CN101339364B - Method for manufacturing micro-lens array by soft mould impression - Google Patents

Abstract

A method for manufacturing a micro-lens array by soft mold imprinting is characterized in that a traditional photoresist hot melting method is utilized to manufacture a mother micro-lens array, polydimethylsiloxane is utilized as a micro-lens mold, and an imprinting method is adopted to transfer a micro-lens array pattern onto ultraviolet glue on a glass substrate. The invention has the advantages of simple process, low cost and mass production.

Description

Translated fromChinese

软模压印制造微透镜阵列的方法Method for manufacturing microlens array by soft mold embossing

技术领域technical field

本发明涉及微透镜阵列，特别是一种软模压印制造微透镜阵列的方法。The invention relates to a microlens array, in particular to a method for manufacturing a microlens array by soft mold embossing.

背景技术Background technique

微透镜阵列是一种目前使用十分广泛的微光学元件，它是一系列孔径在几个微米至几百个微米的微小型透镜按一定排列组成的阵列，广泛的应用于光束整形，光学器件互连，光信息处理、三维成像等领域。Microlens array is a kind of micro-optical element that is widely used at present. It is an array composed of a series of tiny lenses with apertures ranging from a few microns to hundreds of microns. It is widely used in beam shaping and optical device interaction. Lian, optical information processing, 3D imaging and other fields.

目前，用于制作微透镜阵列的方法主要有光刻胶热熔法、光敏玻璃法、离子交换法，反应离子刻蚀法。At present, the methods used to fabricate microlens arrays mainly include photoresist hot-melt method, photosensitive glass method, ion exchange method, and reactive ion etching method.

光刻胶热熔法就是以光致抗蚀剂为材料，采用光刻，腐蚀的方法使材料成为一个个圆柱体，然后用烘烤加热的方法，使其溶解，依靠表面张力，冷却后最终成为球冠状的微透镜。该方法的优点是工艺简单，制作容易，成本低。但是光致抗蚀剂本事具有一定的颜色，这种方法制造的微透镜阵列光能损耗大，波长依赖性大，而且材料的熔点较高，需要较高的烘烤温度。The photoresist hot-melt method is to use photoresist as the material, use photolithography and corrosion to make the material into cylinders, and then use baking and heating to dissolve it, rely on surface tension, and finally cool it down. Microlenses that become spherical crowns. The method has the advantages of simple process, easy manufacture and low cost. However, the photoresist itself has a certain color, and the microlens array manufactured by this method has a large loss of light energy, a large wavelength dependence, and a high melting point of the material, which requires a high baking temperature.

光敏玻璃热成型法是用紫外辐射曝光来调制光敏玻璃材料，就是用紫外线通过掩模对其曝光，在将材料加热到软化点，材料发生膨胀。然后对光敏玻璃两侧施加压力，由于光敏玻璃被曝光的部分的密度与硬度远大于未曝光的部分，在挤压过程中未曝光的部分会高出表面，在表面张力的作用下，突出的表面变成球形，从而形成透镜的形状。这种方法的缺点是必须使用特殊的玻璃，且较难改变透镜焦距等参数。The photosensitive glass thermoforming method uses ultraviolet radiation exposure to modulate the photosensitive glass material, that is, exposes it through a mask with ultraviolet rays, and heats the material to the softening point, and the material expands. Then apply pressure to both sides of the photosensitive glass. Since the density and hardness of the exposed part of the photosensitive glass are much greater than that of the unexposed part, the unexposed part will be higher than the surface during the extrusion process. Under the action of surface tension, the protruding The surface becomes spherical, resulting in the shape of a lens. The disadvantage of this method is that special glass must be used, and it is difficult to change parameters such as the focal length of the lens.

离子交换方法就是在高温装有某种熔盐的容器中，金属离子由外及里扩散到玻璃介质中去，并且置换出玻璃介质的一些离子，在玻璃表面附近形成折射率梯度，其性能类似于小透镜。这种方法制作出的微透镜阵列比较坚固。这种方法的缺点是制作周期长，需要高温。The ion exchange method is to diffuse metal ions into the glass medium from the outside to the inside in a container with a certain molten salt at high temperature, and replace some ions in the glass medium, forming a refractive index gradient near the glass surface, and its performance is similar to in the small lens. The microlens array produced by this method is relatively strong. The disadvantage of this method is that the production cycle is long and high temperature is required.

