Infrared Sensor Bandpass Filter Merged Gate Electrode
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Solution Overview
Problem
Infrared ray sensing thin film transistors in liquid crystal displays malfunction due to reaction with visible rays, and existing manufacturing processes are complex and costly.
Innovation Solution
A bandpass filter is integrated with the optical sensor to block visible rays by using a metal pattern or particles with specific spacings and shapes, allowing only infrared light to pass, and the filter is formed on the same surface as the gate electrode with the same material to simplify manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bandpass filter is added to block visible rays from reaching the infrared ray sensing thin film transistor, then the reliability of the optical sensor is improved, but the device complexity increases
Solution Approach 1:
The bandpass filter is merged with the gate electrode of the infrared ray sensing thin film transistor, forming a single integrated structure. The gate electrode serves dual functions: as the control electrode for the transistor and as the bandpass filter that blocks visible rays. This merging eliminates the need for a separate filter component while maintaining the reliability improvement.
Solution Approach 2:
The gate electrode is designed to perform multiple functions simultaneously: electrical control of the transistor channel and optical filtering of visible rays. By making the gate electrode universal, the patent avoids adding extra components and reduces the overall device complexity while still preventing visible ray interference.
2Manufacturing precision
If separate manufacturing processes are used for the filter and gate electrode, then the filtering precision is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The manufacturing process merges the formation of the bandpass filter and gate electrode into a single step. The gate electrode material is deposited and patterned to simultaneously create both the electrical gate structure and the optical filter pattern, eliminating the need for separate manufacturing processes while maintaining filtering precision.
Solution Approach 2:
The gate electrode is designed to serve dual purposes, allowing a single manufacturing process to produce both the electrical control element and the optical filter. This universal approach simplifies manufacturing while ensuring that the filtering precision requirements are met through proper material selection and pattern design.
3Reliability
If different materials are used for the filter and gate electrode, then the filtering performance is improved, but the manufacturing cost increases
Solution Approach 1:
The gate electrode material is selected to perform both electrical conduction and optical filtering functions. Materials such as aluminum, molybdenum, copper, gold, silver, or chromium are used, which provide both good electrical properties and appropriate optical characteristics for blocking visible rays while transmitting infrared wavelengths.
Solution Approach 2:
The optical properties of the gate electrode material are optimized by adjusting parameters such as layer thickness and pattern geometry. By controlling these parameters, the single material can achieve the desired filtering performance for visible rays while maintaining its electrical functionality as a gate electrode, eliminating the need for multiple materials.
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 prevents visible ray interference, ensuring accurate filtering and reducing manufacturing costs by simplifying the process and using shared materials for the filter and gate electrode.
Implementation Method 1
a bandpass filter formed on the substrate and sized and arranged to pass the infrared light
Implementation Method 2
The bandpass filter may comprise a metal material patterned to have features, successive features spaced apart from each other by a predetermined period so as to pass the infrared light and to block the visible light
Data Source
AI summary
An exemplary embodiment of the present invention provides an optical sensor, including: a substrate; an infrared ray sensing thin film transistor including a first semiconductor layer that is formed on the substrate and arranged to operate by receiving infrared light, and a bandpass filter formed on the substrate and sized and arranged to pass the infrared light; a visible ray sensing thin film transistor including a second semiconductor layer formed on the substrate and arranged to operate by receiving visible light; and a switching thin film transistor including a third semiconductor layer formed on the substrate, wherein the bandpass filter may be formed of a metal material patterned to have features, successive features spaced apart from each other by a predetermined period so as to pass the infrared light and to block the visible light.