Improved sighting or viewing telescope

Abstract

Disclosed is a sighting or viewing telescope having a sight or viewing axis and comprising, in a mechanical structure (SM): - a camera (Cl), - a first video micro-display (MA1) displaying an image of the external landscape acquired by the camera, said image being referred to as first object, - a lens (OC) associated with the first video micro-display and forming a first infinity image of the first object, - a second video micro-display (MA2) displaying a second object - a combining optical device (SC) which is arranged optically downstream of the lens and is adapted to form an infinity image of the second object, referred to as second image, and to superimpose the first and second images on the external landscape.

Description

DESCRIPTION Title of the invention: Improved sighting or observation telescope Domain

[0001] The field of the invention is that of shooting glasses, in particular reflex sights, which allow a reticle to be superimposed on the scene being observed. Previous technique:

[0002] To accomplish his various missions with his weaponry, the infantryman has the following needs: - Ability to fire day and night, requiring precise aiming to make the best use of the weapon, ideally for effective shooting beyond 300 meters; - Rapid aiming in dynamic combat situations; - Maintaining a good situational awareness to deal with any threat that may arise on the battlefield, day or night. This situational awareness notably involves maintaining a wide field of vision encompassing the surrounding area; - Ability to "uncamouflage" or perceive threats, day and night; - Discretion, which is reflected in particular at night by the absence of light emission from the sighting devices; - No adjustment operation for the aiming mechanism to switch from day to night aiming and vice versa, in order to save time and ensure the reliability of the aiming; - Mobility and endurance, which requires equipment that is as light and compact as possible.

[0003] These needs translate into stringent requirements for the sights equipping the assault rifle issued to the infantryman. In practice, these requirements are only partially met and not with a single piece of equipment that is both compact and lightweight.

[0004] The following are common solutions for aiming an assault rifle. For daytime aiming, the weapon comes standard with a rear sight and front sight assembly. This assembly is simple, robust, and inexpensive, but offers limited accuracy.

[0005] The weapon may also be equipped for daytime aiming with a clear sight (or "reflex" sight), that is, an optical system that projects a symbol or illuminated dot onto the outside of the target along the line of sight. This clear sight may optionally be combined with a switchable magnifying optic. It may also include a laser pointer and a daytime magnifying scope.

[0006] For night aiming, the weapon may include: a laser pointer, a light-intensifying scope known as "IL", an infrared scope known as "IR", a light-intensifying or infrared adapter or "Clip-on" that is positioned in front of a daytime scope, a sighting device including night vision binoculars associated with a clear sight attached to the weapon.

[0007] These known solutions each have advantages and disadvantages, but none fully meets the overall need identified above.

[0008] The clear viewfinder solution is particularly appreciated because it offers good precision, while preserving a good perception of the overall situation, the clear viewfinder transmitting the landscape without magnification.

[0009] Aiming with a laser sight, widely used especially at night, is very advantageous because it allows for rapid firing in dynamic combat, without needing to align the eye behind a sight or even shoulder the weapon in extreme situations. However, laser sights remain inconspicuous, particularly at night. Even when emitting in the near-infrared spectrum, they are easily detectable with night-vision goggles or even with certain equipment using a near-infrared camera.

[0010] Shooting glasses in general, whether day or night vision goggles, image intensifier or thermal infrared, feature Their advantage lies in their precision, thanks in particular to their magnification. However, they have the disadvantage of requiring the aiming eye to be positioned close to an eyepiece; furthermore, the user cannot use the other eye for overall perception. This operation takes time, resulting in a loss of effectiveness in dynamic combat. In addition, the shooter is momentarily disconnected from their surroundings and may therefore miss new threats. Finally, at night, if equipped with night-vision binoculars, the combatant must remove them to properly position a free eye behind the scope. Again, this represents an additional delay in the action and a disconnect from the combatant's environment.

[0011] Infrared or thermal shooting glasses have the same disadvantages but offer some significant advantages: night vision, including in total darkness, improved vision in the mists and smoke of the battlefield and above all the ability to "uncamouflage" any hot target.

[0012] To attempt to provide a suitable solution, it is possible to combine several systems in a single piece of equipment. For example, as shown in Figure 1, some aiming equipment combines an IL or IR riflescope with a clear sight. In this case, the scope includes a thermal camera and a viewing device. The thermal camera has a focusing lens 1 and a photosensitive receptor 2. The viewing device has a micro-display 3 and an eyepiece 4. The clear sight has an illuminated symbol 5, collimation optics 6, and a superposition optic (typically a beam splitter) for direct vision 7.

