Fiber optic ribbon display

• US 5,546,492 A
• Filed: 12/15/1994
• Issued: 08/13/1996
• Est. Priority Date: 01/28/1994
• Status: Expired due to Term

• Current Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Hughes Training, Inc.
• Inventors: Sisodia, Ashok, Ansley, David A.
• Primary Examiner(s): Lee, John D.
• Application Number:
  US08/356,981
• Time in Patent Office: 607 Days
• Field of Search: 385/114-119, 385/147, 359/197-199, 359/201, 359/204, 359/209, 359/618, 359/630-633, 340/815.42, 340/815.43, 340/815.45, 345/7-9, 345/30-32, 348/115, 348/804, 358/901.1
• US Class Current: 385/116
• CPC Class Codes: G02B 2027/014 comprising information/image processing systems
• CPC Class Codes: G02B 2027/0152 involving arrangement aiming to get lighter or better balanced devices
• CPC Class Codes: G02B 2027/0154 with movable elements
• CPC Class Codes: G02B 26/103 having movable or deformable optical fibres, light guides or waveguides as scanning elements light guides per se G02B6/00
• CPC Class Codes: G02B 27/0149 characterised by mechanical features G02B27/0176 takes precedence
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• CPC Class Codes: G02B 6/06 the relative position of the fibres being the same at both ends, e.g. for transporting images
• CPC Class Codes: H04N 9/3132 using one-dimensional electronic spatial light modulators
• CPC Class Codes: H04N 9/3138 using arrays of modulated light sources electroluminescent display devices G09G3/30

Abstract

A lightweight fiber optic television display useful for front and rear projection systems. An array of pixels such as a fiber optic (FO) ribbon has an input end which receives input light illuminating the pixels so as to create a first dimension of the display. The output end of the FO ribbon is moved relative to the observer to create a second dimension. The FO ribbon is clamped by a clamp near the output end and vibrated by a driver so that the output end of the ribbon is moved to obtain the second dimension. A lens is disposed between the vibrating end of the FO ribbon and a projection screen, and images the two dimensional image formed by the vibrating output end of the ribbon onto the screen. The projection screen may be either a rear or front projection screen. The FO ribbon may include a single row of fibers, or multiple rows to improve the image quality.

Claims

1. A two-dimensional fiber optic projection display system, comprising:

an array of flexible light conductors arranged in a ribbon having an input end and an output end, said array of flexible light conductors comprising a plurality of rows of optical fibers, wherein fibers in a given row are offset relative to corresponding fibers in an adjacent row to provide overlap of output ends of said light conductors and improve image quality;

means for injecting light into said input end of said ribbon to create a first dimension of said two-dimensional display;

means for moving said output end of said ribbon, said means comprising;

clamping means for clamping said ribbon at a location spaced from said output end to create a cantilevered ribbon section; and

driver means for vibrating said cantilevered ribbon section to deflect said output end of said ribbon;

a projection screen; and

means for imaging an image produced by said vibrating output end of said ribbon onto said projection screen for viewing by an observer.

2. The display system of claim 1 wherein said imaging means comprises an optical lens interposed between said output end of said ribbon and said projection screen.

3. The display system of claim 1 wherein said projection screen is a rear projection screen, wherein said imaging means projects light from said output end of said ribbon onto a first surface of said screen, and said observer views said image at a second opposite surface of said screen, wherein said display system is a rear projection system.

4. The display system of claim 1 wherein said projection screen is a front projection screen wherein said imaging means projects light from said output end of said ribbon onto a first front surface of said screen, and said observer views said image at said first front surface.

5. The display system of claim 1 wherein said driver means comprising first and second piezo ceramic slices arranged in opposite polarization and sandwiched to respective top and bottom surface regions of the cantilevered ribbon section, and a piezo electric exciter for exciting the first and second piezo ceramic slices, said exciter for causing the first slice to contract while causing the second slice to expand to achieve motion of the ribbon section in a first direction, and for causing the first slice to expand and the second slice to contract to achieve motion of the ribbon section in a second direction.

6. The display system of claim 1 further comprising a counterbalancing mass, and means for vibrating said counterbalancing mass in antiphase to vibrational movement of said cantilevered ribbon section to reduce vibration induced in said clamping means as a result of said vibrational movement of said cantilevered ribbon section.

