WHOLE IMAGE SCANNING MIRROR DISPLAY SYSTEM

• US 20130016413A1
• Filed: 07/12/2011
• Published: 01/17/2013
• Est. Priority Date: 07/12/2011
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Miao, Xiaoyu, Amirparviz, Babak, Saeedi, Ehsan
• Granted Patent: US 8,817,379 B2
• Time in Patent Office: Days
• US Class Current: 359/205.1
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 27/0093 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/0172 characterised by optical features

Abstract

An optical apparatus includes an image source, a scanning mirror, an actuator, and a scanning controller. The image source outputs an image by simultaneously projecting a two-dimensional array of image pixels representing a whole portion of the image. The scanning mirror is positioned in an optical path of the image to reflect the image. The actuator is coupled to the scanning mirror to selectively adjust the scanning mirror about at least one axis. The scanning controller is coupled to the actuator to control a position of the scanning mirror about the at least one axis. The scanning controller includes logic to continuously and repetitiously adjust the position of the scanning mirror to cause the image to be scanned over an eyebox area that is larger than the whole portion of the image.

Claims

1. An image display apparatus, comprising:

an image source to output an image by simultaneously projecting a two-dimensional array of image pixels representing a whole portion of the image;

a scanning mirror positioned in an optical path of the image output from the image source to reflect the image;

an actuator coupled to the scanning mirror to selectively adjust the scanning mirror about at least one axis; and

a scanning controller coupled to the actuator to control a position of the scanning mirror about the at least one axis, wherein the scanning controller includes logic to repetitiously adjust the position of the scanning mirror to cause the image to be scanned over an eyebox area that is larger than the whole portion of the image.

2. The image display apparatus of claim 1, wherein the logic of the scanning controller is coupled to the actuator to scan the whole portion of the image horizontally to enlarge a horizontal dimension of the eyebox area from which the image may be viewed.

3. The image display apparatus of claim 2, wherein the actuator is coupled to selectively adjust the scanning mirror about two axes, wherein the logic of the scanning controller is further coupled to the actuator to scan the whole portion of the image both horizontally and vertically to enlarge the horizontal dimension and a vertical dimension of the eyebox area from which the image may be viewed.

4. The image display apparatus of claim 1, wherein the actuator comprises a micro-electro-mechanical system (“

MEMS”

) scanner and the scanning mirror comprises a reflective surface disposed on the MEMS scanner.

5. The image display apparatus of claim 4, further comprising:

a diffractive lens disposed over the reflective surface on the MEMS scanner, the diffractive lens configured to increase a divergence of light rays of the image to spread the image.

6. The image display apparatus of claim 1, wherein the optical apparatus comprises a head mounted display that when worn by a user positions the image source and the scanning mirror in peripheral locations to an eye of the user, the optical apparatus further comprising:

a light bending optics positioned in the optical path between the scanning mirror and the eye of the user to transport the image to be in front of the eye.

7. The image display apparatus of claim 6, further comprising:

a intermediate mirror positioned in the optical path between the image source and the scanning mirror and orientated obliquely to an emission aperture of the image source to redirect the image projected from the image source onto the scanning mirror, wherein the image source and the intermediate mirror are positioned in a temple region of the head mounted display while the scanning mirror and actuator are positioned at a forward eyeglass corner of the head mounted display.

8. The image display apparatus of claim 6, further comprising:

a gaze tracking camera optically aligned to capture real-time eye images of the eye when the optical apparatus is worn by the user; and

a gaze tracking controller coupled to receive the eye images from the gaze tracking camera, coupled to analyze the eye images to determine a gazing direction, and coupled to the scanning controller to provide a feedback control signal to the scanning controller to dynamically adjust a bias position of the actuator based upon the gazing direction of the eye.

9. The image display apparatus of claim 8, wherein a location of the eyebox within which the image is scanned is selected based upon the bias position determined based upon the gazing direction of the eye.

