Infrared sensing device and method

• US 5,844,240 A
• Filed: 07/12/1996
• Issued: 12/01/1998
• Est. Priority Date: 07/13/1995
• Status: Expired due to Term

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Lee, Don-Hee, Kim, Hak-Su
• Primary Examiner(s): Hannaher, Constantine
• Application Number:
  US08/679,075
• Time in Patent Office: 872 Days
• Field of Search: 250/DIG. 1, 250/342
• US Class Current: 250/342
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/026 Control of working procedures of a pyrometer, other than calibration; Bandwidth calculation; Gain control
• CPC Class Codes: G01J 5/06 Arrangements for eliminating effects of disturbing radiation; Arrangements for compensating changes in sensitivity for adjusting of solid angle of collected radiation G01J5/07; means for wavelength selection G01J5/0801
• CPC Class Codes: G01J 5/07 Arrangements for adjusting the solid angle of collected radiation, e.g. adjusting or orienting field of view, tracking position or encoding angular position optical collimating elements G01J5/0806
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G01J 5/0801 Means for wavelength selection or discrimination
• CPC Class Codes: G01J 5/0802 Optical filters
• CPC Class Codes: G01J 5/0806 Focusing or collimating elements, e.g. lenses or concave mirrors
• CPC Class Codes: G01J 5/0808 Convex mirrors
• CPC Class Codes: G01J 5/0846 having multiple detectors for performing different types of detection, e.g. using radiometry and reflectometry channels
• CPC Class Codes: G01J 5/10 using electric radiation detectors
• CPC Class Codes: G01P 13/00 Indicating or recording presence, absence, or direction, of movement electric switches H01H; counting moving objects G06M7/00
• CPC Class Codes: G01S 3/782 Systems for determining direction or deviation from predetermined direction
• CPC Class Codes: G01V 8/10 Detecting, e.g. by using light barriers by reflection from the object G01S17/00
• CPC Class Codes: G08B 13/19 using infrared-radiation detection systems G08B13/194 takes precedence
• CPC Class Codes: Y10S 250/01 Passive intrusion detectors

Abstract

An infrared sensing device includes a condensing lens for gathering an infrared ray from a human body, a guide unit for dividing a room to be monitored into a plurality of lateral and vertical zones and for guiding the infrared ray to a part of an infrared sensor unit corresponding to its direction, a housing for enclosing the condensing lens and guide unit to preclude dispersion of the incident infrared ray, an infrared sensor unit for sensing an infrared ray of a certain zone or infrared rays of a plurality of zones guided by the guide unit and housing, and a signal processing unit for amplifying an output signal of the infrared sensor unit, and for converting the applied signal into a digital signal and analyzing the digital signal.

Claims

1. A sensing device for sensing infrared ray from a subject in an area having a plurality of zones, the sensing device comprising:

a housing;

a lens in the housing, the lens focusing the infrared ray from the subject located at one of the plurality of zones in the area;

a sensor unit for receiving the infrared ray and outputting a sensed signal, the sensing unit including an infrared detector having detecting elements corresponding to the plurality of zones, the detecting elements including;

a first detecting element for detecting a first zone.

a second detecting element for detecting a second zone, a combination of the first and second detecting elements detecting a third zone, and

a third detecting element detecting a distance from the sensor device to the subject, wherein the first, second, and third detecting elements cover the area having the plurality of zones including the first, second, and third zones;

a guide unit adjacent to the lens, the guide unit directing the infrared ray to the sensor unit corresponding to an incident direction of the infrared ray; and

a signal processor coupled to the sensor unit and receiving the sensed signal, the signal processor determining where the subject is located from the sensed signal and producing a corresponding output signal.

2. The sensing device according to claim 1, wherein the lens includes a fresnel lens.

3. The sensing device according to claim 1, wherein the first zone includes a left zone, the second zone includes a right zone, and the third zone includes a central zone.

4. The sensing device according to claim 1, wherein the signal processor includes:

an amplifying unit coupled to the sensor unit and amplifying signals produced from the first and second detecting elements, respectively;

an analog to digital converter coupled to the amplifying unit and converting the amplified signals to digital signals.

5. The sensing device according to claim 4, wherein the signal processor further includes a comparator for comparing the digital signals from the analog to digital converter corresponding to the first and second detecting elements to produce an intermediate signal corresponding to the third zone.

6. The sensing device according to claim 1, wherein the third detecting element and at least one of the first and second detecting elements are combined to detect a fourth zone.

7. The sensing device according to claim 6, wherein the first zone includes a left zone, the second zone includes a right zone, the third zone includes a central zone.

8. The sensing device according to claim 6, wherein the fourth zone is divided into a first subzone and a second subzone, the first subzone being closer to the sensor unit than the second subzone.

9. The sensing device according to claim 6, wherein the signal processor includes:

an amplifying unit coupled to the sensor unit and amplifying signals produced from the first, second, and third detecting elements, respectively;

an analog to digital converter coupled to the amplifying unit and converting the amplified signals to digital signals.

