Recursive-reflective photoelectric sensor
First Claim
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1. A recursive-reflective photoelectric sensor comprising:
- a sensor main body including a light projecting part that projects first circularly polarized light and a light receiving part that selectively receives, when a mixture of the first circularly polarized light and second circularly polarized light which is differently polarized from said first circularly polarized light is incident thereto, said second circularly polarized light; and
a recursive reflecting part that reflects said first circularly polarized light by converting into reflected light that includes said second circularly polarized light;
wherein said sensor main body includes;
a light projecting element;
a light receiving element;
a first phase-shift plate that converts first linearly polarized light into said first circularly polarized light and said second circularly polarized light into said first linearly polarized light; and
a first polarization filter that is placed between said light receiving element and said first phase-shift plate on a optical path from said recursive reflecting part to said light receiving element and serves to selectively allow said first linearly polarized light to pass therethrough.
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Abstract
A recursive-reflective photoelectric sensor has a sensor main body and a recursive reflecting part. The sensor main body includes a light projecting part that projects first circularly polarized light and a light receiving part. When a mixture of the first circularly polarized light and second circularly polarized light which is differently polarized from the first circularly polarized light is incident to the light receiving part, only the second circularly polarized light is selectively passed. The recursive reflecting part reflects the first circularly polarized light by converting into reflected light that includes the second circularly polarized light.
6 Citations
12 Claims
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1. A recursive-reflective photoelectric sensor comprising:
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a sensor main body including a light projecting part that projects first circularly polarized light and a light receiving part that selectively receives, when a mixture of the first circularly polarized light and second circularly polarized light which is differently polarized from said first circularly polarized light is incident thereto, said second circularly polarized light; and a recursive reflecting part that reflects said first circularly polarized light by converting into reflected light that includes said second circularly polarized light; wherein said sensor main body includes; a light projecting element; a light receiving element; a first phase-shift plate that converts first linearly polarized light into said first circularly polarized light and said second circularly polarized light into said first linearly polarized light; and a first polarization filter that is placed between said light receiving element and said first phase-shift plate on a optical path from said recursive reflecting part to said light receiving element and serves to selectively allow said first linearly polarized light to pass therethrough. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A sensor main body of a recursive-reflective photoelectric sensor, said sensor main body comprising:
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a light projecting element; a light receiving element; a phase-shift plate that converts linearly polarized light into first circularly polarized light and second circularly polarized light, which is differently polarized from said first circularly polarized light, into said linearly polarized light; and a polarization filter that is placed between said light receiving element and said phase-shift plate on an optical path from a recursive reflecting part to said light receiving element and serves to selectively allow said linearly polarized light to pass therethrough. - View Dependent Claims (8, 9, 10, 11)
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12. A recursive reflecting part of a recursive-reflective photoelectric sensor, said recursive reflective part comprising:
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a reflector that reflects light recursively; a phase-shift plate that converts first circularly polarized light into linearly polarized light and said linearly polarized light into second circularly polarized light; and a polarization filter that is placed between said phase-shift plate and said reflector on an optical path from a sensor main body to said reflector and selectively passes said linearly polarized light therethrough.
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Specification