What is CR39 lenses

24-05-14 04:46:17    By Bestsea eyewear

 As an eyewear manufacturer, we often use CR39 lenses on frames made of acetate sunglasses, metal sunglasses, horn glasses and other materials. This article talks about what is CR39 lens.


CR-39's scientific name is carbonic acid acrylic acid, or allyl diglycol carbonates (Dially Glycol Carbonates), which is the most widely used material for the production of ordinary resin lenses.

 It was discovered by chemists from Columbia Company in the United States in the 1940s. It is the No. 39 material in a series of polymers developed by the U.S. Air Force. Therefore, it is called CR-39 (Columbia Resin No. 39).
CR39 lenses are made from a plastic material developed by the American company PPG. Its characteristics make it widely used in the spectacle lens manufacturing industry. Lenses made of this material are not only lightweight, but also have excellent impact resistance, which can well protect the eyes from external damage. In addition, CR39 has excellent transparency and refractive index, allowing the wearer to clearly see the surrounding environment. Due to these excellent properties, CR39 lenses are very popular in the glasses manufacturing industry and are widely used in the manufacture of various types of sunglasses, myopia glasses, radiation-proof glasses, and protective glasses.
cr 39 lenses
CR39 lenses are an innovation in modern eyewear technology that incorporates a number of outstanding features. Due to its lightweight nature, this kind of lens can remain comfortable even if worn for a long time, reducing the pressure on the bridge of the nose and ears. It is especially suitable for those who need to wear glasses all day long. In addition, it is extremely impact-resistant and can effectively resist the scratches and impacts that occur in daily use, thus extending the life of the lens. More importantly, CR39 lenses also have a UV protection function, which can protect users’ eyes from harmful UV rays. The comprehensive reflection of these characteristics makes CR39 lenses the first choice for people who pursue high-quality life and eye health.
The production process of CR39 lenses is a delicate and complex process. First of all, choosing high-quality raw materials is the key to producing high-quality lenses. These raw materials mainly include monomers, polymers and cross-linking agents, which together determine the transparency, hardness and wear resistance of the lens. When selecting raw materials, full consideration needs to be given to their chemical and physical properties to ensure the quality and performance of the final product. Next, these raw materials are mixed together to form a homogeneous solution. In this process, temperature and time need to be strictly controlled to ensure that the various ingredients can be fully integrated to form a stable chemical reaction system. This solution is then poured into a mold and gradually shaped into the shape of the lens using heat and pressure. This process requires precise control of temperature and pressure to ensure the dimensional accuracy and surface smoothness of the lenses. Finally, after cooling and demolding, we got the CR39 lens we wanted. Although this process seems simple, it actually involves many chemical reactions and physical changes, requiring a high degree of professional knowledge and technology. Only in this way can we produce CR39 lenses that are both beautiful and practical, bringing consumers a better visual experience.
CR39 lenses have significant differences in weight, durability, light transmittance and other properties compared to lenses made of other materials. Let’s make a comparison of the currently popular lenses made of several materials.
1. Weight. Glass lenses are the heaviest, followed by CR39 lenses, followed by nylon lenses and PC lenses. Compared with glass lenses, the weight of C39 lenses is moderate, which greatly reduces the pressure on the bridge of the nose and ears of the wearer after wearing glasses for a long time, improving the wearing comfort. Glass lenses are rarely used today because they are too heavy.
2. Durability and impact resistance. From the perspective of durability, nylon lenses and PC lenses are the best, followed by CR39 lenses, and glass lenses are more fragile. It has stronger impact resistance and is not easy to break, which is a very important advantage for people who do regular sports or outdoor activities. High-quality CR39 lenses also have very good durability and impact resistance, and must be able to pass the falling ball test. Drop ball lenses are mainly used to test lenses. A steel ball is dropped from a certain height on the convex surface of the lens. The diameter of the steel ball is required to be 0.625 inches and the weight is equivalent to 1 ounce. It is dropped from a height of 50 inches. It is required that the lens cannot be cracked.
3.Light transmittance. The transmittance of a lens indicates the ability of light to pass through the lens medium. . The higher the light transmittance, the better the light transmission effect of the lens. The value of light transmittance is a percentage, and the value range is 0~100%. Among lenses made of various materials, glass lenses have the best light transmittance, which can reach more than 99%, followed by CR39 lenses, nylon lenses, PC lenses and AC lenses. CR39 also has very excellent light transmittance, which can reach more than 95%. High-quality CR39 lenses can reach 99%, such as Zeiss lenses.
4. Function. The additional functions of the lens depend on subsequent processes. For example, UV protection function, coating function, AR anti-reflection function, anti-blue light function, polarizing function, waterproof and oil-proof function, etc., can all be reflected on lenses made of different materials.
5. Application. CR39 lenses are widely used in various eyewear types due to their excellent performance and adaptability. It can be used on glasses made of various materials without causing abnormal chemical reactions, such as plate glasses, metal glasses, titanium glasses, horn glasses and wood glasses, etc. It is widely used in these types of glasses. For myopia glasses, lenses made of this material have become the first choice for many myopia patients due to their excellent optical properties, shatter resistance and comfortable wearing experience. CR39 lenses are even more common among reading glasses, which can help improve near vision and reduce eye fatigue. Especially in the field of sunglasses, regardless of the weight, color, function, etc. of the lenses, they are one of the best choices and the most used lenses. However, because CR39 has very good hardness, it is easier to break when drilling or cutting at a relatively large angle, so it is not suitable for this type of frame, such as frameless, etc. This type of frame must use nylon Lenses, nylon lenses have better toughness.
