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Defense & Security

Patents: Visionary night vision devices

The latest featured patent review by analysts from Nerac examines devices that help to see in the dark.
3 May 2007, SPIE Newsroom. DOI: 10.1117/2.2200705.0002


In the first few months of 2007, at least four patents have issued and five applications have been published related to the field of night vision or image intensification technology. The granted patents include U.S. 7,170,057 to Night Vision Corporation, U.S. 7,166,871 to Luminus Devices, Inc., U.S. 7,158,296 to Insight Technology, Inc., and EP 1018142 to Litton Systems, Inc. (European version of U.S. 5,907,150 granted 5/25/1999); the pending applications include two by ITT Manufacturing, two by Vectronix AG, and one by Korry Electronics (US2007025106).


The '057 patent to Night Vision corporation is noteworthy because it solves two problems: the traditionally limited (40 degree circular) FOV associated with night vision devices, and the need to provide for rapid switching between intensified and normal images. The claimed apparatus uses four modular optical components to produce a panoramic field of vision (100 degree horizontal x 40 degree vertical), and incorporates in each component a liquid crystal dichroic narrow-band-pass filter that acts as a switchable beam splitter.


Three documents focus on the fusion of multi-spectral images for viewing through the same eyepiece(s): US2007013997, Day-night vision device (Vectronix AG, priority 7/14/2005); U.S. 5,907,150, Multi-function day/night observation, ranging, and sighting device and method of its operation (priority 7/28/1997); U.S. 7,158,296, Vision system with eye dominance forced to fusion channel (priority 7/2/2004). Each reference provides multiple optical channels segregated by wavelength spectra.


In one of the preferred embodiments of US2007013997, the optical components of the day vision channel are transparent or reflective for the wavelengths of the conterminous heat radiation channel. A separate objective is provided for image intensification. During the daytime, only the full-light image from the day vision channel is used. In reduced lighting, the day vision channel may continue to be viewed; the image intensified channel and the heat radiation channel also come into use. The intensified image is transmitted directly through the eyepiece with the day vision image, while the heat radiation image is projected as visible light using an LED/LCD display.


In EP 1018142 (Litton), the key concern is to display simultaneously a visible-light image, an intensified image, and numeric range data obtained from a laser pulse coaxial with the imaging optics. This is accomplished using a single objective lens backed by collimating and focal lens cells that separate visible and near-IR images to distinct focal planes. Rearward of the focal lens cell, an angulated dichroic prism and mirror are provided to split the beam to parallel visible and near-IR optical channels; while the near-IR channel passes through a photocathode / microchannel plate image intensifier, the visible channel is combined with the image of an LED range display. Prior to the eyepiece, a second prism-and-mirror assembly combine the visible images from visible and near-IR optical channels to provide a single fused image at the eyepiece.

As discussed in the Litton patent, with reference to U.S. 5,084,780 (ITT, priority 1/18/1991), lateral "jiggle" or axis-preferent motion parallax has been a disadvantage of prior single objective scopes using angulated dichroic mirrors. Despite its discussion of "jiggle" as a disadvantage of the prior art, EP 1018142 does not explain how its single objective lens optical arrangement mitigates this problem.

U.S. 7,158,296 to Insight takes a different approach to the parallax problem, incorporating a parallax compensation circuit to properly align the visible images from its two image intensifiers and single thermal imager. Like Litton's single objective scope, the Insight trinocular uses a partially reflective beam splitter to combine or fuse the thermal and intensified images at the dominant eyepiece. However, this appears to be the only optical element in the device, which is otherwise purely electro-optical.

