Apparatus and method for display lighting adjustment

• US 8,970,571 B1
• Filed: 03/13/2012
• Issued: 03/03/2015
• Est. Priority Date: 03/13/2012
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Wong, Adrian, Mirov, Russell N.
• Primary Examiner(s): Giesy, Adam R
• Assistant Examiner(s): HEYI, HENOK G
• Application Number:
  US13/419,299
• Time in Patent Office: 1,085 Days
• Field of Search: None
• US Class Current: 345/207
• CPC Class Codes: G02B 2027/0112 comprising device for genereting colour display
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/014 comprising information/image processing systems
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 2027/0194 with combiner of laminated type, for optical or mechanical aspects
• 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: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources

Abstract

An apparatus includes a light source, a display array, a light relay, a photodetector, control circuitry, and measurement circuitry. The light source is for providing lamp light during an ON-time of the light source. The display array is positioned to receive and selectively manipulate the lamp light. The light relay is positioned to receive the image light from the display array. The photodetector is optically coupled to receive light. Control circuitry is coupled to the light source for cycling the light source and coupled to the measurement circuitry for coordinating light measurements of the photodetector.

Claims

1. A method of color balancing an illumination source of a display array, the method comprising:

sequentially providing first, second, and third color lamp light to the display array, wherein only one of the first, second, and third color lamp light is sequentially provided to the display array at one time;

acquiring a first light measurement of the first color lamp light, while the first color lamp light is provided to the display array;

acquiring a second light measurement of the second color lamp light, while the second color lamp light is provided to the display array;

acquiring a third light measurement of the third color lamp light, while the third color lamp light is provided to the display array;

acquiring a fourth light measurement of ambient light, wherein the fourth light measurement is made while the first, second, and third color lamp light are not provided to the display array, and wherein the first, second, third, and fourth light measurement are measured by one photodetector;

determining an emission-time for each of the first, second, and third color lamp light, based on the first, second, third, and fourth light measurements, respectively; and

sequentially re-providing the first, second, and third color lamp light to the display array according to the emission-time determined for each of the first, second, and third color lamp light.

2. The method of claim 1, wherein the ambient light is head mounted display (“

HMD”

) ambient light that was directed into a light relay of the HMD by a beam splitter, wherein the light relay is optically coupled to receive color sequential images from the display array and deliver the color sequential images to a viewing end of the light relay for presenting to an eye of a user, when the HMD is worn.

3. The method of claim 1, wherein the determining the emission-time for the each of the first, second, and third color lamp light further based on the fourth light measurement produces a scale factor to be applied to the emission-time for the each of the first, second, and third color lamp light.

4. The method of claim 1, wherein determining the emission-time for the each of the first, second, and third color lamp light is further based on a previous first, second, and third light measurement of previous provided first, second, and third color lamp light, respectively.

5. The method of claim 1, wherein determining the emission-time for the first, second, and third color lamp light color balances a light source to a pre-determined white point.

6. The method of claim 1, wherein sequentially providing the first, second, and third color lamp light to the display array occurs at a frequency sufficiently high enough to avoid having an eye of a viewer of the display array perceive flicker.

7. At least one non-transitory machine-accessible storage medium having instructions stored therein that, when executed by a head mounted display (“

HMD”

), will cause the HMD to perform operations comprising;

sequentially providing first, second, and third color lamp light to a display array of the HMD, wherein only one of the first, second, and third color lamp light is sequentially provided to the display array at one time;

acquiring a first light measurement of the first color lamp light, while the first color lamp light is provided to the display array;

acquiring a second light measurement of the second color lamp light, while the second color lamp light is provided to the display array;

acquiring a third light measurement of the third color lamp light, while the third color lamp light is provided to the display array;

acquiring a fourth light measurement of HMD ambient light that has been directed into a light relay optically coupled to receive color sequential images from the display array, wherein the fourth light measurement is made while the first, second, and third color lamp light are not provided to the display array, the first, second, third, and fourth light measurement measured by one photodetector;

determining an emission-time for each of the first, second, and third color lamp light, based on the first, second, third, and fourth light measurements, respectively; and

sequentially re-providing the first, second, and third color lamp light to the display array according to the emission-time determined for the each of the first, second, and third color lamp light.

8. The at least one non-transitory machine-accessible storage medium of claim 7, wherein the determining the emission-time for the each of the first, second, and third color lamp light further based on the fourth light measurement produces a scale factor to be applied to the emission-time for the each of the first, second, and third color lamp light.

9. The at least one non-transitory machine-accessible storage medium of claim 7, wherein the HMD ambient light is directed into the light relay by a beam splitter.

10. The at least one non-transitory machine-accessible storage medium of claim 7, wherein determining the emission-time for the each of the first, second, and third color lamp light is further based on a previous first, second, and third light measurement of previous provided first, second, and third color lamp light, respectively.

11. The at least one non-transitory machine-accessible storage medium of claim 7, wherein sequentially providing the first, second, and third color lamp light to the display array occurs at a frequency greater than 60 Hz.

12. A method of operating a head mounted display (“

HMD”

), the method comprising;

providing strobed lamp light from a light source to a display array of the HMD;

generating computer generated image (“

CGI”

) light along an optical path in a light relay when the light source is ON;

directing, with a beam splitter, the CGI light in an eyeward direction of the HMD when the light source is ON;

directing, with the beam splitter, HMD ambient light into the light relay;

acquiring, while the light source is OFF, an ambient light measurement of the HMD ambient light directed into the light relay by the beam splitter; and

adjusting an ON-time of the light source based on the ambient light measurement, to change a brightness level of the CGI light.

13. The method of claim 12, wherein adjusting the ON-time of the light source is further based on a previous ambient light measurement that was prior to the ambient light measurement.

14. The method of claim 12, wherein the light source includes a red, green, and blue light emitting diode (“

LED”

) and adjusting the ON-time of the light source includes adjusting, by a same scale factor, a red ON-time, a green ON-time, and a blue ON-time of the red, green, and blue LED, respectively.

15. The method of claim 12, wherein the beam splitter directs the HMD ambient light from an external scene side of the HMD that is opposite an eyeward side of the HMD.

16. At least one non-transitory machine-accessible storage medium having instructions stored therein that, when executed by a head mounted display (“

HMD”

), will cause the HMD to perform operations comprising;

providing strobed lamp light from a light source to a display array of the HMD;

generating computer generated image (“

CGI”

) light along an optical path in a light relay when the light source is ON;

directing, with a beam splitter, the CGI light in an eyeward direction of the HMD when the light source is ON;

directing, with the beam splitter, HMD ambient light into the light relay;

acquiring, while the light source is OFF, an ambient light measurement of the HMD ambient light directed into the light relay by the beam splitter; and

adjusting an ON-time of the light source based on the ambient light measurement, to change a brightness level of the CGI light.

17. The at least one non-transitory machine-accessible storage medium of claim 16, wherein adjusting the ON-time of the light source is further based on a previous ambient light measurement that was prior to the ambient light measurement.

18. The at least one non-transitory machine-accessible storage medium of claim 16, wherein the light source includes a red, green, and blue light emitting diode (“

LED”

) and adjusting the ON-time of the light source includes adjusting, by a same scale factor, a red ON-time, a green ON-time, and a blue ON-time of the red, green, and blue LED, respectively.

19. The at least one non-transitory machine-accessible storage medium of claim 16, wherein the beam splitter directs the ambient light from an external scene side of the HMD that is opposite an eyeward side of the HMD.