Projection Lens Frame Light Reflection-Reducing Structure
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Solution Overview
Problem
Existing projection lenses suffer from the generation of stray light, which can cause noise in projected images, particularly due to the reflection of light from lens surfaces and frames.
Innovation Solution
A projection lens design that includes a first lens with a larger diameter than a second adjacent lens, and a frame with a light reflection-reducing structure on its surface facing the first lens. The frame's surface has an uneven shape, and the ratio of the diameters of the first and second lenses is 1.7 or more, effectively scattering return light and reducing stray light generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a frame is positioned outside the second lens to support the optical system, then structural stability is improved, but light reflection from the frame surface generates stray light
Solution Approach 1:
The patent applies anti-reflection coatings on the frame surface to convert the harmful reflective property into a beneficial non-reflective property. The coating layer reduces light reflection by creating optical interference that cancels reflected waves, thereby suppressing stray light generation while maintaining the frame's structural support function.
Solution Approach 2:
The patent changes the optical parameters of the frame surface by applying coatings with specific refractive indices and thicknesses. By controlling the coating thickness to be one-quarter of the wavelength of light and selecting materials with appropriate refractive indices, the frame surface transitions from a high-reflection state to a low-reflection state, effectively reducing stray light.
2Object-generated harmful factors
If lens diameters are designed with a ratio of 1.7 or more between the first and second lenses, then stray light is suppressed through geometric configuration, but manufacturing complexity increases
Solution Approach 1:
The patent specifies a precise parameter range for the diameter ratio between the first and second lenses (1.7 or more). This parameter optimization balances stray light suppression with manufacturing feasibility. By setting a clear numerical threshold, the design provides guidance for manufacturing while achieving the optical performance goal of reducing stray light through geometric configuration.
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 proposed design significantly suppresses the generation of stray light, improving image quality by dispersing reflected light and preventing its concentration, which enhances the clarity and accuracy of projected images.
Implementation Method 1
The first surface has a light reflection-reducing structure... effectively scattering return light and reducing stray light generation
Data Source
AI summary
A projection lens is a projection lens that emits incident light through a plurality of lenses, and includes a first lens that is disposed to be closest to an emission side, a second lens which is adjacent to the first lens and of which a diameter is smaller than a diameter of the first lens, and a frame that includes a first surface and is positioned outside the second lens in a radial direction. The first surface faces the first lens, the first surface has a light reflection-reducing structure, and a value of G1/G2 is 1.7 or more in a case where a diameter of the first lens is denoted by G1 and a diameter of the second lens is denoted by G2.