Emissivity target having a resistive thin film heater

• US 5,756,991 A
• Filed: 08/14/1996
• Issued: 05/26/1998
• Est. Priority Date: 08/14/1996
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: James, Richard A., Risinger, Bradley R.
• Primary Examiner(s): Hannaher, Constantine
• Application Number:
  US08/696,760
• Time in Patent Office: 650 Days
• Field of Search: 250/252.1 A, 250/504 R
• US Class Current: 250/252.1
• CPC Class Codes: F41J 2/02 Active targets transmitting infrared radiation

Abstract

An electro-optical target and test apparatus having an improved resistive heating element. The resistive heating element comprises a resistive thin film coating layer, such as an indium tin oxide resistive coating layer, a resistive thin film semiconductor coating layer, or an electrically resistive polymer layer, that is disposed on a back side of a substrate. The substrate has a target pattern disposed on its front surface that to provide an emissivity target. The resistive coating layer provides a means for heating the substrate which produces a uniform source of thermal radiation because it has no holes therein. The resistive heating element is heated to radiate at a controlled target temperature set by a temperature controller coupled thereto. The materials comprising the coating layer and substrate may be transparent to visible and near infrared radiation. This allows radiation from visible and near infrared components of the system under test to pass through the substrate and resistive heating element to detector(s) located behind the heating element without requiring holes in the emissivity target. Also, use of a transparent substrate and heating element allows the use of visible and/or infrared light sources disposed behind the heating element, and thus the electro-optical target can simultaneously radiate both visible and infrared radiation at the system under test.

Claims

1. An electro-optical emissivity target comprising:

a substrate having a predetermined target pattern disposed on a front surface thereof; and

a heatable resistive coating layer disposed on a rear surface of the substrate wherein the coating layer comprises an indium tin oxide coating layer.

2. An electro-optical emissivity target comprising:

a substrate having a predetermined target pattern disposed on a front surface thereof; and

a heatable resistive coating layer disposed on a rear surface of the substrate wherein the coating layer comprises a resistive thin film semiconductor coating layer.

3. An electro-optical emissivity target comprising:

a substrate having a predetermined target pattern disposed on a front surface thereof; and

a heatable resistive coating layer disposed on a rear surface of the substrate wherein the coating layer comprises a transparent resistive thin film semiconductor coating layer.

4. An electro-optical emissivity target comprising:

a substrate having a predetermined target pattern disposed on a front surface thereof; and

a heatable resistive coating layer disposed on a rear surface of the substrate, further comprising a light source and a detector disposed in back of the coating layer that is used to radiate and detect radiation in predetermined wavelength bands, respectively.

5. An electro-optical emissivity target comprising:

a substrate having a predetermined target pattern disposed on a front surface thereof wherein the substrate comprises glass; and

a heatable resistive coating layer disposed on a rear surface of the substrate.

6. Test apparatus for use in testing a system under test, said apparatus comprising:

an emissivity target comprising;

a substrate having a predetermined target pattern disposed on a front surface thereof; and

a heatable resistive coating layer disposed on a rear surface of the substrate wherein the coating layer comprises an indium tin oxide coating layer;

a temperature controller coupled to the resistive coating layer for controlling its temperature; and

collimating optics for collimating energy emitted by and reflected from the emissivity target and for directing the collimated energy at the system under test.

7. Test apparatus for use in testing a system under test, said apparatus comprising:

an emissivity target comprising;

a substrate having a predetermined target pattern disposed on a front surface thereof; and

a heatable resistive coating layer disposed on a rear surface of the substrate wherein the coating layer comprises a resistive thin film semiconductor coating layer;

a temperature controller coupled to the resistive coating layer for contrlling its temperature; and

collimating optics for collimating energy emitted by and reflected from the emissivity target and for directing the collimated energy at the system under test.

8. Test apparatus for use in testing a system under test, said apparatus comprising:

an emissivity target comprising;

a substrate having a predetermined target pattern disposed on a front surface thereof; and

a heatable resistive coating layer disposed on a rear surface of the substrate wherein the resistive coating layer is transparent;

a temperature controller coupled to the resistive coating layer for controlling its temperature; and

collimating optics for collimating energy emitted by and reflected from the emissivity target and for directing the collimated energy at the system under test.

9. Test apparatus for use in testing a system under test, said apparatus comprising:

an emissivity target comprising;

a substrate having a predetermined target pattern disposed on a front surface thereof; and

a heatable resistive coating layer disposed on a rear surface of the substrate wherein the resistive coating layer is transparent;

a temperature controller coupled to the resistive coating layer for controlling its temperature; and

collimating optics for collimating energy emitted by and reflected from the emissivity target and for directing the collimated energy at the system under test further comprising;

a light source disposed adjacent a rear surface of the coating layer for irradiating the system under test with radiation at predetermined wavelengths; and

a detector disposed adjacent the rear surface of the coating layer for detecting radiation at predetermined wavelengths derived from the system under test.

10. Test apparatus for use in testing a system under test, said apparatus comprising:

an emissivity target comprising;

a substrate having a predetermined target pattern disposed on a front surface thereof; and

a heatable resistive coating layer disposed on a rear surface of the substrate wherein the substrate comprises glass;

a temperature controller coupled to the resistive coating layer for controlling its temperature; and

collimating optics for collimating energy emitted by and reflected from the emissivity target and for directing the collimated energy at the system under test.