[0013] These solutions result in relatively bulky equipment that offers a juxtaposition of functions without truly combining them. At any given moment, the user must choose between using the clear sight or the scope, and therefore never benefits from the combined advantages of both systems. In the case of a system combining a thermal infrared scope and a clear sight, the user must choose between the rapid target acquisition and situational awareness offered by the clear sight, or the camouflage detection and night vision provided by the thermal scope.

[0014] An improved solution is illustrated in Figure 2. The same references as those in Figure 1 designate the same elements as those described in Figure 1. The architecture of Figure 2 consists of combining an "advanced" reflex viewfinder architecture with a single display 3 which handles everything: video feed, symbology, reticle, etc. The image from the display is projected to infinity using an eyepiece 3. Fusion with the scene is achieved using a semi-reflective plate 7.

[0015] The reflex sight with display of figure 2, coupled with a light-intensifying or infrared camera 2, thus presents a real added value because it provides additional assistance for highlighting a target in difficult conditions (target camouflage, darkness, ...) by compactly combining a "night" and "day" vision.

[0016] The solution in Figure 2, while a significant improvement over the architecture in Figure 1, has a drawback. If display 3 malfunctions, all video, symbology, and reticle functions of the viewfinder are lost. Furthermore, the display must have a high refresh rate to perform all the aforementioned functions (typically 20 Hz or more). This results in significant power consumption, limiting the battery life of the viewfinder in Figure 2 to just a few hours. Once the batteries are depleted, this reflex viewfinder ceases to function, even for basic functions such as displaying a reticle.

[0017] In summary, existing solutions based on a single principle such as a clear sight, pointer or scope do not meet all the needs of the infantryman for shooting in all situations.

[0018] The invention aims to overcome some of the aforementioned problems of the prior art. To this end, an object of the invention is a sighting or observation telescope comprising, in particular, a camera, a first video micro-display showing an image of the outside landscape acquired by the camera, and a second video micro-display. The use of two displays makes the sight of the invention more versatile and robust. Furthermore, by selecting a micro-display with lower power consumption compared to the other micro- The sight of the invention allows operation in a "degraded" mode via the display of a customizable red dot / reticle with a battery life of several hundred hours. This allows the user to extend their mission or when the battery powering the sight's capacity drops below a critical threshold. Summary of the invention:

[0019] To this end, an object of the invention is a sighting or observation telescope having a sighting or observation axis x and comprising, in a mechanical structure: - a camera, - a first micro-video display showing an image of the outside landscape acquired by the camera, called the first object - an eyepiece connected to the first video micro-display and forming a first image of the first object at infinity - a second micro-video display showing a second object - an optical combining device arranged optically downstream of the eyepiece and is adapted to form an image at infinity of the second object, called the second image, and to superimpose the first and second images on the outside landscape.

[0020] According to one embodiment, the second micro-display is a low power consumption micro-display compared to the first micro-display.

[0021] Preferably, in this embodiment, the second microdisplay has a refresh rate less than or equal to 2 Hz, the first microdisplay has a refresh rate greater than or equal to 20 Hz.

[0022] Preferably, in this embodiment, the scope includes a battery powering the camera, the first and second video micro-displays, and a processor, said processor being configured to operate the battery in two distinct modes consisting of: - in a first mode, power the first video micro-display and not power the second video micro-display, or power both the first and second micro-displays when the battery capacity exceeds a predetermined limit or when the user chooses, for example by pressing a remote control on said mechanical structure, - in a second mode, power the second micro-video display and not power the first micro-video display when a battery capacity is less than the predetermined limit, or when the processor detects a malfunction of the first display, or when the user chooses it, for example by pressing a remote control element on said mechanical structure.

[0023] As a further preference, the predetermined limit corresponds to a battery life in the first operating mode of less than 1 hour of use.

[0024] According to one embodiment, the first micro-display emits radiation in a first spectral range and the second micro-display emits radiation in a second spectral range, disjoint from the first spectral range, or the first and second micro-displays emit radiation in the same spectral range but with cross polarization.