8.CR39 lenses use a dyeing process. The prepared toner is poured into a customized solution, and the transparent CR39 lens is placed inside until the color penetrates into the lens. Therefore, in theory, the color of CR39 lenses can be any color in the Pantone color card. Below are some of the more common CR39 lens colors.
9.1. Transparent color is the most common CR39 lens color. It is suitable for almost all occasions, whether it is a daily office, study or outdoor activities,and it can provide clear vision. Another advantage of clear lenses is that they are highly matchable and suitable for a variety of frame styles and colors.
10.2.CR39 gray sunglasses. Gray lenses are a popular choice for many consumers. Gray can effectively reduce glare and enhance contrast, making the visual experience clearer and more comfortable. Gray lenses are a great option for those who frequently work in bright light environments. At the same time, gray lenses are also very suitable for driving because they can reduce the interference of reflected light from the road and improve driving safety.
11.3.CR39 brown lenses provide another visual experience. Lenses in these colors enhance contrast and depth perception, especially in low light or cloudy weather conditions. For those who like outdoor sports, lenses of this color can help them better distinguish terrain and obstacles.
12.4. Blue or green lenses are usually used to reduce glare and filter blue light. They are particularly suitable for water sports or snow activities, where strong reflections from water and snow can cause eye irritation. By filtering out part of the blue spectrum, these lenses provide a more comfortable visual experience.
13.5. CR39 yellow lenses, also called night vision lenses, hardly reduce the transmittance of visible light, can absorb most of the blue light, and allow infrared and visible light to pass through. This makes yellow lenses particularly effective in low-light or low-visibility environments such as cloudy days, foggy days, early mornings, and dusk, improving contrast for clearer vision. In addition, yellow lenses can absorb 100% of ultraviolet rays and part of blue light, providing additional protection for the eyes and reducing eye fatigue and discomfort.
14.6. In addition to the above common colors, there are more personalized choices on the market, such as pink, purple, etc. Although these colors are relatively rare in daily life, they still have their own uniqueness. For example, blue spectacle lenses can effectively filter out the damage to the eyes caused by ultraviolet rays, blue light, etc. in daily life, and can effectively relieve visual fatigue. While purple and pink may cater more to specific fashion needs and personal preferences.
15.7. In addition, the surface of CR39 lenses can be coated with various colored films. Common ones include blue film, green film, orange film, pink film, etc. These rich colors make it easier to match glasses with clothing.
When choosing CR39 lenses, you also need to consider your personal skin tone and clothing style. Generally speaking, warm-toned lenses are more suitable for people with yellowish or reddish skin, while cool-toned lenses are more suitable for consumers with fairer skin. Of course, the final choice still depends on personal comfort and aesthetics.
No matter which color of CR39 lenses you choose, it is very important to check your vision and lens condition regularly. Vision may change over time, and lenses may become scratched or discolored from prolonged use. Therefore, regular visits to a professional optical shop for vision tests and lens maintenance will help ensure that your glasses are always in top condition.
Among polarized lenses, CR39 polarized lenses are one of the best polarized lenses. Polarizers are lenses made based on the polarization principle of light. They are used to exclude and filter out direct light in the light beam, so that the light can enter the visual image of the eye on the right transmission axis, making the vision clear and natural. The quality of CR39 polarized lenses mainly depends on the manufacturing process and the polarizing film in the middle. Most of the high-quality polarizing films come from Japan.
In order to extend the life of CR39 lenses and maintain excellent visual effects, proper cleaning and maintenance are key. First, you should use special lens cleaning fluid and a microfiber cloth to wipe. Avoid using corrosive cleaners or rough cloths, which may scratch the lens. Secondly, it is not recommended to expose the lenses to high temperature environments, such as in direct sunlight or near fire sources, because CR39 lenses are easily deformed due to high temperatures. Finally, when your glasses are not in use, it is best to store them in a dedicated glasses case to avoid unnecessary damage to the lenses. In addition, it is also necessary to regularly go to a professional optical shop for lens inspection and adjustment. Due to long-term use, the frame may undergo slight deformation, affecting the position of the lenses and visual effects.
Professional technicians can make adjustments to restore the frame to its original shape, ensuring that the lenses provide the best possible vision. At the same time, it can also be found in time whether the lens is worn or has other problems, so that it can be replaced in time. In general, only through correct cleaning, avoiding high temperatures, proper storage, and regular professional inspections can the clarity and comfort of CR39 lenses be effectively guaranteed, so that our eyes are always in the best visual condition.
In today's eyewear market, CR39 lenses have undoubtedly become a popular choice. This resin material, known for its comfort and lightness, not only meets the basic visual needs of consumers, but is also favored for its excellent impact resistance and high refractive index. However, with the advancement of technology and the diversification of consumer needs, CR39 lenses are facing a series of new challenges and opportunities.
Technological innovation is a key factor driving market development. In order to cater to consumers' demands for high customization, manufacturers are developing more types of personalized CR39 lenses, such as lenses that can adapt to different lighting environments and have intelligent color-changing functions. These innovations not only improve the technological content of products, but also greatly enrich the range of choices for consumers.
At the same time, consumer preferences are also changing quietly. As health awareness increases, more and more people are paying attention to the protective functions of glasses, such as blue light blocking and ultraviolet protection. In addition, the influence of fashion trends cannot be ignored. Consumers are increasingly inclined to choose eyewear products with novel designs and diverse styles, which puts forward higher requirements for the market positioning of CR39 lenses.


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