A large depth of field miniature artificial compound eye imaging system, a preparation method and applications thereof

Abstract

The application discloses a large-landscape-depth miniature artificial compound eye imaging system, a preparation method and application, belongs to the technical field of photoelectric devices, and comprises a compound eye lens, an objective lens and a microscopic observation system; the objective lens is located behind the compound eye lens and is aligned with the center line of the compound eye lens, and the microscopic observation system is located behind the objective lens and receives imaging information; the compound eye lens comprises a spherical crown base, a central sub-eye, a first circle of sub-eyes and a second circle of sub-eyes; the central sub-eye is located at the top of the spherical crown base, and the first circle of sub-eyes and the second circle of sub-eyes are arranged in the first circle and the second circle around the central sub-eye; the compound eye is composed of three different sub-eyes in the application, and the surface type of the sub-eyes is the combination of two lenses with different curvature radii; the two lenses with different focal lengths are used for observing images at different distances respectively, so that the compound eye can clearly observe two objects on different planes at the same time; the 'femtosecond laser additive manufacturing' technology is used for high-precision preparation of the large-landscape-depth miniature bionic artificial compound eye, the prepared artificial compound eye is combined with the microscopic observation system, and finally the preparation of the large-landscape-depth miniature artificial compound eye imaging system is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic devices, and in particular relates to a micro artificial compound eye imaging system with a large depth of field, a preparation method and an application thereof. Background Art

[0002] After hundreds of millions of years of evolution, arthropods have developed a visual system called a compound eye, composed of numerous evenly spaced photoreceptors. Each photoreceptor typically consists of a corneal lens, cones, a bundle of rods, and optic nerves. The insect compound eye is characterized by its compact size, large field of view, and sensitivity to moving objects, which helps insects acquire environmental information, capture prey, avoid predators, and identify mates. Based on these characteristics, researchers have developed micro-bionic artificial compound eye imaging systems modeled after the structure of insect compound eyes, which are finding applications in military navigation, intelligent sensing, micro-robotic vision, and medical endoscopy.

[0003] An imaging system usually consists of two parts: an image acquisition system—a compound eye lens—and an image receiving system. Currently, there are still difficulties in preparing bionic artificial compound eye lenses. In practical applications, it is usually necessary to clearly observe both near and far objects at the same time. Traditional single-focal-length compound eye lenses, based on the convex lens imaging formula, know that one object distance corresponds to one image distance, making it difficult to clearly observe objects on different planes in the same area at the same time. To address this issue, researchers have designed a lens with adjustable focal length, driven by electromagnetic force or electrothermal drive. Although the lens can zoom and image, this method has the disadvantages of complex driving methods, slow response time, and limited application environments. So far, how to prepare a high-performance curved compound eye lens that can observe both near and far objects simultaneously without being driven is of great significance and challenge. Summary of the Invention

[0004] To address the shortcomings of the existing technology, the present invention provides a simple, externally driven, large-field-of-view, and large-depth-of-field micro-artificial compound eye imaging system and its preparation method. The present invention utilizes a compound eye composed of three different sub-eyes, each of which is a combination of lenses with two different curvature radii. These two lenses, each with different focal lengths, observe images at different distances, allowing the compound eye to clearly observe two objects on different planes simultaneously, thus resolving the limited depth of field of traditional compound eye lenses. The present invention then utilizes "femtosecond laser additive manufacturing" technology to precisely fabricate a micro-bionic artificial compound eye with a large depth of field. This artificial eye is then combined with a microscopic observation system to ultimately achieve the fabrication of a micro-artificial compound eye imaging system with a large depth of field.

[0005] The present invention is achieved through the following technical solutions:

[0006] In the first aspect, the present invention provides a miniature artificial compound eye imaging system with a large depth of field, comprising a compound eye lens 1, an objective lens 2 and a microscopic observation system 3; wherein the objective lens 2 is located behind the compound eye lens 1 and aligned with the center line of the compound eye lens 1, and the microscopic observation system 3 is located behind the objective lens 2 to receive imaging information; the compound eye lens 1 comprises a spherical crown base 4, a central sub-eye 5, a first circle eye 6 and a second circle eye 7; the central sub-eye 5 is located at the vertex of the spherical crown base 4, and the first circle eye 6 and the second circle eye 7 surround the first circle and the second circle of the central sub-eye 5; wherein the central sub-eye 5, the first circle eye 6 and the second circle eye 7 are all composite lens structures composed of a large lens 8 and a small lens 9; the small lens 9 is located above the large lens 8; the central sub-eye 5, the first circle eye 6 and the second circle eye 7 are all located on the surface of the spherical crown base 4 and the centerline angles of adjacent sub-eyes are The field of view of the fly-eye lens 1 is The focal lengths of the large lens 8 and the small lens 9 vary with the angles between the center lines of the sub-eyes where they are located and the center line of the central sub-eye 5 .

