US4318089A — Infrared detector system

Claim 1

Independent Claim 111 words

An infrared detector system comprising; at least a pair of spaced apart infrared sensing elements capable of generating respective first and second electrical signals; a plurality of reflective surfaces subtending respective different object fields of view, about a respective optical axis, each reflective surface having a focal point positioned on its optical axis between the respective infrared sensing elements and reflecting optimum energy resolution of an image configuration compatible to the sensing element configuration whereby movement of an infrared emitting object will produce a sequence of electrical signals from the infrared sensing elements; and means for processing the electrical signals to produce an alarm signal in response to predetermined enabling conditions.

Claim 2

Dependent Claim 111 words

An infrared detector system comprising; at least a pair of spaced apart infrared sensing elements capable of generating respective first and second electrical signals; a plurality of reflective surfaces subtending respective different object fields of view, about a respective optical axis, each reflective surface having a focal point positioned on its optical axis between the respective infrared sensing elements and reflecting optimum energy resolution of an image configuration compatible to the sensing element configuration whereby movement of an infrared emitting object will produce a sequence of electrical signals from the infrared sensing elements; and means for processing the electrical signals to produce an alarm signal in response to predetermined enabling conditions.

Claim 3

Dependent Claim 11 words

The invention of claim 1 wherein the reflective surfaces are aspherical.

Claim 4

Dependent Claim 48 words

The invention of claim 1 wherein each reflective surface is inclined relative to its adjacent reflective surface so that different regions of the object fields of view can be imaged onto the infrared sensing elements, each reflective surface having a common focal point between the infrared sensing elements.

Claim 5

Dependent Claim 22 words

The invention of claim 1 wherein each reflective surface is substantially identical and can be defined by the following equation: ##EQU2## wherein;

Claim 6

Dependent Claim 4 words

-0. 375≦C≦-0.365 -0.005≦A≦+0.005 -1.10≦K≦-0.90

Claim 7

Dependent Claim 4 words

-0. 375≦C≦-0.365 -0.005≦A≦+0.005 -1.10≦K≦-0.90

Claim 8

Dependent Claim 15 words

The invention of claim 1 wherein the reflective surfaces are on an aspheric fresnel element.

Claim 9

Dependent Claim 17 words

The invention of claim 1 wherein the infrared sensing elements are low impedance thin film thermopile elements.

Claim 10

Dependent Claim 30 words

The invention of claim 6 wherein the means for processing the electrical signals include a high gain direct current operational amplifier directly connected to the output of the thermopile elements.

Claim 11

Dependent Claim 42 words

The invention of claim 1 wherein the means for processing the electrical signals include a filter circuit having a high pass amplifier and a low pass amplifier to pass an amplified signal in the frequency range of 0.2 Hz to 15 Hz.

Claim 12

Dependent Claim 63 words

The invention of claim 1 wherein the means for processing the electrical signals include a combined peak detector and time dependent integrator summing amplifier circuit means to provide an alarm signal, the summing amplifier circuit means providing an enabling predetermined threshhold detector gate that requires one of a predetermined large signal level and a multiple of smaller electrical signals within a preselected interval.

Claim 13

Dependent Claim 48 words

The invention of claim 1 wherein the sensing elements are thin film thermopiles having active and inactive surfaces with an infrared energy absorbing coating layer extending over both surfaces to provide an increased signal to noise ratio at a slower response time than a conventional thin film thermopile.

Claim 14

Dependent Claim 29 words

The invention of claim 10 wherein the inactive surface area is coated with approximately twice the area coating of the infrared energy absorbing layer as the active surface area.

Claim 15

Dependent Claim 60 words

The invention of claim 1 wherein the infrared sensing elements have a rectangular configuration and are spaced horizontally apart from each other, and the respective reflective surfaces can optically an image of a human being that is non-coincidental with both sensors, the reflected image being elongated in the vertical plane to match the rectangular elongated configuration of the image sensor.

Claim 16

Dependent Claim 197 words

An infrared detector system comprising: detector means including at least a pair of infrared sensing elements capable of generating respective first and second electrical signals of opposite polarity; reflecting means including a plurality of aspheric reflector segments that partition the object field of view into discrete regions, each reflector segment subtending a different region and focusing incident infrared energy onto the detector means with minimal image aberration; circuit means for processing electrical signals from the detector means including a high gain low noise D.C. amplifier coupled to the output of the infrared sensing elements, a high pass amplifier and low pass amplifier coupled respectively in series to the output of the D.C. amplifier to pass an amplified signal in the frequency range of approximately 0.2 Hz to 15 Hz and a combined peak detector and time dependent integrator summing amplifier circuit receiving the signal from the low pass amplifier to provide an enabling predetermined threshhold detection gate that requires one of, a predetermined large signal level and a multiple of small electrical signals within a preselected interval, to produce an alarm enabling signal, and means responsive to the alarm signal to indicate the presence of an intruder.

Claim 17

Dependent Claim 197 words

An infrared detector system comprising: detector means including at least a pair of infrared sensing elements capable of generating respective first and second electrical signals of opposite polarity; reflecting means including a plurality of aspheric reflector segments that partition the object field of view into discrete regions, each reflector segment subtending a different region and focusing incident infrared energy onto the detector means with minimal image aberration; circuit means for processing electrical signals from the detector means including a high gain low noise D.C. amplifier coupled to the output of the infrared sensing elements, a high pass amplifier and low pass amplifier coupled respectively in series to the output of the D.C. amplifier to pass an amplified signal in the frequency range of approximately 0.2 Hz to 15 Hz and a combined peak detector and time dependent integrator summing amplifier circuit receiving the signal from the low pass amplifier to provide an enabling predetermined threshhold detection gate that requires one of, a predetermined large signal level and a multiple of small electrical signals within a preselected interval, to produce an alarm enabling signal, and means responsive to the alarm signal to indicate the presence of an intruder.

Claim 18

Dependent Claim 25 words

The invention of claim 13 wherein the aspheric reflector segments have a substantially identical configuration and can be defined by the following equation: ##EQU3## wherein;

Claim 19

Dependent Claim 4 words

-0. 375≦C≦-0.365 -0.005≦A≦+0.005 -1.10≦K<-0.90

Claim 20

Dependent Claim 4 words

-0. 375≦C≦-0.365 -0.005≦A≦+0.005 -1.10≦K<-0.90

Claim 21

Dependent Claim 15 words

The invention of claim 13 wherein the reflective segments are on an aspheric fresnel element.

Claim 22

Dependent Claim 48 words

The invention of claim 13 wherein each reflective segment is inclined relative to its adjacent reflective segment so that different regions of the object fields of view can be imaged onto the infrared sensing elements, each reflective segment having a common focal point between the infrared sensing elements.

Claim 23

Dependent Claim 48 words

The invention of claim 13 wherein the sensing elements are thin film thermopiles having active and inactive surfaces with an infrared energy absorbing coating layer extending over both surfaces to provide an increased signal to noise ratio at a slower response time than a conventional thin film thermopile.

Claim 24

Dependent Claim 29 words

The invention of claim 17 wherein the inactive surface area is coated with approximately twice the area coating of the infrared energy absorbing layer as the active surface area.

Claim 25

Dependent Claim 17 words

The invention of claim 16 wherein each reflective segment subtends an individual field of view of 3.5°.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1985-03-01	1985-08-31	1986-03-02	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1989-03-01	1989-08-31	1990-03-02	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1993-03-01	1993-08-31	1994-03-02	$7700.00	Window Closed / Lapsed

Infrared detector system

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