Reflective and transflective operation modes for a display device

• US 9,398,666 B2
• Filed: 03/11/2011
• Issued: 07/19/2016
• Est. Priority Date: 03/11/2010
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Gandhi, Jignesh, Hagood, Nesbitt W. IV, Halfman, Mark Douglas, Kim, Je Hong
• Primary Examiner(s): Chow, Van
• Application Number:
  US13/583,586
• Publication Number:
  US 20130082607A1
• Time in Patent Office: 1,957 Days
• US Class Current: 1/1
• CPC Class Codes: G09G 2300/0456 with a reflective area and a transmissive area combined in one pixel, such as in transflectance pixels
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 2370/04 Exchange of auxiliary data, i.e. other than image data, between monitor and graphics controller
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3433 using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices using liquid crystal devices G09G3/36; using electrochromic devices G09G3/38
• CPC Class Codes: H05B 47/165 following a pre-assigned programmed sequence; Logic control [LC]
• CPC Class Codes: H05B 47/17 Operational modes, e.g. switching from manual to automatic mode or prohibiting specific operations

Abstract

A direct-view display apparatus includes a transparent substrate, an internal light source, a plurality of light modulators coupled to the transparent substrate, and a controller for controlling the states of the plurality of light modulators and the internal light source. The controller is configured to cause the display to transition from one of a transmissive, reflective and transflective mode, to a second of said modes.

Claims

1. A direct-view display apparatus, comprising:

a transparent substrate;

a metal layer over the transparent substrate having a plurality of apertures therein;

an internal light source;

a plurality of light modulators over the transparent substrate, each light modulator of the plurality of light modulators over at least one respective aperture of the plurality of apertures, each of the plurality of light modulators including at least one transflective element within a region defined by the at least one respective aperture, each transflective element capable of reflecting ambient light; and

a controller for controlling the states of the plurality of light modulators and the internal light source, the controller being configured to;

cause the display apparatus to display at least one image in a transmissive mode of operation by causing the internal light source to emit light at a first intensity and by outputting data signals indicative of desired states of the plurality of light modulators through a first set of data voltage interconnects coupled to the plurality of light modulators such that the plurality of light modulators modulate the light emitted by the internal light source at the first intensity;

detect a first signal configured to cause a transition from the transmissive mode of operation;

transition, in response to the first signal, to a transflective mode of operation, the transition to the transflective mode including decreasing the intensity of the internal light source from the first intensity to a second intensity; and

cause the display apparatus to display at least one image in the transflective mode of operation by outputting data signals indicative of desired states of the plurality of light modulators through the same first set of data voltage interconnects to the plurality of light modulators to modulate light originating from an ambient light source and the light originating from the internal light source at the second intensity.

2. The apparatus of claim 1, wherein the controller is further configured to:

detect a second signal configured to cause a transition from the transmissive or the transflective mode of operation;

transition, in response to the second signal, to a reflective mode of operation, the transition to the reflective mode including causing the internal light source to stop emitting light; and

cause the display apparatus to display at least one image in the reflective mode of operation by outputting data signals indicative of desired states of the plurality of light modulators through the same first set of data voltage interconnects to the plurality of light modulators to modulate light originating from the ambient light source.

3. The apparatus of claim 2, wherein the controller controls at least one light modulator of the plurality of light modulators capable of operating in both the transmissive mode and the reflective mode.

4. The apparatus of claim 2, wherein the second signal is based at least in part on detected ambient light.

5. The apparatus of claim 2, wherein displaying at least one image in the transmissive mode includes modulating light in accordance with a first number of grayscale divisions for the image, and wherein displaying at least one image in the transflective or reflective modes includes modulating light in accordance with a second number of grayscale divisions, wherein the second number of grayscale divisions is less than the first number of grayscale divisions.

6. The apparatus of claim 2, wherein displaying at least one image in the reflective mode includes at least one of modulating the image as a black and white image, and modulating light with at least 3 grayscale divisions.

7. The apparatus of claim 2, wherein displaying at least one image in the transmissive mode includes modulating the light according to a first frame rate.

8. The apparatus of claim 7, wherein displaying at least one image in the transflective or reflective modes includes modulating light in accordance with a second frame rate, wherein the second frame rate that is less than the first frame rate.