[0007] Furthermore, the focal lengths of the large lenses 8 in the first circle eye 6 and the second circle eye 7 are L2 and L3, respectively, which are calculated by the following formula:

[0008]

[0009] Among them, L1 is the focal length of the large lens 8 in the central sub-eye 5, R o is the radius of the sphere where the spherical cap base 4 is located, is the field of view of the fly-eye lens 1, It is the angle between the center lines of adjacent sub-eyes.

[0010] Furthermore, the focal lengths of the small lenses 9 in the central sub-eye 5, the first circle eye 6, and the second circle eye 7 are l1, l2, and l3, respectively, which are calculated using the convex lens imaging formula:

[0011]

[0012] Among them, W min is the minimum object distance.

[0013] Furthermore, L1 is 675.00-800.00 μm, and the field of view angle The range is 100°-110°; the minimum object distance is W min The range is 150-675μm.

[0014] Furthermore, the central sub-eye 5, the first circle eye 6 and the second circle eye 7 are closely arranged on the spherical cap base 4; the radius of the central sub-eye 5 is The centers of the large lens 8 and the small lens 9 of the central sub-eye 5, the first circle eye 6 and the second circle eye 7 are respectively on the center line of each sub-eye and the distance between the centers ranges from 90 to 130 μm.

[0015] In a second aspect, the present invention further provides a method for preparing a micro artificial compound eye imaging system with a large depth of field, the specific steps of which are as follows:

[0016] (1) Sample preparation;

[0017] Specific steps: First, drop the optical resin on the substrate; place the substrate on a hot table for heating and pre-baking, and then cool it naturally at room temperature;

[0018] (2) Leveling processing system;

[0019] The specific steps are as follows: Place the prepared substrate in the galvanometer-based femtosecond laser direct writing processing system, adjust the laser energy to a reference value, focus the laser on the interface between the polymer film formed after pre-baking the optical resin and the substrate, and rotate the stage support screws to ensure that the spot energy remains unchanged when moving left and right and forward and backward. At this point, the stage is considered to be leveled; then, control the laser focus to the interface between the optical resin and the substrate and focus it deep into the substrate.

[0020] (3) Preparation of micro artificial compound eyes with large depth of field and integration of imaging systems;

[0021] The specific steps are as follows: generate the point cloud data of the designed micro compound eye lens 1 into the file to be processed; set the laser processing power and perform point-by-point scanning processing; develop, dry and ultraviolet-expose the scanned substrate to finally prepare a micro curved artificial compound eye lens 1 with a large depth of field; finally, seal the compound eye lens 1 and align it with the microscopic observation system 3 to complete the integration of the imaging system.

[0022] Furthermore, in step one, the optical resin is a variety of ultraviolet optical resins that can be prepared by femtosecond laser two-photon polymerization, mainly including: epoxy resin SU-8, organic / inorganic hybrid photoresist IP-DIP, SZ2080, ultraviolet optical curing glue NOA61, NOA63, etc.; the substrate is placed on a hot table for pre-heating, the drying temperature is 50-150°C, and the drying time is 5-30 minutes; to avoid photoresist exposure failure, the photoresist dripping and heating process are both carried out under a yellow light environment; the photoresist liquid collection tool is a rubber-tipped dropper, and the liquid collection dosage is 1 drop; a constant temperature heating table is used to heat the substrate; the substrate pre-baking heating temperature is 90-120°C, and the heating time is 90-120 minutes; the substrate size is 24*24*0.14mm; after pre-baking, it is naturally cooled at room temperature.

