Layered Watch Dial for Optical Hand Position Resynchronization

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Solution Overview

Problem

Electromechanical watches with hands are prone to disruptions from shocks and external disturbances, leading to inaccurate time indications, necessitating resynchronization of the hour and minute hands.

Innovation Solution

A watch dial with an autonomous device for determining hand positions, comprising a stack of thin layers with light detection elements, light sources, a photovoltaic module, and a control unit, allowing for constant efficiency and independence from the watch movement's energy source.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the watch uses electromagnetic fields or other external disturbances to drive the hands, then the time indication can be accurate, but the operation of the mechanism is disturbed by shocks and external disturbances leading to false indication

Engineering Contradiction:
Improvetime indication accuracyVSAvoidmechanism operation stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the electromagnetic field-driven mechanical system with an optical detection system. Light sources illuminate the hands, and light detection elements sense the reflected light to determine hand positions. This optical system is not affected by electromagnetic disturbances or shocks, providing reliable and accurate time indication without the vulnerability of electromagnetic mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Extent of automation

If the determination device is integrated into the watch movement, then the timekeeping function is maintained, but the device lacks autonomy and efficiency varies over time

Engineering Contradiction:
Improvedetermination device autonomyVSAvoidenergy efficiency constancy
Core Design Contradiction:
Extent of automationVSUse of energy by moving object

Solution Approach 1:

The patent segments the determination device from the watch movement, integrating it directly into the dial structure. The dial contains light sources, light detection elements, and control circuits as distinct functional modules. This segmentation grants the determination device autonomy, allowing it to operate independently with constant efficiency without being constrained by the watch movement's energy availability.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If the dial structure is simplified without multiple layers, then the manufacturing is easier, but the autonomous determination device cannot be properly integrated

Engineering Contradiction:
Improvedial manufacturing simplicityVSAvoiddial structure complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the determination device components directly into the dial structure. The light sources, light detection elements, and control circuits are integrated within the dial's multi-layer construction, eliminating the need for separate housing or additional structural elements. This merging simplifies manufacturing by combining functions into a single component while managing internal complexity through functional integration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a nested multi-layer dial structure where different functional elements are arranged in concentric or stacked layers. The light sources, detection elements, and control circuits are positioned in specific layers, with each layer serving a particular function. This nesting allows complex functionality to be achieved within a compact, manufacturable structure that maintains ease of production.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Measurement precision

If the light detection elements are positioned to detect hand positions accurately, then the position determination precision is improved, but the device becomes more sensitive to external light conditions

Engineering Contradiction:
Improvehand position determination accuracyVSAvoidexternal light interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent employs periodic action through controlled illumination cycles. The light sources are activated in specific sequences to illuminate different hands or dial regions, and the detection elements are synchronized to detect reflections during these controlled illumination periods. This periodic operation allows the system to distinguish between externally reflected light and internally generated illumination, improving position detection accuracy while filtering out external light interference.

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

The autonomous dial ensures accurate hand position determination and visual messaging, enabling precise timekeeping and resynchronization without affecting the watch movement's autonomy.

Implementation Method 1

a photovoltaic module (5) arranged on a second layer (11) of the stack (9a, 9b)

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

at least one light detection element (23) arranged on a first layer (10) of the stack (9a, 9b)

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4390563A1Device for determining the position of a hand of a watch
Publication Date: 2024.06.26 ETA SA MFG HORLOGERE SUISSE
  • EP4390563A1 patent drawingFigure 1~2
  • EP4390563A1 patent drawingFigure 3~5
  • EP4390563A1 patent drawingFigure 6~7

AI summary

One aspect of the invention relates to a watch dial (2a, 2b) (1) comprising a device (3) for determining the position of at least one hand (24a, 24b) of this watch (1), such a dial (2a, 2b) comprising a visible face (20a) and a hidden face (20b), said dial (2a, 2b) being formed by a stack (9a, 9b) of thin layers (10, 11, 12, 13, 14) of material extending between these two faces (20a, 20b), each of said layers (10, 11, 12, 13, 14) comprising one or more of the functional elements included in said determining device (3): - at least one light detection element (23), - at least one first light source (4a) and at least one second light source (4b), - a self-contained power supply unit (21) comprising a photovoltaic module (5), and - a control unit (7) to manage the operation of each a light source (4a, 4b) and said at least one light detection element (23).