I. development stage of Led diffusion plate:
 

1. Add particles with diffusion effect to improve the shading and cost-performance of light source;
 

2. Improved diffusion effect, improved appearance performance and improved light transmittance;
 

3. Optimize optical properties, improve UV resistance, impact resistance, light efficiency and light distribution requirements;
 

4. High temperature resistance and high light transmittance are required to improve the product fog value, which is suitable for use in close irradiation environment.

Ii. Optical characteristic values of Led diffusion plate:
 

Generally, the optical properties of transparent and translucent plastics, such as plate, chip, thin film and tube, have been controlled. The transmittance (transmittance) and haze have been evaluated through testing. China was proposed by the former ministry of chemical industry of the People's Republic of China, drafted by chenguang chemical research institute of the former ministry of chemical industry, and promulgated by the state administration of standards.

It is defined as follows:
 

1. Luminous Flux -- the ratio of the Luminous Flux flowing through a sample to the Luminous Flux that can be Luminous onto the sample, expressed as a percentage.
 

2. Haze -- the ratio of the scattered light flux deviating from the incident light direction through the sample to the transmitted light flux, expressed as a percentage (for this method, only the scattered light flux deviating from the incident light direction more than 2.5 degrees is used to calculate the haze). A cloudy or cloudy appearance of the interior or surface of a transparent or translucent material caused by light scattering. Expressed as a percentage of the scattered flux to the flux through the material. It is an important parameter of optical transparency of transparent or translucent materials.
 

3. The refractive index -- -- -- -- -- no matter how to change your light transmittance or fog degree, it had already decided in quality (density) of its optics, the greater the refractive index is, the less the transmittance, nothing to do with thickness, transmittance and haze is a measure of material transparency does not necessarily apply for diffuser, in general, light transmittance and fog degrees, inversely proportional relationship between vice versa it is.
 

More than just definition of transparent material, it is in the 80 s domestic transparent sheet to opaque, cited foreign specifications, after all, in 1981, no country or region, to make clear the definition of a diffuser specification, even if not in 2014 to a formal specification, this noun it straight from the earliest type of backlight modules, so the reference is not completely transparent diffuser plate specification to show, that is not defined standards in our country, therefore not suitable for solid state lighting, with the development of LED light source and LED lighting, its application to present technical bottleneck. Because the domestic manufacturers do not have an optical engineering experts, are still in the processing stage.