OBSERVATION SYSTEM AND METHOD, AND MANUFACTURING METHOD OF SUCH A SYSTEM

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the observation of a scene, and more particularly to observation using a portable system. STATE OF THE ART

[0002] Currently, monocular systems, or binoculars, exist for observing scenes. Some of these systems can be equipped with a laser pointer, that is, a device to illuminate a scene with a laser point at a wavelength in the visible spectrum or at a wavelength in the near-infrared range so that it is easily detectable by night-vision binoculars.

[0003] Other systems may be equipped with a rangefinder using infrared radiation to measure the distance between the scene to be observed and the system.

[0004] For example, US patent 10451716 B2 discloses a distance measurement system using laser remote sensing, or LIDAR (laser detection and ranging). Another example is US patent application US2020 / 386869, which discloses a fiber optic laser distance detector and estimator.

[0005] One example is European patent EP2637038 B1, which discloses a distance measurement system using laser-type optical radiation.

[0006] We can also mention international application WO200663740 A1, which discloses a pulsed electromagnetic radiation distance measurement system of the laser type in the visible range.

[0007] But these systems are bulky and poorly suited when, for example, the user wants to use an observation system with a device equipped with an illuminator while moving easily.

[0008] We can also cite US patent application US2018 / 180734, which discloses an observation device comprising two observation channels and two laser emission / reception channels, for targeting a target to determine the distance along an axis. However, such a device is not sufficiently robust because the observation and laser emission / reception channels may become misaligned, particularly during shocks or vibrations.

[0009] We can also mention US patent application 2020386869, which discloses a fiber optic laser detector and distance estimator, and US patent application 2018 / 180734, which discloses an observation device comprising two observation channels and two laser emission / reception channels. SUMMARY OF THE INVENTION

[0010] One objective is to overcome these drawbacks, and more specifically to provide compact means of observation.

[0011] Another objective is to provide lightweight, portable observation equipment.

[0012] Another objective is to provide observation methods with reduced energy consumption.

[0013] According to one aspect, an observation system is proposed, comprising: a main optical channel capable of receiving a first optical radiation emitted by a scene to be observed and comprising a main sensor configured to develop a digital image from the first optical radiation; and an emitter configured to emit a second optical radiation in the infrared domain.

[0014] The main optical path includes an optical element configured to transmit part of the first optical radiation to the main sensor and to transmit the second optical radiation to the scene to be observed.

[0015] Thus, a compact observation system is provided that illuminates a scene to be observed. The emitter may include an amplifier configured to emit a second optical beam of the laser type.

[0016] The second optical radiation can be of the pulsed type, the system further comprising a receiver configured to receive a portion of the second pulsed optical radiation returned by the scene to be observed and an electronic control unit configured to determine a distance from the scene to be observed from the portion of the second pulsed optical radiation returned.

[0017] Thus, a compact observation system is provided which allows both the scene to be illuminated and the distance between the scene and the observation system to be measured.

[0018] The system may include an optical connector configured to transmit the second optical radiation and an optical fiber connecting the optical connector to the transmitter.

[0019] Optical fiber can include a first part connecting the optical connector to the transmitter, and a second part connecting the optical connector to the receiver.

[0020] The system may further include a second optical path comprising an eyepiece and configured to transmit another part of the first optical radiation transmitted by the optical element to the eyepiece.

[0021] Thus, the second optical path allows direct observation of the scene adapted for daytime vision in the absence of a battery, and helps to limit the consumption of the sensors.

[0022] The system may also include an optical assembly comprising the optical element, and in which the main sensor and optical connector are fixedly mounted on the optical assembly.

[0023] The optical assembly may include an optical system configured to transmit the other part of the first optical radiation to the eyepiece, the optical assembly forming a single unit.

[0024] This single-piece design makes the system particularly compact and space-saving. Advantageously, the optical assembly includes a sighting reticle.

[0025] According to another aspect, an observation method is proposed, comprising: a reception of a first optical radiation emitted by a scene to be observed from a main optical channel equipped with a main sensor developing a digital image from the first optical radiation; and an emission of a second optical radiation in the infrared domain.

