Filter-Free Projector Using RGB LEDs and DMD
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Solution Overview
Problem
Conventional projectors for portable devices are hindered by the complexity and size of their optical systems, which include multiple lenses and a color filter wheel, leading to high temperatures, large size, and low-frequency flashing effects, making them unsuitable for slim, portable designs.
Innovation Solution
A filter-free projector using a color light source unit with a digital mirror device panel and a projection lens, where the light source includes organic electroluminescence, LED, or field-emitting elements to emit red, green, and blue colors, controlled by a color control module to switch colors rapidly, eliminating the need for a color filter wheel and multiple lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional projector uses a white light lamp and multiple reflector lenses and light-split lenses to split white light into three colors, then the projector can achieve color projection, but the optical lens set becomes expensive and the mechanism becomes complicated and the size becomes difficult to reduce
Solution Approach 1:
The patent extracts and removes the color filter wheel and multiple lenses from the optical system. Instead of using a white light source with filters to create colors, the invention uses separate red, green, and blue light sources that directly emit their respective colors without needing filters or splitting mechanisms. This extraction of the filtering mechanism eliminates the need for expensive and complex optical lens sets.
Solution Approach 2:
The patent segments the white light source approach into three separate monochromatic light sources (red LED, green LED, blue LED). Each light source independently provides one primary color, eliminating the need for optical components that would otherwise be required to split and filter white light into its spectral components. This segmentation simplifies the optical system while maintaining color projection capability.
2Adaptability or versatility
If a conventional projector uses a color filter wheel driven by a motor to achieve color projection, then the projector can display colors, but the size of the device increases and it becomes difficult to embed into portable devices
Solution Approach 1:
The patent replaces the mechanical color filter wheel system with an electronic control system. Instead of physically rotating filters using a motor, the invention uses three independent LED light sources that can be electronically controlled to emit red, green, and blue light. This substitution eliminates the mechanical moving parts, motor, and large-sized filter wheel, dramatically reducing the device volume while maintaining full color projection capability.
Solution Approach 2:
The patent implements dynamic control of the three LED light sources to create color projection. By dynamically switching between and combining the red, green, and blue LEDs in different patterns and intensities, the system achieves full-color projection without any mechanical moving parts. This dynamic electronic control replaces the static mechanical filter wheel approach.
3Use of energy by moving object
If a conventional projector uses a white light lamp as light source, then the projector can provide illumination for projection, but the lamp source generates heat at high temperature and requires multiple lenses to cooperate
Solution Approach 1:
The patent changes the fundamental parameters of the light source by replacing the broad-spectrum white light lamp with three narrow-band monochromatic LED light sources. Each LED emits light at a specific wavelength range (red, green, or blue) with high luminous efficiency and low heat generation. This parameter change from broad-spectrum to narrow-band light sources eliminates the need for heat management and reduces the number of optical components required.
Solution Approach 2:
The patent extracts and removes the heat-generating white light lamp from the system. By using LEDs that are inherently more energy-efficient and produce significantly less heat, the invention eliminates the thermal management requirements and the complex lens systems needed to handle the broad spectrum of white light. This extraction of the problematic light source component resolves both the heat and lens complexity issues.
4Adaptability or versatility
If a conventional projector uses a high speed revolution color wheel to achieve color projection, then the projector can display colors, but a low-frequency flashing effect occurs
Solution Approach 1:
The patent replaces the mechanical rotating color wheel with an electronic control system that independently manages three LED light sources. By electronically switching between and combining the red, green, and blue LEDs at controlled rates, the system achieves color projection without the mechanical rotation that causes flashing effects. This electronic substitution eliminates the synchronization issues and visual artifacts associated with mechanical color wheels.
Solution Approach 2:
The patent maintains continuous color projection by dynamically controlling the three LED light sources without interruption. Unlike a rotating color wheel that must physically move between positions, the electronic control system can instantly switch between and combine the LED outputs, providing continuous color projection without the gaps or flashing that occur during mechanical rotation. This continuity eliminates the low-frequency flashing effect.
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
This solution enables a compact, low-power projector that can be integrated into portable devices, reducing size, heat, and power consumption while maintaining high image quality and brightness, with faster color switching that minimizes afterimage persistence.
Implementation Method 1
The light source unit includes an organic electroluminescence element, an LED element, a field-emitting element laser diode, or an electroluminescence element to emit illumination of red, green, or blue
Implementation Method 2
a digital mirror device panel having a plurality of mirror elements each being controlled so as to reflect light fed from the light source unit
Data Source
AI summary
A filter-free projector includes a light source unit to generate light beams with different colors and a color control module coupled to the light source unit for switching the light source unit to emit one color light at a time. A digital mirror device panel having a plurality of mirror elements is provided so as to reflect light fed from the light source unit. A projection lens is positioned in the reflected light path from the digital mirror device panel to project the image.