Adjustable Convergence Mechanism for Projector DMD Alignment

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Solution Overview

Problem

Conventional digital projectors face challenges in adjusting the convergence of red, green, and blue DMD sub-assemblies due to their deep location within the projector, making it difficult and time-consuming to correct color separation issues caused by environmental changes and vibrations without accessing the light engine.

Innovation Solution

An adjustable convergence mechanism is introduced, where the red channel subassembly remains fixed, and the green and blue channel sub-assemblies are equipped with motorized or manual convergence mechanisms, including high precision stepper motors or piezo-actuators, and wedge locking mechanisms, allowing for precise adjustment of the DMD positions without accessing the light engine.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the light engine is located deep inside the projector, then the optical path is stable and compact, but convergence correction becomes difficult and time-consuming

Engineering Contradiction:
Improveoptical path stabilityVSAvoidconvergence correction accessibility
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent introduces an intermediary convergence adjustment mechanism that transmits adjustment forces from the accessible rear region through the optical path to the DMDs in the light engine. This mediator mechanism allows service personnel to correct convergence issues without disassembling the light engine, thus maintaining optical stability while enabling easy repair.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the DMDs are positioned deep in the light engine, then the projector structure is compact, but field alignment requires light engine disassembly

Engineering Contradiction:
Improveprojector structure compactnessVSAvoidmaintenance time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent adds a new dimensional aspect to the adjustment system by implementing a rear-accessible convergence mechanism that operates perpendicular to the main optical path. This allows adjustment forces to be applied from the rear region through transmission mechanisms, enabling field alignment without disassembling the light engine and significantly reducing maintenance time.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If convergence adjustment mechanisms are added to adjust DMD positions, then color convergence can be corrected, but device complexity increases

Engineering Contradiction:
Improvecolor convergence accuracyVSAvoidconvergence mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical adjustment systems with a more elegant transmission mechanism that uses the existing structural elements of the projector. The convergence adjustment mechanism leverages the projector's optical path and structural framework to transmit adjustment forces, thereby achieving precise color convergence correction without significantly increasing overall device complexity.

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

Enables quick and precise field alignment of color channels, reducing the complexity of convergence correction and improving thermal stability by providing additional cooling space, thus maintaining image quality and reducing maintenance time.

Implementation Method 1

motorized or manual convergence mechanisms, including high precision stepper motors or piezo-actuators

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

wedge locking mechanisms

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2280551B1An adjustable convergence mechanism for projection displays
Publication Date: 2016.08.24 CHRISTIE DIGITAL SYSTEMS USA INC
  • EP2280551B1 patent drawingFigure 1~2
  • EP2280551B1 patent drawingFigure 3~4
  • EP2280551B1 patent drawingFigure 5~6

AI summary

A light engine for use in a projector, comprising an adjustable convergence mechanism for fine adjusting the relative positions of red, green and blue channel sub-assemblies. In one embodiment, motors are mounted on fixed elements of the sub-assemblies for driving movable elements thereof, including imaging devices thereof such as digital micromirror devices. In another embodiment, manual adjustment screws are provided in place of the motors, and wedge locking mechanisms are provided for driving and locking the position of the movable elements imaging devices mounted thereon.