A photofluidic multifocal fluidic microlens array chip and its fabrication method

Abstract

This invention discloses an optofluidic multifocal fluid microlens array chip and its fabrication method. The chip includes a laminar flow control module, a flow mixing module, and a microlens array module. The laminar flow control module includes a set of liquid material sample inlets and a tree-shaped microchannel, which are connected. Liquid materials with different refractive indices and mutual solubility flow into the tree-shaped microchannel from different liquid material sample inlets. The flow mixing module includes a Z-shaped microchannel, one end of which is connected to the tree-shaped microchannel, and the other end is connected to the microlens array channel. The microlens array module includes a set of three-dimensional plano-convex lenses and a sample outlet. The lenses are connected by microchannels to form a microlens array channel structure. One end of the microlens array channel is connected to the Z-shaped microchannel, and the other end is connected to the sample outlet. A multifocal fluid microlens array can be formed, enabling real-time adjustment of the focal length.

Description

Technical Field

[0001] This invention relates to the field of 3D imaging technology, and in particular to an optically fluidized multifocal fluid microlens array chip and its fabrication method. Background Technology

[0002] Currently, 3D imaging technology is a technology capable of capturing and displaying the three-dimensional information of objects. Compared with traditional 2D imaging, 3D imaging can provide a richer visual experience because it can present the depth, height, and width information of objects. Common 3D imaging technologies such as light field imaging, stereo vision technology, and multi-view imaging are widely used in medical imaging, industrial inspection, robot navigation, and other fields. Due to its complete parallax and continuous viewpoints, and the fact that it does not require any observation glasses or special lighting, integrated imaging based on microlens arrays has gradually become the most promising 3D imaging technology, and the development of microlens arrays is key to this.

[0003] Microlens arrays are arrays formed by arranging tiny lenses with optical paths ranging from a few micrometers to a few millimeters on a substrate in a specific pattern. They offer advantages such as high integration and low optical loss, and exhibit optical characteristics such as a large field of view and low phase aberration due to their short effective focal length and high lens curvature. In 3D imaging, each individual microlens images an object from a specific direction, forming an independent sub-image on the image plane. Through this multi-viewpoint imaging, the horizontal and depth information of the 3D object is recorded in the image sensor, completing the acquisition of image information. Then, based on the principle of optical path reversibility, algorithms are used to reconstruct the 3D image of the original object. Currently, there are two main types of fabrication methods for microlens arrays: one is to directly print or engrave the microlens array on the substrate using methods such as electrothermal film imprinting, inkjet printing, hydrodynamic inkjet printing, self-assembly, resist thermal reflow, and laser technology; the other is to use methods such as wet etching and soft lithography to form a mold with a concave 3D microstructure, and then fabricate the microlens array through molding. However, the microlens arrays obtained by these methods have a single focal length, which leads to problems such as narrow depth of field and poor depth perception in 3D imaging applications.

[0004] For example, Chinese patent CN205483948U discloses an optical fluid control chip with two-phase flow and total internal reflection, which includes an optical detection microchannel and microfluidic inlets and microfluidic outlets located at both ends of the optical detection microchannel; the microfluidic inlets include a sample particle inlet, a sheath 1 inlet, and a sheath 2 inlet; the sheath 1 inlet and the sheath 2 inlet are symmetrically distributed on both sides of the sample particle inlet; an optical fiber groove inclined towards the optical detection microchannel is provided next to the microfluidic outlet, and a collimating concave lens is provided between the optical fiber groove and the optical detection microchannel; its microlens array has a single focal length.

[0005] Optofluidics is a rapidly developing emerging technology in recent years. It is an effective means of combining modern optics and microfluidics to study the interaction between light and fluids or endogenous biochemical samples in fluids, and to explore new phenomena, mechanisms, and applications. It has advantages such as high sensitivity, high precision, high integration, and ease of modulation. In recent years, microlens arrays have received widespread attention in optofluidics, especially for real-time control of light field imaging. However, the design and fabrication of fluid-based microlens arrays in optofluidics still face significant challenges and difficulties, particularly regarding the multifocal length and real-time control of microlens arrays. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an optofluidic multifocal fluid microlens array chip and its fabrication method, aiming to achieve real-time adjustability and ease of operation of the multifocal microlens array.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A photofluidic multifocal fluid microlens array chip includes a laminar fluid flow control module, a fluid flow mixing module, and a microlens array module.

[0009] The laminar flow control module includes a set of liquid material sample inlets and a tree-shaped microchannel. The liquid material sample inlets and the tree-shaped microchannel are connected. Liquid materials with different refractive indices and that are miscible flow into the tree-shaped microchannel from different liquid material sample inlets.

[0010] The fluid mixing module includes a zigzag microchannel, one end of which is connected to a tree-shaped microchannel, and the other end of which is connected to a microlens array channel.

[0011] The microlens array module includes a set of three-dimensional plano-convex lenses and a sample outlet. The lenses are connected by microchannels to form a microlens array channel structure. One end of the microlens array channel is connected to a Z-shaped microchannel, and the other end of the microlens array channel is connected to the sample outlet.

[0012] Further:

[0013] The device includes an optofluidic chip, on which a set of liquid material sample inlets, tree-shaped microchannels, Z-shaped microchannels, microlens array channels, and sample outlets are all integrated.

[0014] The individual lenses in the microlens array channel structure are three-dimensional plano-convex lenses, and all microlenses have the same size.

[0015] The microstructure in the optofluidic chip includes two heights: the heights of the sample inlet, sample outlet, tree-shaped microchannel, and zigzag microchannel are smaller than the heights of the microlens array channels.

[0016] Both the sample inlet and the sample outlet are circular channels.

[0017] The tree-shaped microchannel is a channel structure composed of rectangular microchannels.

[0018] The optofluidic chip is made using 3D printing technology, and its manufacturing process differs from that of traditional photolithography.

[0019] It also includes a glass slide, on which the optical fluidic chip is fixed.

[0020] The manufacturing process of the optofluidic chip is as follows: First, the structural mold of the chip is directly printed using 3D printing technology, and then the optofluidic chip is formed by polydimethylsiloxane casting.

[0021] A method for fabricating a multifocal fluid microlens array using the aforementioned optofluidic multifocal fluid microlens array chip includes the following steps:

[0022] S1. Select and prepare liquid materials, including two liquid materials with different refractive indices that are miscible;

[0023] S2. The sample is pushed into the microfluidic channel by a microfluidic pump; two liquid materials are introduced into a set of sample inlets as needed; the two liquid materials form a liquid flow with a gradually changing refractive index and adjustable in real time at the tree-shaped microchannel; the aqueous liquid flow forms a branch with a uniform refractive index through the zigzag microchannel; the branches with different refractive indices flow through the microlens array channel to form a series of fluid microlens arrays with different refractive indices;

[0024] S3. Place the fluid microlens array in a micro-optical platform and measure its focal length and imaging characteristics in real time.

[0025] S4. Through data analysis and feedback, the flow rate ratio of the liquid material is adjusted in real time, and the optical characteristics of the fluid microlens array are further adjusted to obtain a multi-focal length and real-time adjustable fluid microlens array.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] This 3D-printed photofluidic multifocal fluid microlens array chip is rationally designed. By controlling the flow rate of the liquid material, it forms a liquid flow branch with a gradient distribution of refractive index after flowing through the tree-shaped microchannel, thus forming a multifocal fluid microlens array. This enables real-time adjustment of the focal length, is easy to operate, and has a simple structure, making it easy to implement and relatively low in cost. Attached Figure Description

[0028] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings:

[0029] Figure 1 This is a schematic diagram of the optical fluid control chip structure of the present invention.

[0030] Figure 2 This is a diagram showing the generation of the 3D-printed optofluidic chip mold for this invention.

[0031] Figure 3 This is a micrograph of the fluid flow distribution in the optofluidic chip of the present invention.

[0032] Figure 4 This is a micrograph of the focal distribution of the multifocal fluid microlens array of the present invention.

[0033] Figure 5 This is an imaging micrograph of the multifocal fluid microlens array of the present invention.

[0034] In the picture:

[0035] 1-Optical fluid control chip, 2-Liquid material sample inlet I, 3-Liquid material sample inlet II, 4-Liquid material sample inlet III, 5-Dendrical microchannel, 6-Z-shaped microchannel, 7-Microlens array channel, 8-Sample outlet. Detailed Implementation

[0036] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and through the description of the examples.

[0037] like Figures 1 to 5 As shown, the 3D-printed optical fluidic multifocal fluid microlens array chip includes a glass slide, an optical fluidic chip 1, a laminar flow control module, a flow mixing module, and a microlens array module; the laminar flow control module, the flow mixing module, and the microlens array module are all integrated on the optical fluidic chip, which is fixed on the glass slide.

[0038] The laminar flow control module includes three liquid material sample inlets and a tree-shaped microchannel 5. The three liquid sample inlets are liquid material sample inlet I2, liquid material sample inlet II3 and liquid material sample inlet III4 arranged side by side. Two liquid materials with different refractive indices and which are miscible are introduced into the three sample inlets respectively, and flow from the sample inlets into the tree-shaped microchannel 5 to form a set of adjustable liquid flow branches with gradually changing refractive index.

[0039] The fluid mixing module includes a zigzag microchannel 6; one end of the zigzag microchannel is connected to a tree-shaped microchannel, and the other end of the zigzag microchannel is connected to a microlens array channel 7; each fluid branch with a gradually changing refractive index flows through the zigzag microchannel to form a fluid branch with a uniform refractive index.

[0040] The microlens array module includes a sample outlet 8 and a set of three-dimensional plano-convex lenses with the same radius of curvature. The lenses are connected by two-dimensional microchannels to form a microlens array channel 7 structure. One end of the microlens array channel is connected to a Z-shaped microchannel, and the other end of the microlens array channel is connected to the sample outlet.

[0041] like Figure 1 As shown, the three liquid material sample inlets, the tree-shaped microchannel, the zigzag microchannel, the microlens array channel, and the sample outlet are all integrated on the optical fluid control chip 1, forming an integral optical fluid control chip 1 structure. The structure is simple and easy to operate; the tree-shaped microchannel, the zigzag microchannel, and the microlens array channel are connected in sequence.

[0042] Furthermore, the microstructure in the optofluidic chip includes two heights: the sample inlet, sample outlet, tree-shaped microchannel, and zigzag microchannel have heights smaller than the microlens array channel; the sample inlet and outlet, tree-shaped microchannel, and zigzag microchannel have heights of 50 μm, and the microlens array channel has a height of 230 μm.

[0043] The individual lenses in the microlens array channel structure are three-dimensional plano-convex lenses, and all microlenses have the same dimensions; specifically, all microlenses in the microlens array channel have the same size and radius of curvature, with the thickness of an individual microlens being 230 μm and the radius of curvature being 180 μm; the microchannels used to connect the microlenses have a height of 50 μm and a width of 50 μm.

[0044] Both the sample inlet and the sample outlet are circular channels; specifically, both the sample inlet and the sample outlet are 800μm circular channels; one end of the sample inlet is connected to a microchannel with a width of 50μm, and the other end is connected to a microfluidic pump.

[0045] The tree-shaped microchannel is a channel structure composed of rectangular microchannels; specifically, the width of both the tree-shaped microchannel and the zigzag microchannel is 50μm; the tree-shaped microchannel is composed of rectangular microchannels.

[0046] The fabrication of photofluidic chips differs from traditional ultraviolet lithography; it utilizes 3D printing technology. Specifically, the fabrication process is based on two-photon 3D printing technology, using a printing precision of 700nm to directly print the chip's structural mold. After further processing, the chip is formed by casting with polydimethylsiloxane (PDMS).

[0047] This invention creates liquid streams with different refractive indices by controlling the flow rates of two liquid streams with different refractive indices; the different liquid stream streams flow into different microlens array channels to form fluid microlens arrays with different refractive indices.

[0048] By controlling the flow rate of the liquid through real-time data feedback, a suitable refractive index liquid flow distribution is obtained, forming a fluid microlens array, achieving multi-focal length and real-time adjustability. This chip has a simple structure, enables real-time and precise control of the multi-focal length microlens array, and is easy to operate.

[0049] A preferred embodiment of the present invention is as follows:

[0050] like Figure 1 As shown, the 3D-printed optofluidic multifocal fluid microlens array chip is as follows:

[0051] In this embodiment, the optofluidic chip 1 is fabricated using 3D printing technology. The fabrication method is as follows: A three-dimensional chip shape with a 50μm high two-dimensional microchannel structure and a 230μm high three-dimensional microlens array channel is drawn using software. Based on this shape, a three-dimensional mold of the optofluidic chip is fabricated using two-photon 3D printing technology with a printing precision of 700nm. (See...) Figure 2 Further, using the organic material polydimethylsiloxane (PDMS) for casting, followed by heating, curing, casting and fabrication, the final optical fluid chip 1 is obtained;

[0052] The laminar flow control module includes liquid material sample inlet I2, liquid material sample inlet II3, liquid material sample inlet III4, and a tree-shaped microchannel 5. The tree-shaped microchannel is composed of rectangular microchannels. The three sample inlets are connected to the tree-shaped microchannel 5 via an optically controlled microchannel. Two miscible liquid materials with different refractive indices are introduced into sample inlets I2, II3, and III4 respectively, forming a low-high-low refractive index distribution at the three sample inlets. The liquid materials then enter the tree-shaped microchannel 5. By controlling the flow rate of the liquid materials at the three inlets, a set of liquid flow branches with gradually changing refractive index distribution and real-time adjustable flow is obtained. (See: Flowing from the sample inlets into the tree-shaped microchannel 5, forming a set of adjustable liquid flow branches with gradually changing refractive index distribution). Figure 3 (as shown); wherein the liquid material includes an anhydrous alcohol solution with a low refractive index (refractive index 1.361) and a benzyl alcohol solution with a high refractive index (refractive index 1.543);

[0053] The fluid mixing module includes a zigzag microchannel 6, with a width and height of 50 μm. One end of the zigzag microchannel is connected to a tree-shaped microchannel, and the other end is connected to a microlens array channel. This is used to uniformly mix the fluid streams with a gradually varying refractive index (see...). Figure 3 (as shown);

[0054] The microlens array module includes a set of three-dimensional plano-convex lenses, each with a thickness of 230 μm and a radius of curvature of 180 μm. Each column of lenses is connected by microchannels with a height and width of 50 μm to form a microlens channel structure. One end of the microlens array channel is connected to a Z-shaped microchannel 6, and the other end is connected to the sample outlet 8.

[0055] The optofluidic chip comprises two heights: a 50 μm sample inlet / outlet, a tree-shaped microchannel, and a Z-shaped microchannel, along with a 230 μm high microlens array channel. Both the sample inlet and outlet are 800 μm circular channels, and the optofluidic microchannel has a width of 50 μm. One end of the sample inlet is connected to the optofluidic microchannel, and the other end is connected to a micropump.

[0056] Furthermore, the chip also includes a glass slide on which the photofluidic chip is fixed.

[0057] This invention utilizes the aforementioned optofluidic multifocal fluid microlens array chip to fabricate a multifocal fluid microlens array, comprising the following steps:

[0058] S1. Prepare two liquid materials, namely anhydrous ethanol solution and benzyl alcohol solution;

[0059] S2. The sample is injected into the photofluidic microchannel using a micropump. The sample inlets for the two liquid materials are as follows: anhydrous ethanol solution is injected into liquid material sample inlet I2 and liquid material sample inlet III4, and benzyl alcohol solution is injected into liquid material sample inlet II3. The total flow rate of the liquid materials is 100 μL / h. By adjusting the flow rate ratio, liquid streams with different refractive indices are obtained, further forming a fluid microlens array with different refractive indices in the microlens array channel (see...). Figure 3 (As shown).

[0060] S3. Place the fluid microlens array on a microscopic optical platform, change the flow rate ratio of the liquid material, and measure its focal length characteristics in real time (see...). Figure 4 (as shown);

[0061] S4. Through data analysis and feedback, the flow rate ratio of the liquid material is adjusted in real time to further control the optical and imaging properties of the fluid microlens array (see...). Figure 5 As shown in the figure, a multi-focal length and real-time adjustable fluid microlens array is obtained.

