A lens and a camera for optical communication

Abstract

The present invention relates to the field of optical communication technologies, and provides a lens and a camera for optical communication. The lens includes: a lens frame with the light incident end as the front end; a first lens which is a positive lens and is disposed at the front end of the lens frame; a mounting portion which is disposed within the lens frame and is located behind the first lens; and a filter which is detachably mounted at the mounting portion. The present invention can conveniently change the optimal working wavelength of the lens, and there is no need to use lenses made of multiple different materials to achieve achromatism. It is convenient to manufacture and use, and has a low manufacturing cost.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technologies, and particularly to a lens and a camera for optical communication. Background Art

[0002] In the field of free-space optical communication, especially in fields such as space-ground communication, a ground station is generally built on the ground as a receiving end. In a communication system with an independent beacon, the ground station uses a camera to receive beacon light for tracking. There are various choices for the current beacon light wavelengths, such as 532nm, 671nm, 808nm, 830nm, 850nm, etc.

[0003] For beacon lights of different wavelengths, the camera lens of the ground station also needs to be replaced accordingly to achieve the best capture and tracking effects. For example, a group of beacon lights are the uplink 671nm beacon light and the downlink 532nm beacon light, that is, the spaceborne terminal sends down the 532nm beacon light and receives the 671nm beacon light, and the ground station emits the 671nm beacon light and uses the camera to receive the 532nm beacon light for capture and tracking work. At this time, the working wavelength of the ground station camera is 532nm, and the lens needs to achieve the best capture and tracking effects for this wavelength, that is, the best working wavelength of the lens is 532nm. However, the ground station has a high cost and great difficulty. Currently, the market requires the ground station to be able to capture and establish a link with a variety of different communication terminals, that is, it needs to be able to respond to downlink beacons such as 532nm, 671nm, 808nm, 830nm, 850nm, etc. Correspondingly, the best working wavelength of the lens should be able to switch between values such as 532nm, 671nm, 808nm, 830nm, 850nm, etc. to achieve the best communication effects. The above method of replacing the camera lens has many limitations and inconveniences in the actual implementation process.

[0004] Currently, when designing an achromatic lens, generally different glass combinations with different refractive indices and dispersive powers are selected to compensate for chromatic aberration. However, the glass materials available for aerospace devices are limited. To ensure reliability, the design results are generally required to be close to the diffraction limit. In addition, it is also required to minimize the number of lenses used and perform achromatic design in a two-piece or three-piece structure. Especially under such many restrictions, it is extremely difficult to meet the working wavelength span from 532nm to 850nm in multiple bands and reach the diffraction limit at the corresponding working wavelengths. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a lens and a camera for optical communication, which can conveniently change the best working wavelength of the lens, and there is no need to use lenses of multiple different materials to achieve achromatism. Both manufacturing and use are relatively convenient and the manufacturing cost is low.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A lens, comprising: a lens frame with the light incident end as the front end; a first lens which is a positive lens and is arranged at the front end of the lens frame; a mounting portion which is arranged inside the lens frame and behind the first lens; and a filter which is detachably mounted at the mounting portion.

[0008] By mounting filters with different thicknesses at the mounting portion, the lens can achieve different optimal working wavelengths.

[0009] The lens further comprises: a second lens which is a negative lens and is arranged behind the mounting portion.

[0010] The lens further comprises: a second lens which is a negative lens and is arranged between the first lens and the mounting portion.

[0011] The first lens comprises a first lens element and a second lens element. The front surface of the first lens element is convex, the rear surface of the first lens element is flat, the front surface of the second lens element is convex, and the rear surface of the second lens element is concave.

[0012] The second lens comprises a third lens element. Both the front surface and the rear surface of the third lens element are concave.

[0013] Both the front surface and the rear surface of the filter are flat.

[0014] The first lens, the second lens and the filter are made of the same material.

[0015] A camera for optical communication, comprising the above-mentioned lens.

