Sunglasses belongs to the category of individual eye facial protection articles, to measure the quality of technical indicators mainly embodied in the top of coke, uv protection, mechanical impact, from several aspects such as being able to stop the dazzling glare.
A, lens uv transmission ratio detection principle to transmittance measurement of lenses, cannot handle for spectral transmittance of various wavelengths in the simple average, and should be in accordance with the different wavelength is different, the weight of is obtained by weighted integral of spectral transmittance.
Person's eye is a simple optical system, product quality inspection glasses must first take into account the human eye to different wavelengths of sensitivity of optical radiation.
To sum up, the human eye is sensitive to green light, so the green wavelengths of light transmittance and had a great influence on the lens light transmittance, namely, the weighting of green light wave band;
On the other hand, due to the human eye is not sensitive to the purple and red, purple and red light transmittance of high and low for the lens light transmittance is small, the influence of the purple and red light band there is less weight.
The lens of the effective methods of uv protection is part of UVA and UVB transmittance spectrum quantitative measurement and analysis.
2, lens uv transmittance testing instrument and the method can use spectral transmittance test instrument for the determination of spectral transmittance of ultraviolet area, in order to determine the ultraviolet transmission performance quality of the sample.
The spectral transmission device into the computer serial port, to start operating procedures, in 23 ℃ + 5 ℃ environment correction (
Part must be confirmed before calibration measurement without the lenses or filter)
, set test wavelength range is 280 ~ 480 nm, observed under the condition of the transmittance curve zoom lens of ultraviolet (uv) light.
Later, will be the test lenses were placed in the test of rubber plug light transmittance test (
Note: test before the lens and testing the rubber plug is wiped clean)
3, ultraviolet transmission ratio measurement, the problems existing in the sunglasses of ultraviolet transmittance calculated taken to simple average method of spectral transmittance, and defined as the average transmittance.
In addition, QB2457 -
The medium wave ultraviolet (stipulated in the 99
Wavelength range is 290 NMT 315 nm.
For the same sample to be tested, if the QB2457 and IS08980 -
Measure 3 two definitions, the ultraviolet transmission ratio results are completely different.
According to the IS08980 -
3 the definition of the measurement, the UV -
B band transmittance calculated results is 60.
And if, in accordance with the QB2457 measurement, the definition of the UV -
B band transmission than the calculation results of 47.
The difference between two results 13.
Thus, reference to the standard difference will directly lead to technology, strives for the difference, will affect the measurement result accuracy and objectivity.
Measure the transmittance of glasses products, this problem can't be ignored.
The transmittance of sunglasses products and lens material test analysis, based on the spectral transmittance weighted integral value, exact results on sunglasses products quality, first to see if the material of the lens can block UVA and UVB rays, and can let visible light through more, to prevent dazzle function.
Through the above experiments show that the resin lenses of transmission performance is good, glass lenses, crystalline lens, CR - resin lenses
39 transmission performance is much better than the PMMA lens.