[0023] Furthermore, in step 2, the galvanometer-based femtosecond laser direct writing processing system includes a fiber femtosecond laser oscillator, an attenuation plate, an optical gate, a reflector, a beam expansion system, a scanning galvanometer, a 4F optical system and an oil-immersion objective lens; the femtosecond pulse laser generated by the femtosecond laser oscillator passes through the attenuation plate and the optical gate, passes through the reflector and then passes through the beam expansion system, the expanded laser beam controls the beam deflection angle through the scanning galvanometer, and then the laser beam is projected onto the entrance pupil of the objective lens by the 4F optical system, and the beam is focused into the processing sample through the oil-immersion objective lens, and combined with the movement of the translation stage to achieve three-dimensional scanning; at the same time, a real-time monitoring system composed of an illumination light source, a filter, and an imaging CCD is used to observe the status of the sample during processing in real time;

[0024] The femtosecond laser center wavelength of the galvanometer-based femtosecond laser direct writing processing system is 780nm, the pulse width is 80-180fs, and the repetition frequency is 85-100MHz; the attenuator is a gradient density filter with an operating wavelength of 400-1100nm; the reflector is a dielectric film reflector with an operating wavelength of 800nm; the lens of the 4F optical system is a K9 glass plano-convex lens with a focal length of 100-300mm.

[0025] Furthermore, in step 3, the laser processing power is 15-30 mW, and the single-point exposure time is 200-1000 μs. After laser processing is completed, the substrate is removed and then placed diagonally in a beaker with the photoresist side facing downward. N-propanol is poured along the beaker wall to cover the photoresist for development. The photoresist development time is 10-90 minutes. The UV lamp used for UV exposure has a wavelength of 300-450 nm, a power of 1-10 W, and an exposure time of 5-60 minutes. All of the above operations are performed under yellow light.

[0026] In step three, a cavity is sealed on the substrate and water is injected to place the compound eye lens 1 in a water environment. The microscopic observation system 3 is then aligned with the compound eye lens 1 to complete the integration of the compound eye imaging system.

[0027] In a third aspect, the present invention also provides an application of a micro-artificial compound eye imaging system with a large depth of field in image detection in space, specifically using the micro-artificial compound eye imaging system to perform real-time observation of objects at different distances in space.

[0028] Compared with the prior art, the advantages of the present invention are as follows:

[0029] (1) The present invention provides a micro-artificial compound eye imaging system with a large depth of field, a preparation method, and an application thereof, which solves the problem of limited depth of field of the curved surface artificial compound eye by specially designing the sub-eye function surface;

[0030] (2) Through femtosecond laser two-photon polymerization-assisted contour scanning, high-precision and rapid preparation of special surface-shaped micro-artificial compound eyes was achieved;

[0031] (3) Successfully combined a micro-curved artificial compound eye with a microscopic observation system to achieve the preparation of a micro-artificial compound eye imaging system with a large depth of field;

[0032] (4) The artificial compound eye imaging system and preparation method have the outstanding advantages of simple design, universal method, strong operability and wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly describes the drawings required for the specific embodiments or the description of the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0034] Figure 1 Schematic diagram of a micro artificial compound eye imaging system with a large depth of field;

[0035] Figure 2 Schematic diagrams of the working principles of a conventional uniform curved compound eye lens (a) and a large depth-of-field curved compound eye lens (b) prepared according to the present invention;

[0036] Figure 3 This is a schematic diagram of the optical path for the preparation of a large-depth-of-field micro-artificial compound-eye lens - femtosecond laser two-photon polymerization-assisted shell scanning processing of the present invention;

[0037] Figure 4 This is a scanning electron microscope characterization image of the large depth of field micro artificial compound eye lens 1 prepared according to the present invention;

[0038] Figure 5 Schematic diagram of the focusing test optical path of the large depth of field micro artificial compound eye lens 1 prepared by the present invention;

[0039] Figure 6 The light spot energy distribution on two focusing planes of the large depth of field micro artificial compound eye lens 1 prepared by the present invention;

[0040] Wherein, a is the light spot energy distribution on the focal plane of the small lens 9 in all sub-eyes; b is the light spot energy distribution on the focal plane of the large lens 8 in all sub-eyes;

[0041] Figure 7 Schematic diagram of the test of the large depth of field micro artificial compound eye imaging system prepared by the present invention;

[0042] Figure 8 This is a diagram of the large depth of field micro artificial compound eye lens 1 prepared by the present invention imaging two different space objects;

[0043] Wherein, a is the individual imaging of the number "3" at a distance of 190 microns from the compound eye lens, and b is the imaging of the letter "f" at a distance of 10 cm from the compound eye lens;

[0044] Figure 9 The large-depth-of-field miniature artificial compound eye imaging system prepared by the application directly collects images of two objects in different planes. DETAILED DESCRIPTION