10. A head mounted display (“

HMD”

) for displaying an image to a user, the head mounted display comprising;

a near-to-eye optical system including;

an image source to output the image by simultaneously projecting a two-dimensional array of image pixels representing a whole portion of the image;

a scanning mirror positioned in an optical path of the image output from the image source to reflect the image;

an actuator coupled to the scanning mirror to selectively adjust the scanning mirror about at least one axis; and

a scanning controller coupled to the actuator to control a position of the scanning mirror about the at least one axis, wherein the scanning controller includes logic to continuously and repetitiously adjust the position of the scanning mirror to cause the image to be scanned over an eyebox area that is larger than the whole portion of the image; and

a frame assembly to support the near-to-eye optical system for wearing on a head of the user.

11. The HMD of claim 10, wherein the actuator comprises a micro-electro-mechanical system (“

MEMS”

) scanner and the scanning mirror comprises a reflective surface disposed on the MEMS scanner.

12. The HMD of claim 11, wherein the near-to-eye optical system further comprises:

a diffractive lens disposed over the reflective surface on the MEMS scanner, the diffractive lens configured to increase a divergence of light rays of the image to spread the image.

13. The HMD of claim 10, wherein the frame assembly mounts the image source and the scanning mirror in peripheral locations to an eye of the user, the HMD further comprising:

a light bending optics positioned in the optical path between the scanning mirror and the eye of the user to transport the image to be in front of the eye.

14. The optical apparatus of claim 13, wherein the near-to-eye optical system further comprises:

a intermediate mirror positioned in the optical path between the image source and the scanning mirror and orientated obliquely to an emission aperture of the image source to redirect the image projected from the image source onto the scanning mirror, wherein the image source and the intermediate mirror are mounted to the frame assembly in a temple region of the HMD while the scanning mirror and actuator are mounted at a forward eyeglass corner of the HMD.

15. The HMD of claim 10, further comprising:

a gaze tracking camera optically aligned to capture real-time eye images of the eye when the HMD is worn by the user; and

a gaze tracking controller coupled to receive the eye images from the gaze tracking camera, coupled to analyze the eye images to determine a gazing direction, and coupled to the scanning controller to provide a feedback control signal to the scanning controller to dynamically adjust a bias position of the actuator based upon the gazing direction of the eye.

16. A method of displaying an image with a head mounted display, the method comprising:

simultaneously projecting a two-dimensional array of image pixels representing a whole portion of the image from an image source, the image source positioned at a peripheral location to an eye of a user;

transporting the image from the peripheral location to be in front of the eye with a light optics apparatus;

contemporaneously reflecting the whole portion of the image with a mirror positioned within an optical path of the image;

repetitiously actuating the mirror to redirect the image along different optical paths; and

scanning the whole portion of the image over an eyebox area that is larger than the whole portion of the image as a consequence of actuating the mirror.

17. The method of claim 16, wherein scanning the whole portion of the image over the eyebox area comprises scanning the whole portion of the image horizontally across the eye of the user to enlarge a horizontal dimension of the eyebox area.

18. The method of claim 17, wherein scanning the whole portion of the image over the eyebox area comprises scanning the whole portion of the image both horizontally and vertically across the eye of the user to enlarge the horizontal dimension and a vertical dimension of the eyebox area, wherein the mirror is actuated in at least two dimensions.

19. The method of claim 16, further comprising:

diffracting the image to increase the a divergence of the image and increase the eyebox area from which the image may be viewed, wherein the diffracting is executed by a diffraction grating disposed on a surface of the mirror.

20. The method of claim 16, further comprising:

capturing a gazing image of the user eye while displaying the image to the eye;

analyzing the gazing image to determine a gazing direction in real-time while displaying the image to the eye; and

adjusting a bias position of the mirror through which the repetitious actuating oscillates in response to the determined gazing direction to track eye movement with the image.