Scanning method and architecture for display

• US 6,167,169 A
• Filed: 11/17/1998
• Issued: 12/26/2000
• Est. Priority Date: 09/09/1994
• Status: Expired due to Term

• Current Assignee: Gemfire Corp. (Medtronic Plc)
• Original Assignee: Gemfire Corp. (Medtronic Plc)
• Inventors: Bischel, William K., Brinkman, Michael J.
• Primary Examiner(s): Healy, Brian
• Application Number:
  US09/193,598
• Time in Patent Office: 770 Days
• Field of Search: 385/1-5, 385/7, 385/8, 385/10, 385/14, 385/15, 385/17, 385/40, 385/41, 385/42, 385/49, 385/50, 385/130, 385/131, 385/132, 385/11, 385/12, 385/13, 385/16, 385/18, 385/19, 385/20, 385/21, 385/22 , 385/147, 385/33, 385/901
• US Class Current: 385/4
• CPC Class Codes: G02F 1/011 in optical waveguides, not otherwise provided for in this subclass
• CPC Class Codes: G02F 1/3558 Poled materials, e.g. with periodic poling; Fabrication of domain inverted structures, e.g. for quasi-phase-matching [QPM]
• CPC Class Codes: G02F 1/377 in an optical waveguide structure
• CPC Class Codes: G02F 2201/30 grating
• CPC Class Codes: G02F 2201/305 diffraction grating
• CPC Class Codes: G02F 2201/307 Reflective grating, i.e. Bragg grating
• CPC Class Codes: G09F 9/305 being the ends of optical fibres G09F9/302 takes precedence
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

A method of scanning a plurality of display elements or pixels of a display and an apparatus capable of performing the method of scanning, allow energy propagating along a primary path to be diverted sequentially by a series of energy diverting devices to a plurality of secondary paths in a scanning direction depending upon the finite turn-on and turn-off times of the energy diverting devices.

Claims

1. A method for scanning elements of a display using a plurality of optical energy diverting devices disposed along a first optical path carrying optical energy from a first upstream position to a first downstream position, each diverting device having a respective on state and a respective off state and diverting optical energy from the first optical path to a respective display element when in the on state but not when in the off state, the method comprising the step of scanning the display elements at least in part by controlling the diverting devices along the first optical path such that the diverting devices reach their on states in upstream sequence.

2. A method according to claim 1, wherein each diverting device transitions from its off state to its on state in a respective finite time in response to assertion of a respective turn-on signal, and each diverting device transitions from its on state to its off state in a respective finite time in response to assertion of a respective turn-off signal, and wherein the step of scanning the display elements comprises the steps of:

(a) asserting a turn-on signal for a first one of the diverting devices;

(b) asserting a turn-off signal for the first diverting device; and

(c) asserting a turn-on signal for a second one of the diverting devices positioned upstream from the first diverting device along the first optical path, the second diverting device reaching the on state in response to the step of asserting the turn-on signal for the second diverting device, prior to the first diverting device reaching the off state in response to the step of asserting the turn-off signal for the first diverting device.

3. A method according to claim 2, wherein the step of asserting a turn-on signal for the second diverting device comprises the step of bringing the second diverting device to its on state after the first diverting device reaches its on state in response to the step of asserting a turn-on signal for the first diverting device.

4. The method of claim 3, wherein the second diverting device reaches its on state in response to the step of asserting the turn-on signal for the second diverting device, before the first diverting device reaches its off state in response to the step of asserting the turn-off signal for the first diverting device.

5. The method of claim 2, wherein the diverting devices further include a third diverting device positioned upstream of the second diverting device, and wherein the step of scanning the display elements comprises the further steps of:

diverting devices situated along all of the optical energy paths in the plurality of optical paths in parallel.

6. The method of claim 2, wherein the finite time in which the first diverting device transitions from its on state to its off state in response to the turn-off signal is greater than the finite time in which the second diverting device transitions from its off state to its on state in response to the turn-on signal.

7. The method of claim 2, further comprising the step of repeating steps (a) through (c) for scanning the display elements repetitively.

8. The method of claim 2, wherein the turn-on signal for a given one of the diverting devices is carried on the same conductor as the turn-off signal for the given diverting device.

9. The method of claim 1, wherein the first optical path is defined at least in part by an optical waveguide segment.

10. The method of claim 1, wherein the diverting devices comprise thermo-optic switches.

11. The method of claim 1, comprising the step of scanning the display elements repetitively by controlling the diverting devices along the first optical path such that the diverting devices reach their on states in a repeated upstream sequence.