[0026] The method involves transmitting part of the first optical beam to the main sensor and transmitting the second optical beam from the main optical path to the scene to be observed.

[0027] The second optical radiation can be of the pulsed type, and the method includes receiving a portion of the second pulsed optical radiation reflected back by the scene to be observed and determining a distance from the scene to be observed from the portion of the second pulsed optical radiation reflected back.

[0028] According to another aspect, a method for manufacturing an observation system is proposed, comprising the provision of a main optical channel capable of receiving a first optical radiation emitted by a scene to be observed and comprising a main sensor configured to develop a digital image from the first optical radiation, and the provision of an emitter configured to emit a second optical radiation in the infrared domain.

[0029] The method includes mounting, in the main optical path, an optical element transmitting a portion of the first optical radiation to the main sensor and transmitting the second optical radiation to the scene to be observed.

[0030] The method may include mounting the optical element within an optical assembly, and mounting the main sensor on the optical assembly.

[0031] The method may also include mounting an optical fiber on an optical connector to transmit the second optical radiation and to receive the portion of the pulsed optical radiation returned, and mounting the optical connector on the optical assembly.

[0032] The optical connector may include an optical prism and a ferrule connecting the optical fiber to the prism, and the optical connector assembly step may involve adjusting the position of the optical connector along an axis parallel to a longitudinal axis of the ferrule. The optical connector assembly step may also involve adjusting the position of the optical connector along an axis perpendicular to the longitudinal axis of the ferrule.

[0033] The process may also include, prior to the optical connector mounting step, mounting a sighting reticle on the optical assembly.

[0034] Advantageously, the process includes, after at least one of the adjustment steps, fixing the optical connector onto the optical assembly. BRIEF DESCRIPTION OF THE FIGURE

[0035] Other advantages and features will become clearer from the following description of particular embodiments and implementations of the invention, given by way of non-limiting examples and shown in the accompanying drawing, in which the figure 1 schematically illustrates one embodiment of an observation system according to the invention.

[0036] The drawing is given by way of example and is not limiting of the invention. It constitutes a schematic representation of principle intended to facilitate understanding of the invention and is not necessarily to scale with practical applications. DETAILED DESCRIPTION

[0037] On the figure 1A scene observation system 1 is shown. Generally, system 1 comprises a main optical channel 2 and a transmitter 100. Advantageously, observation system 1 is portable, meaning it can be carried by hand by a user. Furthermore, the main optical channel 2, also called the first optical channel, is capable of receiving a first optical beam 60 emitted by a scene to be observed, which is not shown in the diagram. figure 1 For the sake of simplicity, optical radiation is defined as electromagnetic radiation encompassing the ultraviolet, visible, and infrared ranges. The scene to be observed may be located outdoors or indoors. The main optical channel 2 includes a primary sensor 7 configured to construct a digital image from the first optical radiation 60. The primary sensor 7 is an electronic device powered by a battery, not shown in the diagram. figure 1For the sake of simplicity, the emitter 100 is configured to emit a second optical beam 101 in the infrared range. Preferably, the second optical beam 101 has a wavelength in the near-infrared range. Even more preferably, the second optical beam has a wavelength greater than or equal to 700 nanometers. For example, the wavelength of the second optical beam 101 can be between 700 and 2000 nanometers. In general, the emitter 100 illuminates the scene to be observed by emitting the second optical beam 101. In particular, the main optical channel 2 includes an optical element 11 configured to transmit a portion 22 of the first optical beam 60 to the main sensor 7 and to transmit the second optical beam 101 to the scene to be observed. In other words, the emission of the second optical beam 100 is carried out from the main optical channel 2.An optical element is defined as an element that modifies the path of optical radiation or the properties of optical radiation, such as a mirror, a lens, a diffraction grating, a prism, etc. The main optical path 2 may further include an optical device 6, such as a lens, configured to transmit the first optical radiation 60 to the main sensor 7. In this case, the optical element 11 is configured to transmit the second optical radiation 101 to the optical device 6, and the optical device 6 is configured to transmit the second optical radiation 101 to the scene to be observed. In particular, the optical device 6 is transparent to optical radiation.

