Abstract: A projection optical apparatus comprises illuminating means providing for an illuminating light beam, a projection optical system including optical elements disposed across the illuminating light beam and having an imaging plane, and detecting mean including temperature sensor means provided on at least one of the optical elements and producing an output corresponding to the temperature of the one optical element.

Abstract: An optical apparatus for detecting the position of an object by projecting a light image onto the object through a transparent plate and detecting the reflected light from the object through the transparent plate is disclosed. The projection optical system includes a first objective lens for forming the light image. The optical axis of the projection is disposed inclined to the above-said transparent plate. The detection optical system includes a second objective lens for refocusing the light reflected from the object. The optical axis of the reflection light detection between the second object lens and the object is disposed inclined to the transparent plate. The apparatus further comprises plane parallel optical members mounted obliquely so as to cancel the asymmetric aberrations generated by the above-said transparent plate.

Abstract: An apparatus which comprises a collimating lens, light source means for selectively forming light sources in two positions on the optical axis of the collimating lens, means for defining the position of the lens to be inspected opposite to the light source with respect to the collimating lens, a mask plate having translucent or opaque areas symmetrical to the optical axis, a relay lens for placing the mask plate at a position conjugate with the lens position, an imaging lens positioned opposite to the mask plate with respect to the relay lens, and photoelectric converting means for producing image signals corresponding to the positions, in a plane perpendicular to the optical axis, of the image of the translucent or opaque areas of the mask plate formed by the imaging lens.

Abstract: A current supply circuit for a telephone exchange is disclosed in which a current-supplying current amplifier series-connected between a power supply and a load amplifys an output current of an input current supply circuit, and a driving current amplifier for driving the current-supplying current amplifier is controlled by an output of an output voltage detector parallel-connected with the load in a negative-feedback fashion to set the differential mode output impedance of the current supply circuit at a large or small value in accordance with frequency and to set the common mode output impedance at a small value; and in which a part of the output voltage detector for connecting the load to the driving current amplifier includes a diode for preventing a direct current from flowing in a opposite direction to that of a direct current from the power supply in order to suppress, independently of the state of the load, a current which flows from the load side into the driving current amplifier, whereby an increase