[0045] In order to clearly and completely describe the technical solutions of the application and the specific working process thereof, the specific embodiments of the application are as follows in combination with the accompanying drawings of the specification:

[0046] Example 1

[0047] The application expands the imaging depth of field of the bionic artificial compound eye lens by designing a special function surface of the sub-eye, so that the focusing light spots of the sub-eye are distributed in two planes and imaged in one plane, thereby achieving the reception of the imaging of all sub-eyes at a certain plane position. The device is prepared by a femtosecond laser additive manufacturing auxiliary shell layer scanning technology to obtain a high-precision curved surface profile in accordance with the design, thereby realizing wide field of view and large depth of field image acquisition.

[0048] Specifically, a large-depth-of-field miniature artificial compound eye imaging system comprises a compound eye lens 1, an objective lens 2 and a microscopic observation system 3; wherein the objective lens 2 is located behind the compound eye lens 1 and is aligned with the center line of the compound eye lens 1, and the microscopic observation system 3 is located behind the objective lens 2 to receive imaging information; the compound eye lens 1 comprises a spherical crown base 4, a center sub-eye 5, a first circle of sub-eyes 6 and a second circle of sub-eyes 7; the center sub-eye 5 is located at the top of the spherical crown base 4, and the first circle of sub-eyes 6 and the second circle of sub-eyes 7 are arranged in the first circle and the second circle around the center sub-eye 5; wherein the center sub-eye 5, the first circle of sub-eyes 6 and the second circle of sub-eyes 7 are all composed of a composite lens structure of a large lens 8 and a small lens 9; the small lens 9 is located above the large lens 8; the center sub-eye 5, the first circle of sub-eyes 6 and the second circle of sub-eyes 7 are all located on the surface of the spherical crown base 4, and the center lines of adjacent sub-eyes all have an included angle of 60 degrees. The field of view angle of the compound eye lens 1 is 180 degrees. The focal lengths of the large lens 8 and the small lens 9 change with the included angle between the center line of the sub-eye and the center line of the center sub-eye 5.

[0049] In this embodiment, the focal lengths of the large lenses 8 in the first circle of sub-eyes 6 and the second circle of sub-eyes 7 are L2 and L3 respectively, which are calculated by the following formula:

[0050]

[0051] Wherein, L1 is the focal length of the large lens 8 in the center sub-eye 5, R o is the radius of the sphere where the spherical crown base 4 is located, is the field of view angle of the compound eye lens 1, It is the angle between the center lines of adjacent sub-eyes.

[0052] The focal lengths of the small lenses 9 in the central sub-eye 5, the first circle eye 6, and the second circle eye 7 are l1, l2, and l3, respectively, which are calculated using the convex lens imaging formula:

[0053]

[0054] Among them, W min is the minimum object distance.

[0055] In this embodiment, L1 is 675.00-800.00 μm, and the field angle The range is 100°-110°; the minimum object distance is W min The range is 150-675μm.

[0056] Example 2

[0057] This embodiment provides a method for preparing a micro artificial compound eye imaging system with a large depth of field, and the specific steps are as follows:

[0058] (1) Design of compound eye lens

[0059] Specific steps: First, the central sub-eye 5, the first circle eye 6 and the second circle eye 7 are designed to be evenly distributed on the spherical crown base 4. The radius and height of the spherical crown base 4 are 150μm and 75μm respectively; the radius of the central sub-eye 5, the first circle eye 6 and the second circle eye 7 are all 40μm. It is calculated that the radius of the arc distributed on the spherical crown base 4 is about 187.50μm, the angle between the sub-eyes is about 21.25°, and the field of view of the entire compound eye lens 1 is about 106.25°. In this embodiment, the compound eye operates in a water environment with a refractive index of 1.33. In addition, the experimental resin of the compound eye lens 1 is a new type of organic-inorganic hybrid polymer SZ-2080. The refractive index of the resin is 1.5, so the refractive index difference is 0.17. The focal length of the large lens 8 of the central sub-eye 5 is set to 675.00μm. The focal lengths of the large lenses 8 of the first and second rings of eyes 6 and 7 can be calculated from the angle between the sub-eyes, resulting in 710.56μm and 848.71μm, respectively. Since the substrate thickness is approximately 140μm, the height of the compound eye 1 is approximately 90μm, and the object distance after sealing is approximately 190μm, the convex lens imaging formula shows that the focal lengths of the small lenses 9 of the central sub-eye 5, the first and second rings of eyes 6, and 7 are set to 150.00μm, 151.69μm, and 157.15μm, respectively. The centers of the large lenses 8 and small lenses 9 of the central sub-eye 5, the first and second rings of eyes 6, and 7 are located on their respective sub-eye centerlines, and the distance between the centers is 97.17μm, 102.85μm, and 125.18μm, respectively. Using the formula for the relationship between lens focal length and curvature, the curvature radii of large lens 8 for the central sub-eye 5, first circle eye 6, and second circle eye 7 are approximately 114.75 μm, 120.80 μm, and 144.28 μm, respectively. The curvature radii of small lens 9 for the central sub-eye 5, first circle eye 6, and second circle eye 7 are approximately 25.50 μm, 25.79 μm, and 26.72 μm, respectively.

