Light field display device and method

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

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

(b) a scanner for scanning the beam across a two-dimensional angular field;

(c) a radiance modulator for modulating a radiance of the beam over time in accordance with a specified radiance value corresponding to the position on the display surface and an instantaneous direction of the beam within the angular field; and

(d) a focus modulator for modulating a focus of the beam over time.

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 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.

10. The device of claim 9 , 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.

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

12. The device of claim 11 , wherein the oscillation is resonant.

13. 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 a focus of the input beam;

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

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

14. 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) scanning the beam across a two-dimensional angular field;

(c) modulating a radiance of the beam over time in accordance with a specified radiance value corresponding to the position on the display surface and an instantaneous direction of the beam within the angular field; and

(d) modulating a focus of the beam over time.

15. The method of claim 14 , 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.

16. The method of claim 15 , wherein the specified depth is selected from the group comprising: a scene depth; and a fixation depth of a viewer of the surface.

17. The method of claim 14 , further comprising oscillating the display surface between at least two positions.

18. The method of claim 14 , 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 a focus of the input beam over time;

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

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