Head-wearable displays with a tiled field of view using a single microdisplay

• US 9,964,769 B2
• Filed: 06/10/2016
• Issued: 05/08/2018
• Est. Priority Date: 06/10/2016
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google LLC (Alphabet Inc.)
• Inventors: Martinez, Oscar A., Cakmakci, Ozan, Dunphy, James C.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US15/179,198
• Publication Number:
  US 20170357090A1
• Time in Patent Office: 697 Days
• Field of Search: 359246, 359619, 359629-631, 345 7, 345 8, 345204, 345207, 348115, 385 31, 385 33
• CPC Class Codes: G02B 2027/0112 comprising device for genereting colour display
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/013 comprising a combiner of particular shape, e.g. curvature
• CPC Class Codes: G02B 25/001 Eyepieces
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/1066 for enhancing image performance, like resolution, pixel numbers, dual magnifications or dynamic range, by tiling, slicing or overlapping fields of view
• 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 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0026 Wavelength selective element, sheet or layer, e.g. filter or grating
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02F 1/0136 for the control of polarisation, e.g. state of polarisation [SOP] control, polarisation scrambling, TE-TM mode conversion or separation G02F1/0353 takes precedence

Abstract

Implementations are described of an eyepiece for a head wearable display. The eyepiece includes a curved lightguide for guiding display light via total internal reflection between a peripherally-located input surface and a viewing region and an output coupler disposed across the viewing region to redirect the display light towards an eyeward direction for output from the curved light guide. The output coupler has an optical axis and has a set of reflective surfaces that includes at least two individual reflective surfaces to reflect incident display light toward the eyeward direction in at least two different directions relative to the optical axis of the output coupler. Other embodiments are disclosed and claimed.

Claims

1. An eyepiece for a head-wearable display, the eyepiece comprising:

a curved light guide for guiding display light via total internal reflection between a peripherally-located input surface and a viewing region; and

an output coupler disposed across the viewing region to redirect the display light towards an eyeward direction for output from the curved light guide, the output coupler having an optical axis and comprising a set of reflective surfaces that includes at least two individual reflective surfaces to reflect incident display light toward the eyeward direction in at least two different directions relative to the optical axis of the output coupler.

2. The eyepiece of claim 1, wherein at least one of the individual reflective surfaces has positive or negative optical power.

3. The eyepiece of claim 1, wherein the set of reflective surfaces includes more than two individual reflective surfaces and includes at least one subset of two or more individual reflective surfaces that reflect incident display light in the same direction relative to the optical axis.

4. The eyepiece of claim 1, wherein the set of reflective surfaces includes more than two individual reflective surfaces each individual reflective surface reflects incident display light in a different direction relative to the optical axis than any other individual reflective surface in the set.

5. The eyepiece of claim 1, wherein the set of reflective surfaces includes a subset of individual reflective surfaces having a polarizing film on them that passes display light having a first polarization state and a subset of individual reflective surfaces having a polarizing film on them that passes display light having a second polarization state.

6. The eyepiece of claim 1, wherein the set of reflective surfaces includes a polarization-dependent dielectric thin film coating on them, so that a subset of individual reflective surfaces reflects display light having a first polarization state and another subset of individual reflective surfaces reflects display light having a second polarization state.

7. The eyepiece of claim 1, wherein the set of reflective surfaces includes a subset of individual reflective surfaces having a color filter on them that passes display light having a first color, a subset of individual reflective surfaces having a color filter on them that passes display light having a second color, and a subset of individual reflective surfaces having a color filter on them that passes display light having a third color.

8. The eyepiece of claim 1, wherein the set of reflective surfaces include a wavelength-selective dielectric thin film coating on them such that a first subset of individual reflective surfaces reflects display light having a first color, a second subset of individual reflective surfaces reflects display light having a second color, and a third subset of individual reflective surfaces reflects display light having a third color.

9. The eyepiece of claim 1, wherein the set of reflective surfaces includes a subset of individual reflective surfaces having a color filter on them that passes display light having a first color and a subset of individual reflective surfaces having a color filter on them that passes display light having second and third colors.

10. The eyepiece of claim 1, wherein the set of reflective surfaces include a wavelength-selective dielectric thin film coating on them such that a subset of individual reflective surfaces reflects display light having a first color and another subset of individual reflective surfaces reflects display light having second and third colors.

11. The eyepiece of claim 1, wherein the set of reflective surfaces includes a subset of individual reflective surfaces that reflect a first portion of the display light and a subset of individual reflective surfaces that reflects a second portion of the display light.

12. The eyepiece of claim 1, wherein each individual reflective surface in the set of reflective surfaces is a switchable mirror that can be switched between a reflective state and a non-reflective state.

