Search

US-12627877-B2 - Infrared image system and image guide for infrared image transfer

US12627877B2US 12627877 B2US12627877 B2US 12627877B2US-12627877-B2

Abstract

The invention relates to an infrared image system having a lens for generating an image of a motif having at least two different temperatures T1 and T2, an image guide associated with the lens at a distal end for image transfer and a detector unit for image capture. The detector unit is associated with a proximal end of the image guide and the ratio of the shared thermal resolution (NETD) of the image guide and the detector unit to the thermal resolution (NETD) of the detector unit is less than 10, preferably less than 5, particularly preferably less than 2.

Inventors

  • Stefan Weiser
  • Andrea Ravagli
  • Timothy Eagleson
  • Bernd Schultheis

Assignees

  • SCHOTT AG
  • SCHOTT NORTH AMERICA, INC.

Dates

Publication Date
20260512
Application Date
20230215
Priority Date
20220404

Claims (17)

  1. 1 . An infrared image system, comprising: a lens for generating an image of a motif with at least two different temperatures T1 and T2, an image guide for image transmission, a distal end of the image guide being assigned to the lens, a detector unit for image capture, the detector unit being assigned to a proximal end of the image guide, the ratio of the joint thermal resolution (NETD) of the image guide and the detector unit to the thermal resolution (NRTD) of the detector unit being less than 10, wherein the detector unit has a thermal resolution (NETD) which is less than 300 mK.
  2. 2 . The infrared image system according to claim 1 , wherein the detector unit has a thermal resolution (NETD) which is less than 200 mK, and/or wherein the image guide and the detector unit have a joint thermal resolution (NETD) which is less than 400 mK.
  3. 3 . The infrared image system according to claim 1 , wherein the detector unit has a detectivity of at least 10 8 cm Hz 1/2 W −1 , for a wavelength in the infrared range, and/or wherein the detector unit has a resolution of at least 20 line pairs/mm and/or wherein the detector unit has an area of at least 0.1 square centimeters.
  4. 4 . The infrared image system according to claim 1 , further comprising an optical element arranged between the proximal end of the image guide and the detector unit and/or wherein the detector unit is embodied as a screen and the optical element is designed for image projection onto the screen and/or wherein the image guide of the infrared image system is embodied.
  5. 5 . The infrared image system according to claim 1 , wherein the ratio of the joint thermal resolution (NETD) of the image guide and the detector unit to the thermal resolution (NRTD) of the detector unit is less than 5.
  6. 6 . The infrared image system according to claim 1 , wherein the ratio of the joint thermal resolution (NETD) of the image guide and the detector unit to the thermal resolution (NRTD) of the detector unit is less than 2.
  7. 7 . The infrared image system according to claim 5 , wherein the image guide and the detector unit have a joint thermal resolution (NETD) which is less than 100 mK.
  8. 8 . The infrared image system according to claim 2 , wherein the image guide and the detector unit have a joint thermal resolution (NETD) which is less than 300 mK.
  9. 9 . The infrared image system according to claim 8 , wherein the image guide and the detector unit have a joint thermal resolution (NETD) which is less than 200 mK.
  10. 10 . The infrared image system according to claim 3 , wherein the detector unit has a detectivity of at least 10 9 cm Hz 1/2 W −1 .
  11. 11 . The infrared image system according to claim 10 , wherein the detector unit has a detectivity of at least least 10 10 cm Hz 1/2 W −1 .
  12. 12 . The infrared image system according to claim 8 , wherein the detector unit has a detectivity of at least least 10 11 cm Hz 1/2 W −1 .
  13. 13 . The infrared image system according to claim 3 , wherein the detector unit has a resolution of at least 50 line pairs/mm.
  14. 14 . The infrared image system according to claim 13 , wherein the detector unit has a resolution of at least 150 line pairs/mm.
  15. 15 . The infrared image system according to claim 3 , wherein the detector unit has an area of at least 0.5 square centimeters.
  16. 16 . The infrared image system according to claim 3 , wherein the detector unit has an area of at least 5 square centimeters.
