GB2548836A

GB2548836A - A night vision attachment for an optical rifle scope

Info

Publication number: GB2548836A
Application number: GB1605202.9A
Authority: GB
Inventors: Nicos Adamou Adam
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-03-29
Filing date: 2016-03-29
Publication date: 2017-10-04
Also published as: GB201605202D0

Abstract

A night vision attachment for coupling to the viewing end of an optical rifle scope S is disclosed. The attachment unit is an add-on housing 10 that includes a deflector 11 such as a mirror or a prism, a camera 12 with infrared capabilities, and a view-finder 14, which may receive an image from the camera. The distance of the path of light travelled from the scope S to the camera 12 corresponds to a defined eye relief distance R of the scope S, which is determined during set up. The attachment can be fitted to a regular day-scope. The invention provides the advantage that the shooter does not need to adjust his shooting position, since the eye relief R will be unchanged and the eye E of the shooter remains in line with the scope S due to the position of the view finder 14. The eye relief of the viewfinder provides sufficient distance to the eye of the user to avoid impact during recoil of the rifle.

Description

A NIGHT VISION ATTACHMENT FOR AN OPTICAL RIFLE SCOPE

The present invention relates to a night vision attachment for an optical rifle scope. Particularly, the invention is an add-on which enables the user of a rifle equipped with a regular daytime optical scope to convert/adapt it for night time use. It is intended that the invention can be implemented without needing to adjust the daytime scope either before or after the addition of the night vision attachment.

BACKGROUND TO THE INVENTION

There are currently a number of solutions that enable night vision capabilities for a regular daytime optical rifle scope. The present invention is concerned with such devices and not a dedicated night vision rifle scope or monocular per se.

By way of background, modern night vision solutions (for rifle scopes or otherwise) tend to fall into one of two categories, namely a digital camera with infrared capability or GEN 1, 2 and 3 class night vision which utilise a light sensitive chemical.

Digital night vision add-on solutions use a digital video camera with its IR filter removed, making it sensitive to infrared (IR) wavelengths. The wavelength range typically extends from the nominal red edge of the visible spectrum at 700 nanometers (frequency 430 THz) to 1 mm (300 GHz), although people can see infrared up to at least 1050 nm in experiments. Most of the thermal radiation emitted by objects near room temperature is infrared. A display screen is used in conjunction with the camera, usually an LCD monitor/view finder to display the scope's sight picture and reticle to the shooter. The apparatus prevents direct/naked viewing through the scope's optics and relies on the screen display. GEN 1, 2 and 3 add-on systems are again attached to the back of the scope but, instead of a camera, use a photocathode, i.e. a negatively charged electrode in a light detection device such as a photomultiplier or phototube that is coated with a photosensitive compound.

Low level light is enhanced and amplified (including IR) for viewing by the shooter. Such systems cannot be used during the day and, due to cost, are not very popular as an add-on system.

The more general problem associated with prior art night vision attachments is that, once the device is attached to the rifle scope, they interfere with the natural shooting position of a user. It is well known that the shooting position of a rifle is very important if accuracy and familiarity with the rifle is to be maintained. Most rifle scopes have an eye relief that is inherently linked with this shooting position; specifically, a set distance is designed into the optics of the scope which keeps the eye of a user out of contact with the scope itself. The eye relief ensures that recoil from firing the rifle does not cause an impact with the eye area of a shooter. A shooter/user will set up a rifle scope for an optimum shooting position, where the eye relief is the perfect distance from the back of the scope which in turn provides the best sight picture of a chosen target through the scope. If an add-on device for night vision requires the user to adjust their scope or shooting position, then this is a distinct disadvantage because the shooting experience will be different depending upon use during the light of day or dark of night/dusk/dawn.

Figures 1-3 illustrate prior art optical rifle scope arrangements. Particularly, Figure 1 shows a regular daytime scope S set up with an eye relief R which is comfortable for the user to view the scope at a convenient eye level E. The set-up of a rifle scope is not part of the present invention as it is assumed that a skilled person is familiar with how to optimise scope position.

Figure 2 illustrates a prior art night vision attachment where a digital camera C is fitted within a scope extension X that substantially corresponds to the eye relief distance R shown in Figure 1. The camera C is electrically connected to a liquid crystal display L which is mounted above scope S and viewable by a user from an eye position E. However, it is clear from this configuration that the eye position E is different from the use of the unmodified scope S from Figure 1. An eye E, according to Figure 2 with night vision attachment, must view from a higher position and is also further back than the corresponding position of Figure 1, where there is no night vision attachment in place.

