Abstract: The optical scanner of this invention includes a light source, an optical deflector for scanning a light flux from the light source, a first image formation optical system disposed between the light source and the optical deflector, and a second image formation optical system disposed between the optical deflector and a surface to be scanned. The second image formation optical system includes a curved mirror for reflecting a light flux from the optical deflector and a correction lens for converging the light flux from the curved mirror on the surface to be scanned. A refractive power in the sub-scanning direction at the center of the correction lens in the scanning direction is different from that at the periphery thereof.

Abstract: The present invention provides a method of designing a post-objective type optical scanner having an optical deflector composed of cylindrical or spherical reflecting surfaces for deflecting a converged light beam from a condensing lens by reflecting the converged light beam as it rotates, and a compensating lens located in an optical path between the optical deflector and a scanning surface for converging the deflected light beam from the optical deflector to a point on the scanning surface, of which power in the sub-scanning direction varies with a length from the center thereof in the scanning direction.

Abstract: An anamorphic single lens has its radii in respective directions determined by the transfer efficiency of beams and imaging positions in respective directions, as required by the overall optical scanner. The anamorphic single lens satisfies the following formulae: ##EQU1## where fm is the focal length of the lens in the direction of beams diverged at a larger angle, TH is the thickness, S is the distance from a light source side principal point position (6) to the light source (5) in the direction of the beams diverged at the larger angle, and S' is the distance from a light source side principal point position (8) to the light source in the direction of beams diverged at a smaller angle.

Abstract: In an infrared wide-angle single lens which is as constructed as of a positive meniscus lens, the following conditional expressions (1) through (6) are satisfied:(1) -50.0 th<r.sub.1 <-3.5 th(2) -5 th<r.sub.2 <-1.1 th(3) 2<n<4.5(4) 0.1 f<d<0.8 f(5) 0.5 f<bf<1.5 f(6) 0.5 f<th<2fwhere, an aperture stop is disposed between an object plane and a first surface, d is the distance between the aperture stop and the first surface, th is the lens thickness, bf is the backfocus, r.sub.1 is the radius of curvature of the first surface of the lens, r.sub.2 is the radius of curvature of a second surface of the lens, n is the refractive index of a vitric material of the lens at a wavelength of 10 .mu.m, and f is the focal length.

Abstract: An apparatus for detecting position or temperature distribution of an object has a lens which is rotated around a pyroelectric type infrared sensor to collect incident infrared ray on the sensor while scanning the incident infrared ray in a rotational direction. The optical scanning is operated also in the longitudinal direction by providing with a plurality of lenses having different view in the longitudinal direction, the lenses being rotated sequentialy around the sensor. Further, detection of temperature of an object is conducted without using optical chopper by alternately observing the object and a standard temperature material which is arranged in a part of view, or by providing a stationary slit unit on a curved surface formed around a center axis which is the same as the rotation axis of the lens and a movable slit unit having the same pitch and arranged adjacent to the stationary slit unit and rotating together with the lens to intermitting the incident infrared ray.

Abstract: A post objective type optical scanner for having a light source for emitting a light beam having a first width in the scanning direction and a second width in the sub-scanning direction, a single lens having an incident surface and an emergent surface and including a scanning optical system having a first light source side principal point, and a sub-scanning optical system having a second light source side principal point, for converting a light beam emitted from the light source having a scanningwise width and a subscanningwise width, the scanning optical system converting the first width of the light beam into the scanningwise of the scanning beam while the sub-scanning optical system converting the second width of the light beam into the subscanningwise width of the scanning beam. The distance of the first light source side principal point from the light source is greater than the distance of the second light source side principal point from the light source.

Abstract: A post-objective type optical scanner in which optical flux is converted to condensed light or diffused light by a lens and then scanned on a scanning surface by an optical deflector is constituted by a light source, an optical scanner for leading the flux of light from the light source to an optical deflector and an optical deflector which has a toric deflecting surface in which the radius in the scanning direction is convex and the radius in the sub-scanning direction is concave, and which compensates the curvatures of field in both scanning and sub-scanning directions and scans the optical flux by rotation.

Abstract: A high-resolution post-objective type optical scanner in which a beam of light is scanned by an optical deflector onto a scanning surface after it is converged by a condensing lens, the light beam converged on the scanning surface having a spot size with an intensity of 1/e.sup.2 and not exceeding 80 .mu.m over the entire area of the scanning surface. The optical deflector includes a reflecting surface composed of a cylindrical surface or a spherical surface. A compensating lens disposed between the optical deflector and the scanning surface has a power which varies in the scanning direction between a central portion and a peripheral portion of the compensating lens. The distance r between an axis of rotation of the optical deflector and a deflecting point, the distance L between the deflecting point and the scanning surface, and an effective scanning width Y.sub.O are related by the relationship r.gtoreq.-0.025.times.L+0.1.times.Y.sub.o +1.4.