Anamorphic Projection Lens Aspect Ratio Conversion
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Solution Overview
Problem
Existing projection systems face challenges in maintaining telecentricity and light usage efficiency due to the size and complexity of external aspect ratio converters, which degrade image quality and increase the projector's size, and rear-mounted relay systems do not provide exact telecentricity in both cross-sectional planes, leading to inefficient light usage.
Innovation Solution
A projection system with an object-side lens group having different power factors between vertical and horizontal directions, allowing for adjustable aspect ratios and maintaining telecentricity by positioning the diaphragm between the lens group and the focal points, and incorporating a second group that can be retreatedably disposed to reduce aberrations and simplify mechanical adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a front-mounted converter is used to change aspect ratio, then aspect ratio conversion is achieved, but the projector size increases and image quality degrades
Solution Approach 1:
The patent merges the aspect ratio conversion function with the existing projection optical system by integrating an anamorphic lens group into the projector body. This combines the converter functionality with the projection system, eliminating the need for separate external converters and reducing overall system size while maintaining aspect ratio conversion capability.
Solution Approach 2:
The anamorphic lens group is designed to serve multiple functions: it acts as both an aspect ratio converter and part of the projection optical system. This multi-functional design eliminates the need for separate dedicated converters, reducing projector size while maintaining versatility in aspect ratio adjustment.
2Adaptability or versatility
If a rear-mounted relay system is used for aspect ratio conversion, then aspect ratio conversion is achieved, but telecentricity cannot be maintained in both cross-sectional planes simultaneously
Solution Approach 1:
The patent employs an anamorphic lens group with asymmetric optical characteristics that provide different focal lengths in horizontal and vertical directions. This asymmetric design enables simultaneous telecentricity in both cross-sectional planes while achieving aspect ratio conversion, resolving the limitation of conventional symmetric relay systems.
Solution Approach 2:
The patent changes the optical parameters by using an anamorphic lens group with specific focal length relationships (FFPx and FFPy) to achieve telecentricity in both directions. By carefully controlling the focal length parameters and their relationships, the system maintains telecentricity while providing aspect ratio conversion capability.
3Adaptability or versatility
If a rear-mounted relay system is used, then aspect ratio conversion is achieved, but light usage efficiency decreases due to degraded telecentricity
Solution Approach 1:
The anamorphic lens group utilizes asymmetric optical design with different focal lengths in horizontal and vertical directions to maintain proper light cone angles and telecentricity. This asymmetric approach preserves light usage efficiency by ensuring optimal light paths in both directions, preventing the energy loss associated with conventional relay systems.
Solution Approach 2:
By optimizing the focal length parameters (FFPx and FFPy) and their relationships, the patent achieves parameter changes that maintain telecentricity and improve light usage efficiency. The specific parameter relationships ensure that light rays are properly directed, reducing energy loss and improving overall optical efficiency.
4Reliability
If an anamorphic lens group with different power factors is used, then aspect ratio conversion and telecentricity are achieved, but the system becomes more complex
Solution Approach 1:
The patent combines the anamorphic lens group with the existing projection optical system, merging multiple functions into a single integrated system. This reduces overall system complexity by eliminating separate external converters and relay systems, while maintaining telecentricity and aspect ratio conversion capabilities.
Solution Approach 2:
The anamorphic lens group is designed as a multi-functional component that performs aspect ratio conversion, maintains telecentricity, and integrates with the projection system. This universal design reduces the need for multiple separate components, simplifying the overall system while achieving multiple objectives simultaneously.
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 system achieves balanced light usage efficiency and improved image quality by maintaining telecentricity in both directions, reducing aberrations, and simplifying mechanical assembly, while allowing for precise aspect ratio adjustments and efficient image projection.
Implementation Method 1
an object-side lens group disposed between the light modulator and the diaphragm has different power factors between vertical and horizontal directions of the light modulator
Implementation Method 2
a diaphragm that limits a light flux passing therethrough
Data Source
AI summary
An object-side lens group has different power factors between the vertical and horizontal directions of a liquid crystal panel, and a projection system as a whole therefore has different focal lengths between the vertical and horizontal directions and hence different magnification factors between the vertical and horizontal directions, whereby the aspect ratio of an image on the liquid crystal panel can be set at a value different from the aspect ratio of an image projected on a screen. That is, the projection system can convert the aspect ratio, which is the ratio of the width to the height of an image. When the distance between a diaphragm and an extreme end surface of the object-side lens group on the screen side satisfies a predetermined condition, at least a certain degree of telecentricity can be provided both in the vertical and horizontal directions.