Rotating Optical System for Front Projection Trapezoidal Distortion

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Solution Overview

Problem

Front projection display devices suffer from trapezoidal distortion when the installation position or projection angle is not optimal, leading to a decrease in image sharpness due to the inability to perform dot-by-dot display after correcting distortion through two-dimensional image processing.

Innovation Solution

A front projection display device with a rotatable image forming optical system and reflection members that correct trapezoidal distortion by adjusting the pitch and yaw angles, utilizing a first optical system with lenses and reflection members that can rotate in conjunction with the optical axis, and a second driving unit for precise control to maintain image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If two-dimensional image processing is used to correct trapezoidal distortion, then the projected image shape is corrected, but image sharpness decreases and dot-by-dot display cannot be performed

Engineering Contradiction:

Improveprojected image shapeVSAvoidimage sharpness

Core Design Contradiction:

ShapeVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical/image processing approach (two-dimensional image processing) with an optical approach (rotating the image forming optical system). By physically rotating the optical system including lenses and reflection members, the projection angle is adjusted to match the screen orientation, correcting trapezoidal distortion optically while preserving pixel correspondence and image sharpness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Shape

If the projection angle is adjusted to match the screen, then trapezoidal distortion is reduced, but the optical system requires complex rotation mechanisms

Engineering Contradiction:

Improveprojected image shapeVSAvoidoptical system structure

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The patent merges the rotation functions of multiple optical components (lenses and reflection members) into a single integrated rotation mechanism. The image forming optical system is designed so that all necessary components rotate together as one unit, controlled by a single driving unit, thereby reducing mechanical complexity while achieving the required angle adjustment.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces dynamic adjustability to the optical system by enabling rotation of the entire image forming optical system. This dynamic capability allows the system to adapt to different screen orientations and projection angles, correcting trapezoidal distortion without requiring multiple fixed optical paths or complex switching mechanisms.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If a wide-angle optical system is used, then the total angle of view is increased, but trapezoidal distortion becomes more pronounced

Engineering Contradiction:

Improvetotal angle of viewVSAvoidprojected image shape

Core Design Contradiction:

Adaptability or versatilityVSShape

Solution Approach 1:

The patent combines a wide-angle optical system with dynamic rotation capability. The optical system is designed to provide a total angle of view of 90 degrees or more for versatility, while the rotation mechanism allows real-time adjustment of the projection angle to compensate for and correct trapezoidal distortion, enabling both wide coverage and accurate projection geometry.

Inventive Principle:

Principle #15Dynamics

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 solution allows for optical correction of trapezoidal distortion, maintaining image sharpness and enabling dot-by-dot display, even with wide-angle views, by precisely adjusting the optical system and reflection members to align the optical axis with the projection surface.

Implementation Method 1

a first reflection member that reflects the light emitted from the light valve toward the first optical system, the first optical system and the first reflection member are configured to be rotatable in a pitch direction, and the first reflection member rotates by a pitch angle θ/2 in conjunction with rotation of the first optical system by a pitch angle θ

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

a light valve that modulates light based on image data and emits the light

Methodology Applied

Scientific EffectLight modulation:

Implementation Method 3

an image forming optical system that projects an optical image of the light modulated by the light valve onto a projection surface

Methodology Applied

Scientific EffectOptical projection: Lens

Data Source

PatentUS11378873B2Projection display device

Publication Date: 2022.07.05 FUJIFILM CORP

AI summary

A projection display device of a front projection type includes a light valve that modulates light based on image data and emits the light and an image forming optical system that projects an optical image of the light modulated by the light valve onto a projection surface, in which the image forming optical system includes a first optical system that includes at least one lens and a first reflection member that reflects the light emitted from the light valve toward the first optical system, the first optical system and the first reflection member are configured to be rotatable in a pitch direction, and the first reflection member rotates by a pitch angle θ/2 in conjunction with rotation of the first optical system by a pitch angle θ.