The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 30, 2013
Filed:
Aug. 04, 2009
Taiki Sawabe, Ota-ku, JP;
Taiki Sawabe, Ota-ku, JP;
Disco Corporation, Tokyo, JP;
Abstract
A laser beam having an annular spot shape with which a workpiece is irradiated is reflected on an upper surface and a lower surface of the workpiece. The reflected light having the annular spot shape which is reflected on the lower surface of the workpiece is intercepted by a pinhole mask, whereas the reflected light having the annular spot shape which is reflected on the upper surface of the workpiece is permitted to pass through the pinhole mask, and the intensity of light received is detected based on the latter reflected light. Therefore, the height position of the upper surface of a workpiece can be detected even where the workpiece is transmissive to visible rays. In this case, with regard to the reflected light having the annular spot shape which is reflected on the upper surface of the workpiece, the intensity of the light after diffusion by a laser beam diffusing unit is detected by a photodetector having a detecting surface with a predetermined area. This makes it possible to assuredly and accurately detect the upper surface height position of the workpiece, even in the presence of scattering of the annular spot shape.