13. A head-wearable display comprising:

a display source to generate display light;

an eyepiece to guide the display light to a viewing region, the eyepiece comprising;

a curved light guide for guiding display light via total internal reflection between a peripherally-located input surface and the viewing region,

an output coupler disposed across the viewing region to redirect the display light towards an eyeward direction for output from the curved light guide, the output coupler having an optical axis and comprising a set of reflective surfaces that includes at least two individual reflective surfaces to reflect incident display light toward the eyeward direction in at least two different directions relative to the optical axis of the output coupler; and

a frame assembly to support the eyepiece for wearing on a head of a user with the viewing region positioned in front of an eye of the user.

14. The head-wearable display of claim 13, wherein at least one of the individual reflective surfaces has positive or negative optical power.

15. The head-wearable display of claim 13, wherein the set of reflective surfaces includes more than two individual reflective surfaces and includes at least one subset of two or more individual reflective surfaces that reflect incident display light in the same direction relative to the optical axis.

16. The head-wearable display of claim 13, wherein the set of reflective surfaces includes more than two individual reflective surfaces each individual reflective surface reflects incident display light in a different direction relative to the optical axis than any other individual reflective surface in the set.

17. The head-wearable display of claim 13, wherein the set of reflective surfaces includes a subset of individual reflective surfaces having a polarizing film on them that passes display light having a first polarization state and a subset of individual reflective surfaces having a polarizing film on them that passes display light having a second polarization state.

18. The head-wearable display of claim 17, further comprising a polarizer optically coupled to the display source to polarize the display light, wherein the polarizer comprises an array of polarizers including rows and columns of polarizing cells, wherein the polarizing cells alternate row-wise and column-wise between the first polarization state and the second polarization state.

19. The head-wearable display of claim 17, further comprising a polarizer optically coupled to the display source to polarize the display light, wherein the polarizer comprises:

a switchable polarizer whose entire area can be switched between the first polarization state and the second polarization state at a selected frequency; and

a circuit coupled to the switchable polarizer to switch the polarization between the first polarization state and the second polarization state at the selected frequency.

20. The head-wearable display of claim 13, wherein the set of reflective surfaces includes a polarization-dependent dielectric thin film coating on them so that a subset of individual reflective surfaces reflects display light having a first polarization state and another subset of individual reflective surfaces reflects display light having a second polarization state.

21. The head-wearable display of claim 13, further comprising a color filter array optically coupled to the display source, wherein the color filter array includes individual color filters of the first color, individual color filters of the second color, and individual color filters of the third color.

22. The head-wearable display of claim 21, wherein the set of reflective surfaces includes a subset of individual reflective surfaces having a color filter on them that passes display light having a first color, a subset of individual reflective surfaces having a color filter on them that passes display light having a second color, and a subset of individual reflective surfaces having a color filter on them that passes display light having a third color.

23. The head-wearable display of claim 21, wherein the set of reflective surfaces include a wavelength-selective dielectric thin film coating on them such that a first subset of individual reflective surfaces reflects display light having a first color, a second subset of individual reflective surfaces reflects display light having a second color, and a third subset of individual reflective surfaces reflects display light having a third color.

24. The head-wearable display of claim 21, wherein the set of reflective surfaces includes a subset of individual reflective surfaces having a color filter on them that passes display light having a first color and a subset of individual reflective surfaces having a color filter on them that passes display light having second and third colors.

25. The head-wearable display of claim 21, wherein the set of reflective surfaces include a wavelength-selective dielectric thin film coating on them such that a subset of individual reflective surfaces reflects display light having a first color and another subset of individual reflective surfaces reflects display light having second and third colors.

26. The head-wearable display of claim 13, wherein the set of reflective surfaces includes a first subset of reflective surfaces that reflect a first portion of the display light and a second subset of reflective surfaces that reflects a second portion of the display light.

27. The head-wearable display of claim 26, further comprising a plurality of lenses optically coupled to the display source wherein some of the plurality of lenses direct the first portion of the display light to the first subset of reflective surfaces and wherein the remainder of the plurality of lenses direct the second portion of the display light to the second subset of reflective surfaces.

28. The head-wearable display of claim 13, wherein each individual reflective surface in the set of reflective surfaces is a switchable mirror that can be switched between a reflective state and a non-reflective state.

29. The head-wearable display of claim 28, further comprising a circuit coupled to the switchable mirrors to switch the reflective state of each switchable mirror between a reflective state and a non-reflective state at a selected frequency.

30. The head-wearable display of claim 29, wherein the selected mirror-switching frequency is synchronized with the display so that an image reflected by each reflective surface is unique.