Abstract: By using an offset parabolic concave mirror as a concave mirror, and arranging a lens having an entrance pupil at the geometric focal point of the offset parabolic concave mirror, a group of rays incident parallel to the optical axis of the offset parabolic concave mirror become chief rays which are telecentric with respect to an object plane orthogonal to the optical axis of the offset parabolic concave mirror, and diverging light from each object point on the object plane can be detected on a quadric image plane formed by the lens at the focal point of the offset parabolic concave mirror without blind spots. An image of the target object is detected after the beams reflected by the offset parabolic concave mirror are bent by the reflecting mirrors and made incident on the lens to reduce the size and cost of the device.

Abstract: By using an offset parabolic concave mirror as a concave mirror, and arranging a lens having an entrance pupil at the geometric focal point of the offset parabolic concave mirror, a group of rays incident parallel to the optical axis of the offset parabolic concave mirror become chief rays which are telecentric with respect to an object plane orthogonal to the optical axis of the offset parabolic concave mirror, and diverging light from each object point on the object plane can be detected on a quadric image plane formed by the lens at the focal point of the offset parabolic concave mirror without blind spots. An image of the target object is detected after the beams reflected by the offset parabolic concave mirror are bent by the reflecting mirrors and made incident on the lens to reduce the size and cost of the device.

Abstract: A spectroscope device is provided to maintain the uniformity of the central transmitting wavelength in the field of view and to minimize the broaden of the bandwidth of the transmitting wavelengths in an optical lens using an optical tunable filter (variable wavelength filter), even with a wide field of view and/or a large numerical aperture. A space is defined in which, when each beam that is incident from each off-axial object point on the object surface toward the optical lens that includes a plurality of lens elements between an object surface and a conjugate real image surface reaches the optical tunable filter, the chief ray is maintained parallel to the optical axis. Therefore, if an optical tunable filter is disposed in this space, each beam is always incident normal to the filter, so only the narrow band components at the specific central wavelength can be transmitted.

Abstract: A spectroscope device is provided to maintain the uniformity of the central transmitting wavelength in the field of view and to minimize the broaden of the bandwidth of the transmitting wavelengths in an optical lens using an optical tunable filter (variable wavelength filter), even with a wide field of view and/or a large numerical aperture. A space is defined in which, when each beam that is incident from each off-axial object point on the object surface toward the optical lens that includes a plurality of lens elements between an object surface and a conjugate real image surface reaches the optical tunable filter, the chief ray is maintained parallel to the optical axis. Therefore, if an optical tunable filter is disposed in this space, each beam is always incident normal to the filter, so only the narrow band components at the specific central wavelength can be transmitted.

Abstract: In an incoming path, light fed to an input port is demultiplexed by a wavelength demultiplexer in terms of wavelength, converged by a first light-converging optical system, reflected by a first reflecting mirror, turned into parallel light by the first light-converging optical system, and multiplexed by the wavelength demultiplexer, so as to be fed to a reflecting surface of a rectangular reflecting mirror. In an outgoing path, the light reflected by the rectangular reflecting mirror is demultiplexed by the wavelength demultiplexer in terms of wavelengths, converged by the first light-converging optical system, reflected by the first reflecting mirror, turned into parallel light by the first light-converging optical system, and multiplexed by the wavelength demultiplexer, so as to be fed to an output port. An image of each wavelength light component reflected by the first reflecting mirror is inverted between the incoming and outgoing paths.

Abstract: In an incoming path, light fed to an input port is demultiplexed by a wavelength demultiplexer in terms of wavelength, converged by a first light-converging optical system, reflected by a first reflecting mirror, turned into parallel light by the first light-converging optical system, and multiplexed by the wavelength demultiplexer, so as to be fed to a reflecting surface of a rectangular reflecting mirror. In an outgoing path, the light reflected by the rectangular reflecting mirror is demlutiplexed by the wavelength demultiplexer in terms of wavelengths, converged by the first light-converging optical system, reflected by the first reflecting mirror, turned into parallel light by the first light-converging optical system, and multiplexed by the wavelength demultiplexer, so as to be fed to an output port. An image of each wavelength light component reflected by the first reflecting mirror is inverted between the incoming and outgoing paths.

Abstract: Disclosed is a laser apparatus having an optical pumping source, first and second resonator mirrors, a laser medium provided on a light route between the first and second resonator mirrors, an optical system provided in a light route between the laser medium and the second resonator mirror; and a nonlinear optical crystal for generating through wavelength conversion a higher harmonic wave(s) from a fundamental wave of laser generated by the laser medium. The nonlinear optical crystal is capable of being inserted between the intermediate optical system and the second resonator mirror. The second resonator mirror is a concave mirror. The intermediate optical system is constituted by a single concave mirror reflecting the fundamental wave and transmitting the higher harmonic wave(s).

Abstract: A reversible valve for reversible refrigeration cycle. The valve means used therein is a hollow cylindrical body longitudinally extending within the valve body. It has a pair of inclined annular walls projecting from around the hollow cylindrical body to define an annular chamber therearound in cooperation with the valve body such that the annular chamber communicates the suction tube selectively with either one of said pair of tubes.

Abstract: A four-way valve for reversible refrigeration cycle. It comprises a casing, a delivery tube in communication with a compressor and opening into the casing, a suction tube in communication with the compressor and opening into the casing, a pair of tubes in communication with two heat exchangers respectively, and opening into the casing one on each side of the suction tube, valve means for communicating the suction tube selectively with either one of the pair of tubes; and a two-way pilot valve mounted longitudinally to the casing. The two-way valve longitudinally mounted to the valve body of the reversible valve permits its vertical installment, thus remarkably reducing horizontal space required therefor.