Likewise, Figure 3 illustrates a night vision add-on embodiment where the camera C and corresponding electronic view-finder V are in-line with scope S but, necessarily, the total scope extension X must be longer than the scope eye relief R in order for an image (modified for night vision) to be viewable by eye E. Only a very short eye relief is provided between eye E and the view-finder V (which could be dangerous during recoil). While eye E is located in-line with scope S the total distance is much further away from the comfortable scope eye relief R as illustrated in Figure 1.

In addition to the prior art described above and illustrated herein, GB2448314 describes a further embodiment of night vision attachment using a series of lenses and mirrors to modify the image path before it reaches a camera. This solution is highly elaborate in order to achieve its purpose of adding substantially less length to the back of the telescopic sight but, due to the complexity, is not particularly practical.

Likewise, the prior art solutions of Figures 2 and 3 are functional, but do not provide the familiarity for the user that they have when using a daytime scope without attachment.

SUMMARY OF THE INVENTION

The present invention seeks to mitigate at least some of the disadvantages evident from the prior art. Particularly, a night vision attachment according to the invention should conveniently provide a rifle system that can be adapted for night use, without the need for adjustments to the day scope set-up or compromise to the shooting position.

In one broad aspect of the invention there is provided a night vision attachment for coupling to a viewing end of an optical rifle scope according to claim 1. This includes a light deflector located in the path of light travelling through the optical rifle scope, a sensor located in the path of light reflected/deflected from the light deflector and a view-finder located in line with the viewing end of the optical rifle scope; wherein the light deflector and sensor are configured such that the total distance for light travelling from the viewing end of the scope to the sensor, via the light deflector, is substantially equivalent to a defined eye relief distance for the optical rifle scope. The eye relief distance is determined during set up and, in practice, the attachment can be fitted to a regular dayscope without needing additional adjustment to the shooting position.

Compared to prior art such as GB2448314 the present invention embodies the idea of having an imaging sensor, preferably in the form of a camera, mounted out of line of the scope, receiving an image reflected using one mirror (or prism) only. The camera is positioned such that the total distance from the scope to the camera, via the deflector, matches the normal eye relief of the scope. The system of the invention is clearly less complex and, hence, more desirable than the prior art, particularly as it is able to be used without any adjustments to the regular optical rifle scope position and associated familiarity of use. Furthermore, there are less stages of reflection each of which, in the prior art, can potentially distort the image.

Preferably the deflector, i.e. a means of altering/deflectinga light path, is a mirror mounted at 45 degrees to the incoming light/image source, which reflects the image to a digital camera or equivalent night vision sensor positioned perpendicularly to the scope's line of sight. However, other deflection angles could be considered so long as the total size of the housing and its associated components do not extend beyond the intended eye relief distance. Essentially, the invention functions to save valuable space behind the scope to accommodate a shooter's normal shooting position and eye relief. There will still be a sufficient distance between the view finder/display device and an eye of a user to avoid impact during recoil of the rifle.

In the preferred embodiment the image sensor is a digital camera, however, alternative forms may be possible, including implementation of photocathode technology or other methods of light amplification. For example, a photosensitive tube can be located in the path of light between the deflector and camera. Such a modification may be more appropriate for a military application because an infrared torch is not needed to light up the target area.

Preferably the image sensor or electronic view finder display is configured to invert the reflected image so that it accurately represents the orientation of the scope optical view. The attachment is intended to have the camera focused on the original cross hair settings set by the user in their day time shooting settings.

The effective eye relief to the digital camera is maintained for a clear image by locating the camera at a defined distance from the mirror. Both the distance from the end of the scope to the mirror and the mirror to the camera lens sum to an amount that is substantially equal or corresponds to that of the scope's designed eye relief. The attachment components are preferably mounted in a housing that may be configurable to adjust the relative distance of the deflector and/or digital camera in order to tailor it to a particular user and ensure that minimal disruption is experienced by the user when attaching or detaching the device from the regular optical rifle scope set-up. The housing may incorporate an extension tube which is telescopic (i.e. extendable) or interchangeable with longer/shorter units in order for the night vision attachment to be customised. As mentioned, the display device, in the form of an electronic view-finder, is located in alignment with the centre of the scope to maintain an accurate representation of the shooter's eye position.

It is expected that, because each scope eye relief and objective size can vary between manufacturers, an adaptor will be provided specific to a particular scope dimension. The adaptor is able to detachably fix to the main add-on housing or be part of the extension tube in order for the housing design itself to be universal.

