Diffractive Optical Element for LED Irradiance Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
UV curing applications face challenges in achieving high enough irradiance within the limited time required for polymerization, as LED UV lamps emit light at various angles, leading to reduced light availability at the target surface.
Innovation Solution
Incorporating a diffractive optical element, such as a hologram, into the lighting module to partially collimate the divergent light from LEDs, increasing irradiance at the target surface while maintaining a uniform light distribution to prevent hot spots and uneven curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If LED arrays are used to provide UV light for curing, then power consumption and operating temperature are reduced, but the light divergence increases causing reduced irradiance at the target surface
Solution Approach 1:
A diffractive optical element is introduced as an intermediary component between the LED array and the target surface. This element mediates the light propagation by diffracting the divergent LED light into a more collimated beam, thereby increasing irradiance at the target without requiring additional power beyond what the LEDs already consume
Solution Approach 2:
The patent changes the optical parameters of the light propagation by using a diffractive optical element that modifies the divergence angle and spatial distribution of the LED light. This parameter change transforms the inherently divergent LED emission into a more directed beam with higher irradiance at the curing surface
2Illumination intensity
If the divergence of LED light is reduced to increase irradiance, then light availability at the target surface increases, but the complexity of the optical system increases
Solution Approach 1:
The diffractive optical element serves as a compact intermediary that achieves beam collimation without requiring complex optical assemblies. By using diffraction-based light manipulation rather than traditional lens or mirror systems, the patent reduces optical system complexity while maintaining high irradiance
Solution Approach 2:
The patent replaces potential mechanical optical adjustment systems with a static diffractive optical element that inherently controls light direction through its diffraction pattern. This substitution eliminates the need for complex mechanical positioning or adjustment mechanisms
3Productivity
If light is concentrated to increase irradiance, then curing effectiveness improves, but hot spots and uneven curing may occur
Solution Approach 1:
The diffractive optical element creates a controlled spatial distribution of light intensity across the target surface. By designing the diffraction pattern to specific local regions, the patent ensures that high irradiance is delivered uniformly across the curing area rather than concentrating it in a single point, preventing hot spots while maintaining curing effectiveness
Solution Approach 2:
The patent uses partial collimation of the LED light rather than complete concentration. The diffractive optical element provides just enough directional control to increase irradiance to effective levels while deliberately avoiding excessive concentration that would create hot spots and uneven curing
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 use of a diffractive optical element doubles the irradiance at a given distance and provides a more uniform light distribution, enhancing the curing process by acting like a point source and scattering light to prevent cracking or failures in the coating.
Implementation Method 1
Incorporating a diffractive optical element, such as a hologram, into the lighting module to partially collimate the divergent light from LEDs
Data Source
AI summary
A lighting module having an array of light-emitting elements on a substrate, at least one diffractive optical element arranged to receive light from the light-emitting elements and partially collimate the light. A method of packaging a lighting module including mounting at least one array of light-emitting elements on a substrate in a package, and enclosing the package with a window, the window has a diffractive optical element on a surface of the window closest to the array, the diffractive optical element arranged to partially collimate the light. A lighting module having an array of light-emitting elements on a substrate, at least one diffractive optical element arranged to receive light from the light-emitting elements and scatter the light into a random emission pattern to produce a uniform irradiance at a target surface.