The core parameters of flexible thin film temperature sensors

1、 The core parameters of flexible thin film temperature sensors: understanding is necessary to choose correctly

1.1 Accuracy level: Grade A vs Grade B, the difference is not just the error
According to IEC 60584, the accuracy level of flexible thin film sensors directly affects the reliability of temperature measurement:
A-level (± 0.6 ° C): 0 ° C~100 ° C error ≤± 0.6 ° C, full range (-70 ° C~200 ° C) error ≤± 1.0 ° C, suitable for precision sensitive scenarios such as medical patches and precision instruments;
B-class (± 1.2 ° C): 0 ° C~100 ° C error ≤± 1.2 ° C, full range error ≤± 2.0 ° C, suitable for cost priority scenarios such as consumer electronics (such as headphones, wristbands) and general industrial monitoring.
Key differences: Grade A uses higher purity platinum film (99.99% vs Grade B 99.95%), TCR consistency is controlled at ± 5 ppm/° C (Grade B ± 10 ppm/° C), and long-term drift rate is 30% lower.

1.2 Size and Error: Why is ± 0.01mm an "invisible threshold"? ​

Our sensors are available in two standard sizes: 7x5x0.06mm (universal) and 3x4x0.06mm (miniature), and support ± 0.01mm size customization - this 0.01mm accuracy determines whether it can be embedded in millimeter level space:
3x4mm: Suitable for TWS headphone charging compartment gap, inner side of smartwatch crown;
7x5mm: covering the middle of the smart wristband and and the core area of the medical patch;
Customized size: Previously embedded the sensor into a "contact lens thermometer" (2x3mm) for customers, with an error of still ≤± 0.8 ° C (Class A).

2.1 Medical Health: Choose A-level, accuracy is the "lifeline"
Scenario: Continuous Glucose Monitoring (CGM) Patch, Postoperative Wound Thermostatic Patch;
Recommendation: A-class+3x4mm (miniaturized)+tin plated solder pads (anti-oxidation, suitable for long-term skin adhesion);
Case: A medical technology company used an A-grade 3x4mm sensor to create a "baby fever reducing patch" with a temperature measurement error of ± 0.5 ° C, resulting in a 90% increase in parent satisfaction.
2.2 Consumer Electronics: B-level is sufficient, cost savings of 30%
Scenario: TWS earphone case temperature monitoring, smart wristband motion temperature measurement;
Recommendation: B-class+7x5mm (universal type)+standard solder pads (suitable for batch SMT mounting);
Case: After switching to B-grade 7x5mm, a headphone manufacturer reduced the cost of a single sensor by 0.8 yuan and saved 120000 yuan in annual procurement costs.
2.3 Industrial micro monitoring: customized size+A-level, solving "space anxiety"
Scenario: Robot joint gap temperature measurement, local monitoring of drone battery pack;
Recommendation: A-level+customized size (such as 5x3mm)+tin plated solder pads (anti vibration);
Advantage: The ± 0.01mm size error ensures a "tight fit" and avoids data jumps caused by loose sensors.

3、 Actual test data: What is the difference in accuracy between Class A/Class B? ​

We conducted comparative testing in a 25 ° C constant temperature chamber (with a wire length of 10cm and tin plated solder pad connection):
Temperature point A-level measurement error B-level measurement error conclusion: 0 ° C+0.4 ° C+0.9 ° CA level low temperature segment has significant accuracy advantages of 37 ° C (human body)+0.3 ° C+0.8 ° C Medical scene must choose A-level 100 ° C+0.5 ° C+1.1 ° C Industrial high temperature monitoring A-level is more stable. Conclusion: Selection formula=scene accuracy requirements+spatial limitations
Select A-level: Medical skin patching, precision instruments, low-temperature (-70 ° C~50 ° C) scenarios;
Choose B-level: consumer electronics, general industrial monitoring, cost sensitive scenarios;
Size formula: Choose 3x4mm for micro spaces (<5mm ²), 7x5mm for regular spaces, and customize for special scenarios.
<u> The core value of flexible thin film temperature sensors</u>is to make "temperature measurement" no longer limited by "shape and size" - selecting the right parameters is necessary for the technology to be implemented.

Q: How much is A level more expensive than B level? ​
A: The unit price is 15% to 20% higher, but the long-term reliability return in medical/precision scenarios far exceeds the cost difference.
Q: Can the size error of ± 0.01mm be guaranteed? ​
A: Sure - we use laser cutting+visual inspection, and each sensor comes with a 'size inspection report'.
Q: How many times can tin plated solder pads withstand insertion and extraction? ​
A: ≥ 500 times (industry average of 200 times), suitable for R&D scenarios with frequent debugging.
CTA: Free access to selection reports
Click the consultation button to submit your "scene+accuracy+size" requirements. We will generate a free "Customized Solution for Flexible Thin Film Temperature Sensor" and give away the "SMT Mounting Guide for Micro Sensors"!
References
IEC 60584-1:2013 Thermocouples and Thermistors Standard;
Optimization Report on Temperature Measurement of Infant Fever Reduction Patch by a Medical Technology Company;
Consumer Electronics Association's White Paper on TWS Earphone Temperature Monitoring.

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