shutters.

35. The display device of claim 34 wherein each of the at least two of the luminescent elements luminesce at a different color.

36. The display device of claim 35 wherein the plurality of luminescent elements comprises an element that luminesces substantially white light.

37. The display device of claim 35 wherein at least one of the luminescent elements-comprises a material selected from a group consisting of a semiconductor, a phosphor, a gas, a plasma, an organic pigment, an inorganic pigment, and any combination thereof.

38. The display device of claim 22 wherein the controller circuit is selected from a group consisting of a voltage controller and a current controller.

39. The display device of claim 22 further comprising a cooling plenum in thermal communication with the plurality of light sources.

40. The display device of claim 22 further comprising an optical protective filter on a viewer side of the plurality of the luminescent elements that filters at least a portion of the ultraviolet light emitted by the plurality of the light sources.

41. The display device of claim 40 wherein the protective filter is a coating disposed on a viewer'"'"'s side of the luminescent elements.

42. The display device of claim 22 further comprising an optical stabilizing filter on a viewer side of at least one of the plurality of luminescent elements, wherein the stabilizing filter transmits a portion of the visible light, wherein each of the portions includes a peak visible wavelength of the at least one of the plurality of luminescent elements.

43. The display device of claim 42 wherein the stabilizing filter is selected from group consisting of a coating disposed on the at least one of the plurality of luminescent elements and an element that is discrete from the liquid crystal device.

44. A display element for use in a display device, wherein the element comprises:

a first light source that emits ultraviolet light;

a liquid crystal device having a plurality of independently controllable shutters;

a plurality of luminescent elements optically aligned with the plurality of shutters, wherein at least one of the luminescent elements absorbs at least some of the ultraviolet light and converts it to visible light, wherein the luminescent elements are disposed on the liquid crystal device, wherein the luminescent elements luminesce at different colors, wherein at least one of the luminescent elements comprises a material selected from a group consisting of a semiconductor, a phosphor, a gas, a plasma, an organic pigment, an inorganic pigment. And any combination thereof and

a regulation circuit for regulating a power supply that supplies power to the light source, wherein the circuit is coupled to the power supply and the first light source, and wherein the regulation circuit comprises;

a photodetector that detects a portion of the ultraviolet light emitted from the light source and generates a first signal that is indicative of an intensity of the portion of light, wherein the photodetector is positioned such that the portion of the light is a reflected portion of the ultraviolet light, wherein the reflected portion is reflected at least in part by a screening element located between the first light source and the plurality of luminescent elements,

a comparator circuit having an input for receiving the first signal, wherein the comparator circuit compares the first signal with a baseline signal and generates a second signal that is proportional to the difference between the first signal and the baseline signal, and

a controller circuit having an input for receiving the second signal and an output for supplying a regulated power signal to the light source.