Resin lenses are increasingly favored by people. Because of their high impact resistance and non-breaking, the lenses can be made thinner and have no problem with frameless and half-frame frames. From another point of view, its advantages are also weaknesses. It is not easy to break because of its low hardness, so the wear resistance of the lens surface is not good enough and it is easy to be scratched. Although it can be hardened and filmed, it needs to be carefully protected to maintain its longevity.
Firstly, the resin lens is an organic material, and the inside is a polymer chain structure, which is connected to form a three-dimensional network structure, the intermolecular structure is relatively relaxed, and there is a space between the molecular chains which can generate relative displacement. The light transmittance is 84%-90%, good light transmission, and the optical resin lens has strong impact resistance.
Let's talk about the advantages of resin lenses.
First of all, it is light. The general resin lens is 0.83-1.5, and the optical glass is 2.27~5.95.
Second - Strong impact resistance. The impact resistance of the resin lens is generally 8 to 10 kg/cm2, which is several times that of the glass, so it is not easily broken, and is safe and durable.
Third - Good light transmission. In the visible light region, the transmittance of the resin lens is similar to that of the glass; the infrared light region is slightly higher than the glass; the ultraviolet region starts with 0.4 um, and the light transmittance decreases with the decrease of the wavelength, and the light with a wavelength of less than 0.3 um is almost all. absorb.
Fourth - Low cost. Injection molded lenses can be mass-produced by manufacturing a precision mold, saving processing costs and time.
Fifth – It can meet special needs. For example, the production of aspherical lenses is not difficult, and glass lenses are difficult to handle.
Disadvantages are: surface wear resistance, chemical resistance is worse than glass, surface is easy to scratch, water absorption is larger than glass, these shortcomings can be improved by coating method. The fatal disadvantage is that the coefficient of thermal expansion is high, the thermal conductivity is poor, the softening temperature is low, and it is easily deformed to affect the optical properties.