[0060] After determining the focal length design of the compound eye lens 1, the height distribution of the lens at different positions can be obtained based on the functional surface equation of the spherical lens. Then, the height information of the surface contour of the compound eye lens 1 can be calculated based on the height and radius of the spherical crown base 1. Through C++ programming, a program is written to output the surface contour information of the device as three-dimensional point cloud data, and export it to a Txt text in the data format of (x, y, z, l), where x, y, z are position information, and l is the light gate switch (0 represents the light gate closed, 1 represents the light gate open). This embodiment uses a contour scanning processing method to produce the compound eye. Taking the outer contour of the compound eye as a reference, the shell layer with a shell thickness of 2μm is expanded inward, and the point cloud data of the micro compound eye lens 1 is generated into the file to be processed.

[0061] (2) Sample preparation and system leveling;

[0062] Specific steps: first, the substrate sheet is prepared, and the substrate sheet is ultrasonically cleaned in an ultrasonic machine for 10 minutes to remove large-size debris and dust particles on the surface. A cotton ball soaked in anhydrous ethanol is used to wipe the substrate sheet, and then deionized water is used to rinse the surface to remove residual ethanol, and then the substrate sheet is dried in a vacuum drying oven at 70° for 5 minutes; a drop of optical resin SZ2080 is taken with a rubber dropper and added to the surface of the substrate sheet; the substrate sheet is placed on the heating table for pre-baking, the pre-baking temperature is 100°, and the pre-baking time is 90 minutes, and then the substrate sheet is cooled at room temperature.

[0063] Next, the fly-eye lens 1 is prepared by a galvanometer-based femtosecond laser direct writing processing system as shown in Figure 3 The cooled substrate sheet is placed on the stage of the galvanometer-based femtosecond laser direct writing processing system. The femtosecond pulse laser (center wavelength 800 nm, pulse width 100 fs, repetition frequency 80 MHz) generated by the femtosecond laser oscillator passes through the attenuator and the shutter in turn, then passes through the mirror and the beam expansion system, so that the laser beam with the size expanded by five times is controlled by the scanning galvanometer to control its deflection angle, and then the angle deflection of the laser beam is projected into the objective lens entrance pupil by the 4F optical system. The oil immersion objective lens produced by Olympus Company with a numerical aperture of 1.35 and a magnification of 60 times tightly focuses the incident light inside the processing sample, thereby achieving three-dimensional scanning processing. At the same time, the real-time monitoring system composed of an illumination source, a filter and a CCD can observe the state of the sample processing in real time. The illumination source uses a white LED light source; the filter uses a waveband selection absorption type filter with a transmission range of 580-2300 nm; and the real-time observation system CCD is a domestic high-definition drive-free industrial camera. Before formal processing, the laser energy is adjusted to the reference value, the laser is focused to the interface position between the polymer film and the substrate sheet, and the spot energy remains unchanged when the stage support screw is rotated to move 500 μm left and right and up and down. At this time, it can be determined that the stage has been leveled.

[0064] (3) Preparation of a large-depth miniature artificial compound eye;

[0065] The specific steps are: open the point cloud file of the fly-eye lens 1 generated in step (2). Adjust the position of the attenuator so that the measured laser power in front of the objective lens reaches 23.0 mw. Finally, set the single-point exposure time to 100 μs on the processing software, and click the start button to start the point-by-point scanning processing.

[0066] Then, the device is developed and dried: the processed substrate sheet is immersed in the photoresist developer n-propanol for development for 60 minutes. After development, the substrate sheet is taken out of the developer and naturally dried.