[0025] According to one embodiment, the optical combination device comprises: - a flat, semi-reflective surface inclined at approximately 45 degrees to the line of sight or observation axis x, or a surface comprising a dichroic coating adapted to reflect a spectral range of the radiation emitted by the first micro-display, said flat, semi-reflective surface being adapted to perform said superimposition of the first and second images onto the external landscape - a holographic or diffractive element or a metasurface arranged on the optical path of the rays from the second display and adapted to form said second image.

[0026] Preferably, the holographic or diffractive element or said metasurface has a holographic treatment and / or a structure specifically adapted to form a ray image having a wavelength in the second spectral range and adapted to transmit the first spectral range.

[0027] Preferably, the holographic or diffractive element or the metasurface is deposited or applied to the flat semi-reflective surface. Alternatively, the holographic or diffractive element or the metasurface is separated from the flat semi-reflective surface.

[0028] According to one embodiment, the optical combination device comprises: - a flat, semi-reflective surface inclined at approximately 45 degrees to the line of sight or observation axis x, said flat, semi-reflective surface being adapted to perform said superimposition of the first and second images onto the external landscape - a concave surface of the "freeform" or aspherical type inclined on the x-axis of sighting or observation and arranged on the optical path of the rays coming from the second display so as to form said second image.

[0029] According to one embodiment, the optical combination device comprises: - a flat, semi-reflective surface inclined at approximately 45 degrees to the line of sight or observation axis x, said flat, semi-reflective surface being adapted to perform said superimposition of the first and second images onto the external landscape - an additional eyepiece adapted to form the second image, - a pupil-expanding light guide arranged on the optical path of the rays from the second display and adapted to expand a pupil of the additional eyepiece in two directions of space, also participating in said superimposition of the first and second image on the outside landscape. Brief some

[0030] Other features, details and advantages of the invention will become apparent from the description provided with reference to the accompanying drawings given by way of example, which represent, respectively:

[0031] [Fig. 1] A schematic view of a telescope from the prior art,

[0032] [Fig. 2] A schematic view of a prior art telescope,

[0033] [Fig. 3A] a perspective view of a sighting or observation telescope according to the invention,

[0034] Fig. 3B] a schematic view of a sighting or observation telescope according to the invention,

[0035] Fig.3C] a perspective view of a sighting or observation telescope according to a preferred embodiment of embodiment M1 of the invention,

[0036] [Fig. 4] a schematic representation of one embodiment of the telescope of the invention,

[0037] [Fig. 5] a schematic representation of one embodiment of the telescope of the invention,

[0038] [Fig. 6] a schematic representation of one embodiment of the telescope of the invention,

[0039] In the figures, unless otherwise indicated, the elements are not to scale and identical references refer to identical elements. Detailed description:

[0040] Figure 3A shows a perspective view of a sighting or observation telescope 10 according to the invention. Figure 3B is a schematic representation of the elements included in the mechanical structure SM of the sighting or observation telescope 1 according to the invention, having a sighting or observation axis x. The telescope 10 essentially comprises two main sub-assemblies: a camera Cl and a viewing device DV, the structure of which is detailed more precisely in Figure 3B.

[0041] The DV viewing device comprises a first and second microdisplay MA1, MA2, an eyepiece OC associated with the first display MA1, and a combining optical device SC. For example, as illustrated in the In Figure 3A, the SC combination optical device is mounted above the camera Cl. Alternatively, the camera is above or to the side of the SC combination optical device. All optical and electronic components are integrated into the sealed SM mechanical structure, which protects them from the external environment and impacts.

[0042] This SM structure features a mechanical IF mounting interface allowing it to be attached to a weapon equipped with a standard interface. This interface is, for example, a Picatinny rail or its equivalent.

[0043] The structure also includes an IC assembly of buttons and control elements enabling, in particular, the On / Off control of the various equipment functions, the brightness adjustment of the MA1 and MA2 video microdisplays, the electronic and mechanical adjustment of the screen layout, and the electronic adjustment of the overlay of the different images generated on the external landscape. It can be located on one of the two lateral sides of the telescope. As a non-limiting example, in Figure 3A, the assembly includes three buttons located on the left lateral side of the telescope, with additional buttons located on the right side.

[0044] According to one embodiment of the invention, the camera Cl is a thermal camera, comprising an infrared lens Ol operating in the spectral band located between 8pm and 12pm and an infrared sensor CPT sensitive in the same spectral band or between 3 and 5 / zm..

