Fastening system for securing optical elements

Abstract

The present invention relates to a fastening system for securing an optical element, an optical assembly, a method for securing an optical element, and a method for assembling and aligning an optical assembly. Specifically, the invention relates to a fastening system for securing optical elements for a camera intended for being placed in a satellite orbiting in space.

Description

[0001] FASTENING SYSTEM FOR SECURING OPTICAL ELEMENTS

[0002] DESCRIPTION

[0003] OBJECT OF THE INVENTION

[0004] The present invention relates to a system and a method for securing optical elements. Specifically, the invention relates to a fastening system for securing optical elements for a camera intended for being placed in a satellite orbiting in space.

[0005] BACKGROUND OF THE INVENTION

[0006] There are currently solutions for securing mirrors or lenses based on mechanical elements or even by means of flexible elements glued directly to the perimeter of the mirrors or lenses. However, securing elements of this type are rendered invalid when they are exposed to different forces, since stresses are introduced at the securing points, and can therefore affect the lenses. As a result, it may cause misalignment of the optical elements, deformation, or breakage, generating image distortions and chromatic aberrations, which are caused by light scattering in the lens, resulting in a blurred image with colored edges. Furthermore, the lens may undergo deformations due to said stresses, which can affect image quality, even causing breakages.

[0007] A satellite is an object that has been intentionally placed in orbit and orbits the Earth or another celestial object. These devices are used for many purposes and applications, such as communication, earth observation, navigation, scientific research, and space exploration. Depending on such applications, the most common are earth observation satellites, both civil and military, communication satellites, navigation satellites, and meteorological satellites.

[0008] Earth observation satellites are artificial satellites designed to observe the Earth from an orbit, for example, with applications such as environmental control, meteorology, cartography, etc. Satellites of this type are divided, according to their orbit, into low orbit satellites and geostationary orbit satellites. Low orbit satellites are those comprising an orbit between 200 and 1200 km above the earth’s surface. This means that they have periods comprised between 90 minutes and 5 hours to analyze the earth's surface. For this reason, low orbit satellites are excellent for exhaustive scanning such as fire detection, biomass determination, or ozone layer studies, among others.

[0009] Due to the foregoing, the assembly of an optical assembly to be placed in a satellite and subsequently exposed to in-orbit and launch conditions is a critical step in which not only is it important to fix the assembly in a proper and correct manner, but it is equally important not to introduce aberrations that may degrade the image to be captured. Furthermore, these fastening systems must withstand the conditions to which the system is subjected during launch and in orbit, such as vibrations, vacuum conditions, temperature variations, and launch loads.

[0010] Satellites comprising cameras and optical arrays open up possibilities for different applications in the environmental and energy fields, such as methane gas emission control. With a frequency of 20 images per second, the cameras provide high-resolution images of the Earth that serve a wide range of applications. For example, detecting floating plastics in the sea, monitoring algae blooms, or preventing forest fires are just a few examples of the uses of this novel technology.

[0011] Based on the above, the object of the invention is to develop a fastening system for securing at least one optical element and an optical assembly which is valid to ensure the correct operation of the camera installed in an orbiting satellite.

[0012] DESCRIPTION OF THE INVENTION

[0013] The present invention proposes a solution to the preceding problems by means of a fastening system for securing at least one optical element according to claim 1 , an optical assembly according to claim 9, a fastening method for securing the optical element according to claim 11 , a method for assembling and aligning an optical assembly according to claim 12, and a camera for microsatellites and / or satellites according to claim 13.

[0014] A first inventive aspect provides a fastening system for securing at least one optical element with an outer perimeter of length L2 to a first or second structure of an optical assembly, the fastening system comprising

[0015] - a frame with an inner perimeter of length L3, with L3 > L2, said frame being concentric and configured to be fixed around the outer perimeter of the optical element, comprising a frame axis, an inner surface in turn comprising at least three regions configured to fix the optical element and an outer surface comprising at least three fixing portions, and

[0016] - at least three flexible attachment elements for attachment with the first structure or second structure coupled respectively in each fixing portion.

[0017] The described fastening system is designed for securing at least one optical element of at least one optical assembly of a camera developed to obtain images in the earth’s orbit. The fastening system must be durable so as to withstand the temperature, pressure, and vibration conditions that arise during launch and in orbit.

[0018] The optical element is a known element in cameras and commonly referred to as lens. However, due to the field of application, to the conditions to which it will be exposed, and to the fact that a lens or optical element is a fragile element, the fastening system of the invention must be strong and durable, but without breaking or damaging the optical element or introducing aberrations therein which distort the images to be obtained.

[0019] The purpose of the fastening system is to secure an optical element to a structure that will be part of the final optical assembly, specifically a camera or generator of high- and very high-resolution optical images for earth observation satellites with video capability. In turn, the optical assembly comprises at least two structures, each with at least one fastening system with an optical element, wherein the structures are attached by at least one set of rods and the optical elements of the fastening system are aligned with one another, such that the optical elements comprise the same optical axis.

[0020] The frame is a support structure configured to be fixed around the outer perimeter of the optical element. In the context of the present invention, the configuration for fixing the frame around the outer perimeter of the optical element shall be understood as a direct or indirect attachment or fixing, that is, directly without any additional element or indirectly by means of an additional element, wherein the frame secures or immobilizes the optical element such that it is secured or anchored to the frame, such that the stability and suitable operation of both elements as a whole is guaranteed.

[0021] The frame comprises an inner perimeter having a length slightly greater than the outer perimeter of the optical element, with both elements therefore being concentric, generating a space or gap between both for an additional fixing element, resulting in the elements being fitted with respect to one another.

