Display system where polarized light impinges on platelike laminate at brewster's angle or emerges therefrom at angle equal thereto

• US 6,507,436 B2
• Filed: 10/05/2001
• Issued: 01/14/2003
• Est. Priority Date: 06/30/1997
• Status: Expired due to Term

• Current Assignee: Central Glass Company Limited
• Original Assignee: Central Glass Company Limited
• Inventors: Kobayashi, Kazuya, Nishikawa, Shinji, Asakura, Motoh
• Primary Examiner(s): Shafer, Ricky D.
• Application Number:
  US09/970,660
• Publication Number:
  US 20020008909A1
• Time in Patent Office: 466 Days
• Field of Search: 359/485, 359/487, 359/488, 359/493, 359/494, 359/495, 359/499, 359/629, 359/630, 359/631, 359/639, 353/13, 353/14, 345/7, 156/99, 156/106, 349/11
• US Class Current: 359/485.02
• CPC Class Codes: G02B 2027/012 comprising devices for attenuating parasitic image effects
• 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 5/30 Polarising elements light-modulating devices with active elements G02F1/00
• CPC Class Codes: G02B 5/3066 involving the reflection of light at a particular angle of incidence, e.g. Brewster's angle

Abstract

The invention relates to a display system where polarized light rays from a display device impinge on a laminate at Brewster'"'"'s angle or emerge therefrom at an angle equal to Brewster'"'"'s angle. This laminate is a combination of a transparent platelike object and a functional film that is an optical rotatory film or a semitransparent film. The platelike object has a front major surface, facing the display device, and a back major surface. The display device has a polarizing member for polarizing light rays of the display device into S-wave or P-wave light rays. According to a first embodiment of the invention, the optical rotatory film is formed on the front or back major surface of the platelike object or in an inside of the platelike object, and S-wave light rays from the polarizing member are thrown against the front major surface of the laminate. With this, a part of the S-wave light rays is reflected from the front major surface of the laminate toward a viewer. The rest of the S-wave light rays is transmitted in the platelike object and converted into P-wave light rays by the optical rotatory film. Then, substantially all of the P-wave light rays emerge from the back major surface of the laminate into the air at an angle substantially equal to Brewster'"'"'s angle of the platelike object or the optical rotatory member, which borders on the back major surface of the laminate. Thus, the double image phenomenon does not arise.

Claims

1. A display system comprising:

a transparent platelike object having front and back major surfaces opposed to each other;

an optical rotatory film for rotating a plane of polarization of light rays, said optical rotatory film being formed on said front or back major surface of said platelike object or in an inside of said platelike object, a combination of said transparent platelike object and said optical rotatory film constituting a platelike laminate, said platelike laminate having front and back major surfaces; and

a display device for throwing, against said front major surface of said platelike laminate, light rays that are intended to be viewed by a viewer, said display device having a polarizing member for polarizing said light rays into P-wave light rays,

wherein said front major surface of said platelike laminate is curved such that substantially all of said P-wave light rays from said polarizing member are incident on said front major surface of said platelike laminate at Brewster'"'"'s angle.

2. A display system according to claim 1, wherein said platelike object has a thickness of up to about 2 mm, and wherein said back major surface of said platelike laminate is curved in parallel with said front major surface of said platelike laminate.

3. A display system according to claim 1, wherein said optical rotatory film is selected from the group consisting of a liquid crystal polymer film, a transparent birefringent film, and a λ

/2 phase film.

4. A display system according to claim 1, wherein said transparent platelike object is made of polymethyl methacrylate.

5. A display system according to claim 1, wherein said system is an automotive head-up display system.

6. A display system according to claim 1, wherein said display device is selected from the group consisting of a cathode-ray tube, a fluorescent display tube, and a liquid crystal display.

7. A display system according to claim 1, wherein said platelike object is a laminate of first and second plates.

8. A display system according to claim 7, wherein said optical rotatory film is interposed between said first and second plates.

9. A display system according to claim 7, wherein said platelike object has an interlayer film interposed between said first and second plates.