反应离子刻蚀方法首先用光刻胶热熔法在光刻胶上制作微透镜阵列，然后把样品暴露在精确控制的反应离子中，光刻胶和基底材料都受到刻蚀，光刻胶上的微透镜图形被转移到基底材料中，从而在基底上形成微透镜阵列。这种方法的缺点是必须精确控制基底材料和光刻胶的刻蚀速率，工艺较难控制，而且由于光刻胶和基底材料的刻蚀速率不一样，光刻胶图形并不能完全转移到基底中去。The reactive ion etching method first uses the photoresist hot melt method to make a microlens array on the photoresist, and then exposes the sample to precisely controlled reactive ions, the photoresist and the base material are etched, and the photoresist The microlens pattern is transferred to the substrate material, thereby forming a microlens array on the substrate. The disadvantage of this method is that the etching rate of the substrate material and the photoresist must be precisely controlled, the process is difficult to control, and because the etching rate of the photoresist and the substrate material is different, the photoresist pattern cannot be completely transferred to the substrate. to go.

以上所述的各种微透镜阵列制作方法，对于微透镜的小批量制作较为合适，但如果需要大批量生产微透镜阵列，以上方法就不太方便，而且成本高，总的生产过程复杂，产品均匀性难以保证。因此发展低成本、工艺简单、能够大批量生产的微透镜制作工艺非常重要。The various microlens array manufacturing methods described above are more suitable for small-batch production of microlenses, but if microlens arrays need to be produced in large quantities, the above methods are not very convenient, and the cost is high, and the overall production process is complicated. Uniformity is difficult to guarantee. Therefore, it is very important to develop a low-cost, simple process, and capable of mass-production microlens manufacturing process.

发明内容Contents of the invention

本发明是的目的是在于克服上述现有技术的不足，提供一种软模压印制造微透镜阵列的方法，该方法具有工艺简单、成本低、制造周期短和可以大批量生产等优点。The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method for manufacturing a microlens array by soft mold embossing, which has the advantages of simple process, low cost, short manufacturing cycle and mass production.

本发明的技术解决方案如下：Technical solution of the present invention is as follows:

一种软模压印制造微透镜阵列的方法，其特点是该方法利用传统的光刻胶热熔方法制造母微透镜阵列，利用聚二甲基硅氧烷(PDMS)作为微透镜模具，采用压印方法将微透镜阵列图形转移到玻璃基板上的紫外胶上。A method for manufacturing a microlens array by soft mold embossing, which is characterized in that the method utilizes a traditional photoresist hot-melt method to manufacture a mother microlens array, uses polydimethylsiloxane (PDMS) as a microlens mold, and uses embossing The printing method transfers the pattern of the microlens array to the UV glue on the glass substrate.

一种软模压印制造微透镜阵列的方法，包括下列步骤：A method for manufacturing a microlens array by soft mold embossing, comprising the following steps:

①在一基片上旋涂一层光刻胶，将具有微透镜阵列分布的透光板覆盖在所述的光刻胶上，通过光刻的方法在基片上得到阵列分布的圆柱形微结构；① Spin-coating a layer of photoresist on a substrate, covering the light-transmitting plate with microlens array distribution on the photoresist, and obtaining a cylindrical microstructure of array distribution on the substrate by photolithography;

②将所述的基片置于在一平板上加热，使光刻胶的温度达到熔化温度以上并持续一段时间，由于表面张力的作用，每一个圆柱形光刻胶各自收缩成球冠结构；② Place the substrate on a flat plate and heat it so that the temperature of the photoresist reaches above the melting temperature and lasts for a period of time. Due to the effect of surface tension, each cylindrical photoresist shrinks into a spherical cap structure;

③冷却到室温，得到母微透镜阵列基片；③ cooling to room temperature to obtain the mother microlens array substrate;

④将所述的母微透镜阵列基片放入一个塑料培养皿中并使微透镜阵列面朝上，将混合好的聚二甲基硅氧烷，以下简称为PDMS，倒入所述的培养皿中，PDMS薄膜的厚度控制在3～5mm；④ Put the mother microlens array substrate into a plastic petri dish with the microlens array facing up, pour the mixed polydimethylsiloxane, hereinafter referred to as PDMS, into the culture dish In the dish, the thickness of the PDMS film is controlled at 3-5mm;

⑤热固化PDMS薄膜：固化温度在25℃到100℃之间，PDMS薄膜完全固化后，沿着一个方向用镊子从一侧揭起所述的PDMS薄模，使其和母微透镜阵列基片分离，得到一个和原微透镜阵列表面形貌相反的PDMS模具；⑤Heat-curing PDMS film: The curing temperature is between 25°C and 100°C. After the PDMS film is completely cured, use tweezers to lift the PDMS thin film from one side along one direction, so that it and the mother microlens array substrate Separation to obtain a PDMS mold opposite to the surface morphology of the original microlens array;

