High transmittance eyewear for head-up displays

• US 10,459,224 B2
• Filed: 09/29/2014
• Issued: 10/29/2019
• Est. Priority Date: 09/29/2014
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Larson, Brent D., Lu, Kanghua, Sarma, Kalluri R.
• Primary Examiner(s): Abaza, Ayman A
• Application Number:
  US14/499,626
• Publication Number:
  US 20160091715A1
• Time in Patent Office: 1,856 Days
• Field of Search: 348 53
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/0134 of stereoscopic type
• CPC Class Codes: G02B 2027/014 comprising information/image processing systems
• CPC Class Codes: G02B 2027/0141 characterised by the informative content of the display
• 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 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 30/24 involving temporal multiplexing, e.g. using sequentially activated left and right shutters
• CPC Class Codes: G02B 30/34 Stereoscopes providing a stereoscopic pair of separated images corresponding to parallactically displaced views of the same object, e.g. 3D slide viewers
• CPC Class Codes: H04N 13/194 Transmission of image signals
• CPC Class Codes: H04N 13/344 with head-mounted left-right displays
• CPC Class Codes: H04N 13/398 Synchronisation thereof; Control thereof

Abstract

A system and method of displaying a conformal-capable head-up display image is provided. Distortions caused by combiner curvature, for example, are removed by pre-distorting and projecting separate images for each eye. Shutter-based eyewear controls the visibility as the imagery is cycled, e.g., shuttered, between left and right eyes. The combined image generator, projector and eyewear system maintains minimal vergence errors, minimal dipvergence errors, acceptable average transmittance, and optionally, high conformality.

Claims

1. An optical device for displaying a pulsed right eye display image and a pulsed left eye display image over a forward scene that is observable through a windscreen, comprising:

a first lens assembly having a transmittance versus time and configured to optically receive the pulsed right eye image and the pulsed left eye image and to cycle between absorbing the pulsed left eye image and transmitting the pulsed right eye image;

a second lens assembly having a transmittance versus time and configured to optically receive the pulsed right eye image and the pulsed left eye image and to cycle between absorbing the pulsed right eye image and transmitting the pulsed left eye image;

wherein the first and second lens assemblies comprise crossed dichroic guest-host liquid crystal lenses;

wherein each lens assembly includes a switchable retardation layer that is located between two switchable polarizers, wherein the switchable retardation layer is switchable between a nominal half-wave retardance and zero retardance and where a retardation axis of the retardation layer is oriented at 45 degrees between axes of two switchable polarizers to increase transmittance of the lens assembly; and

wherein the first lens assembly having a transmittance versus time has an average transmittance greater than 50 percent, and the second lens assembly having a transmittance versus time has an average transmittance greater than 50 percent.

2. The optical device of claim 1 wherein the average transmittance through the first and second lens assemblies is greater than 75 percent.

3. The optical device of claim 1, further comprising:

an image generator configured to apply geometric correction factors to generate a geometrically warped pulsed right eye image and a geometrically warped pulsed left eye image;

a combiner positioned to reflect the geometrically warped pulsed right eye image and generate a distortion compensated pulsed right eye image and the geometrically warped pulsed left eye image and generate a distortion compensated pulsed left eye image and to;

(i) to supply a reflected distortion compensated pulsed right eye image to an eyebox as the pulsed right eye image; and

(ii) to supply a reflected distortion compensated pulsed left eye image to the eyebox as the pulsed left eye image.

4. The optical device of claim 1 wherein the first lens assembly comprises:

a first right shuttered eyewear lens;

a second right shuttered eyewear lens, wherein the first and second right eye shuttered eyewear lenses cyclically absorb the pulsed left eye image and transmit the pulsed right eye image;

and further wherein the second eyewear lens assembly comprises;

a first left shuttered eyewear lens; and

a second left shuttered eyewear lens, wherein the first and second left shuttered eyewear lenses cyclically absorb the pulsed right eye image and transmit the pulsed left eye image.

5. The optical device of claim 3, wherein:

the combiner is a vehicle windscreen.

6. The optical device of claim 5, further comprising:

at least one windscreen sensor associated with the vehicle windscreen, each windscreen sensor configured to sense at least one parameter representative of the optical characteristics of the windscreen and supply parameter signals representative thereof to the image generator,

wherein the image generator is further configured, in response to the parameter signals, warped pulsed right eye image and the geometrically warped pulsed left eye image.

