Multifocal Display

• US 20160147078A1
• Filed: 03/09/2015
• Published: 05/26/2016
• Est. Priority Date: 11/25/2014
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Llull, Patrick, Wu, Wanmin, Bedard, Noah, Tosic, Ivana, Berkner, Kathrin
• Granted Patent: US 9,864,205 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02B 13/0095 Relay lenses or rod lenses in instruments for viewing the inside of hollow bodies G02B23/2446
• CPC Class Codes: G02B 13/22 Telecentric objectives or lens systems
• CPC Class Codes: G02B 25/001 Eyepieces
• CPC Class Codes: G02B 3/14 of variable focal length
• CPC Class Codes: G02B 30/52 the 3D volume being constructed from a stack or sequence of 2D planes, e.g. depth sampling systems
• CPC Class Codes: H04N 13/322 using varifocal lenses or mirrors
• CPC Class Codes: H04N 13/398 Synchronisation thereof; Control thereof

Abstract

A multifocal display for rendering a 3D scene as a series of 2D images. In one aspect, the multifocal display includes a display, an optical imaging system, a refractive focus actuator and a controller. The display renders the 2D images. The optical imaging system is image-side telecentric and creates an image of the display. The refractive focus actuator is positioned at the pupil of the optical imaging system. Thus, adjusting the refractive focus actuator alters a location of the image of the display but does not significantly alter a size of the image. The controller coordinates adjustment of the refractive focus actuator with rendering of the 2D images on the display. The waveform driving the focus actuator is preferably designed to reduce ringing and jitter effects.

Claims

1. A multifocal display for rendering a 3D scene as a series of 2D images, the multifocal display comprising:

a display, on which 2D images are rendered;

an optical imaging system positioned to create an image of the display, wherein the optical imaging system is image-side telecentric, the optical imaging system having a pupil;

a refractive focus actuator positioned at the pupil of the optical imaging system, wherein adjusting the refractive focus actuator alters a location of the image of the display but does not significantly alter a size of the image; and

a controller that coordinates adjustment of the refractive focus actuator with rendering of the 2D images on the display.

2. The multifocal display of claim 1 further comprising:

an eyepiece positioned to allow viewing the images of the display.

3. The multifocal display of claim 2 further comprising:

an optical combiner positioned to overlay the images of the display on a user'"'"'s natural view to implement an augmented reality.

4. The multifocal display of claim 2 further comprising:

a negative field lens located between the refractive focus actuator and the eyepiece.

5. The multifocal display of claim 2 wherein the multifocal display covers a field of view of at least 30 degrees.

6. The multifocal display of claim 1 wherein the refractive focus actuator is a deformable lens.

7. The multifocal display of claim 6 wherein the controller deforms the liquid lens such that the locations of the images are realized in a temporal order that is not monotonically ascending or descending.

8. The multifocal display of claim 6 wherein the controller deforms the liquid lens such that the locations of the images are realized in a temporal order that is monotonically ascending/descending for the odd image locations and then monotonically descending/ascending for the even image locations.

9. The multifocal display of claim 6 wherein the controller produces a drive signal to deform the liquid lens and the drive signal is a filtered version of a piece-wise flat signal.

10. The multifocal display of claim 6 wherein the controller produces a drive signal to deform the liquid lens and the drive signal optimizes an image quality metric of 3D scenes rendered on the multifocal display.

11. The multifocal display of claim 10 wherein the image quality metric accounts for image defocus.

12. The multifocal display of claim 10 wherein the image quality metric accounts for temporal quality.

13. The multifocal display of claim 6 wherein the controller produces a drive signal to deform the liquid lens and the drive signal optimizes an image error metric of an ideal rendering of 3D scenes versus the 3D scenes rendered on the multifocal display.

14. The multifocal display of claim 13 wherein the image error metric is a difference between locations of points in the ideal rendered 3D scenes versus locations of those points in the 3D scenes rendered on the multifocal display.

15. The multifocal display of claim 6 wherein the liquid lens can be adjusted over a range of five diopters.

16. The multifocal display of claim 1 further comprising:

an adjustable aperture within the optical imaging system, wherein the controller also coordinates adjustment of the aperture with adjustment of the refractive focus actuator.

17. The multifocal display of claim 1 wherein the optical imaging system is also object-side telecentric.

18. The multifocal display of claim 1 wherein the multifocal display can render 3D scenes at a rate of at least 60 scenes per second.

19. A method for rendering a 3D scene as a series of 2D images on a multifocal display comprising a display, an optical imaging system and a refractive focus actuator, the method comprising:

rendering on the display 2D images derived from the 3D scene, the optical imaging system creating an image of the display at a location;

adjusting the refractive focus actuator to alter the location of the image of the display, wherein adjusting the refractive focus actuator does not significantly alter a size of the image; and

coordinating adjustment of the refractive focus actuator with rendering of the 2D images on the display.

20. A controller for use in a multifocal display that renders a 3D scene as a series of 2D images;

the multifocal display comprising a display, an optical imaging system that is image-side telecentric, and a refractive focus actuator;

the controller coordinating adjustment of the refractive focus actuator with rendering of the 2D images on the display.