In the previous article, we discussed “What are acetate sunglasses?”. In this article, let’s talk about “Differences between polarized and photochromic lenses”.
The two principles are different
Color changing lens
A substrate color-changing lens is a chemical substance of silver halide added to the lens substrate. Using the ion reaction of silver halide, it is decomposed into silver and halogen under strong light stimulation, so that the lens is colored, and after the light is weakened, it is combined into silver halide. The color becomes lighter. This kind of technology is often used for glass color lenses.
The film color lens is specially treated in the lens coating process. For example, spiropyran compounds are used for high-speed spin coating on the surface of the lens. According to the intensity of light and ultraviolet rays, the molecular structure itself can be opened and closed to achieve the effect of passing or blocking light.(https://www.koalaeye.com/blogs/our-stories)
A polarized lens is a lens that only allows light in a certain polarization direction in natural light to pass through. Adding a vertical special paint to the lens is called a polarized lens. Polarized lenses allow light to be adjusted to the same direction and enter the glasses, making the scene look soft and not glaring.
The two functions are different
The color-changing lens can be quickly darkened under the irradiation of light and ultraviolet rays, block the strong light and absorb ultraviolet rays, and have a neutral absorption of visible light.
The special effect of the polarized lens is to effectively eliminate and filter out the scattered light in the beam. The light can be injected into the visual image of the eye on the transmission axis of the right track so that the visual field is clear and natural.
The two characteristics are different
Color changing lens
Most of the film discoloration technology is faster than the substrate discoloration technology. The photochromic factor uses spiropyran compounds, which have better light responsiveness, and uses the inverted opening and closing of the molecular structure itself to achieve the effect of passing or blocking light, so faster in changing color speed.
In the traditional base color lens, the photochromic factor is on the lens substrate, and the color change effect will be affected by the thickness of different areas of the lens. Because the center of the lens is thin and the periphery is thick, the center area of the lens discolors more slowly than the periphery, and the panda eye effect will appear. The film-layer color-changing lens uses high-speed spin coating technology, and the color-changing film layer is uniformly spin-coated to make the color more uniform after the color change.
Polarized lenses can filter out a lot of irregular light interference and avoid glare. However, if the curvature of the lens itself cannot be in the optical standard refractive state, the polarizing effect will be weakened, affecting the authenticity of the image, and it is poor durable.
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