Random Recess-Protrusion Diffuser for Uniform Radiant Intensity
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Solution Overview
Problem
Current diffusers face challenges in achieving smooth radiant intensity distribution without generating unevenness and are costly to manufacture, especially when using microlens arrays, which require complex machining and are difficult to produce in large areas.
Innovation Solution
A diffuser with a recess-protrusion structure on a plane, where the x-axis is divided into intervals with varying lengths between Sx-min and Sx-max, and z-coordinates with a ratio Anx-max/Ax-min < 1.3, allowing for easy control of radiant intensity and reduced unevenness, manufactured using a method that includes etching and synthetic resin coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a microlens array is used to control radiant intensity distribution, then radiant intensity control is improved, but manufacturing cost and complexity increase due to required machining or laser processing
Solution Approach 1:
The patent uses a master mold with a random recess-protrusion structure that is copied onto multiple diffuser substrates through injection molding. This copying approach eliminates the need for complex machining or laser processing of each individual diffuser, while maintaining the radiant intensity control functionality. The master mold is created once and then used to mass-produce diffusers with consistent optical properties.
Solution Approach 2:
The patent changes the manufacturing approach from precision machining of microlenses to injection molding of recess-protrusion structures. By altering the manufacturing parameters and process method, the patent achieves similar optical functionality with significantly reduced complexity and cost.
2Illumination intensity
If a microlens array is used to achieve smooth radiant intensity distribution, then transmittance is improved, but unevenness in radiant intensity distribution occurs due to diffraction from periodic structure
Solution Approach 1:
The patent employs an asymmetric, random recess-protrusion structure instead of a periodic microlens array. This random arrangement eliminates the diffraction effects caused by periodicity while maintaining effective light diffusion and transmittance properties.
Solution Approach 2:
The patent creates local variations in the surface structure with recesses and protrusions that have specific depth and width characteristics. These local structural variations are designed to control light scattering at the micro-scale while the overall random distribution ensures uniform macro-scale radiant intensity.
3Stability of the object's composition
If a random recess-protrusion structure is used to reduce diffraction unevenness, then uniformity of radiant intensity is improved, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent pre-defines the random recess-protrusion structure in a master mold before mass production. By establishing the random structure in advance during mold fabrication, the subsequent injection molding process can reproduce it with high consistency, making manufacturing precision easier to control.
Solution Approach 2:
The patent specifies particular parameter ranges for the recess-protrusion structure (depth, width, spacing) that balance the need for randomness with manufacturability. By constraining parameters within specific ranges, the patent achieves both uniform radiant intensity distribution and practical manufacturing control.
4Stability of the object's composition
If Gaussian diffuser with continuous rough surface is used to achieve smooth radiant intensity distribution, then uniformity is improved, but degree of freedom of design is reduced and transmittance deteriorates when divergence angle is enlarged
Solution Approach 1:
The patent segments the continuous rough surface into discrete recess and protrusion elements. This segmentation allows for greater design flexibility in controlling light scattering while maintaining smooth radiant intensity distribution. The discrete elements can be independently optimized for different divergence angles and optical requirements.
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 diffuser achieves even radiant intensity distribution with reduced unevenness and is easier to manufacture, overcoming the limitations of existing technologies by controlling the divergence angle and using a simpler manufacturing process.
Implementation Method 1
a Gaussian diffuser that refracts rays of light having entered the diffuser to achieve a Gaussian distribution of radiant intensity
Implementation Method 2
diffusers for achieving a smooth distribution of radiant intensity or of irradiance
Data Source
AI summary
A diffuser is provided with a recess-protrusion structure formed on a plane. When a z-axis is defined as a normal to the plane, an x-axis is defined on the plane, the x-axis is divided into plural intervals, Snx represents length of an interval nx, Sx-max and Sx-min represent the maximum and the minimum of Snx, respectively, the relationship2<Sx-max/Sx-minholds, Snx varies on a random basis between Sx-min and Sx-max, in an xz cross section, a recess portion and a protrusion portion are formed on each of adjacent intervals along the x-axis, respectively, and when dznx represents a difference between the maximum and the minimum of z coordinate of the recess-protrusion structure in the interval nx in the xz cross section, Anx represents a ratio between dznx and Snx, Anx-max and Anx-min represent the maximum and the minimum of Anx, the relationshipAx-max/Ax-min<1.3holds.