Pico-projector Lens Unit Thermal Focal Length Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pico-projector lenses experience significant changes in focal length due to internal heat generation, leading to performance deterioration.
Innovation Solution
A projection lens unit comprising a lens array with specific refractive powers, where plastic lenses are divided into groups with opposite signs and similar absolute values of effective focal lengths, and a glass lens is used to maintain stable focal length against temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plastic lenses are used to reduce manufacturing cost and weight, then manufacturing cost and weight are reduced, but focal length stability deteriorates due to heat generation
Solution Approach 1:
The patent applies composite materials by combining plastic lenses (1st to 4th lenses) with a glass lens (5th lens) in the lens array. The plastic lenses provide cost and weight advantages, while the glass lens provides thermal stability. This composite structure allows the system to achieve both low manufacturing cost and reliable focal length stability under heat generation conditions.
2Weight of moving object
If plastic lenses are used to decrease weight, then weight is decreased, but focal length stability deteriorates due to heat generation
Solution Approach 1:
The patent applies composite materials by combining plastic lenses (1st to 4th lenses) with a glass lens (5th lens) in the lens array. The plastic lenses provide weight advantages, while the glass lens provides thermal stability. This composite structure allows the system to achieve both low weight and reliable focal length stability under heat generation conditions.
3Ease of manufacture
If all lenses are made of plastic to reduce cost, then manufacturing cost is reduced, but image quality deteriorates due to lateral chromatic aberration
Solution Approach 1:
The patent applies composite materials by combining plastic lenses (1st to 4th lenses) with a glass lens (5th lens) in the lens array. The plastic lenses provide cost advantages, while the glass lens provides superior optical properties that reduce lateral chromatic aberration and improve overall image quality. This composite structure allows the system to achieve both low manufacturing cost and high image quality.
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 effectively minimizes focal length changes caused by heat, ensuring a clear and stable image projection despite temperature variations.
Implementation Method 1
a 1st lens with negative (−) refractive power, a 2nd lens with positive (+) refractive power, a 3rd lens with negative (−) refractive power, a 4th lens with negative (−) refractive power, and a 5th lens with positive (+) refractive power
Data Source
AI summary
A projection lens unit for a pico-projector includes a plurality of plastic lenses and a single glass lens to minimize a change in focal length due to the heat generated inside the pico-projector. The lens array includes:a 1st lens with negative (−) refractive power, a 2nd lens with positive (+) refractive power, a 3rd lens with negative (−) refractive power, a 4th lens with negative (−) refractive power, and a 5th lens with positive (+) refractive power, wherein the 1st to 5th lenses are arranged in order from a screen upon which an image is projected, the 1st to 4th lenses are plastic lenses and the 5th lens is a glass lens.