Through Hole Detection in Electronic Timepieces

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Solution Overview

Problem

Existing through hole detection systems in electronic timepieces are prone to errors due to external light interference and require prolonged AD conversion processes, leading to reduced detection accuracy and increased power consumption.

Innovation Solution

A through hole formation state determining device that captures a detected signal from a photodetection element when the light emission element is in a non-emission state to set the external light intensity, and then offsets this intensity to compare with the signal when the light emission element is active, allowing for accurate detection of aperture alignment without external light influence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If external light intensity is not compensated, then the photodetection element can continuously detect light signals, but detection accuracy deteriorates due to external light interference

Engineering Contradiction:

Improvedetection accuracyVSAvoidexternal light interference

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary measurement of external light intensity by capturing the photodetection element's output when the light emission element is non-emission, before conducting the actual through-hole detection. This preliminary action allows the system to compensate for external light interference by subtracting the measured external light intensity from the total detected signal, thereby maintaining detection accuracy despite the presence of external light.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If AD conversion is performed multiple times to ensure detection accuracy, then measurement reliability improves, but detection time increases

Engineering Contradiction:

Improvedetection reliabilityVSAvoiddetection time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs external light intensity measurement in advance before the actual through-hole detection, so that when the light emission element is activated, the external light component is already known and can be immediately subtracted from the photodetection element's output. This eliminates the need for repeated AD conversion cycles, reducing detection time while maintaining reliability through a single compensated measurement.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses the measured external light intensity as feedback to correct the detection signal. By subtracting the external light intensity from the total light detected by the photodetection element, the system obtains an accurate signal representing only the light from the light emission element passing through the apertures, ensuring reliable detection without repeated measurements.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If the light emission element emits light continuously for AD conversion, then detection accuracy improves, but power consumption increases

Engineering Contradiction:

Improvedetection accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

Instead of continuous emission, the light emission element is activated only in periodic intervals - first to measure external light intensity (with the element non-emission), then briefly to perform the actual through-hole detection. This periodic action significantly reduces power consumption compared to continuous emission, while detection accuracy is maintained through the compensated measurement method that uses the brief emission periods to obtain accurate signals.

Inventive Principle:

Principle #19Periodic action

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 solution enhances detection accuracy and reduces power consumption by minimizing the time required for AD conversion and emission, enabling faster and more precise alignment of hands in analog display timepieces.

Implementation Method 1

a photodetection element which detects light from the light emission element, thereby outputting a detected signal indicative of the intensity of the detected light

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentUS7633075B2Through hole formation state detecting device and electronic timepiece using the detecting device

Publication Date: 2009.12.15 CASIO COMPUTER CO LTD

AI summary

When a light emission element emits no light, a detected signal from a photodetection element is captured as an intensity of external light. Then, a threshold value is offset by the intensity of the external light. The offset threshold is then compared to a detected signal from the photodetection element when the light emission element emits light, thereby determining the presence of a through hole between the light emission element and the photodetection element through which hole light passes without being influenced by external light.