JP7623443B2 - Sighting scope having illuminated sight and thermal imaging camera - Google Patents

Description

The field of the invention is that of aiming scopes, including thermal imaging cameras and illuminated sights.

To carry out his various missions with his weapons, the infantryman needs:
- Day and night firing capability, requiring precise aiming to best utilize one's weapon, ideally for effective firing beyond 300 meters;
- Rapid targeting in dynamic combat situations;
- Maintaining good situational awareness to respond to any threat that may occur on the battlefield during the day and at night. This situational awareness especially involves maintaining a wide field of view that encompasses the surrounding space.
- the ability to "decamouflage" or perceive threats both during the day and at night;
- discrimination reflected through the absence of light emission from the sighting elements, especially at night;
- no bore sight setting operation to switch from daytime to nighttime (and vice versa) in order to save time and ensure the reliability of the sight;
- Mobility and durability, requiring equipment that is as light and compact as possible.

These needs are reflected by the strong demands placed on the targeting components fitted to the assault rifles that infantrymen are provided with. In practice, these requirements are only partially met, and not at all, by a single piece of compact, lightweight equipment.

The usual solution to ensure alignment in an assault rifle is as follows: For daytime alignment, the weapon basically includes an eyepiece-front sight assembly. This assembly is simple, robust, and inexpensive, but offers little accuracy.

The weapon may also include the following for daytime targeting:
- an illuminated sight, i.e. an optical assembly that allows a luminous symbol or dot to be superimposed outside the aiming axis. This illuminated sight can possibly be associated with switchable magnification optics. By way of example, the magnification is 3.
- Laser pointer.
- Daytime magnifying scope.
For nighttime targeting, the weapon may include:
- Laser pointer.
- A targeting scope with an optically intensified targeting scope called an "IL" scope.
- An infrared targeting scope called an "IR" scope.
- A light intensifier or infrared adapter or "clip-on" placed upstream of the daytime aiming scope.
- Aiming equipment including night glasses associated with an illuminated sight fixed to the weapon.

Each of these known solutions has advantages and disadvantages, however, none fully addresses the overall need identified above.

The illuminated sight solution is particularly well-considered because it provides excellent accuracy while allowing aiming and firing with both eyes open, and allows for eye positioning relatively far from the illuminated sight optics, preserving excellent awareness of the overall situation as long as the eyes do not have to be close to the eyepiece. The shooter can keep both eyes open, and the illuminated sight conveys the landscape without magnification.

Aiming with a laser pointer, which is widely used especially at night, is very advantageous because it allows rapid shooting in dynamic combat without the eye having to be aligned behind the sight or even having to shoulder the weapon in extreme situations. On the other hand, a laser pointer remains unthinking, especially at night. Even if it is a pointer that emits near-infrared light, it is easily detectable even with certain equipment that uses night vision glasses or cameras sensitive to near-infrared light.

Whether the aiming scope is a daytime scope or a nighttime scope, aiming scopes with thermal enhancement or thermal infrared generally offer the advantage of accuracy, especially due to their magnification. They present the disadvantage of requiring the eye used for aiming to be placed close to the eyepiece. Furthermore, the user cannot use the other eye for the overall picture. This action takes a certain amount of time, which constitutes a loss of efficiency in dynamic combat. Moreover, the shooter is momentarily cut off from his environment and may then not notice new threats. Finally, at night, if wearing night vision glasses, the combatant must remove his night vision glasses to be able to accurately place his free eye behind the aiming scope, which also represents an additional delay in the battle and a disconnection of the combatant from the environment.

Infrared or thermal imaging sights exhibit the same drawbacks but offer a few significant advantages, namely night vision, including in complete darkness, improved vision in the fog and smoke of battle, and especially the ability to "decamouflage" any hot targets.

It is possible to juxtapose several systems within a single piece of equipment to attempt to provide an appropriate response. For example, as can be seen in FIG. 1, some aiming equipment items combine an IL or IR aiming scope topped by an illuminated sight. In this case, the scope includes a thermal imaging camera and a viewing device. The thermal imaging camera includes a focusing lens 1 and a light-sensitive receiver 2. The viewing device includes a microdisplay 3 and an eyepiece 4. The illuminated sight includes a light-emitting symbol 5 and optics 6 for collimation and superimposition with direct vision 7.

These solutions result in relatively bulky equipment that offers a juxtaposition of functions without the functions being combined. At any given moment, the user must choose to use either the illuminated sight or the scope, and thus does not benefit from the cumulative advantages of both systems. In the case of a system that associates a thermal infrared scope and an illuminated sight, the user must choose between benefiting from the rapid targeting and situational awareness provided by the illuminated sight, or benefiting from the decamouflage and night vision provided by the thermal imaging scope.

