Projection Lens Layout for Compact Micro-Projection Optics
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Solution Overview
Problem
Current micro-projection lenses are too complex and bulky, and the light-emitting chips used with them are large in size, making the projection devices inconvenient to carry and not meeting miniaturization requirements.
Innovation Solution
A projection lens design with a simple optical structure comprising a front lens group, a rear lens group, and a stop, where the front lens group has a focal length of 40 mm < f11 < 60 mm and the rear lens group has a focal length of 2 mm < f22 < 12 mm, with specific air space ratios and focal lengths for each lens, allowing it to be paired with a small-sized light-emitting chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional optical structures are used for micro-projection lenses, then imaging quality can be maintained, but the lens becomes too complex and bulky to satisfy miniaturization requirements
Solution Approach 1:
The projection lens is divided into distinct functional groups: a front lens group with specific positive focal length characteristics and a rear lens group with different focal length characteristics. This segmentation allows each group to be optimized independently for miniaturization while maintaining overall imaging quality, resolving the contradiction between reduced volume and structural complexity.
Solution Approach 2:
The patent specifies precise focal length parameter ranges for the front lens group (f1 satisfying 0.04 < f1/|f| < 0.06) and rear lens group (f2 satisfying 0.02 < f2/|f| < 0.12), where f is the total focal length. By controlling these parameter ratios rather than absolute values, the design achieves scalability and miniaturization while preserving optical performance, thus reducing volume without excessive complexity.
2Ease of operation
If large-sized light-emitting chips are used with current miniature projection lenses, then imaging performance can be achieved, but the projection device becomes inconvenient to carry
Solution Approach 1:
The patent establishes specific parameter ranges for the light-emitting chip size relative to the projection lens focal length (chip diagonal d satisfying 0.015 < d/f < 0.035). By defining this parameter relationship, the design enables scaling down of the light-emitting chip to match miniaturized lens systems, improving portability while maintaining adequate imaging performance through controlled parameter relationships.
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 design results in a compact projection lens that can be easily carried, reducing volume and weight while maintaining high imaging quality, and is compatible with small-sized displays like a 0.16-inch DMD, facilitating miniaturization and portability.
Implementation Method 1
a front lens group, a rear lens group and a stop, wherein the stop is located between the front lens group and the rear lens group
Data Source
AI summary
Embodiments of the present disclosure provides a projection lens and a projecting device; wherein, the projection lens comprises a front lens group, a rear lens group and a stop, sequentially from an object side to an image side along the same optical axis, wherein the stop is located between the front lens group and the rear lens group; wherein the front lens group has a focal length of f11 satisfying: 40 mm<f11<60 mm; the rear lens group has a focal length of f22 satisfying: 2 mm<f22<12 mm.