Moon Phase Display Mechanism With Curved Shutter for Thin Watches

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Solution Overview

Problem

Existing moon phase display mechanisms in timepieces, particularly wristwatches, are either decorative and aesthetically distant from the actual lunar appearance or bulky, making them difficult to integrate into a clockwork movement.

Innovation Solution

A moon phase display mechanism using a plano-concave lens and a curved shutter to represent the lunar phases, providing a realistic and compact representation that is easily understandable, powered by a clockwork movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a rotating sphere is used to represent the Moon's phases, then the representation is realistic and faithful to the actual appearance, but the mechanism becomes thick and takes up considerable space

Engineering Contradiction:
Improveaccuracy of moon phase representationVSAvoidthickness of the mechanism
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent uses a two-dimensional printed representation of the Moon's phases on a dial plate instead of a three-dimensional rotating sphere. This copy approach maintains the visual accuracy of moon phases while dramatically reducing the mechanical complexity and thickness required, allowing integration into thin wristwatch movements.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical rotating sphere system with an optical-mechanical system using a fixed dial plate and a movable shutter. The shutter, controlled by a cam mechanism, opens and closes to reveal different phases of the Moon printed on the dial plate, eliminating the need for a thick rotating sphere while maintaining realistic representation.

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

2Measurement precision

If a rotating sphere is used to represent the Moon's phases, then the representation is realistic, but it is difficult to integrate into a clockwork movement, especially in a wristwatch

Engineering Contradiction:
Improveaccuracy of moon phase representationVSAvoidintegration difficulty into clockwork movement
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

By using a printed two-dimensional representation of the Moon's phases on a flat dial plate, the patent eliminates the complex mechanical structure of a rotating sphere. This copying approach simplifies the mechanism to a程度 that it can be easily integrated into thin wristwatch movements without requiring large空间的 spherical components.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent substitutes the complex rotating sphere mechanism with a simpler system comprising a fixed dial plate with printed phases and a movable shutter controlled by a cam and lever mechanism. This substitution dramatically reduces the mechanical complexity and spatial requirements, enabling integration into standard wristwatch calibers.

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

3Length of stationary object

If simple pointers or disc representations are used, then the mechanism is thin and easy to integrate, but the representation is decorative and bears only a distant relation to how the lunar orb appears in the sky

Engineering Contradiction:
Improvethickness of the mechanismVSAvoidaccuracy of moon phase representation
Core Design Contradiction:
Length of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies different visual qualities to different parts of the dial plate, with each section showing an accurate representation of the Moon's phase at that point in the lunar cycle. The shutter selectively reveals these locally accurate representations, maintaining both thinness and photorealistic accuracy simultaneously.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces dynamic control through the movable shutter that opens and closes to reveal different phases. This dynamic element transforms the static printed representations into an animated sequence that accurately depicts the Moon's phases over time, maintaining photorealistic accuracy while keeping the mechanism thin.

Inventive Principle:
Principle #15Dynamics

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 mechanism offers a realistic and compact display of lunar phases, allowing easy integration into a wristwatch while ensuring the phases are always visible and easily discernible, enhancing user understanding.

Implementation Method 1

the transparent support is in the form of a plano-concave lens delimited at the top, on the observer's side, by a flat surface which receives the representation of the Moon, and delimited at the bottom by a concave surface which is given a profile preferably but not necessarily aspherical

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3842875B1Mechanism for displaying the phases of the moon
Publication Date: 2026.01.28 BLANCPAIN SA
  • EP3842875B1 patent drawingFigure 1
  • EP3842875B1 patent drawingFigure 2
  • EP3842875B1 patent drawingFigure 3A~3B

AI summary

The invention relates to a moon phase display mechanism powered by a clockwork movement, this moon phase display mechanism (1) comprising a transparent support (98) having an upper face (100) and a lower face (102) extending at a distance from the upper face (100), a representation (104) of the Moon being projected onto one of the upper (100) or lower (102) faces of this transparent support (98), a substrate (106) being disposed under the transparent support (98), at a distance from its lower face (102), the moon phase display mechanism (1) also comprising a shutter (94) which is driven by drive means (72) powered by the clockwork movement and which is arranged to move between the transparent support (98) and the substrate (106), the shutter (94) and the substrate (106) having display contrasts reversed relative to each other,the shutter (94) being moved from an initial position to a final position during a lunar cycle, so as to reveal day after day to an observer the appearance of the Moon as it passes from the new moon to the first quarter moon, then from the first quarter moon to the full moon, then to the last quarter moon and finally to the new moon, the shutter (94) being returned by the drive means from its final position to its initial position at the end of the lunar cycle.