Image input apparatus
First Claim
Patent Images
1. An image input apparatus comprising:
- a first fiber optic plate in which a plurality of optical fibers are bundled together, said first fiber optic plate having an entrance surface inclined with respect to an optical axis of said each optical fiber by a predetermined slant angle θ
0 and an exit surface opposing said entrance surface;
a light source for illuminating said entrance surface; and
a holding member for holding said light source at a predetermined position, said holding member holding said light source in a state where, of incident angle components formed between a luminous flux emitted from said light source and said entrance surface, a vertical incident angle component θ
V on a plane orthogonal to a reference end on said entrance surface, said reference end defining said slant angle θ
V, is set to a range deviating from a range of stray light admissible angle X given by the following expression;
space="preserve" listing-type="equation">(X.sub.C -Θ
)≦
X≦
(X.sub.C +Θ
)wherein;
XC is a stray light admissible center angle given by an expression (90°
-sin-1 (ncore ·
sin(90°
-3θ
0)));
ncore is a refractive index of a core in said each optical fiber;
θ
0 is the slant angle;
Θ
is a total reflection critical angle in the air given by an expression (sin-1 (ncore ·
sin(90°
-SC -φ
)));
SC is a stray light admissible center angle in said each optical fiber given by an expression (sin-1 ((1/ncore)·
sin XC));
φ
is a total reflection critical angle in said each optical fiber given by an expression (sin-1 (nclad /ncore)); and
nclad is a refractive index of a cladding in said each optical fiber.
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Abstract
The present invention relates to an image input apparatus comprising a fiber optic plate and a light source for illuminating an entrance surface of the fiber optic plate. In order to obtain a vivid image, the image input apparatus according to the present invention comprises a specific structure for holding the light source at a predetermined position such that a luminous flux from the light source is made incident on the entrance surface of the fiber optic plate from a direction deviating from an angle region by which stray light can be incident on the entrance surface.
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Citations
22 Claims
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1. An image input apparatus comprising:
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a first fiber optic plate in which a plurality of optical fibers are bundled together, said first fiber optic plate having an entrance surface inclined with respect to an optical axis of said each optical fiber by a predetermined slant angle θ
0 and an exit surface opposing said entrance surface;a light source for illuminating said entrance surface; and a holding member for holding said light source at a predetermined position, said holding member holding said light source in a state where, of incident angle components formed between a luminous flux emitted from said light source and said entrance surface, a vertical incident angle component θ
V on a plane orthogonal to a reference end on said entrance surface, said reference end defining said slant angle θ
V, is set to a range deviating from a range of stray light admissible angle X given by the following expression;
space="preserve" listing-type="equation">(X.sub.C -Θ
)≦
X≦
(X.sub.C +Θ
)wherein; XC is a stray light admissible center angle given by an expression (90°
-sin-1 (ncore ·
sin(90°
-3θ
0)));ncore is a refractive index of a core in said each optical fiber; θ
0 is the slant angle;Θ
is a total reflection critical angle in the air given by an expression (sin-1 (ncore ·
sin(90°
-SC -φ
)));SC is a stray light admissible center angle in said each optical fiber given by an expression (sin-1 ((1/ncore)·
sin XC));φ
is a total reflection critical angle in said each optical fiber given by an expression (sin-1 (nclad /ncore)); andnclad is a refractive index of a cladding in said each optical fiber. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An image input apparatus comprising:
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a first fiber optic plate in which a plurality of optical fibers are bundled together, said first fiber optic plate having an entrance surface inclined with respect to an optical axis of said each optical fiber by a predetermined slang angle θ
0 and an exit surface opposing said entrance surface;a housing for accommodating said first fiber optic plate, said housing having an upper face bored with an opening for exposing said entrance surface; at least a pair of light sources for illuminating said entrance surface; and a holding member having holding sections for respectively holding said light sources such that said light sources surround at least a part of said opening of said housing, said holding sections being provided on said upper face and positioned so as to face each other across said opening of said housing; wherein said holding member holds said light sources such that, of directional vector components of a center pencil emitted from said light sources, a component on said entrance surface advances from an auxiliary end on said entrance surface opposing a reference end toward said reference end, said reference end defining said slant angle θ
0. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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Specification