Abstract:
A high sensitivity solid-state imaging device applicable even to an optical system of short focal length (large incident angle ?). Each element (size?2.8 mm) comprises a distributed refractive index lens (1), a color filter (2) for G, Al wiring (3), a signal transmitting section (4), a planarization layer (5), a light receiving element (Si photodiode) (6), and an Si substrate (7). A concentric circular structure of the distributed refractive index lens is composed of four kinds of material of different refractive index, i.e. TiO 2 (n=2.53), SiN(n=2.53), SiO 2 (n=2.53) and air(n=1.0), wherein the difference of radius of outer circumference between adjacent circular light transmitting films is 100nm. The film thickness is 0.4µm.
Abstract:
In an optical head operable to record to and read from an optical recording medium, a beam emitted by a light-emitting element is reflected toward the light-emitting element by a first reflective mirror, and this reflected beam is reflected toward the optical recording medium by a second reflective mirror and focused on a recording surface of the optical recording medium. In this case, the first reflective mirror blocks a principal ray of the beam traveling toward the optical recording medium from the second reflective mirror, and the second reflective mirror consists of a plurality of concentric annular mirrors centered on the principal ray of the beam and separated from each other by a predetermined interval.