[0022] The frame comprises a frame axis in the center of the inner perimeter, an inner surface, and an outer surface, wherein the outer surface comprises at least three fixing portions through which the system for fixing to the structure will be fixed. As part of the invention, the fastening system also comprises at least three flexible attachment elements which are in charge of fixing the assembly formed by the frame and the optical element to the first structure or the second structure by means of the coupling of the flexible attachment element in each fixing portion of the frame. Specifically, the flexible attachment elements are longitudinal elements that are introduced in the fixing portions of the frame and in a receiving area of the first or second structure of an optical assembly.

[0023] The inner surface in turn comprises at least three regions configured to fix the optical element, i.e., configured to receive an intermediate element for fixing the optical element.

[0024] In a preferred embodiment, the optical element and the frame comprise a perimeter of the same shape.

[0025] In an embodiment of the fastening system, the at least three fixing portions are located on the outer surface, perpendicular to the frame axis, and have a through hole, and the frame comprises

[0026] - at least one hole, and

[0027] - at least three protrusions, each protrusion projecting in a direction perpendicular to the frame axis from the outer surface to the inner surface of the frame and arranged above a hole.

[0028] The fixing portions of the frame are perpendicular portions projecting outwardly from the outer surface of the frame, that is, in a radial direction away from the axis of the frame, comprising at least one through hole to receive a tubular area of the flexible attachment element for fixing the frame to the first or second structure.

[0029] In addition to the fixing portions, the frame comprises at least three perpendicular protrusions projecting from the inner surface and towards the axis of the frame. These protrusions are located above at least one hole that goes through the frame, i.e., in an upper position with respect to said hole, wherein furthermore the hole is located in a region of the frame the inner surface of which is configured to fix the optical element inside the frame.

[0030] In one embodiment, the protrusions are located in a recessed area of the frame. The presence of this recessed area facilitates the subsequent placement of the additional element for the indirect attachment or fixing of the optical element to the frame.

[0031] Optionally, the protrusions and the hole of the inner region are located diametrically opposite the fixing portion of the frame. This placement allows dispelling the stresses transmitted from the flexible attachment elements, through the frame, to the optical element, such that the optical element is protected from unnecessary aberrations or stresses.

[0032] In a particular embodiment, the at least three fixing portions located on the outer surface of the frame are spaced uniformly along the outer perimeter of the frame. In another embodiment, the at least three protrusions are spaced uniformly along the inner perimeter of the frame. In a particular embodiment, each of the three protrusions is located substantially in the center of the space between every two fixing portions located on the outer surface of the frame.

[0033] In an embodiment of the fastening system, the inner surface of the frame comprises at least three regions configured to receive an adhesive for fixing the optical element. The at least three regions are located on the inner surface of the frame where there is located the hole through which the adhesive is introduced or injected to the inner surface and is housed and fixed between the frame and the optical element.

[0034] In one embodiment, the three regions configured to receive the adhesive coincide with the recessed areas of the frame. Stops are placed in said recessed areas of the frame to control the amount of adhesive to be received.

[0035] Preferably, the adhesive used is a bicomponent adhesive. A bicomponent adhesive is a type of adhesive consisting of two separate components that must be mixed before use. These two components are usually a resin and a hardener that must be mixed in equal parts before application, achieving the hardening thereof and the fixing of the optical element to the frame. By means of this adhesive, an indirect fixing which provides a securing that is strong and durable in the adverse conditions that the optical assembly fastening system experiences both during launch and in orbit is achieved.

[0036] In this way, the frame is attached to the optical element by means of the adhesive in an area different from the area where the frame is attached to the structure, such that the loads supported by the orbiting optical assembly are distributed, and therefore the optical element fastening system improves the known systems, since no aberrations are introduced.

[0037] In one embodiment, the adhesive used for fixing the optical element to the frame is an elastomer, preferably a silicone.

[0038] Elastomers are a specific type of polymer which exhibits elastic and flexible properties, allowing part of the loads and deformations to be absorbed and not transmitting same directly to the optical element.

[0039] In another particular embodiment of the fastening system, the frame has an annular configuration, and the inner surface of the frame is flat and parallel to the frame axis. In this embodiment, the frame is a flat ring, wherein the inner surface is parallel to the outer surface of the optical element, with both surfaces being parallel, and given that the inner perimeter of the frame is greater than the outer perimeter of the optical element, the adhesive is introduced between the surfaces for fixing the optical element to the frame.

[0040] Other configurations and shapes of the frame which allow fixing to the optical element and comprising fixing portions necessary to fix the optical element fastening system to a first or second structure are also possible, such as, for example, the surface of the frame may be curved or inclined.

[0041] In a particular embodiment of the fastening systemeach flexible attachment element comprises

[0042] - a first tubular area configured to be introduced through the through hole of each fixing portion of the frame,

[0043] - a second tubular area configured to be introduced in a receiving area configured to that end in the first or second structure of the optical assembly, and

[0044] - a flexible region arranged between the first and second tubular areas,

[0045] - at least one fixing element that can be coupled at each of the ends of the first and second tubular areas configured to fix the first tubular area and the fixing portion and the second tubular area and the first or second structure.

[0046] As a result of the flexible attachment elements and specifically the tubular areas and the fixing elements of the flexible attachment elements, the fastening system and the first or second structure of the optical assembly can be attached. The first tubular area is fixed to the frame by means of at least one fixing element on the fixing portion of the frame, whereas the flexible region and the second tubular area are received by a receiving area of the first or second structure and wherein the first or second structure is fixed to the fastening system by means of at least one fixing element on the lower part of the first or second structure. In turn, the flexible region allows compensating for small misalignments in situations where the frame and optical element assembly is not perfectly aligned with the first or second structure, allowing an effective fixing without forcing the different elements. Similarly, the flexible region can act as a vibration and noise insulation, reducing the transmission of possible vibrations and noise to the frame and optical element assembly.

[0047] In conclusion, the flexible attachment elements absorb deformations when assembling the fastening system and the optical element to the structure, allowing the optics to be aligned correctly and without aberrations.