9. The apparatus of claim 2, wherein transitioning to the reflective mode of operation includes loading, from a memory, operating parameters corresponding to the reflective mode.

10. The apparatus of claim 2, wherein displaying at least one image in the reflective mode includes converting a color image into a black and white image for display.

11. The apparatus of claim 2, wherein displaying at least one image in the transmissive mode includes modulating the plurality of light modulators according to a first sequence of timing signals which control the loading of image data to the plurality of light modulators.

12. The apparatus of claim 11, wherein displaying at least one image in the transflective or reflective modes includes modulating the plurality of light modulators according to the same first sequence of timing signals which control the loading of image data to the plurality of light modulators.

13. The apparatus of claim 11, wherein displaying at least one image in the transflective or reflective modes includes modulating the plurality of light modulators according to a second sequence of timing signals that is different from the first sequence.

14. The apparatus of claim 13, wherein displaying at least one image in the transflective or reflective modes includes loading a subset of image data to the plurality of light modulators.

15. The apparatus of claim 1, wherein while in the transmissive mode, the plurality of light modulators are configured to modulate light emitted by the internal light source and light originating from the ambient light source.

16. The apparatus of claim 1, wherein the display apparatus consumes less power while operating in the transflective mode than while operating in the transmissive mode.

17. The apparatus of claim 1, wherein the controller is further capable of transitioning to an operating mode associated with a display of at least one image with more colors than another operating mode.

18. The apparatus of claim 1, wherein the controller derives the first signal from at least one of information to be displayed by the display apparatus and an amount of energy stored in a battery.

19. The apparatus of claim 1, wherein decreasing the first intensity of the light source during the transition to the transflective mode of operation includes decreasing the first intensity such that at least about 30% of the light modulated by the plurality of light modulators originates from the ambient light source.

20. The apparatus of claim 1, wherein the first signal is based at least in part on detected ambient light.

21. The apparatus of claim 20, wherein the internal light source includes at least first and second light sources corresponding to different colors, and wherein the controller measures at least one color component of the detected ambient light, and adjusts the first intensity of at least one of the first and second light sources based on the measurement of the at least one color component of the detected ambient light.

22. The apparatus of claim 1, wherein displaying at least one image in the transflective mode includes at least one of modulating the image as a black and white image, and modulating light with at least 3 grayscale divisions.

23. The apparatus of claim 1, wherein displaying at least one image in the transflective mode includes modulating light to form a color image, and wherein the image is modulated with only 1 grayscale division per color.

24. The apparatus of claim 1, wherein displaying at least one image in the transflective mode includes modulating light to form a color image, and wherein the image is modulated with at least 2 grayscale divisions per color.

25. The apparatus of claim 1, wherein the light emitted by the internal light source passes through a plane defined by the plurality of light modulators.

26. A direct-view display apparatus, comprising:

a transparent substrate;

an internal light source;

a plurality of light modulators coupled to the transparent substrate, each of the plurality of light modulators including at least one microelectromechanical systems (MEMS)-based shutter;

a controller for controlling the states of the plurality of light modulators and the internal light source, the controller being configured to;

cause the display apparatus to display at least one image in a transmissive mode of operation by causing the internal light source to emit light at a first intensity and by outputting data signals indicative of desired states of the plurality of light modulators through a first set of data voltage interconnects coupled to the plurality of light modulators such that the plurality of light modulators modulate the light emitted by the internal light source at the first intensity;

detect a first signal configured to cause a transition from the transmissive mode of operation;

transition, in response to the first signal, to a transflective mode of operation, the transition to the transflective mode including decreasing the intensity of the internal light source from the first intensity to a second intensity;

cause the display apparatus to display at least one image in the transflective mode of operation by outputting data signals indicative of desired states of the plurality of light modulators through the same first set of data voltage interconnects to the plurality of light modulators to modulate light originating from an ambient light source and the light originating from the internal light source at the second intensity.

27. apparatus of claim 26, each of the plurality of light modulators further including:

a metal layer having at least one aperture defined therein; and

at least one electrode;

the at least one MEMS-based shutter being translatable over the at least one aperture between at least an open position in which the shutter allows light to pass through the at least one aperture and a closed position in which the shutter blocks light from passing through the at least one aperture, the position of the at least one MEMS-based shutter being based on an electrical potential between the MEMS-based shutter and the at least one electrode.