7. The optical device of claim 5, further comprising:

an avionics data source configured to supply avionics data representative of one or more avionics parameters to the image generator,

wherein the image generator is further configured, in response to the avionics data, to determine the one or more optical characteristics of the windscreen for creating the geometrically warped pulsed right eye image and the geometrically warped pulsed left eye image.

8. The optical device of claim 1, further comprising:

an image generator configured to apply geometric correction factors to generate a geometrically warped pulsed right eye image and a geometrically warped pulsed left eye image;

a pupil location tracker configured to sense locations of a right eye and a left eye of a viewer, the pupil tracker further configured to supply eye location signals representative of each eye location to the image generator,

wherein the image generator is responsive to the location signals to selectively and individually compensate each frame of the geometrically warped pulsed right eye image and the geometrically warped pulsed left eye image to vary with the locations of the right eye and left eye, respectively, of the viewer.

9. An optical device included within a head-up display system, the optical device comprising:

an image generator configured to apply geometric correction factors to generate a geometrically warped pulsed right eye image and a geometrically warped pulsed left eye image, where the geometrically warped pulsed right eye and left eye images will form a head up display image over a forward scene that is observable through a windscreen;

a combiner positioned to reflect the geometrically warped pulsed right eye image to supply a distortion compensated pulsed right eye image to an eyebox and to reflect the geometrically warped pulsed left eye image to supply a distortion compensated pulsed left eye image to the eyebox;

right eyewear having an average transmittance greater than 50 percent and configured to be cycled between absorbing and transmitting, and receiving the distortion compensated pulsed right eye image and the distortion compensated pulsed left eye image when positioned within the eyebox, and cycled to provide a pulsed right eye image during a first time period and to block the pulsed left eye image during a second time period;

left eyewear configured to be cycled between absorbing and transmitting, and receiving the distortion compensated pulsed right eye image and the distortion compensated pulsed left eye image when positioned within the eyebox, and cycled to provide a pulsed left eye image during the second time period and to block the pulsed right eye image during the first time period;

wherein the right and left eyewear comprise crossed dichroic guest-host liquid crystal lenses;

wherein each eyewear includes a switchable retardation layer that is located between two switchable polarizers, wherein the switchable retardation layer is switchable between a nominal half-wave retardance and zero retardance and where a retardation axis of the retardation layer is oriented at 45 degrees between axes of two switchable polarizers to increase transmittance of the eyewear; and

wherein an averaged transmittance over the first and second time periods of the forward scene is greater than 50 percent.

10. The optical device of claim 9 wherein the averaged transmittance over a full cycle of the first and second time periods is greater than 75 percent.

11. The optical device of claim 9 wherein the right eyewear comprises:

a first right shuttered eyewear lens;

a second right shuttered eyewear lens, wherein the first and second right shuttered eyewear lenses cyclically absorb the pulsed left eye image and transmit the pulsed right eye image;

and the left eyewear comprises;

a first left shuttered eyewear lens; and

a second left shuttered eyewear lens, wherein the first and second left shuttered eyewear lenses cyclically absorb the pulsed right eye image and transmit the pulsed left eye image.

12. The optical device of claim 9, wherein:

the combiner is a vehicle windscreen.

13. The optical device of claim 12, further comprising:

one or more windscreen sensors associated with the windscreen, each windscreen sensor configured to sense one or more parameters representative of the optical characteristics of the windscreen and supply parameter signals representative thereof to the image generator,

wherein the image generator is further configured, in response to the parameter signals, to determine the one or more optical characteristics of the windscreen for creating the geometrically warped pulsed right and left images.

14. The optical device of claim 12, further comprising:

an avionics data source configured to supply avionics data representative of one or more avionics parameters to the projector,

wherein the image generator is further configured, in response to the avionics data, to determine the one or more optical characteristics of the windscreen for creating the geometrically warped pulsed right and left images.

15. The optical device of claim 9, further comprising:

a pupil location tracker configured to sense locations of a right eye and a left eye of a viewer, the pupil tracker further configured to supply eye location signals representative of each eye location to the image generator,

wherein the image generator is responsive to the location signals to selectively and individually compensate each frame of the pulsed right eye image and the pulsed left eye image to vary with the locations of the right eye and left eye, respectively, of the viewer.