[0048] In a preferred embodiment, the tubular area of the flexible attachment element comprises a threaded surface and the fixing elements of the flexible attachment elements are a nut, or a nut with a washer, which can be threaded on said threaded surface.

[0049] The first or second structure are base structures for housing the fastening system and the optical element, comprising an inner housing with a shape equal to the fastening system. The structure comprises at least one receiving area to receive at least one fixing portion and at least one flexible attachment element of the frame, and at least three fixing holes.

[0050] In a preferred embodiment, the structure comprises as many receiving areas as fixing portions comprised in the fastening system. Preferably, the fastening system comprises three fixing portions and three receiving area structures.

[0051] In a preferred embodiment, the frame of the fastening system is made of a material selected from metal, composite, and plastic.

[0052] Based on the above, the designed fastening system allows securing an optical element intended to be mounted in a satellite and to withstand spatial conditions when said satellite is launched and in orbit.

[0053] In a second inventive aspect, the invention provides an optical assembly comprising

[0054] - at least a first fastening system according to the first inventive aspect with a fixed optical element,

[0055] - at least a second fastening system according to the first inventive aspect with a fixed optical element,

[0056] - a first structure with at least three receiving areas configured to receive the fixing portions of a first fastening system and at least three fixing holes,

[0057] - a second structure with at least three receiving areas configured to receive the fixing portions of a second fastening system and at least three fixing holes,

[0058] - at least one set of connecting rods, comprising respective ends, configured to attach the first structure and the second structure, wherein the structures comprise housings configured to receive the ends of the connecting rods, such that the connecting rods extend from the first structure to the second structure, and wherein each end comprises at least one fixing element that can be coupled, configured to fix each end of the rods to respective structures, such that the optical elements of the first fastening system and of the second fastening system are aligned according to the same optical axis.

[0059] Throughout this document, the optical assembly shall be understood to be the sum of two structures attached to one another by at least one set of connecting rods, wherein each structure comprises, fixed thereto, at least one fixing system for fixing the optical element after carrying out the process of assembling said optical element. The structures are fixed such that they are parallel to one another, with a surface of each structure facing the other. In this way, the at least one fastening system of each structure are also aligned and separated at a desired distance with the help of the length of the rods, with the optical elements of the fastening systems of the structures being aligned according to the same optical axis.

[0060] The required number of connecting rods will be that which counteracts any reaction that the optical assembly may experience and does not interfere in the optical path of the optical elements aligned according to the same optical axis and, likewise, does not exceed the volume of the optical assembly. The rods comprise a tubular body extending from a first end to a second end, where the ends are configured to be fixed by means of at least one fixing element to a first structure and a second structure of the optical assembly.

[0061] Optionally, the length of the rods can be regulated. Preferably, the rods comprise at least one regulator at one of the ends.

[0062] In a preferred embodiment, the set of rods used are distributed along the opposing surfaces of the structures, such that a redundant and hyperstatic set is formed. In this way, since the number of rods is redundant, i.e. , by having more rods than necessary, the total capacity or the performance of the optical assembly is increased and the risk of malfunction or non-functioning of the assembly as a result, for example, of the breakage of one of the rods, is reduced. Structures that use more elements than necessary to remain in equilibrium are hyperstatic structures. Hyperstatic is understood as a structure that is in equilibrium, but equations of statics are insufficient to determine all the internal forces or reactions.

[0063] Based on the above, the optical assembly of the invention can be placed in a camera of a satellite and allows obtaining images through the optical elements of the optical assembly when said satellite is in orbit.

[0064] In a third inventive aspect, the invention provides a fastening method for securing an optical element to a fastening system according to the first inventive aspect, which comprises

[0065] - providing at least one fastening system according to the first inventive aspect,

[0066] - providing an optical element,

[0067] - introducing the optical element within the perimeter of the frame in a direction parallel to the frame axis through the side opposite where the protrusions of the frame are located,

[0068] - supporting the optical element on the protrusions on the inside of the frame concentrically,

[0069] - injecting an adhesive into a gap through the at least one hole of the frame,

[0070] - assembling the at least one flexible attachment element on the frame by means of introducing the first tubular area into the through hole of the fixing portion of the frame,

[0071] - placing and fixing the fixing element at a free end of the first tubular area.

[0072] The fastening method for securing an optical element in the fastening system of the invention requires steps necessary for correctly placing the optical element without creating aberrations therein. To that end, once the optical element and at least one fastening system are provided, first, the optical element must be introduced in the frame such that the inner perimeter of the frame and the optical element are concentric and aligned with one another. To that end, the optical element is introduced through the side opposite where the protrusions of the frame are located in a direction parallel to the frame axis and until the optical element abuts with said protrusions of the frame. Preferably, before introducing the optical element in the frame, it is recommendable for the frame to be placed upside down, where the protrusions are located in a lower area such that the upper area of the frame is free of protrusions and it is easier to introduce the optical element.

[0073] In the context of the invention, “upper area” shall be understood as an area above a reference point, in the direction opposite gravity, whereas “lower area” shall be an area zona below that reference point, in the direction of gravity, in both cases with the axis of the frame parallel to the direction of the force of gravity.

[0074] In this same context, the terms “outwardly” and “inwardly” are understood with respect to the axis of the frame.

[0075] Once the frame is placed upside down, the optical element is introduced within the frame in a concentric manner, with the optical element being supported on the protrusions which prevent the optical element from coming out from the lower area of the frame. Next, the adhesive is injected through at least one hole going through the frame, into a region configured to receive the additional fixing element, which is preferably an adhesive. In other words, the adhesive is introduced in the space or gap delimited by the inner perimeter of the frame and the outer perimeter of the optical element in the regions configured to that end. Therefore, the space or gap controls the amount of adhesive to be injected, which is directly related to the drying and hardening time thereof.

