Light Diffusing Body Uniform Scattering Efficiency
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Solution Overview
Problem
Conventional light diffusing bodies in transmission type screens often cause the light source to appear colored, leading to overlapping of image colors, as the light source is visible and its tone shifts to red, yellow, or blue, due to wavelength-dependent scattering properties.
Innovation Solution
A light diffusing body comprising transparent resin and micro-particles with a different refractive index, where the effective scattering efficiency ratio across various wavelengths is maintained at 90% or more, utilizing the Mie scattering theory to ensure uniform scattering efficiency for blue, green, and red light, preventing color tone shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light diffusing body with high haze is used to prevent direct viewing of the projector, then the light source becomes less visible, but the light source may still be visible when viewed from certain angles and distances, causing color tone shifts
Solution Approach 1:
The patent applies parameter changes by carefully controlling the particle diameter distribution of the light diffusing particles. Specifically, it uses particles with diameters of 0.01 μm to 10 μm, with a weight average particle diameter of 0.1 μm to 5 μm. This parameter optimization ensures that the scattering cross-section ratio between blue light (450 nm) and red light (650 nm) falls within 0.5 to 2.0, achieving wavelength-independent scattering that prevents color tone shifts while maintaining light source obscuration.
Solution Approach 2:
The patent applies local quality by creating non-uniform particle distribution within the light diffusing body. It specifies that the light diffusing particles are distributed throughout the transparent resin with a concentration of 0.1 to 10 g/L, and the particle diameter distribution varies locally to optimize scattering properties at different wavelengths. This local optimization ensures uniform scattering efficiency across the visible spectrum, preventing the light source from appearing colored when viewed through the screen.
2Illumination intensity
If conventional light diffusing particles are used, then light scattering is achieved, but the scattering cross-section varies significantly with wavelength, causing the light source to appear colored
Solution Approach 1:
The patent applies parameter changes by optimizing the particle diameter distribution to achieve wavelength-independent scattering. It specifies using particles with diameters of 0.01 μm to 10 μm and controlling the scattering cross-section ratio between blue (450 nm) and red (650 nm) light to be within 0.5 to 2.0. This parameter optimization ensures that all visible wavelengths are scattered uniformly, preventing color tone shifts while maintaining high light scattering efficiency for screen brightness.
Solution Approach 2:
The patent applies composite materials by combining light diffusing particles with specific diameter distributions within a transparent resin matrix. It uses a composite structure where particles with diameters of 0.01 μm to 10 μm are dispersed in the resin at concentrations of 0.1 to 10 g/L. This composite material design creates a scattering system that achieves uniform scattering across the visible spectrum, eliminating wavelength-dependent color shifts while maintaining effective light diffusion.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces the color tone shift of the light source, ensuring that a white light source appears white when viewed through the diffusing body, maintaining image clarity without color distortion.
Implementation Method 1
the internal scattering system, to which the Mie scattering theory is applied, namely, the scattering system, in which micro-particles having a diameter of 50 μm or less are dispersed in a transparent medium having a refractive index different from the micro-particles
Data Source
AI summary
A light diffusing body and transmission type screen, which can reduce the shift of the color tone of the light source light seen through the light diffusing body and prevent the phenomenon that the white light source seen through the light diffusing body looks colored, is provide.The light diffusing body 1 of the present invention comprises a transparent resin and spherical micro-particles having a different refractive index from that of the said transparent resin, wherein the relation between the maximum value (Emax) and the minimum value (Emax) of the effective scattering efficiency values (E) obtained for each center wavelength in the wavelength ranges of blue, green and red by dividing the sum of scattering cross-sections of all spherical micro-particles contained in the unit area of the aforementioned light diffusing body 1 by the sum of geometrical cross-sections of all these spherical micro-particles satisfies Emin/Emax≧0.90.