Patent Number: 6,310,689

Title: Pattern reading apparatus

Abstract: A pattern reading apparatus for reading a pattern from a reflective object or a transparent object. The pattern reading apparatus includes a minute-area light source, an objective lens system, an imaging lens, and an imaging element. The objective lens system causes the illumination light beam from the light source to be incident on the object and converges the light beam reflected from or transmitted through the object. The imaging lens forms an image of the object using only a scattered component of light which has been reflected from or which has passed through the object. The imaging element is disposed at a position where the image of the pattern is imaged for reading the pattern. In particular, light that forms an image of the light source is prevented from reaching the imaging element. In the case of a reflective object, ghosting light due to a reflection from a surface of the objective lens is prevented from reaching the imaging element.

Inventors: Ishikawa; Tuyoshi (Tokyo, JP), Otsuka; Kenichiro (Tokyo, JP), Ando; Hiroaki (Tokyo, JP)

Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha

International Classification: G02B 27/02 (20060101); G03F 7/20 (20060101); G01N 021/47 ()

Expiration Date: 10/30/2018