[0076] Subsequently, once the adhesive has dried, the frame and the optical element are rotated, with the at least three protrusions being located in an upper area this time. Having performed the rotation, the first tubular area of the flexible attachment element is introduced in the through hole of the fixing portion of the frame through the lower area of the fixing portion. In this way, the first tubular area is free on the fixing portion and the flexible area of the flexible attachment element is located below the fixing portion. Placed and fixed in the free tubular area is the fixing element, for example, a nut element or a nut and washer element which can be threaded onto a threaded surface provided to that end in said free tubular area. In this way, the at least three flexible attachment elements are successfully fixed to the frame, forming the fastening system. Washers are fitting elements which help in positioning the flexible attachment element for the alignment and fitting thereof in a receiving area of the structures of the optical assembly.

[0077] In one embodiment, the fastening method for securing an optical element to a fastening system according to the first inventive aspect, wherein for injecting the adhesive, the method comprises

[0078] - providing an auxiliary assembly element,

[0079] - providing removable gauges,

[0080] - placing the fastening system together with the optical element in the auxiliary assembly element,

[0081] - placing at least two removable gauges on the inside of the frame, such that said gauges delimit a free space between both, and

[0082] - injecting the adhesive into the gap generated between the frame and the optical element and between two gauges through the at least one hole of the frame.

[0083] The auxiliary element comprises a circular body proportional to the fastening system and at least one receiving area in the form of a protuberance projecting towards an upper area according to the axis of the circular body which is the same as that of the frame. Said protuberances generate a housing in which the fastening system is fitted. The receiving area of the auxiliary element comprises a slot where the flexible area of the flexible attachment element and the fixing portion of the frame are housed. Furthermore, an alignment hole of the receiving area has the purpose of receiving the second tubular area of the flexible attachment element for fitting and supporting the frame of the securing element with respect to a horizontal surface of the auxiliary element.

[0084] Once the frame is placed upside down in the auxiliary element, removable gauges are placed on the inside of the frame, such that said gauges will delimit the space in which the fixing adhesive will then be introduced. Said removable gauges are preferably thin sheets of metal, plastic, or composite material, with preestablished dimensions.

[0085] The optical element is then introduced within the frame concentrically as a result of the presence of said gauges, with the optical element being supported on the protrusions which prevent the optical element from coming out from the lower area of the frame. Next, the adhesive is injected through at least one hole going through the frame into a region configured to receive the adhesive, i.e. , into the space or gap delimited, on one hand, between the inner perimeter of the frame and outer perimeter of the optical element, and on the other hand by the presence of two gauges. Therefore, the space or gap controls the amount of adhesive to be injected, which is directly related to the drying and hardening time thereof.

[0086] Subsequently, once the adhesive has dried, the frame, the optical element, and the auxiliary element are rotated, with the at least three protrusions being located in an upper area this time. Having performed the rotation, the removable gauges are removed, and the auxiliary element is removed. The fastening system is fixed to the optical element.

[0087] In a fourth inventive aspect, the invention provides a method for assembling and aligning an optical assembly, which comprises

[0088] - providing a first fastening system according to the first inventive aspect with the fixed optical element,

[0089] - providing a first structure,

[0090] - fixing the first fastening system with the optical element to a first structure by means of introducing at least a second tubular area of the first fastening system in the receiving area configured to that end in the first structure,

[0091] - placing and fixing another fixing element at a free end of the second tubular area,

[0092] - providing a second fastening system according to the first inventive aspect with the fixed optical element,

[0093] - providing a second structure,

[0094] - fixing the second fastening system with the optical element to a second structure by means of introducing at least a second tubular area of the second fastening system in the receiving area configured to that end in the second structure,

[0095] - placing and fixing another fixing element at a free end of the second tubular area,

[0096] - providing a set of connecting rods,

[0097] - providing a plurality of fixing elements, - introducing the ends in the housings of the first structure through an area facing the second structure,

[0098] - fixing the ends by means of the fixing elements through an outer area of the first structure,

[0099] - introducing the ends of the rods in the housings of the second structure through an area facing the first structure,

[0100] - fixing the ends by means of the fixing elements through an outer area of the second structure,

[0101] - aligning the first fastening system and the second fastening system,

[0102] - measuring the alignment and the optical quality of the optical assembly once assembled to check that no aberrations have occurred during assembly.

[0103] The assembly and alignment of the optical assembly is necessary for installation thereof in the camera of the satellite. It is necessary that the optical element of the first structure and the optical element of the second structure be aligned according to one and the same optical axis before placement thereof in the camera. The alignment of the optical elements is performed by means of washers in the flexible attachment elements, whereas the alignment of the first and second structures is performed by means of the placement and fitting of rods on the first and second structures. To that end, first, it is necessary to provide a first fastening system fixed to a first structure and a second fastening system fixed to a second structure. Furthermore, it is also necessary to provide a set of connecting rods and a plurality of fixing elements whereby the optical assembly can then be formed and optimally aligned for the camera of the satellite.

[0104] In a preferred embodiment, the alignment of the optical assembly is performed by means of the set of connecting rods. In that sense, upon placing and aligning the first and second structures at the desired distance established by the rods, the structures are aligned and parallel to one another at the desired distance. In turn, for the placement of the structures, the ends of the rods must be introduced through the fixing holes of the first and second structures and then fixed by means of the fixing elements to the ends of the rods, with the fixing elements being located on both surfaces of the structures.

[0105] In that sense, first, a first end of the rod is introduced through at least one fixing hole of the first structure, specifically on a lower surface of the first structure which is facing an upper surface of the second structure. Once introduced, the first end of the rod is fixed by means of at least two fixing elements on an upper surface and a lower surface of the first structure. This step is repeated with as many rods as desired to be placed for the alignment of the optical assembly. The fixing elements can be, for example, a nut element or a nut and washer element which can be threaded onto a threaded surface provided to that end at the end of the rod.

[0106] The free ends or second ends of the rods placed in the first structure are then fixed by introducing the seconds ends in the fixing holes of the second structure on the surface facing the first structure. Lastly, the seconds ends of the rods are fixed by means of the fixing elements of the rods on both upper and lower surfaces of the second structure, with the structures being located at the desired distance.

