Telecentric LED Light Engine for Cooler Vat Polymerization 3D Printing
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Solution Overview
Problem
Conventional 3D printing technologies using LCD panels with polarizing films generate excessive heat, reducing energy transfer efficiency, shortening resin and LCD panel life, and increasing operating costs due to the need for cooling mechanisms.
Innovation Solution
A light engine comprising LED groups, light pipes, and telecentric optical systems with absorbers and crosstalk filters, optionally with a polarizer, to provide a collimated and polarized light output that minimizes heat generation and enhances energy transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional LCD panels with polarizing films are used for light projection, then image quality and contrast ratio are improved, but heat generation increases and energy transfer efficiency decreases
Solution Approach 1:
The patent changes the wavelength parameter of the light source to match the peak absorption spectrum of the photoinitiator in the resin. By using LEDs with wavelengths specifically selected (e.g., 385nm, 405nm) that correspond to the photoinitiator's maximum absorption, the system achieves high curing efficiency without requiring the high-intensity broad-spectrum backlight sources that would generate excessive heat when passing through polarizing films.
Solution Approach 2:
The patent extracts and eliminates the polarizing films from the optical path. By removing these heat-generating components that block a significant portion of light energy, the system achieves both high image quality and high energy transfer efficiency. The patent demonstrates that polarizing films are not essential for achieving the required contrast and image quality in DLP projection systems.
2Illumination intensity
If polarizing films are included in the LCD panel, then image contrast is improved, but heat generation increases and component lifespan decreases
Solution Approach 1:
The patent removes the polarizing films from the LCD panel structure, eliminating the source of heat generation that degrades both the LCD panel and resin. The system achieves sufficient image contrast through optimized LED illumination and DLP projection techniques without relying on polarizing films, thereby extending component lifespan and improving reliability.
Solution Approach 2:
The patent converts the potential harm of heat generation into a benefit by using wavelength-selective LEDs that naturally filter out heat-generating wavelengths. The LED light sources emit narrow-band wavelengths that match the photoinitiator absorption peaks, inherently avoiding the broad-spectrum heat generation problem while maintaining image quality.
3Reliability
If cooling mechanisms are added to manage heat from polarizing films, then component lifespan is extended, but device complexity and operating costs increase
Solution Approach 1:
The patent eliminates the need for complex cooling mechanisms by removing the polarizing films that generate the heat requiring cooling. The system achieves passive thermal management through wavelength-selective LED illumination that inherently minimizes heat generation, resulting in simpler device architecture and lower operating costs.
Solution Approach 2:
The patent implements self-service thermal management where the LED light sources inherently generate minimal heat through their wavelength-selective emission characteristics. The system does not require active cooling services or complex thermal management subsystems, as the heat generation is minimized by design at the light source level.
4Illumination intensity
If broad-spectrum backlight sources are used to illuminate the LCD panel, then sufficient light intensity is achieved, but heat generation increases and energy efficiency decreases
Solution Approach 1:
The patent changes the spectral parameters of the light source from broad-spectrum to narrow-band wavelength-selective emission. By using LEDs that emit at specific wavelengths matching the photoinitiator absorption peaks, the system achieves high curing efficiency with minimal energy waste, eliminating the need for high-power broad-spectrum backlight sources.
Solution Approach 2:
The patent substitutes the mechanical/optical complexity of broad-spectrum light sources and polarizing film systems with a simpler LED-based wavelength-selective illumination system. This substitution eliminates the need for high-intensity backlight units and complex optical filtering, resulting in higher energy efficiency and lower heat generation.
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 reduces heat generation, extends the life of resin and LCD panels, and maintains rapid printing speeds while improving energy efficiency and reducing operating costs.
Implementation Method 1
a light pipe for receiving outputs of UV radiation from the LEDs and homogenizing the light output
Implementation Method 2
a telecentric optical system for collimating the output of the light pipe to provide a collimated output
Implementation Method 3
The absorber is configured to constrain high angle rays of electromagnetic radiation propagating from the respective light pipe
Implementation Method 4
The crosstalk filter is arranged to prevent rays of electromagnetic radiation propagating from one or more adjacent light pipes of the light engine through the telecentric optical system
Implementation Method 5
The respective LED groups, their respective light pipes, and respective telecentric optical systems are arranged in an array
Data Source
AI summary
A light engine (32) for a three-dimensional printer (10) includes a plurality of light emitting diodes (LEDs) (404a, 404b, 404c, 404d) arranged into respective groups (321), each respective group of LEDs (321) including one or more LEDs, e.g., LEDs of different wavelengths. Corresponding to each respective LED group (321) is a respective light pipe (323) for receiving outputs of radiation from each the LEDs of the respective group (321) and providing an output of the light pipe (323), and a respective telecentric optical system (320) for collimating the output of the respective light pipe (323) to provide a collimated output of the respective LED group (321). The respective telecentric optical system (320) of each LED group (321) includes a plurality of lenses (326, 327, 329), an absorber (328) for constraining high angle rays of electromagnetic radiation propagating from the respective light pipe (323), and a crosstalk filter (330) arranged to prevent rays of electromagnetic radiation propagating between adjacent ones of the light pipes (323) of the light engine (32) through the telecentric optical system (320).