Night vision binoculars

Abstract

The present invention relates to night vision binoculars (10) comprising: a. a lens (22) having an optical axis (X-X'), and b. an adjustment device (24) for adjusting the focus of the lens (22), the adjustment device (24) having an adjustment mode, referred to as the progressive mode, in which the focus is adjusted to object planes (Po) not perpendicular to the optical axis (X-X') of the lens (22) so as to allow for near-field focusing on a part of the field of view (Cv) and far-field focusing on another part of the field of view (Cv).

Description

[0001] DESCRIPTION

[0002] TITLE: Night Vision Binoculars

[0003] The present invention relates to night vision binoculars.

[0004] It particularly concerns the focusing devices for the objectives of the optical paths of night vision binoculars.

[0005] The ergonomics of using night vision binoculars directly contributes to the user's viewing comfort and ensures that the binoculars improve the infantryman's night mobility capacity as much as possible while generating the least possible fatigue over time.

[0006] Depending on the user type, the use of control rings is more or less frequent (for example: switching from a focus of more than 10 meters (m) to observe the general direction of movement, to a focus of 1.5 m to 2 m to observe obstacles or other elements of attention close to the feet).

[0007] Binoculars typically available on the market have lenses with a standard field of view of 40° for a numerical aperture of F / 1.2. The lenses are focused manually and according to focusing planes perpendicular to the optical axis. The depth of field of these lenses allows a sharp image to be obtained from 15 m to infinity when the focus is set at 30 m. Thus, for a focus set at 30 m, the image of an object observed at 2 m is blurred.

[0008] In particular, in the case of monocular binoculars, the user looks with a single eye (the so-called intensified eye) through an optical system. Observation through this eye requires the manipulation of a control ring in order to adjust the focus on variable fields of focus. The non-intensified eye retains its ability to accommodate on the near field or the far field. In the case of bi-ocular devices, the user looks with both eyes at an intensified image captured by a single objective. Observation requires the manipulation of a control ring in order to adjust the focus on the variable fields of focus. In the case of binocular devices, the user looks through two independent optical paths, each comprising an intensifier tube. In this case, the user has a stereoscopic vision of the observed scene.Observation requires the manipulation of two control rings to adjust the focus of each optical path over the variable focus fields. Thus, when the user moves, such lenses require the manipulation of a lens focus control ring to sharpen the image of an object or scene plane to be observed.

[0009] The market for night vision binoculars is evolving and tends towards increasing fields and numerical aperture without loss of resolution while reducing the weight of equipment and increasing user ergonomics. This evolution leads to the proposal of new, more complex optical architectures that can integrate new functionalities.

[0010] However, the solutions identified in the state of the art offering autofocus or depth of field increase devices have limitations when implemented in a hands-free night vision system (real-time imaging).

[0011] In particular, solutions to increase depth of field are based on the use of variable aperture diaphragms. The smaller the aperture, the greater the depth of field. The trade-off is a significant loss of luminous flux, making the system unusable at deep night levels (night level 4 to 5 illuminance < 1 mlux on low albedo stage).

[0012] Solutions incorporating autofocus require digital image analysis combined with motorized focus of the lens. However, digital analysis requires sampling flux from the useful flux incident on the tube, thus reducing the usability in deep night level. The sensor allowing the acquisition of the digital image must itself be a low light level sensor with sufficient resolution and sensitivity (night 4 to 5), which is not achieved by the state of the art. In addition, the consumption associated with digital analysis and motorized focus is likely to considerably reduce the autonomy of a night vision binocular.

[0013] Solutions incorporating telemetry to determine the distance of the object to be observed are emissive and therefore likely to reduce discretion when using the equipment.

[0014] Finally, solutions based on the use of coupled phase filters and a deconvolution algorithm are only relevant in the case of digital image capture, and not in other cases.

[0015] There is therefore a need for night vision binoculars that facilitate the movement of a user moving in an environment where the objects observed are both far away and close to the objective of the binoculars.