[0107] Having placed the structures of the optical assembly, the optical elements of the first fastening system and the second fastening system are aligned according to the same optical axis. Finally, once the optical assembly is aligned, alignment and optical quality measurements are performed to verify that no aberrations have occurred during assembly in the assembled optical assembly.

[0108] The alignment of the optical element fastening systems and the structures of the optical assembly involve several elements, i.e. , the flexible attachment elements for stabilizing the securing element with the optical element in the receiving area of the structures, and at least one calibrated fitting washer placed in the flexible attachment element in the attachment thereof with the frame, specifically located between the fixing portion of the frame and the fixing element of the first tubular area of the flexible attachment element. Lastly, rods for the correct alignment and arrangement of the structures are also involved.

[0109] In a fifth inventive aspect, the invention provides a camera comprising at least one optical assembly according to the second inventive aspect and any of the embodiments thereof.

[0110] By means of the systems and assemblies of the invention, a camera configured to be mounted in a satellite by means of a suitable fixing is achieved, without affecting the integrity of the lens, without generating aberrations when capturing images, and allowing the prevention of possible vibrations, etc., in the optical element.

[0111] All the features and / or steps of methods described in this specification (including the claims, description, and drawings) can be combined in any combination, with the exception of the combinations of such mutually exclusive features.

[0112] DESCRIPTION OF THE DRAWINGS

[0113] These and other features and advantages of the invention will become more apparent from the following detailed description of at least one preferred embodiment, given solely by way of illustrative and non-limiting example in reference to the attached figures.

[0114] Figure 1 shows a perspective view of the fastening system of the invention and the optical element to be secured.

[0115] Figure 2 illustrates a bottom perspective view of the fastening system of the invention and the optical element to be secured.

[0116] Figure 3A shows a perspective view of the frame of the fastening system of the invention.

[0117] Figure 3B shows a perspective view of the flexible attachment element of the fastening system of the invention.

[0118] Figure 4A shows a perspective view of the fastening system and the optical element with the adhesive and the gauges in an exploded view.

[0119] Figure 4B shows a perspective view of the fastening system and the optical element with the gauges in an exploded view.

[0120] Figure 5 shows a perspective view of an auxiliary element. Figure 6 shows a perspective view of the fastening system on the auxiliary element.

[0121] Figure 7 illustrates a perspective view of the optical assembly of the invention.

[0122] Figure 8 shows a plan view of a structure of the aligned optical assembly.

[0123] Figure 9 illustrates an exploded perspective view of the aligned optical assembly and the fastening system.

[0124] DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

[0125] Fastening system

[0126] Figures 1 to 4B show a fastening system (1 , 100) for securing at least one optical element (2, 200), with an outer perimeter of length L2, to a first or second structure (10, 11 ). The fastening system (1 , 100) comprises a frame (3) and at least three flexible attachment elements (5).

[0127] In turn, the frame (3) comprises an inner perimeter of length L3, with L3 being greater than the outer perimeter L2 of the optical element. Both perimeters L2 and L3 comprise the same shape and are concentric, given that the frame (3) is configured to be fixed around the outer perimeter L2 of the optical element (2, 200). Furthermore, the frame (3) comprises a frame axis (3d), an inner surface (3b), and an outer surface (3a) as shown in Figure 3A. The outer surface (3a) of the frame (3) comprises at least three fixing portions (4) where there are coupled the at least three flexible attachment elements (5) which allow attaching the fastening system (1 , 100) for securing the optical element (2, 200) to the first or second structure (10, 11 ) as shown below.

[0128] The at least three fixing portions (4) are located on the outer surface (3a) of the frame and perpendicular to the frame axis (3d) towards the outside of the frame (3) as can be seen in Figures 1 and 2. Preferably, said at least three fixing portions (4) are located in an upper area of the outer surface (3a) of the frame. Additionally, the fixing portions (4) comprise a through hole (4a) in a direction parallel to the axis of the frame through which the flexible attachment elements (5) are introduced.

[0129] The frame (3) also comprises at least one hole (3c) going through same from an outer surface (3a) to an inner surface (3b) and at least three protrusions (6), each protrusion (6) projecting in a direction perpendicular to the frame axis (3d) from the outer surface (3a) to the axis of the frame (3d) and at least one of the protrusions is arranged above a hole (3c), as shown in Figures 1 to 4B.

[0130] Specifically, as can be seen in Figures 1 , 2, and 3B, each flexible attachment element (5) comprises a first tubular area (5a), a second tubular area (5c), a flexible region (5b), and at least one fixing element (5d) in each flexible attachment element (5). The first tubular area (5a) is configured to be introduced through the through hole (4a) of the fixing portion (4) of the frame (3) and to be fixed by means of the fixing element (5d) which is fixed on the fixing portion (4) in the first tubular area (5a). In this way, as can be seen in the figures, the fixing portion (4) is fixed between a fixing element (5d) and the flexible region (5b). The second tubular area (5c) is configured to be introduced in a receiving area configured to that end in the first or second structure (10, 11 ) and is fixed by means of another fixing element in the lower area of the optical assembly (40) as shown in Figures 8 to 9. As is also shown in Figures 1 and 2, the fixing elements (5d) are, for example, a nut or a nut and a washer which can be threaded onto a threaded surface provided to that end in the free tubular areas of the flexible attachment element (5).

[0131] The inner surface (3b) of the frame (3) comprises at least three regions (3e) configured to fix the optical element (2, 200) to the frame (3). These regions (3e) are located in an inner area coinciding with the at least three protrusions (6) and the hole (3c). Preferably, the regions (3e) are configured to receive a fixing adhesive (8) through the hole (3c), the adhesive (8) preferably being a bicomponent adhesive (8).

