Imaging device
AssigneeOlympus Optical Co., Ltd.
InventorYoshiharu Takasugi
Life of this patent
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Abstract
An imaging device has an optical low-pass filter and a solid-state image sensor. The optical low-pass filter includes a plurality of birefringent plates. When a plurality of spaced spots formed by the birefringent plates with respect to incident light are located at adjacent positions such as to be regarded as one spot on the birefringent plates, the birefringent plates are constructed so that a phase difference between light waves passing through the plurality of spaced spots with respect to any wavelength in a visible wavelength region is larger than the wavelength. Thus, the imaging device, even when using many quartz filters, makes the intensities of the spaced spots uniform and can secure the optical low-pass filter free of dependence of wavelength.
Claims15
An imaging device comprising:
- an imaging optical system;
- an optical low-pass filter including a plurality of first birefringent plates, thereby incident light being separated to be emergent from a plurality of spots on a last surface of said plurality of first birefringent plates from an entrance side;
- and
- a solid-state image sensor;
- said plurality of spots including spots located adjacent to one another with a distance therebetween being approximately equal to or less than three times a Rayleigh limit determined dependent on an F number of said imaging optical system;
- and
- said plurality of first birefringent plates being constructed so that a phase difference between light waves respectively emergent from said spots located adjacent to one another is larger than a wavelength of said light waves in a visible wavelength region.
An imaging device comprising:
- an imaging optical system;
- an optical low-pass filter including a plurality of birefringent plates, thereby incident light being separated to be emergent from a plurality of spots on a last surface of said plurality of birefringent plates from an entrance side;
- and
- a solid-state image sensor;
- said plurality of spots formed by at least a second one of said plurality of birefringent plates from an entrance side of said birefringent plates on an exit surface of said at least said second one of said plurality of birefringent plates with respect to said incident light including spots located adjacent to one another with a distance therebetween being approximately equal to or less than three times a Rayleigh limit determined dependent on an F number of said imaging optical system;
- and
- said plurality of birefringent plates being constructed so that a phase difference between light waves emergent respectfully from said spots located adjacent to one another is larger than a wavelength of said light waves in a visible wavelength region, with orientations of crystal axes of said plurality of birefringent plates selected so as not to change a geometrical pattern of said plurality of spots on said exit surface of said at least said second one of said plurality of birefringent plates.
An imaging device comprising:
- an imaging optical system;
- an optical low-pass filter including a plurality of birefringent plates, thereby incident light being separated to be emergent from a plurality of spots on a last surface of said plurality of birefringent plates from an entrance side;
- and
- a solid-state image sensor;
- said plurality of spots formed by at least a second one of said plurality of birefringent plates from an entrance side of said plurality of birefringent plates on an exit surface of said at least said second one of said plurality of birefringent plates with respect to said incident light including spots located adjacent to one another with a distance therebetween being approximately equal to or less than three times a Rayleigh limit determined dependent on an F number of said imaging optical system;
- and
- said plurality of birefringent plates being constructed so that a phase difference between light waves emergent respectfully from said spots located adjacent to one another is larger than a wavelength of said light waves in a visible wavelength region, by changing a relative relationship between an orientation of a crystal axis of said at least said second one of said plurality of birefringent plates and an orientation of a crystal axis of each of said plurality of birefringent plates disposed before said at least said second one of said plurality of birefringent plates by an angle of 180.degree. without changing a geometrical pattern of said plurality of spots on said exit surface of said at least said second one of said plurality of birefringent plates.
Dependencies are inferred from the claim text.