A large-aperture reflective zoom and laser communication integrated camera

Abstract

A large-aperture reflective zoom and laser communication integrated camera is disclosed, relating to the fields of optoelectronic imaging and laser communication technology. It addresses the technological gap where liquid zoom lenses cannot be applied to large-aperture RC systems, and the problem of relying on additional components for integrated visible light imaging and laser communication, making it difficult to balance lightweight design and high performance. The camera consists only of a primary mirror, a liquid zoom lens array, a grating film, a visible light detector, and an infrared detector. The front of the liquid zoom lens integrates a multi-layer liquid zoom lens array, with each layer having a different focal length. Independent drive circuits electrically control and adjust each lens layer to eliminate aberrations and adjust the focal length for optical systems of different apertures. The grating film on the back exhibits high reflectivity to visible light and high transmittance to 1550nm laser light, enabling visible light to form an RC structure imaging optical path, while the laser light is transmitted to complete communication. This invention can be widely applied in aerospace, aviation, and ground observation scenarios.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic imaging and laser communication technology, specifically to a large-aperture reflective zoom and laser communication integrated camera, which is particularly suitable for aerospace, aviation and ground observation scenarios that require both high-resolution visible light imaging and long-distance laser communication capabilities. Background Technology

[0002] Liquid zoom lenses, with their advantages of no mechanical wear, fast response, and continuously adjustable focal length, have found some application in small-aperture refractive optical systems, such as security monitoring lenses where multi-fold continuous zoom has been achieved. However, their application in large-aperture RC reflection systems remains a technological gap. Focusing in large-aperture RC reflection systems generally relies on the displacement of precision mechanical components. The introduction of moving components not only increases the size and weight of the system but also reduces its operational reliability. In contrast, liquid zoom lenses have no moving components; they achieve flexible focal length adjustment by adjusting the wettability of the liquid through the control of an applied voltage. However, the aperture of existing liquid zoom lenses is mostly limited to the millimeter level. Even though some manufacturers, such as Optotune, have launched large-aperture products with a maximum aperture exceeding 30mm, they still cannot meet the aberration correction requirements of large-aperture systems, such as meter-level RC systems.

[0003] On the other hand, in existing technologies, the realization of visible light imaging and laser communication functions usually employs two independent optical systems, or constructs a common optical path design by adding beam splitting and combining elements. This technical approach has become a core obstacle restricting the integrated development of optical systems. For example, patent CN202411623080.X discloses an aberration correction method for a liquid mirror telescope. This method uses a three-mirror architecture consisting of a primary mirror, a secondary mirror, and a magnetofluid deformable mirror. Although it can achieve off-axis aberration correction, it only has a single imaging function and lacks laser communication capabilities. At the same time, this scheme requires two additional sets of plane mirrors to adjust the beam direction, and the redundant structural design results in high system weight and cost.

[0004] In summary, existing technologies suffer from the following shortcomings: First, liquid zoom lenses cannot be effectively adapted to large-aperture RC systems, failing to achieve synergistic optimization of zoom and aberration correction; second, the integration of visible light imaging and laser communication / ranging relies on additional components, making it difficult to balance lightweight design and high performance; third, existing integrated solutions are either functionally limited or constrained by aperture and beam splitting efficiency, failing to meet the practical needs of high-end optoelectronic fields. Therefore, developing an integrated solution that requires no additional optical components, achieves deep integration of liquid zoom lenses and RC systems, and combines imaging and laser communication functions has become an urgent need in the current optoelectronic technology field. Summary of the Invention

[0005] This invention addresses the problems in existing technologies where large-aperture reflective systems cannot use liquid lens zoom, resulting in large size and low reliability of structural component displacement focusing systems; and the separation of visible light imaging and laser communication systems, leading to large size and high cost, and making it difficult to balance lightweight and high performance. The invention provides a large-aperture reflective zoom and laser communication integrated camera.

[0006] A large-aperture reflective zoom and laser communication integrated camera, the camera including a primary mirror, a secondary mirror, a visible light detector and an infrared detector; the secondary mirror is composed of a liquid zoom lens array and a grating film to form the secondary mirror structure of a large-aperture RC optical system.

[0007] The liquid zoom lens array integrates multiple layers of liquid zoom lenses, each layer of the lens consists of one or more liquid zoom lens units, and each layer of the lens is controlled by an independent driving circuit; the back surface of the liquid zoom lens array is a planar structure without curvature.

[0008] The mixed beam is reflected by the primary mirror and then incident on the liquid zoom lens array. The beam reflected back to the liquid zoom lens array by the grating film finally forms a high-resolution image on the focal plane of the visible light detector; the beam transmitted by the grating film finally forms an infrared image on the infrared detector.

