Infrared detector

• US 8,309,927 B2
• Filed: 04/20/2010
• Issued: 11/13/2012
• Est. Priority Date: 09/08/2009
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Kimura, Norio, Masai, Shigeo, Nakanosai, Yasuhiro
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): Maupin, Hugh H
• Application Number:
  US12/763,803
• Publication Number:
  US 20110057106A1
• Time in Patent Office: 938 Days
• Field of Search: 250/338.3
• US Class Current: 250/338.3
• CPC Class Codes: G01J 1/46 using a capacitor
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/0205 Mechanical elements; Supports for optical elements
• CPC Class Codes: G01J 5/023 Particular leg structure or construction or shape; Nanotubes
• CPC Class Codes: G01J 5/04 Casings
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G01J 5/0875 Windows; Arrangements for fastening thereof
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 2924/16151 Cap comprising an aperture, e.g. for pressure control, encapsulation
• CPC Class Codes: H01L 2924/16152 Cap comprising a cavity for hosting the device, e.g. U-shaped cap

Abstract

An infrared detector includes a pyroelectric element, a first amplifier, and a second amplifier. The pyroelectric element includes a first electrode formed on a first surface of a pyroelectric body, and a second electrode formed on the opposite surface. The first amplifier is connected to the first electrode, and amplifies signals induced to the first electrode. The second amplifier is connected to the second electrode, and amplifies signals induced to the second electrode.

Claims

1. An infrared detector, comprising:

at least one pyroelectric element including a pyroelectric body and a first electrode and a second electrode formed on opposing surfaces of the pyroelectric body;

a first amplifier connected to the first electrode, and amplifying signals induced to the first electrode; and

a second amplifier connected to the second electrode, and amplifying signals induced to the second electrode.

2. The infrared detector of claim 1, further comprising a case housing the pyroelectric element, the first amplifier, and the second amplifier.

3. The infrared detector of claim 2, wherein

the case includes

a substrate on which the pyroelectric element, the first amplifier, and the second amplifier are mounted, and

a cap covering the substrate, and

the cap includes an infrared transmissive window through which infrared light is transmitted to the pyroelectric element.

4. The infrared detector of claim 2, wherein

the case includes

a substrate on which the pyroelectric element, the first amplifier, and the second amplifier are mounted, and

a cap covering the substrate, and

the substrate includes an infrared transmissive window through which infrared light is transmitted to the pyroelectric element.

5. The infrared detector of claim 3, wherein

the substrate includes a first balanced output terminal and a second balanced output terminal formed on a surface opposite to a surface on which the pyroelectric element is mounted,

the first balanced output terminal is connected to an output of the first amplifier, and

the second balanced output terminal is connected to an output of the second amplifier.

6. The infrared detector of claim 5, wherein

the cap is made of metal, and

the cap is electrically connected to ground terminal formed on the surface of the substrate opposite to the surface on which the pyroelectric element is mounted.

7. The infrared detector of claim 1, wherein

the at least one pyroelectric element includes multiple ones of the at least one pyroelectric element, and

the multiple pyroelectric elements are connected together in parallel.

8. The infrared detector of claim 1, wherein the first amplifier and the second amplifier are capacitively coupled charge amplifiers.

9. The infrared detector of claim 1, wherein the first amplifier and the second amplifier are integrated together.

10. The infrared detector of claim 1, wherein an output signal of the first amplifier and an output signal of the second amplifier are substantially opposite in phase.

11. The infrared detector of claim 1, wherein the first electrode is not connected to ground.

12. The infrared detector of claim 1, wherein the second electrode is not connected to ground.

13. The infrared detector of claim 1, further comprising a third amplifier performing subtraction between an output signal of the first amplifier and an output signal of the second amplifier.

14. The infrared detector of claim 13, wherein the first amplifier, the second amplifier, and the third amplifier are integrated together.

15. The infrared detector of claim 1, further comprising an analog/digital converter for performing analog/digital conversion of an output signal from the first amplifier and an output signal from the second amplifier.

16. The infrared detector of claim 15, wherein the first amplifier, the second amplifier, and the analog/digital converter are integrated together.

17. The infrared detector of claim 15, wherein the analog/digital converter is a Δ

Σ

converter.

18. The infrared detector of claim 15, wherein the analog/digital converter outputs a digital signal in a pulse density modulation form.