Image Sensor Infrared Filter Barrier Layer Against Oxidation
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Solution Overview
Problem
Materials constituting infrared filters in solid-state image sensors, such as infrared cut-off and pass filters, have low light resistance compared to the photoelectric conversion elements, limiting the expansion of the sensors' application range.
Innovation Solution
Incorporating a barrier layer made of silicon oxide between the infrared cut-off filter and the color microlenses to prevent oxidation sources from reaching the infrared cut-off filter, thereby enhancing its light resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an infrared cut-off filter is used in a solid-state image sensor, then the accuracy of visible light detection is improved by preventing infrared light from reaching the photoelectric conversion element, but the light resistance of the sensor deteriorates because the filter materials have low light resistance compared to photoelectric conversion elements
Solution Approach 1:
The patent introduces a barrier layer as an intermediary component between the infrared cut-off filter and the external environment. This barrier layer specifically blocks oxidation sources while allowing light to pass through, thereby protecting the filter materials from oxidation without interfering with the optical functionality. The barrier layer acts as a mediator that separates the filter from harmful environmental factors, resolving the contradiction between maintaining detection accuracy and improving light resistance.
Solution Approach 2:
The patent creates a protected environment for the infrared cut-off filter by introducing a barrier layer that excludes oxidation sources. This effectively creates an inert atmosphere around the filter materials, preventing oxidative degradation while allowing the filter to maintain its optical properties. The barrier layer establishes a chemically stable environment that preserves both the light resistance and the detection accuracy of the sensor.
2Adaptability or versatility
If the application range of solid-state image sensors is expanded through improved image processing and sensing, then the versatility of the sensors is improved, but the demand for higher light resistance increases because existing filter materials have insufficient light resistance
Solution Approach 1:
The barrier layer serves as a protective intermediary that enables the use of various filter materials with different optical properties while maintaining high light resistance. This allows the sensor to be adapted for different applications (expanded versatility) without being constrained by the light resistance limitations of the filter materials themselves. The barrier layer decouples the optical performance requirements from the light resistance requirements.
3Device complexity
If oxidation sources are allowed to reach the infrared cut-off filter, then the structure remains simple, but oxidation of the filter occurs leading to reduced light resistance
Solution Approach 1:
The patent divides the sensor structure into distinct functional layers: the infrared cut-off filter layer and the barrier layer. This segmentation allows each layer to perform its specific function - the filter for optical wavelength selection and the barrier for chemical protection. The segmented structure maintains relative simplicity while effectively addressing the oxidation problem through functional specialization.
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 barrier layer effectively suppresses oxidation of the infrared cut-off filter, improving the light resistance of the solid-state image sensor and maintaining the accuracy of visible and infrared light detection.
Implementation Method 1
an oxidation source is prevented from reaching the infrared cut-off filter, oxidation of the infrared cut-off filter by the oxidation source is suppressed
Data Source
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AI summary
A solid-state image sensor filter includes: a light-incident surface on which light is incident; an infrared filter located on a side of a photoelectric conversion element on which the light-incident surface is disposed; and a barrier layer located on a side of the infrared filter on which the light-incident surface is disposed, the barrier layer being provided to suppress transmission of an oxidation source to thereby prevent the infrared filter from being oxidized.