Helmet mounted display

• US 5,281,960 A
• Filed: 11/19/1991
• Issued: 01/25/1994
• Est. Priority Date: 11/19/1991
• Status: Expired due to Fees

• Current Assignee: Silhouette Technology Incorporated
• Original Assignee: Silhouette Technology Incorporated
• Inventors: Dwyer, Eugene J. III
• Primary Examiner(s): Oberley, Alvin E.
• Assistant Examiner(s): WU, XIAO MIN
• Application Number:
  US07/794,863
• Time in Patent Office: 798 Days
• Field of Search: 340/705, 340/795, 340/794, 340/796, 340/781, 340/754, 340/755, 340/762, 340/702, 358/103, 358/93, 358/901, 359/230, 359/245, 359/618
• US Class Current: 345/31
• CPC Class Codes: G09G 3/002 to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT

Abstract

An optical display system is disclosed having a preferred application in a helmet mounted heads-up display. The display system includes an image source (42-46) for generating an image which includes a plurality o fields sequentially displayed by the image source to form the image with a two-dimensional array of pixels forming each field and the fields having a spatially modulated light intensity. An image display (50) is coupled to the image source for displaying the fields. The image display produces for each field a two-dimensional display having a fixed number of light emitting points (65) which are disposed along each dimension of the two-dimensional array with each light emitting point being spaced apart from adjacent light emitting points by a fixed distance. An actuator (52) is provided for moving the light emitting points in unison in a repeated pattern relative to a field of view of the displayed image with motion of each of the light emitting points along two axes during the repeated pattern delineating an area which is a fraction of an area of the displayed image produced by the image display. Movement of the light emitting points through successive positions of the repeated pattern is synchronized with the successive display of individual fields by the image source.

Claims

1. An optical display system comprising:

an image source for generating an image which includes a plurality of fields sequentially displayed by the image source to form the image with a two-dimensional array of pixels forming each field and the fields having a spatially modulated light intensity; and

an image display, coupled to the image source, for displaying the fields and including for each field a two-dimensional array having a fixed number of light emitting points with at least two light emitting points being disposed along each dimension of the two-dimensional array and each light emitting point being spaced apart from adjacent light emitting points by a fixed distance and an actuator for moving the light emitting points in unison in a repeated pattern relative to a field of view of the displayed image with motion of each of the light emitting points in two-dimensions during the repeated pattern delineating an area which is a fraction of an area of the displayed image produced by the image display and moving of the light emitting points through successive positions of the repeated pattern being synchronized with the successive display of individual fields by the image source.

2. An optical display system in accordance with claim 1 wherein:

the motion of the light emitting points in each of the two dimensions defining the area of the repeated pattern is through a plurality of the successive positions in displaying the fields of the image.

3. An optical display system in accordance with claim 2 wherein:

the image source comprises a cathode ray tube which modulates the light intensity of the spatially modulated fields.

4. An optical display system in accordance with claim 3 wherein:

each field is comprised of an n×

m array of pixels which are sequentially scanned by the cathode ray tube wherein n is a number of pixels of a field extending in a first dimension and m is a number of pixels extending in a second dimension.

5. An optical display system in accordance with claim 2 wherein:

the area delineated by the repeated pattern has a length of ax and a width of bx with a cross-sectional area of abx² with a being an integer equal to or greater than 2, b being an integer equal to or greater than 2 and x being dimension of the light emitting points with a position of each light emitting point during movement of the array of points through the repeated pattern by the actuator moving a distance equal to x along the length or along the width in synchronism with successive fields displayed by the image source.

6. An optical display system in accordance with claim 2 further comprising:

a fiber optical bundle having a plurality of individual fibers for transmitting light from the pixels of the image source to the light emitting points of the image display with an individual optical fiber of the bundle which is optically coupled to a pixel transmitting light between a pixel and a light emitting point.

7. An optical display system in accordance with claim 6 wherein:

the actuator moves an end of the fiber optic bundle coupled to the image display with the individual fibers of the end being spaced apart by the fixed distance.

