Infrared ray detector
First Claim
1. An infrared ray detector of dual structure having two electrically connected pyroelectric infrared ray detecting elements, said infrared ray detector comprising:
- a pair of pyroelectric infrared ray detecting elements having substantially identically directed light receiving surfaces, said pair of detecting elements having opposite polarities and being electrically connected with each other to generate an output signal representing the difference therebetween; and
a mirror means being spaced a predetermined distance in front of said light receiving surfaces, said mirror means having a predetermined width, said predetermined distance and predetermined width restricting an incident infrared light ray on one of said pair of detecting elements while another of said pair of detecting elements receives said incident infrared light ray directly on the light receiving surface and also receives a reflected infrared light ray from said mirror means.
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Abstract
A pyroelectric infrared ray detector of the so-called dual structure for detecting an intruder or the like through differential output of two pyroelectric infrared ray detecting elements connected in parallel or series to each other. The infrared ray detector comprises a pair of pyroelectric infrared ray detecting elements having substantially identically directed light receiving surfaces and electrically connected to each other and a shield member arranged in front of the said light receiving surfaces to partially shield the infrared ray detecting elements against incidence of infrared light. The shield member is arranged in a plane extending between the infrared ray detecting elements to separate the same on both sides thereof.
52 Citations
19 Claims
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1. An infrared ray detector of dual structure having two electrically connected pyroelectric infrared ray detecting elements, said infrared ray detector comprising:
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a pair of pyroelectric infrared ray detecting elements having substantially identically directed light receiving surfaces, said pair of detecting elements having opposite polarities and being electrically connected with each other to generate an output signal representing the difference therebetween; and a mirror means being spaced a predetermined distance in front of said light receiving surfaces, said mirror means having a predetermined width, said predetermined distance and predetermined width restricting an incident infrared light ray on one of said pair of detecting elements while another of said pair of detecting elements receives said incident infrared light ray directly on the light receiving surface and also receives a reflected infrared light ray from said mirror means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An infrared ray detector of dual structure having two electrically connected pyroelectric infrared ray detecting elements, said infrared ray detector comprising:
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a sensor portion having a pair of pyroelectric infrared ray detecting elements having substantially identically directed light receiving surfaces, said pair of detecting elements having opposite polarities and being electrically connected with each other to generate an output signal representing the difference therebetween, a ceramic substrate having front and rear surfaces, said pair of detecting elements being fixed to said front surface of said ceramic substrate, a metal case having an entrance window, and a impedance circuit arranged on said rear surface of said ceramic substrate; a frame member having a central space, said sensor portion being mounted in said central space with said entrance window directed to an exterior of said frame member, said frame member having a processing circuit for processing signals determined by said sensor portion; mirror means being spaced a predetermined distance in front of said light receiving surfaces of said pair of detecting elements, said mirror means having a predetermined width, said predetermined distance and predetermined width of said mirror means restricting an incident infrared light ray on one of said pair of detecting elements while another of said pair of detecting elements receives said incident infrared light ray directly on the light receiving surface and also receives a reflected infrared light ray from said mirror means, said mirror means including a plurality of mirrors being provided at predetermined intervals along said central space of said frame member; and cover member for covering said mirror means. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification