PLM Zero-Order Light Routing for Uniform SLM Illumination
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Solution Overview
Problem
Projection-based displays face issues with nonuniform illumination due to zero-order light, which can cause variations in brightness across the projected image, reducing overall illumination and efficiency.
Innovation Solution
A method and device configuration that projects zero-order light through an optical tunnel and focusing optics onto a spatial light modulator (SLM) to provide uniform illumination by combining it with background image light, using a phase light modulator (PLM) to adjust micromirror heights and form a diffraction surface, and lens arrays to direct and focus light for uniform image brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If zero-order light is blocked to achieve uniform illumination, then illumination uniformity is improved, but light efficiency is worsened
Solution Approach 1:
The patent converts the harmful zero-order light (which causes illumination nonuniformity) into a beneficial component by projecting it through an optical tunnel and combining it with background image light. This transforms the problematic light that needed to be blocked into a useful illumination source that enhances both uniformity and efficiency
Solution Approach 2:
The patent introduces an optical tunnel as an intermediary component to transport zero-order light from the phase light modulator to the spatial light modulator. This intermediary structure enables the zero-order light to be properly directed and combined with background image light, resolving the contradiction between uniformity and efficiency
2Loss of energy
If zero-order light is projected through optical tunnel and combined with background image light, then light efficiency is improved, but device complexity is worsened
Solution Approach 1:
The patent makes the optical tunnel serve multiple functions: it transports zero-order light, defines the light path, and enables the combination of zero-order light with background image light. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while maintaining improved light 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
Achieves uniform illumination across the projected image, increasing brightness and efficiency by distributing light evenly without blocking zero-order light, enhancing image quality perceived by the human visual system.
Implementation Method 1
a phase light modulator (PLM) to modulate incident light to produce background image illumination comprising background image light and zero-order light
Implementation Method 2
a first lens array to project the background image light towards a second lens array; projecting, through an optical tunnel, the zero-order light towards an embedded lens
Implementation Method 3
focusing optics to focus light comprising the background image light and the zero-order light towards a spatial light modulator (SLM)
Data Source
AI summary
A method includes modulating, by a phase light modulator (PLM), incident light to produce background image illumination comprising background image light and zero-order light that is directed towards a first lens array; projecting, by the first lens array, the background image light towards a second lens array; projecting, through an optical tunnel extending between the first lens array and the second lens array, the zero-order light towards an embedded lens in the second lens array; projecting, by the second lens array, the background image light towards focusing optics; projecting, by the embedded lens, the zero-order light towards the focusing optics; focusing, by the focusing optics, light comprising the background image light and the zero-order light towards a spatial light modulator (SLM); and modulating, by the SLM, the focused light to project an image.