Humidity Sensor Common Power Line Temperature Correction
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Solution Overview
Problem
Existing humidity detection systems for image forming apparatuses are costly due to the need for a sensor module with a controller that varies with temperature changes, leading to increased costs for both the sensor module and the physical quantity changing device.
Innovation Solution
A humidity detecting device with a detection unit comprising a humidity sensor and a temperature sensor connected by a common power supply, along with a controller that includes an application circuit for power supply voltage application, a read circuit for signal processing, and a correction circuit using a temperature correction table to improve accuracy and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor module with controller is used to detect humidity while compensating for temperature changes, then measurement precision is improved, but device cost increases
Solution Approach 1:
The patent divides the detection unit into separate sensor elements (humidity sensor and temperature sensor) rather than using an integrated sensor module. This segmentation allows for lower-cost individual components while maintaining the ability to compensate for temperature effects through software correction using a correction table stored in the controller.
Solution Approach 2:
The patent introduces a temperature sensor as an intermediary to measure temperature separately, which then serves as input data for the correction circuit. This separate temperature measurement allows the system to compensate for temperature-induced humidity sensor drift without requiring an expensive integrated sensor module with built-in temperature compensation.
2Measurement precision
If separate signal lines are used for humidity sensor and temperature sensor, then measurement precision is improved, but wiring cost increases
Solution Approach 1:
The patent merges the power supply lines for the humidity sensor and temperature sensor into a single common power supply line. Both sensors share the same power supply circuitry, which reduces the number of wiring connections required while maintaining independent signal processing for each sensor through the controller's read circuits.
3Reliability
If multiple power supply lines are used for different sensors, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent designs the common power supply line to serve multiple functions by powering both the humidity sensor and temperature sensor through the same line. This universal power supply approach reduces circuit complexity while maintaining reliable operation, as the single power supply line can accommodate the power requirements of both sensor elements without requiring separate dedicated power circuits.
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 reduces the cost and improves the accuracy of humidity detection by sharing a power supply line between sensors, absorbing power supply variations, and correcting humidity readings based on temperature, thus providing reliable humidity detection independent of environmental temperature.
Implementation Method 1
a humidity sensor for producing a humidity detection signal by detecting the humidity
Implementation Method 2
a temperature sensor for producing a temperature detection signal by detecting a temperature surrounding the humidity sensor
Data Source
AI summary
The humidity detecting device includes a detection unit and a controller. The detection unit includes a humidity sensor for producing a humidity detection signal by detecting a humidity, a temperature sensor for producing a temperature detection signal by detecting a temperature surrounding the humidity sensor, and a common power supply line connected to the humidity sensor and the temperature sensor. The controller includes an application circuit for applying a power supply voltage to the humidity sensor and the temperature sensor through the common power supply line, a read circuit for producing a read-out humidity value corresponding to the humidity detection signal and a read-out temperature value corresponding to the temperature detection signal, and a correction circuit for correcting the read-out humidity value based on the read-out temperature value.