HEAD UP DISPLAY LENS

• US 20150029410A1
• Filed: 01/09/2013
• Published: 01/29/2015
• Est. Priority Date: 01/20/2012
• Status: Abandoned Application

• Current Assignee: BAE Systems Plc
• Original Assignee: BAE Systems Plc
• Inventors: Laycock, Leslie Charles, Stace, Christopher, Culfaz, Ferhat
• Application Number:
  US14/373,128
• Publication Number:
  US 20150029410A1
• Time in Patent Office: Days
• US Class Current: 349/11
• CPC Class Codes: G02B 1/11 Anti-reflection coatings
• CPC Class Codes: G02B 2027/0112 comprising device for genereting colour display
• CPC Class Codes: G02B 2027/012 comprising devices for attenuating parasitic image effects
• CPC Class Codes: G02B 2027/0127 comprising devices increasing the depth of field
• CPC Class Codes: G02B 2027/013 comprising a combiner of particular shape, e.g. curvature
• CPC Class Codes: G02B 2027/0141 characterised by the informative content of the display
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/145 having sequential partially reflecting surfaces
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence

Abstract

The following invention relates to an improved lens apparatus for use in a head up display (HUD), particularly for providing HUD with a depth of field and more particularly with providing a secondary virtual image in a different colour so as to provide a warning message.

The partially reflecting combiner has a first surface S₁ located closest to a display, and a second surface S₂, located furthest from the display, wherein the effective radius of curvature of surface S₂>S₁, so as to provide two non-coincident virtual images.

The selection of antireflective coatings on the surfaces S₂ and S₁ allows the non-coincident virtual images to have different coloured virtual images.

Claims

1. A display device for vehicles comprising:

a display which provides system information that is to be displayed to a user; and

a partially reflecting combiner, which magnifies the system information from the display, and provides a virtual image of said display;

wherein said partially reflecting combiner has a first curved surface S₁ and a second curved surface S₂, the first curved surface S₁ being closer to the display than the second curved surface S₂, wherein the radii of curvature of surface S₂>

S₁, so as to provide two non-coincident virtual images.

2. A display device according to claim 1 wherein the partially reflecting combiner is a negative meniscus lens.

3. A display device according to claim 1, wherein the radius of curvature, R₂, of surface S₂ is adjusted to generate a secondary virtual image that appears in front of a primary virtual image generated by surface S₁.

4. A display device according to claim 1 wherein the volume between S₁ and S₂ is filled with a material of refractive index n, wherein the effective curvature of R′

₂ is given by

5. A display device according to claim 1 wherein at least one anti-reflection coating is applied to at least one of surfaces S₁ or S₂.

6. A display device according to claim 5 wherein there is at least one anti-reflection coating on surface S₁ and at least one anti-reflection coating on surface S₂.

7. A display device according to claim 6, wherein the anti-reflection coating on S₁ is selected, such that S₁ has a reflectance minima in a first narrow wave band.

8. A display device according to claim 7 wherein the anti-reflection coating on S₂ is selected to have a reflectance maxima in substantially the first narrow wave band, such that a secondary virtual image projected from surface S₂ is presented in front of a primary virtual image from the surface S₁.

9. A display device according to claim 7 wherein the first narrow wave band, is selected to provide a warning secondary virtual image, to provide a warning or danger information in front of a primary virtual image from the surface S₁.

10. A display device according to claim 1 wherein the two non-coincident virtual images include a secondary virtual image and a primary virtual image that are separated by a distance in the range of from 200 mm to 600 mm.

11. A display device according to claim 1 wherein the display is a liquid crystal on silicon (LCOS) device, illuminated by narrowband red, green and blue LED sources.

12. A display device according to claim 11, wherein there is at least one anti-reflection coating on surface S₁ and at least one anti-reflection coating on surface S₂ and wherein the anti-reflection coatings on S₁ and S₂ are selected such that only the narrowband red LED from the LCOS device is reflected by the surface coating on S₂, so as to provide red warning or danger information to the user.

13. A display device according to claim 1 wherein the curvature of surface S₂>

S₁.

20. A display device according to claim 1 wherein the display is a liquid crystal on silicon (LCOS) device, illuminated by red, green and blue LED sources, and wherein there is at least one anti-reflection coating on surface S₁ and at least one anti-reflection coating on surface S₂, and wherein the anti-reflection coatings on S₁ and S₂ are selected such that only the red LED from the LCOS device is reflected by the surface coating on S₂, so as to provide red warning or danger information to the user.

14. A display device comprising:

a display which provides information that is to be displayed to a user; and

a partially reflecting combiner configured to magnify the system information from the display, said partially reflecting combiner having a first curved surface S1 and a second curved surface S2, the first curved surface S1 being closer to the display than the second curved surface S2, wherein the radii of curvature of surface S2>

S1, so as to provide two non-coincident virtual images, the images including a primary virtual image and a secondary virtual image.

15. A display device according to claim 14, wherein the radius of curvature, R₂, of surface S₂ is adjusted to generate the secondary virtual image that appears in front of the primary virtual image generated by surface S₁.

16. A display device according to claim 15 wherein there is at least one anti-reflection coating on surface S₁ and at least one anti-reflection coating on surface S₂.

17. A display device according to claim 16, wherein the anti-reflection coating on S₁ is selected, such that S₁ has a reflectance minima in a first narrow wave band.

18. A display device according to claim 17 wherein the anti-reflection coating on S₂ is selected to have a reflectance maxima in substantially the first narrow wave band, such that the secondary virtual image projected from surface S₂ is presented in front of the primary virtual image from the surface S₁.

19. A display device according to claim 17 wherein the first narrow wave band is selected to provide the secondary virtual image, so as to provide a warning or danger information in front of the primary virtual image from the surface S₁.