Display systems and methods for determining registration between a display and a user's eyes
A wearable device may include a head-mounted display (HMD) for rendering a three-dimensional (3D) virtual object which appears to be located in an ambient environment of a user of the display. The relative positions of the HMD and one or more eyes of the user may not be in desired positions to receive, or register, image information outputted by the HMD. For example, the HMD-to-eye alignment may vary for different users and change over time (e.g., as a given user moves around or as the HMD slips or otherwise becomes displaced). The wearable device may determine a relative position or alignment between the HMD and the user's eyes. Based on the relative positions, the wearable device may determine if it is properly fitted to the user, may provide feedback on the quality of the fit to the user, and may take actions to reduce or minimize effects of any misalignment.
1. A display system configured to project light to an eye of a user to display virtual image content, the display system comprising:
a frame configured to be supported on a head of the user;
a head-mounted display disposed on the frame, the display configured to project light into the user's eye to display virtual image content with different amounts of wavefront divergence to present virtual image content appearing to be located at different depths at different periods of time;
one or more eye-tracking cameras configured to image the user's eye; and
processing electronics in communication with the display and the one or more eye-tracking cameras, the processing electronics configured to:
define a registration volume relative to the display based on one or more parameters;
determine a position of the eye based on images of the eye obtained with the one or more eye-tracking cameras;
determine whether the position of the eye is within the registration volume of the head-mounted display system; and
control operation of the display based on determining whether the position of the eye is within the display registration volume,
wherein the processing electronics are configured to control operation of the display by causing the display to boost a brightness of a plurality of pixels of the display relative to other pixels of the display, wherein the plurality of pixels with a boosted brightness comprise pixels expected to undergo perceived dimming under improper registration.
2. The display system of claim 1 , wherein the one or more parameters comprise a type of application that is running on the display system.
3. The display system of claim 1 , wherein the one or more parameters comprise one or more physical parameters of the head-mounted display.
4. The display system of claim 1 , wherein the one or more parameters of the head-mounted display comprise one or more of a display field of view, a display surface size, a shape of the display, an outer housing of the display, or an amount of optical power imparted by the display to light representing virtual image content.
5. The display system of claim 1 , wherein the processing electronics are configured to control operation of the display by presenting virtual image content to the user indicating at least that the display and the eye are not properly registered.
6. The display system of claim 1 , wherein the processing electronics are further configured to, upon determining that the position of the eye is outside of the display registration volume, provide feedback to the user that the head-mounted display is not properly adjusted to fit the user, wherein the feedback is a notification provided based on determining whether the position of the eye is within the display registration volume.
7. The display system of claim 1 , further comprising at least one interchangeable fit piece removably mounted to the frame and configured to adjust a fit of the frame.
8. The display system of claim 7 , wherein the at least one interchangeable fit piece comprises an interchangeable nose bridge configured to adjust the fit of the frame between the frame and a nose bridge of the user.
9. The display system of claim 7 , wherein the at least one interchangeable fit piece comprises an interchangeable forehead pad configured to adjust the fit of the frame between the frame and a forehead of the user.
10. The display system of claim 7 , wherein the at least one interchangeable fit piece comprises an interchangeable back pad configured to adjust the fit of the frame between the frame and a back of the head of the user.
11. The display system of claim 7 , wherein controlling operation of the display comprises providing feedback to the user that the head-mounted display is not properly adjusted to fit the user and providing a suggestion to the user to swap a currently-installed interchangeable fit piece for another interchangeable fit piece.
12. The display system of claim 1 , further comprising one or more light sources disposed on the frame with respect to the user's eye to illuminate the user's eye, the one or more eye-tracking cameras forming images of the eye using the light from the one or more light sources.
13. The display system of claim 12 , wherein the one or more light sources comprise at least two light sources disposed on the frame with respect to the user's eye to illuminate the user's eye.
14. The display system of claim 12 , wherein the one or more light sources comprise infrared light emitters.
15. The display system of claim 12 , wherein the one or more light sources form one or more glints on the eye, and wherein the processing electronics are configured to determine a location of a cornea of the user's eye based on the one or more glints.
16. The display system of claim 1 , wherein the position of the eye is a location of a center of rotation of the eye.
17. The display system of claim 1 , wherein a cornea of the user's eye has associated therewith a cornea sphere having a center of curvature and the processing electronics are configured to determine a location of the center of curvature of the cornea sphere.
18. The display system of claim 1 , further comprising:
a waveguide stack comprising a plurality of waveguides configured to provide image content on a plurality of depth planes.
19. The display system of claim 18 , wherein each waveguide of the waveguide stack comprises a diffractive optical element, and wherein diffractive optical elements of some waveguides are configured to output light with a different amount of wavefront divergence than the diffractive optical elements of other waveguides.
20. The display system of claim 1 , wherein the registration volume is a three-dimensional (3D) volume of space that is defined with reference to the display such that the virtual image content is received by the user's eye while the user's eye is situated within the registration volume, and such that the virtual image content is not received by the user's eye, or the virtual image content is dimmed, while the user's eye is not situated within the registration volume.