[0009] The beneficial effects of this invention are:

[0010] 1. The camera described in this invention achieves continuous zoom of a large-aperture RC reflection system for the first time through a multi-layer liquid zoom lens array, and can accurately correct aberrations under different apertures. The system contains no moving mechanical components, significantly improving image quality and system reliability. It integrates large-aperture visible light imaging, liquid zoom, and 1550nm laser communication functions.

[0011] 2. In the camera described in this invention, a grating film is used to achieve efficient separation and multiplexing of visible light and laser light, avoiding energy loss and image quality degradation caused by traditional beam splitting elements.

[0012] 3. The camera described in this invention integrates large-aperture visible light imaging and 1550nm laser communication functions into a single optical system, eliminating the need for additional beam splitting / combining elements and significantly reducing the system's size, weight, and cost. It combines high-resolution imaging with long-distance communication capabilities, making it widely applicable in aerospace, aviation, and ground-based observation scenarios.

[0013] 4. The camera described in this invention only includes a primary mirror, a liquid zoom lens array, a grating film, a visible light detector, and an infrared detector. It has fewer core components, a simpler structure, reduces potential failure points, and improves the system's environmental adaptability and reliability. Attached Figure Description

[0014] Figure 1 This is a schematic diagram illustrating the principle of a large-aperture reflective zoom and laser communication integrated camera according to the present invention.

[0015] Figure 2 This is a cross-sectional view of the secondary mirror in a large-aperture reflective zoom and laser communication integrated camera according to the present invention.

[0016] Figure 3 This is a schematic diagram of the structure of a multi-layer liquid zoom lens array in a large-aperture reflective zoom and laser communication integrated camera according to the present invention.

[0017] Figure 4 This is a schematic diagram of the visible light imaging path in a large-aperture reflective zoom and laser communication integrated camera according to the present invention.

[0018] Among them, 1. primary mirror, 2. secondary mirror, 3. visible light detector, 4. infrared detector, 21. liquid zoom lens array, 22. grating film. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0020] Combination Figures 1 to 4 This embodiment describes a large-aperture reflective zoom and laser communication integrated camera, comprising: a primary mirror 1, which is located at the front end of the entire camera optical path and has a parabolic or hyperboloidal surface shape, and plays the role of controlling the amount of light entering the camera and adjusting the light; a secondary mirror 2, which consists of a liquid zoom lens array 21 and a grating film 22, wherein the light incident on the secondary mirror 2 reflects visible light and transmits 1550nm laser light, thereby splitting the light and finally imaging it onto a visible light detector 3 and an infrared detector 4 respectively.

[0021] like Figure 1 As shown, the mixed light is reflected by the primary mirror 1 and transmitted to the liquid zoom lens on the front of the liquid zoom lens array 21. Then, the visible light is reflected by the grating film 22 and transmitted again through the liquid zoom lens, finally converging onto the visible light detector 3 to form an RC-type visible light imaging optical path.

[0022] After being reflected by the primary mirror 1, the mixed light is transmitted to the liquid zoom lens on the front of the liquid zoom lens array. Then, the 1550nm laser is transmitted through the grating film and finally converges onto the infrared detector 4 to form a laser communication optical path.

[0023] like Figure 2 As shown, Figure 2This is a cross-sectional view of the secondary mirror 2, specifically a cross-sectional view of the liquid zoom lens array and the grating film. The secondary mirror is a secondary mirror structure of a large-aperture RC optical system, consisting of the liquid zoom lens array 21 and the grating film 22. When mixed light is incident on the secondary mirror, the light first passes through the liquid zoom lens array 21 to transmit the mixed light, and then it is incident on the grating film 22. When visible light is incident, the grating film 22 couples most of the visible light energy into the -1st order diffracted light. This diffracted light is reflected at a certain angle, thus achieving high reflectivity for visible light. When laser light is incident, the laser energy is mainly concentrated in the 0th order diffracted light, achieving high transmission of the laser light. Thus, integrated imaging of visible light and laser light is achieved.

[0024] like Figure 3 As shown, Figure 3 This is a schematic diagram of the liquid zoom lens array 21. The array employs a multi-layer stacked liquid zoom lens configuration, with its back surface being a flat, non-curved structure. Each layer of the liquid zoom lens array 21 can be independently electronically controlled for focal length adjustment. Each layer consists of one or more liquid zoom lens units. For example, the first layer consists of one liquid zoom lens unit and is adjusted by drive circuit 1; the second layer consists of six liquid zoom lens units and is adjusted by drive circuit 2; and the third layer consists of twelve liquid zoom lens units and is adjusted by drive circuit 3. The total number of lens units and the number of layers are related as follows: N = 3S 2 -3S-1, where N is the total number of lens units and S is the number of layers of the liquid zoom lens. By precisely controlling the focal length of different lens layers, aberration modulation can be achieved in different aperture regions of the entire optical system.

