Abstract: An interval detection method for detecting the interval between two marks provided on the surface of a wafer with high accuracy using other two marks provided on the wafer, and a method for detecting the relative positions of a wafer and a mask with high accuracy are provided.

Abstract: A method of detecting a relative positional deviation of a first object having a first grating mark with an optical power and a second object having a second grating mark with an optical power, is disclosed, wherein a projected radiation beam is diffracted by the first and second grating marks in sequence and, on the basis of a position of convergence on a light receiving surface of plural diffraction beams produced by the diffraction through the first and second grating marks and including a signal beam having been diffracted at a predetermined order by each of the first and second grating marks, the relative positional deviation is determined, a detection zone is defined on the light receiving surface, the signal beam is converged upon the detection zone, and a predetermined diffraction beam of the plural diffraction beams which, for a relative positional deviation of the first and second objects, shows displacement different from that of the signal beam is substantially prevented from being converged upon

Abstract: A position detecting system includes a light source for producing a light beam for irradiating a reference mark formed on an object which is relatively displaceable relative to the light beam, a detector for detecting a light quantity distribution of the light from the reference mark, and a circuit for comparing a first light quantity distribution at a first position with a second light quantity distribution at a second position spaced from the first position by a predetermined distance, and for determining a reference position of the object on the basis of the comparison.

Abstract: A method and apparatus for detecting a positional relationship between first and second objects is disclosed, which includes a light source for projecting light to the first and second objects, a photodetecting system for detecting light from one of the first and second objects irradiated with the light from the light source, the detecting system being operable to detect first light whose position of incidence upon a predetermined plane is dependent upon the positional relationship of the first and second objects in a direction along the interval therebetween and in a direction perpendicular to the interval, second light whose position of incidence upon the predetermined plane is dependent upon the positional relationship of the first and second objects in the direction of the interval therebetween, and third light whose position of incidence upon the predetermined plane is independent of the positional relationship of the first and second objects in both the direction of the interval and the direction perpen

Abstract: A numeral display device has a first board member provided with a first group of pattern electrodes arranged to define a plurality of digits, each forming a figure eight pattern, the digits being arranged in an upper row and a lower row wherein for each digit the segment for the decimal point is electrically connected with at least a segment in the figure eight pattern while the other segments in said figure eight pattern are connected to display particular information, a second board member placed in facing relationship with said first board member and provided with a second group of pattern electrodes arranged to define a plurality of digits each forming a figure eight shaped pattern, the digits being arranged in an upper row and a lower row wherein for each digit the segment for decimal point is connected with at least a segment in the figure eight pattern other than those corresponding to the segments connected with the decimal point segment in said first board member while the other numerical segments ar

Abstract: An electronic instrument with a non-volatile display comprises a drive control circuit for controlling the display, first and second clear means for respectively clearing the non-volatile display and the drive control circuit, and a single clear instruction generating circuit for generating a signal to actuate both first and second clear means. Thus the non-volatile display and the control circuit may be cleared simultaneously.

Abstract: A liquid crystal display device is disclosed which comprises a plurality of groups of segment electrodes formed on a first plate for energization to define digits each having a seven bar format, and a plurality of groups of digit electrode elements opposed to respective groups of the segment electrodes being formed on a second plate opposed to the first plate. The digit electrode elements are driven by respective driving elements which are in turn selected by a digit pulse generator. There are provided means for altering the polarity of the driving voltage generated from the output of the driving elements.