Holographic display apparatus
AssigneesCentral Glass Company, Limited, Nissan Motor Co., Ltd.
InventorsTomohisa Ishikawa, Yoshinori Akamatsu, Junichi Fukano, Masayuki Hori
Life of this patent
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Abstract
A holographic display apparatus reconstructs an image by projecting a beam of a luminous source to a holographic sheet including a plurality of holograms. The holograms are arranged so that the central axes of images recorded in the holographic sheet are directed in a same direction, in the diverging direction, or in a converging direction. Additionally, each hologram has a first focal distance f1 (mm) and a second focal distance f2 (mm) which are in a relationship such that f1.ltoreq.f2/28+50 and f1<f2.
Claims9
A holographic display apparatus, comprising:
- a holographic sheet of a transparent type including a plurality of holograms therein, said holograms being formed from a first lens at a first distance f1 (mm) from said holographic sheet and a second lens at a second distance f2 (mm) from said holographic sheet which are in a relationship such that f1.ltoreq.f2/28+50 and f1<f2;
- and
- a luminous source which illuminates said holograms which form an image recorded in said holographic sheet.
A high mounted stop lamp for an automotive vehicle, comprising:
- a holographic sheet of a transparent type installed to a rear window glass of the automotive vehicle, said holographic sheet including a plurality of holograms which are formed from a first lens at a first distance f1 (mm) from said holographic sheet and a second lens at a second distance f2 (mm) from said holographic sheet which are in a relationship such that f1.ltoreq.f2/28+50 and f1<f2;
- and
- a luminous source disposed in the vicinity of a rear parcel of the automotive vehicle and illuminating said holograms so that said holograms form an image recorded in said holographic sheet on receiving beams from said luminous source.
A method of producing a holographic sheet of a transparent type for use in a holographic display apparatus comprising the steps of:
- (a) coating a photosensitive material on an optically transparent film;
- and
- (b) exposing photosensitive material on the film in such a manner that a laser beam is divided into first and second beams by a beam splitter, the first beam being directed to a first convex lens disposed at a first distance f1 (mm) from the film by a first reflective mirror and through the first convex lens, the first beam diverging into a spherical wave illuminating a part of the photosensitive coating layer of the film, the second beam being directed to a second convex lens which is disposed at a second distance f2 (mm) from the film by a second reflective mirror and through the second convex lens, the laser beam diverging into a spherical wave illuminating the same part as that illuminated by the first beam from the other direction relative to the first beam;
- wherein the first distance f1 (mm) and the second distance f2 (mm) are in a relationship such that f1.ltoreq.f2/28+50 and f1<f2.
Dependencies are inferred from the claim text.