[0038] The emitter 100 may include an amplifier 103 configured to emit the second optical beam 101 of the laser type. This provides illumination of the scene with a laser point that can be observed by an infrared-sensitive observation system.

[0039] Furthermore, the emitter 100 is configured to emit a second pulsed optical beam 101 with a wavelength in the infrared range. The system 1 also includes a receiver 104 configured to receive a portion 105 of the second pulsed optical beam 101 reflected by the scene to be observed. The system also includes an electronic control unit 106, for example a microprocessor, configured to determine the distance to the scene to be observed from the portion 105 of the reflected pulsed optical beam 101. In other words, the distance is determined by emitting a series of short laser pulses onto the scene to be observed, and then collecting the energy backscattered by the illuminated scene. Measuring the time of flight then allows the distance traveled by the second optical beam 101 to be deduced, and thus the distance between the scene and the observation system 1.

[0040] The battery powers the transmitter 100, the amplifier 103, the receiver 104 and the electronic control unit 106.

[0041] Advantageously, the observation system 1 comprises an optical connector 107 and an optical fiber 108. The optical fiber 108 has a first portion 109 connecting the optical connector 107 to the transmitter 100, and a second portion 110 connecting the optical connector 107 to the receiver 104. Preferably, the first portion 109 corresponds to a central portion of the optical fiber 108, and the second portion 110 corresponds to a sheath surrounding the central portion 109. The first and second portions 109, 110 of the optical fiber 108 are configured to allow the propagation of optical radiation, in particular optical radiation in the infrared range.

[0042] The optical connector 107 is configured to transmit the second optical radiation 101. For example, the optical connector 107 has an optical prism 40, preferably a right prism, and a ferrule 41 connecting the optical fiber 108 to the optical prism 40. Thus, the second optical radiation 101 emitted by the emitter 100 propagates in the first part 109 of the optical fiber 108, and the second part 110 of the optical fiber 108 allows the reception of the part 105 of the returned pulsed optical radiation 101.

[0043] The optical prism 40 can be glued onto the ferrule 41. Preferably, a glue-free space, for example an air layer or a void space, is created between the ferrule 41 and the optical prism 40 so as to prevent a laser emission from the second optical radiation 101 from passing through a layer of glue.

[0044] Thus, optical fiber 108 can be used to determine the distance to the scene to be observed. In particular, the use of optical fiber 108 allows the reception and emission of the second optical radiation 101 to be juxtaposed to determine the distance, which reduces the bulk of the observation system 1.

[0045] Furthermore, when it is desired to illuminate the scene to be observed, from a laser-type radiation, the emitter 100 amplifies the second optical radiation 101, using the amplifier 103, which propagates in the first part 109 of the optical fiber 108 towards the optical connector 107.

[0046] Thus, the optical connector 107 provides a single optical interface for the emission and reception of the second optical radiation 101 in order to determine a distance, and for the emission of a laser-type radiation for illumination of the scene to be observed.

[0047] Advantageously, the observation system 1 may include a second optical path 5 comprising an eyepiece 21 and configured to transmit another portion 12 of the first optical radiation 60 transmitted by the optical element 11 to the eyepiece 21. Thus, the scene can be observed directly. More specifically, the system 1 includes a third optical path 10 connecting the main optical path 2 to the second optical path 5. The optical element 11 is further configured to transmit the other portion 12 of the first optical radiation 60 to the third optical path 10. In other words, the optical element 11 is configured to allow a first portion 22 of the first radiation 60 to pass to the main sensor 7, to reflect a second portion 12 of the first optical radiation 60 to the third optical path 10, and to transmit the second optical radiation 101 to the optical device 6. The optical element 11 may be a prism.A prism is defined as a cut glass block comprising at least five faces, or diopters. Preferably, the optical element 11 includes an entrance diopter 72 transparent to infrared light and semi-reflective to visible light. Infrared light has a wavelength between 0.75 micrometers and 100 micrometers, while visible light has a wavelength between 380 nanometers and 750 nanometers. The eyepiece 21 allows visualization of the second part 12 of the first optical beam 60. Thus, an observation system 1 is provided that allows the user's eye 9 to directly view the first visible light 60 emitted by the scene to be observed. The system 1 may also include a display 4 to display, via the second optical channel 5, the digital image from the main sensor 7.The display 4 can be directly coupled to the main sensor 7, via a connection 28.

