Projection Lens Asymmetric Optical Axis Compact Design
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Solution Overview
Problem
Conventional projection lenses face challenges in achieving high image quality and small size due to the offset of the light valve relative to the optical axis, which limits the reduction of the optical system's size and results in reduced image brightness when attempting to cut off lens portions for size reduction.
Innovation Solution
The projection lens design incorporates a first lens group with a first optical axis, a second lens group with a second optical axis inclined relative to the first, and a third lens group, allowing for an offset greater than 100% of the light valve while maintaining image quality by cutting less of the lens's clear aperture when reducing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the light valve offset is increased to greater than 100% to accommodate ceiling or table mounting, then the projection apparatus can be mounted on ceilings or tables, but the optical system size becomes harder to reduce
Solution Approach 1:
The patent applies asymmetry by introducing an inclined optical axis for the second lens group that is not collinear with the first optical axis. This asymmetric configuration allows the light valve to be positioned with an offset less than 100% while still achieving the necessary image projection geometry for ceiling or table mounting, thereby reducing the overall optical system size while maintaining mounting flexibility.
2Volume of moving object
If a portion of the projection lens is cut off to reduce the optical system size, then the optical system size is reduced, but the clear aperture of the image beam is cut off too much and image brightness is reduced greatly
Solution Approach 1:
The asymmetric optical axis configuration allows the lens aperture to be optimized for both compact size and sufficient light transmission. By tilting the second optical axis, the system achieves the required projection geometry with a smaller lens diameter, eliminating the need to cut off large portions of the lens aperture while maintaining adequate image brightness.
3Volume of moving object
If the offset of the light valve is reduced to less than 100%, then the optical system size can be reduced, but the image beam projection geometry becomes more difficult to achieve
Solution Approach 1:
The patent resolves this contradiction by introducing an asymmetric optical axis configuration where the second lens group's optical axis is inclined relative to the first. This asymmetric design enables the light valve to be positioned with an offset less than 100% while still achieving the necessary projection geometry for the image beam to be correctly directed onto the projection surface.
Solution Approach 2:
The patent introduces a dimensional change by tilting the optical axis from a linear arrangement to an inclined three-dimensional configuration. This allows the system to achieve the required projection geometry with a smaller light valve offset by utilizing the angular dimension, thereby reducing the overall optical system size.
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 a smaller projection lens and apparatus with improved image quality and brightness, as the offset of the light valve relative to the optical axis is less than 100%, allowing for more effective reduction in size without compromising image quality.
Implementation Method 1
The second lens group has a second optical axis, and the second optical axis is inclined with respect to the first optical axis
Data Source
AI summary
A projection lens for projecting an image beam is provided. The image beam is converted by a light valve from an illumination beam irradiating the light valve. The projection lens includes a first lens group, a second lens group, and a third lens group. The first lens group is disposed on a transmission path of the image beam, and has a first optical axis. The second lens group is disposed on both a transmission path of the illumination beam and the transmission path of the image beam, and between the light valve and the first lens group. The second lens group has a second optical axis. The second optical axis is inclined with respect to the first optical axis. The third lens group is disposed on the transmission path of the image beam, and between the first lens group and the second lens group. A projection apparatus is also provided.