In summary, existing solutions based on a single principle of the illuminated sight, pointer or scope type do not meet all of the infantryman's needs to shoot in any situation. Solutions that juxtapose two principles in the same equipment, for example an illuminated sight and a thermal imaging scope, allow to pool certain advantages rather than to benefit from all of them simultaneously. Moreover, these systems are bulky and heavy. They do not meet all of the needs identified above.

The scope according to the invention does not have the above mentioned drawbacks. Indeed, several images from different sources are perceived by a single eyepiece of the illuminated sight type. Thus, some of the requirements of this type of equipment are guaranteed while retaining a reduced bulk. More specifically, the subject of the invention is a sighting or spotting scope comprising in a single mechanical structure a camera and a video microdisplay associated with the eyepiece, the eyepiece being characterized in that it uses an optical combiner arranged to superimpose the video microdisplay image on the external landscape.

Advantageously, the scope includes an illuminating symbol or dot and an optical device arranged to superimpose an image of the illuminating symbol or dot on the image of the video microdisplay and on the external landscape.

Advantageously, the optical chain consisting of the camera, the microdisplay and the eyepiece has a magnification of 1, so that the microdisplay image matches the image of the external landscape.

Advantageously, the optical combiner includes a planar semi-reflective surface inclined at approximately 45 degrees relative to the aiming or positioning axis.

Advantageously, the semi-reflective surface is incorporated into a splitter plate that includes two planar and parallel faces.

Advantageously, the semi-reflective surface is incorporated into a splitter cube that includes two planar and parallel faces, the normal to which may be parallel to the aiming or positioning axis.

Advantageously, the splitter prism includes a reflective concave mirror, the optical axis of which is perpendicular to the aiming or positioning axis, and the light beam from the video microdisplay is transmitted by the semi-reflective plate, reflected by the concave mirror and then reflected by the semi-reflective plate.

Advantageously, the splitter prism includes a convex input surface, the optical axis of which is perpendicular to the aiming or positioning axis and faces the concave mirror.

Advantageously, the optical combiner includes a "freeform" or diffractive type concave semi-reflective surface tilted relative to the aiming or positioning axis, and the eyepiece includes a convex mirror associated with the concave semi-reflective surface.

Advantageously, the optical device includes a splitter plate or splitter cube arranged in front of the video microdisplay, whereby the image of the luminous symbols or dots is combined with the video microdisplay by reflection or transmission through the splitter plate or splitter cube.

Advantageously, the camera is a thermal infrared or low light level camera.

The invention will be better understood and other advantages will become apparent on reading the following description, given in a non-limiting manner and from the accompanying drawings, in which:

1 depicts a prior art sighting scope-illuminating sight combination, previously discussed. 1 illustrates a perspective view of a targeting or spotting scope according to the present invention; 1 represents a manufacturing scheme for a targeting or spotting scope according to the present invention. 1 illustrates a first embodiment of an eyepiece according to the present invention. 2 illustrates a second embodiment of an eyepiece according to the present invention. 3 illustrates a third embodiment of an eyepiece according to the present invention. 1 illustrates an alternative embodiment of a targeting or spotting scope according to the present invention, including the generation of collimated luminous dots. 4 illustrates a fourth embodiment of an eyepiece according to the present invention.

Figure 2 shows a perspective view of the targeting and spotting scope according to the present invention. It essentially comprises two main subassemblies: a camera 10 and a viewing device 15 including an eyepiece with a microdisplay and an optical combiner. The optical combiner is mounted on top of the camera. The assembly of optical and electronic components is housed in an enclosed structure 80 that protects them from the external environment and impacts.

The structure includes a mechanical fastening interface 85 that allows the structure to be fastened onto a weapon equipped with a standard interface, such as a "Picatinny" rail or equivalent.

The structure also includes a set 87 of buttons and controls that allow, among other things, on/off control of the different functions of the equipment, video microdisplay brightness settings, electronic and mechanical muzzle sighting settings, electronic settings for superimposing the different images generated on the external landscape. It can be located on one of the two lateral reliefs of the scope. By way of example, in FIG. 2 the set includes three buttons located on the left lateral relief of the scope, and another button located on the left relief of the scope.

