Abstract: A method for manufacturing a glass substrate for an information recording medium, wherein the abrasive and foreign matters adhered on the glass substrate after the polishing step are surely removed without making the cleaning step complicated. The glass substrate is cleaned by scrubbing with water to which 0.5-5.0 mass % of hydrogen peroxide has been added as a cleaning solution.

Abstract: An optical recording medium including a substrate, an information recording region arranged on the substrate and capable of bearing information being readable with predetermined light, and a tracking region arranged on the substrate, having optical characteristics different from those of the information recording region and having substantially no difference in level with respect to the surface of the information recording region. A method of making an optical recording medium, including the steps of forming uniformly a recording layer on a substrate, the recording layer being made of a recording material being reversibly reactive to predetermined light, and causing an irreversible reaction in a partial region of the recording layer without causing a substantial difference in level with respect to the other region of the recording layer.

Abstract: A system and method of visually inspecting a transparent body and a translucent body comprises applying light to a reverse surface of an object to be inspected by a transmission light source, and applying light, at a low angle, to at least one of an obverse surface and the reverse surface of the object to be inspected by a reflection light source. Concave defects and adherents of the object to be inspected are detected by use of transmitted light emitted from the transmission light source, and adherents of the object to be inspected are detected by use of reflected scattered light emitted from the reflection light source.

Abstract: A solid immersion lens has a positioning surface and a surface including a convex surface forming an effective optical path. The solid immersion lens has a hemispherical or hyperhemispherical shape provided with a convex surface on the light entering side and an approximate plane surface on the light exiting side.

Abstract: An method and device for inspecting for surface defects, internal defects, and surface-adhered foreign matter on semitransparent materials. An illuminating device transmits light, that is then collimated through a collimating lens unit, through an object to be inspected. The light then transmits through the object to be inspected an eventually is detected by a detector. Any defects in the object to be inspected will be detected.

Abstract: A glass gob production device for producing a glass gob from molten glass. The glass gob production device has a crucible which accommodates molten glass, a nozzle one end of which is connected to the crucible and from the other end of which the molten glass in the crucible is discharged, and a support member opposite to the other end of nozzle and having an indentation on the surface thereof for receiving and retaining the discharged molten glass in the indentation to form a glass gob. The indentation of the support member has a bottom surface and a reference surface extending in a direction perpendicular to the circumference of the bottom surface.

Abstract: An interferometer utilizing interference whose object is the measurement of the configuration of a test surface with high precision by allowing accurate positioning to a predetermined measuring position for the measurement of the configuration of the test surface.The interferometer is equipped with an alignment pattern (4A) which generates a wave front that converges at the predetermined measuring position, as well as a wave front for measuring the configuration corresponding to the design configuration of the test surface (9), and by using a test surface-reflected beam of the wave front generated by the alignment pattern, an alignment observation optical system (8) measures the displacement of the test surface from the predetermined measuring position.