[0016] For this purpose, the present description relates to night vision binoculars comprising: a. an objective having an optical axis, and b. a device for adjusting the focus of the objective, the adjustment device having an adjustment mode, called progressive mode, in which the focus is carried out on object planes not perpendicular to the optical axis of the objective so as to allow near-field focusing on a part of the field of vision and far-field focusing on another part of the field of vision. According to particular embodiments, the binoculars comprise one or more of the following characteristics, taken in isolation or in all technically possible combinations:

[0017] - the adjustment device comprises a first unit for adjusting the focusing distance and a second unit for adjusting the angle between the optical axis and the normal to the object plane;

[0018] - the adjustment device also has an adjustment mode, called classic mode, in which focusing is carried out on object planes perpendicular to the optical axis;

[0019] - the second adjustment unit comprises two optical components of complementary shapes attached to each other, at least one optical component, called the first component, being movable in rotation relative to the other optical component, called the second component, so as to modify the angle between the normal to the object plane and the optical axis, making it possible to modify the difference in focus between the top of the field of vision and the bottom of the field of vision vertically, called the progressive effect;

[0020] - the second adjustment unit has at least: a. a configuration, called classic, corresponding to the classic mode of the adjustment device, the classic configuration corresponding to a positioning of the first component relative to the second component such that the angle between the optical axis and the normal to the object plane is zero, thus making it possible to achieve focusing on a plane perpendicular to the object plane, b. a configuration, called maximum progressive, corresponding to the progressive mode of the adjustment device, the maximum progressive configuration being a rotation of the first component of 180 degrees relative to the classic configuration so that the progressive effect is maximum;

[0021] - the second adjustment unit has at least one configuration, called intermediate progressive, corresponding to: a. a first rotation of the first component by an angle strictly between 0° and 180° relative to the conventional configuration so as to obtain an intermediate progressive effect relative to the conventional configuration and the maximum progressive configuration, and b. a second rotation making it possible to jointly rotate the first component and the second component, until the far-field focus is at the top of the field of vision and the near-field focus is at the bottom of the field of vision;

[0022] - the two optical components are chosen such that the progressive effect, induced by the rotation of at least one of the optical components, is linear over the extent of the vertical field;

[0023] - the two optical components are two prismatic blades;

[0024] - the two optical components are chosen such that the progressive effect, induced by the rotation of at least one of the optical components, is non-linear over the extent of the vertical field;

[0025] -the two optical components are two lenses, for example, spherical, aspherical or Freeform.

[0026] Other characteristics and advantages of the invention will appear on reading the following description of embodiments of the invention, given by way of example only and with reference to the drawings which are:

[0027] [Fig 1], Figure 1, a schematic representation of an example of a night vision binocular comprising an objective lens and a device for adjusting the focus of the objective lens,

[0028] [Fig 2], Figure 2, a schematic representation of the focusing distances for different areas of the field of view,

[0029] [Fig 3], Figure 3, a schematic representation of an example of a unit for adjusting the angle between the optical axis and the normal to the object plane, the adjustment unit being shown in three distinct configurations,

[0030] [Fig 4], Figure 4, a schematic representation of another example of a unit for adjusting the angle between the optical axis and the normal to the object plane, the adjustment unit being shown in three distinct configurations,

[0031] [Fig 5], Figure 5, a schematic representation of a mechanism suitable for pivoting one of the optical components of the adjustment unit, allowing the angle between the optical axis and the normal to the object plane to be modified, and

[0032] [Fig 6], Figure 6, a schematic representation of a mechanism capable of pivoting, on the one hand, one of the optical components of the adjustment unit relative to the other optical component, and, on the other hand, the two optical components together, so as to modify the angle between the optical axis and the normal to the object plane. In the remainder of the description and in the drawings, the distances denoted "d" and "D" are expressed in diopters, and the distances "1 / d" and "1 / D" are the corresponding distances in meters.

[0033] Night vision binoculars 10 are schematically illustrated in Figure 1.

[0034] The binoculars 10 are, for example, intended to be mounted on a helmet or head harness. Alternatively, the binoculars 10 are carried by hand by the user.

[0035] Night vision binoculars 10 are any type of night vision binoculars, including monocular binoculars, binocular binoculars, binocular binoculars, or panoramic binoculars (4-way intensified). Binoculars 10 can also be connected binoculars and integrate data visualization elements.

[0036] As illustrated in FIG. 1, the binoculars 10 comprise an eyepiece 20, an objective lens 22 and a device 24 for adjusting the focus of the objective lens 22.

[0037] The objective 22 is an optical system typically comprising one or more optical elements (lenses, mirrors, etc.), as well as a light intensification device (tube). The objective 22 has an optical axis X-X' shown in Figure 1.

