Optical system with nanoscale projection antireflection layer/embossing

• US 7,529,026 B2
• Filed: 04/28/2005
• Issued: 05/05/2009
• Est. Priority Date: 04/28/2005
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Gardner, Daniel C., Piehl, Arthur R.
• Primary Examiner(s): Mack; Ricky L
• Assistant Examiner(s): Dinh; Jack
• Application Number:
  US11/116,333
• Publication Number:
  US 20060245062A1
• Time in Patent Office: 1,468 Days
• Field of Search: 359/619, 359290-292, 359/298, 359/247, 359/260, 359/261, 359/263, 359/315, 359/317, 359/318, 359/627, 359/566, 359/569
• US Class Current: 359/619
• CPC Class Codes: G02B 1/11 Anti-reflection coatings
• CPC Class Codes: G02B 1/118 having sub-optical wavelength surface structures designed to provide an enhanced transmittance, e.g. moth-eye structures
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02F 2203/12 spatial light modulator

Abstract

An optical system having a radiation transparent member and an anti-reflective embossment embossed into at least one surface of the transparent member. The embossment has spaced structures configured to permit incident radiation to pass through the embossment and the radiation transparent member, and to, at least, attenuate reflection of the incident radiation off the embossment. The structures are maximally spaced from one another by a subwavelength of the incident radiation.

Claims

1. An optical system having a radiation transparent member, comprising:

a light source that produces a beam of light;

a device for selectively modifying the beam of light, the device including the radiation transparent member and a reflective member which are arranged to be movable with respect to one another; and

an anti-reflective embossment embossed into at least one surface of the radiation transparent member, the embossment comprising spaced structures configured to permit incident radiation to pass through the embossment and the radiation transparent member, and to, at least, attenuate reflection of the incident radiation off the embossment, the structures being maximally spaced from one another by a subwavelength of the incident radiation.

2. An optical system as set forth in claim 1, wherein the beam of light is white light and wherein the light source produces the white light.

3. An optical system as set forth in claim 2, wherein the device comprises a spatial light modulator device.

4. An optical system as set forth in claim 3, wherein the spatial light modulator device comprises at least one of a DMMD, a LCoS and an interferometer type reflection device.

5. An optical system as set forth in claim 2, wherein the device is enclosed in a package comprising at least one transparent element.

6. An optical system as set forth in claim 5, wherein the at least one transparent element comprises a sheet of glass.

7. An optical system as set forth in claim 5, wherein at least one side of the transparent element is embossed with the anti-reflective embossment.

8. An optical system as set forth in claim 1, wherein the distance between the radiation transparent member and the reflective member is selectively controlled so that light, which enters a gap between the radiation transparent member and the reflective member, is reflected between the radiation transparent member and the reflective member to induce constructive and/or destructive interference and to result in the modified beam of light.

9. An optical system as set forth in claim 8, wherein the radiation transparent member has a surface, which is outboard with respect to the reflective member, embossed with the embossment.

10. An optical system as set forth in claim 8, wherein the selective control is implemented using electrostatic actuation.

11. An optical system as set forth in claim 10, further comprising a retarder optical component for rotating an angle of polarization of light which is polarized by reflection in the beam splitting prism.

12. An optical system as set forth in claim 11, wherein the retarder layer comprises the light transmitting member.

13. An optical system as set forth in claim 2, wherein the optical system further comprises a beam splitting prism arranged to receive the beam of light from the light source and to reflect the beam of light in a first direction into the device and wherein the modified beam of light is directed out through the beam splitting prism.

14. An optical system as set forth in claim 1, wherein the structures are projections having radiation subwavelength dimensions.

15. An optical system as set forth in claim 14, wherein the projections are about 3-4 times higher than their base width.

16. An optical system as set forth in claim 14, wherein the projections have bases which are located proximate and/or merge with those of adjacent projections in a manner which attenuates low angle surfaces which can reflect light back away from the light transmitting member.

17. An optical system as set forth in claim 14, wherein the projections are one of essentially conical or frusto-conical in configuration.

18. An optical system as set forth in claim 1, wherein the projections are formed so that a low angle surface between the projections and which can reflect incident radiation is essentially absent.

19. An embossed anti-reflection surface in an image projection arrangement comprising:

a plurality of projections formed in a surface of a radiation transparent member through which radiation, having a wavelength range, passes to an image formation device, peaks of the projections being separated by distances which are less than any wavelength in a wavelength range of radiation;

wherein the image formation device comprises a matrix of elements which modify the incident radiation;

wherein the matrix of elements each comprise the radiation transparent member and a radiation reflective member which are arranged to be movable with respect one another.

20. An embossed anti-reflection surface as set forth in claim 19, wherein the radiation has a wavelength or wavelength range which falls within a range of white light.

21. An embossed anti-reflection surface as set forth in claim 20, wherein a gap formed between the radiation transparent member and the radiation reflective member can be selectively controlled to induce radiation passing through the radiation transparent member to be reflected in a manner which induces constructive or destructive interference and modify radiation which is emitted back through the transparent member.

22. An embossed anti reflection surface in an image projection arrangement comprising:

a plurality of nano-scale projections formed in a surface of a transparent member which forms part of each of a matrix of light modifying elements that form an image formation device;

wherein the matrix of light modifying elements modify the incident radiation;

wherein the matrix of light modifying elements each comprise a radiation transparent member and a radiation reflective member which are arranged to be movable with respect one another.

23. An image formation device, comprising:

means for transmitting light, the means for transmitting having a surface;

means for attenuating reflection from the surface using essentially conical/frustoconical-shaped nanostructures which have peaks that are spaced by a distance less than any wavelength in a wavelength range of white light;

means for reflecting light, the means for reflecting light having a radiation transparent member and a reflective member which are arranged to be movable with respect one another.

24. An image formation device, comprising:

a plurality of transparent members arranged in a predetermined spatial relationship; and

an anti-reflective embossment formed in a surface of at least two of the plurality of transparent members, the anti-reflective embossment comprising essentially conical/frustoconical-shaped nanostructures which have peaks that are spaced by a distance less than a wavelength in a wavelength range of visible white light;

wherein at least one of the plurality of transparent members and a reflective member are arranged to be movable with respect to one another.