7. The display system of claim 6 wherein said counterbalancing mass has a mass value substantially equal to a mass value associated with said ribbon section, and said counterbalancing mass is supported for swinging movement about a pivot point in an equal and opposite movement to vibrational movement of a center of mass of said cantilevered ribbon section.

8. The display system of claim 1 wherein said display has a pixel pitch characteristic, said plurality of aligned rows consists of a first row and a second row separated by a spacing of twice said pitch.

9. The display system of claim 8 wherein optical fibers within each said first and second row are separated by a nominal separation distance of twice said pitch.

10. The display system of claim 1 wherein said display has a pixel pitch characteristic, said plurality of aligned rows consists of first, second, third and fourth rows, and wherein adjacent rows are separated by a nominal spacing of four times said pixel pitch.

11. The display system of claim 1 wherein said light injecting means comprises a plurality of light emitting diodes.

12. The display system of claim 1 wherein said cantilevered ribbon section is characterized by a natural resonant frequency, and said driver means vibrates said ribbon section substantially at said resonant frequency.

13. The display system of claim 12 wherein length, width and thickness dimensions of said ribbon section are selected so as to provide a desired natural resonant frequency.

14. The display system of claim 13 wherein said display is characterized by a television field rate, and said driver means comprises means for vibrating said ribbon section at said television field rate.

15. The display system of claim 14 wherein said natural resonant frequency of said cantilevered ribbon section is substantially equal to said television field rate.

16. The display system of claim 1 wherein said display is characterized by a television field rate, and said driver means comprises means for vibrating said ribbon section at said television field rate.

17. The display system of claim 16 further comprising means for sensing said deflection of said output end of said ribbon and means responsive to said sensing means for controlling said driver means to synchronize said deflection to operation of said light injecting means.

18. The display system of claim 17 wherein said sensing means comprises a photodetector disposed to receive light from said output end of said ribbon.

19. The display system of claim 1 wherein said light conductors comprise optical fibers.

20. The display system of claim 19 wherein said optical fibers are high numerical aperture fibers.

21. The display system of claim 1 wherein said light injecting means comprises means for scanning a modulated light beam across said ends of said light conductors at said input end of said ribbon.

22. The display system of claim 21 wherein said light injecting means further comprises a laser for generating a laser light beam and means for amplitude modulating said beam to produce said modulated light beam.

23. The display system of claim 1 wherein said cantilevered ribbon section is characterized by a center of mass location which moves as said ribbon section is vibrated, and wherein said driver means has a driver mass associated therewith, said driver means being operated so as to move said driver mass in a direction opposite to movement of said center of mass location of said ribbon, thereby reducing vibration.

24. The display system of claim 23 wherein said center of mass location is moved along an arc during said vibration of said ribbon section, and wherein said driver mass is moved along an arc during operation thereof.

25. The display system of claim 1 further comprising a screen scattering coating applied at said output end of said ribbon.

26. A two-dimensional fiber optic display system, comprising:

an array of flexible light conductors arranged in a ribbon having an input end and an output end;

means for injecting light into said input end of said ribbon to create a first dimension of said two-dimensional display;

means for moving said output end of said ribbon to create said second dimension, said means comprising;

clamping means for clamping said ribbon at a location spaced from said output end to create a cantilevered ribbon section; and

driver means for vibrating said cantilevered ribbon section to deflect said output end of said ribbon, said driver means comprising first and second piezo ceramic slices arranged in opposite polarization and sandwiched to respective top and bottom surface regions of the cantilevered ribbon section, and a piezo electric exciter for exciting the first and second piezo ceramic slices, said exciter for causing the first slice to contract while causing the second slice to expand to achieve motion of the ribbon section in a first direction, and for causing the first slice to expand and the second slice to contract to achieve motion of the ribbon section in a second direction.

