Chalcogenide Glass Pillar for Infrared Sensors
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Solution Overview
Problem
Small-diameter chalcogenide glasses used in infrared sensors face issues with poor weather resistance and mechanical strength, leading to image distortion and difficulty in size reduction due to polishing flaws and striae.
Innovation Solution
A chalcogenide glass material with an unpolished or fire-polished surface, a pillar shape of 15 mm or less, and a composition of 40 to 90% S+Se+Te, produced through a redraw process at a temperature below the glass transition point, with no striae longer than 500 μm, to enhance weather resistance and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the chalcogenide glass side surface is polished to reduce roughness, then the surface smoothness is improved, but the specific surface area increases and Griffith flaws are produced, causing weather resistance and mechanical strength to deteriorate
Solution Approach 1:
Instead of polishing the side surface to improve smoothness, the patent inverts the approach by deliberately leaving the side surface unpolished or applying a controlled fire-polish that reduces surface area. This resolves the contradiction by achieving adequate surface quality without the harmful effects of traditional polishing, thereby maintaining both smoothness and structural integrity
Solution Approach 2:
The patent changes the surface treatment parameter from mechanical polishing to fire-polishing or leaving unpolished. This parameter change achieves the desired surface smoothness for optical performance while avoiding the creation of Griffith flaws and excessive surface area, thus preserving mechanical strength and weather resistance
2Length of moving object
If the chalcogenide glass diameter is reduced to enable size reduction of infrared sensors, then the sensor size is reduced, but the mechanical strength and weather resistance deteriorate
Solution Approach 1:
The patent changes the surface treatment parameter from mechanical polishing to fire-polishing or leaving unpolished. This parameter change achieves the desired surface smoothness for optical performance while avoiding the creation of Griffith flaws and excessive surface area, thus preserving mechanical strength and weather resistance
3Ease of manufacture
If the chalcogenide glass is produced by conventional methods, then the production process is simple, but striae are produced in the glass material causing image distortion
Solution Approach 1:
The patent changes the production parameter by controlling the drawing temperature to be equal to or lower than the glass transition point plus 100°C. This temperature control parameter change prevents striae formation during the redraw process while maintaining production simplicity, thus achieving both ease of manufacture and high glass homogeneity
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 provides a chalcogenide glass material with improved weather resistance and mechanical strength, reducing image distortion and enabling the production of smaller, more reliable infrared sensors.
Implementation Method 1
chalcogenide glasses are proposed as vitreous materials that can transmit infrared rays with wavelengths of about 8 to 14 μm
Implementation Method 2
Since the side surface is unpolished, the specific surface area is reduced, which makes the weather resistance likely to be increased
Implementation Method 3
A method for producing a chalcogenide glass material according to the present invention includes drawing a glass base material containing, in terms of % by mole, 40 to 90% S+Se+Te by a redraw process
Data Source
AI summary
Provided is a small-diameter chalcogenide glass material having excellent weather resistance and mechanical strength and being suitable as an optical element for an infrared sensor. The chalcogenide glass material has an unpolished side surface, a pillar shape with a diameter of 15 mm or less, and a composition of, in terms of % by mole, 40 to 90% S+Se+Te and an inside of the glass material is free of stria with a length of 500 μm or more.