⑥将玻璃基板置于平台上，在该玻璃基板的表面滴放紫外胶，选用的紫外胶应是一种无色透明的液体，粘滞系数应小于500厘泊，有好的流动性，邵氏硬度D大于70，将所述的PDMS模具朝下垂直轻压在紫外胶的表面，让其在玻璃基板上自然静止5分钟以上，利用所述的PDMS模具本身重力和毛细效应，使所述的紫外胶完全充满PDMS的沟槽；⑥Place the glass substrate on the platform, and drop UV glue on the surface of the glass substrate. The UV glue used should be a colorless and transparent liquid with a viscosity coefficient of less than 500 centipoise and good fluidity. The hardness D is greater than 70. Press the PDMS mold vertically downward on the surface of the UV glue, let it rest naturally on the glass substrate for more than 5 minutes, and use the gravity and capillary effect of the PDMS mold itself to make the The UV glue completely fills the groove of PDMS;

⑦将所述的玻璃基板连同PDMS模具移到紫外灯下，用紫外光下固化所述的紫外胶，移动时放在平台上，不要让两者之间产生位移；固化时间取决于选用的紫外灯能量和光敏聚合物类型与使用量；⑦Move the glass substrate together with the PDMS mold to the UV lamp, cure the UV glue under UV light, and put it on the platform when moving, so as not to cause displacement between the two; the curing time depends on the selected UV glue. Lamp energy and photopolymer type and amount used;

⑧固化完全后沿着一个方向从一侧揭起所述的PDMS模具，使其和紫外胶分离，即在玻璃基板上的紫外胶上形成微透镜阵列图形，获得所需要的玻璃基板微透镜阵列。⑧ After curing is complete, lift the PDMS mold from one side along one direction to separate it from the UV glue, that is, form a microlens array pattern on the UV glue on the glass substrate to obtain the required glass substrate microlens array .

所述的基片是硅或者玻璃制成的。The substrate is made of silicon or glass.

本发明所采用的工艺条件主要特点有以下几点：The technological condition main characteristic that the present invention adopts has the following points:

第一、所用的母微透镜阵列采用传统的光刻胶热熔法制造，整个工艺过程中只需要一次热熔工艺。采用PDMS制作微透镜阵列模具，PDMS比较容易和光刻胶材料分离，制作PDMS模具时工艺容易控制，而且制备PDMS模具时不会对母微透镜阵列产生损坏，母微透镜阵列可以多次使用。First, the mother microlens array used is manufactured by traditional photoresist hot-melt method, and only one hot-melt process is required in the whole process. Using PDMS to make a microlens array mold, PDMS is relatively easy to separate from the photoresist material, the process is easy to control when making a PDMS mold, and the mother microlens array will not be damaged when preparing the PDMS mold, and the mother microlens array can be used multiple times.

第二、微透镜阵列图形通过压印的方法转移到玻璃基板上的紫外胶上，由于紫外胶的折射率和玻璃非常接近，而且无色、透明，具有良好的光学性能，所以制得的微透镜阵列具有非常好的光学性能。这就避免了光刻胶热熔法由于光刻胶颜色引起的光学性能的改变。Second, the pattern of the microlens array is transferred to the UV glue on the glass substrate by embossing. Since the refractive index of the UV glue is very close to that of glass, and it is colorless, transparent, and has good optical properties, the prepared microlens Lens arrays have very good optical properties. This avoids the change of optical properties caused by the color of the photoresist in the photoresist hot-melt method.

第三、采用玻璃作为基底材料，利用紫外胶和玻璃很强的粘着力以及玻璃很高的硬度，便于微透镜阵列的使用。Third, glass is used as the base material, and the strong adhesion between the ultraviolet glue and the glass and the high hardness of the glass are used to facilitate the use of the microlens array.

第四、PDMS模具可以多次使用，使用50次以上不见损坏，具有成本低、可以大批量生产的优点。Fourth, the PDMS mold can be used many times, and no damage can be seen after using it for more than 50 times. It has the advantages of low cost and mass production.

因此，本发明方法具有工艺简单、成本低、制造周期短和可以大批量生产等优点。Therefore, the method of the present invention has the advantages of simple process, low cost, short manufacturing cycle and mass production.