8. An optical display system in accordance with claim 6 wherein:

the actuator refracts light emitted from ends of the fiber optical bundle to move the light emitting points through the repeated pattern.

9. An optical display system in accordance with claim 6 wherein:

the image display is part of a helmet mounted head-up display movable relative to the image source and provides images to be visually observed by a person wearing the helmet.

10. An optical display in accordance with claim 9 wherein:

the fiber optic bundle transmits an input optical image to the helmet back to the image source; and

further comprising

an image analyzer for analyzing the input image transmitted by the fiber optic bundle and controlling transmitting an image from the image source which was generated in response to an analysis of the transmitted image by the image analyzer.

11. An optical display in accordance with claim 10 wherein:

the input image is inputted from an optical system optically coupled to a field of view of the helmet; and

the transmitted image from the image source is an enhancement of an object in the field of view of the helmet.

12. An optical display system in accordance with claim 11 wherein:

the input image includes an infrared image of the field of view of the helmet; and

the transmitted image from the image source enhances the infrared image.

13. An optical display system in accordance with claim 6 further comprising:

a mask having an array of spaced apertures with an individual aperture being optically coupled to an individual fiber so that light emitted from one optical fiber passes through the aperture to provide a spacing between the light emitting points as viewed from the field of view which is defined by a spacing between the apertures; and

the mask is moved by the actuator through the repeated pattern to display the image.

14. An optical display in accordance with claim 13 wherein:

a dimension of the apertures is smaller than a dimension at an end of each fiber which is attached to the image display.

15. An optical display system in accordance with claim 2 wherein the actuator comprises:

at least one pair of piezoelectric elements for moving the light emitting points along orthogonal axes to produce the repeated pattern.

16. An optical display system in accordance with claim 2 wherein the actuator comprises:

at least one pair of electromagnetic coils for moving the light emitting points along orthogonal axes to produce the repeated pattern.

17. An optical display system in accordance with claim 2 wherein the actuator comprises:

at least one electrically activated light refractor optically coupled to a light output of the light emitting points at the image display for refracting the light output along orthogonal axes to produce the repeated pattern.

18. An optical display system in accordance with claim 2 wherein the actuator comprises:

at least one mirror optically coupled to a light output of the light emitting points at the image display for reflecting the light output along orthogonal axes to produce the repeated pattern.

19. An optical display system in accordance with claim 2 wherein the actuator comprises:

at least one lens optically coupled to a light output of the light emitting points at the image display for deflecting the light output along orthogonal axes to produce the repeated pattern.

20. An optical display system in accordance with claim 2 wherein the image source comprises:

a plurality of image producing devices with each device providing a part of each field with the parts being spatially non-overlapping.

21. An optical display system in accordance with claim 2 wherein the image source comprises:

a plurality of image producing devices with each device providing a different input image with the input images being spatially overlapping.

22. An optical display system in accordance with claim 21 wherein the input images comprise:

different colored images which are combined to produce a color displayed image of a single field of view.

23. An optical display system in accordance with claim 6 wherein the image display further comprises:

a mechanism for sensing a position of the fiber optic bundle at an end optically coupled to the light emitting points; and

wherein

the actuator is responsive to the sensed position for controlling movement of the actuator through the repeated pattern.

24. An optical display system in accordance with claim 23 wherein:

the mechanism for sensing comprises at least one input fiber of the bundle coupled to a light source and having an output which outputs light onto a target area which is fixed in position with respect to a viewing field of the display having reflective areas and at least one output optical fiber having an input disposed adjacent to the output of the input fiber having an output coupled to a photosensitive device with an output from the photosensitive device occurring when the light output of the at least one input fiber projects light which is reflected by one of the reflective areas to the input of the at least one output optical fiber which is processed by the actuator to provide a signal indicating the position of the light emitting points to control the repeated pattern.

25. An optical display system in accordance with claim 6 comprising:

a look-up table storing data of at least a transmission characteristic of individual fibers which are optically coupled to a pixel of the image source and a single light emitting point of the image display; and

wherein

the image source is responsive to the stored data to control a light intensity of light which is outputted by the image source to each fiber optically coupled to a pixel to provide at least a uniform light transmission characteristic for the fibers optically coupled to the light emitting points.