[0048] Advantageously, system 1 comprises an optical assembly 13 including at least the optical element 11. The optical assembly 13 may further include other optical elements. These other optical elements are denoted optical systems 23, 24, 111. The optical element 11 and the optical systems 23, 24, 111 may be prisms, and the optical assembly 13 is then a prismatic assembly, that is to say, an assembly of prisms. The optical assembly 13 is a particularly simple and rigid structure and allows for simplification while lightening the observation system 1. For example, the optical assembly 13 comprises the optical element 11, a first optical system 23 coupled to the optical element 11, a second optical system 24 coupled to the first optical system 23 and a third optical system 111 coupled to the optical element 11. In general, two optical elements coupled together are understood to be two optical elements which are in contact with each other.They can be fixedly mounted, or removable, one on top of the other. In this embodiment, the optical element 11, the first and third optical systems 23, 111 are respectively three prisms and the second optical system 24 comprises two prisms 70, 71.

[0049] The optical element 11 comprises the input diopter 72, a first output diopter 73, and a second output diopter 112. The first output diopter 73 is transparent to visible light and reflective to infrared light. The second output diopter 112 is neutral and is coupled to the optical prism 40 of the optical connector 107. A neutral diopter is defined as a transparent diopter that allows light to pass through. The input diopter 72 is a semi-reflective mirror for visible light and transparent to infrared light. The input diopter 72 transmits the first part 22 of the first radiation 60 to the main sensor 7, via the first output diopter 73, and the second part 12 of the first optical radiation to the third optical channel 10.The first output diopter 73 transmits, by reflection, the second optical radiation 101 to the input diopter 72 and transmits, by reflection, part 13 of the second optical radiation 101 to the optical prism 40, via the second output diopter 112. Furthermore, the third optical system 111 transmits the first part 22 of the first radiation 60 to the main sensor 7. The third optical system 111 comprises a neutral input diopter 113 coupled to the first output diopter 73 and a neutral output diopter 114 coupled to the main sensor 7.

[0050] The first optical system 23 is configured to transmit the second part 12 of the first optical radiation 60 from the third optical channel 10 to the second optical channel 5. The first optical system 23 includes a first neutral input diopter 74a to receive the first optical radiation 60 and to allow the passage of optical radiation with wavelengths of 101, 13 in the infrared range. The first optical system 23 further includes a second neutral input diopter 74b coupled to the input diopter 72 of the optical element 11 to receive the second part 12 of the radiation. Moreover, the first optical system 23 includes a neutral output diopter 76 and an intermediate diopter 75 reflecting the optical radiation 101, 13, 60.

[0051] The second optical system 24 is designed to establish optical fusion between the digital image from the display 4 and the second part 12 of the first optical beam 60 from the scene to be observed. In other words, the second optical system 24 is configured to transmit the second part 12 of the first optical beam 60 to the eyepiece 21 and to transmit the digital image to the eyepiece 21. The second optical system 24 is an optical splitter. It comprises a first prism 70 having a neutral input diopter 77 coupled to the output diopter 76 of the first optical system 23, and a semi-reflective intermediate diopter 78 to transmit a portion of the second part 12 of the beam to a neutral output diopter 79, corresponding to an output diopter of the optical assembly 13.This output diopter 79 transmits the radiation from the scene to be observed and the digital image to the eyepiece 21, so that the scene and the digital image can be observed. Furthermore, the second optical system 24 includes a second prism 71 having a neutral input diopter 80 coupled to the display 4 and a neutral output diopter 81 coupled to the intermediate diopter 78 of the first prism 70. Thus, the second prism 71 allows the digital image to be transmitted to the output diopter 79 of the optical assembly 13. The second optical path 5 comprises the second optical system 24 and allows observation of the scene from the first optical radiation 60 and the digital image displayed by the display 4. Such an optical assembly 13 makes the observation system 1 sufficiently compact.

