Composite variable light attenuator

Patent metadata

Field	Value
Publication number	US-9442293-B2
Application number	US-201414271139-A
Country	US
Kind code	B2
Filing date	May 6, 2014
Priority date	May 6, 2014
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

An optical stack includes a first variable element and a second variable element. The first variable element is configured to vary light transmission through the first variable element as a function of a first control signal. The second variable element is in series with the first variable element and is configured to vary light transmission through the second variable element as a function of a second control signal. A controller dynamically supplies the first control signal to the first variable element and supplies the second control signal to the second variable element.

First claim

The invention claimed is:

1. An optical stack assembly, comprising:
a first variable element having a discrete number of light transmission intervals and configured to vary light transmitted through the first variable element as a function of a first control signal;
a second variable element having a continuously tunable light transmission gradient in series with the first variable element and configured to vary light transmitted through the second variable element as a function of a second control signal, wherein a range of light transmission of the first variable element is greater than a range of light transmission of the second variable element; and
a controller to dynamically supply the first control signal to the first variable element and to supply the second control signal to the second variable element to achieve a greater range of light transmission than either the first variable element or the second variable element provide individually.

2. The optical stack of claim 1 , wherein the first control signal and the second control signal are electronically synchronized.

3. The optical stack of claim 1 , wherein the first variable element comprises a photonic crystal material.

4. The optical stack of claim 1 , wherein the second variable element comprises a liquid crystal material.

5. The optical stack of claim 1 , further comprising:
one or more static elements in series with the first and second variable elements and configured to vary light transmission through the optical stack.

6. The optical stack of claim 1 , further comprising:
one or more additional variable elements in series with the first and second variable elements.

7. The optical stack of claim 6 , further comprising:
one or more substrates in series with the first and second variable elements and configured to not vary light transmission through the optical stack.

8. A head-mounted display system, comprising:
a see-through display configured to display an image of a virtual object while transmitting ambient light from a surrounding environment;
an optical stack, including:
a first variable element having a discrete number of light transmission intervals and in series with the see-through display and configured to vary ambient light transmitted through the see-through display as a function of a first control signal; and
a second variable element in series with the see-through display and the first variable element and configured to vary ambient light transmitted through the see-through display as a function of a second control signal; and

a controller to dynamically supply the first control signal to the first variable element and to supply the second control signal to the second variable element to achieve a greater range of ambient light transmission through the see-through display than either the first variable element or the second variable element provides individually.

9. The head-mounted display system of claim 8 , further comprising:
an ambient light sensor; and
wherein the first and second control signals synchronously vary ambient light transmission through the first and second variable elements based on a level of ambient light detected by the ambient light sensor.

10. The head-mounted display system of claim 9 , wherein the first and second control signals synchronously vary ambient light transmission through the first and second variable elements based on a display application.

11. The head-mounted display system of claim 10 , wherein the first and second control signals synchronously vary ambient light transmission through the first and second variable elements based on a minimum power consumption required to achieve a desired ambient light transmission level.

12. The head-mounted display system of claim 9 , wherein the second variable element has a continuously tunable light transmission gradient.

13. The head-mounted display system of claim 12 , wherein the first variable element comprises a photonic crystal material, and the second variable element comprises a liquid crystal material.

14. A head-mounted display system, comprising:
a see-through display configured to display an image of a virtual object while transmitting ambient light from a surrounding environment;
an ambient light sensor;
an optical stack, including:
a clear plastic substrate;
a passive infra-red light blocking film in series with the see-through display;
a passive ultra-violet light blocking film in series with the see-through display;
a photonic crystal element configured to vary ambient light transmission through the see-through display at discrete light transmission intervals as a function of a first control signal based on an amount of ambient light detected by the ambient light sensor; and
a liquid crystal element configured to vary ambient light transmission through the see-through display over a continuous light transmission gradient as a function of a second control signal based on the amount of ambient light detected by the ambient light sensor; and

a controller to dynamically supply the first control signal to the photonic crystal element and to supply the second control signal to the liquid crystal element.

15. The head-mounted display system of claim 14 , wherein the photonic crystal element and the liquid crystal element cooperatively realize maximum light transmission when a control signal with a zero value is supplied.

16. The head-mounted display system of claim 15 , wherein the first control signal consumes more power than the second control signal when the first and second control signals each have non-zero values.

17. The head-mounted display system of claim 16 , wherein the controller is configured to:
dynamically supply a first control signal with a zero value if a commanded light transmission can be realized when the photonic crystal element has maximum light transmission.

Assignees

• Microsoft Technology Licensing Llc

Inventors

• Alton Daniel J
• Ackerman Nathan

Classifications

• G02C7/101

  having an electro-optical light valve (electro-optical elements per se G02F) · CPC title

• G02B2027/0178

  Eyeglass type (eyeglass details G02C) · CPC title

• G02B2027/0118

  comprising devices for improving the contrast of the display / brillance control visibility · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B27/017

  Head mounted · CPC title