Abstract: A focal length measuring device comprises a light source unit for generating a collimated light, a diffraction grating for deflecting the collimated light by a deflection angle ?, and an image-pickup element for measuring a position of a focused spot light after the deflected light passes the lens to be tested. The diffracting grating is disposed near a front focal plane of the lens to be tested. The image-pickup element is disposed near a rear focal plane of the lens to be tested. A focal length is calculated according to a relationship such as h=f tan ? under condition that h indicates an image height as a distance from the optical axis. By doing this, it is possible to measure the focal length accurately and easily while restricting an influence of a depth of focus and an aberration.

Abstract: The focus detecting unit includes, a light source unit emanating a collimated light, an optical unit to be inspected, which is equipped with a container having translucency, a lens and liquid, a deflection unit which irradiates a light to the unit to be inspected by diffracting a light from the light source, a spot position detecting means 4 arranged near a backside focus plane of the optical unit to be inspected, and an operating means which calculates the composite focal length of a lens and liquid in the optical unit to be inspected by using the spot position detected by the spot position detecting means.

Abstract: An apparatus for measuring the eccentricity of the aspherical surface has a light source unit; a condenser lens condensing light rays in the proximity of the center of paraxial curvature of a surface to be examined, of an aspherical lens; an angle changing means for entering the rays on the surface to be examined, at angles ?1i (i=1, 2, . . . , N) with an optical axis; a holding tool of the aspherical lens; a light-splitting element; an imaging lens; a light-detecting element detecting the situation of light collected by the imaging lens; and an arithmetical unit. The arithmetical unit is such as to calculate the amount of eccentricity of the surface to be examined, from amounts of shift ?P1i (i=1, 2, . . . , N) between spot positions P1i (i=1, 2, . . . , N) based on the design data of the surface to be examined and spot positions P1mi (i=1, 2, . . . , N) derived from the light-detecting element, with respect to light rays Q1i (i=1, 2, . . . , N) produced by the angle changing means.

Abstract: The focus detecting unit includes, a light source unit emanating a collimated light, an optical unit to be inspected, which is equipped with a container having translucency, a lens and liquid, a deflection unit which irradiates a light to the unit to be inspected by diffracting a light from the light source, a spot position detecting means 4 arranged near a backside focus plane of the optical unit to be inspected, and an operating means which calculates the composite focal length of a lens and liquid in the optical unit to be inspected by using the spot position detected by the spot position detecting means.

Abstract: An illuminating light modulating device modulates at least one of wavelength, phase, intensity, polarization, and coherency of the light emitted to an object by an illuminating device. A pupil modulating device is disposed near a pupil plane of an objective lens, and modulates at least one of phase, intensity and direction of polarization of the luminous flux including the information of the object. An image pickup device is disposed on a plane on which the image of the object is formed by the objective lens and an imaging lens, and picks up the image of the object. An image analysis device analyzes the image of the object picked up by the image pickup device. A parameter decision device adjusts the modulation amounts of the illuminating light modulating device and the pupil modulating device by using the image information of the object analyzed by the image analysis device.

Abstract: An optical system for optical communications is composed of a transparent material having a refractive index distribution formed by changing the molar ratio of metal oxide with valence of 2 or more. The metal oxide with valence of 2 or more includes, for example, Fe2O3. Using such an optical system for optical communications, optical communication components such as an optical fiber collimator and an optical isolator are composed.

Abstract: An optical system for optical communications is composed of a transparent material having a refractive index distribution formed by changing the molar ratio of metal oxide with valence of 2 or more. The metal oxide with valence of 2 or more includes, for example, Fe2O3. Using such an optical system for optical communications, optical communication components such as an optical fiber collimator and an optical isolator are composed.