27. A two-dimensional fiber optic display system, comprising:

an array of flexible light conductors arranged in a ribbon having an input end and an output end;

means for injecting light into said input end of said ribbon to create a first dimension of said two-dimensional display;

means for moving said output end of said ribbon to create said second dimension, said means comprising;

clamping means for clamping said ribbon at a location spaced from said output end to create a cantilevered ribbon section; and

driver means for vibrating said cantilevered ribbon section to deflect said output end of said ribbon; and

dynamic counterbalancing apparatus for dynamically counterbalancing said system to minimize vibration imparted to said clamping means as a result of vibrational movement of said cantilevered ribbon section, said counterbalancing apparatus including a counter-balancing mass and a means for vibrating said counter-balancing mass in antiphase to the vibrational movement of said cantilevered ribbon section.

28. The display system of claim 27 wherein said driver means comprising first and second piezo ceramic slices arranged in opposite polarization and sandwiched to respective top and bottom surface regions of the cantilevered ribbon section, and a piezo electric exciter for exciting the first and second piezo ceramic slices, said exciter for causing the first slice to contract while causing the second slice to expand to achieve motion of the ribbon section in a first direction, and for causing the first slice to expand and the second slice to contract to achieve motion of the ribbon section in a second direction.

29. The display system of claim 27 wherein said array of flexible light conductors is a single row of optical fibers.

30. The display system of claim 29 wherein said light injecting means comprises a laser light source.

31. The display system of claim 27 wherein said array of flexible light conductors comprises a plurality of rows of optical fibers, wherein fibers in a given row are offset relative to corresponding fibers in an adjacent row to provide overlap between output ends of said flexible light conductors.

32. The display system of claim 31 wherein said display has a pixel pitch characteristic, said plurality of aligned rows consists of a first row and a second row separated by a spacing of twice said pitch.

33. The display system of claim 32 wherein optical fibers within each said first and second row are separated by a nominal separation distance of twice said pitch.

34. The display system of claim 31 wherein said display has a pixel pitch characteristic, said plurality of aligned rows consists of first, second, third and fourth rows, and wherein adjacent rows are separated by a nominal spacing of four times said pixel pitch.

35. The display system of claim 31 wherein said light injecting means comprises a plurality of light emitting diodes.

36. The display system of claim 27 wherein said cantilevered ribbon section is characterized by a natural resonant frequency, and said driver means vibrates said ribbon section substantially at said resonant frequency.

37. The display system of claim 36 wherein length, width and thickness dimensions of said ribbon section are selected so as to provide a desired natural resonant frequency.

38. The display system of claim 37 wherein said display is characterized by a television field rate, and said driver means comprises means for vibrating said ribbon section at said television field rate.

39. The display system of claim 38 wherein said natural resonant frequency of said cantilevered ribbon section is substantially equal to said television field rate.

40. The display system of claim 27 wherein said display is characterized by a television field rate, and said driver means comprises means for vibrating said ribbon section at said television field rate.

41. The display system of claim 40 further comprising means for sensing said deflection of said output end of said ribbon and means responsive to said sensing means for controlling said driver means to synchronize said deflection to operation of said light injecting means.

42. The display system of claim 41 wherein said sensing means comprises a photodetector disposed to receive light from said output end of said ribbon.

43. The display system of claim 27 wherein said light conductors comprise optical fibers.

44. The display system of claim 43 wherein said optical fibers are high numerical aperture fibers.

45. The display system of claim 27 wherein said light injecting means comprises means for scanning a modulated light beam across said ends of said light conductors at said input end of said ribbon.

46. The display system of claim 45 wherein said light injecting means further comprises a laser for generating a laser light beam and means for amplitude modulating said beam to produce said modulated light beam.

47. The display system of claim 27 wherein said cantilevered ribbon section is characterized by a center of mass location which moves as said ribbon section is vibrated, and wherein said driver means has a driver mass associated therewith, said driver means being operated so as to move said driver mass in a direction opposite to movement of said center of mass location of said ribbon, thereby reducing vibration.

48. The display system of claim 47 wherein said center of mass location is moved along an arc during said vibration of said ribbon section, and wherein said driver mass is moved along an arc during operation thereof.

49. The display system of claim 27 further comprising a screen scattering coating applied at said output end of said ribbon.

50. The display system of claim 27 wherein said counterbalancing mass has a mass value substantially equal to a mass value associated with said ribbon section, and said counterbalancing mass is supported for swinging movement about a pivot point in an equal and opposite movement to vibrational movement of a center of mass of said cantilevered ribbon section.