[0038] The adjustment device 24 is capable of being manipulated by the user to adjust the focus of the lens 22 on an object plane Po of the scene. In particular, the adjustment device 24 is configurable by the user to adjust the focus distance 1 / D. The focus distance 1 / D is the distance between the lens 22 and the intersection of the object plane Po with the optical axis X-X'. The focus distance is typically adjusted for the center of the field of view (the center of the field of view must be sharp at the focus distance 1 / D). Thus, for focusing on an object plane perpendicular to the optical axis, the entire field of view is sharp at the distance 1 / D. This is not the case when focusing has been achieved on an object plane not perpendicular to the optical axis: the top of the field will typically be sharp at a distance greater than the 1 / D distance, and the bottom of the field will be sharp at a distance smaller than the 1 / D distance.In this case, only the central area of ​​the field of vision will be sharp at distance 1 / D.

[0039] The adjustment device 24 has an adjustment mode, called progressive mode, in which the focusing is carried out on object planes Po not perpendicular to the optical axis X-X' of the lens 22 (see figure 1) so as to allow near-field focusing on a part of the field of vision C and far-field focusing on another part of the field of vision Cv. By far-field focusing, it is understood that the focusing is carried out on an object far from the user, typically more than 10 meters, or less than 0.1 diopter. By near-field focusing, it is understood that the focusing is carried out on an object close to the user, typically between 1 m and 3 m, or between 0.33 and 1 diopter.Thus, in the progressive mode, the difference in focus between the top of the field of view Cv (upper part at the end of the field of view) and the bottom of the field of view Cv (lower part at the end of the field of view) in vertical, called progressive effect, is non-zero. It depends on the angle (p between the optical axis X-X' and the normal N to the object plane P. o .

[0040] More precisely, considering the field of vision C along the vertical, the far-field focus is carried out on the high zone ZH of the field of vision C v , and the near-field focusing is performed on the low zone ZB of the field of view C v Figure 1 schematically illustrates different zones of the field of vision Cv, namely high zone ZH, central zone Zc, and low zone ZB., as well as the progressive effect ±d in vertical (in diopters).

[0041] In particular, as illustrated by Figure 2, for a lens 22 located at a height H from the ground, and a linear variation of the progressive effect of ±d (diopters) vertically relative to the center of the field of vision Cv, the focus is sharp: at the center of the field of vision at a distance 1 / D, or D in diopters, sharp at the lower end of the field of vision Cv (lower part) at a distance expressed in diopters of (D+d), and sharp at the upper end of the field of vision Cv (upper part) at a distance expressed in diopters of (Dd).

[0042] Preferably, the adjustment device 24 also has an adjustment mode, called classic mode, in which the focusing is carried out on object planes Po perpendicular to the optical axis X-X'. In the classic mode, the vertical focusing is uniform over the field of vision Cv (zero progressive effect).

[0043] As illustrated by the example of FIG. 1, the adjustment device 24 comprises a first unit 30 for adjusting the focusing distance 1 / D (D in diopters) and a second unit 32 for adjusting the angle (p between the optical axis X-X' and the normal N to the object plane Po.

[0044] The first adjustment unit 30 is capable of being controlled by the user. The first adjustment unit 30 is typically a mechanism for manually adjusting the focusing distance 1 / D (distance between the objective 22 and the intersection of the object plane Po with the optical axis X-X') depending on the target object. The objective 22 is typically mounted in a barrel, and the first adjustment unit 30 makes it possible to move the barrel of the objective 22 in translation to focus on a target object.

[0045] The second adjustment unit 32 is an added unit compared to traditional night vision binoculars. In other words, the eyepiece 20, the objective lens 22 and the first adjustment unit 30 are conventional elements of night vision binoculars, but the second adjustment unit 32 is not.

[0046] The second adjustment unit 32 is suitable for being controlled by the user.

[0047] Preferably, the second unit 32 is capable of allowing the transition from progressive mode to classic mode, and vice versa.

[0048] In exemplary embodiments illustrated by Figures 2 and 3, the second adjustment unit 32 comprises two optical components 40, 42 of complementary shapes attached to each other. At least one optical component, called the first component 40, is rotatable relative to the other optical component, called the second component 42, so as to modify the angle (p between the normal N to the object plane Po and the optical axis X-X'. The rotation is carried out around an axis substantially parallel to the optical axis X-X'. The modification of this angle (p) makes it possible to modify the progressive effect (difference in focus between the top of the field of vision Cv and the bottom of the field of vision Cv in vertical). In practice, the two optical components 40, 42 are mounted in at least one barrel indexed on the objective 22 (centered on the optical axis X-X' of the objective 22).

