Light Field Display Device and Method

• US 20140240809A1
• Filed: 05/02/2014
• Published: 08/28/2014
• Est. Priority Date: 08/04/2012
• Status: Active Grant

• Current Assignee: Vergent Research Pty., Ltd.
• Original Assignee: Paul Lapstun
• Inventors: Lapstun, Paul
• Granted Patent: US 9,456,116 B2
• Time in Patent Office: Days
• US Class Current: 359/198.1
• CPC Class Codes: G02B 26/08 for controlling the direction of light in light guides G02B6/35
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 26/0875 by means of one or more refracting elements
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 27/0075 with means for altering, e.g. increasing, the depth of field or depth of focus
• CPC Class Codes: G02B 27/0093 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
• CPC Class Codes: G02B 30/10 using integral imaging methods
• CPC Class Codes: G02B 30/27 involving lenticular arrays
• CPC Class Codes: G02F 1/11 based on acousto-optical elements, e.g. using variable diffraction by sound or like mechanical waves acousto-optical deflection G02F1/33
• CPC Class Codes: G02F 1/29 for the control of the position or the direction of light beams, i.e. deflection
• CPC Class Codes: G02F 1/294 Variable focal length devices
• CPC Class Codes: G02F 1/33 Acousto-optical deflection devices circuit or control arrangements therefor G02F1/113
• CPC Class Codes: G06T 19/006 Mixed reality object pose determination, tracking or camera calibration for mixed reality G06T7/00
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2354/00 Aspects of interface with display user
• CPC Class Codes: G09G 2360/141 the light conveying information used for selecting or modulating the light emitting or modulating element
• CPC Class Codes: G09G 3/003 to produce spatial visual effects
• CPC Class Codes: G09G 3/02 by tracing or scanning a light beam on a screen
• CPC Class Codes: G09G 5/10 : Intensity circuits
• CPC Class Codes: H04N 13/243 : using three or more 2D image sensors
• CPC Class Codes: H04N 13/302 : for viewing without the aid of special glasses, i.e. using autostereoscopic displays
• CPC Class Codes: H04N 13/383 : for tracking with gaze detection, i.e. detecting the lines of sight of the viewer's eyes
• CPC Class Codes: H04N 23/54 : Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
• CPC Class Codes: H04N 23/56 : provided with illuminating means
• CPC Class Codes: H04N 23/61 : based on recognised objects
• CPC Class Codes: H04N 23/67 : Focus control based on electronic image sensor signals
• CPC Class Codes: H04N 23/951 : by using two or more images to influence resolution, frame rate or aspect ratio
• CPC Class Codes: H04N 23/957 : Light-field or plenoptic cameras or camera modules
• CPC Class Codes: H04N 25/745 : Circuitry for generating timing or clock signals

Abstract

The present invention provides a light field display device (300) comprising an array of light field display elements (310) populating a display surface, each display element (310) comprising: a beam generator (522) for generating an output beam of light; a radiance modulator (524) for modulating the radiance of the beam over time; a focus modulator (530) for modulating the focus of the beam over time; and a scanner (504, 506) for scanning the beam across a two-dimensional angular field.

Claims

1. A light field display device comprising an array of light field display elements populating a display surface, each display element comprising:

(a) a beam generator for generating an output beam of light;

(b) a radiance modulator for modulating the radiance of the beam over time;

(c) a focus modulator for modulating the focus of the beam over time; and

(d) a scanner for scanning the beam across a two-dimensional angular field.

2. The device of claim 1, wherein the beam generator comprises at least one light emitter selected from the group comprising:

a laser;

a laser diode;

a light-emitting diode;

a fluorescent lamp; and

an incandescent lamp.

3. The device of claim 1, wherein the beam generator comprises multiple light emitters with different emission spectra, the light emitters selected from the group comprising:

a laser;

a laser diode;

a light-emitting diode;

a fluorescent lamp; and

an incandescent lamp.

4. The device of claim 1, wherein the radiance modulator is intrinsic to the beam generator.

5. The device of claim 1, wherein the radiance modulator is selected from the group comprising:

an acousto-optic modulator;

an absorptive electro-optic modulator; and

a refractive electro-optic modulator.

6. The device of claim 1, wherein the focus modulator is selected from the group comprising:

a liquid crystal lens;

a liquid lens;

a deformable membrane mirror;

a deformable-membrane liquid-filled lens;

an addressable lens stack; and

an electro-optic lens.

7. The device of claim 1, wherein the scanner is selected from the group comprising:

an electromechanical scanning mirror;

an addressable deflector stack;

an acousto-optic scanner; and

an electro-optic scanner.

8. The device of claim 1, wherein the scanner comprises a biaxial electromechanical scanning mirror with at least one drive mechanism selected from the group comprising:

an electrostatic drive mechanism;

a magnetic drive mechanism; and

a capacitive drive mechanism.

9. The device of claim 1, wherein the scanner comprises a biaxial electromechanical scanning mirror comprising:

a mirror, a platform, an inner frame, and an outer frame;

the mirror attached to the platform via a post, the platform attached to the inner frame via a first pair of hinges, and the inner frame attached to the outer frame via a second pair of hinges;

the first pair of hinges arranged substantially orthogonally to the second pair of hinges, thereby to allow biaxial movement of the mirror;

the extent of the mirror larger than the extent of the inner frame.

10. The device of claim 1, wherein the scanner comprises a first scanner for scanning the beam in a first direction and a second scanner for simultaneously scanning the beam in a second direction, the second direction substantially orthogonal to the first.

11. The device of claim 10, wherein the first and second scanners are selected from the group comprising:

an electromechanical scanning mirror;

an addressable deflector stack;

an acousto-optic scanner; and

an electro-optic scanner.

12. The device of claim 1, further comprising at least one actuator for oscillating the display surface between at least two positions.

13. The device of claim 12, wherein the oscillation is resonant.

14. The device of claim 1, wherein the scanner is further configured to scan an input beam across the two-dimensional angular field, each display element further comprising:

(f) an input focus modulator for modulating the focus of the input beam;

(g) a radiance sensor for sensing the radiance of the input beam; and

(h) a radiance sampler for sampling the radiance of the input beam.

15. A method for displaying a light field, the method comprising, for each of a set of positions on a display surface, the steps of:

(a) generating an output beam of light;

(b) modulating the radiance of the beam over time;

(c) modulating the focus of the beam over time; and

(d) scanning the beam across a two-dimensional angular field.

16. The method of claim 15, wherein the radiance-modulating step comprises modulating the radiance of the beam in accordance with a specified radiance value corresponding to the position on the display surface and the instantaneous direction of the scanned beam within the angular field.

17. The method of claim 15, wherein the focus-modulating step comprises modulating the focus of the beam in accordance with a specified depth value corresponding to the position on the display surface and the instantaneous direction of the scanned beam within the angular field.

18. The method of claim 17, wherein the specified depth is selected from the group comprising:

a scene depth; and

a fixation depth of a viewer of the surface.

19. The method of claim 15, further comprising oscillating the display surface between at least two positions.

20. The method of claim 15, wherein the scanning step further comprises scanning an input beam across the two-dimensional angular field, the method further comprising the steps of:

(f) modulating the focus of the input beam over time;

(g) sensing the radiance of the input beam over time; and

(h) sampling the radiance of the input beam at discrete times.