具体实施方式Detailed ways

下面结合实施例对本发明作进一步说明。采用软模压印法制造微透镜阵列，第一步要用光刻胶热熔法制作一个母微透镜阵列。首先在干净的玻璃基片上采用旋涂的方式均匀的涂一层光刻胶(shiplay1818，或者shiplay1805等)；然后通过曝光、显影，在基片上得到圆柱形的微结构；最后在热平板上将基片在130℃时加热10分钟，取下基片，待其冷却后即可得到母微透镜阵列。The present invention will be further described below in conjunction with embodiment. To fabricate microlens arrays by soft mold imprinting, the first step is to fabricate a mother microlens array by hot-melting photoresist. First, evenly coat a layer of photoresist (shipay1818, or shiplay1805, etc.) on a clean glass substrate by spin coating; then obtain a cylindrical microstructure on the substrate through exposure and development; The substrate is heated at 130° C. for 10 minutes, the substrate is removed, and the mother microlens array can be obtained after cooling.

第二步是用压印的方法将微透镜阵列图形转移到紫外胶上。首先要制作一个有机硅橡胶模具：我们利用聚二甲基硅氧烷(PDMS，Sylgard184，Dow Coring)来制作模具，先把主剂和固化剂按照重量比为10：1的比例混合，搅拌均匀，如果产生气泡则需要经过真空脱泡处理，真空脱泡的时间取决于搅拌过程中混入的气泡量；脱泡完成后把PDMS均匀的涂覆在母微透镜阵列的表面，然后室温固化48小时或者高温固化，高温固化可以减少固化时间，我们在25℃下固化48个小时，60℃下固化4小时，90℃下固化90分钟，都可以有好的固化效果。PDMS完全固化后，从一个方向上用镊子揭起PDMS模具，PDMS模具和母微透镜阵列可以很容易地分离。The second step is to transfer the pattern of the microlens array to the UV adhesive by embossing. First of all, we need to make a silicone rubber mold: we use polydimethylsiloxane (PDMS, Sylgard184, Dow Coring) to make the mold, first mix the main agent and curing agent in a weight ratio of 10:1, and stir well , if bubbles are generated, vacuum defoaming treatment is required. The time of vacuum defoaming depends on the amount of bubbles mixed in the stirring process; after defoaming is completed, evenly coat PDMS on the surface of the mother microlens array, and then cure at room temperature for 48 hours Or high temperature curing, high temperature curing can shorten the curing time, we can cure at 25°C for 48 hours, at 60°C for 4 hours, and at 90°C for 90 minutes, all of which can have a good curing effect. After the PDMS is fully cured, lift the PDMS mold with tweezers from one direction, and the PDMS mold and the mother microlens array can be easily separated.

得到PDMS模具后就可以把微透镜阵列图形转移到紫外胶上，我们使用的是低粘度系数的紫外胶NOA61(Norland)，粘度系数为300厘泊，硬度为85，也可使用NOA60、OG146、OG169(Epotek)等。先在干净的玻璃基片上滴一滴NOA61，把PDMS模具垂直压印在NOA61胶的上面，然后室温下静止放置5分钟，这有助于去除压印时产生的气泡，待紫外胶完全填充满模具的空隙后放在70瓦的汞灯下固化，固化时间为20分钟，当NOA61紫外胶完全固化后就可以容易地分离PDMS模具，得到最终的微透镜阵列。After the PDMS mold is obtained, the microlens array pattern can be transferred to the UV adhesive. We use the UV adhesive NOA61 (Norland) with a low viscosity coefficient. The viscosity coefficient is 300 centipoise and the hardness is 85. NOA60, OG146, OG169 (Epotek) and others. First drop a drop of NOA61 on a clean glass substrate, imprint the PDMS mold vertically on the top of the NOA61 glue, and then let it stand at room temperature for 5 minutes, which helps to remove the air bubbles generated during the imprinting, until the UV glue is completely filled with the mold After the gaps are placed under a 70-watt mercury lamp for curing, the curing time is 20 minutes. When the NOA61 UV glue is completely cured, the PDMS mold can be easily separated to obtain the final microlens array.

经过扫描电镜测试制得的微透镜阵列，表明：图形分布均匀，压印复制微透镜阵列的焦距为36μm，和理论计算值基本一致。The prepared microlens array is tested by scanning electron microscope, which shows that the pattern distribution is uniform, and the focal length of the imprinted replication microlens array is 36 μm, which is basically consistent with the theoretical calculation value.