Figure 3 represents a first embodiment of a sighting or spotting scope according to the invention. For this and the following figures the following conventions have been adopted: optical or mechanical elements are represented by thick lines, light rays are represented by thin lines and the optical axis is represented by a dotted line. For clarity, only light rays on the optical axis are represented.

The camera is preferentially a thermal imaging camera consisting of an infrared lens 20 operating in the spectral band located between 8 μm and 12 μm and an infrared sensor 25 equipped with a microbolometer sensitive in the same spectral band.

The camera can also be a low light level camera implementing a low noise "CMOS" sensor ("CMOS" is an acronym for "Complementary Metal Oxide Semiconductor") or an "EB-CMOS" sensor ("EB-CMOS" is an acronym for "Electron Bombardment CMOS"). The camera can also be a "SWIR" camera ("SWIR" is an acronym for "Short Wave Infrared") that operates in the 1 μm to 2 μm spectral band, senses light from night lights, and also provides decamouflage capabilities.

The camera includes a power supply unit 40 housing a block of several battery cells or rechargeable batteries that can be placed behind the scope on the eye side to ensure the autonomy of the camera, as well as a power supply, sensor drive and image processing electronics 30.

The viewing device includes a microdisplay 50, an eyepiece 60 with an optical combiner 70, and the electronics required to power and drive the microdisplay.

This microdisplay 50 displays a video aiming reticle, possibly enhanced with sight correction elements or optical range finding symbols or scales. It also displays a thermal infrared image of the scene from a thermal imaging camera.

The microdisplay may be, for example, an "OLED" display ("OLED" is an acronym for "Organic Light Emitting Diode"), an "LCD" ("LCD" is an acronym for "Liquid Crystal Display"), or an "LCOS" display ("LCOS" is an acronym for "Liquid Crystal on Silicon").

The optical chain consisting of the camera, microdisplay and eyepiece has a magnification of 1, so that the microdisplay image matches the image of the external landscape. An optical combiner ensures perfect alignment of the microdisplay image on the external landscape.

Eyepieces with optical combiners have different possible embodiments.

In the first embodiment illustrated in Figures 4, 5 and 8, which show different optical eyepiece combinations, the optical combiner includes a planar semi-reflective surface tilted at 45 degrees to the aiming or positioning axis. This surface has no optical power.

This surface may belong to a semi-reflective plate with thin, flat and parallel faces, as seen in Figure 8.

As shown in Figures 4 and 5, this plate can be advantageously incorporated into a splitter cube that includes two planar and parallel faces in order not to introduce distortions on the external landscape. The normals to these faces can be parallel to the aiming or positioning axis.

Figure 4 represents a first eyepiece 61 including focusing optics and an optical combiner 71 with a splitter cube. The focusing optics form an image from the microdisplay 50 to infinity, which is superimposed by the optical combiner 71 on the external landscape. The optical combiner 71 includes an inclined plane semi-reflective plate 711 and two plane and parallel faces 712 and 713. As in the example, the focusing optics of Figure 4 includes three lenses 610, 611 and 612 and a plane return mirror 613 located between the second lens and the third lens. This mirror 613 allows the bulk of the focusing optics to be reduced. In an alternative embodiment, the mirror can be replaced by a total reflection prism. In this configuration represented in Figure 4, the optical combiner 71 reflects the image directly from the display to the observer's eye Y.

Figure 5 shows a second eyepiece 62 containing focusing optics and an optical combiner 72 with a splitter cube. In this configuration, the optical combiner has optical power on the microdisplay path. The optical combiner has no optical power on the direct transmission path. Thus, the number and size of lenses required for collimation are reduced. The eyepiece is simpler and less bulky.

The splitter cube 72 then contains a reflective concave mirror 722, whose optical axis is perpendicular to the aiming axis. Collimation of the light rays from the display 50 is ensured by a group of three lenses 620, 621 and 622 and a combiner 72. The light rays from the video microdisplay 50 pass through the group of lenses, are transmitted by a semi-reflective plate 721, are reflected by the concave mirror 722 and are then reflected again by the semi-reflective plate 721 towards the observer's eyes.

In this optical combination, as in the previous combination, the flat return mirror 623 allows to reduce the optical bulk of the eyepiece. In a variant embodiment, the splitter cube includes a convex input surface 723, whose optical axis is perpendicular to the aiming or positioning axis and faces the concave mirror 722. The function of this convex surface 723 is to avoid the total reflection seen by the eye that arises from the scene and is reflected by total reflection on this surface of the prism. This convex surface makes it possible to defocus these spurious images and push them back into the blind zone in the shooting position.