[0016] Advantages of the present invention:

[0017] By providing a mounting portion facilitating the disassembly of the filter to replace filters with different thicknesses, the optimal working wavelength of the lens can be conveniently changed, and there is no need to use lenses made of multiple different materials to achieve achromatism. It is convenient to manufacture and use and has a low manufacturing cost. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of the lens according to an embodiment of the present invention;

[0019] Figure 2 It is a schematic structural diagram of the lens according to an embodiment of the present invention;

[0020] Figure 3 It is a schematic structural diagram of the lens elements of the lens according to a specific embodiment of the present invention.

[0021] Reference numerals:

[0022] Lens frame 10, first lens 20, mounting portion 30, filter 40, second lens 50;

[0023] First lens element 21, second lens element 22, third lens element 51. Detailed implementation manners

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] As Figure 1 shown, the lens in the embodiment of the present invention includes a lens frame 10, a first lens 20, a mounting portion 30, and a filter 40. The lens frame 10 has the light incident end as the front end; the first lens 20 is a positive lens, and the first lens 20 is disposed at the front end of the lens frame 10; the mounting portion 30 is disposed inside the lens frame 10 and behind the first lens 20; the filter 40 is detachably mounted at the mounting portion 30.

[0026] In an embodiment of the present invention, the mounting portion 30 at least includes a mounting hole opened on the side wall of the lens frame 10, for example, a rectangular mounting hole with a length greater than the diameter of the filter 40 and a width greater than the thickness of the filter 40, so as to install and remove the filter 40 by inserting and pulling out. In another embodiment of the present invention, the mounting portion 30 can be detachably connected to the lens frame 10, the filter 40 is located inside the mounting portion, and the detachable property of the filter 40 is realized through the detachable property of the mounting portion 30.

[0027] Based on the structure of the above lens, by installing filters 40 with different thicknesses at the mounting portion 30, the lens can achieve different optimal working wavelengths. When receiving light with the optimal working wavelength, the imaging effect of the lens is the best, and the capture and tracking effect is the best.

[0028] Furthermore, as Figure 2 shown, the lens in the embodiment of the present invention may further include a second lens 50. The second lens 50 is a negative lens. The second lens 50 can be disposed behind the mounting portion 30, or the second lens 50 can be disposed between the first lens 20 and in front of the mounting portion 30. Figure 2 Taking the case where the second lens 50 is disposed behind the mounting portion 30 as an example.

[0029] In a preferred embodiment of the present invention, the second lens 50 is disposed behind the mounting portion 30. Compared with the case where it is disposed behind the first lens 20 and in front of the mounting portion 30, the thickness of the filter 40 used to achieve the same optimal operating wavelength is smaller.

[0030] Since the embodiment of the present invention changes the optimal operating wavelength of the lens by changing the thickness of the filter 40, there is no need to use lenses made of multiple different materials to achieve achromatism. In an embodiment of the present invention, the first lens 20, the second lens 50, and the filter 40 can be made of the same material, for example, quartz material can be used for all of them.

[0031] In a specific embodiment of the present invention, as Figure 3 shown, the first lens 20 includes a first lens element 21 and a second lens element 22. The front surface of the first lens element 21 is convex, the rear surface of the first lens element 21 is flat, the front surface of the second lens element 22 is convex, and the rear surface of the second lens element 22 is concave. The second lens 50 includes a third lens element 51, and both the front surface and the rear surface of the third lens element 51 are concave. Both the front surface and the rear surface of the filter 40 are flat. The parallelism of the two surfaces of the filter is better than 3″, and the surface form RMS (root mean square) is better than 1 / 20λ@632.8nm. The optical element parameters of this lens are shown in Table 1.

[0032] Table 1

[0033]

[0034]

[0035] The thicknesses in Table 1 represent the thicknesses of the respective components / spacings at the optical axis. The air gap d is the gap between the third lens element and the imaging focal plane. It should be further understood that the radius of curvature of the front surface of each air gap is the radius of curvature of the rear surface of the component in front of it.

