Abstract: A reflected light beam from a magneto-optic disk is reflected by a first and second reflective element toward a signal detecting system. The first reflective element reflects the reflected light from the magneto-optic disk and gives a phase difference into the light beam. The second reflective element reflects the reflected light by the first reflective element toward the signal detecting system, and gives a phase difference which has the same amount as the phase difference caused by the first reflective element, but with the inverse sign thereof.

Abstract: A signal detecting apparatus in an optical disc apparatus having an objective lens which converges light emitted from a light source onto an optical disc and a condenser lens which converges light reflected by the optical disc and transmitted through the objective lens includes first and second light receiving elements, each having a light receiving surface located before or behind a convergence point on which the light reflected from the optical disc is converged when the objective lens is in a focal position. Each of the light receiving surfaces are split into at least four light receiving areas.

Abstract: A polarization and birefringence measuring device has an optical source which causes a wide polarized light beam to impinge on a specimen. A photodetecting sensor having picture elements in two dimensions detects a light beam containing information about the specimen. A analyzer is situated in front of the photodetecting sensor and rotated to vary the amount of light which is transmitted. A frame memory memorizes the intensity of each picture element in the photodetecting sensor, and a computer determines the polarization state of parts of the specimen coresponding to the intensity of each picture element sampled. The computer samples the output of the photodetecting sensor when the rotation angle of the analyzer has reached a specified value, and this is memorized by the frame memory.

Abstract: An interferometer for measuring the degree of deformation of an object, wherein alignment detection is facilitated by producing a moire pattern. An image signal data for reference fringes is compounded with interference fringe data that has been used for alignment detection. In generating a moire pattern, the interference fringe image signal data is process using the reference fringe data as a filter, resulting in improvement in visibility of the moire pattern.

Abstract: A compound prism including a plurality of unit prisms which have reflective interfaces defined by outer and/or inner surfaces thereof and which are arranged so that light is reflected by an inner surface of the interface of one of the unit prisms and by an outer surface of the interface of another unit prism.

Abstract: A ghost image eliminating optical system in a transmission optical system including a plurality of transmission optical elements having boundary reflection surfaces, so that a ghost image can be formed by light reflected by at least two specific boundary reflection surfaces, wherein the specific boundary reflection surfaces are coated with at least two anti-reflection coatings having complementary reflection characteristics to eliminate the ghost image.

Abstract: The supercharger pressure control system includes a sensor for detecting the supercharger pressure of the engine and regulates the pressure through a variable geometry device or an exhaust bypass valve. The control for the pressure regulation is carried out by comparing the sensed supercharge pressure with a target value. Any difference determined by this comparison is accumulated by a computer as an error and a basic control value is determined based on the error. Alternatively, a predetermined basic control value for the engine intake air is corrected in accordance with the error and this control value or corrected value is used to control the operation of the supercharge pressure regulator. This causes the regulator to operate in a manner responsive to variations in performance of the engine or turbocharger, thus maintaining the supercharged pressure within a permissible range of a target value.

Abstract: An apparatus for controlling a turbocharger includes a compressor and a turbine coupled to the compressor and comprises a variable capacity device for varying the flow rate of an exhaust gas introduced into the turbine in the low speed state of an engine connected to the turbocharger, an exhaust gas bypass device bypassing the variable capacity device and the turbine to control the flow rate of the exhaust gas in the high speed state of the engine, and an overboost device for detecting the accelerating state of the engine and controlling the operation of the exhaust gas bypass device such that the exhaust gas bypass device reduces the flow rate of the exhaust gas introduced into the turbine only when the supercharging pressure has reached a predetermined pressure in the accelerating state of the engine.