[0067] Finally, the post-processing of the device: after drying the compound eye lens 1 under high-power ultraviolet lamp irradiation for 5 min, the ultraviolet lamp power is 1 W, so that the resin which is not exposed in the femtosecond laser direct writing process except the scanning shell layer is polymerized, and the long-term stability of the structure is improved. Finally, the large depth of field micro-curved artificial compound eye lens 1 is prepared.

[0068] As Figure 1 It can be seen that the large depth of field micro-artificial compound eye imaging system schematic diagram;

[0069] Among them, the designed large depth of field compound eye lens 1 structure is composed of central sub-eye 5, first circle sub-eye 6 and second circle sub-eye 7; each sub-eye is a composite structure composed of two kinds of different curvature radius lenses, which are large lens 8 and small lens 9; wherein the focal length of the large lens 8 and the small lens 9 is different according to the position of the sub-eye;

[0070] As Figure 2 As shown in (a) of the prior art, the traditional uniform curved compound eye lens structure is as shown in the figure, the distant trees and the near butterfly are imaged in two curved planes, and cannot accept the imaging of the two objects in the same plane. As Figure 2 As shown in (b) of the prior art, the large depth of field curved compound eye lens designed in this embodiment can make the small lens 9 detect the object in the near place, and the large lens 8 detect the object in the far place, and the imaging of the two lenses is in the same plane;

[0071] As Figure 3 It can be seen that the optical path diagram of the femtosecond laser two-photon polymerization auxiliary shell scanning processing;

[0072] Among them, the femtosecond pulse laser generated by the femtosecond laser oscillator passes through the attenuator and the shutter, passes through the reflecting mirror through the beam expansion system, the laser beam is expanded by 5 times after the laser beam is expanded by 5 times, and then the deflection angle of the laser beam is controlled by the scanning galvanometer. Then the laser beam is projected to the objective lens entrance pupil by the 4F optical system, the light beam is focused to the inside of the processing sample by the oil immersion objective lens, and the three-dimensional scanning is realized by combining with the movement of the displacement table.

[0073] As Figure 4 It is a scanning electron microscope photo of the large depth of field micro-artificial compound eye lens 1 prepared in this embodiment;

[0074] Among them, the large depth of field compound eye lens 1 shape contour is complete, the central sub-eye 5, the first circle sub-eye 6 and the second circle sub-eye 7 contour is clear; the preparation effect of the large lens 8 and the small lens 9 of each sub-eye is good and the fidelity of the expected design is high;

[0075] As Figure 5 It can be seen that it is the focusing test optical path of the large depth of field micro-artificial compound eye lens 1 prepared in this embodiment;

[0076] Among them, the laser source passes through the compound eye lens 1, enters the CCD through the objective lens 2.

[0077] like Figure 6 It can be seen that the energy distribution diagram of the light spot in the two focusing planes of the micro artificial compound eye lens 1 with a large depth of field;

[0078] By adjusting the relative positions of the objective lens 2, the CCD, and the fly-eye lens 1, the focused light field energy distributions of the two focal planes were captured, indicating that the sub-eyes of the large-depth-of-field micro-artificial fly-eye lens 1 prepared in this embodiment can focus the light spot into two planes;

[0079] Example 3

[0080] By designing a special functional surface shape for the sub-eyes, the limited depth of field of conventional artificial compound eyes is overcome, allowing simultaneous imaging of both near and far objects on the same plane. Fabricating an artificial compound eye lens 1 using femtosecond laser additive manufacturing-assisted shell scanning technology enables imaging with a large depth of field. Ultimately, this is combined with a microscopic observation system 3 to create a micro-bionic artificial compound eye imaging system with a large depth of field.

[0081] This embodiment adopts a method for preparing a micro artificial compound eye imaging system with a large depth of field, and the specific steps are as follows:

[0082] Steps (1), (2), and (3) are the same as those in Example 1.

[0083] (4) Preparation of a micro-artificial compound eye imaging system with large depth of field;

[0084] Specific steps: After completing the preparation of the compound eye lens 1 through femtosecond laser additive manufacturing, a substrate sheet with a thickness of about 140 μm is placed on the edge of the compound eye lens 1 to separate the compound eye from the upper substrate sheet to form a cavity, and deionized water is injected into the cavity to place the compound eye lens 1 in a water environment; then, the lens is placed on a microscope stage to achieve the preparation of a micro artificial compound eye imaging system with a large depth of field through focusing and alignment.

