Image pickup apparatus having a beam limiting member
First Claim
1. An image pickup apparatus comprising:
- an optical system for forming an image of an object;
an image pickup device;
a beam limiting member having a light-transmitting portion and a light blocking portion, said beam limiting member being positioned between said object and said image pickup device to limit a beam diameter, thereby generating a light beam having an aperture number not less than F4 at all times;
said image pickup apparatus satisfying the following conditions;
(1) 1.5<
φ
/P×
√
{square root over ( )}(2.5/N)<
8.0(2) 0.0015<
P<
0.0055 [millimeter](3) 2.4<
N<
20 [million]where Ø
is a size (given in millimeters) of a diameter of 90% encircled energy of a point spread function by amplitude of the optical system approximately at a center of an image plane, exclusive of low-pass action by an optical low-pass filter, for a wavelength of e-line at an aperture number F5.6;
N is the number of pixels (given in million) of the image pickup device; and
P is a pixel pitch (given in millimeters) of the image pickup device.
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Accused Products
Abstract
The present invention relates to a compact and low-cost image pickup apparatus that is capable of photographing a high-quality image comparable to silver halide photographs even when the image is enlarged to 8×10″ size or larger and that enables the depth of field to be controlled with an aperture number exceeding F4. In the image pickup apparatus, an image of an object produced by an optical system (10) is formed on an electronic image pickup device (20), thereby obtaining image information concerning the object. The optical system (10) has a structure capable of obtaining an aperture number equal to or larger than F4 by reducing the beam diameter. Performance required for the optical system (10) is such that the size of the diameter of 90% encircled energy of the point spread function by amplitude is allowed to be up to about 8 times larger than the pixel pitch corresponding to the resolvable pixel unit. The pixel pitch of the image pickup device (20) is not larger than about 5 micrometers. The number of pixels is not less than about 2.5 million, which meets the resolvable pixel unit.
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Citations
7 Claims
-
1. An image pickup apparatus comprising:
-
an optical system for forming an image of an object; an image pickup device; a beam limiting member having a light-transmitting portion and a light blocking portion, said beam limiting member being positioned between said object and said image pickup device to limit a beam diameter, thereby generating a light beam having an aperture number not less than F4 at all times; said image pickup apparatus satisfying the following conditions; (1) 1.5<
φ
/P×
√
{square root over ( )}(2.5/N)<
8.0(2) 0.0015<
P<
0.0055 [millimeter](3) 2.4<
N<
20 [million]where Ø
is a size (given in millimeters) of a diameter of 90% encircled energy of a point spread function by amplitude of the optical system approximately at a center of an image plane, exclusive of low-pass action by an optical low-pass filter, for a wavelength of e-line at an aperture number F5.6;
N is the number of pixels (given in million) of the image pickup device; and
P is a pixel pitch (given in millimeters) of the image pickup device. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification