Adjustable Mirror Actuator for Trapezoidal Distortion Correction
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Solution Overview
Problem
Projection image display apparatuses that project light obliquely suffer from significant trapezoidal distortion, which is difficult to correct without compromising image resolution or increasing the size of the projector, especially when the incident angle of projection light increases, leading to larger reflecting mirrors and overall projector size.
Innovation Solution
A compact projection image display apparatus with a lens unit, a first mirror for converging light, a second mirror for reflecting light, and a mirror actuator to adjust the tilt of the second mirror, allowing for miniaturization of the mirror and actuator, thus maintaining a compact projector size while correcting trapezoidal distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an angle-adjustable reflecting mirror is provided on a rear side of the projection lens to correct trapezoidal distortion, then the distortion can be reduced, but the reflecting mirror needs to have a larger area as the tilting angle of projection light is increased, which leads to upsizing of the reflecting mirror and the overall projector
Solution Approach 1:
The reflecting mirror is divided into a first reflecting mirror and a second reflecting mirror. The first reflecting mirror has a smaller area and is positioned to receive light from the lens, while the second reflecting mirror receives light from the first mirror. This segmentation allows each mirror to be smaller than a single large mirror would need to be, solving the contradiction between distortion correction capability and mirror size.
2Manufacturing precision
If signal processing is used to correct trapezoidal distortion by adjusting the image drawn on an imager, then the distortion can be eliminated, but the resolution of the projected image deteriorates significantly
Solution Approach 1:
The patent replaces signal processing (software/digital method) with a mechanical/optical method using reflecting mirrors. Instead of correcting distortion through digital image adjustment that degrades resolution, the system uses physical mirror reflection to redirect light paths, achieving distortion correction while preserving the original image resolution from the imager.
3Manufacturing precision
If the installation state of the projector is adjusted to correct trapezoidal distortion, then the distortion can be reduced, but only a slight change in the installation state greatly changes the position of the projected image, making it extremely difficult to let the projected image contained in a screen surface
Solution Approach 1:
The system introduces adjustable reflecting mirrors that can dynamically change the light path angle independently of the projector's installation position. This allows distortion correction without requiring precise installation adjustments, maintaining stable projected image positioning on the screen while correcting trapezoidal distortion through mirror angle adjustment.
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 enables smooth correction of trapezoidal distortion without deteriorating image resolution and prevents the upsizing of the projector, allowing for precise image projection on a screen surface while maintaining a compact design.
Implementation Method 1
a first mirror (30) having a reflecting surface into which the light passing through the lens unit (20) is entered and by which the light is converged
Implementation Method 2
a second mirror (40) for reflecting the light reflected by the first mirror (30)
Data Source
AI summary
A projection image display apparatus includes a lens unit into which light modulated in accordance with an image signal is entered, a first reflecting mirror having a reflecting surface into which the light passing through the lens unit is entered and by which the light is converged, a second reflecting mirror for reflecting the light reflected by the first reflecting mirror, and a mirror actuator for changing a tilt angle of the second reflecting mirror with respect to the light.