Light Emitting Device with Density-Matched Diffusion Film
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Solution Overview
Problem
Conventional light emitting devices face issues with visually apparent graininess near the light entry side and decreased luminance far from the light entry side due to the limitations of diffusion films, which cannot adjust haze levels effectively based on distance from the light source, leading to defects in uniformity and luminance.
Innovation Solution
A light emitting device design that includes a light guiding plate with varying densities of luminous dots and a diffusion film with corresponding densities of diffusion dots, where the sum of densities in each area approximates a predetermined value, ensuring uniform illumination and maintained luminance by matching the density distribution of luminous and diffusion dots to the distance from the light source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a diffusion film with high haze is used to reduce graininess near the light entry side, then the graininess problem is solved, but the luminance far from the light entry side decreases significantly
Solution Approach 1:
The diffusion film is divided into multiple regions along the optical path, with each region having a different haze value. Regions closer to the light entry side have higher haze to mask graininess, while regions farther away have lower haze to maintain luminance. This spatial variation in haze properties resolves the contradiction between reducing graininess and maintaining luminance.
Solution Approach 2:
The haze parameter of the diffusion film is changed continuously or in steps along the optical path. By adjusting the haze value according to the position, the film adapts to the varying light intensity distribution, ensuring optimal performance at different locations without sacrificing overall luminance.
2Illumination intensity
If a diffusion film with low haze is used to maintain luminance far from the light entry side, then luminance is preserved, but visually apparent graininess appears near the light entry side
Solution Approach 1:
Different regions of the diffusion film are assigned different haze values based on their position relative to the light entry side. This local differentiation allows the film to address graininess where it occurs while preserving luminance in regions where light intensity is lower.
Solution Approach 2:
The haze parameter varies spatially across the diffusion film, creating a gradient or stepped distribution that matches the light intensity profile. This parameter variation enables the film to maintain high luminance overall while providing localized haze control to eliminate graininess.
3Object-affected harmful factors
If diffusion films are placed only on specific areas to solve grainy-light-spot problems, then graininess is reduced in those areas, but visually noticeable differences appear at the borders
Solution Approach 1:
The diffusion film implements a continuous spatial variation in haze properties across its entire surface, rather than applying uniform haze only in specific areas. This gradual transition ensures that no sharp borders exist between regions of different haze levels, eliminating visual discontinuities while maintaining graininess control where needed.
Solution Approach 2:
The haze distribution in the diffusion film is designed to transition smoothly across different regions, creating a dynamic gradient rather than static, abrupt changes. This dynamic variation in optical properties ensures visual uniformity while addressing local graininess issues.
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 addresses the graininess and luminance issues by providing uniform illumination and maintaining high luminance without visually noticeable differences, overcoming the limitations of conventional diffusion films.
Implementation Method 1
one of the surfaces of the light guiding plate usually has a plurality of microstructures or dots for canceling the total internal reflection of light
Implementation Method 2
the light guiding plate receives the light emitted from the light source module and produces a uniform surface source of light
Implementation Method 3
a conventional diffusion film is only capable of uniform haze... the higher haze, the better hazing (or concealing) capability
Data Source
AI summary
The present disclosure discloses a light emitting device. A plurality of luminous dots disposed on a light guiding plate is distributed on a first area and a second area of the light guiding plate by a first density and a second density, respectively. A plurality of diffusion dots disposed on a diffusion film is distributed on a third area and a fourth area of the diffusion film by a third density and a fourth density, respectively. The first area of the light guiding plate is projected to the third area of the diffusion film, and the second area of the light guiding plate is projected to the fourth area of the diffusion film. A sum of the first density and the third density after an approximation and a sum of the second density and the fourth density after the approximation are both equal to a predetermined value.