Why do We Develop Linshang Spectrum Transmission Meter?
LS108 spectrum transmission meter is a professional equipment for testing the transmittance of spectacle lenses. The instrument mainly tests the transmittance of three bands. It is designed based on the parameters that are currently valued by the spectacle lens industry.
1. Why test the visible light transmittance at 550nm?
The most basic function of ophthalmic lenses should be light transmission. If the light transmittance of the lens is not good, it will directly affect the user's visual experience, so it is necessary to detect the light transmittance of the spectacle lens. The visible light range is 380-760nm, of which 550nm is the most sensitive wavelength for the human eye. The LS108 spectrum transmission meter has a built-in 550nm visible light source that is most sensitive to the human eye. It is used to test the visible light transmittance (light transmittance) of the lens.
2. Why test the 395nm ultraviolet transmittance?
The wavelength of ultraviolet rays in sunlight is mainly 200-380nm. The damage of ultraviolet rays to the human eye can not be ignored. The crystals in the eyeballs will harden due to excessive ultraviolet rays. The eyes cause obvious damage, which can only cause itchy eyes, tears, photophobia, redness and swelling. However, the damage of ultraviolet rays can slowly accumulate. Accumulation to a certain extent will cause cataracts, glaucoma and other acting skills.
At present, most lenses have achieved a good UV blocking effect, but glasses still need to achieve a high visible light transmittance. The visible light range is 380-760nm (some standards are divided into 400-760nm), so the UV of the lens transmission will increase with increasing wavelength. The built-in 395nm light source of the LS108 spectrum transmission metercan be divided into purple light or UVV ultraviolet light. If the lens has a low transmittance (that is, high blocking rate) to 395nm purple light, then the ultraviolet light blocking performance of other shorter wavelengths would be better.
3. Why test the 430nm blue light transmittance?
The damage of blue light to the human eye is mainly manifested in the eye pathological hazards and human rhythm hazards that cause myopia, cataracts and macular degeneration. Moreover, if the human eye is exposed to blue light for a long time, it is prone to visual fatigue. There is a large amount of blue light in our work and life. Computer screens, mobile phone screens and fluorescent lights emit blue light. Therefore, many eyeglass lens manufacturers have also launched anti-blue light lenses. The blue light harmful to the human eye is mainly short-wave blue light with a wavelength range of about 400-450nm. Therefore, the LS108 spectrum transmission meter chose a 430nm light source to detect the blue light transmittance.
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