[0132] Optionally, as shown in Figures 1 to 3A, the three regions (3e) configured to receive the adhesive (8) coincide with recessed areas (3f) of the frame (3). Stops, not shown in the figures, are placed in said recessed areas (3f) of the frame (3) to control the amount of adhesive (8) to be received in each of said regions (3e). In a preferred embodiment, the fastening system (1 , 100) is the one shown in the figures, whereby it comprises three flexible attachment elements (5), and therefore three fixing portions (4). Likewise, it has three protrusions (6) above three holes (3c) facing the fixing portions (4), and each protrusion (6) is located substantially in the center of the space between every two fixing portions (4). Furthermore, it can be seen that the optical element (2, 200), and therefore the frame (3), have a circular configuration and an annular configuration, respectively, and the outer surface (3a) of the frame (3) is flat and parallel to the frame axis (3d).

[0133] Particularly, the frame (3) is made of a material such as metal, composite, or plastic.

[0134] Auxiliary element for fixing the optical element in the fixing system

[0135] Figures 5 and 6 show an auxiliary element (15) used to facilitate the correct positioning and adhesion of the optical element (2, 200) in the fastening system (1 , 100).

[0136] The auxiliary element (15) comprises a circular body, at least one receiving area (15a) which generates a housing with a horizontal surface (15e) comprising at least one alignment hole (15b). Specifically, the receiving area (15a) is a protuberance projecting towards an upper area according to the axis of the frame (3d) comprising a slot (15c). The purpose of the alignment hole (15b) is to receive the second tubular area (5b) of the flexible attachment element (5) and to fix it with the fixing element (5d) in the lower part of the auxiliary element (15) as can be seen in Figure 6.

[0137] The slot (15c) houses the flexible area (5c) of the flexible attachment element (5) and the fixing portion (4) of the frame (3) as shown in Figure 6.

[0138] This auxiliary element (15) allows facilitating assembly, specifically the optimal adhesion of the optical element (2, 200) to the fastening system (1 , 100), as will be explained below. Structure for fixing the optical element fixing system

[0139] Figures 8 to 10 show a first structure (10) and a second structure (11 ) to which the fastening system (1 , 100) of the invention, shown in Figures 1 and 4B, is coupled to form an optical assembly (40) of the invention shown in Figure 8.

[0140] Given that the fastening system (1 , 100) is preferably circular, the first or second structure (10, 11 ) comprise an also circular cavity, for the purpose of and with a shape for housing the at least one fastening system (1 , 100), with its center in the same axis of the frame (3d) once the fastening system (1 , 100) is coupled, as shown in Figures 8 and 10.

[0141] The first and second structures (10, 11 ) comprise at least one receiving area (10a, 11 a) on an upper surface to receive at least one fixing portion (4) and at least one flexible attachment element (5) of the frame (3) and at least one alignment hole (10b, 11 b). Specifically, the circular cavity and the receiving area (10a, 11 a) are a recess in the structure (10, 11 ) for supporting the fastening system (1 , 100) as shown in Figures 9 and 10. Each receiving area (10a, 11a) comprises a fixing hole (10b, 11 b) on the recess surface for the purpose of receiving the second tubular area (5b) of the flexible attachment element (5) and fixing it with the fixing element (5d) in the lower part of the structure (10, 11 ) as can be seen in Figures 8 and 10.

[0142] Optical assembly with a structure for the optical element fastening system

[0143] In an embodiment of the aligned optical assembly (40), as shown in Figure 8, it can be seen that the optical assembly (40) comprises at least a first fastening system (1 ) with an optical element (1 ) fixed in a first structure (10), at least a second fastening system (100) with an optical element (100) fixed in a second structure (11 ) and a set of connecting rods (12).

[0144] The connecting rods (12) comprise respective ends (12a, 12b) provided with attachment sleeves (12d), configured to attach and fix the first structure (10) together with at least a first fastening system (1 ) to the second structure (11 ) together with at least a second fastening system (100), at a desired distance and alignment established by means of the rods (12). In one embodiment, the length of the rods (12) can be regulated by means of a regulator, such that the alignment and arrangement of the structures (10, 11 ) is facilitated.

[0145] As shown in Figures 8 and 9, the first and second structures (10, 11 ) comprises fixing holes (10b, 11 b) configured to receive the ends (12a, 12b) of the connecting rods (12), such that the connecting rods (12) extend from the first structure (10) to the second structure (11 ). For the fixing of the rods (12) to the structure (10, 11 ), specifically for the fixing of the ends (12a, 12b), the rods (12) comprises at least one fixing element (12c) that can be coupled, configured to fix each end (12a, 12b) to said structures (10, 11 ) such that said structures (10, 11 ) are aligned and separated by a distance established by said rods (12). Said fixing elements (12c) are, for example, a nut or a nut and washer which can be threaded on a threaded surface provided to that end at the ends (12a, 12b) of the connecting rods (12).

[0146] Fastening method for an optical element

[0147] The fastening method for securing an optical element (2, 200) to a fastening system (1 , 100) comprises the steps described below.

[0148] First, a fastening system (1 , 100) and an optical element (2, 200) such as those of Figures 1 to 4B must be provided. Next, the optical element (2, 200) must be introduced within the perimeter L3 of the frame (3) in a direction parallel to the frame axis (3d) and through the side opposite where the protrusions (6) of the frame (3) are located, for which the frame (3) must previously be rotated 180°. In turn, gauges (9) are introduced between the frame (3) and the optical element (2, 200), generating a gap (7) between every two gauges (9). In this way, the optical element (2) is supported on the protrusions (6) on the inside of the frame (3) and as a result of the gauges (9), the optical element (2, 200) is located concentrically to enable injecting the adhesive (8) through the at least one hole (3c) of the frame (3) into said gap (7) generated between the frame (3) and the optical element (2) and between every two gauges (9) as can be seen in Figures 4A and 4B.

