Dual Spatial Light Modulation for High-Contrast HDR Projection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing projector technologies face challenges in achieving high contrast and peak luminance efficiently while minimizing power consumption, as they often absorb light, require complex computational methods, or produce artifacts like laser speckle and diffraction.

Innovation Solution

A dual-modulation approach using a phase-only spatial light modulator combined with an amplitude modulator, optimized through a Fourier domain method, redistributes light to achieve high dynamic range and peak luminance, applicable to both white and laser illumination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If amplitude spatial light modulators are used to create tones and colors by pixel-selectively blocking light, then image quality is improved, but optical efficiency deteriorates since blocked light is absorbed

Engineering Contradiction:

Improveimage qualityVSAvoidoptical efficiency

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent replaces amplitude modulation (mechanical blocking/absorption) with phase modulation (optical path control). The phase-only spatial light modulator changes the phase of light waves rather than blocking them, achieving image formation through constructive and destructive interference patterns. This substitution eliminates light absorption losses while maintaining image quality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes phase transitions of light waves to achieve image formation. By modulating the phase of light across different regions of the spatial light modulator, the system creates interference patterns that form the desired image. This phase-based approach allows light to be redirected and redistributed without absorption, improving optical efficiency.

Inventive Principle:

Principle #36Phase transitions

2Illumination intensity

If high peak brightness is achieved by boosting the power of the projector light source, then illumination intensity is improved, but power consumption and thermal management complexity increase

Engineering Contradiction:

Improvepeak brightnessVSAvoidpower consumption

Core Design Contradiction:

Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent replaces intensity-based brightness control with phase-based light redistribution. Instead of increasing light source power to achieve peak brightness, the system uses phase modulation to concentrate and redirect existing light energy to specific regions, achieving high peak brightness through efficient energy utilization rather than energy input.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the control parameter from light intensity to light phase. By modulating the phase parameter rather than the intensity parameter, the system achieves high peak brightness through spatial redistribution of light energy. This parameter change allows the same light source power to produce higher peak brightness by concentrating energy where needed.

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If laser light is used for light reallocation, then illumination efficiency is improved, but laser speckle artifacts are generated

Engineering Contradiction:

Improveillumination efficiencyVSAvoidlaser speckle

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent changes the light source parameter from coherent laser light to incoherent or partially coherent light. This parameter change eliminates laser speckle artifacts while maintaining illumination efficiency through phase modulation. The phase-only spatial light modulator can effectively redistribute both coherent and incoherent light, making the system versatile and artifact-free.

Inventive Principle:

Principle #35Parameter changes

4Measurement precision

If very high spatial frequency control of light is implemented, then image resolution is improved, but diffraction artifacts are caused and light modulator demands increase

Engineering Contradiction:

Improveimage resolutionVSAvoiddiffraction artifacts

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent replaces amplitude-based spatial frequency control with phase-based control. Phase modulation allows for smoother transitions and more gradual phase variations across the spatial light modulator, reducing the abrupt discontinuities that cause diffraction artifacts. This substitution enables high spatial frequency control with reduced diffraction effects.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method enables efficient, high-contrast, high-dynamic-range projection systems that eliminate laser speckle and diffraction artifacts, allowing real-time video processing and improved image quality.

Implementation Method 1

Methodology Applied

Scientific EffectPhase modulation: Phase Modulation

Implementation Method 2

eliminate laser speckle and diffraction artifacts

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 3

optimized through a Fourier domain method

Methodology Applied

Scientific EffectFourier transform:

Data Source

PatentUS12574484B2Efficient, dynamic, high contrast lensing with applications to imaging, illumination and projection

Publication Date: 2026.03.10 BARCO VISUAL SOLUTIONS INC

AI summary

A new projector design combines one spatial light modulator that affects only the phase of the illumination, and one spatial light modulator that only affects its amplitude (intensity). The phase-only modulator curves the wavefront of light and acts as a pre-modulator for a conventional amplitude modulator. This approach works with both white light and laser illumination, generating a coarse image representation efficiently, thus enabling, within a single image frame, significantly elevated highlights as well as darker black levels while reducing the overall light source power requirements.