# US 11,307,425 B2 · Head-up display

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,307,425 B2
- Document ID: US11307425B2
- Status: Granted
- Kind: B2
- Application number: 17/059,935
- Filed: 2019-08-22
- Published: 2021-06-24
- Granted: 2022-04-19
- Earliest claimed: 2018-08-29
- Assignees: Envisics Ltd
- Applicants: Envisics Ltd
- Inventors: Mate Karner; Jamieson Christmas
- Web page: https://patentgrep.com/patent/US11307425B2

## CPC

- G02B 27/0179: {Display position adjusting means not related to the information to be displayed}
- B60K 35/10: Input arrangements, i.e. from user to vehicle, associated with vehicle functions or specially adapted therefor
- B60K 35/23: Head-up displays [HUD] (optical aspects of head-up displays G02B27/01)
- B60K 35/28: characterised by the type of the output information, e.g. video entertainment or vehicle dynamics information; characterised by the purpose of the output information, e.g. for attracting the attention of the driver
- G02B 27/0101: {characterised by optical features (G02B27/0172 takes precedence)}
- G02B 27/0103: {comprising holographic elements}
- G02B 2027/0105: {Holograms with particular structures}
- G02B 2027/0109: {comprising details concerning the making of holograms}
- G02B 2027/0127: {comprising devices increasing the depth of field}
- G02B 2027/014: {comprising information/image processing systems}
- G02B 2027/0145: {creating an intermediate image}
- G02B 2027/0185: {Displaying image at variable distance}
- G02B 2027/0196: {having transparent supporting structure for display mounting, e.g. to a window or a windshield}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES

## Abstract

A head-up display for a vehicle having a window. The head-up display comprises a picture generating unit and a projection engine. The picture generating unit is arranged to output pictures. Each picture comprises a first picture component and a second picture component. The projection engine is arranged to receive the pictures output by the picture generating unit and project the pictures onto the window of the vehicle in order to form a first virtual image of the first picture component at a first virtual image distance and a second virtual image of the second picture component at a second virtual image distance. Light of the first picture component is polarised in a first polarisation direction and light of the second picture component is polarised in a second polarisation direction perpendicular to the first polarisation direction. The projection engine comprises an optical element having first optical power in the first polarisation direction and second optical power in the second polarisation direction such that the first virtual image distance is not equal to the second virtual image distance. The projection engine is further arranged such that the first virtual image and second virtual image at least partially overlap.

## Claims

### Claim 1

A head-up display for a vehicle having a window, the head-up display comprising:
a picture generating unit arranged to output pictures, wherein each picture comprises a first picture component and a second picture component;
a projection engine arranged to receive the pictures output by the picture generating unit and project the pictures onto the window of the vehicle in order to form a first virtual image of the first picture component at a first virtual image distance from a viewing plane and a second virtual image of the second picture component at a second virtual image distance from the viewing plane, wherein light of the first picture component is polarised in a first polarisation direction and light of the second picture component is polarised in a second polarisation direction perpendicular to the first polarisation direction,
wherein the projection engine comprises polarisation-selective mirror having: (i) a first surface arranged to receive and reflect light of the first picture component and transmit light of the second picture component, and (ii) a second surface arranged to receive and reflect light of the second picture component, wherein the first surface has first optical power in the first polarisation direction and the second surface has second optical power in the second polarisation direction such that the first virtual image distance is not equal to the second virtual image distance,
wherein the light of the first picture component forms a first light footprint on the optical element and light of the second picture component forms a second light footprint on the optical element, wherein the first light footprint and second light footprint at least partially overlap.

### Claim 2 (depends on 1)

A head-up display as claimed in claim 1 wherein the projection engine is arranged such that the light ray bundle received by the optical element and forming the second virtual image is at least partially contained within the light ray bundle received by the optical element and forming the first virtual image.

### Claim 3 (depends on 1)

A head-up display as claimed in claim 1 wherein the first picture component and second picture component are coplanar.