[0045] Alternatively, according to another embodiment, the camera is a low-light camera implementing a low-noise CPT “CMOS” sensor, “CMOS” being the acronym for “Complementary Metal Oxide Semiconductor”, or an “EB-CMOS” sensor, an acronym for “Electro-Bombarded CMOS”, or any other digital low-light camera.

[0046] The camera can also be a "SWIR" camera, an acronym for "Short Wave InfraRed" operating in the spectral band between 1 pm and 2 pm, capturing night light from night luminescence or "night glow" and also offering camouflage capabilities.

[0047] The Cl camera includes power supply, sensor control and image processing electronics as well as a power supply unit (not shown) receiving several batteries or a rechargeable battery pack to ensure its autonomy, which is for example located at the rear of the telescope, on the observer's eye side.

[0048] The DV viewing device includes the first video micro-display MA1, the OC eyepiece forming an image of the first video micro-display at infinity, and the electronics necessary for powering and controlling the first micro-display.

[0049] The first microdisplay MA1 shows a video aiming reticle, possibly enhanced with elevation correction elements, symbols, or stadia graduations. It also displays an image of the surrounding landscape acquired by the camera, referred to as the first object. R1 denotes the radiation emitted by the first microdisplay MA1. In one embodiment, the first microdisplay MA1 displays only the image of the surrounding landscape acquired by the camera.

[0050] The DV display system further includes the second video microdisplay MA2 and the optical combination device SC. The image displayed by the second video microdisplay MA2 is called the "second object," and R2 denotes the radiation emitted by the second video microdisplay MA2.

[0051] The SC combining optical device is optically arranged downstream of the OC eyepiece and is adapted to form an image at infinity of the second object, called the second image, and to superimpose the first and second images onto the outside landscape. Various examples of SC combining optical devices are described later (see Figures 4 to 6).

[0052] The first and second micro-video displays MA1, MA2, are examples of "OLED" displays, an acronym meaning "Organic Light Emmitting Diode", "LCD" displays, an acronym meaning "Liquid Crystal Display", or "LCOS" displays, an acronym meaning "Liquid Crystal On Silicon".

[0053] The use of two displays makes the telescope of the invention more versatile by combining several functions (for example, one display relaying an IR image in a spectral band between 1 and 2 pm and another relaying a thermal image (in a spectral band between 2 and 15 pm). In addition, this makes the telescope of the invention more robust, for example by allowing switching to the second micro-display in the event of a malfunction of the first micro-display.

[0054] Furthermore, by selecting a low-power microdisplay compared to the other microdisplay, the scope of the invention allows operation in a "degraded" mode via the display of a customizable red dot / reticle with a battery life of several hundred hours. Thus, the user can extend their mission or when the battery powering the sight's capacity drops below a critical threshold.

[0055] More specifically, according to a first embodiment M1, the second micro-display is a low-power micro-display compared to the first micro-display. By "low power consumption," we mean here that the second micro-display has a power consumption between 0.5 mW and 10 mW, while the first micro-display has a power consumption greater than or equal to 50 mW.

[0056] Preferably, in embodiment M1, the second microdisplay displays a red dot or a luminous symbol. Since the luminous object remains fixed over time, the power consumption of the second microdisplay is significantly reduced.

[0057] Preferably, in embodiment M1, the second microdisplay has a refresh rate of 2 Hz or less to reduce its power consumption. Furthermore, the refresh rate of the first microdisplay is high to be compatible with a video stream. Therefore, the first microdisplay has a refresh rate of 20 Hz or more.

[0058] As a non-limiting example, in embodiment M1, the first video micro-display MA1 is a Microoled MDP07 OLED. It allows the reflex viewfinder to function nominally by projecting all available information: reticle, symbology, image, video stream...

[0059] As a non-limiting example, in embodiment M1, the second video micro-display MA2 is an OLED MDP05 from Microoled.

[0060] According to a variant (noted V1) of the first embodiment, the first micro-display MA1 only displays the image of the outside landscape acquired by the camera, while the second micro-display MA2 displays a sighting reticle.

[0061] Figure 3C illustrates a preferred embodiment of embodiment M1, in which the scope 10 includes a BT battery powering the camera Cl, the first and second video microdisplays MA1, MA2 and a UT processor controlling the battery operation according to a first and second mode.