In a second embodiment shown in FIG. 6, the optical combiner 73 comprises a "freeform" or diffractive type concave semi-reflective surface tilted with respect to the aiming or positioning axis. A "freeform" surface is understood to mean a surface that does not have rotational symmetry. It can be defined in various ways.

In this configuration, the semi-reflective surface is tilted with respect to the optical axis at a significant angle, which may be about 40 degrees. In this case, the eyepiece 63 includes a convex mirror 632, which is also tilted with respect to the optical axis associated with the concave semi-reflective surface 73, as can be seen in FIG. 5. This mirror may also be a "freeform" or diffractive type surface. Finally, the eyepiece 63 includes a group of two lenses 630 and 631 forming a pair, a convex mirror 632, and a concave semi-reflective surface 73. If the group of lenses has a significant focal length, it is possible to place an optical beam folding device, which may be mirror-based or prism-based, between the display 50 and this group of lenses to reduce the bulk of the eyepiece.

In an important variant embodiment of the aiming and spotting scope according to the invention, the scope comprises a luminous symbol or dot and an optical device arranged to superimpose the image of the luminous symbol or dot on the image of the video microdisplay and on the external landscape. The optical device then comprises a splitter plate or splitter cube arranged in front of the video microdisplay, whereby the image of the luminous symbol or dot is combined with the video microdisplay by reflection or transmission through the splitter plate or splitter cube.

In its basic version, the light-emitting dot is generated by a light-emitting diode placed in front of a feed hole, which is arranged in the focal plane of the eyepiece so as to be superimposed on the microdisplay image. This dot is generally red in colour. The light-emitting dot is fixed on a translation adjustment mechanism in the focal plane in order to allow the user to carry out a muzzle aiming adjustment of the aiming axis embodied by the light-emitting dot relative to the firing axis of the weapon. The display reticle and the red dot constitute two alternative solutions for indicating the aiming axis of the weapon, the red dot being a simple solution with very low consumption. The video reticle makes it possible to generate patterns of various sophisticated shapes, including, for example, optical distance measuring symbols of people or vehicles, ensuring proper distance measurement.

The "red" dot therefore constitutes an optional supplement to the video microdisplay. It also allows for a low-power deactivation mode when the microdisplay and thermal image are not in operation, for example to conserve the electrical energy of the scope.

A first example of the implementation of this variant embodiment is shown in FIG. 7. A splitter cube 90 including a planar semi-reflective plate 91 is placed between the microdisplay 50 and the first lens of the eyepiece. The eyepiece has the configuration of the eyepiece 60 of FIG. 3. A red dot 95 is positioned such that its image is combined with the microdisplay by reflection at the semi-reflective plate 91.

A second exemplary embodiment is represented in FIG. 8. In this example, the eyepiece 64 includes an optical component 640 arranged between the microdisplay 50 and the splitter cube 900. An identical optical component 640bis is also arranged between the red dot 95 and the splitter cube 900. The splitter cube is an assembly of two prisms 901 and 902, whose common surface 910 includes a semi-reflective treatment. In the case of FIG. 7, the prism 902 operates by total internal reflection. The eyepiece part therefore includes, in this order, the optical components 640 and 640bis, the splitter prism 900, the total reflection prism 641 that ensures the folding of the beam, and the semi-reflective plate 73 and pair 642.

It should be noted that it is easily possible to adapt the eyepiece with the freeform plate of FIG. 6 to produce a red dot. For this purpose, it is sufficient to place a splitter cube or any other prism assembly between the microdisplay and the lens.

The aiming scope according to the invention can include a supplementary modular optical system that allows to modify the perception of the external landscape. Thus, for example, a magnifying afocal optical component with a magnification of 3 can be placed downstream of the optical combiner. Similarly, an optical module that is invariant with respect to magnification and optical intensifier axial deflection can be placed upstream of the combiner. The user thus perceives both an intensified image and a thermal image of the external landscape.

The first advantage of the scope according to the invention is that it adds decamouflage capabilities to illuminated sights for daytime aiming, while preserving the ergonomic qualities of illuminated sights, which provide a large eye print, do not hide the peripheral vision and allow the target to be acquired with both eyes open. The user has a directional image of the scene in the window of the sight, on which is superimposed an optical reticle embodying the firing axis of the weapon on the one hand, and a video image of hot targets present in the scene and which may pose a threat on the other hand. The exclusive display of hot targets of human body temperature, by eliminating the background of the scene, is ensured by conventional algorithms used in thermal imaging, especially in IL/IR fusion systems. These algorithms are well known to those skilled in the art. The combatant thus benefits from a combined view between the direct view of the scene and the thermal infrared view of the target, on which appears an optical reticle indicating the firing axis of the weapon if the combatant aims at this target.

