SENSOR SYSTEM FOR DETECTING A MOVEMENT OF AN INFRARED LIGHT SOURCE

• US 20150169086A1
• Filed: 02/20/2015
• Published: 06/18/2015
• Est. Priority Date: 08/22/2012
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Pyreos Ltd. (Broadcom, Inc.)
• Inventors: Giebeler, Carsten, Wojtczuk, Piotr, Binnie, David
• Granted Patent: US 9,367,143 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01J 1/0266 Field-of-view determination; Aiming or pointing of a photometer; Adjusting alignment; Encoding angular position; Size of the measurement area; Position tracking; Photodetection involving different fields of view for a single detector
• CPC Class Codes: G01J 1/06 Restricting the angle of incident light
• CPC Class Codes: G01J 5/0025 Living bodies ear thermometers G01J5/0011; detecting, measuring or recording for diagnostic purposes A61B5/00
• 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 5/0831 Masks; Aperture plates; Spatial light modulators
• CPC Class Codes: G01J 5/0875 Windows; Arrangements for fastening thereof
• CPC Class Codes: G01J 5/34 using capacitors, e.g. pyroelectric capacitors
• CPC Class Codes: G01S 17/66 Tracking systems using electromagnetic waves other than radio waves
• CPC Class Codes: G06F 3/0325 using a plurality of light emitters or reflectors or a plurality of detectors forming a reference frame from which to derive the orientation of the object, e.g. by triangulation or on the basis of reference deformation in the picked up image

Abstract

A sensor system for detecting motion in a predefined direction of motion (30) of an infrared light source (29) has at least one pair of infrared light sensors (4, 5; 36, 37), which are arranged side by side with respect to the direction of motion (30) and, thus, define a sensor coverage zone (17) determined by the distance between distal ends (16) (with respect to the direction of motion) of the infrared light sensors. During exposure to the infrared light source, the sensors provide electrical signals, the charge signs of which are opposite each other, for detecting the motion of the infrared light source (29). The sensor system (1) has a window (7) positioned between the infrared light source (29) and the sensors such that the infrared light of the infrared light source (29) radiates onto the sensors. The sensors are arranged behind the window and are adjusted relative to the width (41) of the window to extend in the direction of motion such that, beyond a predetermined limit distance (20) away from the window, each of the sensors has a full illumination zone (22, 23), which defines the locations from which the infrared light source (29) fully illuminates only one of the sensors (4, 36 or 5, 37). The full illumination zones (22, 23) do not spatially overlap beyond the limit distance (20); and the window width (41) is smaller than the sensor coverage zone (17) in the direction of motion (30).

Claims

1. Sensor system for detecting a motion in a predefined direction of motion of an infrared light source, said sensor system comprising:

at least one pair of infrared light sensors, said pair consisting of two infrared light sensors arranged side by side with respect to the direction of motion and thereby defining a sensor coverage zone determined by the distance between mutually distal ends of the infrared light sensors with respect to the direction of motion,

wherein the infrared light sensors are configured to provide electrical signals having mutually opposite charge signs in response to exposure to infrared light from the infrared light source, for detecting the motion of the infrared light source, and

a window between the infrared light source and the infrared light sensors,

wherein the window is configured to pass the infrared light of the infrared light source onto the infrared light sensors, and wherein the infrared light sensors are arranged to extend in the direction of motion and are configured to a width of the window such that beyond a predetermined limit distance away from the window, each of the infrared light sensors has a respective full illumination zone, which defines the respective locations from which the infrared light source fully illuminates only one of the infrared light sensors, and

wherein the full illumination zones do not spatially overlap beyond the limit distance, and the width of the window is smaller than the sensor coverage zone in the direction of motion.

2. Sensor system, as claimed in claim 1, wherein, in the direction of motion, the sensor coverage zone projects beyond the window on both sides of the window and to an equal extent.

3. Sensor system, as claimed in claim 1, wherein the infrared light sensors are configured such that, upon exposure to the infrared light source with equal intensity, the electrical signals are equally strong.

4. Sensor system, as claimed in claim 1, wherein the infrared light sensors are pyroelectric sensors.

5. Sensor system, as claimed in claim 1, wherein each of the infrared light sensors has a signal line, with which the electrical signals of the infrared light sensors are tapped off, and wherein the signal lines are connected to a signal bus line of the sensor system.

6. Sensor system, as claimed in claim 1, wherein the width of the window in the direction of motion is between 0.7 and 1 times the sensor coverage zone.

7. Sensor system, as claimed in claim 1, wherein, with respect to the extent of the window, each infrared light sensor defines a sensor outer edge and a sensor inner edge, wherein a first window edge, which is immediately adjacent to the sensor inner edge, and a second window edge, which is immediately adjacent to the sensor outer edge, are defined by the window, wherein a straight line from the sensor inner edge to the first window edge and the sensor normal enclose a first angle, and wherein the sensor normal and a straight line from the sensor outer edge to the second window edge enclose a third angle, wherein the difference between the absolute value of the first angle and the absolute value of the third angle is greater than twice the absolute value of the third angle.

8. Sensor system, as claimed in claim 1, wherein with respect to the extent of the window, each infrared light sensor defines a sensor outer edge and a sensor inner edge, wherein a first window edge, which is immediately adjacent to the sensor inner edge, and a second window edge, which is immediately adjacent to the sensor outer edge, are defined by the window, wherein a straight line from the sensor inner edge to the second window edge and the sensor normal enclose a second angle, and wherein the sensor normal and a straight line from the sensor outer edge to the second window edge enclose a third angle, wherein the absolute value of the third angle is between zero and the absolute value of the second angle.

9. Sensor system, as claimed in claim 1, wherein the sensor system comprises a second pair of infrared light sensors, the second pair consisting of two of the infrared light sensors, wherein the window is rectangular, and downstream of which the infrared light sensors are arranged as an array symmetrical to the window, wherein the infrared light sensors of the one pair of infrared light sensors are arranged on one diagonal line of the window, and the infrared light sensors of the second pair of infrared light sensors are arranged on the other diagonal line of the window, so that either the one diagonal line or the other diagonal line defines the direction of motion.

10. Sensor system, as claimed in claim 1, wherein the infrared light sensors and the window are configured such that, when the infrared light source is a human hand, the infrared light sensors provide, upon exposure to the hand, electrical signals for detecting the motion of the hand.

11. Sensor system, as claimed in claim 4, wherein the infrared light sensors comprise lead zirconate titanate and are inversely polarized.

12. Sensor system, as claimed in claim 6, wherein the window width in the direction of motion is between 0.8 and 0.9 times the coverage zone.

13. Sensor system, as claimed in claim 7, wherein the difference between the absolute value of the first angle and the absolute value of the third angle is between two times and four times the absolute value of the third angle.

14. Sensor system, as claimed in claim 8, wherein the absolute value of the third angle is between zero and 0.5 of the absolute value of the second angle.