12. A method according to claim 1, using a plurality of optical energy diverting devices arranged in an array, and a plurality of optical paths including the first optical path, each of the optical paths carrying optical energy from a respective upstream position to a respective downstream position, each diverting device being situated along one of the optical paths in the plurality of optical paths and having a respective on state and a respective off state, each diverting device diverting optical energy from the optical path along which it is situated to a respective display element when in the on state but not when in the off state, the step of scanning the display elements including the step of scanning the diverting devices situated along all of the optical energy paths in the plurality of optical paths in parallel.

13. A method for scanning elements of a display using a plurality of optical energy diverting devices disposed along a first optical path carrying optical energy from an upstream position to a downstream position, each of the diverting devices having a respective on state and a respective off state and diverting optical energy from the first optical path to a respective display element when in the on state but not when in the off state, each diverting device transitioning from its off state to its on state in a respective finite time in response to assertion of a respective turn-on signal, and each diverting device transitioning from its on state to its off state in a respective finite time in response to assertion of a respective turn-off signal, the method comprising the step of scanning the display elements at least in part by:

(a) asserting a turn-on signal for a first one of the diverting devices;

(b) asserting a turn-off signal for the first diverting device;

(c) asserting a turn-on signal for a second one of the diverting devices positioned downstream from the first diverting device along the first optical path, such that the second diverting device begins transitioning from its off state to its on state in response to the step of asserting the turn-on signal for the second diverting device, prior to the first diverting device reaching the off state in response to the step of asserting the turn-off signal for the first diverting device; and

(d) asserting a turn-off signal for the second diverting device, such that the second diverting device reaches its off state in response to the step of asserting a turn-off signal for the second diverting device, after the first diverting device reaches its off state in response to the step of asserting a turn-off signal for the first diverting device.

14. A method according to claim 13, wherein the second diverting device reaches the on state in response to the step of asserting the turn-on signal for the second diverting device, after the first diverting device reaches its on state in response to the step of asserting a turn-on signal for the first diverting device.

15. The method of claim 13, wherein the finite time in which the first diverting device transitions from its on state to its off state in response to the turn-off signal is less than the finite time in which the second diverting device transitions from its off state to its on state in response to the turn-on signal.

16. The method of claim 15, comprising the step of asserting the turn-on signal to all of the diverting devices such that all of the diverting devices are in their on states before the first diverting device reaches its off state in response to the step of asserting the turn-off signal for the first diverting device.

17. The method of claim 13, wherein the diverting devices further include a third diverting device positioned downstream of the second diverting device, and wherein the step of scanning the display elements comprises the further step of asserting the turn-on signal for the third diverting device such that the third diverting device reaches its on state after the second diverting device reaches its on state in response to the step of asserting the turn-on signal for the second diverting device but before the second diverting device reaches its off state in response to the step of asserting the turn-off signal for the second diverting device.

18. The method of claim 13, further comprising the step of repeating steps (a) through (d) for scanning the display elements repetitively.

19. The method of claim 13, wherein the first optical path is defined at least in part by an optical waveguide segment.

20. The method of claim 13, wherein the diverting devices comprise thermo-optic switches.

21. A method according to claim 13, using a plurality of optical energy diverting devices arranged in an array, and a plurality of optical paths including the first optical path, each of the optical paths carrying optical energy from a respective upstream position to a respective downstream position, each diverting device being situated along one of the optical paths and having a respective on state and a respective off state, and diverting optical energy from the optical path along which it is situated to a respective display element when in the on state but not when in the off state, the step of scanning the display elements including the further steps of:

(e) asserting a turn-on signal for a third one of the diverting devices along a second one of the optical paths;

(f) asserting a turnoff signal for the third diverting device such that the third diverting device reaches its off state no earlier than the first diverting device reaches its off state in response to the step of asserting a turn-off signal for the first diverting device, but before the second diverting device reaches its off state in response to the step of asserting a turn-off signal for the second diverting device.

22. The method of claim 13, wherein the turn-on signal for a given one of the diverting devices is carried on the same conductor as the turn-off signal for the given diverting device.

