Laser-Grooved Timepiece Dial for Stereoscopic Hour Indicators

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Solution Overview

Problem

Existing decorating methods for timepiece dials, such as those described in JP 2022-11407 A, fail to provide a sufficient stereoscopic effect for hour indicators while maintaining a thin profile, and embedding abbreviated characters complicates the design.

Innovation Solution

A decorating method using laser processing to create a recessed portion with intersecting grooves and protruding portions on the dial, forming a stereoscopic hour indicator by digging down the decorative portion from the front surface, allowing for high contrast and reduced thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the hour indicator is decorated to be flush with the front surface of the dial, then the manufacturing process is simple, but the stereoscopic effect is poor

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidstereoscopic effect
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The patent applies laser processing to create grooves that extend in the thickness direction (Z-axis) of the dial, transforming a two-dimensional flat decoration into a three-dimensional structure with depth. This dimensional change provides the stereoscopic effect by creating visible depth and layering, while still using a relatively simple laser-based manufacturing process rather than complex mechanical machining or multiple assembly steps.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Shape

If abbreviated characters are embedded at the dial to obtain a stereoscopic effect, then the stereoscopic effect is improved, but the thickness cannot be reduced

Engineering Contradiction:
Improvestereoscopic effectVSAvoidthickness
Core Design Contradiction:
ShapeVSLength of stationary object

Solution Approach 1:

Instead of embedding three-dimensional characters throughout the entire dial thickness, the patent applies laser grooving locally only to the hour indicator area. The grooves are concentrated in specific regions where depth is needed for the stereoscopic effect, while the rest of the dial maintains its thin profile. This localized approach provides the desired three-dimensional appearance without increasing the overall thickness of the timepiece.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent creates the stereoscopic effect by utilizing the thickness dimension through laser grooves rather than embedding characters that would require additional material layers. By processing grooves in the Z-axis direction within the existing thickness, the design achieves three-dimensionality without adding significant thickness, allowing the hands to be positioned directly above the dial surface.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Illumination intensity

If the groove depth is increased to improve lightness contrast, then the lightness expression is enhanced, but the stereoscopic effect becomes less pronounced

Engineering Contradiction:
Improvelightness contrastVSAvoidstereoscopic effect
Core Design Contradiction:
Illumination intensityVSShape

Solution Approach 1:

The patent creates different groove depths at different locations within the hour indicator. Areas requiring high lightness contrast have deeper grooves, while areas where the stereoscopic effect is most important have shallower grooves. This localized variation in groove depth allows simultaneous optimization of both lightness expression and three-dimensional appearance, as each region's groove depth is tailored to its specific functional requirement.

Inventive Principle:
Principle #3Local quality

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 method achieves a clear, stereoscopic hour indicator with high contrast and reduced thickness, enabling a thinner timepiece design without the need for embedded characters, and allows for adjustable lightness and design variations through groove depth control.

Implementation Method 1

A decorating method of a dial 5, which exerts a stereoscopic effect, is provided. More specifically, a decorative portion 17 having a stereoscopic effect is provided at a bottom surface 12a of a recessed portion 12 dug down by one step from a front surface 5b of the dial 5.

Methodology Applied
Scientific EffectLaser processing: Laser

Implementation Method 2

there has been known a technique of decorating a timepiece component such as a dial by laser processing

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP4300215B1Decorating method of dial, dial, and timepiece
Publication Date: 2026.02.11 SEIKO EPSON CORP
  • EP4300215B1 patent drawingFigure 1
  • EP4300215B1 patent drawingFigure 2
  • EP4300215B1 patent drawingFigure 3

AI summary

A dial includes a recessed portion formed by laser irradiation, and a decorative portion formed at a bottom surface of the recessed portion by laser irradiation, including a first groove extending in a first direction, and a second groove extending in a second direction intersecting the first direction, and including a plurality of protruding portions provided in a region partitioned by a plurality of the first grooves, and a plurality of the second grooves.