US 5,309,422 A · Light separation element and light receiving optical device using same

Abstract

A light separating element designed to have parallel first and second external surfaces, a first polarizing film disposed on the first external surface and arranged to reflect a first portion of a first component in a first direction and transmit a second portion of the first component and all of a second component in a second direction. Further, a second polarizing film can be disposed on a second external surface which reflects a first portion of the second component in a third direction and transmits a second portion of the first and second components in a fourth direction. Further, the first portion of the second component is reflected by the second polarizing film to strike the first polarizing film. The first polarizing film transmitting a first portion of the second component in a fifth direction or a reflecting surface disposed on the second external surface and arranged to reflect a second portion of a first component and all of a second component in a third direction toward the polarizing film. The first portion of the second component is transmitted by the polarizing film in a fourth direction and a second portion of the second component and the second portion of the first component are reflected in a fifth direction toward the reflective surface. The second portions of the first and second components traveling in the fifth direction are reflected by the reflective surface in a sixth direction toward the polarizing film and the second portions of the first and second components traveling in the sixth direction are transmitted by the polarizing film in a seventh direction.

Claims12

Dependent claims

A light separation element positioned in a path of light having first and second polarized components angularly spaced 90 degrees from each other in a rotating direction with respect to an optical axis, wherein a pair of polarizing films each transmitting said first polarized component at a predetermined rate therethrough and transmitting said second polarized component at a predetermined rate therethrough are arranged in parallel to each other on opposite surfaces of said light separation element, but inclined at an angle with respect to said optical axis, and an optical member for rotating the polarizing plane of light passing therethrough 90 degrees is disposed between said pair of polarizing films.

An optical device for reading an optical disk, said optical device having a light source for emitting light which is reflected from the optical disk, the reflected light traveling along an optical axis and having a first component and a second component orientated 90.degree. from said first component with respect to said optical axis;

said optical device comprising:
a light separating element comprising:
parallel first and second external surfaces positioned such that said reflected light strikes said first external surface at an angle with respect to said optical axis,
a first polarizing film disposed on said first external surface and arranged to reflect a first portion of said first component in a first direction and transmit a second portion of said first component and all of said second component in a second direction, and
a second polarizing film disposed on said second external surface and arranged to reflect a first portion of said second component in a third direction and transmit second portions of said first and second components in a fourth direction,
wherein said first portion of said second component is reflected by said second polarizing film to strike said first polarizing film, said first polarizing film transmitting said first portion of said second component in a fifth direction.

3 more elements

An optical device for reading an optical disk, said optical device having a light source emitting light which is reflected from the optical disk, the reflected light traveling along an optical axis and having a first component and a second component orientated 90.degree. from said first component with respect to said optical axis;

said optical device comprising:
a light separating element comprising:
parallel first and second external surfaces positioned such that said reflected light strikes said first external surface at an angle with respect to said optical axis,
a polarizing film disposed on said first external surface and arranged to reflect a first portion of said first component in a first direction and transmit a second portion of said first component and all of said second component in a second direction, and
a reflecting surface disposed on said second external surface and arranged to reflect said second portion of said first component and all of said second component in a third direction toward said polarizing film,
wherein a first portion of said second component is transmitted by said polarizing film in a fourth direction and a second portion of said second component and said second portion of said first component are reflected in a fifth direction toward said reflective surface,
wherein said second portions of said first and second components traveling in said fifth direction are reflected by said reflective surface in a sixth direction toward said polarizing film, and
wherein said second portions of said first and second components traveling is said sixth direction are transmitted by said polarizing film in an seventh direction.

5 more elements

Dependencies are inferred from the claim text.

Light separation element and light receiving optical device using same

Life of this patent

Light separation element and light receiving optical device using same

Life of this patent

Abstract

Claims12