Reinforced Watch Case with Sapphire Crystal Orientation
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Solution Overview
Problem
Existing wristwatch cases designed for great depths require significant thickness, which limits their ability to reach even greater depths and is not compatible with a wristwatch design.
Innovation Solution
A wristwatch case featuring a sapphire crystal with a 'type C' crystallographic orientation, where the optical axis is perpendicular to the crystal plane, and a load-reacting surface area ratio (A2a/A1a) of 0.2 or greater, allowing for a reduced thickness while maintaining high mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the watch case thickness is increased to withstand high pressure at great depths, then the pressure resistance is improved, but the watch case thickness reaches the maximum possible limit for wristwatch applications
Solution Approach 1:
The patent changes the crystallographic orientation parameter of the sapphire crystal from conventional orientations to a specific orientation where the optical axis is perpendicular to the crystal plane. This parameter change results in superior mechanical strength and pressure resistance, allowing the crystal to withstand extreme depths while maintaining a reduced thickness suitable for wristwatch applications.
Solution Approach 2:
The patent employs a composite structure combining sapphire crystal with specific crystallographic orientation and a load-reacting ring. The load-reacting ring works in conjunction with the sapphire crystal to distribute and bear the pressure load, creating a composite system that achieves enhanced pressure resistance without requiring excessive thickness.
2Strength
If the load-reacting surface area ratio (A2a/A1a) is increased to improve pressure distribution, then the mechanical strength is improved, but the crystal surface area available for other functions is reduced
Solution Approach 1:
The patent optimizes the geometric parameter of the load-reacting surface area ratio (A2a/A1a) to a specific range. This parameter optimization ensures adequate pressure distribution and mechanical strength while minimizing the impact on the overall crystal surface area, balancing structural requirements with functional requirements.
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 solution enables a wristwatch case to withstand extremely high pressures, allowing it to reach depths of up to 11,000 meters with a reduced thickness, while maintaining the necessary mechanical strength and watertightness.
Implementation Method 1
a sapphire obtained by the Kyropoulos technique or by an EFG method of crystal growth
Data Source
AI summary
The wristwatch includes a case middle (3) and a load-reacting surface (2a) which is a surface of a load-reacting ring (2) distinct from the case middle (3), and a protective casing including the crystal (1), the case middle (3), and the load-reacting ring (2) housed within the case middle (3) including the load-reacting surface (2a) against which the crystal (1) bears, and a back (4) bearing against the load-reacting ring (2).