Abstract: An optical information processing apparatus includes an image display section for displaying information on an object to be processed as image information, an image information reading section for converting a light from a light source into collimate light and projecting the collimate light onto the image display section to read image information, a Fourier transform optical system for obtaining the Fourier transform of the image information read by the image information reading section, an image dividing section for dividing the image information subjected to Fourier transform at the Fourier transform optical system, a filtering section for filtering the phase or amplitude information in one piece of the image information divided by the image dividing section, an inverse Fourier transform optical system for obtaining the inverse Fourier transform of the image information filtered at the filtering section, a filtering image information acquiring section for taking in the image information subjected to inverse

Abstract: A focal length measuring device comprises a light source unit for generating a collimated light, a diffraction grating for deflecting the collimated light by a deflection angle &thgr;, and an image-pickup element for measuring a position of a focused spot light after the deflected light passes the lens to be tested. The diffracting grating is disposed near a front focal plane of the lens to be tested. The image-pickup element is disposed near a rear focal plane of the lens to be tested. A focal length is calculated according to a relationship such as h=f tan &thgr; under condition that h indicates an image height as a distance from the optical axis. By doing this, it is possible to measure the focal length accurately and easily while restricting an influence of a depth of focus and an aberration.

Abstract: An illuminating light modulating device modulates at least one of wavelength, phase, intensity, polarization, and coherency of the light emitted to an object by an illuminating device. A pupil modulating device is disposed near a pupil plane of an objective lens, and modulates at least one of phase, intensity and direction of polarization of the luminous flux including the information of the object. An image pickup device is disposed on a plane on which the image of the object is formed by the objective lens and an imaging lens, and picks up the image of the object. An image analysis device analyzes the image of the object picked up by the image pickup device. A parameter decision device adjusts the modulation amounts of the illuminating light modulating device and the pupil modulating device by using the image information of the object analyzed by the image analysis device.

Abstract: A collimator optical system collimates light from the coherent light source. A reflection type spatial light modulator returns collimated light from the collimator optical system to the collimator optical system. A Fourier transformation optical system Fourier-transforms light from the reflection type spatial light modulator and shares at least partial optical system with the collimator optical system. An emission light from another coherent light source passes through an incident light path composed of another collimator optical system, spatial modulator and polarized beam splitter in this order and reaches the reflection type spatial light modulator. Then, a reflection light from the reflection type spatial light modulator passes through a reflection light path which is reverse to the incident light path and reaches a polarized beam splitter. That is, the incident light path and reflection light path are split by the polarized beam splitter.

Abstract: A multiplexing optical system capable of processing input information at high speed and with high accuracy and having an easy-to-align simplified arrangement. A parallel-beam generating device (11, 12, 13) generates an approximately parallel light beam. An input image display device has a grating member (222) which is latticed both vertically and horizontally, and a display device (22) which displays an input image. A Fourier transform lens (31) reproduces Fourier transformed images (311) of the input image by each order of diffracted light produced by reading the input image displayed on the display device (22) by the approximately parallel light beam from the parallel-beam generating device. The Fourier transformed images (311) are reproduced on a Fourier transform plane (F2) at an approximately constant pitch (p). A filter array (322) filters the reproduced Fourier transformed images (311). A lens array (33) performs an inverse Fourier transform on each filtered light beam.

Abstract: The present invention provides a multiple image optics system which is usable for color images comprising an increased number of pixels and with white light sources as well, and enables high-speed operation processing, and which includes an object-side lens group 1 and an image-side lens array 2 with lens elements 21 arranged at a constant pitch interval, and satisfies a relation 0.8.ltoreq.q/p.ltoreq.1.0 where p represents an intercentral distance between any replicated input image 41 within an array of input images replicated on a back focal plane of the image-side lens array 2 and a replicated input image 42 nearest thereto, and q is a size of one replicated input image in the intercentral distance direction.

Abstract: A multiplexing optical system necessary for transforming input information into effective feature vectors at high speed and with high accuracy, without loss of a spatial frequency component of multiplexed object vector information, for example. Also presented are a feature vector transformation apparatus using the multiplexing optical system, and others. The multiplexing optical system performs a Fourier transform in parallel on multiplexed vector information lying in an input plane (R) as an object to be processed. The system includes a Fourier transform lens (30) for performing a Fourier transform in parallel, and satisfies the condition of (k.sub.R .lambda.f.sub.F /a<p) in an arbitrary cross-section containing an optical axis, where k.sub.