[0062] In the first mode, the battery powers the first video microdisplay and does not power the second video microdisplay when the battery capacity exceeds a predetermined limit. Alternatively, according to variant V1, the battery powers both microdisplays MA1 and MA2 in the first operating mode.

[0063] In the second mode, the battery powers the second video microdisplay and does not power the first video microdisplay when the battery capacity falls below a predetermined limit. Thus, the UT processor allows the battery to operate in a second "degraded" mode to conserve the scope's battery life when the battery capacity drops below a limit defined by the user or manufacturer. In this degraded mode, only a simple reticle is available to the user. Alternatively, the reticle is displayed in combination with at least one element displaying information about the sight, such as a low battery indicator and / or elements allowing various adjustments like electronic reticle setting, brightness adjustment, etc.

[0064] Ideally, the predetermined battery limit corresponds to a battery life of less than one hour in the first operating mode. As a non-limiting example, this limit is 1000 mAh at ±50%. This limit allows for continued display of a red dot with a battery life of several hundred hours by switching to the second battery operating mode.

[0065] In a first variant of the embodiment shown in Figure 3C, the processor is further configured so that the battery operates in the second mode (powering the second video microdisplay and not the first video microdisplay) when the processor detects a malfunction of the first display or the camera Cl. For example, the malfunction could be a power supply problem. This variant results in a more robust telescope 10.

[0066] In a second variant of the embodiment shown in Figure 3C, which can be combined with the first variant, the processor is further configured so that the battery operates in either the second or first mode, depending on the user's selection, for example, by pressing one of the remote IC control elements on the SM mechanical structure. This variant allows for a more versatile telescope by selecting an enhanced (first mode) or degraded (second mode) mode depending on the mission and its evolution.

[0067] According to the embodiment illustrated in Figures 3B and 3C, the telescope of the invention is a reflex viewfinder, and the optical system consisting of the camera, the first micro-display, and the eyepiece has a unity magnification, the image of the first micro-display conforming to that of the external landscape. The SC optical combining device then ensures the perfect superimposition of the micro-display image onto the landscape.

[0068] Alternatively, according to another embodiment, the telescope has a magnification greater than one. For this purpose, the telescope 1 includes, for example, an afocal optical system arranged optically downstream of the SC combining optical device to form a superimposed image of the first and second micro-displays and the observed scene with a magnification greater than 1.

[0069] As explained previously, the SC combination optical device is an optical element performing a collimation function for the beam from the second micro-display and a superposition function by superimposing the image from the first micro-display and the image from the second micro-display onto the outside landscape.

[0070] To facilitate the design and fabrication of the SC combination optical device, the first microdisplay emits R1 radiation in a first spectral range, and the second microdisplay emits R2 radiation in a second spectral range, separate from the first. This also ensures optimal transmission of the light from the observed scene and the light from the first microdisplay.

[0071] In order to further simplify the design of the SC device, advantageously, the first and second spectral ranges have a spectral span of less than or equal to 20 nm, for example by adding spectral filters arranged in front of the micro-displays.

[0072] Alternatively, to facilitate the design and manufacture of the SC combination optical device, the two microdisplays emit radiation R1, R2 respectively in the same spectral range but with cross polarization.

[0073] Figure 4 is a schematic representation of an embodiment of the telescope 10 in which the SC combination optical device is a holographic or diffractive EH element, or a metasurface.

[0074] The SC optical combination device comprises a flat semi-reflective surface SR or a surface SR with a dichroic coating adapted to reflect the spectral range of R1 radiation, inclined at approximately 45 degrees to the line of sight or observation axis x. "Approximately 45 degrees" means 45 degrees ±5 degrees. The flat semi-reflective surface (or the surface with a dichroic coating) SR is adapted to superimpose the image of the first microdisplay (the first image) and the image of the second microdisplay (the second image) onto the external landscape.

[0075] Typically, the semi-reflective surface is integrated into a beam splitter with two flat, parallel faces. Alternatively, the semi-reflective surface is integrated into a beam splitter cube with two flat, parallel faces, or even a prism.

[0076] The holographic or diffractive element, or EH metasurface, is arranged along the optical path of the R2 rays originating from the second display. By its structure, the holographic or diffractive element or the EH metasurface is adapted to form the image at infinity of the second micro-display.