[0149] In the embodiment in which the frame (3) comprises recessed areas (3f), stops (not shown in the figures) are placed in said recessed areas (3f) to control the amount of adhesive (8) to be received in each of said regions (3e). In this way, said stops prevent the adhesive (8) from leaking out from the regions (3e) configured to receive the adhesive (8) due to gravity.

[0150] Next, the at least one flexible attachment element (5) is assembled in the frame (3) by means of introducing the first tubular area (5a) into the through hole (4a) of the fixing portion (4) of the frame (3) for placing and fixing the fixing element (5d) at a free end of the first tubular area (5a), with the fixing element (5d) being located on the fixing portion (4) as shown in Figure 1 .

[0151] Finally, it is possible to perform, in a complementary manner, the method of assembling the optical element (2, 200) in a fastening system by means of using the auxiliary element (15).

[0152] To that end, the frame (3) is first introduced in the auxiliary element (15) housing the fixing portions (4) of the frame (3) in the receiving areas (15a) as shown in Figure 6.

[0153] Next, the frame (3) is fixed by means of the flexible attachment elements (5) to the auxiliary element (15), introducing the first tubular area (5a) in the fixing portion (4) of the frame (3) through the lower part of the frame (3) and the second tubular area (5c) in the alignment hole (15b), with the flexible area (5b) of the flexible attachment element (5) being located in the receiving area (15a) of the auxiliary element (15).

[0154] Once the fastening system (1 , 100) is fixed to the auxiliary element (15), the optical element (2, 200) is placed by means of introducing the optical element (2, 200) within the perimeter L3 of the frame (3) in a direction parallel to the frame axis (3d) and through the side opposite where the protrusions (6) of the frame (3) are located. In turn, gauges (9) are introduced between the frame (3) and the optical element (2, 200), which gauges can be introduced alternatively before introducing the optical element (2, 200) in the fastening system (1 , 100).

[0155] In this way, the optical element (2) is supported on the protrusions (6) on the inside of the frame (3) and as a result of the gauges (9), the optical element (2, 200) is housed in a concentric manner to enable injecting the adhesive (8) through the at least one hole (3c) of the frame (3) into a gap (7) generated between the frame (3) and the optical element (2) and between every two gauges

[0156] (9) as can be seen in Figures 4A and 4B.

[0157] Method for assembling and aligning an optical assembly

[0158] The method for assembling and aligning an optical assembly (40) for the subsequent placement of said optical assembly (40) in a satellite comprises providing at least a first fastening system (1 ) with an optical element (2), at least a second fastening system (100) with an optical element (200), at least a first structure (10), at least a second structure (11 ), a set of connecting rods (12), and a plurality of fixing elements (12c).

[0159] First, in order to fix the fastening system (1 , 100) to the first and second structures (10, 11 ), the second tubular area (5c) must be introduced in the receiving area (10a, 11 a) configured to that end in the first or second structure (10, 11 ) and another fixing element (5d) must be placed and fixed at a free end of the second tubular area (5c) through a lower area of the structure (10, 11 ).

[0160] Next, in order to assemble the optical assembly (40), the connecting rods (12) of the set of connecting rods (12) are introduced one by one in the first structure

[0161] (10). Specifically, the ends (12a) are introduced in the housings (10c) of the first structure (10) through an area facing the second structure (11 ). As can be seen in Figures 8 to 10, the structures (10, 11 ) are placed in parallel, with one face of each structure (10, 11 ) facing one another and located at a desired distance, established with the help of the length of the set of connecting rods (12).

[0162] Once the ends (12a) of the rods (12) are introduced in the first structure, the ends (12a) are fixed by means of the fixing elements (12c) placed through an outer area and an inner area of the first structure (10), with the outer area being understood as the face opposite the face facing the second structure (11 ).

[0163] Having fixed the ends (12a) to the first structure, the same operation is repeated with the ends (12b) in the second structure (11 ). In other words, the ends (12b) are introduced in the housings (11 c) of the second structure (11 ) through an area facing the first structure (10), and the ends (12a) are then fixed by means of the fixing elements (12c) through both outer and inner areas of the second structure (11 ).

[0164] Once the optical assembly (40) is assembled, the first and second structures (10, 11 ) of the fastening systems (1 , 100) are aligned and to that end the flexible attachment elements (5) and the rods (12) are fitted together. The flexible attachment elements (5) are used for the placement and correct positioning of the fastening system (1 , 100) in the receiving area (10a, 11a) of the structures (10, 11 ), whereas the rods (12) are used to adjust the parallelism and the distance between the structures (10, 11 ) of the optical assembly (40).

[0165] Lastly, once assembled, the alignment and the optical quality of the optical assembly (40) is measured to check that no aberrations have occurred in the optical elements (2, 200) during assembly.

[0166] Camera

[0167] In one embodiment not shown in the figures, at least one optical assembly (40) is part of a camera that can be mounted in a microsatellite and / or satellite.

Claims

CLAIMS1. Fastening system (1 , 100) for securing at least one optical element (2, 200) with an outer perimeter of length L2 to a first or second structure (10, 11 ) of an optical assembly (40), the fastening system (1 , 100) comprising- a frame (3) with an inner perimeter of length L3, with L3 > L2 or L3 being slightly greater than L2, said frame being concentric and configured to be fixed around the outer perimeter of the optical element (2, 200), comprising a frame axis (3d), an inner surface (3b) in turn comprising at least three regions (3e) configured to fix the optical element (2, 200) and an outer surface (3a) comprising at least three fixing portions (4), and- at least three flexible attachment elements (5) for attachment with the first structure or second structure (10, 11 ) coupled respectively in each fixing portion (4), wherein the at least three fixing portions (4) are located on the outer surface (3a), are perpendicular to the frame axis (3d), and have a through hole (4a), and the frame (3) comprises- at least three holes (3c) perpendicular to the frame axis (3d), and- at least three protrusions (6), each protrusion (6) projecting in a direction perpendicular to the frame axis (3d) from the outer surface (3a) to the inner surface (3b) of the frame (3) and arranged above the hole (3c) in the direction of the frame axis (3d).

