Distribution Mask for Uniform Optical Coating
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Solution Overview
Problem
Existing vapor deposition methods for optical articles with significant curvature or sphericity face challenges in achieving uniform coating thickness due to non-isotropic evaporation cones, leading to disparities in antiglare performance and color distribution.
Innovation Solution
A distribution mask with curved arms is positioned to mask the central portion of optical articles, allowing only the peripheral edges to receive the deposited material, thereby compensating for the difference in distance from the evaporation source and ensuring uniform coating across the article.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rotary support with distributed locations is used to treat multiple optical articles simultaneously, then productivity is improved, but manufacturing precision deteriorates due to non-uniform deposition from the evaporation cone
Solution Approach 1:
A distribution mask is introduced as an intermediary element between the evaporation source and the rotary support. The mask has a specific geometry (wider at the periphery, narrower at the center) that compensates for the non-uniform evaporation cone, redistributing the material flux to achieve uniform deposition across all optical articles regardless of their position on the rotary support.
2Productivity
If the evaporation cone is used to deposit material on optical articles at different distances from the axis of rotation, then productivity is improved, but manufacturing precision worsens because the density of emitted molecules is greater close to the axis than at greater distances
Solution Approach 1:
The distribution mask implements local quality by having different geometrical properties at different locations. The mask width varies radially - wider at the periphery where less material naturally arrives, and narrower at the center where more material is emitted. This local variation in mask geometry compensates for the spatial non-uniformity of the evaporation cone, ensuring uniform deposition across all radial positions.
3Manufacturing precision
If a cap-shaped rotary support is used to minimize density differences in the evaporation cone, then manufacturing precision is improved, but device complexity increases and uniformity is still insufficient
Solution Approach 1:
Rather than making the rotary support itself complex (cap-shaped), the invention uses a separate distribution mask as a mediator. The mask can be a simple planar or slightly curved element with a radially varying width profile, which is much easier to manufacture and adjust than a complex three-dimensional cap-shaped support structure.
Solution Approach 2:
The invention changes the geometrical parameters of the distribution mask (specifically its radial width profile) to compensate for the evaporation cone characteristics. By adjusting the mask width as a function of radial position, the system achieves uniform deposition without requiring complex changes to the rotary support geometry.
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 achieves better uniformity of coating deposition on optical articles with significant curvature or sphericity, enhancing antiglare performance and color distribution consistency.
Implementation Method 1
an emitting source, from which the material to be deposited is evaporated according to an evaporation cone
Implementation Method 2
Installation for vapor deposition of a coating on optical articles
Data Source
AI summary
The invention relates to an apparatus for the vapor deposition of a coating on optical articles, comprising a distribution mask (32) for controlling the vapor deposition of a coating on optical articles that is positioned in the path of some of the molecules emitted by said emitting source in the direction of the rotatable support for optical articles. The distribution mask (32) is fitted with at least one arm (34) positioned so as to mask at least one partial zone (16) of an individual housing (28) on a portion of the revolution turn, this masked partial zone (16) comprising the center of the individual housing (28).