23. A method for scanning a plurality of display elements arranged in an array on a display, by selectively diverting optical energy using a plurality of optical energy diverting devices disposed along a plurality of optical paths each oriented in a first dimension of the array, each of the optical paths carrying optical energy from a respective upstream position to a respective downstream position on the optical path, each of the diverting devices capable of diverting optical energy when in an on state to a respective one of the display elements, the method comprising, within a scan of the display elements along the respective optical paths, the steps of:

(a) asserting a turn-on signal for a first one of the diverting devices on a first one of the optical paths;

(b) asserting a turn-off signal for the first diverting device on the first optical path;

(c) asserting a turn-on signal for a second one of the diverting devices positioned on the first optical path upstream of the first diverting device on the first optical path, the second diverting device reaching an on state in response to the step of asserting the turn-on signal for the second diverting device, prior to the first diverting device reaching an off state in response to the step of asserting the turn-off signal for the first diverting device; and

(d) no earlier than the step of asserting the turn-on signal for the first diverting device on the first optical path, but before the step of asserting the turn-on signal for the second diverting device on the first optical path, asserting the turn-on signal for a first one of the diverting devices on a second one of the optical paths.

24. The method of claim 23, further comprising the steps of:

asserting the turn-off signal for the first diverting device on the second optical path no earlier than the step of asserting the turn-off signal for the first diverting device on the first optical path; and

asserting the turn-on signal for a second one of the diverting devices positioned upstream of the first diverting device on the second optical path, the second diverting device on the second optical path reaching an on state in response to the step of asserting the turn-on signal for the second diverting device on the second optical path, prior to the first diverting device on the second optical path reaching an off state in response to the step of asserting the turn-off signal for the first diverting device on the second optical path.

25. The method of claim 24, wherein the step of asserting the turn-on signal for the first diverting device on the second optical paths occurs at the same time as the step of asserting the turn-on signal for the first diverting device on the first optical path,

wherein the step of asserting the turn-off signal for the first diverting device on the second optical path occurs at the same time as the step of asserting the turn-off signal for the first diverting device on the first optical path;

and

wherein the step of asserting the turn-on signal for the second diverting device on the second optical path occurs at the same time as the step of asserting the turn-on signal for the second diverting device on the first optical path.

26. The method of claim 25, further comprising the steps of:

asserting a turn-on signal for a third one of the diverting devices positioned upstream of the second diverting device on the first optical path, after the step of asserting the turn-on signal for the second diverting device on the first optical path; and

asserting a turn-on signal for a third one of the diverting devices positioned upstream of the second diverting device on the second optical path, no earlier than the step of asserting the turn-on signal for the third diverting device on the first optical path, after the step of asserting the turn-on signal for the second diverting device on the second optical path.

27. The method of claim 23, comprising the step of repeating steps (a) through (d) for each of a plurality of scans of the display elements.

28. The method of claim 24, wherein each of the diverting devices turns on in response to a respective turn-on control signal and reaching an on state at a finite time thereafter, and each of the diverting devices turns off in response to a respective turn-off signal and reaching an off state at a finite time thereafter;

wherein the step of asserting the turn-on signal for the second diverting device on the first optical path is performed before the first diverting device on the first optical path reaches its off state in response to the step of asserting the turn-off signal for the first diverting device on the first optical path; and

wherein the step of asserting the turn-on signal for the second diverting device on the second optical path is performed before the first diverting device on the second optical path reaches its off state in response to the step of asserting the turn-off signal for the first diverting device on the second optical path.

29. The method of claim 28, wherein the finite time of the first diverting device on the first optical path transitioning from its on state to its off state in response to the turn-off signal is greater than the finite time of the second diverting device on the first optical path transitioning from its off state to its on state in response to the turn-on signal;

and

wherein the finite time of the first diverting device on the second optical path transitioning from its on state to its off state in response to the turn-off signal is greater than the finite time of the second diverting device on the second optical path transitioning from its off state to its on state in response to the turn-on signal.

30. The method of claim 23, wherein the optical paths are defined at least in part by optical waveguide segments.

31. The method of claim 23, wherein the diverting devices comprise thermo-optical switches.

32. A method for scanning a plurality of optical energy diverting devices disposed on an optical path for selectively diverting optical energy from the optical path, the optical path capable of carrying optical energy from an upstream position to a downstream position, each of the diverting devices capable of turning on from an off state and reaching an on state at a finite turn-on time thereafter, and each of the diverting devices capable of turning off from an on state and reaching an off state at a finite turn-off time thereafter, the method comprising the step of:

scanning the diverting devices in the upstream direction if the finite turn-off time of each of the diverting devices reaching the off state from the on state is greater than the finite turn-on time of each of the diverting devices reaching the on state from the off state, and in the downstream direction if the finite turn-off time of each of the diverting devices reaching the off state from the on state is less than the finite turn-on time of each of the diverting devices reaching the on state from the off state.

