Nippondenso Co., Ltd.

Hirosi Ando

Yoshiaki Hoashi

Akira Kurahashi

Toshiyuki Kaneiwa

Masayuki Goto

Shinji Namba

Optical radar apparatus

A hologram plate manufacturing apparatus comprising a copying optical element disposed in opposed relation to a photosensitive surface of a hologram plate. The copying optical element is arranged so that its one surface facing the photosensitive surface of the hologram plate has a plane configuration and its other surface has a convex or concave configuration. On the convex or concave surface there is formed a reflection film for effectively reflecting incident light. Also included a refraction index adjusting layer which is provided between the photosensitive surface of the hologram plate and the convex or concave surface of the copying optical element, the refraction index adjusting layer having an index of refraction substantially equal to indexes of refraction of the hologram plate and the copying optical element. Further, a prism is disposed in opposed relation to the incident surface of the hologram plate and arranged such that light incident on the incident surface of the hologram plate and reflected on the reflection film is not re-reflected on the incident surface of the hologram plate so as not to be directed toward the hologram plate. This arrangement can suppress generation of noise images due to unnecessary reflection.

Method and apparatus for copying and manufacturing hologram plate

A light-guiding device having a light-incident surface and a light-outgoing surface for guiding light incident from the light-incident surface from the light-outgoing surface toward a light-receiving surface of a photodetector for generating an electric signal corresponding to a quantity of the received light. The device comprises a hologram layer having an interference pattern which acts as a diffraction grating to diffract and reflect the light, incident from the light-incident surface, in a predetermined direction. The hologram layer is interposed between first and second total reflection layers. The first total reflection layer has a first total reflection surface disposed in opposed relation to one of the longitudinal surfaces of the hologram layer so that the light diffracted and reflected by the hologram layer is incident on the first total reflection surface at a predetermined angle larger than the critical angle so as to be total-reflected thereon, and the second total reflection layer has a second total reflection surface disposed in opposed relation to the other longitudinal surface of the hologram layer so that the incident light passing through the hologram layer is incident on the second total reflection surface at a predetermined angle greater than the critical angle so as to be total-reflected thereon. This arrangement improves the light-receiving performance concurrently with reducing the thickness of the device.

Light-guiding device having a hologram layer

Growing community of inventors

Nishikasugai, Japan

Hirosi Ando