Retinal image display device

• US 20030156253A1
• Filed: 02/19/2003
• Published: 08/21/2003
• Est. Priority Date: 02/20/2002
• Status: Active Grant

• Current Assignee: Brother Kogyo Kabushiki Kaisha
• Original Assignee: Brother Kogyo Kabushiki Kaisha
• Inventors: Watanabe, Mitsuyoshi, Yamada, Shoji
• Granted Patent: US 7,497,574 B2
• Time in Patent Office: Days
• US Class Current: 351/200
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G09G 3/003 to produce spatial visual effects
• CPC Class Codes: G09G 3/025 with scanning or deflecting the beams in two directions or dimensions
• CPC Class Codes: H04N 9/3129 scanning a light beam on the display screen scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161

Abstract

A retinal image scanning device is provided with at least one light source that emits a light beam, an intensity modulating system that modulates the intensity of the light beam emitted by said at least one light source in accordance with a video signal, an optical system that directs the light beam to a pupil of an observer, a scanning system that scans the light beam in a first direction and in a second direction which is substantially perpendicular to the first direction so that a two-dimensional image frame defined by the first and second directions is formed on a retinal of the observer, and a wavefront curvature modulating system that modulates a wavefront curvature of the light beam when the light beam is scanned in at least one of the first direction and the second direction.

Claims

1. A retinal image scanning device, comprising:

at least one light source that emits a light beam;

an intensity modulating system that modulates the intensity of the light beam emitted by said at least one light source in accordance with a video signal;

an optical system that directs the light beam to a pupil of an observer;

a scanning system that scans the light beam in a first direction and in a second direction which is substantially perpendicular to the first direction so that a two-dimensional image frame defined by the first and second directions is formed on a retinal of the observer; and

a wavefront curvature modulating system that modulates a wavefront curvature of the light beam when the light beam is scanned in at least one of the first direction and the second direction.

2. The retinal image scanning device according to claim 1, wherein said wavefront curvature modulating system modulates the wavefront curvature of the light beam when it is scanned in the first direction.

3. The retinal image scanning device according to claim 2, wherein said wavefront curvature modulating system modulates the wavefront curvature of the light beam continuously while the light beam is scanned within a scanning range in the first direction.

4. The retinal image scanning device according to claim 3, wherein said wavefront curvature modulating system modulates the wavefront curvature trigonometrically.

5. The retinal image scanning device according to claim 4, wherein said wavefront curvature modulating system includes a movable element and a piezoelectric actuator, said piezoelectric actuator being controlled to move trigonometrically.

6. The retinal image scanning device according to claim 3, wherein said wavefront curvature modulating system modulates the wavefront curvature of the light beam in one direction during one scanning in the first direction.

7. The retinal image scanning device according to claim 6, wherein the wavefront curvature of the light beam at one end portion within a scanning range in the first direction corresponds to a close object, the wavefront curvature of the light beam at the other end portion within the scanning range in the first direction corresponding to a distant object.

8. The retinal image scanning device according to claim 3, wherein the wavefront curvature modulating system modulates the light beam such that the wavefront curvature of the light beam at a central portion within a scanning range in the first direction represents an object at a depth different from an object at a location represented by the wavefront curvature of the light beam at end portions within the scanning range in the first direction.

9. The retinal image scanning device according to claim 8, wherein the wavefront curvature of the light beam at a central portion within a scanning range in the first direction represents an object closer to an object at a location represented by the wavefront curvature of the light beam at end portions within the scanning range in the first direction.

10. The retinal image scanning device according to claim 1, wherein said wavefront curvature modulating system modulates the wavefront curvature of the light beam when it is scanned both in the first direction and in the second direction.

11. The retinal image scanning device according to claim 10, wherein said wavefront curvature modulating system modulates the wavefront curvature of the light beam continuously while the light beam is scanned within a scanning range both in the first direction and the second direction.

12. The retinal image scanning device according to claim 11, wherein said wavefront curvature modulating system modulates the wavefront curvature trigonometrically.

13. The retinal image scanning device according to claim 12, wherein said wavefront curvature modulating system includes a movable element and a piezoelectric actuator, said piezoelectric actuator being controlled to move trigonometrically.

14. The retinal image scanning device according to claim 11, wherein the wavefront curvature of the light beam at one end portion within a scanning range in the first direction corresponds to a close object, the wavefront curvature of the light beam at the other end portion within the scanning range in the first direction corresponding to a distant object.

