Projection Optical System Lateral Chromatic Aberration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional projection optical systems with refractive surfaces suffer from lateral chromatic aberration, leading to image quality deterioration, particularly when pixel shift is employed for higher resolution, resulting in double-line artifacts and reduced resolution feeling.
Innovation Solution
A projection optical system that performs pixel shift by less than a pixel pitch in various directions, with conditional formulae |ΔRG|≦0.5 d and |ΔBG|≦0.5 d, utilizing a configuration with multiple curved mirrors and a refractive lens to minimize lateral chromatic aberration, and incorporating a variable aperture mechanism for dynamic brightness adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel shift is performed to increase apparent resolution, then the volume of information displayed increases, but lateral chromatic aberration causes double-line artifacts and deteriorates image sharpness
Solution Approach 1:
The patent applies parameter changes by precisely controlling the amount of pixel shift to be less than a predetermined value (specifically less than 0.5 times the pixel pitch) and by designing the projection optical system to satisfy specific conditional formulas for lateral chromatic aberration (|ΔRG| < 0.5d and |ΔBG| < 0.5d). This parameter control resolves the contradiction by finding the optimal range where pixel shift increases apparent resolution while keeping lateral chromatic aberration below the threshold that causes visible double-line artifacts.
2Device complexity
If a refractive optical system is used for image projection, then the system structure is simplified, but lateral chromatic aberration occurs and deteriorates image sharpness
Solution Approach 1:
The patent applies local quality by using a reflective optical system (mirrors) specifically for the main projection path to eliminate lateral chromatic aberration, while potentially using refractive elements only where necessary and with specific designs that minimize chromatic effects. This localized approach to optical design resolves the contradiction by making the optical system chromatic-aberration-free in the critical projection regions while maintaining overall structural simplicity.
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 effectively suppresses lateral chromatic aberration, maintaining high image quality and resolution while preventing double-line artifacts, and achieving cost-effective and compact projection optical systems.
Implementation Method 1
utilizing a configuration with multiple curved mirrors
Implementation Method 2
utilizing a configuration with multiple curved mirrors and a refractive lens
Data Source
AI summary
A projection optical system that performs enlargement projection of an image on a display device surface formed of a plurality of pixels onto a screen surface, in which pixel shift by less than a pixel pitch is performed on the screen surface in a vertical direction, a horizontal direction, an oblique direction, or a vertical and horizontal directions, and in which conditional formulae (1) and (2) below are fulfilled over the entire image range: (1)|ΔRG|≦0.5 d and (2)|ΔBG|≦0.5 d, where d represents the amount of pixel shift (>0), ΔRG represents lateral chromatic aberration in the direction of pixel shift of colored light R having a wavelength of 640 nm with respect to colored light G having a wavelength of 546 nm, and ΔBG represents lateral chromatic aberration in the direction of pixel shift of colored light B having a wavelength of 450 nm with respect to the colored light G having a wavelength of 546 nm.