采用软模压印技术制造折射型微透镜阵列有其独特的优点。其一，采用传统的光刻胶热熔方法制作母微透镜阵列；其二，微透镜图像转移过程中不需要高温高压的条件，造价低；其三、紫外胶的折射率和玻璃的折射率非常接近，而且紫外胶和玻璃有很好的粘结性；其四、紫外胶NOA61是一种透明、无色、具有极好透光性的光学粘合剂，避免了光刻胶由于有颜色而引起的吸收和像差；其五、制作周期短，紫外胶的固化时间短，通常几分钟的时间就能固化完全。总之，压印技术制造微透镜阵列具有精度高、工艺简单、造价低、可以大规模制造等优点，在微透镜的制造中有很重要的应用。特别是本发明的利用紫外压印技术转移微透镜阵列图形，充分利用了PDMS模具分辨率高、制作简单和紫外胶有良好的光学性能、固化速度快、折射率和玻璃的折射率接近等优点，可以大批量、低成本的生产。制成的折射型微透镜阵列性能稳定、可靠，是实现微透镜阵列大规模生产的一条重要途径。Manufacturing refractive microlens arrays with soft mold imprinting technology has its unique advantages. First, the traditional photoresist hot-melt method is used to make the mother microlens array; second, the microlens image transfer process does not require high temperature and high pressure conditions, and the cost is low; third, the refractive index of ultraviolet glue and the refractive index of glass It is very close, and the UV glue and glass have good adhesion; Fourth, the UV glue NOA61 is a transparent, colorless, optical adhesive with excellent light transmission, which avoids the photoresist due to color The absorption and aberration caused by it; Fifth, the production cycle is short, and the curing time of ultraviolet glue is short, usually it can be completely cured in a few minutes. In short, the imprinting technology to manufacture microlens arrays has the advantages of high precision, simple process, low cost, and large-scale manufacturing. It has very important applications in the manufacture of microlenses. In particular, the use of UV imprinting technology to transfer microlens array graphics in the present invention fully utilizes the advantages of high resolution of PDMS molds, simple manufacture, good optical properties of UV glue, fast curing speed, and close refractive index to glass. , can be produced in large quantities and at low cost. The manufactured refractive microlens array has stable and reliable performance, and is an important way to realize the mass production of the microlens array.

Claims (3)

1. the method for a manufacturing microlens array by soft mode impressing, it is characterized in that this method utilizes traditional photoresist melt process to make female microlens array plate, with dimethyl silicone polymer, be designated hereinafter simply as PDMS, be coated in the surface of female microlens array plate equably, its heat curing is obtained the PDMS mould, drip the glass substrate that ultraviolet glue is arranged, obtain needed glass substrate microlens array after the curing with the PDMS die marks.

2. the method for manufacturing microlens array by soft mode impressing according to claim 1 is characterized in that comprising the following steps:

1. spin coating one deck photoresist on a substrate will have the light-passing board that microlens array distributes and cover on the described photoresist, obtain the cylindrical shaped microstructures of array distribution on substrate by the method for photoetching;

2. described substrate is placed at one and dull and stereotyped goes up heating, it is above and continue for some time to make the temperature of photoresist reach temperature of fusion, because capillary effect, each cylindrical photoresist is shrunk to spherical cap structure separately;

3. cool to room temperature obtains female microlens array plate;

4. described female microlens array plate is put into a plastic culture dish and made female microlens array surface substrate up, with dimethyl silicone polymer, be designated hereinafter simply as PDMS, pour in the described double dish, the THICKNESS CONTROL of PDMS film is at 3～5mm;

5. heat curing PDMS film: solidification temperature is between 25 ℃ to 100 ℃, after the PDMS film full solidification, uncover described PDMS film with tweezers from a side along a direction, it is separated with female microlens array plate, obtain a PDMS mould opposite with female microlens array plate surface topography;

6. glass substrate is placed on the platform, drip on the surface of this glass substrate and to put ultraviolet glue, the ultraviolet glue of selecting for use should be a kind of water white liquid, the coefficient of viscosity should have good flowability less than 500 centipoises, and shore hardness D is greater than 70, described PDMS mould vertically gently is pressed in the surface of ultraviolet glue down, be allowed to condition on the glass substrate staticly naturally more than 5 minutes, utilize gravity of described PDMS mould own and capillary effect, make described ultraviolet glue be full of the groove of PDMS mould fully;

7. described glass substrate is moved on under the uviol lamp together with the PDMS mould,, be placed on when mobile on the platform, do not allow and produce displacement between the two with the described ultraviolet glue of ultraviolet light polymerization; Depend on the uviol lamp energy selected for use and the use amount of ultraviolet glue set time;

8. uncover described PDMS mould along a direction from a side behind the completion of cure, it is separated with ultraviolet glue, promptly on the ultraviolet glue on the glass substrate, form the microlens array figure, obtain needed glass substrate microlens array.

3. the method for manufacturing microlens array by soft mode impressing according to claim 2 is characterized in that described substrate is that silicon or glass are made.