Low-profile beam splitter
Examples of light projector systems and methods of use. A method can include providing an optical device having a first surface, a second surface normal to the first surface, and a third surface arranged at an angle to the second surface. The third surface can be reflective to light of a first state and transmissive to light of a second state. An input beam having the first state can be normally incident on the first surface. A transmissive diffractive optical element on the first surface can convert the input beam into at least a first diffracted beam directed toward the third surface, where it is reflected by the third surface in a direction substantially parallel to the first surface. The reflected first diffracted beam can be modulated with image information using a spatial light modulator to produce a modulated light beam having the second state.
1. A method of transmitting image information to a user, the method comprising:
providing an optical device comprising a first surface, a second surface normal to the first surface, and a third surface arranged at an angle to the second surface, the third surface being reflective to light of a first state and transmissive to light of a second state;
producing an input beam incident on the first surface, the input beam traveling normal to the first surface and having the first state;
providing a transmissive diffractive optical element on the first surface to convert the input beam into at least a first diffracted beam at a first diffraction angle such that the first diffracted beam is directed toward the third surface and is reflected by the third surface in a direction substantially parallel to the first surface;
modulating at least the reflected first diffracted beam with image information using a spatial light modulator, the spatial light modulator being configured to receive the reflected first diffracted beam normal to the spatial light modulator and to produce a modulated light beam having the second state;
receiving the modulated light beam using one or more projection optical components; and
projecting the image information to the user using the one or more projection optical components.
2. The method of claim 1 , further comprising collimating the input beam with a collimator disposed adjacent to the optical device.
3. The method of claim 1 , wherein the angle of the third surface with respect to the second surface is less than 45 degrees.
4. The method of claim 3 , wherein the angle of the third surface with respect to the second surface is about 30 degrees.
5. The method of claim 1 , wherein the first diffraction angle is greater than 0 degrees.
6. The method of claim 5 , wherein the first diffraction angle is about 30 degrees.
7. A method of transmitting image information to a user, the method comprising:
providing an optical device comprising a first surface, a second surface normal to the first surface and a third surface arranged at an angle with respect to the second surface, the third surface being reflective to light of a first state and transmissive to light of a second state;
producing a diverging input light beam incident onto the first surface, the diverging input light beam having the first state;
providing a reflective diffractive optical element on the first surface to convert the diverging input beam into at least a first collimated and diffracted beam at a first diffraction angle such that the first collimated and diffracted beam is directed toward the third surface and is reflected by the third surface in a direction substantially parallel to the first surface;
modulating at least the reflected first diffracted beam with image information using a spatial light modulator, the spatial light modulator configured to receive the reflected first diffracted beam normal to the spatial light modulator and to produce a modulated light beam having the second state;
receiving the modulated light beam using one or more projection optical components; and
projecting the image information to the user using the one or more projection optical components.
8. The method of claim 7 , further comprising using the reflective diffractive optical element to convert the diverging input beam into a second collimated and diffracted beam at a second diffraction angle such that the second collimated and diffracted beam is directed toward the second surface, is reflected by the second surface toward the third surface via total internal reflection, and is reflected by the third surface in the direction substantially parallel to the first surface.
9. The method of claim 7 , further comprising producing a plurality of angularly or laterally separated diverging input beams and using the reflective diffractive optical element to convert them into collimated and diffracted beams with a reduced amount of angular or lateral separation.
10. The method of claim 7 , wherein the angle of the third surface with respect to the second surface is less than 45 degrees.
11. The method of claim 10 , wherein the angle of the third surface with respect to the second surface is about 30 degrees.
12. The method of claim 7 , wherein the first diffraction angle is greater than 0 degrees.
13. The method of claim 12 , wherein the first diffraction angle is about 30 degrees.
14. A method of transmitting image information to a user, the method comprising:
providing an optical device comprising a first surface, a second surface normal to the first surface, and a third surface arranged at an angle to the second surface, the third surface being reflective to light of a first state and transmissive to light of a second state;
producing an input beam incident on the first surface, the input beam traveling normal to the first surface and having the first state;
providing a transmissive diffractive optical element on the first surface to convert the input beam into at least a first diffracted beam at a first diffraction angle such that the first diffracted beam is directed toward the second surface, is reflected by the second surface toward the third surface via total internal reflection, and is reflected by the third surface in a direction substantially parallel to the first surface;
modulating at least the reflected first diffracted beam with image information using a spatial light modulator, the spatial light modulator being configured to receive the reflected first diffracted beam normal to the spatial light modulator and to produce a modulated light beam having the second state;
receiving the modulated light beam using one or more projection optical components; and
projecting the image information to the user using the one or more projection optical components.
15. The method of claim 14 , further comprising collimating the input beam with a collimator disposed adjacent to the optical device.
16. The method of claim 14 , wherein the angle of the third surface with respect to the second surface is less than 45 degrees.
17. The method of claim 16 , wherein the angle of the third surface with respect to the second surface is about 30 degrees.
18. The method of claim 14 , wherein the first diffraction angle is greater than 0 degrees.
19. The method of claim 18 , wherein the first diffraction angle is about 30 degrees.
20. A method of transmitting image information to a user, the method comprising:
providing an optical device comprising a first surface, a second surface normal to the first surface and a third surface arranged at an angle with respect to the second surface, the third surface being reflective to light of a first state and transmissive to light of a second state;
producing a diverging input light beam incident onto the first surface, the diverging input light beam having the first state;
providing a reflective diffractive optical element on the first surface to convert the diverging input beam into at least a first collimated and diffracted beam at a first diffraction angle such that the first collimated and diffracted beam is directed toward the second surface, is reflected by the second surface toward the third surface via total internal reflection, and is reflected by the third surface in a direction substantially parallel to the first surface;
modulating at least the reflected first diffracted beam with image information using a spatial light modulator, the spatial light modulator configured to receive the reflected first diffracted beam normal to the spatial light modulator and to produce a modulated light beam having the second state;
receiving the modulated light beam using one or more projection optical components; and
projecting the image information to the user using the one or more projection optical components.
21. The method of claim 20 , further comprising using the reflective diffractive optical element to convert the diverging input beam into a second collimated and diffracted beam at a second diffraction angle such that the second collimated and diffracted beam is directed toward the third surface and is reflected by the third surface in the direction substantially parallel to the first surface.
22. The method of claim 20 , further comprising producing a plurality of angularly or laterally separated diverging input beams and using the reflective diffractive optical element to convert them into collimated and diffracted beams with a reduced amount of angular or lateral separation.
23. The method of claim 20 , wherein the angle of the third surface with respect to the second surface is less than 45 degrees.
24. The method of claim 23 , wherein the angle of the third surface with respect to the second surface is about 30 degrees.
25. The method of claim 20 , wherein the first diffraction angle is greater than 0 degrees.
26. The method of claim 25 , wherein the first diffraction angle is about 30 degrees.