Light field display device and method

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

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

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

(c) an angular reconstruction filter for inducing spread in the output beam substantially equal to an angular sampling period;

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

(e) a scanner for scanning the output 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 output beam in a first direction and a second scanner for simultaneously scanning the output 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 array 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 in an array, the steps of:

(a) generating an output beam of light;

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

(c) inducing spread in the output beam substantially equal to an angular sampling period;

(d) modulating a focus of the output beam over time; and

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

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

17. The method of claim 15 , wherein the focus-modulating step comprises modulating the focus of the output beam in accordance with a specified depth value corresponding to the position and an instantaneous direction of the scanned output 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 array.

19. The method of claim 15 , further comprising oscillating the array 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 a focus of the input beam over time; and

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

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