[0036] For Figure 3 the lens shown, the relationship between its optimal operating wavelength and the filter thickness is shown in Table 2.

[0037] Table 2

[0038] Optimal working wavelength / μm 0.532 0.671 0.808 0.830 0.850 Filter thickness / mm 3.500 2.500 1.900 1.820 1.750

[0039] For example, in Figure 3 where the distance between the first lens 20 and the second lens 50 remains unchanged (24.015mm), if the lens is to receive beacon light with a wavelength of 532nm, a filter with a thickness of 3.5mm can be inserted. If the lens is to receive beacon light with a wavelength of 671nm instead, a filter with a thickness of 2.5mm can be replaced.

[0040] The lens according to an embodiment of the present invention can conveniently change the optimal working wavelength of the lens by providing an installation part that facilitates the disassembly of the filter to replace filters of different thicknesses, and there is no need to use lenses made of multiple different materials to achieve achromatism. It is convenient to manufacture and use and has a low manufacturing cost.

[0041] Based on the lens of the above embodiment, the present invention further provides a camera for optical communication.

[0042] The camera for optical communication according to an embodiment of the present invention includes the lens of any one of the above embodiments of the present invention. The specific implementation manner can refer to the above embodiments and will not be elaborated here.

[0043] The camera for optical communication according to an embodiment of the present invention can conveniently change the optimal working wavelength of the lens, and there is no need to use lenses made of multiple different materials to achieve achromatism. It is convenient to manufacture and use and has a low manufacturing cost.

[0044] In the description of the present invention, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. The meaning of "a plurality" is two or more unless otherwise specifically defined.

[0045] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected to", "fixed" and other terms should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0047] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0048] Any process or method description represented in a flowchart or described in other ways herein can be understood to represent a module, segment, or part of code including one or more executable instructions for implementing a specific logical function or process. The scope of the preferred embodiments of the present invention includes additional implementations, where the functions can be executed in a manner that may not be shown or discussed in the order presented, including in a substantially simultaneous manner according to the functions involved or in a reverse order, which should be understood by those skilled in the art to which the embodiments of the present invention pertain.

[0049] The logic and / or steps represented in a flowchart or described in other ways herein, for example, can be considered as a sequenced list of executable instructions for implementing a logical function, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in conjunction with such instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium include the following: an electrical connection portion having one or more wirings (electronic device), a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other appropriate processing as necessary, and then stored in a computer memory.

[0050] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one of the following techniques known in the art or a combination thereof can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0051] Those of ordinary skill in the art can understand that all or part of the steps carried by the method of the above embodiments can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0052] In addition, each functional unit in various embodiments of the present invention can be integrated into a processing module, or each unit can exist physically alone, or two or more units can be integrated into one module. The above integrated module can be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0053] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A lens, characterized in that, for a camera which is used for optical communication, the lens includes a lens frame, a mounting portion, a filter and a lens assembly, and the lens assembly is composed of a first lens group and a second lens group, wherein, the lens frame has the light incident end as the front end; the first lens group is a positive lens, the first lens group is arranged at the front end of the lens frame, the first lens group is composed of a first lens and a second lens, the front surface of the first lens is convex, the rear surface of the first lens is flat, the front surface of the second lens is convex, and the rear surface of the second lens is concave; the mounting portion is arranged inside the lens frame and behind the first lens group; the filter is detachably mounted at the mounting portion, and by mounting filters with different thicknesses at the mounting portion, the lens can achieve different optimal working wavelengths; the second lens group is a negative lens, the second lens group is arranged behind the mounting portion, or the second lens group is arranged between the first lens group and the mounting portion, the second lens group is a third lens, and both the front surface and the rear surface of the third lens are concave, wherein, the first lens group, the second lens group and the filter are made of the same material.

2. The lens according to claim 1, characterized in that, both the front surface and the rear surface of the filter are flat.

3. A camera for optical communication, characterized in that, comprising the lens according to claim 1 or 2.

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