26. An optical display system in accordance with claim 25 wherein:

the at least one stored characteristic includes a multiplicative factor which is used to control the light intensity of the pixels to at least normalize the transmissivity of the fiber bundle.

27. An optical display system in accordance with claim 2 wherein the image display further comprises:

a mask having an array of spaced apertures which are spaced with an individual aperture being optically coupled with an individual pixel so that light emitted from one pixel passes through the aperture to the field of view to provide spacing between the light emitting points as viewed from the field of view which is defined by spacing between the apertures; and

the mask is moved by the actuator through the repeated pattern to display the image.

28. An optical display system in accordance with claim 27 wherein:

a maximum dimension of the apertures is smaller than a maximum dimension of a pixel optically aligned with the aperture.

29. An optical display system in accordance with claim 28 wherein:

the image source comprises a back lighted liquid crystal display.

30. An optical display system in accordance with claim 28 wherein:

the image source comprises an electroluminescent panel.

31. An optical display system in accordance with claim 28 wherein:

the image source comprises a CRT.

32. An optical display system in accordance with claim 2 wherein:

the image source comprises an array of light emitting diodes.

33. An optical display system in accordance with claim 2 wherein:

the image source and the image display are not movable relative to each other with only the actuator producing relative motion of the light emitting points with respect to the field of view.

34. An optical display system in accordance with claim 2 wherein:

the image source and the image display are fixed relative to each other and are not movable physically relative to each other.

35. An optical display system in accordance with claim 34 wherein the actuator comprises:

an array of light valves disposed between the image source and the field of view with a number of light valves being equal to the fixed number of light emitting points and with individual light valves being aligned with a single pixel and containing an array of apertures which each respectively correspond to a different position of a single light emitting point with each aperture being switchable to pass light from the display pixel; and

the system further comprising

a controller for synchronizing the display of the fields of the image and the switching of the apertures to produce movement of the light emitting points through the repeated pattern with each successive position of a light emitting point corresponding to a different field of the image source.

36. An optical display system in accordance with claim 34 wherein:

the image source comprises a light source, a filter which sequentially filters light produced by the light source with each sequential filtration filtering the light with a comb filter-like characteristic having spaced apart pass band characteristics with each sequential filtration having a different pass band characteristic with all of the filtrations collectively passing a spectrum of light comprising the image and an array of pixels being controlled by a system controller to pass the sequential filtration of light through the pixels to produce the image; and

the actuator comprises an array of light valves disposed between the image source and the field of view with individual light valves being aligned with a single pixel and containing an array of apertures which each respectively correspond to a different position of a single light emitting point with each aperture having a frequency pass band characteristic matching only one comb filter characteristic of one of the sequential filtrations; and

wherein

a system controller synchronizes selection of the filter characteristics and control of the pixels so that a single filtration and control of the pixels occurs with each field of the image.

37. An optical display system in accordance with claim 36 wherein:

the filter is a rotating filter wheel having a plurality of sectors with each sector having a different comb filter pass band characteristic.

40. A method in accordance with claim 29 wherein:

the area delineated by the repeated pattern has a length of ax and a width of bx with a cross-sectional area of abx² with a being an integer equal to or greater than 2, b being an integer equal to or greater than 2 and x being a dimension of the light emitting points with a position of each light emitting point during movement of the array of points through the repeated pattern by the actuator moving a distance equal to x along the length or along the width in synchronism with successive fields displayed by the image source.

38. A method of optical display of an image comprising:

generating an image including a plurality of fields which are sequentially displayed to form an image with a two-dimensional array of pixels forming each field having a spatially modulated light intensity;

optically coupling the fields of the image to a two-dimensional array of a fixed number of at least two light emitting points spaced apart by a fixed distance displaced along each dimension of the two-dimensional array; and

moving the light emitting points in unison in two dimensions in a repeated pattern relative to a field of view of the displayed image with movement of each light emitting point in two dimensions during the repeated pattern delineating an area which is a fraction of an area of the displayed image produced by the display of the image at the field of view and moving the light emitting points through successive positions of the repeated pattern being synchronized with the successive display of individual fields by the image source.