[0025] like Figure 4 As shown, Figure 4 This is a schematic diagram of the visible light imaging path, which consists of a primary mirror 1, a liquid zoom lens array 21, a grating film 22, and a visible light detector 3. Visible light, after being reflected by the primary mirror 1, is incident on the liquid zoom lens array 21, and is reflected back to the liquid zoom lens array 21 by the grating film 22 on the back side. Finally, a high-resolution image is formed on the focal plane of the visible light detector 3, constituting an RC-type reflective optical system. In this visible light imaging path, the light beam passes through the liquid zoom lens twice; therefore, the liquid zoom lens array modulates the light beam twice.

[0026] Each liquid lens unit in the liquid zoom lens array 21 is a dual-liquid type, consisting of two immiscible liquids with different refractive indices, and the focus is adjusted by changing the interface curvature. Multiple liquid lens units are arranged in a symmetrical, layered manner around the center to form the liquid zoom lens array, and the focal length of each layer of liquid lenses can be adjusted independently.

[0027] The grating film 22 has high reflectivity for visible light and high transmittance for 1550nm laser light. When visible light is incident, the grating film 22 couples most of the visible light energy into the -1st order diffracted light. This diffracted light is reflected at a certain angle, thereby achieving high reflectivity for visible light and ensuring that it is reflected back into the liquid zoom lens array 21.

[0028] In this embodiment, the liquid zoom lens array achieves a large aperture through a multi-layer hexagonal array distribution. The more array layers there are, the larger the aperture will be, which is usually no more than 1 / 3 of the primary lens aperture.

[0029] In this embodiment, the grating film 22 efficiently reflects visible light, wherein the diffraction angle β satisfies the grating equation:

[0030]

[0031] Where k is the grating constant, α is the incident angle, β is the diffraction angle, m is the diffraction order (taken as -1), and λ is the wavelength.

[0032] Set the focal length of primary mirror 1 to be An object at infinity is imaged after passing through the primary mirror. According to Gauss's formula, the position s1 of the image point incident on the liquid zoom lens array is:

[0033]

[0034] When the light passing through the primary mirror 1 first reaches the liquid zoom lens array 21, the image distance v1 after passing through the liquid zoom lens is calculated as follows:

[0035]

[0036] Where v1 is the image distance after passing through the liquid zoom lens array. Let be the focal length of each layer of the liquid lens to be determined.

[0037] Since the grating film 22 is a planar grating, diffraction changes the angle of the light rays but does not change the object distance. Different wavelengths correspond to different incident / diffraction angles. Therefore, the object distance u2 at the grating film 22 is: Where d is the distance from the liquid zoom lens array to the grating film. Then the reflected image distance u2' is: The object distance u3 of the light rays reflected by the grating film 22 that re-enters the liquid zoom array 21 is: The final image distance v3 is calculated using the following formula:

[0038]

[0039] Therefore, we get:

[0040]

[0041] Substituting into the formula, we get:

[0042]

[0043] Therefore, based on the position s1 of the principal image point in front of the lens after passing through the primary mirror 1, the focal length of the liquid zoom lens array is... The total focal length F of the visible light path can be calculated by finding the distance d from the liquid zoom lens array to the grating film.

[0044] In this embodiment, the primary mirror 1 in the system uses a large-aperture concave mirror (usually a parabolic or hyperboloidal surface). Therefore, the axial distance from the focal point of the primary mirror to the lens array varies with the height of different layers of the lens array. Thus, it is necessary to adjust the focal length of each layer of the liquid lens array 21 to achieve aberration correction and ensure clear imaging of the entire image plane. The primary mirror provides the system with basic light-gathering capability, and its aperture can reach the meter level.

[0045] In this embodiment, the laser communication imaging optical path consists of a primary mirror 1, a liquid zoom lens array 21, a grating film 22, and an infrared laser detector 4. When a 1550nm laser signal is reflected by the primary mirror 1, it enters the liquid zoom lens array 21, is then transmitted through the grating film 22, and finally enters the infrared detector 4 of the laser communication receiving module.

[0046] The planar grating film 22 exhibits high laser transmission, where the diffraction angle β must also satisfy the grating equation:

[0047]

[0048] Where k is the grating constant, α is the incident angle, β is the diffraction angle, and m is the diffraction order.

[0049] Lasers are characterized by their extremely high monochromaticity. The energy of the laser is mainly concentrated in the 0th order diffraction. Therefore, setting m to 0 for the laser imaging path can achieve high transmission of the laser. Thus, the grating film only serves as a transmission plane for the laser's optical path.