10. The sensing device according to claim 9, wherein the signal processor further includes a comparator for comparing the digital signals from the analog to digital converter corresponding to the first and second detecting elements to produce an intermediate signal corresponding to the third zone.

11. The sensing device according to claim 1, wherein the sensor unit further includes:

an infrared filter for passing an infrared ray;

a support member for supporting the infrared detector; and

a package for protecting the infrared filter, the infrared detector, and the support member from external environments

wherein the infrared detector senses the infrared ray passed through the infrared filter and generates pyroelectricity.

12. The sensing device according to claim 11, wherein the sensor unit further includes an impedance transformer having the detecting elements on the transformer, the transformer being divided into multiple portions corresponding to the plurality of zones.

13. The sensing device according to claim 11, wherein

the first and second detector elements sense an infrared ray emitted from the plurality of zones including a left zone, a right zone, a central zone, and a first distance zone;

and

the third detector element senses an infrared ray emitted from a second distance zone.

14. The sensing device according to claim 1, wherein the guide unit divides the area into the plurality of zones.

15. The sensing device according to claim 14, wherein the guide unit includes:

a first guide section for dividing the area into a plurality of zones including left, right and central zones; and

a second guide section for dividing the area into a plurality of zones including short distance and long distance zones relative to the sensor unit.

16. The sensing device according to claim 15, wherein the first guide and the second guide sections intersect with each other.

17. The sensing device according to claim 1, wherein the guide unit has a fan shape.

18. The sensing device according to claim 1, wherein the first element has a first size, the second element has a second size, and the third element has a third size, the first and second sizes having substantially same size and the third size being substantially equal to a sum of the first and second sizes.

19. A method for sensing an infrared ray using a sensor from a subject in an area having a plurality of zones, the method comprising the steps of:

focusing the infrared ray from the subject located at one of the plurality of zones in the area;

directing the infrared ray to the sensor corresponding to an incident direction of the infrared ray;

detecting the infrared ray using at least first and second detecting elements for detecting first and second zones, respectively, and producing a sensed signal, the detecting step including the steps of;

combining the first and second elements to detect a third zone, and

using a third detecting element for detecting a distance from the sensor to the subject, wherein the first, second, and third detecting elements cover the area having the plurality of zones; and

processing the sensed signal and determining where the subject is located from the sensed signal and producing a corresponding output signal.

20. The method according to claim 19, wherein the step of detecting infrared ray includes the step of detecting whether the infrared ray is emitted from one of the plurality of zones including left, right and central zones.

21. The method according to claim 20, wherein the step of detecting infrared ray includes the step of detecting whether the infrared ray is emitted from one of the plurality of zones including a first distance zone and a second distance zone.

22. A method for sensing a plurality of infrared rays using a sensor from a plurality of subjects located in an area having a plurality of zones, the method comprising the steps of:

focusing the infrared rays from the subjects located in at least one of the plurality of zones;

directing the infrared rays to the sensor corresponding to incident directions of the infrared rays;

detecting the infrared rays using at least first and second detecting elements for detecting first and second zones, respectively, and producing sensed signals, the detecting step including the steps of;

combining the first and second detecting elements to detect a third zone, and

using a third detecting element for detecting distances from the sensor to the subjects, wherein the first, second, and third detecting elements cover the area having the plurality of zones; and

processing the sensed signals and determining a number of subjects in a zone and where the subjects are located from the sensed signals and producing corresponding output signals.

23. The method according to claim 22, wherein the step of detecting infrared rays includes that step of detecting whether the infrared rays are emitted from left, right and central zones.

24. The method according to claim 22, wherein the step of detecting infrared rays includes that step of detecting whether the infrared rays are emitted from a first distance zone and a second distance zone.

25. A method for sensing electromagnetic radiation from a subject in an area having a plurality of zones using a sensor having a guide, the method comprising the steps of:

receiving the electromagnetic radiation from a subject;

guiding the received electromagnetic radiation to the sensor through the guide corresponding to an incident direction of the radiation;

sensing the electromagnetic radiation using at least first and second detecting elements for detecting first and second zones, respectively, and outputting a corresponding sensed signal, the sensing step including the steps of;

combining the first and second elements to detect a third zone, and

using a third detecting element for detecting a distance from the sensor to the subject, wherein the first, second, and third detecting elements cover the area having the plurality of zones; and

processing the corresponding signal and determining where the subject is located from the sensed signal and producing an output signal.

26. A method for sensing an infrared ray emitted from a subject using an infrared sensing device, the method comprising the steps of:

detecting an incident infrared ray from one of left, right, and central zones of an area divided into a plurality of zones using at least first and second detecting elements for detecting the left and right zones, respectively, the detecting step including the steps of;

combining the first and second elements to detect the central zone, and

using a third detecting element for detecting a distance from the sensor to the subject, wherein the first, second, and third detecting elements cover the area divided into the plurality of zones;

determining an amount of activity from the subject; and

determining a location of the subject relative to the infrared sensing device.

27. The method according to claim 26, wherein the step of detecting the incident infrared ray detects a relative distance from which the infrared ray was emitted.

28. The method according to claim 27, wherein the step of detecting the relative distance includes the step of determining an intensity of the infrared ray.