DMD Movable Plate Positioning for High-Resolution Projection

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Solution Overview

Problem

Existing image projection apparatuses face challenges in increasing resolution without complicating the projection optical system and reducing the flexibility of design, particularly in accurately and swiftly moving decentered lenses to shift the projection image by distances less than the interval between picture elements.

Innovation Solution

The apparatus incorporates a movable unit with a DMD and a heat sink, where the DMD is mounted on a movable plate supported by a joint plate, allowing precise control of the DMD's position using Lorentz forces generated by interacting coils and magnets, enabling high-speed movement between positions less than the micromirror array interval, thereby enhancing image resolution without complex system modifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If decentered lenses are moved to shift the projection image to increase resolution, then the resolution of the projection image is improved, but the device complexity increases due to additional mechanisms required for moving the lenses

Engineering Contradiction:
Improveresolution of projection imageVSAvoidstructure of projection optical system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical lens shifting mechanism with an optical field shifting approach. Instead of physically moving decentered lenses through complex mechanical mechanisms, the invention shifts the optical field by moving the image generation unit (DMD) relative to the optical axis using a simple movable unit with positioning actuators. This substitution eliminates the need for complex lens moving mechanisms while achieving the same resolution enhancement effect.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If decentered lenses are moved to shift the projection image, then the resolution of the projection image is improved, but the ease of operation deteriorates due to difficulty in controlling lens positions at high speed and with good accuracy

Engineering Contradiction:
Improveresolution of projection imageVSAvoidcontrol of lens positions
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical lens positioning system with an electrical control system for the movable unit. The image generation unit (DMD) is positioned by electrically controlled actuators (voice coil motors or piezoelectric elements) that can rapidly and accurately adjust the DMD's position relative to the optical axis. This electrical control system offers superior speed and precision compared to mechanical lens positioning, enabling high-resolution image generation without operational complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If picture element density in the image generation unit is increased to increase resolution, then the resolution of the projection image is improved, but the manufacturing cost increases

Engineering Contradiction:
Improveresolution of projection imageVSAvoidmanufacturing cost of image generation unit
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the parameter of relative position between the image generation unit and the optical axis rather than changing the picture element density. By shifting the optical field through positional adjustment of the DMD, the system achieves higher effective resolution without increasing the physical density of picture elements in the DMD. This approach maintains the same manufacturing cost for the DMD while achieving enhanced resolution through optical field manipulation.

Inventive Principle:
Principle #35Parameter changes

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 configuration allows for increased resolution of the projection image, maintains system simplicity, and effectively prevents temperature-related malfunctions by efficient cooling of the DMD, achieving higher resolution than conventional systems without reducing image size or aspect ratio.

Implementation Method 1

allowing precise control of the DMD's position using Lorentz forces generated by interacting coils and magnets

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Implementation Method 2

effectively prevents temperature-related malfunctions by efficient cooling of the DMD

Methodology Applied
Scientific EffectHeat dissipation: Heat Sink

Data Source

PatentEP3213147B1Image formation unit and image projection apparatus
Publication Date: 2020.08.12 RICOH CO LTD
  • EP3213147B1 patent drawingFigure 1
  • EP3213147B1 patent drawingFigure 2
  • EP3213147B1 patent drawingFigure 3

AI summary

An image projection apparatus includes a light source, an image generation unit configured to receive light from the light source and generate an image based on the received light, a projection optical system unit configured to project the image generated by the image generation unit, a heat dissipation unit configured to dissipate heat of the image generation unit, and a movable member configured such that a position of the movable member is movable relative to the projection optical system unit, wherein the image generation unit and the heat dissipation unit are mounted on the movable member.