15. The retinal image scanning device according to claim 14, wherein the first direction is a vertical direction.

16. The retinal image scanning device according to claim 14, wherein the wavefront curvature modulating system modulates the light beam such that the wavefront curvature of the light beam at a central portion within a scanning range in the second direction represents an object at a depth different from an object at a location represented by the wavefront curvature of the light beam at end portions within the scanning range in the second direction.

17. The retinal image scanning device according to claim 16, wherein the wavefront curvature of the light beam at a central portion within a scanning range in the second direction represents an object closer to an object at a location represented by the wavefront curvature of the light beam at end portions within the scanning range in the second direction.

18. The retinal image scanning device according to claim 16,

wherein, for the one end portion within the scanning range in the first direction, the wavefront curvature of the light beam in the second scanning direction is changed little, and

wherein, for the other end portion within the scanning range in the first direction, the wavefront curvature of the light beam in the second scanning direction is changed such that the wavefront curvature of the light beam at a central portion within the scanning range in the second direction represents an object at a depth different from an object at a location represented by the wavefront curvature of the light beam at end portions within the scanning range in the second direction.

19. The retinal image scanning device according to claim 18, wherein the first direction is a vertical direction and the second direction is a horizontal direction.

20. The retinal image scanning device according to claim 1, further comprising a synchronizing signal generating system that outputs a first synchronizing signal having a first frequency and a second synchronizing signal having a second frequency, said scanning system scans the light beam in the first direction and in the second direction synchronously with the first and second synchronizing signals, respectively.

21. The retinal image scanning device according to claim 20, wherein the second frequency is higher than the first frequency, said wavefront curvature modulating system modulating the wavefront curvature of the light beam such that the wavefront curvature changes little in the second direction, and the wavefront curvature changes in the first direction.

22. A retinal image scanning device, comprising:

at least one light source that emits a light beam;

an intensity modulating system that modulates the intensity of the light beam emitted by said at least one light source in accordance with a video signal;

an optical system that directs the light beam to a pupil of an observer;

a scanning system that scans the light beam in a first direction and in a second direction which is substantially perpendicular to the first direction so that a two-dimensional image frame defined by the first and second directions is periodically formed on a retinal of the observer; and

a wavefront curvature modulating system that modulates a wavefront curvature of the light beam,

wherein said wavefront curvature modulating system operates such that the wavefront curvature of the light beam forming the same image frame is substantially constant, the wavefront curvature of the light beam being changed only when frame image is switched to another frame.

23. The retinal image scanning device according to claim 22, wherein said wavefront curvature modulating system periodically changes the wavefront curvature of the light beam every time when the frame image is formed.

24. The retinal image scanning device according to claim 23, wherein said wavefront curvature modulating system modulates the wavefront curvature of the light beam so as to have first curvature and second curvature alternately as the image frames are formed one after another.

25. A retinal image scanning device, comprising:

at least one light source that emits a light beam;

an intensity modulating system that modulates the intensity of the light beam emitted by said at least one light source in accordance with a video signal;

an optical system that directs the light beam to a pupil of an observer;

a scanning system that scans the light beam in a first direction and in a second direction which is substantially perpendicular to the first direction so that a two-dimensional image frame defined by the first and second directions is formed on a retinal of the observer;

a synchronizing signal generating system that outputs a first synchronizing signal having a first frequency and a second synchronizing signal having a second frequency, said scanning system scans the light beam in the first direction and in the second direction synchronously with the first and second synchronizing signals, respectively; and

a wavefront curvature modulating system that modulates a wavefront curvature of the light beam synchronously with the first synchronizing signal when the light beam is scanned in the first direction.

26. The retinal image scanning device according to claim 25, wherein a first period, which is a reciprocal number of the first frequency, of the first synchronizing signal is substantially equal to a period of modulation, in the first direction, performed by said wavefront modulating system.

27. The retinal image scanning device according to claim 25, wherein a first period, which is a reciprocal number of the first frequency, of the first synchronizing signal is substantially a half a period of modulation, in the first direction, performed by said wavefront modulating system.

28. The retinal image scanning device according to claim 25, wherein a second period, which is a reciprocal number of the second frequency, of the second synchronizing signal is substantially equal to a period of modulation, in the second direction, performed by said wavefront modulating system.

29. The retinal image scanning device according to claim 28, wherein a first period, which is a reciprocal number of the first frequency, of the first synchronizing signal is substantially a half a period of modulation, in the first direction, performed by said wavefront modulating system.