Abstract: A scanning apparatus for obtaining plural scanning beams, wherein plural stationary light beams are incident upon a deflecting reflection surface in different directions, but they are superposed with each other on the reflection surface. Plural scanning beams are provided from the deflecting reflection surface. Since the plural beams are superposed on the reflection surface, the center of deflection is the same for all of the light beams, so that the scanning beams are easily processed by a single optical system.

Abstract: This invention relates to a photo-electrical detecting apparatus for forming a dark-field image of an object on a one-dimensional image sensor and reading said image photo-electrically. The apparatus includes a telecentric objective lens, and a light source image is formed on the clear aperture plane of said lens, said image being in focus in a direction on said plane and out of focus in a perpendicular direction. A line- or band-shaped area of the object is illuminated by the light from said light source image. Thus a dark-field image of the object is formed on said one-dimensional image sensor by providing, on a plane equivalent to said aperture plane, a filter which intercepts the normal reflected light from said object and transmits the scattered light therefrom.

Abstract: A photoelectric detecting device in which a photoelectric detecting system for scanning a surface to be inspected by a light beam and for receiving the light from the inspected surface by a photoelectric detector is partly common to an observation optical system for illuminating the inspected surface with an illuminating light and for observing the inspected surface. The device has a dichroic mirror and a polarizing beam splitter, whereby photoelectric detection is effected without loss of light and without adverse effect of the illuminating light.

Abstract: An improved photoelectric detecting apparatus is disclosed in which a subject surface containing a pattern which diffracts light in a predetermined direction is scanned with spotlight and the diffracted light coming from the pattern is detected by means of photoelectric element so as to read out information of the pattern. The apparatus comprises a first photoelectric element for detecting the light diffracted in the predetermined direction, a second photoelectric element adapted for detecting light diffracted in directions other than the predetermined direction and an operational circuit for operating the signal derived from the first photoelectric element and that derived from the second one. Thus, when there is any diffractive matter such as flaw, dust and the like on the subject surface, diffracted light from the diffractive matter is detected by both the first and second photoelectric elements whereas diffracted light from the pattern is detected only by the first photoelectric element.

Abstract: Disclosed in this specification is a scanning device which scans an object having a flat reflection surface and an inclined reflection surface with an inclination relative to the flat reflection surface such as, for example, a mask and a wafer to be used in manufacturing IC, LSI, etc., with light beam, and detects only the reflected light from the inclined reflection surface with a light detector. In order to make it possible to detect only the reflected light from the inclined reflection surface with the light detector, a telecentric lens is used as the scanning lens in this scanning device, and the original point of deflection of the above-mentioned light beam coincides with the center of the pupil of this telecentric lens. In addition, a filter is disposed on the pupil surface to intercept light from the flat reflection surface.

Abstract: This invention provides an optical device for detecting the position of a second mark relative to a first mark by optically scanning the first and second marks on a scanning surface. The first and second marks are scanned by a scanning spot light and the reflecting lights from the first and second marks are detected by a photoelectric detector. The relative positions of the first and second marks are computed on the basis of the detected signals.

Abstract: Disclosed in this specification is a scanning device which scans an object having a flat reflection surface and an inclined reflection surface with an inclination relative to the flat reflection surface such as, for example, a mask and a wafer to be used in manufacturing IC, LSI, etc., with light beam, and detects only the reflected light from the inclined reflection surface with a light detector. In order to make it possible to detect only the reflected light from the inclined reflection surface with the light detector, a telecentric objective lens is used as the scanning lens in this scanning device, and the original point of deflection of the above-mentioned scanning light beam coincides with the center of the pupil of this telecentric objective lens. In addition, a filter is disposed on the pupil surface to intercept light from the flat reflection surface. An optical system between the scanning device and the object is of f-.theta.