[0052] Advantageously, the prisms 11, 23, 70, 71, and 111 of the optical assembly 13 can be bonded together to form a single-piece optical assembly 13. According to yet another advantage, other elements 4, 7, 14, and 40 can be fixedly mounted on the optical assembly 13. Furthermore, when the elements 4, 7, 14, and 40 are fixedly mounted on a single-piece optical assembly 13, the single-piece optical assembly 13 and the fixed elements 4, 7, 14, and 40 form a single-piece assembly 50. A single-piece assembly is defined as an assembly of elements fixed together in such a way that removing one of the elements results in the mechanical destruction of the assembly. Thus, a single-piece assembly 50 is provided that prevents relative movement between the elements of the assembly 50, which can occur, for example, during shocks or vibrations. It is also said that the monobloc assembly 50 has a role as an optical invariant.Advantageously, the first sensor 7, the display 4 and the optical prism 40 of the optical connector 107 are fixedly mounted on the monobloc optical assembly 13.

[0053] This ensures robust harmonization of the first, second, and third optical channels 2, 5, and 10, regardless of any relative displacements between the different elements of the optical channels, particularly displacements relative to a lens 20 located at the input of the first optical channel 2 or to the eyepiece 21 located at the output of the second optical channel 5. The monoblock assembly 50 allows the digital image from the display 4 to be superimposed onto the scene image from the third optical channel 10, i.e., the second part 12 of the first optical beam 60, without any shift between the fields. This image superimposition is also referred to as optical fusion. The monoblock assembly 50 provides robust harmonization, maintaining alignment even in the event of shocks and vibrations. In other words, the monoblock assembly 50 minimizes the risk of deharmonization.

[0054] Advantageously, the optical assembly 13 may include a sighting reticle 14. More specifically, the third optical channel 10 includes the sighting reticle 14. For example, the reticle 14 is a figure deposited on a glass surface by screen printing or photolithography. The reticle 14 may also be made of taut wires. A figure can thus be superimposed on the image of the scene to be observed. The sighting reticle 14 can be mounted on the optical assembly 13, preferably in a fixed manner so as to form part of the monobloc assembly 50. This ensures robust harmonization of the first, second, and third optical channels 2, 5, 10 with the sighting reticle 14 under all relative displacements between the different elements of these optical channels 2, 5, 10. Advantageously, the sighting reticle 14 is fixedly mounted on the output diopter 76 of the first optical system 23.

[0055] According to one variant, the display 4 can be configured to display a sighting reticle in the second optical channel 5. For example, the sighting reticle can be a cross, a circle or more generally a figure allowing identification of the location on the scene of the second optical beam 101. Thus, when the display 4 is fixedly mounted on the optical assembly 13, for example on the input diopter 80 of the second optical system 24, the first, second and third optical channels 2, 5, 10 are harmonized with the displayed sighting reticle.

[0056] System 1 may also include a fourth optical channel 3 capable of receiving a third optical beam 70 emitted by the scene and includes a second sensor 8 configured to construct a digital image from the third optical beam 70. The second sensor 8 is also powered by the battery. Advantageously, system 1 includes an image processing unit 15 coupled to the main sensor 7 via connection 28 and coupled to the display 4 via connection 27. The battery also powers the image processing unit 15 and the display 4. The image processing unit 15 is, for example, a microprocessor. The image processing unit 15 is configured to construct a digital image from the digital images from the main sensor 7 and the second sensor 8, respectively.For example, the digital image is created from a digital fusion between the digital images from the main sensor 7 and the second sensor 8 respectively. The image processing unit 15 is coupled to the first sensor 7 by a connection 16, and to the second sensor 8 by a connection 17. In addition, the image processing unit 15 is coupled to the display 4, by a connection 18, to transmit the third digital image to the display 4.

