Solar Timepiece Charging Notification via Illuminance Analysis
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Solution Overview
Problem
Existing electronic timepieces face challenges in accurately notifying users when the secondary battery needs charging, as the battery voltage does not have a proportional relationship with stored energy, leading to inefficient power consumption and potential suspension of functions due to delayed charging notifications.
Innovation Solution
The electronic timepiece employs a CPU-controlled charging management process that intermittently measures generated power, converts it into points based on illuminance, and sets threshold values for charging urging notifications, allowing timely alerts without excessive energy consumption by recognizing the depth of discharge through voltage thresholds and illuminance analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the generated power is measured continuously to notify the user timely that the secondary battery needs charging, then the notification timing is improved, but the energy consumption increases due to power consumption in the detection resistor
Solution Approach 1:
The patent implements periodic measurement of generated power instead of continuous measurement. The control unit measures the generated power at predetermined intervals, which reduces the energy consumption of the detection resistor while still providing timely notification to the user about battery charging needs. This periodic action maintains the reliability of notification timing while significantly lowering the overall energy consumption of the power measurement system.
2Device complexity
If the battery voltage is used to detect battery capacity, then the detection is simple, but the accuracy deteriorates when the battery capacity is in the medium range where voltage remains constant
Solution Approach 1:
The patent introduces an illuminance sensor as an intermediary element to estimate the generated power, which then serves as a basis for determining battery capacity. Instead of directly measuring battery voltage to determine capacity, the system uses the illuminance sensor to measure light conditions, calculates the expected generated power, and compares this with the actual battery state. This intermediary approach provides more accurate battery capacity estimation in the medium range where voltage remains constant, while maintaining relative simplicity through the use of existing sensor data.
3Loss of energy
If the detection resistor has small resistance to minimize power consumption, then the energy loss is reduced, but the measurement precision deteriorates because the generated current is not very large
Solution Approach 1:
The patent changes the measurement parameters by measuring voltage across the detection resistor at predetermined intervals rather than continuously, and by using the illuminance sensor data to complement the electrical measurements. The control unit calculates generated power based on both the voltage measurement and illuminance conditions, which allows for accurate power measurement while using a detection resistor with resistance optimized for low power consumption. This parameter change approach enables the system to maintain measurement precision through intelligent calculation rather than relying solely on high-resistance components.
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
This approach enables timely user notification to start power generation, maintaining proper charging states without suspending functions, while minimizing energy consumption by intermittent power measurements and adjusting threshold values to account for varying illuminance conditions.
Implementation Method 1
electronic timepiece which is equipped with a solar panel and a secondary battery and operates on electric energy that is generated by the solar panel
Data Source
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AI summary
An electronic timepiece includes: a power generation unit (20) that generates power by taking in energy from outside; a battery (21) that stores the generated power; a generated power monitor (22,10) that intermittently and repeatedly measures the power generated by the power generation unit; an input amount analyzing section (10) that performs an analysis on an energy input amount based on the measurement results of the generated power monitor; and a power generation urging notification controller (10) that starts power generation urging notification if it is determined, based on the analysis result of the input amount analyzing section, that the energy input amount is low on average.