1. Low cost planar image intensifier tube structure
EP1760758-A2, US20070023617-A1
INVENTOR-Thomas, Nils Ian
PATENT ASSIGNEE-ITT MANUFACTURING ENTERPRISES, INC.
An image intensifier tube is provided that has a microchannel plate (MCP), a photocathode and phosphor screen deposited on a fiber optic substrate. A first spacer is positioned between the microchannel plate and the fiber optic substrate. A second spacer is positioned between the fiber optic substrate and the photocathode. The first and second spacers cooperate to provide a spatial relationship among the MCP, phosphor screen and photocathode for effective operation of the image intensifier tube.
1. An image intensifier tube having a microchannel plate (MCP), a photocathode and a phosphor screen deposited on a fiber optic substrate, said image intensifier tube comprising: a first spacer positioned between said microchannel plate and said fiber optic substrate; and a second spacer positioned between said fiber optic substrate and said photocathode, wherein said first and second spacers cooperate to provide a spatial relationship among the MCP, phosphor screen and photocathode for effective operation of the image intensifier tube.

2. Night vision compatible area light fixture
US20070025106-A1
INVENTOR-Robinson, Timothy R.
APPLICANT-Korry Electronics Co.
A night vision equipment compatible area light fixture may include a housing, one or more LEDs such as gallium nitride or indium gallium nitride LEDs, and a filter assembly positioned to filter electromagnetic radiation with a wavelength of 950 nm. The filter may, for example, substantially block electromagnetic radiation with wavelengths between approximately 930 nm and approximately 1000 nm. The filter may additionally, for example, substantially blocking electromagnetic radiation with wavelengths between approximately 900 nm and approximately 1000 nm. The filter may further, for example, substantially block electromagnetic radiation with wavelengths between approximately 700 nm and approximately 1000 nm.

3. Image enhancement system and method for night goggles
US7170057
INVENTOR-Filipovich, Danny; Fiore, Jack; Ziv, Robert O.; Uy, Philip
PATENT ASSIGNEE-Night Vision Corporation
A dichroic type narrow-band-pass filter is used as a beamsplitter inside a night vision goggle eyepiece. The filter is combined with appropriately aligned polarizers and liquid crystal type shutter rotators movable between a P orientation and an S orientation to transmit center band and side band wavelengths of the normal view or night scene for recording, transmitting or enhancing. In the enhanced low light level mode, the intensified visible image presented to the user comprises a 40 degree circular image with a 30 degree by 22.5 degree rectangular display insert.
1. An image enhancement system for a night vision goggle system of the type having an image intensifier for converting incoming infrared and/or visible light to an intensified visible image for presentation via an eyepiece to the eyes of a user, said image enhancement system comprising: a pair of rotators; a pair of polarizers; and, a filter, said filter is positioned in alignment with said rotators and said polarizers; wherein central band light from the image intensifier is directed to the eye of the user when said polarizers and rotators are aligned in a first orientation, and wherein said central band light is directed away from the eye of the user when said polarizers and rotators are aligned in a second orientation.

4. Light emitting systems
US7166871
INVENTOR-Erchak, Alexei A.
PATENT ASSIGNEE-Luminus Devices, Inc.
Light-emitting systems, and related components, systems and methods are disclosed.
1. A light-emitting system including a light-emitting device that comprises: a multi-layer stack of materials including a light-generating region and a first layer supported by the light-generating region, wherein: a surface of the first layer is configured so that light generated by the light-generating region can emerge from the light-emitting device via the surface of the first layer; the surface of the first layer has a dielectric function that varies spatially according to a pattern; the pattern has a lattice constant and a detuning parameter with a value greater than zero; and the light-emitting device is configured so that, when light generated by the light-generating region emerges from the light-emitting device via the surface of the first layer, the light can emerge from the light-emitting system.

5. Day-night vision device
US20070013997-A1
INVENTOR-Zadravec, Dusan Rebstein
INVENTOR-Waelti, Felix Marbech
APPLICANT-VECTRONIX AG
In a day-night vision device according to the invention, it is intended that observations made via a day or night vision channel will be observed in a common receiving channel or via an eyepiece unit as a day or night image, by forming and arranging a deflection means in such a way that radiation from the day or night vision channel can be deflected by the same deflection means into the common receiving channel. In particular, it is also intended that further images, such as thermal images, can be guided to the observer and can be superposed, in particular fused, with the day or night image.