[0049] The two component blades 40, 42 are, for example, made of glass or polycarbonate.

[0050] Preferably, the two components 40, 42 are furthermore rotatable together. This makes it possible to bring the far-field focus to the top of the field of view Cv and the near-field focus to the bottom of the field of view Cv. This is useful in the case where the rotation of the first component 40 relative to the second component 42 makes it possible to obtain different progressive effects.

[0051] Preferably, the two optical components 40, 42 are positioned in a ray focusing zone of the objective 22. More precisely, the two optical components 40, 42 are positioned close to the image plane of the objective 22 or an intermediate image plane of the objective 22.

[0052] Preferably, the two optical components 40, 42 are chosen such that the progressive effect, induced by the rotation of at least one of the components, is linear over the extent of the vertical field. By linear, it is understood that the variations in progressive effect are continuous over the extent of the vertical field of vision Cv. The two optical components 40, 42 are, for example, two prismatic plates of the same prismatic angle, thus forming a diasporameter. In this case, the two plates are preferably slightly inclined, that is to say that the total prismatic angle of the two plates is small, typically less than 5 degrees, preferably less than or equal to 2 degrees.

[0053] Alternatively, the two optical components 40, 42 are chosen such that the progressive effect, induced by the rotation of at least one of the components, is non-linear over the extent of the vertical field. The two optical components 40, 42 are, for example, two lenses, thus forming a doublet. The lenses are, for example, spherical, aspherical or Freeform.

[0054] Preferably, the second adjustment unit 32 has at least one configuration, called classic, and one configuration, called maximum progressive.

[0055] The classic configuration corresponds to the classic mode of the adjustment device 24. The classic configuration corresponds to a positioning of the first component 40 relative to the second component 42 such that the angle (p between the optical axis X-X' and the normal N to the object plane Po is zero, thus making it possible to focus on a plane perpendicular to the object plane Po (zero progressive effect).

[0056] Such a configuration is obtained in the left-hand representations of figures 2 and 3. In particular, the two prismatic blades of figure 3 and the two lenses of figure 4 are in opposition (head to tail) so as not to generate a difference in optical path for two parallel light rays incident on the two optical components 40, 42.

[0057] The maximum progressive configuration corresponds to the progressive mode of the adjustment device 24. The maximum progressive configuration corresponds to a rotation of the first component 40 of 180 degrees relative to the conventional configuration so that the progressive effect is maximum.

[0058] Such a configuration is obtained in the center and right representations of figures 2 and 3. In particular, in these representations, the two prismatic blades of figure 3 and the two lenses of figure 4 are opposite each other, making it possible to generate a maximum optical path difference for two parallel light rays incident on the two optical components 40, 42. In particular, with respect to the center representations, the two optical components 40, 42 of the right representations are rotated together by 180°.

[0059] In particular, in the case of prismatic plates, for two plates of index n, height Y and for a prismatic angle of 0 cumulative on the two plates, the maximum difference in optical path is obtained in the case where the two plates are opposite each other. The maximum difference A between the diametrically opposite optical paths is given by the following formula:

[0060] A= (n — 1) * Y * tan(0)

[0061] The focus difference 2d (expressed in diopters) between the top of the field and the bottom of the field (±d relative to the center of the field), expressed in diopters, and called the progressive effect, is given by the following formula: Where F is the focal length of the lens 22

[0062] The progressive effect, expressed in diopters, is here linear as a function of the vertical field.

[0063] Furthermore, as illustrated in Figure 2, the focusing distances being expressed in diopters relative to the position of the lens 22, and by expressing in polar coordinates the straight line “focusing plane” (equivalent to the ground in Figure 2), the angle (p is expressed as a function of the 1 / 2 field angle a of the lens 22, the progressiveness range + / - d and the focusing in the middle of the range D diopters:

[0064] D tan(<») = — sin(a) d

[0065] For example, for blades with index n=1.5, height Y=10 mm, forming a cumulative prismatic angle 0=15°, and a 22 objective with focal length F=20.4 mm with a half-field of vision a=25°, we obtain:

[0066] - A=0.26 mm,

[0067] - 2d=0.630 diopters,

[0068] - rp=23° for focusing in the center of the field at a distance, and

[0069] - D = 0.318 diopters.