The second advantage of this scope is that it allows infrared aiming at night in a manner that can be achieved with the ergonomics of an illuminated sight, i.e., unity magnification, large eye print, eyes open aiming, rather than a traditional thermal imaging sight.

A third advantage is that at night, the combatant can see through the illuminated sight by using light-intensifying night vision glasses that can be provided to him, which are fixed on his head or on his headset and are thus held in front of his eyes. He then benefits from the perception of the night scene over a wide field of view that is the field of view of the night vision glasses. This field of view is typically 40°. Furthermore, he benefits from an infrared vision of the scene around the reticle that defines his aiming axis. He then benefits from both situational awareness through the night vision glasses that provide a wide field of view that he can use with both eyes open, and from an image of the target that is decamouflaged in thermal infrared.

The combatant therefore has at his disposal a dual image combination system: direct and thermal infrared vision during the day, optical intensification and thermal infrared at night. This is effective without the addition of specific night vision glasses, simply by using the night vision glasses already available in the military. This double benefit, obtained from a single lightweight and compact module, is added to the advantage of having the ergonomics of the illuminated sight type that allows rapid aiming with both eyes open, during the day as well as at night, while retaining an excellent perception of the environment at each moment, which perception is beneficial for the responsiveness that allows to obtain an advantage in dynamic combat situations and in combat situations.

Claims (11)

A camera (10);
a video microdisplay (50) for displaying the image of the camera (10);
A luminous symbol or dot (95);
an optical device (90) arranged to overlay an image of said luminous symbols or dots on an image of a video microdisplay;
1. A sighting or spotting scope comprising in a single mechanical structure (80) an eyepiece comprising, in this order, an optical device, at least one group of lenses, and an optical combiner (70) arranged to superimpose an image of said video microdisplay and an image of said luminous symbol on an external landscape,
A luminous symbol or dot is located in the focal plane of the eyepiece to provide an aiming axis;
the aiming or spotting scope is configured to allow a user to perform muzzle sighting adjustments of the aiming axis relative to the firing axis of the weapon such that the position of the luminous symbol or dot (95) is translationally adjustable in the focal plane of the eyepiece;
Aiming or spotting scopes are
a mode in which the video microdisplay is powered on and configured to display at least a reticle, and the luminous symbol or dot (95) is powered off;
- A targeting or spotting scope that is configured to operate in different modes, including a low power deactivation mode in which the camera and video microdisplay are powered off while the luminous symbol or dot (95) is powered on. The aiming or spotting scope of claim 1, characterized in that the optical chain consisting of the camera, the microdisplay and the eyepiece has a magnification of 1 and the image on the microdisplay corresponds to an image of the external landscape. The aiming or spotting scope of claim 1 or 2, characterized in that the optical combiner includes a planar semi-reflective surface (711) inclined at 45 degrees to the aiming or spotting axis. The sighting or spotting scope of claim 3, characterized in that the semi-reflective surface is incorporated into a splitter plate that includes two planar and parallel surfaces. The aiming or spotting scope of claim 3, characterized in that the semi-reflective surface is incorporated into a splitter cube (71, 72) that includes two planar and parallel faces. The aiming or spotting scope of claim 5, characterized in that the splitter cube includes a reflective concave mirror (722) whose optical axis is perpendicular to the aiming or spotting axis, and the light beam from the video microdisplay is transmitted by the semi-reflective surface, reflected by the concave mirror, and then reflected by the semi-reflective surface. The aiming or spotting scope of claim 6, characterized in that the splitter cube includes a convex input surface (723) whose optical axis is perpendicular to the aiming or spotting axis and faces the concave mirror. The aiming or spotting scope of claim 1 or 2, characterized in that the optical combiner includes a "freeform" or diffractive type concave semi-reflective surface (73) tilted with respect to the aiming or spotting axis, and the eyepiece includes a convex mirror (632) associated with the concave semi-reflective surface. The aiming or spotting scope of claim 1, characterized in that the optical device includes a splitter plate or splitter cube (90) arranged in front of the video microdisplay, whereby the image of the luminous symbol or dot is combined with the video microdisplay by reflection or transmission through the splitter plate or splitter cube. The targeting or spotting scope according to any one of claims 1 to 9, characterized in that the camera is a thermal infrared camera. A targeting or spotting scope as claimed in any one of claims 1 to 9, characterized in that the camera is a low light level camera.

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