Anti-moiré pattern diffuser for optical systems

• US 9,927,560 B2
• Filed: 10/22/2015
• Issued: 03/27/2018
• Est. Priority Date: 10/22/2014
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Intel Corporation
• Inventors: Masson, Jonathan, Le Gros, Christophe, Kilcher, Lucio
• Primary Examiner(s): Phan, James
• Application Number:
  US14/920,437
• Publication Number:
  US 20160116647A1
• Time in Patent Office: 887 Days
• Field of Search: 35948601-48603, 359599, 359250-253, 359298, 359301, 359303, 359316, 359465, 3592079
• CPC Class Codes: G02B 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence
• CPC Class Codes: G02B 27/286 for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G02B 27/60 Systems using moiré fringes
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 5/0294 adapted to provide an additional optical effect, e.g. anti-reflection or filter
• CPC Class Codes: G02B 5/3058 comprising electrically conductive elements, e.g. wire grids, conductive particles
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G03B 21/2073 Polarisers in the lamp house peculiar to electronic spatial light modulators H04N9/3197
• CPC Class Codes: G03B 21/208 Homogenising, shaping of the illumination light

Abstract

Disclosed herein are devices and techniques related to optical diffusers and particularly, diffusers to reduce moiré patterns in a projected image. The device may comprise an array of micro-focal elements or reflectors and a light polarization grid. The light polarization grid configured to change a polarization between portions of a light beam and the micro-focal elements of reflectors to diffuse the light beam such that portions of the light beam having a difference in polarization may meet at a point.

Claims

1. A system comprising:

an optical diffuser; and

a scanning mirror system to receive a light beam and to scan the light beam across the optical diffuser, the optical diffuser comprising;

a light polarization grid to receive a light beam and to change a polarization a portion of the light beam; and

an array of micro-focal elements optically coupled to the light polarization grid to diffuse the light beam.

2. The system of claim 1, the scanning mirror system comprising a mirror to rotate about at least one axis to scan the light beam across the optical diffuser.

3. The system of claim 1, the light polarization grid comprising a plurality of cells, a first group of the plurality of cells to change a polarization of at least a first wave of the light beam and a second group of the plurality of cells to transmit at least a second wave of the light beam having a substantially original polarization.

4. The system of claim 3, the array of micro-focal elements to diffuse the first and second wave to meet at a point, wherein polarization of the first wave and the polarization of the second wave are substantially non-interfering at the point.

5. The system of claim 1, wherein the array of micro-focal elements is disposed between the scanning mirror system and the light polarization grid.

6. The system of claim 1, wherein the light polarization grid is disposed between the scanning mirror system and the array of micro-focal elements.

7. A system comprising:

a scanning mirror system to receive a light beam and to scan the light beam across a light polarization grid;

the light polarization grid to receive a plurality of waves of the light beam, each of the plurality of waves to have an initial polarization, the light polarization grid comprising a plurality of cells, a first group of the plurality of cells to change the initial polarization of at least a first one of the plurality of waves, a second group of the plurality of cells to transmit at least a second one of the plurality of waves with the initial polarization; and

an array of micro-focal elements optically coupled to the light polarization grid to diffuse the light beam.

8. The system of claim 7, the array of micro-focal elements to diffuse the first one and the second one of the plurality of waves to meet at a point, wherein polarization of the first wave and the polarization of the second wave are substantially non-interfering at the point.

9. The system of claim 8, wherein the initial polarization is linear, the first group of the plurality of cells to change the initial polarization of at least the first one of the plurality of waves to be orthogonal to the initial polarization.

10. The system of claim 8, wherein the initial polarization is circular, the first group of the plurality of cells to change the handedness of the polarization of at least the first one of the plurality of waves.