[0070] In this case, when the user tilts his head 23° towards the ground, he has a clear vision at more than 300m on the top of the field of vision Cv of the binoculars 10, a clear vision at 3.1m in the center of the field, and a clear vision on the bottom of the field of vision Cv at 1.6m. This distribution of the perceived sharpness in the field is comparable to the sharpness perceived through a progressive lens.

[0071] For the same progressive effect, if the user chooses a mid-focus at 2m, then the progressive effect is as follows: clear vision at about 5m at the top of the field of view Cv, at 2m in the center of the field of view Cv, and at 1.2m at the bottom of the field of view Cv.

[0072] Note that the transverse shift induces a parallelism defect x between the input and the output of the optical path which is proportional to the distance T and to the average index of the medium N which separates the last diopter of the diasporameter from the image plane: x = T. tan (n - 1) Nevertheless, this effect is negligible in the case of the present invention.

[0073] In particular, Figure 5 illustrates the body of the lens 22 with a holding ring 50 also holding one of the optical components 40, 42. The other optical component is rotatable via a pivoting mechanism 60 (barrel in which the first component 40 is mounted, the barrel being rotatable via an external control). Thus, in this example, only one of the optical components 40, 42 is movable and only two configurations are possible: the conventional configuration, and the maximum progressive configuration (180° rotation of the movable optical component). The transition from one to the other is, for example, validated by a ratchet or a stop.

[0074] Preferably, the second adjustment unit 32 has at least one configuration, called intermediate progressive, corresponding to:

[0075] - a first rotation of the first component 40 by an angle strictly between 0° and 180° relative to the conventional configuration so as to obtain an intermediate progressive effect relative to the conventional configuration and the maximum progressive configuration, and

[0076] - a second joint rotation of the first component 40 and the second component 42 so that the far-field focus is on the upper part (high part) of the field of vision and the near-field focus is on the lower part (low part) of the field of vision.

[0077] In particular, Figure 6 illustrates the body of the lens 22 with a holding ring 50. A first pivoting mechanism 62 (barrel in which the first component 40 is mounted, the barrel being pivotable in rotation via an external control) is suitable for pivoting the first component 40. A second pivoting mechanism 64 (barrel in which the second component 42 is mounted, the barrel being pivotable in rotation via an external control) is suitable for pivoting both the first and second components 42. Thus, in this example, the first component 40 is movable relative to the second component 42, making it possible to adapt the angle (p between the optical axis X-X' and the normal N to the object plane P oThe possibility of jointly rotating the first component 40 and the second component 42 makes it possible to reorient the focus so that the top of the field of vision C corresponds to a far-field focus, and the bottom of the field of vision Cv corresponds to a near-field focus.

[0078] In another implementation variant, the second adjustment unit 32 is a prism. In this case, the prism introduces a permanent optical path difference for parallel rays incident on the prism, and therefore a permanent non-zero angle (p) between the normal N to the object plane Po and the optical axis X-X'. Thus, in this case, the adjustment device 24 operates only according to the progressive adjustment mode (and not the conventional adjustment mode). If the prism is not rotatable, the progressive effect is, in addition, fixed.

[0079] An example of focusing the objective lens 22 of the night vision binoculars 10 is illustrated in the following.

[0080] First, the user wishing to focus with a progressive effect (progressive adjustment mode) operates the first adjustment unit 30, and adapts the focusing distance 1 / D to be sharp at least in an area of ​​the field of view Cv, typically in an area in the center of the field of view Cv.

[0081] Then, the user manipulates the mechanism (60 in Figure 5 and 62 in Figure 6) making it possible to rotate the first component 40 relative to the second component 42, so as to introduce a progressive effect if the previous adjustment mode was a conventional adjustment mode, and to adjust (when possible) the amplitude of the progressive effect.

[0082] Optionally, in cases where the second adjustment unit 32 allows an intermediate progressive configuration to be obtained (figure 6 for example), the user actuates a mechanism (64 in figure 6) allowing the first component 40 and the second component 42 to be rotated jointly, until the far-field focus is at the top of the field of vision Cv in vertical and the near-field focus is at the bottom of the field of vision C in vertical.

[0083] In the case of the embodiment of Figure 5, the user thus manipulates two controls. In the case of the embodiment of Figure 6, the user manipulates three controls.

[0084] A user wishing to perform a focus in conventional mode, manipulates the mechanism (60 in Figure 5 and 62 in Figure 6) allowing the first component 40 to be rotated relative to the second component 42, until the progressive effect is zero. He then adjusts the focus on an object plane Po perpendicular to the optical axis X-X' via the first adjustment unit 30. Note that the transition from a conventional mode to a progressive mode, and vice versa, can be carried out only when this is possible (in the case of the prism alone, only the progressive adjustment mode is possible).

