Homogenizing lens array for display imaging
In described examples, a system (e.g., a projection system) can include a diffractive optical element adapted to be illuminated by at least one coherent light beam. A lens array is coupled to receive a diffracted beam of light from the diffractive optical element. The lens array includes a first and a second array lens. The first array lens is coupled to receive a first sector of a pattern of illumination of the diffracted beam of light, and the second array lens is coupled to receive a second sector of the pattern of illumination of the diffracted beam of light. A spatial light modulator is coupled to receive overlapping diffracted beams of light from the first and second array lenses to form an image beam.
1. A system, comprising:
a phase light modulator (PLM) comprising a two-dimensional array of pixels, the PLM adapted to be optically coupled to a coherent light beam illuminator, the PLM configured to generate a diffracted pattern comprising a first diffracted beam of light and a second diffractive beam of light responsive to an incident coherent light beam received from the coherent light beam illuminator;
a lens array optically coupled to the PLM, the lens array comprising:
a first array lens configured to receive the first diffracted beam of light and to produce a first overlapping diffracted beam of light responsive to the first diffracted beam of light;
a second array lens configured to receive the second diffracted beam of light and to produce a second overlapping diffracted beam of light responsive to the second diffracted beam of light; and
a spatial light modulator optically coupled to the lens array, the spatial light modulator configured to form an image beam responsive to the first overlapping diffracted beam of light and the second overlapping diffracted beam of light.
2. The system of claim 1 , further comprising a projection focusing element optically coupled to the spatial light modulator, the projection focusing element configured to focus the image beam.
3. The system of claim 1 , further comprising the coherent light beam illuminator, the coherent light beam illuminator including a light source configured to generate the incident coherent light beam.
4. The system of claim 3 , wherein the coherent light beam illuminator is a first coherent light beam illuminator, the light source is a first light source and the incident coherent light beam is a first incident coherent light beam, the system further comprising a second coherent light beam illuminator, the second coherent light beam illuminator including a second light source configured to generate a second incident coherent light beam, the second coherent light beam illuminator optically coupled to the lens array.
5. The system of claim 4 , wherein the first and second light sources are configured to be time-multiplexed to illuminate the lens array at different times.
6. The system of claim 4 , wherein the PLM is a first PLM, the system further comprising a second PLM optically coupled to the second coherent light beam illuminator, the second PLM configured to generate a third diffracted beam of light and a fourth diffracted beam of light responsive to the second incident coherent light beam, the first array lens configured to receive the third diffracted beam of light, the second array lens configured to receive the fourth diffracted beam of light.
7. The system of claim 1 , wherein the first diffracted beam of light and the second diffracted beam of light are in mutually distinct sectors.
8. The system of claim 1 , wherein the PLM is configured to generate a phase hologram.
9. The system of claim 8 , wherein the phase hologram includes dimensional features determined in response to a wavelength of the incident coherent light beam.
10. The system of claim 9 , wherein the phase hologram is configured to diffractively shift a Fourier-transform phase image to a location between diffraction orders.
11. The system of claim 9 , wherein the phase hologram is configured to diffractively shift a Fourier-transform phase image vertically and horizontally to a location between diffraction orders of a Fourier series of phase images.
12. The system of claim 1 , further comprising an inverting lens, the inverting lens optically coupled to the lens array, the lens array configured to focus the first overlapping diffracted beam of light and the second overlapping diffracted beam of light upon a same portion of the inverting lens.
13. The system of claim 1 , wherein the PLM is configured to produce a third diffracted beam of light and a fourth diffracted beam of light responsive to the incident coherent light beam, and wherein the lens array further includes a third array lens configured to receive the third diffracted beam of light, and wherein the lens array further includes a fourth array lens configured to receive the fourth diffracted beam of light.
14. The system of claim 13 , wherein the first array lens, the second array lens, the third array lens and the fourth array lens are arranged as a two-by-two lens array.
15. The system of claim 13 , further comprising a mask adjacent to the lens array, the mask arranged between adjacent array lenses of the first array lens, the second array lens, the third array lens and the fourth array lens, the first array lens adjacent to the second array lens and the fourth array lens, the second array lens adjacent to the first array lens and the third array lens, the third array lens adjacent to the second array lens and the fourth array lens, and the fourth array lens adjacent to the third array lens and the first array lens.
16. The system of claim 13 , further comprising a mask adjacent to the lens array, the mask configured to block a portion of a zero-order phase image of the diffracted pattern of illumination.
17. The system of claim 1 , further comprising the coherent light beam illuminator, the coherent light beam illuminator including a laser and fiber optics, the fiber optics coupled between the laser and the PLM.
18. The system of claim 1 , further comprising a diffuser optically coupled to the lens array, the diffuser having a moveable aperture.
19. A method, comprising:
generating, by a phase light modulator (PLM) comprising a two-dimensional array of pixels, a first diffracted beam of light and a second diffracted beam of light responsive to at least one coherent light beam incident on the PLM;
focusing, by a first array lens optically coupled to the PLM, the first diffracted beam of light to generate a first overlapping diffracted beam of light;
focusing, by a second array lens optically coupled to the PLM, the second diffracted beam of light to generate a second overlapping diffracted beam of light; and
modulating, by a spatial light modulator optically coupled to the PLM, the first overlapping diffracted beam of light and the second overlapping diffracted beam of light.
20. The method of claim 19 , further comprising:
diffusing, by a diffuser optically coupled to the PLM, to generate diffused light responsive to light received from the first array lens and the second array lens; and
projecting, by a projection focusing element optically coupled to the PLM, the diffused light.