Projection Optical System with Compact Lens Group for Wide Zoom
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Solution Overview
Problem
Existing projection optical systems for projectors face challenges in achieving a wide zooming range while maintaining a compact design and minimizing the number of lenses, particularly in portable devices where the combination of refraction optical systems and concave mirrors results in large and complex systems that are difficult to manufacture and assemble accurately.
Innovation Solution
A projection optical system comprising a first optical group with a 1-1 lens group and a 1-2 lens group, where the 1-2 lens group includes three lenses (F1, F2, and F3) with specific configurations, including a positive lens, a negative meniscus lens, and a negative lens, and an aperture diaphragm within the 1-1 lens group to adjust light flux and prevent chromatic aberration, allowing for a wide zooming range while keeping the system compact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a refraction optical system and concave mirror are combined to achieve ultra-wide viewing angle, then the viewing angle is improved, but the entire length becomes very long and the system becomes complex
Solution Approach 1:
The patent applies parameter changes by optimizing the curvature radii, focal lengths, and spacing of lens elements in the refraction optical system. Specifically, the first through fourth lens groups have carefully selected focal lengths and curvature radii that enable ultra-wide viewing angles while maintaining a compact overall length. The aspherical surfaces of the lenses are also optimized with specific curvature parameters to achieve the desired angular performance without increasing system length.
2Illumination intensity
If a refraction optical system and concave mirror are combined to achieve ultra-wide viewing angle, then the viewing angle is improved, but the device complexity increases making it difficult to manufacture and assemble
Solution Approach 1:
The patent segments the optical system into four distinct lens groups (first through fourth lens groups), each with specific functions. The first lens group handles initial light convergence, the second group manages intermediate image formation, the third group corrects aberrations, and the fourth group finalizes the image. This segmentation allows each group to be optimized independently and assembled systematically, reducing overall complexity despite the ultra-wide viewing angle requirement.
Solution Approach 2:
The patent employs composite optical design by combining refractive lens elements with aspherical surfaces and a reflective concave mirror. The aspherical surfaces are integrated into the lens structure to correct spherical aberration and other optical imperfections. This composite approach achieves ultra-wide viewing angles with controlled system complexity by using mathematically defined aspherical profiles rather than complex multi-element arrangements.
3Length of moving object
If the number of lenses is reduced to make the system compact, then the system size is improved, but the manufacturing precision and assembly accuracy become more difficult to maintain
Solution Approach 1:
The patent applies preliminary action by pre-integrating aspherical surfaces into the lens elements during manufacturing. The aspherical profiles are precisely formed on the lens surfaces before assembly, ensuring that the optical correction for spherical aberration and other distortions is built into the components themselves. This preliminary preparation of optical parameters allows for compact system design while maintaining high manufacturing precision through standardized aspherical lens production techniques.
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 a projector to cover a wide zooming range with a reduced number of lenses, achieving high image quality with small flare and contrast, and is easier to manufacture and assemble, making it suitable for portable devices.
Implementation Method 1
a second optical group which includes a single reflection surface having a concave aspherical shape
Implementation Method 2
a first optical group which has positive power and includes a plurality of lenses
Data Source
AI summary
A projection optical system and that includes a relatively small number of lenses and are able to cover a wide zooming range and a projector. A 1-2 lens group which is a focus lens group is constituted with a lens which includes a single positive lens having a convex surface to the reduction side, a lens which includes a single negative meniscus lens having a convex surface to an enlargement side, and a lens which includes a single negative lens, and the 1-2 lens group is moved at the time of focusing accompanying magnification change.