[0085] Thus, the device 24 for adjusting the binoculars 10 makes it possible to focus on object planes Po that are not perpendicular to the optical axis X-X', thus making it possible to obtain a difference in focus between the top of the field of vision Cv and the bottom of the field of vision Cv (progressive effect). This progressive effect makes it easier for a user to move around in an environment where the objects observed are both distant and close to the objective 22 of the binoculars 10 (typically between 20 m and 1 m). In particular, once the focus has been achieved, the user can clearly view, by simply moving the head or eye, a near area or a far area of ​​the observed scene, without having to continually manipulate a focus control ring. With regard to the ergonomics of use, a parallel can be drawn with the use of progressive lenses in everyday life.

[0086] In embodiments where the blades are adjustable, the progressive effect is furthermore adaptable by the user, allowing him to choose between a classic focusing mode (no progressive effect) and a progressive mode by giving him the possibility of choosing the degree of progressiveness.

[0087] Such an adjustment device 24 can be integrated into any type of existing night vision binoculars. In particular, it does not reduce the numerical aperture and does not introduce vignetting. The night use capabilities of levels 4 to 5 are fully preserved. In addition, it does not require motorization so that the autonomy of the binoculars is not impacted. The solution also preserves the discretion of use.

[0088] Those skilled in the art will understand that the embodiments and variants previously described can be combined with each other provided that they are technically compatible.

Claims

CLAIMS . Night vision binoculars (10) comprising: a. an objective (22) having an optical axis (X-X'), and b. an adjustment device (24) for the focus of the objective (22), the adjustment device (24) having an adjustment mode, called progressive mode, in which the focus is carried out on object planes (P o ) not perpendicular to the optical axis (X-X') of the objective (22) so as to allow near-field focusing on a part of the field of vision (Cv) and far-field focusing on another part of the field of vision (Cv). Binoculars (10) according to claim 1, in which the adjustment device (24) comprises a first adjustment unit (30) for the focusing distance and a second adjustment unit (32) for the angle ( <p) entre l’axe optique (x-x’) et la normale (n) au plan objet (po). . jumelles (10) selon revendication 1 ou 2, dans lesquelles le dispositif de réglage (24) présente, en outre, un mode réglage, dit classique, lequel mise point est réalisée sur des plans objets (po) perpendiculaires à (x-x’). 2 3, seconde unité (32) comprend deux composants optiques (40, 42) formes complémentaires accolés l’un l’autre, moins composant optique, premier (40), étant mobile rotation par rapport l’autre second (42), sorte modifier l’angle (<p) (x-x’), permettant différence haut du champ vision (cv) bas vertical, dite effet progressif. les revendications 3 4, présente : a. une configuration, correspondant classique (24), configuration positionnement (40) (42) tel que nul, ainsi réaliser perpendiculaire (po),b. a configuration, called maximum progressive, corresponding to the progressive mode of the adjustment device (24), the maximum progressive configuration being a rotation of the first component (40) of 180 degrees relative to the conventional configuration so that the progressive effect is maximum. Binoculars (10) according to claim 5, in which the second adjustment unit (32) has at least one configuration, called intermediate progressive, corresponding to: a. a first rotation of the first component (40) of an angle strictly between 0° and 180° relative to the conventional configuration so as to obtain an intermediate progressive effect relative to the conventional configuration and the maximum progressive configuration, and b.a second rotation for jointly rotating the first component (40) and the second component (42), until the far-field focus is at the top of the field of view (Cv) and the near-field focus is at the bottom of the field of view (Cv). . Binoculars (10) according to any one of claims 4 to 6, wherein the two optical components (40, 42) are chosen such that the progressive effect, induced by the rotation of at least one of the optical components (40, 42), is linear over the extent of the vertical field. . Binoculars (10) according to claims 4 to 7, wherein the two optical components (40, 42) are two prismatic plates. . Binoculars (10) according to any one of claims 4 to 6, in which the two optical components (40, 42) are chosen such that the progressive effect, induced by the rotation of at least one of the optical components (40, 42), is non-linear over the extent of the vertical field.Binoculars (10) according to claims 4 to 6 or 9, wherein the two optical components (40, 42) are two lenses, for example, spherical, aspherical or Freeform.

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