[0077] Holographic optical elements are optical components obtained by recording a two-wave interference phenomenon in a photosensitive material. The interference causes variations in the refractive index within the material, which are preserved when the hologram is subsequently developed. These elements are called thick-phase holograms because the photosensitive material must have a certain thickness to allow the recording of a significant number of interference fringes, and also because the refractive index variations result only in phase changes in the incident light waves without any change in amplitude. These elements can operate by reflection or transmission. These holographic elements exhibit a number of remarkable properties. Indeed, it is possible to obtain a wide variety of optical functions by varying the shape of the recording waves.These functions are, in part, independent of the shape of the support for the holographic optical element. Thus, a holographic optical element recorded on a flat support can possess optical power and have a function comparable to that of a prism, a lens, or a mirror.

[0078] In the embodiment of Figure 4, in the case where the element EH is a holographic component, the holographic treatment is thus adapted to present optical power in order to be able to perform the collimation function of the R2 rays coming from the second display.

[0079] Finally, these holographic elements exhibit, by nature, spectral selectivity. For a given incidence, the holographic component reflects light in a given spectral band and is transparent outside this spectral band, the spectral band depending on the recording wavelength and more generally, on the recording conditions (see in particular the article "Coupled Wave Theory for thick Hologram Gratings", The Bell System Technical Journal, Vol. 48, Nov. 1969, No. 9 for all information on the diffractive operation of this type of hologram).

[0080] Therefore, when the EH element is a holographic component in the embodiment of Figure 4, the first microdisplay emits radiation in a first spectral range, and the second microdisplay emits radiation in a second spectral range distinct from the first spectral range, both having a spectral span less than or equal to 20 nm. Thus, the holographic element EH has a holographic coating and / or a structure specifically adapted to form an image at infinity of rays with a wavelength in the second spectral range and adapted to transmit the first spectral range.

[0081] In the embodiment where the EH element is a diffractive component or a metasurface, this spectral selectivity can also come from an angle of incidence of the rays coming from the first display with respect to the EHD element.

[0082] Alternatively, in another embodiment, to perform the superposition appropriately when the EH element is a diffractive component or a metasurface, the two microdisplays MA1, MA2 emit radiation R1, R2 in the same spectral range but with cross-polarization. In this embodiment, one or more polarized screens are arranged along the optical path of the radiation R1 such that the EH element forms an image at infinity of the rays exhibiting the polarization associated with the microdisplay MA2, and transmits the rays exhibiting the polarization associated with the microdisplay MA1.

[0083] According to the embodiment illustrated in Figure 4, the holographic or diffractive element or the metasurface EH is arranged so as to be separated from the flat semi-reflective surface SR. This embodiment facilitates the design and manufacture of the EH and SR elements. Indeed, it is then possible to design an EH element so that it has sufficient optical power for the R2 rays to perform the collimation function, without also performing a superposition function for the first and second images on the external landscape. Preferably, in this embodiment, the holographic or diffractive element or the metasurface EH is arranged so as to be substantially perpendicular to the line of sight or observation axis x. This maximizes the compactness of the telescope. the invention. Furthermore, depending on the structure of the EH element, this potentially maximizes the transmission of RE rays from the outside landscape. By "substantially perpendicular," we mean here that the EH element is perpendicular to ±10° from the line of sight or observation axis x.

[0084] By way of non-limiting example, in the embodiment where the EH element is a metasurface or a diffractive element, the EH element is machined for example by a diamond point, by laser ablation, by lithography, by engraving, by molding, or by pressing.

[0085] In the embodiment where the EH element is a diffractive element, the latter may comprise two or more relief levels (also called levels).

[0086] In the embodiment where the EH element is a metasurface, the latter is created by modulating the density of the reliefs which are all approximately the same height relative to a planar substrate.

[0087] By way of non-limiting example, in the embodiment where the EH element is a holographic element, the latter may be a thick volumetric hologram obtained by the interference of two coherent light beams producing a variation in the refractive index in a layer of photosensitive material. Alternatively, the EH element may be a thin volumetric hologram in which the variation in index is perpendicular to the substrate, or a surface hologram, or a CGH (computer-generated hologram) produced by the same process as a diffractive EH element of the invention.