[0050] Given the total focal length F of the visible light imaging path, the distance d from the lens array to the grating, and the focal length of the liquid zoom lens array... and the focal length of the primary lens Based on this, the focal length F2 of the laser imaging optical path can be calculated:

[0051]

[0052] Since the laser imaging optical path and the visible light imaging optical path share the primary mirror 1 and the liquid zoom lens array 21, it is possible to achieve the desired result by properly allocating the focal length of the primary mirror. and the focal length of the liquid zoom lens array This allows both the total focal length F of the visible light and the total focal length F2 of the laser path to be accurately focused onto their respective receiving detectors, ensuring clear visible light imaging while achieving optimal coupling efficiency in laser reception.

[0053] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A large-aperture reflective zoom and laser communication integrated camera, the camera comprising a primary mirror, a secondary mirror, a visible light detector, and an infrared detector; characterized in that: The secondary mirror is a secondary mirror structure of a large-aperture RC optical system composed of a liquid zoom lens array and a grating film. The liquid zoom lens array integrates multiple layers of liquid zoom lenses, each layer of the lens consists of one or more liquid zoom lens units, and each layer of the lens is controlled by an independent driving circuit; the back surface of the liquid zoom lens array is a planar structure without curvature. The mixed beam is reflected by the primary mirror and then incident on the liquid zoom lens array. The beam reflected back to the liquid zoom lens array by the grating film finally forms a high-resolution image on the focal plane of the visible light detector; the beam transmitted by the grating film finally forms an infrared image on the infrared detector.

2. The large-aperture reflective zoom and laser communication integrated camera according to claim 1, characterized in that: Each liquid zoom lens unit in the liquid zoom lens array is a dual-liquid type, and multiple liquid zoom lens units are arranged in a symmetrical layered manner around the center to form the liquid zoom lens array.

3. The large-aperture reflective zoom and laser communication integrated camera according to claim 1, characterized in that: The driving circuit in each lens layer adjusts the lens of its own layer individually by electronic control, so that the focal length of each lens layer in the liquid zoom lens array is different. This is used to correct aberrations and achieve focusing for optical systems with different apertures.

4. A large-aperture reflective zoom and laser communication integrated camera according to claim 1, characterized in that: The back surface of each lens layer is a flat structure without curvature.

5. The large-aperture reflective zoom and laser communication integrated camera according to claim 1, characterized in that: The relationship between the total number of lens units and the number of lens layers in the liquid zoom lens array is: N=3S 2 -3S-1, where N is the total number of lens units and S is the number of layers of the liquid zoom lens.

6. A large-aperture reflective zoom and laser communication integrated camera according to claim 1, characterized in that: The grating film is deposited on the back side of the liquid zoom lens array, and the grating film is deposited to provide high reflectivity for visible light, while having high transmittance for the 1550nm laser band. The grating film is a planar grating; where the diffraction angle β satisfies the grating equation: ； In the formula, k is the grating constant, α is the incident angle, β is the diffraction angle, m is the diffraction order, and λ is the wavelength; When visible light is incident, m is set to -1. The planar grating couples the visible light energy into the -1st order diffracted light. The -1st order diffracted light is deflected on the opposite side of the incident light, achieving high reflectivity for visible light. When laser light is incident, m is set to 0, so that the laser energy is concentrated in the 0th order diffracted light, achieving high transmission of the laser, thereby realizing integrated imaging of visible light and laser.

7. A large-aperture reflective zoom and laser communication integrated camera according to claim 6, characterized in that: Based on the position s1 of the primary image point in front of the lens after passing through the primary mirror, the focal length of the liquid zoom lens array, and the distance d from the liquid zoom lens array to the grating film, the total focal length F of the visible light path is obtained; and based on the total focal length F of the visible light path and the focal length of the primary mirror, the focal length F2 of the laser imaging path is obtained.

8. A large-aperture reflective zoom and laser communication integrated camera according to claim 7, characterized in that: The process for obtaining the total focal length F of the visible light optical path is as follows: Set the focal length of the primary lens to An object at infinity is imaged after passing through the primary mirror. The position s1 of the image point incident on the liquid zoom lens array is obtained using Gauss's formula. ； When the light passing through the primary mirror first reaches the liquid zoom lens array, the image distance v1 after passing through the liquid zoom lens is calculated as follows: ； In the formula, Let be the focal length of each layer of liquid zoom lens to be determined; The object distance u2 at the grating film is: Then the reflected image distance u2' is: ; The object distance u3 at which the light rays, after being reflected by the grating film, re-enter the liquid zoom lens array is: ； The final image distance v3 is obtained as follows: ； We can obtain: ; The final total focal length F of the visible light path is: 。 9. A large-aperture reflective zoom and laser communication integrated camera according to claim 7, characterized in that: The focal length F2 of the laser imaging optical path is expressed by the following formula: ； In the formula, The focal length of the primary mirror, Let be the focal length of each layer of the liquid zoom lens to be determined.

Images