Canon Kabushiki Kaisha

Kyowa Electric and Chemical Co., Ltd.

Susumu Seto

Mitsuhiro Tokuhara

Yu Yamada

Yukio Takemura

Takeshi Kuwayama

Kashichi Hirota

Junji Fukuda

Akihiko Toriumi

There is disclosed a Fresnel lens, adapted to be placed in front of a display screen of a computer or a television set in order to magnify images for observation, which does not cause a rainbow-like pattern to appear even when annular prism elements as the constituent elements of said Fresnel lens are arranged at a fine pitch. A spherical surface having a radius of curvature corresponding to the focal distance of the lens formed by said annular prism elements of said Fresnel lens is formed within a circular area defined by a predetermined radius around the optical axis, where the rainbow-like pattern would otherwise appear due to diffraction. The predetermined pitch in arranging a plurality of annular prism elements of the Fresnel lens is equal to or less than 0.25 mm and the height of the annular prism elements in the circular area is equal to or less than 5 &mgr;m and preferably equal to or less than 7 &mgr;m.

Image magnifying Fresnel lens for observation of a on display screen

An image detecting device includes a lens system for imaging a given surface area of an object on the light-receiving surface of a photoreceptor such as a photosensitive drum, a solid state pickup element or the like, said lens system including at least one single lens for absorbing light in a wavelength range having high sensitivity from an optical system containing said photoreceptor, said lens system being adapted to compensate said optical system in color sensitivity.

Image detecting device

A projection apparatus includes an optical system for forming an image of an object illuminated by an illumination source on a photosensitive member. In the projection apparatus according to the invention, at least one lens in the lens system disposed in the optical path extending from the illumination source to the photosensitive member is such lens which possesses a property of spectral transmission factor to compensate the spectral sensitivity of the photosensitive member.

Projection apparatus which compensates for the spectral sensitivity of

This specification discloses a scanning illuminating device in a copying apparatus of the slit exposure type in which a movable slit area of an original is projected upon a movable photosensitive medium by a projection lens. The device is characterized in that light sources are fixed to the opposite end portions of the original surface with respect to the scanning direction, the magnification of the light source image becomes gradually greater at one end of the scanning direction and gradually smaller at the other end of the scanning direction, and imaging elements are moved in the scanning direction so that the illumination distribution on the original surface is formed so as to compensate for the loss of quantity of light of the projection lens due to the so-called cos biquadratic rule or the like to thereby enable copying of uniform density in the scanning direction.

Scanning illuminating device

A scanning illuminator has a compact structure suitable for use in high speed copying machines and is adapted to reflect light beams from two light sources fixed adjacent to the opposite ends of an original supporting area to the surface of an original by means of rotary mirrors and translating mirrors for illuminating the original surface in a slit shape. The scanning illuminator has a flexibility in optical adjustment.

Scanning illuminator

A scanning illuminator suitable for use in high speed copying machines is adapted to compensate the distribution of loss in light quantity with respect to an imaging lens due to the so-called Cos.sup.4 law in the scanning direction and includes fixed sources of light. The scanning illuminator is characterized by illuminating systems disposed symmetrically relative to an original supporting area, each illuminating system being adapted for illuminating the opposite end areas of an original by a portion of light beam from the fixed source of light adjacent one end of the original, especially the light beam portion emitted and bled backward of the light source, the illuminating system having at least one rotating or translating scan mirror for scanning the illuminating light beam.

Growing community of inventors

Odawara, Japan

Susumu Seto