By way of example, most eye relief designs for a given rifle scope would be at least 80mm, therefore, the size of the housing according to the invention is preferably 70mm or less in order to give some clearance (minimum 10mm) between the eye of a shooter and the view finder. Preferably the depth of the housing is between about 30 and 50mm, with the remainder of the scope's eye relief measurement made up by an extension tube/adaptor.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates a side view of an optical rifle scope set up with a natural shooting position, well known in the art;

Figure 2 illustrates a night vision attachment with top-mounted LCD screen as known in the prior art;

Figure 3 illustrates a further embodiment of night vision attachment known in the prior art;

Figure 4 illustrates an optical rifle scope configured with a night vision attachment according to the present invention; and

Figure 5 illustrates a further detailed view of components from the night vision attachment according to Figure 4.

DETAILED DESCRIPTION OF THE INVENTION A night vision attachment according to the present invention is illustrated by Figures 4 and 5. Particularly, a housing 10 is positioned for attachment to an optical rifle scope S which is typically intended for daytime use. Rifle scope S is the same as, or comparable to, the rifle scopes illustrated by Figures 1-3 and is not part of the present invention.

According to the invention a deflector, in the form of mirror 11, is mounted within housing 10 directly in the path of the light/image passing through the optics of scope S. This light path is reflected/deflected toward an image sensor, in the form of camera 12, creating a deflected path. In the preferred form camera 12 is located directly above mirror 11, but other configurations would be possible, depending on the angle of the deflector 11 and other practical considerations for construction of housing 10.

In the illustrated form camera 12 is located to capture a perpendicularly deflected image due to the 45 degree angle of deflector 11. Camera 12 is typically a digital video camera with its IR filter removed, making it sensitive to IR wavelengths. The camera is electronically connected to a view-finder 14 which is positioned in the same line of sight as the scope S during normal use. The image displayed by view-finder 14 is representative of the image received at the full eye relief distance R since it is intended that the total path of light to the camera is the same as R. The distance between the view-finder 14 and an eye E of a user should be configured to be as comfortable as possible for the user. An image displayed on view-finder 14 can be manipulated either optically or digitally so the user's eye E can accurately make out the image. Furthermore, the image should be inverted (by camera or display electronics) since it has undergone a single reflection and will be a mirror image when received by sensor 12. The image size may not necessarily be exactly in correspondence with the unprocessed image through the scope, but the content will be equivalent and it will be in focus so that a shooter can see what they are aiming at, including the reticle. Particularly, the night vision attachment according to the invention should not require any adjustment to the scope reticle (cross hairs) focus. The attachment is intended to have the camera focused on the original cross hair settings set by the user in their day time shooting settings.

Housing 10 may be formed integrally with or have a separable extension tube 15 that detachably couples with a viewing end of scope S. Extension tube 15 preferably includes an adaptor end 16 and a proprietary end 17 for connection to the housing 10. Preferably tube 15 is a simple plastic moulded cylinder that can be provided with the adaptor end 16 best suited to couple with a particular scope S. Attachment could be by way of clamping or an interference fit with a rubber seal, so long as a secure fit is achievable. Tube 15 may include further internal optics (or light enhancement), although it is generally desirable that this component be as simple as possible to reduce expense/complexity.

Extension tube 15 could be telescopic for adjustability or, as illustrated, be provided as a removable/replaceable unit. In this way various interchangeable tubes 15 can be supplied in order to match a required eye relief distance R.

In one form of the invention, not illustrated, the view-finder 14 may be "flipped-up" in order to provide visual access into housing 10. Mirror 11 may also pivot out of the way in order to provide an unobstructed view of scope S. In other forms, mirror 11 may be part of a prism that is reflective on its angled surface and transparent so the eye E can see through toward scope S. In yet other forms the mirror may be a "one/two-way" mirror that is transparent when viewed from one side. Such an effect is usually possible when one side of the mirror is dark. For example, the side adjacent view-finder 14 will be in darkness (enclosed in housing 10) in normal use such that the surface receiving light A is reflective, but when the housing is opened, adjacent view-finder 14, mirror 11 becomes transparent so that scope S can be seen from position E.

The design dictates that if the path distance of light from scope to camera is equivalent to R then, when the extension tube 15 for a specific scope is fixed to the night vision attachment (housing 10), the overall space occupied by the add-on components will be less than the normal eye relief R for the shooter. The total designed depth of the housing 10 plus its own eye relief for viewing of the view finder 14, safely distant to avoid recoil damage, will be less than the average eye relief R of most scopes on the market (in practice about 80mm or more) meaning that, so long as the correct tube 15 and adaptor 17 is chosen, the user's position for both daytime and night time shooting can be matched.