[0085] (5) Image acquisition;

[0086] Specific steps: Place two different masks in different spaces under the bionic artificial compound eye lens 1, namely the letter "f" 10 cm away from the compound eye lens and the number "3" 190 μm away from the compound eye lens, use an illumination light source to illuminate the target object, and then use the combined compound eye imaging system to directly capture the image of the target object.

[0087] like Figure 7 It can be seen that the imaging system test schematic diagram of the large depth of field micro artificial compound eye prepared in this embodiment;

[0088] The imaging system consists of a compound-eye lens 1, an objective lens 2, and a microscopic observation system 3. Objective lens 2 is a 20x objective lens, and microscopic observation system 3 is composed of a domestically produced high-definition CCD and a computer. Simultaneously, the image can be observed on the computer by illuminating the mask with a light source.

[0089] like Figure 8 It can be seen that the large depth of field micro artificial compound eye imaging system can image near and far objects;

[0090] The left picture shows the imaging result of the number "3" at a distance of 190 μm by the large-depth-of-field micro-artificial compound-eye lens 1 prepared by the present invention, and the right picture shows the imaging result of the letter "f" at a distance of 10 cm by the compound-eye lens 1.

[0091] like Figure 9 It can be seen that the imaging results of different space objects by the large depth of field micro artificial compound eye imaging system;

[0092] Traditional uniform compound eye lenses cannot simultaneously receive images of objects at different distances on the same plane; the large depth of field micro artificial compound eye imaging system prepared by the present invention can simultaneously capture images of two objects in different planes.

[0093] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0094] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0095] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A micro artificial compound eye imaging system with a large depth of field, characterized in that: The invention comprises a compound eye lens (1), an objective lens (2) and a microscopic observation system (3); wherein the objective lens (2) is located behind the compound eye lens (1) and aligned with the center line of the compound eye lens (1); and the microscopic observation system (3) is located behind the objective lens (2) to receive imaging information; the compound eye lens (1) comprises a spherical crown base (4), a central sub-eye (5), a first circle eye (6) and a second circle eye (7); the central sub-eye (5) is located at the vertex of the spherical crown base (4), and the first circle eye (6) and the second circle eye (7) surround the first circle and the second circle of the central sub-eye (5); wherein the central sub-eye (5), the first circle eye (6) and the second circle eye (7) are all composite lens structures composed of a large lens (8) and a small lens (9); the small lens (9) is located above the large lens (8); the central sub-eye (5), the first circle eye (6) and the second circle eye (7) are all located on the surface of the spherical crown base (4), and the center line angles of adjacent sub-eyes are all The field of view of the compound eye lens (1) is The focal lengths of the large lens (8) and the small lens (9) vary with the angles between the center lines of the sub-eyes in which they are located and the center line of the central sub-eye (5); The focal lengths of the large lenses (8) in the first circle eye (6) and the second circle eye (7) are L2 and L3 respectively, which are calculated by the following formula: Where L1 is the focal length of the large lens (8) in the central eye (5), R o is the radius of the sphere where the spherical cap base (4) is located, is the field of view of the compound eye lens (1), is the angle between the center lines of adjacent sub-eyes; The focal lengths of the small lenses (9) in the central sub-eye (5), the first circle eye (6) and the second circle eye (7) are l1, l2 and l3 respectively, which are calculated using the convex lens imaging formula: Among them, W min is the minimum object distance.

2. The micro artificial compound eye imaging system with a large depth of field according to claim 1, characterized in that: L1 is 675.00-800.00μm, field of view The range is 100°-110°; the minimum object distance is W min The range is 150-675μm.

3. The micro artificial compound eye imaging system with a large depth of field according to claim 1, characterized in that: The central eye (5), the first circle eye (6) and the second circle eye (7) are closely arranged on the spherical cap base (4); the radius of the central eye (5) is The spherical centers of the large lens (8) and the small lens (9) of the central sub-eye (5), the first circle eye (6) and the second circle eye (7) are respectively on the center line of the respective sub-eyes and the distance between the spherical centers ranges from 90 to 130 μm.

