LED Optical Engine for DLP Projectors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional DMD projector systems using short arc discharge lamps face limitations in color gamut, efficiency, and complexity due to the use of color wheels and light integrators, while LED-based systems struggle with optical loss and inefficiency in coupling light to fiber bundles and fly-eye lenses.
Innovation Solution
An LED optical engine system that eliminates traditional homogenizers like fly-eye lens arrays and integrator waveguides, using collimation lenses, a cross-dichroic combiner, and optical waveguides to directly image uniform LED panels onto a DMD panel, with aberration and defocusing techniques to achieve efficient light distribution and minimize gaps between sub-light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If short arc discharge lamps are used as light source, then high brightness is achieved, but UV and IR light cause reduced component lifetime and require additional cooling
Solution Approach 1:
The patent extracts and removes the harmful UV and IR wavelength components from the light source spectrum while retaining the useful visible light. This is achieved by selecting LED light sources that inherently emit primarily in the visible range, thereby eliminating the harmful effects of UV and IR radiation on optical components and display panels while maintaining high brightness.
Solution Approach 2:
The patent changes the spectral parameters of the light source by transitioning from broad-spectrum discharge lamps to narrow-spectrum LEDs with specific wavelength emissions. This parameter change allows precise control over the emitted spectrum, maintaining high visible light output while eliminating harmful UV and IR components, thus improving component lifetime without sacrificing brightness.
2Ease of operation
If color wheel is used to filter white light, then sequential color light is provided, but color gamut is limited and ambient noise is generated
Solution Approach 1:
The patent replaces the mechanical color wheel system with a static optical arrangement using dichroic mirrors and beam splitters. Instead of mechanically rotating a color wheel to separate wavelengths, the system uses fixed optical elements to spatially separate and combine light paths for different colors, thereby eliminating moving parts, ambient noise, and the limitations of sequential color filtering while achieving full-color output simultaneously.
3Illumination intensity
If fly-eye lens array or light pipe integrator is used, then light is collected and homogenized, but system becomes bulky and complex
Solution Approach 1:
The patent extracts and eliminates the bulky fly-eye lens array and light pipe integrator components from the optical system. Instead of using these complex homogenizing devices, the invention employs direct imaging optics and carefully designed LED arrays with integrated diffusers that achieve uniform light distribution across the display panel without requiring large, complex intermediate optical elements.
Solution Approach 2:
The patent uses thin film diffusers integrated directly with the LED structure to achieve light homogenization. These thin film elements provide the necessary light scattering and uniformity functions that traditionally required bulky fly-eye lenses or long light pipes, thereby maintaining compact system size while achieving the desired light distribution uniformity.
4Use of energy by moving object
If LEDs are coupled to fiber bundles, then light transmission is achieved, but coupling and transmitting losses reduce efficiency
Solution Approach 1:
The patent extracts and eliminates the fiber bundle coupling stage from the optical path. Instead of coupling LED light into fiber bundles and transmitting through them, the system uses direct free-space optical coupling from LED arrays through simple lenses and mirrors to the display panel. This eliminates the coupling losses and transmitting losses inherent in fiber bundle interfaces while maintaining efficient light transmission.
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 system achieves high light efficiency, improved color gamut, reduced complexity, and longer component life by eliminating UV and IR issues, resulting in a compact, cost-effective, and efficient LED-based optical engine for DMD projectors.
Implementation Method 1
a first collimation lens (104), a second collimation lens (105), and a third collimation lens (106) that collimate light from the red, green and blue LEDs, respectively
Implementation Method 2
a cross-dichroic combiner (107) that combines the collimated light
Implementation Method 3
a condenser lens (108) that focuses the combined light onto a digital micro-mirror device (DMD) panel (109)
Implementation Method 4
with aberration and defocusing techniques to achieve efficient light distribution
Data Source
AI summary
An optical light engine (100) includes one or more light-emitting diode (LED) panels (101, 102, 103) that are combined into a common path and directly imaged onto panel device to provide a source of light to a microdisplay panel (109). Preferably, the LED panel (101, 102, 103) is shaped such that the aspect ratio of light propagating the LED panel is substantially equal to the light received at the microdisplay panel (109). An aspect ratio of 4:3 or 16:9 is typically selected in view of the sizes of the LED panels used in the light engine.