28. The apparatus of claim 27, the metal layer having a front-facing surface and a rear-facing reflective surface, the apparatus further including:

a second reflective layer having a front-facing reflective surface; and

an optical cavity in the transparent substrate between the metal layer and the second reflective layer, the front-facing reflective surface of the second reflective layer and the rear-facing reflective surface of the metal layer capable of recycling light within the optical cavity.

29. The apparatus of claim 28, the internal light source being configured to emit the light into the optical cavity.

30. The apparatus of claim 29, each of the plurality of light modulators further including:

one or more transflective elements within a region defined by the at least one aperture.

31. The apparatus of claim 30, wherein, while in the transflective mode of operation:

the at least one MEMS-based shutter is configured to enable at least a portion of the ambient light to enter the optical cavity through the at least one aperture in regions between the one or more transflective elements or in regions between the one or more transflective elements and the metal layer; and

the optical cavity is configured to recycle the ambient light and to emit the recycled ambient light through the at least one aperture.

32. The apparatus of claim 30, wherein, while in the transflective mode of operation:

the at least one MEMS-based shutter is configured to enable at least a portion of the ambient light to reflect off of the one or more transflective elements.

33. A method for controlling a display apparatus, comprising:

displaying, by the display apparatus, at least one image in a transmissive mode of operation by causing an internal light source to emit light at a first intensity and by outputting data signals indicative of desired states of a plurality of light modulators such that the plurality of light modulators modulate the light emitted by the internal light source at the first intensity;

detecting a first signal configured to cause a transition from the transmissive mode of operation;

transitioning, in response to the first signal, to a transflective mode of operation, the transitioning including decreasing the intensity of the internal light source from the first intensity to a second intensity; and

displaying, by the display apparatus, at least one image in the transflective mode of operation by outputting data signals indicative of desired states of the plurality of light modulators such that the plurality of light modulators modulate light originating from an ambient light source and the light originating from the internal light source at the second intensity;

the display apparatus including a transparent substrate and a metal layer over the transparent substrate having a plurality of apertures therein;

each light modulator of the plurality of light modulators over at least one respective aperture of the plurality of apertures, each of the plurality of light modulators including at least one transflective element within a region defined by the at least one respective aperture, each transflective element capable of reflecting a portion of the ambient light.

34. The method of claim 33, further comprising:

detecting a second signal configured to cause a transition from the transmissive or the transflective mode of operation;

transitioning by the display apparatus, in response to the second signal, to a reflective mode of operation, the transitioning to the reflective mode including causing the internal light source to stop emitting light; and

displaying, responsive to transitioning to the reflective mode, at least one image by outputting data signals indicative of desired states of the plurality of light modulators to the plurality of light modulators to modulate light originating from the ambient light source.

35. The method of claim 34, wherein the second signal is based at least in part on detected ambient light.

36. The method of claim 34, wherein displaying at least one image in the transmissive mode includes modulating light in accordance with a first number of grayscale divisions for the image, and wherein displaying at least one image in the transflective or reflective modes includes modulating light in accordance with a second number of grayscale divisions, wherein the second number of grayscale divisions is less than the first number of grayscale divisions.

37. The method of claim 34, wherein displaying at least one image in the reflective mode includes at least one of modulating the image as a black and white image, and modulating light with at least 3 grayscale divisions.

38. The method of claim 34, wherein displaying at least one image in the transmissive mode includes modulating the light according to a first frame rate.

39. The method of claim 38, wherein displaying at least one image in the transflective or reflective modes includes modulating light in accordance with a second frame rate, wherein the second frame rate that is less than the first frame rate.

40. The method of claim 34, wherein transitioning to the reflective mode of operation includes loading, from a memory, operating parameters corresponding to the reflective mode.

41. The method of claim 34, wherein displaying at least one image in the reflective mode includes converting a color image into a black and white image for display.

42. The method of claim 34, wherein displaying at least one image in the transmissive mode includes modulating the plurality of light modulators according to a first sequence of timing signals which control the loading of image data to the plurality of light modulators.

