Passive filter for laser protection

Patent metadata

Field	Value
Publication number	US-10815720-B2
Application number	US-201716087116-A
Country	US
Kind code	B2
Filing date	Mar 17, 2017
Priority date	Mar 24, 2016
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

There is disclosed a filter for a vehicle window comprising a layer of filter material, the layer of filter material being for substantially preventing the transmission of radiation at a first predetermined visible wavelength band, the first predetermined visible wavelength band covering the wavelength of a predetermined laser threat, whilst substantially allowing visible wavelengths outside of the band to be transmitted, such that the filter can offer a visible light transmission of at least 70%, and a radiation detector, such that radiation at the first predetermined wavelength band can be detected.

First claim

The invention claimed is:

1. A passive filter for a vehicle window comprising:
a layer of filter material;
the layer of filter material being for substantially preventing the transmission of radiation at a first predetermined visible wavelength band;
the first predetermined visible wavelength band covering the wavelength of a predetermined laser threat, whilst substantially allowing visible wavelengths outside of the band to be transmitted;
such that the filter can offer a visible light transmission of at least 70%; and
a radiation detector arranged and configured in respect of said layer of filter material to detect radiation in the first predetermined wavelength band incident thereon and substantially blocked thereby; wherein the radiation detector extends solely about the periphery of the filter; and
wherein the radiation detector comprises:
a plurality of detector layers, each detector layer comprising detectors; whereby a location of the threat is established based at least in-part on relative locations of detectors within different detector layers.

2. The filter according to claim 1 wherein the detector layers are mounted on the layer of filter material.

3. The filter according to claim 1 wherein the radiation detector comprises an array of photodetector elements.

4. The filter according to claim 1 further comprising a processor module connected to the radiation detector, and a user alert module connected so the processor module such that an alert may be issued in the event of a detected laser threat.

5. The filter according to claim 1 wherein the filter comprises an interference filter configured to inhibit transmission at the or each predetermined wavelength band and formed by holographic exposure of a photosensitive film or films by one or more lasers.

6. The filter according to claim 1 wherein the filter is additionally for preventing transmission of radiation in a second predetermined wavelength band, the second predetermined wavelength band covering the wavelength of a second predetermined laser threat.

7. The filter according to claim 1 wherein the filter is for additionally preventing radiation in a third predetermined visible radiation band, the third predetermined wavelength band covering the wavelength of a third predetermined laser threat.

8. The filter according to claim 1 wherein the filter is for preventing radiation from no more than three predetermined radiation bands.

9. The filter according to claim 1 wherein the filter is comprised by a single layer of material adapted or configured for preventing the transmission of the predetermined visible wavelength band or bands.

10. The filter according to claim 1 wherein the bandwidth of at least one of a predetermined wavelength band is 10 nm.

11. The filter according to claim 1 wherein the filter has an optical density of at least 2 at the first predetermined wavelength band.

12. The filter according to claim 1 wherein the filter has an optical density of at least 2 at each of a predetermined wavelength band.

13. The filter according to claim 1 wherein the filter is provided as a conformal film for coupling to a window.

14. A multi-layered window comprising a passive filter for a vehicle window comprising:
a layer of filter material;
the layer of filter material being for substantially preventing the transmission of radiation at a first predetermined visible wavelength band;
the first predetermined visible wavelength band covering the wavelength of a predetermined laser threat, whilst substantially allowing visible wavelengths outside of the band to be transmitted;
such that the filter can offer a visible light transmission of at least 70%;
a radiation detector arranged and configured in respect of said layer of filter material to detect radiation in the first predetermined wavelength band incident thereon and substantially blocked thereby;
wherein the radiation detector comprises:
a plurality of detector layers, each detector layer comprising detectors; whereby a location of the threat is established based at least in-part on relative locations of detectors within different detector layers; and

wherein the filter is interposed between layers of the window.

15. The multi-layered window according to claim 14 wherein the detector layers are mounted on the layer of filter material.

16. The multi-layered window according to claim 14 wherein the detector layers are at a boundary of and generally co-planar with the layer of filter material.

17. The multi-layered window according to claim 14 wherein the detector layers comprise a patch arranged in a plane of the filter.

18. The multi-layered window according to claim 14 wherein the detector layers and filter material comprise a stacked multi-layer structure.

19. A window for a vehicle, the window comprising a passive filter for a vehicle window comprising:
a layer of filter material;
the layer of filter material being for substantially preventing the transmission of radiation at a first predetermined visible wavelength band;
the first predetermined visible wavelength band covering the wavelength of a predetermined laser threat, whilst substantially allowing visible wavelengths outside of the band to be transmitted;
such that the filter can offer a visible light transmission of at least 70%;
a radiation detector arranged and configured in respect of said layer of filter material to detect radiation in the first predetermined wavelength band incident thereon and substantially blocked thereby;
wherein the radiation detector extends solely about the periphery of the filter; and
wherein the radiation detector comprises:
a plurality of detector layers, each detector layer comprising detectors; whereby a location of the threat is established based at least in-part on relative locations of detectors within different detector layers.

Assignees

• Bae Systems Plc

Inventors

• Black Daniel Benjamin
• Akhmad Mohammed-Asif
• Laycock Leslie Charles

Classifications

• G02B1/005 Primary

  made of photonic crystals or photonic band gap materials (photonic band-gap structures or photonic lattices in integrated optics G02B6/1225; photonic band-gap structures or photonic lattices in optical fibres G02B6/02295) · CPC title

• G02B5/28 Primary

  Interference filters · CPC title

• G01S7/495

  Counter-measures or counter-counter-measures {using electronic or electro-optical means} · CPC title

• G01J1/42

  using electric radiation detectors (optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10) · CPC title

• B60Y2200/143

  Busses · CPC title