33. Display apparatus comprising:

a plurality of display elements;

a plurality of optical energy diverting devices disposed along a first optical path to carry optical energy from a first upstream position to a first downstream position, each diverting device having a respective on state and a respective off state and diverting optical energy from the first optical path to a respective display element when in the on state but not when in the off state; and

a controller which scans the display elements by controlling the diverting devices along the first optical path such that the diverting devices reach their on states in upstream sequence.

34. The apparatus of claim 33, wherein each diverting device transitions from its off state to its on state in a respective finite time in response to assertion of a respective turn-on signal, and each diverting device transitions from its on state to its off state in a respective finite time in response to assertion of a respective turn-off signal, and wherein the controller:

(a) asserts a turn-on signal for a first one of the diverting devices;

(b) asserts a turn-off signal for the first diverting device; and

(c) asserts a turn-on signal for a second one of the diverting devices positioned upstream from the first diverting device along the first optical path, the second diverting device reaching the on state in response to the turn-on signal for the second diverting device, prior to the first diverting device reaching the off state in response to the turn-off signal for the first diverting device.

35. The apparatus of claim 34, wherein the assertion of the turn-on signal for the second diverting device brings the second diverting device to its on state after the first diverting device reaches its on state in response to the assertion of the turn-on signal for the first diverting device.

36. The apparatus of claim 34, wherein the diverting devices further include a third diverting device positioned upstream of the second diverting device, and wherein the controller during a scan further:

asserts the turn-off signal for the second diverting device; and

asserts the turn-on signal for the third diverting device such that the third diverting device reaches its on state after the second diverting device reaches its on state in response to the assertion of the turn-on signal for the second diverting device but before the second diverting device reaches its off state in response to the assertion of the turn-off signal for the second diverting device.

37. The apparatus of claim 34, wherein the finite time in which the first diverting device transitions from its on state to its off state in response to the turn-off signal is greater than the finite time in which the second diverting device transitions from its off state to its on state in response to the turn-on signal.

38. The apparatus of claim 34, further comprising a conductor which carries both the turn-on signal and the turn-off signal to a given one of the diverting devices.

39. The apparatus of claim 33, wherein the first optical path is defined at least in part by an optical waveguide segment.

40. The apparatus of claim 33, wherein the diverting devices comprise thermo-optic switches.

41. The apparatus of claim 33, wherein said controller scans the display elements repetitively by controlling the diverting devices along the first optical path such that the diverting devices reach their on states in a repeated upstream sequence.

42. The apparatus of claim 33, comprising:

a plurality of optical energy diverting devices arranged in an array;

a plurality of optical paths including the first optical path, each of the optical paths carrying optical energy from a respective upstream position to a respective downstream position, each diverting device being situated along one of the optical paths in the plurality of optical paths and having a respective on state and a respective off state, each diverting device diverting optical energy from the optical path along which it is situated to a respective display element when in the on state but not when in the off state,

wherein the controller scans the display elements by scanning the diverting devices situated along all of the optical energy paths in the plurality of optical paths in parallel.

43. Display apparatus comprising:

a plurality of display elements;

a plurality of optical energy diverting devices disposed along a first optical path carrying optical energy from an upstream position to a downstream position, each of the diverting devices having a respective on state and a respective off state and diverting optical energy from the first optical path to a respective display element when in the on state but not when in the off state, each diverting device transitioning from its off state to its on state in a respective finite time in response to assertion of a respective turn-on signal, and each diverting device transitioning from its on state to its off state in a respective finite time in response to assertion of a respective turn-off signal; and

a controller which scans the display elements at least in part by

(a) asserting a turn-on signal for a first one of the diverting devices;

(b) asserting a turn-off signal for the first diverting device;

(c) asserting a turn-on signal for a second one of the diverting devices positioned downstream from the first diverting device along the first optical path, such that the second diverting device begins transitioning from its off state to its on state in response to the assertion of the turn-on signal for the second diverting device, prior to the first diverting device reaching the off state in response to the assertion of the turn-off signal for the first diverting device; and

(d) asserting a turn-off signal for the second diverting device, such that the second diverting device reaches its off state in response to the assertion of a turn-off signal for the second diverting device, after the first diverting device reaches its off state in response to the assertion of a turn-off signal for the first diverting device.

