Capacitor Auxiliary Drive for Electronic Timepiece Startup

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Solution Overview

Problem

Electronic timepieces with electricity generation functions experience prolonged startup times when secondary battery voltage recovery is slow, leading to stopped operations and potential loss of hand position data upon restart.

Innovation Solution

Incorporating a secondary capacitor module and a switching control system that manages power supply connections between a solar cell, secondary battery, and load circuit, allowing for rapid charging of the capacitor and auxiliary driving of hands to quickly start the timepiece and prevent hand position loss during voltage recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If a secondary battery is used to store generated electricity, then the timepiece can operate even when electricity is not being generated, but the startup time is prolonged when the secondary battery voltage recovers slowly

Engineering Contradiction:
Improveoperation durationVSAvoidstartup time
Core Design Contradiction:
Duration of action of stationary objectVSLoss of time

Solution Approach 1:

The power storage system is segmented into two distinct components: a secondary battery for long-term energy storage and a capacitor for rapid energy delivery during startup. This segmentation allows each component to fulfill its optimal function - the battery provides sustained operation while the capacitor enables quick voltage recovery and rapid startup when needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The capacitor acts as an intermediary between the secondary battery and the load circuit. When the timepiece needs to start up quickly, the capacitor receives charge from the battery and delivers it rapidly to the load, mediating the energy transfer and enabling fast startup without being limited by the battery's slower voltage recovery characteristics.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If the hands are stopped before exhaustion of the secondary battery, then the position of the hands is preserved, but the user may lose track of time and the timepiece remains stopped

Engineering Contradiction:
Improvehand position informationVSAvoidtime display functionality
Core Design Contradiction:
Loss of informationVSProductivity

Solution Approach 1:

The system performs preliminary charging of the capacitor before the secondary battery is fully exhausted. This preliminary action ensures that when the timepiece needs to restart, the capacitor is already charged and ready to provide immediate power, enabling the hands to start moving quickly rather than remaining stopped for an extended period.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control circuit continuously monitors the voltage of the secondary battery and the charge state of the capacitor, using this feedback information to determine the optimal timing for switching between power sources and to activate the hands at the appropriate moment, ensuring both information preservation and functional continuity.

Inventive Principle:
Principle #23Feedback

3Loss of time

If a capacitor is added to quickly start the timepiece, then the startup time is reduced, but the device complexity increases

Engineering Contradiction:
Improvestartup timeVSAvoidpower supply system complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent merges the secondary battery and capacitor into a unified power supply system with integrated control logic. The control circuit automatically manages the interaction between the two energy storage devices, selecting and switching between them based on real-time voltage and charge state monitoring, thereby simplifying the overall system operation despite the added component.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If the hands are quickly started after electricity generation restarts, then the user is notified of normal operation, but hand position loss may occur if electricity generation stops immediately after restart

Engineering Contradiction:
Improveuser notification of operation stateVSAvoidhand position data
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The system provides beforehand cushioning by maintaining a charged capacitor as a buffer energy source. When electricity generation restarts, the pre-charged capacitor ensures the hands can be quickly activated and stabilized. This cushioning effect prevents hand position loss by ensuring continuous power availability even if generation stops immediately after restart, giving the system time to stabilize the hand positions.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 rapid startup of the timepiece and maintains accurate hand positions by using the capacitor for auxiliary driving when electricity generation resumes, ensuring the user is notified of the timepiece's operational state and preventing hand position loss.

Implementation Method 1

a solar power generation module that generates electricity by receiving light through a solar cell (12)

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

a capacitor (3) as a second capacitor module, which store generated electricity

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

a diode D1 which rectifies a current generated by the solar cell 12

Methodology Applied
Scientific EffectRectification: Diode

Data Source

PatentEP2202591B1Electronic timepiece
Publication Date: 2017.06.21 CASIO COMPUTER CO LTD
  • EP2202591B1 patent drawingFigure 1
  • EP2202591B1 patent drawingFigure 2
  • EP2202591B1 patent drawingFigure 3A~3C

AI summary

An electronic timepiece comprises a drive module (24, 14) configured to drive a hand, an electricity generation module (12), first and second capacitor modules (2, 3), the second capacitor module (3) having smaller capacitance than the first capacitor module (2), and an auxiliary drive control module (21) which causes the drive module (24, 14) to perform the auxiliary driving when the charge level of the second capacitor module (3) exceeds a third level (Vth1) indicating an amount of electricity which enables the auxiliary driving, and waits until the charge level of the second capacitor module (3) exceeds the third level (Vth1) after performing the auxiliary driving.