[0057] The display 4 can also be configured to display a digital image from the digital images from the primary sensor 7 and the second sensor 8, respectively. For example, the first optical channel 2 can be a daytime digital observation channel, meaning that the primary sensor 7 is sensitive to visible light. Advantageously, the fourth optical channel 3 can be a nighttime digital observation channel, meaning that the second sensor 8 is sensitive to infrared, in particular infrared with a wavelength greater than or equal to 700 nm. In another embodiment, the primary sensor 7 is sensitive to infrared light.

[0058] The fourth optical channel 3 can be harmonized with the first digital channel 2 using conventional image processing techniques. Thus, after the digital harmonization of the first and second digital channels 2 and 3, the monoblock assembly 50 allows the first and second digital channels 2 and 3 to be harmonized with the second and third optical channels 5 and 10.

[0059] The observation system 1 advantageously comprises a housing 19 containing the sensors 7, 8, the optical element 11, the display 4, the optical assembly 13, the reticle 14, the image processing unit 15, and the battery. Furthermore, the first optical channel 2 may include the lens 20 mounted on the housing 19. The fourth optical channel 3 may also include an additional lens 26 mounted on the housing 19.

[0060] Furthermore, an observation method can be implemented by the observation system 1 defined above. The method comprises receiving a first optical beam 60 emitted by a scene to be observed via a main optical channel 2 equipped with a main sensor 7 that processes a digital image from the first optical beam 60. The main optical channel 2 includes an optical device 6 for transmitting the first optical beam 60 to the main sensor 7. The method further comprises emitting a second optical beam 101 in the infrared range. The method includes transmitting a portion 22 of the first optical beam 60 to the main sensor 7 and transmitting the second optical beam 101 from the main optical channel 2 to the scene to be observed.

[0061] Advantageously the second optical radiation 101 is of the pulsed type, and the method includes receiving a part 105 of the second pulsed optical radiation 101 returned by the scene to be observed and determining a distance from the scene to be observed from the part 105 of the second pulsed radiation 101 returned.

[0062] A manufacturing method for the observation system 1 is described below. The manufacturing method includes providing the main optical channel 2 and the emitter 100. Furthermore, the method includes mounting the optical element 11 in the main optical channel 2.

[0063] Advantageously, the method includes mounting the optical element 11 within an optical assembly 13, and mounting the main sensor 7 in a fixed manner on the optical assembly 13.

[0064] The method may further include mounting an optical fiber 108 on an optical connector 107 to transmit the second optical beam 101 and to receive the portion 105 of the second pulsed optical beam 101 that is returned. The method then includes mounting the optical connector 107 on the optical assembly 13.

[0065] Advantageously, after mounting the ferrule 41 onto the optical prism 40 of the optical connector 107, the optical connector 107 mounting step involves adjusting the position of the optical connector 107 along an axis parallel to a longitudinal axis A of the ferrule 41. This adjustment optimizes the emission and reception of the pulsed optical radiation to determine the scene distance. During this adjustment, the position of the center of a point formed by the second optical radiation 101 on the scene does not change, but the diameter of the point is modified. Unlike conventional methods, the aim is not to place the optical connector 107 in a position where the diameter of the point is as small as possible. Indeed, if the connector is placed in this position, the divergence of the emission of the second optical radiation 101 is at its lowest, and the returning photons propagate primarily within the first part 109 of the optical fiber 108.These photons are then lost for distance measurement, the coupling between emission and reception decreases, and the measurement becomes less precise. Therefore, the optical connector 107 is positioned to increase the divergence of the emission of the second optical beam 101, thereby increasing the diameter of the point and increasing the number of returning photons within the second part 110 of the optical fiber 108. This improves the coupling between emission and reception, thus enhancing the accuracy of the distance measurement.

[0066] The optical connector 107 assembly step may involve adjusting the position of the optical connector 107 along an axis perpendicular to the longitudinal axis A of the ferrule 41. This adjustment harmonizes the position of the dot formed by the second optical beam 101 on the scene with the aiming reticle 14, i.e., bringing the dot as close as possible to the scene as viewed by the user. The adjustment is performed in such a way as to minimize the relative difference between the position of the dot and the position of the aiming reticle 14. To perform this adjustment, the aiming reticle 14 is illuminated by the lower part of the optical assembly 13. Simultaneously, the second optical beam 101 is emitted. By observing the beams emanating from the optical device 6 at infinity, it is possible to simultaneously view the aiming reticle 14 and the relative position of the dot.The position of the optical connector 107 is then chosen to minimize the difference, as seen by the scope, between the dot and the aiming reticle 14. The two aforementioned adjustments can be made sequentially, one after the other. By making the adjustments along two axes perpendicular to each other, there is little influence of one adjustment on the other.