44. The apparatus of claim 43, wherein the second diverting device reaches the on state in response to the assertion of the turn-on signal for the second diverting device, after the first diverting device reaches its on state in response to the assertion of a turn-on signal for the first diverting device.

45. The apparatus of claim 43, wherein the finite time in which the first diverting device transitions from its on state to its off state in response to the turn-off signal is less than the finite time in which the second diverting device transitions from its off state to its on state in response to the turn-on signal.

46. The apparatus of claim 45, wherein the controller asserts the turn-on signal to all of the diverting devices such that a plurality of the diverting devices are in their on states before the first diverting device reaches its off state in response to the assertion of the turn-off signal for the first diverting device.

47. The apparatus of claim 43, wherein the diverting devices further include a third diverting device positioned downstream of the second diverting device, and wherein the controller asserts the turn-on signal for the third diverting device such that the third diverting device reaches its on state after the second diverting device reaches its on state in response to the assertion of the turn-on signal for the second diverting device but before the second diverting device reaches its off state in response to the assertion of the turn-off signal for the second diverting device.

48. The apparatus of claim 43, wherein the first optical path is defined at least in part by an optical waveguide segment.

49. The apparatus of claim 43, wherein the diverting devices comprise thermo-optic switches.

50. The apparatus of claim 43, comprising:

a plurality of optical energy diverting devices arranged in an array;

a plurality of optical paths including the first optical path, each of the optical paths carrying optical energy from a respective upstream position to a respective downstream position, each diverting device being situated along one of the optical paths and having a respective on state and a respective off state, and diverting optical energy from the optical path along which it is situated to a respective display element when in the on state but not when in the off state,

wherein the controller scans the display elements further by

(e) asserting a turn-on signal for a third one of the diverting devices along a second one of the optical paths;

(f) asserting a turn-off signal for the third diverting device such that the third diverting device reaches its off state no earlier than the first diverting device reaches its off state in response to the assertion of a turn-off signal for the first diverting device, but before the second diverting device reaches its off state in response to the assertion of a turn-off signal for the second diverting device.

51. The apparatus of claim 43, further comprising a conductor which carries both the turn-on signal and the turn-off signal to a given one of the diverting devices.

52. Display apparatus comprising:

a plurality of display elements arranged in an array;

a plurality of optical energy diverting devices disposed along a plurality of optical paths each oriented in a first dimension of the array, each of the optical paths carrying optical energy from a respective upstream position to a respective downstream position on the optical path, each of the diverting devices capable of diverting optical energy when in an on state to a respective one of the display elements; and

a controller which scans the display elements at least in part by

(a) asserting a turn-on signal for a first one of the diverting devices on a first one of the optical paths;

(b) asserting a turn-off signal for the first diverting device on the first optical path;

(c) asserting a turn-on signal for a second one of the diverting devices positioned on the first optical path upstream of the first diverting device on the first optical path, the second diverting device reaching an on state in response to the assertion of the turn-on signal for the second diverting device, prior to the first diverting device reaching an off state in response to the assertion of the turn-off signal for the first diverting device; and

(d) no earlier than the assertion of the turn-on signal for the first diverting device on the first optical path, but before the assertion of the turn-on signal for the second diverting device on the first optical path, asserting the turn-on signal for a first one of the diverting devices on a second one of the optical paths.

53. Display apparatus comprising:

an optical path capable of carrying optical energy from an upstream position to a downstream position;

a plurality of optical energy diverting devices disposed on the optical path, each of the diverting devices capable of turning on from an off state and reaching an on state at a finite turn-on time thereafter, and each of the diverting devices capable of turning off from an on state and reaching an off state at a finite turn-off time thereafter; and

a controller which scans the diverting devices selectably in the upstream direction or the downstream direction.

54. The apparatus of claim 53, wherein the controller scans the diverting devices in the upstream direction if the finite turn-off time of each of the diverting devices reaching the off state from the on state is greater than the finite turn-on time of each of the diverting devices reaching the on state from the off state, and in the downstream direction if the finite turn-off time of each of the diverting devices reaching the off state from the on state is less than the finite turn-on time of each of the diverting devices reaching the on state from the off state.