玻璃透镜镀膜的基本知识
大家知道，任何物体对光线都有反射作用，这也是我们能看到东西的原因。对于镜片而言，为了使得光线能够完全透过镜头，在底片上完全反映自然的真实情况，镜头尽量是各种光线完全穿过。优质的光学玻璃，其光线透过率可达到90%以上，
尚余的光损失就需要在透镜表面镀上膜来弥补。所以，在光学玻璃透镜上主要是镀减反射膜也叫增透膜。为了满足各种要求，往往需要镀多层膜。为了提高玻璃透镜的抗划伤能力，外面的一层往往是高硬度的膜。在实验室里，现代的工艺技术几乎可以达到光线百分之百通过。之所以这么说，是因为在实际使用中，透镜上会或多或少地受灰尘、脏物等的影响，使得透过镜头的光线减少。镀膜的方法很多，但常规的方法也就那么几种。
(一)、化学方法，包括溶胶—凝胶法、化学气相沉积等方法。根据膜的性质配制一定成分的溶液，然后：
1、浸镀。把洁净的玻璃加热到一定温度，然后放入配置好的化学溶液里，拿出，烘干。这种膜显然是双面膜。
2、喷镀。把配置好的膜溶液装在喷枪上，喷到洁净的、热的玻璃表面。烘干。玻璃体可以是移动或旋转，以增加膜的均匀性。可镀双面或单面。 (以前镜头镀膜有采用所谓的甩胶法，但由于不经济，现代工艺镀无机膜时已将其淘汰，但它仍然是镀有机膜的一种常用、成本低廉的方法)。
以上是玻璃透镜镀膜常用的方法，随着LED照明广泛的发展，对玻璃透镜的要求也越来越高，越来越多的公司要求给玻璃透镜镀膜，来增强透镜的实用性。
光学玻璃透镜的生产流程
近年来由于科技的发展与进步，光学玻璃透镜的制造过程，从熔融原料到押胚成型，多采用自动化生产方式的一贯作业，以提高品质及生产量而降低成本。光学玻璃制造厂商通常着重于开发新产品、生产技术及效率的提升、品质的改善以及制造成本的降低等等，而不扩张生产设备。因此，从接单到出货，往往费时数月。光学玻璃的制造程式大约如下:
一、制造熔解炉：熔解炉有黏土炉及白金炉两种。近年来，渗入稀有元素的光学玻璃都使用小型白金炉，以维持品质的稳定。
二、放入光学玻璃原材料：熔解炉（尤其是黏土炉）经过长时间的干燥后，放入按照特殊配方以及经过选别的原材料于熔解炉中，准备熔融。
三、加热、熔解、搅拌：加热条件，视材质而定。但是，各种材质务必搅拌均匀，以求均质。
四、冷却：长时间予以「徐冷」。但是，时间的长短也因材质而异，这是能保证优良品质的最重要的过程。
五、劈炉、选别：劈开黏土炉（注四），取出块状粗胚并且选别它。
六、检查、测试、整型：逐项检查或测试其各项性能，确保优良品质。
七、切断、倒角（修边）：将块状粗胚按照用途及规格，予以切断成小块并且倒角。
八、押胚成型：将粗胚加热软化后，按照工程图的各项规格，押胚成型。但是，要事先制造或准备各种模具、工具及副料等。
九、烧钝：退火钝化，消除内部应力。
十、测试、检查：测试押胚的光学性能及外观。该成品将成为下游工业（光学元件制造加工厂）的毛胚，继续加工研磨后，成为光学元件。
Basic Knowledge of Coating for Glass Lenses
As we all know, all objects reflect light, which is why we can see them. For lenses, to allow light to pass completely through and accurately reflect the natural scene onto film or sensors, it is ideal for lenses to let as much light as possible pass through. High-quality optical glass can achieve a light transmittance of over 90%. The remaining light loss is addressed by applying coatings to the lens surface.
On optical glass lenses, anti-reflective coatings, also known as anti-glare coatings, are primarily applied. To meet different requirements, multiple layers of coatings are often used. To improve scratch resistance, the outermost layer is typically a high-hardness coating.
In laboratories, modern technology can achieve nearly 100% light transmission. However, in practical applications, lenses are often affected by dust, dirt, and other contaminants, which reduce the amount of light passing through the lens.
There are many coating methods, but only a few are commonly used in the industry. These methods are designed to enhance lens performance and meet the diverse needs of various applications.
(1) Chemical Methods
Chemical methods for coating include the sol-gel method and chemical vapor deposition (CVD). These techniques involve preparing a solution with specific components based on the desired properties of the coating. The process generally includes the following steps:
1. Dip Coating:
Clean the glass thoroughly and heat it to a specific temperature.
Immerse the heated glass into the prepared chemical solution.
Remove the glass and allow it to dry.
This method typically results in a double-sided coating on the glass surface.
2. Spray Coating
• The prepared coating solution is loaded into a spray gun and sprayed onto the clean, heated surface of the glass.
• After spraying, the glass is dried.
• To improve the uniformity of the coating, the glass can be rotated or moved during the process.
• This method allows for coatings on one or both sides of the glass.
(Note: In the past, the "spin-coating method" was used for lens coating, but it has been replaced in modern processes for inorganic coatings due to inefficiency. However, it remains a common and cost-effective method for organic coatings.)
With the widespread development of LED lighting, the demand for coated glass lenses is increasing. Many companies now require coatings on glass lenses to enhance their practicality and performance.
Production Process of Optical Glass Lenses
In recent years, advancements in technology have revolutionized the manufacturing process of optical glass lenses. From melting raw materials to press molding, automation has been widely adopted to improve quality and production efficiency while reducing costs. Optical glass manufacturers focus on developing new products, enhancing production techniques, improving quality, and reducing manufacturing costs, rather than expanding production facilities. As a result, the lead time from order to shipment often takes several months.
Typical Manufacturing Steps for Optical Glass:
1. Furnace Construction:
Furnaces are categorized as clay furnaces or platinum furnaces.
In recent years, rare-element-doped optical glass is manufactured in small platinum furnaces to maintain stable quality.
2. Loading Raw Materials:
After prolonged drying, the selected raw materials, based on specific formulations, are loaded into the furnace for melting.
3. Heating, Melting, and Stirring:
Heating conditions depend on the material.
Uniform stirring is essential to ensure homogeneity across different materials.
4. Cooling:
The molten material undergoes prolonged annealing to cool gradually.
Cooling time varies depending on the material and is critical for ensuring high-quality output.
5. Furnace Opening and Sorting:
The furnace is opened, and solidified glass chunks are extracted and sorted.
6. Inspection and Testing:
Various properties of the glass are inspected and tested to ensure quality.
7. Cutting and Chamfering:
The glass chunks are cut into smaller pieces according to the required specifications and chamfered for refinement.
8. Press Molding:
The glass is heated and softened, then pressed into shapes as per engineering specifications.
Molds, tools, and auxiliary materials must be prepared in advance.
9. Annealing:
The glass undergoes annealing to remove internal stress and stabilize its structure.
10. Final Testing and Inspection:
The pressed blanks are tested for optical performance and appearance.
These blanks are then supplied to downstream industries (such as optical component manufacturers) for further processing, grinding, and polishing into finished optical components.