39. A method of optical display in accordance with claim 38 wherein:

the motion of the emitting points in each of the two dimensions defining the area of the repeated pattern is through a plurality of the successive positions in displaying the fields.

41. A method in accordance with claim 39 wherein:

a fiber optic bundle having a plurality of individual fibers transmits light from each of the pixels to the light emitting points with an individual optical fiber of the bundle which is optically coupled to a pixel transmitting light between a pixel and a light emitting point.

42. A method in accordance with claim 41 wherein:

an end of the fiber optic bundle coupled to the light emitting points is moved through the repeated pattern with the individual fibers of the end being spaced apart by the fixed distance.

43. A method in accordance with claim 41 wherein:

light emitted from each fiber of the fiber optical bundle is refracted to move the light emitting points through the repeated pattern.

44. A method in accordance with claim 39 wherein:

the fiber optic bundle transmits light from an image source to a helmet mounted head-up display which is movable relative to an image source and provides images to be visually observed by a person wearing the helmet.

45. A method in accordance with claim 44 further comprising:

transmitting an input optical image to the helmet through the fiber optic bundle to the image source;

analyzing the transmitted input image; and

transmitting from the image source through the fiber optic bundle to the helmet an image produced in response to the analyzed input image.

46. A method in accordance with claim 45 wherein:

the input optical image is optically coupled to a field of view of the helmet; and

the transmitted image from the image source is an enhancement of an object in a field of view of the helmet.

47. A method in accordance with claim 46 wherein:

the input image includes an infrared image from the field of view of the helmet.

48. A method in accordance with claim 41 further comprising:

transmitting light from the fiber optic bundle through an array of apertures which are spaced in a mask attached to an end of the fiber optic bundle with the individual apertures corresponding to the individual light emitting points and providing spacing between the light emitting points; and

moving the mask through the repeated pattern.

49. A method in accordance with claim 47 wherein:

a dimension of the apertures is smaller than a dimension of an end of each fiber which is attached to the mask; and

light transmitted through each aperture to the field of view is restricted by the aperture.

50. A method in accordance with claim 39 wherein:

the moving of the light emitting points in unison in the repeated pattern is along orthogonal axes.

51. A method in accordance with claim 50 wherein:

the movement along orthogonal axes is produced by at least one control element.

52. A method in accordance with claim 39 wherein:

the image is comprised of a plurality of spatially non-overlapping parts provided from different image producing devices.

53. A method in accordance with claim 39 wherein:

the image is comprised of spatially overlapping parts provided from different image producing sources.

54. A method in accordance with claim 39 wherein:

the image is comprised of different colored images provided from different image producing sources which are combined to produce a color displayed image.

55. A method in accordance with claim 41 further comprising:

sensing a position of the array of light emitting points; and

controlling the movement of the array of light emitting points through the repeated pattern in response to the sensed position.

56. A method in accordance with claim 39 further comprising:

controlling a light intensity of the pixels in response to a look up of stored data of at least a transmission characteristic of individual fibers which are optically coupled to a pixel and to a light emitting point to provide at least a uniform transmission characteristic for the optical fibers coupled between the pixels and the light emitting points.

57. A method in accordance with claim 56 wherein:

the stored characteristic is at least a multiplicative factor which is used to control the light intensity of the pixels to at least normalize the transmissivity of the fibers.

58. A method in accordance with claim 39 wherein:

the light emitting points are produced by passing light from each pixel through an associated aperture in a mask having spaced apertures optically coupled to the field of view so that light emitted from one pixel passes through one aperture to provide spacing between the light emitting points as viewed from the field of view which is defined by a space between apertures; and

the mask is moved through the repeated pattern to display the image.

59. A method in accordance with claim 58 wherein:

a maximum dimension of the apertures is smaller than a maximum dimension of a pixel optically aligned with the aperture.

60. A method in accordance with claim 39 wherein:

movement of the light emitting points is produced by relative motion between the light emitting points and the field of view.