Holographic rearview mirror and method of producing same

• US 4,988,152 A
• Filed: 01/06/1987
• Issued: 01/29/1991
• Est. Priority Date: 01/06/1987
• Status: Expired due to Term

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Wreede, John E.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Callaghan, Terry S.
• Application Number:
  US07/000,797
• Time in Patent Office: 1,484 Days
• Field of Search: 350/3.7, 350/3.61, 350/174
• US Class Current: 359/15
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G03H 2001/043 Non planar recording surface, e.g. curved surface

Abstract

An improved rearview mirror and process for producing the same is provided wherein an elongated substrate member is configured for attachment to the interior of a windshield. The substrate member supports an image retaining coating defining a holographic reflective surface that is configured to be substantially normal to the line of sight of the driver despite the slope of the windshield. As a result, a thin distortion free mirror can be provided with an expanded line of sight for the driver.

Claims

1. A combination vehicle windshield and rearview mirror comprising:

a curved transparent substrate adapted for mounting on a portion of the vehicle windshield while permitting observation of the forward motion of the vehicle;

a thin film holographic optical reflective element laminated onto the substrate to provide a reflection of light coming from the rear of the vehicle to the driver, the optical element further limiting transmission of only some of the light coming from the front of the vehicle to the driver; and

a pair of reflective holograms developed on the coating at wavelength bands having different maximum wavelength peaks.

2. The invention of claim 1 further comprising parallel fringe provided by the coating.

3. The invention of claim 1 further comprising non-parallel fringe to compensate for the curvature of the rearview windshield.

4. The invention of Claim 1 further comprising a parallel tilted fringe reflection image provided by the coating, the tilt being set at exposure of an image to compensate for the slope of the windshield in the plane extending along the line of sight of a driver to prevent distortion.

5. The invention of claim 1 wherein the substrate is an elongated flexible transparent member.

6. The invention of claim 1 further including an adhesive coating on the substrate for attachment to the interior windshield surface.

7. A combination vehicle windshield and rearview mirror comprising:

a curved transparent substrate adapted for mounting on a portion of the vehicle windshield while permitting observation of the forward motion of the vehicle;

a thin film holographic optical reflection element laminated onto the substrate to provide a reflection of light coming from the rear of the vehicle to the driver, the optical element further limiting transmission of only some of the light coming from the front of the vehicle to the driver wherein the image coating is poly-N-vinyl carbazole.

8. The invention of claim 7 further comprising parallel fringes provided by the coating.

9. The invention of claim 7 further comprising non-parallel fringes to compensate for the curvature of the rearview windshield.

10. The invention of claim 7 further comprising parallel tilted fringes provided by the coating, the tilt being set at exposure of an image to compensate for the slope of the windshield in the plane extending along the line of sight of a driver to prevent distortion.

11. The invention of claim 7 further including a pair of reflective holographic images developed on the coating at wavelength bands having different maximum wavelength peaks.

12. The invention of claim 11 wherein the maximum peaks are at 650 nanometers and 500 nanometers.

13. The invention of claim 7 wherein the substrate is an elongated flexible transparent member.

14. The invention of claim 7 further including an adhesive coating on the substrate for attachment to the interior windshield surface.

15. A combination vehicle windshield and rearview mirror comprising:

a curved transparent substrate adapted for mounting on a portion of the vehicle windshield while permitting observation of the forward motion of the vehicle;

a thin film holographic optical reflective element laminated onto the substrate to provide a reflection of light coming from the rear of the vehicle to the driver, the optical element further limiting transmission of only some of the light coming from the front of the vehicle to the driver; and

a pair of reflective holographic images developed on the coating at wavelength bands having different maximum wavelength peaks, wherein the maximum peaks are at 650 nanometers and 500 nanometers.