### Claim 4 (depends on 1)

A head-up display as claimed in claim 1 wherein the first surface is a first freeform optical surface and the second surface is a second freeform optical surface having a different surface profile to the first freeform optical surface.

### Claim 5 (depends on 1)

A head-up display as claimed in claim 1 wherein the first surface is reflective to at least one wavelength of the light of the first picture component and transmissive to other wavelength/s, and the second surface is reflective to at least one wavelength of the light of the second picture component.

### Claim 6 (depends on 1)

A head-up display as claimed in claim 1 wherein the first picture component is a far-field image and the second picture component is a near-field image.

### Claim 7 (depends on 1)

A head-up display as claimed in claim 1 wherein the first polarisation direction is at an angle of π/4 to the s-polarisation direction of the window.

### Claim 8 (depends on 1)

A head-up display as claimed in claim 1 wherein the first polarisation direction is the s-polarisation direction of the window and the second polarisation direction is the p-polarisation direction of the window, and the projection engine further comprises a quarter-wave plate arranged to receive the light of the first picture component and the light of the second polarisation component such that light of the pictures projected onto the window of the vehicle is circularly polarised.

### Claim 9 (depends on 8)

A head-up display as claimed in claim 8 wherein the head-up display comprises a glare trap window and the quarter-wave plate is a coating on the glare trap window.

### Claim 10 (depends on 8)

A head-up display as claimed in claim 8 wherein the quarter-wave plate is a coating on the window.

### Claim 11 (depends on 1)

A head-up display as claimed in claim 1 wherein the picture generating unit comprises:
a light source arranged to emit light; and
a spatial light modulator arranged to receive the light from the light source and spatially-modulated the light in accordance with computer-generated holograms displayed on the spatial light modulator to form a holographic reconstruction corresponding to each picture.

### Claim 12 (depends on 11)

A head-up display as claimed in claim 11 wherein the picture generating unit further comprises a light-receiving surface arranged to receive the spatially-modulated light such that each picture is formed thereon.

### Claim 13 (depends on 1)

A head-up display as claimed in claim 1 wherein the window is a windscreen.

### Claim 14

A head-up display for a vehicle having a window, the head-up display comprising:
a picture generating unit arranged to output pictures, wherein each picture comprises a first picture component and a second picture component; and
a projection engine arranged to receive the pictures output by the picture generating unit and project the pictures onto the window of the vehicle in order to form a first virtual image of the first picture component at a first virtual image distance and a second virtual image of the second picture component at a second virtual image distance, wherein light of the first picture component is polarised in a first polarisation direction and light of the second picture component is polarised in a second polarisation direction perpendicular to the first polarisation direction,
wherein the projection engine comprises polarisation-selective mirror having: (i) a first surface arranged to receive and reflect light of the first picture component and transmit light of the second picture component, and (ii) a second surface arranged to receive and reflect light of the second picture component, wherein the first surface has first optical power in the first polarisation direction and the second surface has second optical power in the second polarisation direction such that the first virtual image distance is different to the second virtual image distance.

### Claim 15

A method of providing a head-up display for a vehicle having a window, the method comprising:
providing a plurality of pictures, each picture comprising a first picture component and a second picture component;
projecting the pictures onto the window of the vehicle in order to form a first virtual image of the first picture component at a first virtual image distance from a viewing plane and a second virtual image of the second picture component at a second virtual image distance from the viewing plane, wherein light of the first picture component is polarised in a first polarisation direction and light of the second picture component is polarised in a second polarisation direction perpendicular to the first polarisation direction,
wherein the projection comprises receiving light of the first picture component and light of the second picture component at a polarisation-selective mirror having: (i) a first surface arranged to receive and reflect light of the first picture component and transmit light of the second picture component, and (ii) a second surface arranged to receive and reflect light of the second picture component, wherein the first surface has first optical power in the first polarisation direction and the second surface has second optical power in the second polarisation direction such that the first virtual image distance is not equal to the second virtual image distance, and
wherein the light of the first picture component forms a first light footprint on the optical element and light of the second picture component forms a second light footprint on the optical element, wherein the first light footprint and second light footprint at least partially overlap.