6. Multifunctional observation device
US20070014003-A1
INVENTOR-Zadravec, Dusan Rebstein
APPLICANT-VECTRONIX AG
In an observation device according to the invention, it is possible to coordinate a multiplicity of functions with the device by using and exchanging optical modules. By means of existing optical components in the observation device, transmitted and/or received beams of the modules can be reflected in and/or reflected out. For example, field glasses, binoculars and measuring glassed can be equipped according to the invention with modules. The modules can be produced for special purposes, can be carried in particular as convenient units and can be inserted into the device and removed therefrom an can be exchanged. An optical module may be, for example, in the form of a camera, graphic display or IR laser. The modular multifunctional observation device according to the invention can be designed as a compact and light device by using optical components already present in the basic system.

7. Multi-function, day/night observation, ranging, and sighting device
EP1018142-B1
INVENTOR-SALDANA, Michael, R.
PATENT ASSIGNEE-Litton Systems, Inc.
1. A day/night viewer apparatus, comprising: an objective lens (28) receiving light from a distant scene; an eyepiece lens (30) providing an image of the distant scene; an image intensifier tube (50) receiving light via said objective lens (28) and responsively providing a visible image available at said eyepiece lens (30), said visible image having a brightness level; characterized by further comprising a power supply circuit (52) adapted to selectively provide in a first mode of operation a variable differential voltage to a microchannel plate (50b) of the image intensifier tube (50), and adapted to alternatingly supply in a second mode of operation differing voltage levels in a duty cycle to a photocathode (50a) of the image intensifier tube (50); whereby the brightness of the image provided by the image intensifier tube (50) to a user of the device may be controlled selectively by operating said power supply circuit (52) alternatively in one of said first and second modes of operation. 2. The apparatus of Claim 1 further including manually-adjustable means for allowing a user of the device to adjust said duty cycle to be applied in said second mode of operation. 3. The apparatus of Claim 1 further including a voltage converter circuit providing said differential voltage to said microchannel plate (50b) of said image intensifier tube (50), and an automatic brightness control circuit effective to reduce said differential voltage in response to a current signal from said image intensifier tube (50). 4. The apparatus of Claim 3 further including a laser light source for projecting a pulse of laser light (22) into the scene, a laser range finder control logic circuit (150), said laser range finder control logic circuit (150) having an input to said voltage converter circuit effective upon operation of a laser range finding command signal to temporarily discontinue reduction of said differential voltage on said microchannel plate (50b) during a certain time interval.

8.Vision system with eye dominance forced to fusion channel
US07158296
INVENTOR-Schwartz, II, Sheldon; Reed, Matthew W.
PATENT ASSIGNEE-Insight Technology, Inc.
A fusion vision system has a first eyepiece through which a fused viewable image is larger than an image viewed through a second eyepiece to help the operator more easily view the fused image in their brain. The fusion vision system may employ image intensification and thermal imaging capabilities.
1. A fusion vision system, comprising: a housing; a first channel coupled to the housing for processing information in a first range of wavelengths; a second channel coupled to the housing for processing information in the first range of wavelengths; a third channel coupled to the housing for processing information in a second range of wavelengths; an image combiner for combining information from the first channel with information from the third channel to generate a fused image; a first eyepiece aligned with the fused image; and a second eyepiece aligned with the second channel, wherein the fused image viewed through the first eyepiece is larger than an image viewed through the second eyepiece.

Alan Harrison is a Nerac Patent Analyst. Nerac's Intellectual Property Solutions provide a practical understanding of the IP landscape, helping organizations to make informed decisions about R&D planning and business strategy development. Nerac analysts work with clients in the following critical areas:
  • Patentability and Invalidity
  • Patent Portfolio Analysis
  • Commercialization Strategy
  • White Space Analysis