Fibre-optics faceplate observable with high-intensity ambient illumination

• US 3,907,403 A
• Filed: 06/18/1974
• Issued: 09/23/1975
• Est. Priority Date: 07/28/1969
• Status: Expired due to Term

• Current Assignee: Haruo Maeda
• Original Assignee: Haruo Maeda
• Inventors: Maeda, Haruo
• Primary Examiner(s): Rubin, David H.
• Application Number:
  US05/480,364
• Time in Patent Office: 462 Days
• Field of Search: 350/96B,276R,164,165,188 313/372,475
• US Class Current: 385/120
• CPC Class Codes: G02B 6/08 with fibre bundle in form of plate
• CPC Class Codes: H01J 29/892 using fibre optics

Abstract

A fibre-optics faceplate for displaying an optical image of high image contrast that is suitable for visual observation under high-intensity ambient illumination. The faceplate is a bundle of side-by-side optical fibres, each having a core with a low numerical aperture of below about 0.4, cladding therearound having an index of refraction less than that of the core, and a light-absorbent glass layer around the cladding. The outer surface of the bundle is roughened and has a coating thereon with an index of refraction less than that of the cores. The inner surface has a fluorescent material thereon for emitting optical signals by application thereto of electrical signals.

Claims

1. A FIBRE OPTICS FACEPLATE HAVING A NEARLY BLACK SURFACE, FOR DISPLAYING AN OPTICAL IMAGE OF HIGH CONTRAST UNDER HIGH-INTENSITY AMBIENT ILLUMINATION CONDITIONS, COMPRISING:

A. A SCREEN FORMED OF A BUNDLE OF SIDE-BY-SIDE OPTICAL FIBRES, COMPRISING CORES HAVING A SELECTED INDEX OF REFRACTION, CLADDINGS ENVELOPING EACH OF SAID CORES, AND ABSORBING GLASS LAYERS DISPOSED BETWEEN SAID CLAD CORES, SAID BUNDLE HAVING AN OUTER SURFACE AND AN INNER SURFACE AT THE OPPOSED ENDS OF SAID FIBRES;

B. AS A LIGHT-SCATTERING MEANS FOR AMBIENT LIGHT PASSING THROUGH SAID CORES FROM SAID OUTER SURFACE, A FLUORESCENT LAYER AS A COATING ON SAID INNER SURFACE;

C. A MININIZING MEANS FOR AMBIENT LIGHT THAT IS INCIDENT UPON SAID DARK SURFACE, COMPRISING;

2. LIGHT ABSORPTION CAPABILITY IN SAID ABSORBING GLASS LAYERS FOR ABSORBING SAID OUTWARDLY REFLECTED AMBIENT LIGHT PASSING THROUGH SAID CLADDINGS.

3. A TRANSPARENT COATING WHICH COVERS SAID COARSE FINISHED OUTER SURFACE, SAID COATING HAVING A REFRACTIVE INDEX LOWER THAN SAID REFRACTIVE INDEX OF SAID CORES AND HAVING A RANGE OF TRANSPARENCY SELECTED IN CONSIDERATION OF THE RELATIONSHIP BETWEEN THE WAVELENGTH CHARACTERSITIC OF THE LIGHT EMITTED FRM SAID FLOUORESCENT LAYER AND THE SPECTRAL SENSITIVITY OF AN OBSERVER'"'"''"'"'S EYES, WHEREBY INTERFERENCE OF SAID AMBIENT LIGHT WITH SAID IMAGE IS MINIMIZED AND SAID NARROWED VIEWING ANGLE IS WIDENED:

AND D. A LIGHT ABSORPTION MEANS FOR SAID RANDOMLY SCATTERED AMBIENT LIGHT ENTERING SAID CORES THROUGH SAID TRANSPARENT COATING AND FOR SAID AMBIENT LIGHT SCATTERED BACK INTO SAID CORES BY SAID FLUORESCENT LAYER, COMPRISING;