Figure 5 illustrates a closer view of the components within housing 10. It can be seen that a path A from the leading edge of the housing, combined with the distance B from deflector 11 to camera 12 is the same effective distance as the total depth of the housing C (including to trailing edge of view finder 14) combined with the eye relief D of the attachment: (A+B) = (C+D). One could also observe that the straight line distance between the eye of a user E and the deflection point of deflector 11 is the same as the distance from the deflection point to the sensor 12.

These distances are the same or less than the eye relief R of a typical scope as per Figure 1. The shortfall in the distance is made up by the extender tube 15 and adaptor which occupies a space X according to Figure 5, i.e. in total: R = (X + C + D) or R = (X + A + B).

The housing and its eye relief is intended to be a "one-size-fits-all" design where the only modification is choosing the correct extender tube 15 and adaptor dependent on the rifle scope. Guidance for choosing the correct extension/adaptor can be tabulated at point of sale.

The present invention can be implemented using available materials and technologies. The camera and view-finder will likely be powered by a battery pack (not illustrated) incorporated into the housing and/or extension tube. Modern technologies can ensure that the combined weight of the housing/adaptor is minimal, so as to avoid undue fatigue for the user during handling/shooting. Although, in many situations, the user may be in a prone position and/or the rifle is resting upon a stabilising surface such that any added weight has minimal practical effect on use.

Claims

CLAIMS:

1. A night vision attachment for coupling to a viewing end of an optical rifle scope, including: a deflector located to define a first distance from the viewing end of the optical rifle scope, in the path of light travelled therethrough; a sensor located to define a second distance from the deflector in the path of light reflected/deflected therefrom; and a view-finder located in line with the viewing end of the optical rifle scope; wherein a sum of the first distance and second distance corresponds to a defined eye relief distance for the optical rifle scope.

2. The night vision attachment of claim 1 wherein the deflector, sensor and viewfinder are mounted within or on a housing.

3. The night vision attachment of claim 2 wherein the deflector is a mirror mounted within the housing.

4. The night vision attachment of claim 2 or 3 wherein the sensor is a camera, capable of sensing and transmitting infrared light, mounted within the housing out of line with the optical rifle scope.

5. The night vision attachment of claim 3 and 4 wherein the mirror is mounted at 45 degrees to the path of light from the optical rifle scope and the camera is mounted perpendicularly to the path of light from the optical rifle scope.

6. The night vision attachment of claim 2 wherein the night vision attachment has a view finder eye relief which, when combined with a depth dimension of the housing, is less than the defined eye relief distance of the optical rifle scope.

7. The night vision attachment of any preceding claim wherein a light amplification means is located in the path of light between the deflector and the sensor.

8. The night vision attachment of any preceding claim wherein the sensor and/or view finder are configured to invert a reflected image.

9. The night vision attachment of any preceding claim wherein the sensor and view finder are configured for electronic connection and there is only one reflection operation between the optical rifle scope and eye of a user.

10. The night vision attachment of any preceding claim, configurable to adjust the relative distance of the deflector and/or sensor

11. The night vision attachment of claim 6, including an extension portion, extending from the housing and in line with the optical rifle scope, for coupling to the viewing end of the optical rifle scope, wherein the length of the extension portion corresponds to the shortfall between the combined view finder eye relief distance and depth dimension of the housing.

12. The night vision attachment of claim 11 wherein the extension portion is a telescopic tube or an interchangeable tube intended to be swapped for another tube of different length.

13. The night vision attachment of claim 11 or 12 wherein the extension portion includes an adaptor for coupling to the viewing end of a particular manufacturer's type of optical rifle scope.

14. The night vision attachment of claim 13 wherein the adaptor includes a clamp or interference fit/seal for detachable coupling of the housing from an optical rifle scope.

15. The night vision attachment of any preceding claim wherein the view finder is removable or pivotable in order for visual access to the viewing end of the optical rifle scope.

16. The night vision attachment of claim 15 wherein the deflector is also movable to remove obstruction or is capable of becoming at least partially transparent for visual access to the viewing end of the optical rifle scope.

17. A method of modifying an optical rifle scope for use in the dark, including: arranging a deflector at a first distance from a viewing end of the optical rifle scope, in the path of light travelled therethrough; arranging a sensor at a second distance from the deflector in the path of light reflected/deflected therefrom; and arranging a view-finder, behind the deflector, in line with the viewing end of the optical rifle scope; wherein the deflector and sensor are arranged such that a sum of the first distance and second distance corresponds to a defined eye relief distance for the optical rifle scope.

18. The method of claim 17 wherein the operating position of a user's eye, relative to the deflector, is at a distance equivalent to the distance between the deflector and the sensor.

19. The method of claim 17 or 18 wherein the sensor is focused on cross hairs of the optical rifle scope as set by the user for day time shooting.