Structure and drive scheme for light emitting device matrix as display light source

• US 7,612,843 B2
• Filed: 05/25/2007
• Issued: 11/03/2009
• Est. Priority Date: 05/25/2006
• Status: Expired due to Fees

• Current Assignee: Chen-Jean Chou
• Original Assignee: Chen-Jean Chou
• Inventors: Chou, Chen-Jean
• Primary Examiner(s): QI, ZHI QIANG
• Application Number:
  US11/754,268
• Publication Number:
  US 20080170054A1
• Time in Patent Office: 893 Days
• Field of Search: 349/61, 345/205
• US Class Current: 349/61
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 3/325 the data current flowing through the driving transistor during a setting phase, e.g. by using a switch for connecting the driving transistor to the data driver
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A system and driving method are provided to accurately reproduce an input image using calibrated intensity profile. Extended dynamic range can be obtained according to the computation method. Improved structures for solid-state backlighting system suitable for such application are provided.

Claims

1. A display device for displaying image according to an image data, comprising an active matrix of light modulators and a plurality of lighting elements;

said display further comprising;

a data storage device storing a first reference information;

a control circuit controlling said modulators according to modulation data and controlling the output of said lighting elements according to lighting control data;

wherein said first reference information further comprising data corresponding to the intensity of light exiting said light modulators;

wherein said control circuit synthesizes said modulation data according to said first reference and said lighting data;

said synthesizing further comprising at least one of the operations;

1) multiplication of said reference data by the lighting data of a lighting element;

     2) superimposing or adding data resulting from said multiplications from at least two said lighting elements;

     3) dividing the input image data by resulting said superimposed data.

2. The display according to claim 1 wherein said synthesizing comprising all three operations performed in sequence.

3. The display according to claim 1 comprising a second storage device storing a second reference information comprising scaling factors corresponding to the output intensity of lighting elements at a pre-determined level of lighting control data.

4. The display according to claim 3 wherein the control circuit further synthesizes lighting control data for a lighting element according to the operations:

1) determining the area brightness level from the input image data for an area corresponding to said lighting element;

2) computing lighting control data for said lighting element by scaling said brightness level with corresponding scaling factor stored in said second reference information;

wherein said area brightness level is the maximum brightness in said area multiplied by a pre-determined percentage.

5. The display according to claim 4 further comprising a memory buffer device storing at least two sequential frames of input image data;

wherein said control circuit synthesizing said modulation data leads said synthesizing the lighting data by at least one frame of image data.

6. The display according to claim 3, wherein said second reference information comprising the relative intensity of light exiting said active matrix modulators while a light source is set to a pre-determined output level, and while all pixels of said active matrix are set to either the lowest or the highest output state.

7. The display according to claim 3 wherein said second storage devices is programmable multiple times.

8. The display according to claim 1 wherein said first reference information comprising a relative intensity of light exiting said active matrix of modulators when a light source is set to a pre-determined level and said active matrix modulators are set to either the lowest or the highest output state.

9. The display according to claim 1 wherein said storage device is programmable multiple times.

10. The display according to claim 1, said plurality of lighting elements comprising an active matrix of light emitting devices, wherein each element of said active matrix comprising at least a light emitting device, a drive transistor modulating the current to said light emitting device according to a voltage signal, and a storage element storing said voltage.

11. The display according to claim 1 further comprising:

a control circuit generating a timing signal synchronizing with delivering drive current;

an interface reading signals from a detachable light sensing device;

wherein said control circuit synchronizes delivering of drive current and reading signals from said sensor;

said control circuit determining location address in said storage device for storing signal read from said sensor according to said timing signal.

12. The display according claim 11 wherein said control circuit generates an image comprising a pattern providing a spatial reference to the location of at least one said lighting element, and wherein said control circuit reads said pattern via said sensor according to said timing signal to determine the location of said sensor.

13. The display according to claim 1 wherein said plurality of lighting elements form an active matrix of light emitting elements.

14. An image display device comprising a first 2-dimensional array of image elements and a control circuit performing sequential operations comprising:

1) setting a section of elements to off or a dimming state, and

     2) applying data to elements within said section according to image data information;

wherein the duration of the off-state in said operation

     1) is within 10 milliseconds.

15. The display device according to claim 14 wherein the duration of combined operations 1) and 2) is shorter than 20 milliseconds.

16. The display device according to claim 15 wherein operation 1) precedes operation 2).

17. The display according to claim 16, said reference data comprising information characteristic to the spatial distribution of the light intensity exiting the light valves corresponding to a said lighting element at a pre-determined lighting level.

18. The display device according to claim 14, said image elements being light emitting elements.

19. The display device according to claim 14, said image elements being light valves.

20. The display device according to claim 14 comprising a first 2-dimensional array of lighting elements and a second 2-dimensional array of light valves.

21. The display device according to claim 14 wherein each lighting element distributes light to a confined area of the light valves;

wherein at the far edge of any adjacent area, light intensity decreases to below 1/20 of the highest intensity inside said confined area;

wherein said confined area comprises fewer than 1/50 of the light valves.

22. The display according to claim 21 wherein said confined area comprises fewer than 1/200 of the total elements of the light valves.

23. The display according to claim 20 wherein said 2D array of lighting elements is an active matrix, wherein each element comprising a light emitting device, a switching device, and a storage device to retain lighting data.

24. The display according to claim 23 wherein said switching device and storage device are arranged remotely connecting to the light emitting device with conductor lines.