[0062] In summary, this invention proposes a 3D-printed optofluidic multifocal fluid microlens array chip. A micropump delivers the sample from the sample inlet to the optofluidic microchannel. Liquid material flows through a tree-shaped microchannel to form a gradually varying refractive index distribution, then through a zigzag microchannel to form a group of uniform liquid streams with different refractive indices, before being injected into the microlens array channel to form a fluid microlens array. By changing the flow rate ratio of the liquid material, fluid microlens arrays with different refractive index distributions are obtained. Using a microscopic optical platform, the optical and imaging characteristics of the fluid microlens array are measured in real time. Furthermore, through data feedback, the flow rate ratio of the liquid material is adjusted to change the optical characteristics of the fluid microlens array in real time, thereby achieving multifocal lengths of the microlens array that are adjustable in real time.

[0063] The above description is merely an illustration of preferred embodiments of the present invention, and the above technical features can be arbitrarily combined to form multiple embodiments of the present invention.

[0064] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the concept and technical solution of the present invention, or the direct application of the concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A photofluidic multifocal fluid microlens array chip, characterized in that: include: The laminar flow control module includes a set of liquid material sample inlets and a tree-shaped microchannel. The liquid material sample inlets and the tree-shaped microchannel are connected. Liquid materials with different refractive indices and which are miscible flow into the tree-shaped microchannel from different liquid material sample inlets. The fluid mixing module includes a zigzag microchannel, one end of which is connected to a tree-shaped microchannel, and the other end of which is connected to a microlens array channel. The microlens array module includes a set of three-dimensional plano-convex lenses and a sample outlet. The lenses are connected by microchannels to form a microlens array channel structure. One end of the microlens array channel is connected to a Z-shaped microchannel, and the other end of the microlens array channel is connected to the sample outlet. A set of liquid material sample inlets, tree-shaped microchannels, Z-shaped microchannels, microlens array channels, and sample outlets are all integrated on the optofluidic chip; Two liquid materials are introduced into a set of sample inlets as needed; the two liquid materials form a liquid flow with a gradually changing refractive index and adjustable in real time at the tree-shaped microchannel; the aqueous liquid flow forms a branch with a uniform refractive index through the zigzag microchannel; the branches with different refractive indices flow through the microlens array channel to form a series of fluid microlens arrays with different refractive indices.

2. The optofluidic multifocal fluid microlens array chip as described in claim 1, characterized in that: The individual lenses in the microlens array channel structure are three-dimensional plano-convex lenses, and all microlenses have the same size.

3. The optofluidic multifocal fluid microlens array chip as described in claim 1, characterized in that: The heights of the sample inlet, sample outlet, tree-shaped microchannel, and zigzag microchannel are less than the height of the microlens array channel.

4. The optofluidic multifocal fluid microlens array chip as described in claim 1, characterized in that: Both the sample inlet and the sample outlet are circular channels.

5. The optofluidic multifocal fluid microlens array chip as described in claim 1, characterized in that: The tree-shaped microchannel is a channel structure composed of rectangular microchannels.

6. The optofluidic multifocal fluid microlens array chip as described in claim 1, characterized in that: The chip is made using 3D printing technology, and its manufacturing process differs from that of traditional photolithography.

7. The optofluidic multifocal fluid microlens array chip as described in claim 1, characterized in that: It also includes a glass slide on which the chip is fixed.

8. The optofluidic multifocal fluid microlens array chip as described in claim 6, characterized in that: The chip manufacturing process is as follows: First, the chip structure mold is directly printed using 3D printing technology, and then polydimethylsiloxane is used to form an optofluidic chip.

9. A method for fabricating a multifocal fluid microlens array using the photofluidic multifocal fluid microlens array chip as described in any one of claims 1 to 8, characterized in that: Includes the following steps: S1. Select and prepare liquid materials, including two liquid materials with different refractive indices that are miscible; S2. The sample is pushed into the microfluidic channel by a microfluidic pump; two liquid materials are introduced into a set of sample inlets as needed; the two liquid materials form a liquid flow with a gradually changing refractive index and adjustable in real time at the tree-shaped microchannel; the aqueous liquid flow forms a branch with a uniform refractive index through the zigzag microchannel; the branches with different refractive indices flow through the microlens array channel to form a series of fluid microlens arrays with different refractive indices; S3. Place the fluid microlens array in a micro-optical platform and measure its focal length and imaging characteristics in real time. S4. Through data analysis and feedback, the flow rate ratio of the liquid material is adjusted in real time, and the optical characteristics of the fluid microlens array are further adjusted to obtain a multi-focal length and real-time adjustable fluid microlens array.

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