4. The method for preparing a micro artificial compound eye imaging system with a large depth of field according to claim 1, wherein: The specific steps are as follows: Step 1: Sample preparation; Specific steps: First, drop the optical resin on the substrate; place the substrate on a hot table for heating and pre-baking, and then cool it naturally at room temperature; Step 2: Leveling the processing system; The specific steps are as follows: Place the prepared substrate in the galvanometer-based femtosecond laser direct writing processing system, adjust the laser energy to a reference value, focus the laser on the interface between the polymer film formed after pre-baking the optical resin and the substrate, and rotate the stage support screws to ensure that the spot energy remains unchanged when moving left and right and forward and backward. At this point, the stage is considered to be leveled; then, control the laser focus to the interface between the optical resin and the substrate and focus it deep into the substrate. Step 3: Preparation of a micro artificial compound eye with a large depth of field and integration of the imaging system; The specific steps are as follows: generating the point cloud data of the designed micro compound eye lens (1) into a file to be processed; The laser processing power is set and point-by-point scanning processing is performed; the scanned substrate is developed, dried and ultraviolet-exposed, and finally a large-depth-of-field micro-curved artificial compound-eye lens (1) is prepared; finally, the compound-eye lens (1) is sealed and aligned with the microscopic observation system (3) to complete the integration of the imaging system.

5. The method for preparing a micro artificial compound eye imaging system with a large depth of field according to claim 4, characterized in that: In step 1, the optical resin is a variety of ultraviolet optical resins that can be prepared by femtosecond laser two-photon polymerization, including: epoxy resin SU-8, organic / inorganic hybrid photoresist IP-DIP, SZ2080, ultraviolet optical curing glue NOA61, NOA63; the substrate is placed on a hot table for pre-heating, the drying temperature is 50-150°C, and the drying time is 5-30 minutes; to avoid photoresist exposure failure, the photoresist dripping and heating process are both carried out under a yellow light environment; the photoresist liquid collection tool is a rubber-tipped dropper, and the liquid collection dosage is 1 drop; a constant temperature heating table is used to heat the substrate; the substrate pre-baking heating temperature is 90-120°C, and the heating time is 90-120 minutes; the substrate size is 24*24*0.14mm; after pre-baking, it is naturally cooled at room temperature.

6. The method for preparing a micro artificial compound eye imaging system with a large depth of field according to claim 4, characterized in that: In step 2, the galvanometer-based femtosecond laser direct writing processing system includes a fiber femtosecond laser oscillator, an attenuator, an optical gate, a reflector, a beam expansion system, a scanning galvanometer, a 4F optical system and an oil-immersion objective lens; the femtosecond pulse laser generated by the femtosecond laser oscillator passes through the attenuator and the optical gate, passes through the reflector and then passes through the beam expansion system, the beam expanded laser beam controls the beam deflection angle through the scanning galvanometer, and then the laser beam is projected onto the entrance pupil of the objective lens by the 4F optical system, and the beam is focused into the processing sample through the oil-immersion objective lens, and combined with the movement of the translation stage to achieve three-dimensional scanning; at the same time, a real-time monitoring system composed of an illumination light source, a filter, and an imaging CCD is used to observe the status of the sample during processing in real time; The femtosecond laser center wavelength of the galvanometer-based femtosecond laser direct writing processing system is 780nm, the pulse width is 80-180fs, and the repetition frequency is 85-100MHz; the attenuator is a gradient density filter with an operating wavelength of 400-1100nm; the reflector is a dielectric film reflector with an operating wavelength of 800nm; the lens of the 4F optical system is a K9 glass plano-convex lens with a focal length of 100-300mm.

7. The method for preparing a micro artificial compound eye imaging system with a large depth of field according to claim 4, characterized in that: In step 3, the laser processing power is 15-30mw, and the single-point exposure time is 200-1000μs; after the laser processing is completed, the substrate is removed and then placed obliquely in a beaker with the photoresist side facing down, and n-propanol is poured along the wall of the beaker to cover the photoresist for development; the photoresist development time is 10-90min; the ultraviolet lamp used for ultraviolet exposure has a wavelength of 300-450nm, a power of 1-10W, and an exposure time of 5-60min; all the above operations are performed under a yellow light environment; In step three, a cavity is sealed on the substrate and water is injected to place the compound eye lens (1) in a water environment. The microscopic observation system (3) is then aligned with the compound eye lens (1) to complete the combination of the compound eye imaging system.

8. The application of a micro artificial compound eye imaging system with a large depth of field in space image detection as claimed in claim 1, characterized in that: Specifically, the micro artificial compound eye imaging system is used to perform real-time observation of objects at different distances in space.

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