Compact Image Offset Projection Lens Design
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Solution Overview
Problem
Conventional projection display systems face challenges in achieving high image offset with a small form factor and short throw ratio, leading to issues such as image obstruction and keystone effects, particularly in compact environments like conference rooms and portable applications, where traditional methods require larger optics or compromise on image quality.
Innovation Solution
The system employs a projection lens with a display panel and optical elements that introduce image offset by decentering and tilting lens groups, along with an optical shifter that adjusts the optical path in the negative z-direction, allowing for substantial image offset without increasing the projector's thickness or throw ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional projection systems use traditional lens arrangements to achieve image offset, then image positioning is improved, but the system size and throw ratio increase
Solution Approach 1:
The projection system is divided into distinct functional modules: a display panel for light emission, a first lens group for collimating light and introducing initial offset, and a second lens group for focusing the image. This segmentation allows each component to be optimized independently, achieving high image offset with a compact overall structure.
Solution Approach 2:
The first lens group acts as an intermediary between the display panel and the second lens group. It collimates the light from the display panel and introduces image offset before the light reaches the second lens group, which then focuses the offset image. This intermediary function enables high image offset without requiring the final image plane to be physically distant from the projection lens.
2Measurement precision
If conventional systems increase lens size to achieve high image offset, then image positioning capability is improved, but manufacturing cost increases
Solution Approach 1:
The first lens group elements are offset relative to each other by specific amounts (no more than 20% of the display panel height) to introduce the required image offset. This localized offset arrangement allows the system to achieve high image offset (100% or more) without requiring all lens elements to be large or precisely positioned, thereby reducing manufacturing complexity and cost.
3Volume of moving object
If the projection lens is positioned close to the display panel to reduce form factor, then compactness is improved, but image quality and focus capability deteriorate
Solution Approach 1:
The optical system is designed with adjustable degrees of freedom, including the ability to offset individual lens elements within the first lens group and to adjust the positioning of the second lens group. This dynamic adjustability allows the system to maintain optimal focus quality even when the overall form factor is reduced and the lens groups are positioned closer together.
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 approach enables high image offset with a smaller, lower-cost projection lens, maintaining a compact form factor and short throw ratio, while minimizing the physical offset between the display panel and projection lens, thus addressing the limitations of traditional systems in achieving desirable image positioning and quality.
Implementation Method 1
a first lens group substantially collimating light from the display panel and introducing image offset in a first direction relative to the optical axis
Implementation Method 2
an optical shifter shifting the optical path in a direction opposite the image offset
Implementation Method 3
a second lens group focusing an image of the display panel on an image plane
Data Source
AI summary
A projection lens for projecting images with high degrees of image offset while limiting the physical offset of the projection lens elements. The projection lens arrangement limits the displacement of the optical elements relative to the optical axis of the display panel and enables a very thin, efficient projector.