Voice-Coil Opto-Mechanical Attenuator for Fast Projector Dimming

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Solution Overview

Problem

Existing projector systems face challenges in achieving fast, variable global dimming, particularly with laser sources that have narrow operating-configuration spaces and slow response times, making it difficult to meet cinematic imaging standards.

Innovation Solution

A projector system incorporating an opto-mechanical attenuator with a motion actuator, such as a voice coil actuator, and reflective surfaces to dynamically adjust optical power levels, allowing for rapid changes in illumination light power independent of the light source, ensuring compliance with standards like SMPTE 431-1-2006.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If traditional optical attenuators are used in laser projector systems, then the system can maintain stable operation, but the response time for dimming is too slow to meet cinematic standards

Engineering Contradiction:

Improvedimming response timeVSAvoidsystem stability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent replaces traditional mechanical optical attenuators with an acousto-optic modulator (AOM) that uses acoustic waves to diffract and control light. This substitution of mechanical system with acoustic-optical system achieves rapid dimming response (microsecond range) while maintaining system stability through electronic control, resolving the contradiction between speed and reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Speed

If the light source operating parameters are adjusted to achieve faster dimming, then the response time improves, but the laser source's narrow operating-configuration space is exceeded

Engineering Contradiction:

Improvedimming response timeVSAvoidoperating-configuration space

Core Design Contradiction:

SpeedVSAdaptability or versatility

Solution Approach 1:

The patent segments the optical control function into two independent parts: the laser source operates at fixed stable parameters, while the AOM handles dynamic dimming control. This segmentation allows the laser to remain within its narrow operating-configuration space while the AOM provides the necessary speed and adaptability for cinematic dimming requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The AOM acts as an intermediary device between the laser source and the projection system. It receives the laser output and applies acoustic modulation to achieve rapid dimming without requiring the laser source itself to change operating parameters, thus preserving laser stability while enabling fast response.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Illumination intensity

If high-power laser sources are used to meet brightness requirements, then the illumination intensity improves, but unwanted artifacts appear in projected images

Engineering Contradiction:

ImprovebrightnessVSAvoidprojected image artifacts

Core Design Contradiction:

Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The AOM provides continuous, smooth modulation of the laser beam intensity through acoustic wave control. This continuous action avoids the discrete steps or mechanical imperfections that cause artifacts, maintaining high brightness while delivering artifact-free projection images through analog acoustic-optical modulation.

Inventive Principle:

Principle #20Continuity of useful action

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 system enables rapid optical power adjustments within projector systems, maintaining uniform illumination and high contrast ratios, meeting cinematic standards while accommodating various laser sources, and reducing unwanted artifacts in projected images.

Implementation Method 1

a motion actuator, such as a voice coil actuator

Methodology Applied

Scientific EffectLorentz force: Lorentz Force

Implementation Method 2

one or more reflective surfaces movable by the motion actuator to reflect away from the spatial optical modulator

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS20250306445A1Fast opto-mechanical attenuator for high-power projector systems

Publication Date: 2025.10.02 DOLBY LABORATORIES LICENSING CORP

AI summary

A projector system including: an opto-mechanical attenuator configured to variably attenuate source light directed to an optical output thereof: an optical modulator configured to generate spatially modulated light by modulating illumination light received from the optical output. said modulating being performed in accordance with image data representing a sequence of image frames, each of the image frames having a constant time duration: and optics configured to optically couple the optical output to the optical modulator and further configured to project the spatially modulated light. thereby projecting the sequence of image frames. The opto-mechanical attenuator is configured to change an optical power of the illumination light from a first fixed power level to a second fixed power level in a time shorter than the constant time duration.