Polarizing beam splitter with low light leakage

• US 10,302,957 B2
• Filed: 02/24/2017
• Issued: 05/28/2019
• Est. Priority Date: 02/24/2016
• Status: Active Grant

• Current Assignee: Magic Leap, Inc.
• Original Assignee: Magic Leap, Inc.
• Inventors: Sissom, Bradley Jay
• Primary Examiner(s): Font, Frank G
• Application Number:
  US15/442,461
• Publication Number:
  US 20170242264A1
• Time in Patent Office: 823 Days
• Field of Search: 35948504, 35948506, 385 31, 385131
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area
• CPC Class Codes: H04N 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28

Abstract

In some embodiments, a polarizing beam splitter is provided. The beam splitter may comprise an optically transmissive spacer having first and second opposing faces, with a first polarizer on the first opposing face and a second polarizer on the second opposing face. The optically transmissive spacer may separate first and second triangular prisms of a cube-type beam splitter, with the first polarizer between the first triangular prism and the first opposing face of the spacer, and the second polarizer between the second triangular prism and the second opposing face of the spacer.

Claims

1. A polarizing beam splitter comprising:

an optically transmissive spacer having first and second opposing faces, wherein the optically transmissive spacer comprises a first region along the first face and a second region along the second face;

a reflection-preventing polarizer between the first and second regions;

a first polarizer on the first opposing face; and

a second polarizer on the second opposing face,

wherein the first polarizer is a different type of polarizer from the second polarizer.

2. The polarizing beam splitter of claim 1, wherein the optically transmissive spacer is a plate.

3. The polarizing beam splitter of claim 2, wherein the plate is a curved plate.

4. The polarizing beam splitter of claim 1, wherein the optically transmissive spacer separates first and second triangular prisms,

wherein the first polarizer is between the first triangular prism and the first opposing face of the spacer,

wherein the second polarizer is between the second triangular prism and the second opposing face of the spacer.

5. The polarizing beam splitter of claim 1, wherein the first and second triangular prisms form a cube-type beam splitter.

6. The polarizing beam splitter of claim 1, wherein the reflection-preventing polarizer between the first and second regions of the optically transmissive spacer comprises an absorptive polarizer between the first and second opposing faces.

7. The polarizing beam splitter of claim 6, wherein the absorptive polarizer extends parallel to the first and second opposing faces.

8. The polarizing beam splitter of claim 1, wherein the first polarizer and the second polarizer are configured to transmit light of a same polarization.

9. The polarizing beam splitter of claim 1, wherein the first polarizer is a polarizer selected from the group consisting of wire grid polarizers, thin film polarizers, and multilayer birefringent stack polarizers.

10. The polarizing beam splitter of claim 9, wherein the second polarizer is a polarizer selected from the group consisting of wire grid polarizers, thin film polarizers, and multilayer birefringent stack polarizers.

11. The polarizing beam splitter of claim 1, wherein the optically transmissive spacer comprises one or more of a glass or a polymer.

12. A display system comprising:

a polarizing beam splitter comprising;

an optically transmissive spacer having first and second opposing faces, wherein the optically transmissive spacer comprises a first region along the first face and a second region along the second face;

a reflection-preventing polarizer between the first and second regions;

a first polarizer on the first opposing face; and

a second polarizer on the second opposing face;

a light source;

a reflective spatial light modulator configured to reflect incident light from the polarizing beam splitter back to the polarizing beam splitter; and

a reflector,

wherein the polarizing beam splitter is configured to;

reflect light from the light source towards the reflector;

transmit light from the reflector to the spatial light modulator; and

reflect light from the spatial light modulator such that the light propagates away from the polarizing beam splitter and the light source.

13. The display system of claim 12, wherein the reflector and the spatial light modulator are on opposite sides of the polarizing beam splitter, and wherein the light source is positioned to output light to the polarizing beam splitter in a direction orthogonal to an optical path extending from the reflector to the spatial light modulator.

14. The display system of claim 13, further comprising a refractive optic configured to receive the light propagating away from the polarizing beam splitter and the light source, and to transmit the light towards a viewer.

15. The display system of claim 13, further comprising a waveguide comprising:

incoupling optical elements; and

outcoupling optical elements,

wherein the incoupling optical elements are configured to receive and incouple the light propagating away from the beam splitter and the light source,

wherein the out coupling optical elements are configured to outcouple the incoupled light towards a viewer.

16. The display system of claim 15, further comprising a stack of the waveguides.

17. The display system of claim 16, wherein each waveguide of the stack is configured to output light with different amounts of divergence in comparison to one or more other waveguides of the stack of waveguides.

18. The display system of claim 12, wherein the optically transmissive spacer is a plate.

19. The display system of claim 12, wherein the optically transmissive spacer separates first and second triangular prisms,

wherein the first polarizer is between the first triangular prism and the first opposing face of the spacer,

wherein the second polarizer is between the second triangular prism and the second opposing face of the spacer.

20. The display system of claim 12, wherein the reflection-preventing polarizer between the first and second regions of the optically transmissive spacer comprises an absorptive polarizer between the first and second opposing faces.