Abstract: Disclosed is a distance measuring device using an optical comb. In order for the absolute distance to an object to be measured which has a surface with low reflection ratio or a scattering surface and is approximately 10 m apart, to be easily measured with accuracy of 0.1 mm or more using an optical and contactless method, the distance measuring device which measures the distance to the object to be measured is configured such that the distance to the object to be measured is measured by comparing the phase of the beat signal between a light source and a plurality of CW lasers which are reflected or scattered by the object with the phase of the beat signal between the light source and a plurality of CW lasers prior to being irradiated onto the object.

Abstract: Disclosed is a distance measuring device using an optical comb. In order for the absolute distance to an object to be measured which has a surface with low reflection ratio or a scattering surface and is approximately 10 m apart, to be easily measured with accuracy of 0.1 mm or more using an optical and contactless method, the distance measuring device which measures the distance to the object to be measured is configured such that the distance to the object to be measured is measured by comparing the phase of the beat signal between a light source and a plurality of CW lasers which are reflected or scattered by the object with the phase of the beat signal between the light source and a plurality of CW lasers prior to being irradiated onto the object.

Abstract: The invention has a function of preparing a data base for a relation between a defect shape and an arrangement for the optical system capable of detecting the shape at high sensitivity and automatically adjusting the arrangement for the optical system. As the method of preparing the data base, a method of using optical simulation or an experimental method of using a sample having an optical shape is applied. A pinhole position and a beam size are adjusted automatically so as to attain the optimal arrangement for the optical system to an inputted defect shape based on the data base.

Abstract: There is provided a defect inspecting apparatus, which includes an irradiating optical system of irradiating a light beam on a surface of a face plate of a disk mounted on a stage to scan the surface of the face plate, a light-receiving optical system of receiving specular reflection light that has transmitted a shading filter with a shading difference that changes an amount of the specular reflection light from the face plate resulting from the light beam irradiated on the disk, and a processing unit of identifying defects on the surface of the face plate from the change in amount of the specular reflection light that has transmitted a filter, so that a size and a height of the defect can be measured with high accuracy when irregular defects are determined, which is not easily achieved by a conventional lens effect.

Abstract: The present invention relates to an apparatus for detecting defects on a disk surface which projects light on the disk surface by a light transmitting system, receives specula reflection light and scattered light by a light receiving system, exposes defects by performing a two-dimensional frequency filter process on a signal, and performs a defect determination process to extract a linear-shaped isolative defect candidate. Next, the present invention performs a periodicity determination process to classify and detect the periodically generated linear and circular arc defects and the isolatively generated linear and circular arc defects.

Abstract: The invention has a function of preparing a data base for a relation between a defect shape and an arrangement for the optical system capable of detecting the shape at high sensitivity and automatically adjusting the arrangement for the optical system. As the method of preparing the data base, a method of using optical simulation or an experimental method of using a sample having an optical shape is applied. A pinhole position and a beam size are adjusted automatically so as to attain the optimal arrangement for the optical system to an inputted defect shape based on the data base.

Abstract: There is provided a defect inspecting apparatus, which includes an irradiating optical system of irradiating a light beam on a surface of a face plate of a disk mounted on a stage to scan the surface of the face plate, a light-receiving optical system of receiving specular reflection light that has transmitted a shading filter with a shading difference that changes an amount of the specular reflection light from the face plate resulting from the light beam irradiated on the disk, and a processing unit of identifying defects on the surface of the face plate from the change in amount of the specular reflection light that has transmitted a filter, so that a size and a height of the defect can be measured with high accuracy when irregular defects are determined, which is not easily achieved by a conventional lens effect.

Abstract: The present invention relates to an apparatus for detecting defects on a disk surface which projects light on the disk surface by a light transmitting system, receives specula reflection light and scattered light by a light receiving system, exposes defects by performing a two-dimensional frequency filter process on a signal, and performs a defect determination process to extract a linear-shaped isolative defect candidate. Next, the present invention performs a periodicity determination process to classify and detect the periodically generated linear and circular arc defects and the isolatively generated linear and circular arc defects.