| 摘要 |
An optical reading device is disclosed which comprises: a light emitting element for emitting light to irradiate a medium; a light receiving element for carrying out the light-electro conversion of the reflected light from the said medium which is irradiated from the light emitting element; a light receiving side lens for focussing the light reflected from the medium onto the light receiving element and having an optical axis aligned with the optical axis of the light receiving element; and a light emitting side lens having a larger numerical aperture than that of the said light receiving side lens, and for focussing the light from the said light emitting element onto the said medium, and also having an optical axis deviatingly disposed from the optical axis of the light receiving element; characterized in that the optical axis of the light emitting side lens is disposed within the focal zone on the detection surface of the medium, that is, within the focal zone of the light coming from the light emitting element through the light emitting side lens. The optical reading device thus constituted will not be influenced much by the forward reflection of light, the setting range of the resolving power will be made free, the focal depth will become deeper, and the reading probability will be improved.
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