Compact 3D Display Lighting via Spectral Filter Wheel
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Solution Overview
Problem
Current 3D image display technologies face challenges such as the need for expensive and fragile silver screens, head orientation requirements, high costs of shutter glasses, and color distortion in existing methods like Anaglyph, Linear Polarization, Circular Polarization, and Shutter Glasses, which limit their practicality and effectiveness for full-color images.
Innovation Solution
A compact lighting arrangement using spectral filters and low-power LEDs to create separate channels of light with distinct spectral properties, allowing for efficient backlighting and projection of 3D images by alternating the energization of LEDs to produce complementary spectra, which are then directed or reflected to illuminate specific regions of a modulating panel, such as an LCD display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spectral filters are used for left/right eye separation in 3D projection, then full color images can be displayed with good color accuracy, but the system requires complex filter switching mechanisms that increase device complexity
Solution Approach 1:
The patent employs periodic action by switching between different spectral filters at the frame rate frequency. The filter wheel rotates to present different filters (e.g., cyan for left eye, red for right eye) in alternating frames, enabling spectral separation for 3D display while maintaining full color capability through timed filter changes
Solution Approach 2:
The patent segments the spectral filtering function by using multiple discrete filters arranged on a rotating wheel rather than a single complex filter. Each filter handles a specific spectral band for a specific eye, dividing the overall filtering task into manageable segments that can be switched periodically
2Manufacturing precision
If a filter wheel is used to switch between left and right eye filters, then spectral separation for full color 3D is achieved, but the mechanical moving parts increase device complexity and reduce reliability
Solution Approach 1:
The filter wheel performs periodic rotation synchronized to the frame rate, presenting the appropriate filter for each eye during its designated frame. This periodic switching enables spectral separation while the mechanical complexity is confined to a single rotating assembly rather than multiple moving components
Solution Approach 2:
The rotating filter wheel serves multiple functions: it acts as both the switching mechanism for different spectral filters and the mounting structure for all filters. A single mechanical component (the wheel) performs the work of multiple individual filter holders, reducing overall mechanical complexity
3Manufacturing precision
If linear polarization is used for 3D separation, then full color images can be displayed, but the system requires expensive and fragile silver screens
Solution Approach 1:
The patent extracts the spectral separation function from the projection screen and places it in the projector itself via the filter wheel. By performing the filtering operation before light reaches the screen, the system eliminates the need for specialized silver screens, using standard projection screens instead
Solution Approach 2:
The spectral filters in the projector act as intermediaries that separate the left and right eye images by wavelength before projection. This intermediary filtering mechanism replaces the need for polarization-preserving silver screens, allowing use of conventional screens while maintaining 3D separation
4Reliability
If shutter glasses are used for temporal multiplexing, then active shuttering provides good 3D separation, but the glasses are expensive, require batteries, and are hard to clean
Solution Approach 1:
Instead of placing the active switching component in the glasses (as with shutter glasses), the patent inverts the approach by placing the passive spectral filters in the projector and using passive eyewear. The active temporal multiplexing is performed by the projector's filter wheel rather than the glasses, reversing where the active components are located
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 cost-effective and practical method for displaying full-color 3D images without the need for expensive silver screens or complex shutter glasses, minimizing crosstalk and maintaining color accuracy by using spectral separation techniques in a compact and efficient manner.
Implementation Method 1
Spectral Separation provides separation at the projector by filtering the left and right eye spectrally
Implementation Method 2
a second channel of light having second properties produced by reflecting light off the spectral filter
Data Source
AI summary
A compact arrangement of 3D filters is provided by a light source such as an LED and a spectral filter positioned to divide light from the light source into first and second lights having first and second spectral properties. A plurality of the compact sources may be arranged to illuminate (e.g., backlight) a modulator of a display (e.g., an LCD display). The modulator may be configured such that one region is illuminated by the first light and another region is illuminated by the second light (un modulated buffer between regions may be utilized to prevent crosstalk between the regions). The first and second lights are then modulated, for example, according to first and second channels of a 3D display.