16. A method of viewing a conformal-capable display image, comprising the steps of:

alternately projecting a geometrically warped pulsed right eye image and a geometrically warped pulsed left eye image via a projector;

reflecting the geometrically warped pulsed right eye image and the geometrically warped pulsed left eye image via a combiner to provide a distortion compensated pulsed right eye image and a distortion compensated pulsed left eye image, where the geometrically warped pulsed right eye image and pulsed left eye image will form a head up display image over a conformal-capable display image that is observable through a windscreen;

cyclically absorbing the distortion compensated pulsed left eye image and transmitting a pulsed right eye image within an eyebox by a first eyewear lens assembly; and

cyclically absorbing the distortion compensated pulsed right eye image and transmitting a pulsed left eye image within the eyebox by a second eyewear lens assembly;

wherein the first and second eyewear lens assemblies comprise crossed dichroic guest-host liquid crystal lenses;

wherein each eyewear lens assembly includes a switchable retardation layer that is located between two switchable polarizers, wherein the switchable retardation layer is switchable between a nominal half-wave retardance and zero retardance and where a retardation axis of the retardation layer is oriented at 45 degrees between axes of two switchable polarizers to increase transmittance of the eyewear lens assembly; and

wherein a time averaged transmittance of the conformal-capable display image is greater than 50 percent over a full cycle of the first and second eyewear lens assemblies, where the conformal-capable display image is formed by temporally multiplexing the pulsed right eye image and the pulsed left eye image while simultaneously blocking an inappropriate image for the right eye and the left eye so that the head up display image is observable over the conformal-capable display image.

17. The method of claim 16 wherein the time averaged transmittance of the conformal-capable display image through both the first and second eyewear lens assemblies over a full cycle of both the first and second eyewear lens assemblies is greater than 75 percent.

18. The method of claim 16, further comprising:

reflecting the geometrically warped pulsed right eye image and the geometrically warped pulsed left eye image and to (i) to supply the reflected warped pulsed right eye image to the eyebox as a distortion-compensated pulsed right eye image and (ii) to supply the reflected warped pulsed left eye image to the eyebox as a distortion-compensated pulsed left eye image via a combiner.

19. The method of claim 18, further comprising:

sensing by a sensor one or more parameters representative of the optical characteristics of the combiner and supply parameter signals representative thereof to an image generator,

determining by the image generator the one or more optical characteristics of the combiner for creating the pulsed right eye image and the pulsed left eye image.

20. The method of claim 18, further comprising:

supplying by an avionics system avionics data representative of one or more avionics parameters to an image generator,

determining by the image generator the one or more optical characteristics of the combiner in response to the avionics data for creating the geometrically warped pulsed right and pulsed left eye images.

21. The method of claim 16, further comprising:

sensing via a pupil locator locations of a right eye and a left eye of a viewer;

providing eye location signals representative of each eye location to an image generator,

compensating the pulsed right eye image and the pulsed left eye image to vary with the locations of the right eye and left eye, respectively, of the viewer.

22. An optical device comprising:

right eyewear configured to be cycled between absorbing and transmitting, and receiving a pulsed right eye image and a pulsed left eye image when positioned within an eyebox, and cycled with an average transmittance of greater than 50 percent to provide the pulsed right eye image during a first time period and to block the pulsed left eye image during a second time period;

left eyewear configured to be cycled between absorbing and transmitting, and receiving the pulsed right eye image and the pulsed left eye image when positioned within the eyebox, and cycled with an average transmittance of greater than 50 percent to provide the pulsed left eye image during the second time period and to block the pulsed right eye image during the first time period;

wherein the right and left eyewear comprise crossed dichroic guest-host liquid crystal lenses;

wherein each eyewear includes a switchable retardation layer that is located between two switchable polarizers, wherein the switchable retardation layer is switchable between a nominal half-wave retardance and zero retardance and where a retardation axis of the retardation layer is oriented at 45 degrees between axes of two switchable polarizers to increase transmittance of the eyewear; and

wherein a displayed image is formed over a forward scene that is observable through a windscreen by temporally multiplexing the pulsed right eye image and the pulsed left eye image while simultaneously blocking an inappropriate image for the right eye and the left eye so that the forward scene is observable through a head up display image.