SPR Oxygen Sensor with Fixed Angle for Low Transmission Rate
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Solution Overview
Problem
Conventional oxygen sensors and oxygen transmission rate (OTR) measurement systems face challenges in accurately measuring low gas transmission rates, particularly in environments like organic light-emitting devices (OLEDs) where sensitivity and specificity are crucial, and existing SPR-based sensors often require complex setups and indirect measurement methods.
Innovation Solution
A surface plasmon resonance (SPR) based oxygen sensor using a transparent substrate coated with metal nanoparticles and an oxygen-sensitive organic material like hemin or hemoglobin, which measures oxygen concentration directly by detecting reflection signals and resonance angle changes, allowing for real-time monitoring and simplified, cost-effective production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional oxygen sensors and OTR measurement systems are used, then measurement capability is provided, but measurement precision and sensitivity are insufficient for very low gas transmission rates
Solution Approach 1:
The patent changes the measurement parameter from indirect tracer gas flow measurement to direct oxygen concentration measurement using SPR. By monitoring resonance angle shifts that directly correlate with oxygen concentration changes, the system achieves higher precision for very low gas transmission rates without relying on differential absorption or tracer gas methods.
Solution Approach 2:
The patent replaces conventional mechanical or chemical measurement systems (IR absorption sensors, tracer gas flow meters) with an optical SPR-based detection system. This substitution enables direct, real-time monitoring of oxygen concentration with superior sensitivity and eliminates the need for complex reference gas comparisons or tracer gas introduction systems.
2Measurement precision
If SPR-based sensors with transparent prisms and metal films are used, then oxygen concentration measurement is enabled, but device complexity increases due to required rotational drivers and multiple components
Solution Approach 1:
The patent extracts and eliminates the rotational driver and angle scanning mechanisms from conventional SPR systems. By using a fixed-angle SPR sensor configuration, the system achieves oxygen concentration measurement without moving parts, significantly reducing device complexity while maintaining measurement capability through direct resonance angle detection at a predetermined angle.
Solution Approach 2:
Instead of scanning through multiple angles to find the resonance point (conventional approach), the patent inverts the approach by fixing the angle and detecting resonance conditions directly. This inversion eliminates the need for rotational mechanisms and angle scanning, simplifying the system architecture while preserving SPR measurement accuracy.
3Measurement precision
If conventional SPR measurement methods with angle scanning are used, then resonance angle measurement is achieved, but measurement time increases
Solution Approach 1:
The patent performs preliminary action by pre-setting the incident light angle to the predetermined angle where SPR resonance occurs. This eliminates the need for real-time angle scanning during measurement, allowing direct detection of resonance conditions and significantly reducing measurement time while maintaining accuracy through the pre-optimized fixed angle configuration.
4Reliability
If highly blockable substrates and sealing materials are used in OLEDs, then protection against water vapor and oxygen is improved, but measurement of very low transmission rates requires higher sensitivity
Solution Approach 1:
The patent replaces indirect measurement methods with direct optical detection using SPR. The fixed-angle SPR sensor provides real-time, high-sensitivity detection of oxygen concentration changes through resonance angle shifts, enabling accurate measurement of extremely low gas transmission rates through OLED encapsulation layers without requiring complex mechanical or chemical measurement systems.
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
Enables direct and sensitive measurement of oxygen concentration, reducing measurement time and system complexity, while being economically viable and suitable for real-time monitoring in various applications, including OLEDs, by using a single wavelength light source and fixed incidence angle.
Implementation Method 1
an oxygen-sensitive organic material (a metal-porphyrin such as hemin or hemoglobin) for adsorbing or desorbing oxygen is applied on a transparent substrate
Implementation Method 2
SPR-based sensors including a transparent prism and a metal film applied to a thickness of about 50 nm thereon and methods of measuring changes in the dielectric constant or refractive index corresponding to changes in a sample on the metal film have been proposed
Data Source
AI summary
Provided is an oxygen sensor using surface plasmon resonance, including: a laser diode emitting light; a polarizer converting the emitted light into polarized light; a prism receiving the polarized light from the polarizer and having a sensor substrate on one surface thereof so that the polarized light is reflected, the sensor substrate coated with oxygen-sensitive organic material; an oxygen concentration measurement chamber provided to enclose the sensor substrate so that oxygen whose concentration is to be measured is contained therein; a photodiode measuring an amount of light reflected from the prism; and a microcontroller unit controlling operation of the oxygen sensor and calculating the oxygen concentration. Further, the oxygen concentration is determined using the microcontroller unit having absolute concentrations corresponding to the amount of light measured using the photodiode, and the oxygen concentration is measured where an incidence angle of the polarized light incident on the sensor substrate is fixed.