Projection Optical System with Catoptric Aberration Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing projection optical systems for projectors require a large number of lenses to achieve a broad magnification range, leading to increased complexity and size, particularly when trying to maintain a compact and proximate projection capability.
Innovation Solution
A projection optical system comprising a dioptric system with multiple lenses and a catoptric system with specific reflection surfaces, where the catoptric system includes a first concave, a second curved, and a third convex aspherical reflection surface, arranged in a specific order to satisfy certain focal distance and power conditions, allowing for compact and proximate projection while minimizing the number of lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dioptric system with multiple lenses is used to achieve a broad magnification range, then the magnification range is improved, but the device complexity and number of lenses increase
Solution Approach 1:
The projection optical system is divided into two distinct subsystems: a dioptric system with multiple lenses for magnification and a catoptric system with three reflection surfaces for aberration correction. This segmentation allows each subsystem to be optimized independently, achieving broad magnification range without proportionally increasing overall complexity
Solution Approach 2:
The patent replaces part of the refractive dioptric system with a catoptric system using reflection surfaces. By substituting some lens functions with mirror-based catoptric elements, the system reduces the number of lenses needed while maintaining the broad magnification range through the combined optical paths
2Illumination intensity
If the F number is brightened to correspond to a broad magnification range, then the brightness is improved, but the number of lenses increases to ten-odd lenses
Solution Approach 1:
The optical system segments the brightness control function between the dioptric system (which manages light gathering and F number) and the catoptric system (which manages light distribution and aberration correction). This allows achieving bright images across broad magnification ranges without requiring ten-odd lenses, as the catoptric system efficiently redirects light paths
Solution Approach 2:
The catoptric system with three reflection surfaces serves multiple functions simultaneously: it corrects aberrations, manages light distribution across different magnification ranges, and maintains brightness levels. This multi-functionality eliminates the need for additional dedicated lenses for each function, reducing the total lens count from ten-odd to a manageable number
3Volume of moving object
If a compact and proximate projection system is designed, then the size is reduced, but the back focus length is limited
Solution Approach 1:
The catoptric system with three reflection surfaces introduces a folded optical path that utilizes the lateral dimension rather than extending the optical axis linearly. This allows the system to achieve a long back focus length in a compact form factor by redirecting light through multiple reflections, effectively packing a long optical path into a short physical distance
4Manufacturing precision
If aspherical surfaces are used in the catoptric system, then the aberration correction is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The aspherical surfaces in the catoptric system are strategically positioned and designed with specific local curvature characteristics optimized for their particular locations in the optical path. Each aspherical surface corrects specific aberrations relevant to its position, allowing for effective aberration correction while managing manufacturing complexity through localized optimization rather than uniform high precision across all surfaces
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
This configuration enables compact and proximate projection while maintaining long back focus and correcting aberrations, reducing the overall size and complexity of the projector while achieving a high magnification range and numerical aperture.
Implementation Method 1
a dioptric system including a plurality of lenses (L1 to L7) and having positive powers
Implementation Method 2
The catoptric system includes first, second, and third catoptric systems installed in order from a side of the dioptric system along an optical path of light emitted from the dioptric system
Data Source
AI summary
A projection optical system capable of performing compact and proximate projection and a projector including the projection optical system. The projection optical system includes a first optical group which is a dioptric system and a second optical group which is a catoptric system. The second optical group includes a first catoptric system to a third catoptric system that have a first reflection surface with a concave surface shape, a second reflection surface with a curved surface shape, and a third reflection surface with a convex surface shape. The first catoptric system to the third catoptric system satisfy Conditional Expression (1) for focal distances. Image light emitted from the first optical group is reflected by the second optical group to be projected to a projection surface.