Bolometer Detector Pixel Thermal Isolation via Layer Segmentation
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Solution Overview
Problem
Bolometer-type detectors face challenges with heat inflow between pixels, leading to unclear images due to thermal conductivity issues, particularly with parylene-based heat insulating layers and metal wiring, which complicates the manufacturing process and increases costs.
Innovation Solution
A bolometer-type detector design where the heat insulating layer is partially removed between adjacent pixels, and the wiring for signal output is disposed in a layer different from the bolometer films, reducing inter-pixel heat transfer by at least 50% in length and 100 nm or wider in width, allowing for improved thermal isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a parylene-based heat insulating layer is used between bolometer films, then thermal insulation in the stacking direction is improved, but heat flow between adjacent pixels increases due to low thermal insulation in the horizontal direction
Solution Approach 1:
The heat insulating layer is segmented into pixel-specific regions, with the layer being removed in the horizontal direction between adjacent pixels while maintaining continuity in the stacking direction. This segmentation allows the structure to provide thermal insulation where needed (vertically) while allowing heat dissipation where needed (horizontally between pixels).
Solution Approach 2:
The heat insulating layer is designed with different properties in different regions: it maintains thermal insulation properties in the stacking direction (vertical) while being removed or modified in the horizontal direction between pixels. This creates local quality differences that simultaneously achieve vertical insulation and horizontal heat dissipation.
2Reliability
If metal wiring is disposed between bolometer films for signal output, then electrical connection is improved, but inter-pixel heat flow increases due to high thermal conductivity of metal
Solution Approach 1:
The metal wiring is repositioned from a planar arrangement between bolometer films to a three-dimensional arrangement in a different layer. Specifically, the wiring is disposed in a layer above or below the bolometer film layer, separated by heat insulating layers. This dimensional change allows electrical connection while preventing direct thermal coupling between adjacent pixels.
3Temperature
If a diaphragm-type heat-insulating unit is used to separate the bolometer from the substrate, then thermal isolation is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The complex diaphragm-type heat-insulating unit is replaced by extracting and removing the heat insulating layer in specific regions between pixels. Instead of using a complex three-dimensional diaphragm structure, the patent uses a simpler approach of removing the heat insulating layer material where it is not needed, thereby simplifying the manufacturing process while maintaining thermal isolation.
4Object-affected harmful factors
If the heat insulating layer is completely removed between pixels, then heat flow between pixels is reduced, but thermal insulation between bolometer and substrate is compromised
Solution Approach 1:
The heat insulating layer is selectively removed with different local qualities: it is removed in the horizontal direction between pixels to reduce heat flow, while it is maintained in the stacking direction to preserve thermal insulation between the bolometer and substrate. This local quality differentiation resolves the contradiction between the two opposing requirements.
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
This design effectively reduces heat inflow between pixels, enhancing image clarity and simplifying the manufacturing process by eliminating the need for complex vacuum packaging and increasing the fill factor of the detector.
Implementation Method 1
a heat insulating layer provided on a substrate, between a bolometer part and the substrate in place of the gap described above to prevent heat conduction from the bolometer part to the substrate
Implementation Method 2
When irradiated with infrared rays, the infrared detection part is heated and detects the resistance change caused by temperature change
Implementation Method 3
a bolometer-type uncooled infrared sensors using a titanium film or vanadium oxide as a resistor material
Data Source
AI summary
An example object of the present invention is to provide a bolometer-type detector capable of reducing heat transfer between pixels. A bolometer-type detector according to an example aspect of the present invention includes a plurality of pixels, and at least includes: a substrate, a heat insulating layer provided on the substrate, bolometer films provided on individual pixels on the heat insulating layer, and a wiring for signal output connected to contact electrodes provided in contact with the bolometer films, wherein the wiring for signal output is disposed in a layer different from the bolometer films, and the heat insulating layer between adjacent pixels is removed at least partially in the depth direction and in a region of a length of 50% or longer and a width of 100 nm or wider of a closed curve that surrounds each bolometer film.