  17. 17 . The infrared image system according to claim 3 , wherein the wavelength in the infrared range is from 0.8 μm to 14 μm.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a 371 national phase entry of PCT/EP2023/053739, filed Feb. 15, 2023, which claims the benefit of U.S. Provisional Application No. 63/268,199 filed Feb. 18, 2022, and of German Patent Application No. 10 2022 107 936.8 filed Apr. 4, 2022. FIELD OF THE INVENTION Infrared imaging can be used in a number of applications, for the purposes of providing information or auxiliary data which are not derivable by using the naked eye or conventional imaging equipment. BACKGROUND OF THE INVENTION In this context, it is sometimes desirable to separate the piece of imaging equipment, in particular the sensor, from the light-collecting lens in order to enable a space- and application-optimized usability, especially in small and dangerous surroundings. A suitable image guide can be used to transmit the IR light image captured by the lens to the sensor over a desired distance. Expanding the light spectrum may allow earlier prevention, performance optimization and/or risk reduction in relation to material defects, for example in industrial applications. Moreover, monitoring surroundings characterized by a high outage risk and non-usability of conventional IR imaging equipment on account of e.g. overall space-related, thermal, magnetic and/or other electro-optical blocking, for example, can be enabled by separating electro-optical imaging equipment from the observation object by way of IR light-guiding extensions. Consequently, flexibilizing the positioning is rendered possible by an extension. By way of a suitable placement for the localization of danger and risk sites (best-case prevention) and the identification of material effects, occurring there, as a result of a broader wavelength spectrum, the use of IR image guides brings about a dedicated local risk minimization and a better performance in relation to the avoidance of damage and the reduction in the service life of electro-optical imaging equipment. This is particularly applicable to small and dangerous surroundings, e.g. in industry and aviation. Furthermore, fields of application for infrared imaging can be, for example, preventative servicing of sheaths and insulations in narrow and/or difficult-to-access surroundings, monitoring of motors and engine rooms, possibly even during operation, monitoring and inspection of turbine chambers, for instance a blade inspection, e.g. in relation to weight, space and avionics balance, fire safety, firefighting, spark identification, for example in industrial infrastructure, in production, e.g. in relation to material supply lines or exhaust gas lines, within chambers, furnaces or switchboards, measurement applications and scientific applications, e.g. in the field of chemical and/or physical processes, for example under magnetic or vacuum conditions, in the field of circuit boards, wafers and the like. In this case, as a result of spatial separation from a detector unit, the use of IR image guides can enable a suitable placement, for example inconspicuous placement, of the infrared image system, for example also around the corner or around obstacles. In many applications, it is moreover also possible to obtain indirect insight, i.e. states or events can also be detected or observed within or outside of a housing or chamber, for example. In general, there sometimes is a desire for optical systems which are able to identify temperature differences between an object and the surroundings (thermal imaging technology). In this context, the aspect of an image transmission element (image guide) comes to bear if the direct exposure or direct observation, inter alia by way of an IR camera, is not possible or not preferable, or, expressed differently, if remote imaging is required, for example in difficult surroundings or at difficult-to-access sites, assemblies or the like, e.g. imaging around a corner, through small openings or between assemblies, etc. This is sometimes also the case in medical fields, for imaging into, out of or within a body. In this context, an image guide can enable remote imaging, with the distal end being kept away from the detector. IR cameras or IR detector image chips are usually not comparable to those from the visible range. The pixel size is frequently larger as a result of the adaptation to the wavelength range to be detected, and consequently the resolution tends to be rather low. Therefore, there has been increased interest in the development of highly sensitive, high-resolution sensors or detectors for some time now, in part also in view of relatively specific applications. By contrast, the development of image transmission elements in this context still has been less of a focus of development. In particular, image guides that are better matched to the respective system would be desirable. What also needs to be considered in this context is that in the IR range many bodies may act as IR transmitters themselves and might thus interfere with a ta