Asahi Kogaku Kogyo Kabushiki Kaisha

Yuka Adachi

Takashi Iizuka

Yoshiyuki Kobayashi

Mikio Horie

A scanning-type image reading device is provided which includes an image sensor, a rotating-type scanning system, a focusing mechanism, and a controller. The controller may control the focusing mechanism for each rotational position of the rotating-type scanning system. In a particular case, the controller may control the focusing mechanism according to the rotational position of the rotating-type scanning system and according to an initial position of the focusing mechanism determined at a predetermined position of the rotating-type scanning system.

Scanning-type image reading device

Disclosed is a reading lens consisting of one glass lens and first and second plastic lenses. A positive diffraction lens structure being is formed on one surface of the surfaces of the first and second plastic lenses. The positive diffraction lens structure functions at least to compensate a longitudinal chromatic aberration which is caused by refractive power of the glass lens and the first and second plastic lenses.

Reading lens

An achromatic lens system comprising a front lens group, a diffraction lens and a rear lens group, in this order from the object side, wherein; the front lens group is provided with a frontmost convex surface on the object side and a rearmost concave surface on the image side; the rear lens group is provided with a rearmost convex surface on the image side; the front and rear lens groups are arranged to generate under-axial chromatic aberration for blue light and generate over-axial chromatic aberration for red light, with respect to green light that is considered the reference light; and, achromatic correction of light in the visible region is conducted by correcting the axial chromatic aberrations with a diffracting function of the diffraction lens.

Growing community of inventors

Aichi-ken, Japan

Yuka Adachi