43. The method of claim 42, wherein displaying at least one image in the transflective or reflective modes includes modulating the plurality of light modulators according to the same first sequence of timing signals which control the loading of image data to the plurality of light modulators.

44. The method of claim 42, wherein displaying at least one image in the transflective or reflective modes includes modulating the plurality of light modulators according to a second sequence of timing signals that is different from the first sequence.

45. The method of claim 44, wherein displaying at least one image in the transflective or reflective modes includes loading a subset of image data to the plurality of light modulators.

46. The method of claim 33, further including transitioning to an operating mode associated with a display of at least one image with more colors than another operating mode.

47. The method of claim 33, further including deriving the first signal from at least one of information to be displayed by the display apparatus and an amount of energy stored in a battery.

48. The method of claim 33, wherein decreasing the first intensity of the light source during the transition to the transflective mode of operation includes decreasing the first intensity such that at least about 30% of the light modulated by the plurality of light modulators originates from the ambient light source.

49. The method of claim 33, wherein the first signal is based at least in part on detected ambient light.

50. The method of claim 49, wherein the internal light source includes at least first and second light sources corresponding to different colors, and wherein the controller measures at least one color component of the detected ambient light, and adjusts the first intensity of at least one of the first and second light sources based on the measurement of the at least one color component of the detected ambient light.

51. The method of claim 33, wherein displaying at least one image in the transflective mode includes at least one of modulating the image as a black and white image, and modulating light with at least 3 grayscale divisions.

52. The method of claim 33, wherein displaying at least one image in the transflective mode includes modulating light to form a color image, and wherein the image is modulated with only 1 grayscale division per color.

53. The method of claim 33, wherein displaying at least one image in the transflective mode includes modulating light to form a color image, and wherein the image is modulated with at least 2 grayscale divisions per color.

54. The method of claim 33, wherein the light emitted by the internal light source passes through a plane defined by the plurality of light modulators.

55. A method for controlling a display apparatus, comprising:

displaying, by the display apparatus, at least one image in a transmissive mode of operation by causing an internal light source to emit light at a first intensity and by outputting data signals indicative of desired states of a plurality of light modulators such that the plurality of light modulators modulate the light emitted by the internal light source at the first intensity, each of the plurality of light modulators including at least one microelectromechanical systems (MEMS)-based shutter;

detecting a first signal configured to cause a transition from the transmissive mode of operation;

transitioning, in response to the first signal, to a transflective mode of operation, the transitioning including decreasing the intensity of the internal light source from the first intensity to a second intensity; and

displaying, responsive to transitioning to the transflective mode, at least one image in the transflective mode of operation by outputting data signals indicative of desired states of the plurality of light modulators such that the plurality of light modulators modulate light originating from an ambient light source and the light originating from the internal light source at the second intensity.

56. The method of claim 55, each of the plurality of light modulators further including:

a metal layer having at least one aperture defined therein; and

at least one electrode;

the MEMS-based shutter being translatable over the at least one aperture between at least an open position in which the shutter allows light to pass through the at least one aperture and a closed position in which the shutter blocks light from passing through the at least one aperture, the position of the MEMS-based shutter being based on an electrical potential between the MEMS-based shutter and the at least one electrode.

57. The method of claim 56, the metal layer having a front-facing surface and a rear-facing reflective surface, each of the plurality of light modulators further including:

a second reflective layer having a front-facing reflective surface; and

an optical cavity between the metal layer and the second reflective layer, the front-facing reflective surface of the second reflective layer and the rear-facing reflective surface of the metal layer capable of recycling light within the optical cavity.

58. The method of claim 57, the internal light source being configured to emit the light into the optical cavity.

59. The method of claim 58, each of the plurality of light modulators further including:

one or more transflective elements within a region defined by the at least one aperture.

60. The method of claim 59, wherein, while in the transflective mode of operation:

the MEMS-based shutter is configured to enable at least a portion of the ambient light to enter the optical cavity through the at least one aperture in regions between the one or more transflective elements or in regions between the one or more transflective elements and the metal layer; and

the optical cavity is configured to recycle the ambient light and to emit the recycled ambient light through the at least one aperture.

61. The method of claim 59, wherein, while in the transflective mode of operation the MEMS-based shutter is configured to enable at least a portion of the ambient light to reflect off of the one or more transflective elements.