Two-Piece LCD Projector Semi-Field Sequence Display
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Solution Overview
Problem
Single LCD projectors have low energy conversion efficiency due to inefficient light valve modules, particularly the color filter (CF) device, leading to high manufacturing costs and user viewing fatigue from image flicker, while alternatives like 3LCD projectors are costly and complex to produce.
Innovation Solution
A two-piece LCD projector employing a semi-field sequence display method with red and blue LED light sources alternating synchronously and a constant green light source, eliminating the need for CF devices and utilizing dichroic glass for light convergence, resulting in high energy conversion efficiency and reduced viewing fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a single LCD projector uses a full-color LCD light valve with CF device, then color images can be displayed, but energy conversion efficiency is too low (only 2%-3.5%)
Solution Approach 1:
The patent removes the color filter (CF) device from the LCD light valve structure. By extracting this component that causes significant light loss (reducing efficiency from theoretical 33.3% to actual 2%-3.5%), the system achieves much higher energy conversion efficiency (over 25%) while maintaining color display capabilities through alternative means (dichroic mirrors for light separation and recombination)
Solution Approach 2:
The patent replaces the traditional CF-based color separation mechanism with a dichroic mirror-based optical system. Instead of using absorbing color filters that waste light energy, the system uses dichroic mirrors to reflect and redirect specific wavelength ranges, achieving color separation and recombination with minimal energy loss
2Ease of manufacture
If a DLP projector displays R, G and B field images in pure field sequence, then cost is reduced and production is simplified, but viewing fatigue caused by image flicker increases
Solution Approach 1:
The patent employs field sequence display with periodic switching of red and blue light sources synchronized with the LCD light valve refresh rate. This periodic action maintains production simplicity while reducing flicker perception by coordinating light source activation with the display refresh cycle, thereby reducing viewing fatigue
Solution Approach 2:
The patent uses a constant green light source that operates continuously without interruption, while red and blue sources alternate in synchronization with the display refresh. This continuity approach ensures stable green channel output and reduces overall flicker perception compared to complete field sequence switching of all colors
3Illumination intensity
If a 3LCD projector uses three single-color LCD light valves without CF device, then color richness and picture quality are improved, but manufacturing becomes cumbersome and cost increases
Solution Approach 1:
The patent merges the functions of three separate single-color LCD light valves into a single full-resolution LCD light valve. By combining the color separation function (achieved through dichroic mirrors) with a single display panel, the system maintains the color richness of 3LCD technology while dramatically simplifying manufacturing and reducing device complexity
4Use of energy by moving object
If the CF device is removed to improve energy efficiency, then light transmission efficiency increases, but the ability to display pure primary colors may be affected
Solution Approach 1:
The patent introduces dichroic mirrors as intermediary optical elements to perform color separation and recombination functions previously handled by CF devices. These mirrors act as mediators that reflect specific wavelength ranges while transmitting others, enabling pure primary color display without the light-absorbing CF layer and thereby maintaining high transmission efficiency
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 achieves high brightness output with low manufacturing thresholds and cost, improved energy efficiency, and reduced user fatigue compared to traditional projectors, maintaining simplicity and cost-effectiveness while surpassing the energy efficiency of 3LCD projectors.
Implementation Method 1
utilizing dichroic glass for light convergence
Implementation Method 2
red and blue LED light sources alternating synchronously
Implementation Method 3
a constant green light source
Data Source
AI summary
The disclosure provides a two-piece LCD (liquid crystal display) projector based on a semi-field sequence display manner, including first and second black and white transmission type LCD light valve modules, wherein the first LCD light valve module alternatively displays red and blue field images, which are alternatively illuminated by a red light source and a blue right source, of input video signals; the alternative lightening and extinguishing period of the red light source and the blue right source is synchronous with the alternative field of the red and blue field of this LCD light valve; the second LCD light valve module is used to display the green field image, which is constantly illuminated by the green light source, of the input video signal; the light passing through the first and second LCD light valve modules are converged by a light converging device.