Securing a fresnel lens to a refractive optical element
A headset for virtual reality applications includes an optical element configured to modify light from an electronic display in the headset and to direct the modified light to a user. The optical element may include a Fresnel lens secured to a lens by securing the Fresnel lens to a mold and inserting a casting material into the mold so the casting material forms the lens and a portion of the casting material exists on and past an edge of the Fresnel lens. This encases the edge of the Fresnel lens in the casting material, securing the Fresnel lens to the lens.
1. A virtual reality headset comprising:
an optical block with one end adjacent to an exit pupil corresponding to a position of a user's eye when using the virtual reality headset, the optical block comprising:
an electronic display element opposite the exit pupil, the electronic display element projecting image light toward the exit pupil; and
a corrective optics block between the electronic display element and the exit pupil, the corrective optics block comprising a diffractive optical element and a refractive optical element, the corrective optics block configured to correct fixed pattern noise in the projected image light.
2. The virtual reality headset of claim 1 , wherein the diffractive optical element is a Fresnel lens.
3. The virtual reality headset of claim 1 , wherein the diffractive optical element has a higher density of grooves near its center.
4. The virtual reality headset of claim 1 , wherein the refractive optical element is a convex lens.
5. The virtual reality headset of claim 1 , wherein the corrective optics block is configured to slightly blur image light projected from sub-pixels of the electronic display element.
6. The virtual reality headset of claim 1 , wherein the diffractive optical element is secured to the refractive optical element via molded pins.
7. The virtual reality headset of claim 6 , wherein the molded pins are formed through an exterior portion of the diffractive optical element that is located outside of a field of view of the user when their eye is positioned at the exit pupil.
8. The virtual reality headset of claim 1 , wherein the corrective optical block is positioned at least 35 millimeters from the electronic display element.
9. The virtual reality headset of claim 1 , wherein an effective focal length of the corrective optics block is larger than a distance from the corrective optics block to the electronic display element.
10. The virtual reality headset of claim 1 , wherein the corrective optics block comprises a resin.
11. The virtual reality headset of claim 1 , further comprising:
a second optical block with one end adjacent to a second exit pupil corresponding to a position of a user's second eye when using the virtual reality headset, the second optical block comprising:
a second electronic display element opposite the second exit pupil, the second electronic display element projecting image light toward the second exit pupil; and
a second corrective optics block between the second electronic display element and the second exit pupil, the second corrective optics block comprising a second diffractive optical element and a second refractive optical element, the second corrective optics block configured to correct fixed pattern noise in the projected image light.
12. A virtual reality headset comprising:
a first optical block with one end adjacent to a first exit pupil corresponding to a position of a user's first eye when using the virtual reality headset, the optical block comprising:
a first electronic display element opposite the first exit pupil, the first electronic display element projecting image light toward the first exit pupil; and
a first corrective optics block between the first electronic display element and the first exit pupil, the first corrective optics block comprising a first diffractive optical element and configured to correct one or more types of optical error in the projected image light; and
a second optical block with one end adjacent to a second exit pupil corresponding to a position of the user's second eye when using the virtual reality headset, the second optical block separate from the first optical block and comprising:
a second electronic display element opposite the second exit pupil, the second electronic display element projecting image light toward the second exit pupil; and
a second corrective optics block between the second electronic display element and the second exit pupil, the second corrective optics block comprising a second diffractive optical element and configured to correct the one or more types of optical error in the projected image light.
13. The virtual reality headset of claim 12 , wherein the first and second diffractive optical elements are Fresnel lenses.
14. The virtual reality headset of claim 12 , wherein each of the first and second diffractive optical elements has a higher density of grooves near its center.
15. The virtual reality headset of claim 12 , wherein each of the first and second corrective optics blocks further comprise a refractive optical element.
16. The virtual reality headset of claim 15 , wherein the refractive optical element is a convex lens.
17. The virtual reality headset of claim 15 , wherein each of the first and second diffractive optical elements is secured to the corresponding refractive optical element via molded pins.
18. The virtual reality headset of claim 12 , wherein the one or more types of optical error comprise fixed pattern noise.
19. The virtual reality headset of claim 18 , wherein each of the first and second corrective optics block are configured to slightly blur image light projected from sub-pixels of the corresponding electronic display element.
20. The virtual reality headset of claim 12 , wherein for each of the first and second corrective optics blocks, an effective focal length of the corrective optics block is larger than a distance from the corrective optics block to the corresponding electronic display element.