[0088] Alternatively, according to an embodiment different from that illustrated in Figure 4, the holographic or diffractive element or the metasurface EH is deposited or attached to the flat semi-reflective surface SR. This embodiment offers greater compactness than that of Figure 4. However, it has the disadvantage of being more complex to design and manufacture because a single element must perform a collimation function for the R2 rays and a superposition function for the first and second images onto the external landscape. By way of non-limiting example, in this embodiment, the EH element allows the collimation of the R1 radiation emitted by the microdisplay MA1 and the collimation of the R2 radiation emitted by the microdisplay. MA2. The separation of the collimation functions of radiation R1 and collimation of R2 is made possible via two distinct variants: the two microdisplays MA1, MA2 emit radiation in the same spectral range but with cross-polarization, - the first micro-display emits the R1 radiation in a first spectral range and the second micro-display emits the R2 radiation in a second spectral range, disjoint from the first spectral range.

[0089] Figure 5 is a schematic representation of an embodiment of the telescope 10 in which the combination optical device SC comprises the flat semi-reflective surface SR, an additional eyepiece OC' and a pupil-expanding light guide PE.

[0090] The flat semi-reflective surface SR of the embodiment of Figure 5 is identical to that described in the embodiment of Figure 4.

[0091] The additional eyepiece OC' is arranged to form an image of the second micro-display at infinity.

[0092] The PE pupil-expanding light guide is arranged on the optical path of the rays from the second display and is adapted to expand a pupil of the additional eyepiece OC' in two directions of space, also participating in the superimposition of the first and second images on the outside landscape.

[0093] A pupil-expanding light guide (PE) is a known component, made of a transparent material and comprising flat, parallel faces. Light beams from the second microdisplay MA2, collimated by the additional eyepiece OC', enter the light guide through one of its lateral faces. Entry into the guide can be achieved using a prism, but also with a grating, which is then called an input grating. These beams propagate through the light guide by total internal reflection off flat, parallel faces. For the observer to perceive an image, it is necessary to project it out of the guide. Several optical solutions exist. As a first example, the PE light guide comprises two parallel semi-reflecting plates arranged at an angle between the parallel faces of the PE light guide, so as to extract a portion of the light. collimated beams. As a second example, the PE light guide includes a network of microstructures or microprisms, or a diffraction grating, which performs the same functions. These elements can be located on one of the two faces of the light guide. They can also be located inside the guide.

[0094] In the embodiment illustrated in Figure 5, the observer Y looks at the landscape directly through the PE light guide. This is referred to as a "see-through" PE light guide.

[0095] The integration of the PE pupil-expanding light guide significantly reduces the scope's x-axis dimensions. Compared to a beam splitter inclined at 45° to the x-axis, the PE light guide extends primarily along a plane roughly perpendicular to the x-axis. This minimizes its length (x-axis dimension), allowing the user to have a better understanding of their surroundings.

[0096] Preferably, according to an embodiment different from that illustrated in Figure 5, the flat semi-reflective surface SR is replaced by an additional pupil-expanding light guide adapted to expand the pupil of the first eyepiece in two spatial directions, superimposing the first and second images onto the external landscape. This embodiment offers even greater compactness compared to the embodiment in Figure 5.

[0097] Figure 6 is a schematic representation of an embodiment of the telescope 10 in which the SC optical combination device comprises the flat semi-reflective surface SR (or the SR surface with a dichroic coating) and an SFF plate comprising two concave freeform or aspherical surfaces. A freeform surface is defined as a surface that lacks rotational symmetry. It is the shape of these surfaces that directly generates the optical power to reflect the image from the second microdisplay at infinity to the user's eye. It is necessary to use an SFF plate with two freeform surfaces or aspherical so as not to disturb the view of the outside landscape through this SFF blade.

[0098] The flat semi-reflective surface SR (or the surface SR including a dichroic treatment) of the embodiment of Figure 6 is identical to that described in the embodiment of Figures 4 and 5.

[0099] The concave SFF surface, of the "freeform" or aspherical type, is inclined around the x-axis of the viewing or observation line and is positioned along the optical path of the rays from the second display so as to form the image at infinity of the second microdisplay MA2. Compared to the previously mentioned embodiments, the concave SFF surface offers more degrees of freedom for optimizing the surface profile, thus enabling better collimation.

[0100] In all its embodiments, the riflescope according to the invention can include complementary modular optical systems that modify the perception of the external landscape. For example, an afocal magnifying lens with a magnification of 3x can be placed downstream of the optical combiner. Similarly, an optical module with a light intensifier, invariant in magnification and axial deviation, can be placed upstream of the SC optical combiner. The user thus perceives both an intensified image and a thermal image of the external landscape.