2. Fastening system (1 , 100) according to claim 1 , wherein the at least three regions (3e) are configured to receive an adhesive (8) for fixing the optical element (2, 200).

3. Fastening system (1 , 100) according to claim 2, wherein the adhesive (8) is a bicomponent adhesive.

4. Fastening system (1 , 100) according to claim 1 , wherein the frame (3) has an annular configuration, and the inner surface (3b) of the frame (3) is flat and parallel to the frame axis (3d).

5. Fastening system (1 , 100) according to any of the preceding claims, whereineach flexible attachment element (5) comprises- a first tubular area (5a) configured to be introduced through the through hole (4a) of each fixing portion (4) of the frame (3),- a second tubular area (5c) configured to be introduced in a receiving area configured to that end in the first or second structure (10, 11 ) of the optical assembly, and- a flexible region (5b) arranged between the first and second tubular areas (5a, 5c),- at least one fixing element (5d) that can be coupled at each of the ends of the first and second tubular areas (5a, 5c) configured to fix the first tubular area (5a) and the fixing portion (4) and the second tubular area (5c) and the first or second structure (10, 11 ).

6. Fastening system (1 , 100) according to any of the preceding claims, wherein the frame (3) is made of a material selected from metal, composite, and plastic.

7. Optical assembly (40) comprising- at least a first fastening system (1 ) according to any of claims 1 to 6 with a fixed optical element (2, 200),- at least a second fastening system (100) according to any of claims 1 to 6 with a fixed optical element (2, 200),- a first structure (10) with at least three receiving areas (10a) configured to receive the fixing portions (4) of the first fastening system (1 ) and at least three fixing holes (10b),- a second structure (11 ) with at least three receiving areas (11a) configured to receive the fixing portions (4) of the second fastening system (100) and at least three fixing holes (11 b),- at least one set of connecting rods (12), comprising respective ends (12a, 12b), configured to attach the first structure (10) and the second structure (11 ), wherein the structures (10, 11 ) comprise housings (10c, 11 c) configured to receive the ends (12a, 12b) of the connecting rods (12), such that the connecting rods (12) extend from the first structure (10) to the second structure (11 ), and wherein each end (12a, 12b) comprises at least one fixing element (12c) that can be coupled, configured to fix each end of the rods (12a, 12b) to respective structures (10, 11 ), such that the optical elements (2, 200) of the first fastening system (1 )and of the second fastening system (100) are aligned according to the same optical axis.

8. Optical assembly (40) according to claim 7, wherein the length of the rods (12) can be regulated.

9. Fastening method for securing an optical element (2, 200) to a fastening system (1 , 100) according to any of claims 1 to 6, which comprises- providing at least one fastening system (1 , 100) according to any of claims 1 to 6,- providing an optical element (2, 200),- introducing the optical element (2, 200) within the perimeter of the frame (3) in a direction parallel to the frame axis (3d) through the side opposite to where the protrusions (6) of the frame (3) are located,- supporting the optical element (2, 200) on the protrusions (6) on the inside of the frame (3) concentrically,- injecting an adhesive (8) into a gap (7) generated between the frame (3) and the optical element (2, 200), through the at least one hole (3c) of the frame (3),- assembling the at least one flexible attachment element (5) on the frame (3) by means of introducing the first tubular area (5a) into the through hole (4a) of the fixing portion (4) of the frame (3),- placing and fixing the fixing element (5d) at a free end of the first tubular area (5a).

10. Fastening method for securing an optical element (2, 200) to a fastening system (1 , 100) according to any of claims 1 to 6, wherein for injecting the adhesive, the method comprises- providing an auxiliary assembly element (15),- providing removable gauges (9)- placing the fastening system (1 , 100) together with the optical element (2, 200) in the auxiliary assembly element (15),- placing at least two removable gauges (9) on the inside of the frame (3), such that said gauges delimit a free space between both, andinjecting the adhesive (8) into the gap (7) generated between the frame and the optical element and between two gauges through the at least one hole (3c) of the frame (3).

11. Method for assembling and aligning an optical assembly (40), which comprises- providing at least a first fastening system (1 ) according to any of claims 1 to 6, with a fixed optical element (2, 200),- providing a first structure (10),- fixing the first fastening system (1 ) with the optical element (2) to the first structure (10) by means of introducing at least a second tubular area (5c) of the first fastening system (1 ) in the receiving area (10a) configured to that end in the first structure (10),- placing and fixing another fixing element (5d) at a free end of the second tubular area (5c),- providing at least a second fastening system (100) according to any of claims 1 to 6, with a fixed optical element (2, 200),- providing a second structure (11 ),- fixing the second fastening system (100) with the optical element (200) to the second structure (11 ) by means of introducing at least a second tubular area (5c) of the second fastening system (100) in the receiving area (11 a) configured to that end in the second structure (11 ),- placing and fixing another fixing element (5d) at a free end of the second tubular area (5c),- providing a set of connecting rods (12), each attachment rod (12) comprising respective ends (12a, 12b),- providing a plurality of fixing elements (12c),- introducing the ends (12a) in the housings (10c) of the first structure (10) through an area facing the second structure (11 ),- fixing the ends (12a) by means of the fixing elements (12c) through an outer area of the first structure (10),- introducing the ends (12b) in the housings (11 c) of the second structure (11 ) through an area facing the first structure (10),- fixing the ends (12b) by means of the fixing elements (12c) through an outer area of the second structure (11 ),- aligning the first and second structures (10, 11 ),- measuring the alignment and the optical quality of the optical assembly (40) once assembled to check that no aberrations have occurred during assembly.

12. Camera for microsatellites and / or satellites comprising at least one optical assembly (40) according to any of claims 7 and 8.

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