[0067] The process may include, after at least one of the adjustment steps, fixing the optical connector 107 onto the optical assembly 13.

Claims

1. Observation system comprising: a main optical path (2) capable of receiving a first optical radiation (60) emitted by a scene to be observed and comprising a main sensor (7) configured to devise a digital image from the first optical radiation (60); and an emitter (100) configured to emit a second optical radiation (101) of the infrared domain; the main optical path (2) comprising an optical element (11) configured to transmit a portion (22) of the first optical radiation (60) to the main sensor (7) and to transmit the second optical radiation (101) to the scene to be observed, the observation system comprising an optical connector (107) configured to transmit the second optical radiation (101), an optical fibre (108) connecting the optical connector (107) to the emitter (100), and a second optical path (5) including an eyepiece (21) and shaped to transmit another portion (12) of the first optical radiation (60) transmitted by the optical element (11) to the eyepiece (21), characterised in that the observation system comprises an optical assembly (13) comprising the optical element (11), and wherein the main sensor (7) and the optical connector (107) are fixedly mounted on the optical assembly (13).

2. System according to claim 1, wherein the emitter (100) comprises an amplifier (103) configured to emit the second laser-type optical radiation (101).

3. System according to any one of the preceding claims, wherein the second optical radiation (101) is of the pulsed type, the system furthermore comprising a receiver (104) configured to receive a portion (105) of the second pulsed optical radiation (101) returned by the scene to be observed, and an electronic control unit (106) configured to determine a distance to the scene to be observed based on the returned portion (105) of the second pulsed optical radiation (101).

4. System according to any one of the preceding claims, wherein the optical fibre (108) comprises a first portion (109) connecting the optical connector (107) to the emitter (100), and a second portion (110) connecting the optical connector (107) to the receiver (104).

5. System according to any one of the preceding claims, wherein the optical assembly (13) comprises an optical system (23) configured to transmit the other portion (12) of the first optical radiation (60) to the eyepiece (21), the optical assembly (13) forming a one-piece assembly (50).

6. System according to any one of the preceding claims, wherein the optical assembly (13) comprises a viewing reticle (14).

7. Method for manufacturing an observation system, comprising the provision of a main optical path (2) capable of receiving a first optical radiation (60) emitted by a scene to be observed and comprising a main sensor (7) configured to devise a digital image from the first optical radiation (60), the provision of an emitter (100) configured to emit a second optical radiation (101) of the infrared domain, and a mounting, in the main optical path (2), of an optical element (11) transmitting a portion (22) of the first optical radiation (60) to the main sensor (7) and transmitting the second optical radiation (101) to the scene to be observed, characterised in that the manufacturing method comprises mounting the optical element (11) within an optical assembly (13), mounting the main sensor (7) on the optical assembly (13), mounting an optical fibre (108) on an optical connector (107), and mounting the optical connector (107) on the optical assembly (13).

8. Method according to claim 7, wherein the optical connector (107) comprises an optical prism (40) and a ferrule (41) connecting the optical fibre (108) to the optical prism (40), and the step of mounting the optical connector (107) comprises adjusting a position of the optical connector (107) along an axis parallel to a longitudinal axis (A) of the ferrule (41).

9. Method according to claim 8, wherein the step of mounting the optical connector (107) comprises adjusting a position of the optical connector (107) along an axis perpendicular to the longitudinal axis (A) of the ferrule (41).

10. Method according to claim 9, comprising, before the step of mounting the optical connector (107), mounting a viewing reticle (14) on the optical assembly (13).

11. Method according to any one of claims 8 to 10, comprising, after at least one of the adjustment steps, attaching the optical connector (107) to the optical assembly (13).