Claims

Claims 1. Sighting or observation telescope (10) having a sighting or observation axis x and comprising, in a mechanical structure (SM): - a camera (Cl), - a first video micro-display (MA1) displaying an image of the exterior landscape acquired by the camera, called the first object - an eyepiece (OC) associated with the first video micro-display and forming a first image of the first object at infinity - a second video micro-display (MA2) displaying a second object - an optical combining device (SC) optically arranged downstream of the eyepiece and is adapted to form an image at infinity of the second object, called the second image, and to superimpose the first and second images on the external landscape.

2. Glasses according to claim 1, in which the second micro-display is a micro-display with low power consumption compared to the first micro-display.

3. Glasses according to claim 2, in which the second micro-display has a refresh rate less than or equal to 2 Hz, the first micro-display having a refresh rate greater than or equal to 20 Hz.

4. Glasses according to claim 2 or 3, comprising a battery powering the camera, the first and second video micro-displays and a processor, said processor being configured to operate the battery in two distinct modes consisting of: - in a first mode, powering the first video micro-display and not powering the second video micro-display or powering the first and second micro-displays (MA1, MA2) when a battery capacity is greater than a predetermined limit or when the user chooses it, for example by pressing a control member (IC) remote from said mechanical structure, - in a second mode, powering the second video micro-display and not powering the first video micro-display when a battery capacity is lower than the predetermined limit, or when the processor detects a malfunction of the first display, or when the user chooses it, for example by pressing a control member (IC) remote from said mechanical structure.

5. Glasses according to the preceding claim, in which the predetermined limit corresponds to a battery life in the first operating mode of less than 1 hour of use.

6. Glasses according to any one of the preceding claims, in which the first micro-display emits radiation in a first spectral range and the second micro-display emits radiation in a second spectral range, separate from the first spectral range or the first and second micro-displays (MA1, MA2) emit radiation in the same spectral range but having cross-polarization.

7. Glasses according to any one of the preceding claims, in which the optical combination device comprises: - a planar semi-reflecting surface (SR) inclined at approximately 45 degrees relative to the sighting or observation axis x or a surface (SR) comprising a dichroic treatment adapted to reflect a spectral range of the radiation emitted by the first micro-display, said planar semi-reflecting surface (SR) being adapted to carry out said superposition of the first and second images on the external landscape - a holographic or diffractive element or a metasurface (EH) arranged on the optical path of the rays coming from the second display and adapted to form said second image.

8. Glasses according to the preceding claim in combination with claim 6, wherein said holographic or diffractive element or said metasurface (EH) has a holographic treatment and / or structure specifically adapted to form an image of rays having a wavelength included in the second spectral range and adapted to transmit the first spectral range.

9. Glasses according to claim 7 or 8, in which said holographic or diffractive element or said metasurface (EH) is deposited or attached to the flat semi-reflecting surface (SR).

10. Glasses according to claim 7 or 8, wherein said holographic or diffractive element or said metasurface (EHD) is separated from the planar semi-reflective surface (SR).

11. Scope according to the preceding claim, in which said holographic or diffractive element or said metasurface (EH) is arranged so as to be substantially perpendicular to the axis of sight or observation x.

12. A telescope according to claim 10, wherein said holographic or diffractive element or said metasurface (EH) comprises a concave surface inclined on the sighting or observation axis x.

13. Glasses according to any one of claims 1 to 6 and 8 to 12, in which the optical combination device comprises: - a planar semi-reflecting surface (SR) inclined at approximately 45 degrees relative to the sighting or observation axis x, said planar semi-reflecting surface (SR) being adapted to carry out said superposition of the first and second images on the external landscape - a concave surface (SFF) of the “freeform” or aspherical type inclined on the axis of sight or observation x and arranged on the optical path of the rays coming from the second display so as to form said second image.

14. Glasses according to any one of claims 1 to 6 and 8 to 12, in which the optical combination device comprises: - a flat semi-reflecting surface (SR) inclined at approximately 45 degrees relative to the sighting or observation axis x, said flat semi-reflecting surface (SR) being adapted to carry out said superposition of the first and second images on the external landscape - an additional eyepiece (OC') adapted to form the second image, - a pupil expansion light guide (PE) arranged on the optical path of the rays coming from the second display and adapted to extend a pupil of the additional eyepiece (OC') in two directions of space while also participating in said superposition of the first and second images on the external landscape.

Images