Display source

• US 20090015735A1
• Filed: 10/18/2006
• Published: 01/15/2009
• Est. Priority Date: 11/10/2005
• Status: Active Grant

• Current Assignee: BAE Systems Plc
• Original Assignee: BAE Systems Plc
• Inventors: Simmonds, Michael David
• Granted Patent: US 7,777,819 B2
• Time in Patent Office: Days
• US Class Current: 349/11
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00

Abstract

A helmet mounted display 30 includes a display source 31 arranged to be directly imaged by a primary relay optical arrangement 32 having relay optical elements 33A, 33B and 33C. Light exiting the primary relay optical arrangement 32 indicated by ray traces 34A, 34B and 34C continue towards a visor 35 which is arranged to reflect incident light to a exit pupil located in a convenient position for a viewer 36.

The display source 31 includes a light source, beam splitter, reflective liquid crystal display and a display source relay optical arrangement to provide an output image at an output diffuser screen. The image at the output screen is then directly imaged by the primary relay optical arrangement 32.

Should the reflective liquid crystal display require modification or replacement with a newer model, then the display source 31 can be redesigned to accommodate the new reflective liquid crystal display rather than re-engineering the primary relay optical arrangement 32 at greater expense.

Claims

1. A display source, including:

a light source generator arranged to generate light including linearly polarized light of a first predetermined type;

a beam splitter being arranged to substantially transmit incident linearly polarized light of the first predetermined type through the beam splitter and to substantially reflect incident linearly polarized light of a second predetermined type from the beam splitter;

an image generator including a plurality of display pixels, each pixel including a predetermined state being arranged to reflect and convert incident linearly polarized light of the first predetermined type into linearly polarized light of the second predetermined type;

a display source relay optical arrangement;

an output screen arrangement; and

the display source relay optical arrangement being arranged to transmit linearly polarized light of the second predetermined type reflected from the image generator via the beam splitter to the output screen arrangement.

2. A display source, as claimed in claim 1, wherein the light source generator includes a light source and an illuminator lens.

3. A display source, as claimed in claim 1, wherein the image generator includes a reflective liquid crystal display.

4. A display source, as claimed in claim 3, wherein a field lens is arranged between the reflective liquid crystal display and the beam splitter.

5. A display source, as claimed in claim 1, wherein the predetermined state of the display pixels of the image generator reflect and convert incident linearly polarized light of the first predetermined type into linearly polarized light of the second predetermined type to form a desired image to be displayed on the output screen arrangement.

6. A display source, as claimed in claim 1, wherein the linearly polarized light of the first predetermined type is p-polarised light.

7. A display source, as claimed in claim 1, wherein the linearly polarized light of the second predetermined type is s-polarised light.

8. A display source, as claim in claim 1, wherein the display source relay optical arrangement includes a relay lens arrangement.

9. A display source, as claimed in claim 8, wherein a fold mirror is arranged between the relay lens arrangement and the output screen arrangement.

10. A display source, as claim in claim 1, wherein a compensator plate is arranged between the beam splitter and display source relay optical arrangement.

11. A display source, as claimed in claim 4, wherein a compensator plate is arranged between the reflective liquid crystal display and field lens.

12. A display source, as claimed in claim 8, wherein the relay lens arrangement includes a first singlet lens, a first doublet lens, a second signal lens and a second doublet lens arranged in series with respect to one another.

13. A display source, as claimed in claim 1, wherein the output screen arrangement includes an output diffuser.

14. A display source, as claimed in claim 13, wherein a field lens is arranged between the output diffuser screen and the screen display source relay optical arrangement.

15. A helmet mounted display or head mounted display including a display source as claimed in claim 1, including a primary relay lens arrangement and a visor, the primary lens arrangement arranged to transmit light from the output screen arrangement to the visor and the visor arranged to reflect incident light to a viewer.

16. A helmet mounted display or head mounted display, as claimed in claim 15, including a projector lens arranged between the display source and the primary relay lens arrangement.

17. A helmet mounted display or head mounted display, including a primary relay lens arrangement and a visor, the helmet mounted display or head mounted display further including a display source as claimed in claim 1, the display source being arranged to provide image bearing light to the primary relay lens arrangement which in turn is arranged to transmit the image bearing light to the visor, the display source also being interchangeable with a replacement display source without the need to alter the primary relay lens arrangement of the helmet mounted display of head mounted display.