Point light source refers to a light source that emits uniformly from a point to the surrounding space, while parallel light source refers to a set of parallel optical fibers without attenuation, similar to the effect of the sun's rays
In many light transmittance meters, these two light sources, light sources or parallel light sources are used. When the light transmittance testers of these two different light sources test ordinary glass with large thickness, the test data will also have deviations. Why the reason?
Because the light emitted by the parallel light source passes through the measured material in parallel, the direction of the light will not change, and there is almost no attenuation.
point light source is different. The light emitted by it is relatively scattered, so when the light from the point light source enters the glass, it will be refracted. The direction of refraction causes the light to converge toward the center, and the light received by the luminometer will increase. When the glass through which a point light source passes through is thicker, its light-gathering property is more obvious. Therefore, when using a light transmittance meter, it is best to choose a light transmittance meter with a parallel light path to measure glass. Linshang's LS116 light transmittance meter uses a parallel light source light path design, so it can measure large thickness materials, and the value will be More accurate.