25. The display according to claim 20 wherein a said lighting element comprising a plurality of light emitting devices.

26. The display according to claim 20 wherein each said lighting elements comprising a plurality of light emitting diodes connected in series.

27. The display device according to claim 14, wherein said 2D array of light valves is arranged in parallel with array of lighting elements, further comprising a structure for light confinement, said structure comprising separators between adjacent confinement areas arranged perpendicular to the confined area of light valves and along the boundary of the confined areas.

28. The display according to claim 27 wherein said separator is opaque.

29. The display according to claim 27 wherein said separator comprising reflective surface reflecting light.

30. The display according to claim 27 wherein said separator comprising white surface reflecting broadband spectrum or multiple narrowband spectra.

31. The display according to claim 27 wherein said separator comprising surface reflecting at least one primary narrowband (color).

32. The display device according to claim 27 wherein said separator comprises diffusive reflecting surface.

33. The display device according to claim 14 wherein said a section of pixels comprises a plurality of subsets of pixels, each pixel comprising a light valve;

said operation

     2) comprising in further detail;

selecting, sequentially, each and every subset of pixels; and

applying data to pixels in said subset, when selected, according to data information.

34. The display according to claim 14 further comprising a structure confining the output light of a said pixel of light emitting device to an area of active matrix of light valves;

wherein said area comprising fewer than 1/50 of the total pixels of said matrix of light valves;

said structure comprising separator between adjacent lighting elements;

said separator comprising a surface reflecting light.

35. The display according to claim 34 further comprising a data storage device containing a reference data;

said reference data comprising information characteristic to the light intensity exiting the light valves corresponding to a said light emitting device at a pre-determined lighting level.

36. The display according to claim 14 wherein said light emitting device is one of:

light emitting diode, thin-film organic light emitting diode.

37. The display according to claim 14 wherein said second storage device comprises one of:

a capacitor storing voltage, a plurality of binary devices storing digital data.

38. The display according to claim 14, wherein said second control circuit is arranged in a collection remotely connected to a plurality of the light emitting devices.

39. An image display device comprising:

a plurality of light emitting elements;

a plurality of light valves modulating light output from said light emitting elements;

a control circuit performing cyclic operations comprising;

     1) setting a section of light emitting elements to off or a dimming state;

     2) applying lighting data to the light emitting elements within said section according to image data information;

     3) setting a section of light valves to off or a dimming state;

wherein operation

     1) precedes

     2).

40. The display according to claim 39 wherein the duration of said step 1) is shorter than 10 milliseconds.

41. The display according claim 39 wherein said operations further comprising:

4) applying data to light valves by sequentially selecting and setting the brightness levels to subsections of light valves within said section of light valves according to data information.

42. The display according to claim 41 comprising at least a section of lighting elements illuminating a section of light valves, wherein applying data to said section of light valves is preceded by setting said section of lighting elements to off or a dimming state.

43. The display according to claim 41 wherein said sections of lighting elements and subsection of light valves are in rows, and are arranged in parallel.

44. The display device according to claim 39 comprising at least a section of light emitting elements illuminating a section of light valves, wherein in reference to such said sections, operation 3) precedes or synchronizes with operation 2).

45. The display according to claim 44 wherein applying data to said section of light emitting element is performed within 5 ms after setting said section of light valves to off state.

46. The display according to claim 39 comprising at least a section of lighting elements illuminating a section of light valves, wherein applying data to said section of lighting elements is preceded by setting said section of light valves to off or equivalent dimming state.

47. The display according to claim 46 wherein said applying data to light valves comprising sequentially selecting and setting image data to rows of light valves.

48. The display according to claim 39 comprising at least a section of light valves illuminated by a section of lighting elements;

said operations further comprising;

     1) setting said section of lighting elements to off or dimming state;

     2) setting said section of light valves to off or a dimming state;

     3) applying data to said section of light valves;

wherein operations

     1) and

     2) precede

     3).

49. The display according to claim 39 comprising at least a section of lighting elements distributing light to a first section and a second section of light valves;

said control means further comprising operations;

     1) applying image data to said first section of light valves;

     2) setting said second section of light valves to off or a dimming state;

     3) applying lighting data to said section of lighting elements;

wherein operation

     2) precedes operation

     3).

50. A display device for displaying image data comprising:

a first active matrix comprising a plurality of first select electrodes;

a plurality of first data electrodes;

a plurality of pixels each comprising a light valve, a first switching device, and a first storage device;

further comprising;

a second active matrix comprising a plurality of select electrodes;

a plurality of second data electrodes;

a 2-dimensional array of pixels of lighting elements, each comprising a light emitting device and a second control circuit comprising a second switching device and a second storage device;

wherein said light valves modulates light from said light emitting devices according to a modulation data applied to said light valves by sequentially selecting subsets of light valves and writing said data to the storage devices of selected subset;

wherein each said light emitting device emit light according to a lighting data applied to the pixel of lighting element by sequentially selecting said pixel and writing data to the storage devices of selected pixel;

wherein said writing data to a pixel of light valve precedes said writing data to a pixel of lighting element that dispenses light to said a light valve.

51. A display comprising:

a plurality of light emitting devices emitting light according to a drive current;

a control circuit delivers said drive current to said light emitting device;

said display further comprises;

a data storage device storing reference information corresponding to the intensity of light output from said light emitting devices;

wherein said control circuit generates drive current scaling to said reference information;

said data storage device being re-programmable multiple times.