Projection Optical System with Hybrid Refractive-Reflective Design
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Solution Overview
Problem
Conventional projection optical systems face challenges in achieving a compact design while maintaining high resolution and uniform brightness, often requiring precise alignment of multiple aspheric surfaces which increases cost and complexity, and struggle with chromatic aberration compensation.
Innovation Solution
A projection optical system comprising a first optical system with lens groups having positive, positive, and negative refractive powers in sequence, combined with a reflective optical system using a mirror with positive refractive power, which reduces lens diameter and allows for independent aberration correction, and is telecentric to ensure uniform brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple aspheric surfaces are used to maintain imaging performance and achieve wide angle of view, then imaging quality is improved, but manufacturing precision requirements increase and cost increases
Solution Approach 1:
The patent applies parameter changes by transforming the complex multi-aspheric surface design into a system with fewer surfaces where at least one surface is spherical. This changes the geometric parameters of the optical surfaces, reducing manufacturing precision requirements while maintaining imaging performance through optimized optical paths and lens arrangements.
2Volume of stationary object
If a compact projection optical system is designed, then device size is reduced, but chromatic aberration compensation becomes difficult
Solution Approach 1:
The patent employs composite materials principle by combining different types of optical elements (lenses with different refractive indices, reflective surfaces, and refractive surfaces) in a hybrid optical system. This composite structure enables effective chromatic aberration compensation within a compact form factor by leveraging the complementary optical properties of each element type.
3Length of moving object
If projection distance is reduced, then device compactness is improved, but shadow reflection on screen occurs
Solution Approach 1:
The patent applies dimensionality change by transitioning from a conventional front-projection arrangement to a rear-projection configuration. This spatial reorganization places the projector behind the screen, changing the projection direction and eliminating shadow reflection issues while achieving short projection distances in a compact setup.
4Volume of stationary object
If lens diameter is reduced, then device size is minimized, but resolution and brightness uniformity deteriorate
Solution Approach 1:
The patent applies segmentation by dividing the optical system into multiple functional zones with different lens groups (positive and negative power groups) and reflective surfaces. Each segment is optimized for specific functions, allowing the overall lens diameter to be reduced while maintaining resolution and brightness uniformity through coordinated operation of segmented optical elements.
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 results in a more compact, cost-effective projection system with improved resolution and reduced production errors, capable of correcting distortion and maintaining uniform brightness across the image plane.
Implementation Method 1
a first optical system (013) which forms a second image conjugate to a first image... the first optical system comprises a stop (012) and at least one optical element with a positive refractive power and at least one optical element with a negative refractive power
Implementation Method 2
a second optical system (015) which comprises a reflective optical element (014) reflecting light from the second image to project a third image conjugate to the second image onto a projection surface
Data Source
AI summary
A projection optical system including a first optical system configured to form a second image conjugate to a first image and a second optical system configured to include a reflective optical element which reflects light from the second image and to project a third image conjugate to the second image onto a projection surface is provided, wherein the first optical system includes a stop and at least one optical element with a positive refractive power and at least one optical element with a negative refractive power which are provided between the stop and the second image, and an optical element with a strongest positive refractive power in the at least one optical element with a positive refractive power is provided between the stop and an optical element with a strongest negative refractive power in the at least one optical element with a negative refractive power.