Abstract: A photomask defect inspection method is provided by which defects of pin holes with the diameter equal to or less than 0.35 .mu.m can be detected with certainty. According to the inspection method, a pattern whose image is projected onto an imaging position by the use of illumination light (P1) for exposure consists of light transmitting portions (41) formed on a glass base (2) and light intercepting portions (42) which transmit part of the illumination light (P1) in such a way that a phase of the part of the illumination light (P1) passing through the light intercepting portions (42) is delayed with respect to a phase of the illumination light (P1) passing through the light transmitting portions (41).

Abstract: The present invention provides a method for altering the light traveling distance in an optical scanning module using transparent glass. The optical scanning module comprises a transparent glass module that refracts light to alter the traveling distance of the light as it passes from the document to the optical sensing device. The proper thickness of this transparent glass module is specifically chosen to correctly calibrate the error of the traveling distance of the light created during the manufacturing of the scanner.

Abstract: The surface groove 26c formed in the circumferential direction has a configuration 26x producing a shallow groove. Thus, relative rotation during lens attachment is accomplished without obstruction, and the strength of the bayonet pawls is improved by the enhanced thickness of the center portion by the formation of a gradual angle formation toward the exterior side of cylinder wall 20 from both ends of the surface groove toward the center portion thereof. This type of surface groove configuration 26x is formed at the three surface grooves 26a, 26b, 26c.