Pyro-electric type infrared detector

• US 5,281,818 A
• Filed: 06/10/1991
• Issued: 01/25/1994
• Est. Priority Date: 06/11/1990
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yoshikawa, Motonobu, Yamamoto, Yoshiharu, Tomita, Yoshihiro, Takayama, Ryoichi
• Primary Examiner(s): Fields, Carolyn E.
• Assistant Examiner(s): Dunn, Drew A.
• Application Number:
  US07/712,681
• Time in Patent Office: 960 Days
• Field of Search: 250/347, 250/349, 250/338.3, 250/343, 250/352, 250/353, 340/600
• US Class Current: 250/347
• CPC Class Codes: G01J 2005/345 Arrays
• CPC Class Codes: G01J 5/34 using capacitors, e.g. pyroelectric capacitors

Abstract

An apparatus for detecting position or temperature distribution of an object has a lens which is rotated around a pyroelectric type infrared sensor to collect incident infrared ray on the sensor while scanning the incident infrared ray in a rotational direction. The optical scanning is operated also in the longitudinal direction by providing with a plurality of lenses having different view in the longitudinal direction, the lenses being rotated sequentialy around the sensor. Further, detection of temperature of an object is conducted without using optical chopper by alternately observing the object and a standard temperature material which is arranged in a part of view, or by providing a stationary slit unit on a curved surface formed around a center axis which is the same as the rotation axis of the lens and a movable slit unit having the same pitch and arranged adjacent to the stationary slit unit and rotating together with the lens to intermitting the incident infrared ray.

Claims

1. An infrared detecting apparatus comprising:

an array sensor having an array of pyro-electric type infrared detectors arranged in one direction;

a lens for collecting incident infrared rays on said array sensor;

a driving means for rotating said lens around said array sensor about a rotation axis parallel to the direction of arrangement of said infrared detectors to scan said incident infrared rays in a direction of rotation about said rotation axis;

a standard temperature material arranged adjacent to said lens in a part of view scanned by said lens, said standard temperature material being divided into a plurality of portions which are periodically arranged in the scanning direction; and

a signal processor coupled to said sensor array for measuring a temperature of an object by comparing an output from said sensor array when receiving infrared rays from said object with an output from said sensor array when receiving infrared rays from said standard temperature material,

wherein said array sensor and said lens are arranged to satisfy the following condition;

##EQU3## where, a is an effective diameter of said lens in the scanning direction, f is a focal length of said lens, w is an effective width of said array sensor in the scanning direction, and θ

is an angle formed between an utmost end of a measuring area and a center of the measuring area.