Sapphire Glass / Lens Thickness Measurement

Sapphire glass (also known as synthetic sapphire) is a high-performance material used in precision optical applications. Unlike natural sapphire gemstones, synthetic sapphire is widely used in watch glass, optical windows, and infrared applications.

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Why Sapphire Glass?

Sapphire and ruby glass have unique material advantages:

  • Excellent heat resistance

  • High hardness (resistant to scratches)

  • Infrared transparency

  • Strong chemical and electrical stability

Because of these features, sapphire glass is used in:

  • Watch lenses

  • Infrared/thermal imaging devices (e.g. night vision cameras)

  • Military and aerospace optics

  • High-power laser windows, prisms, and lenses

  • Observation windows in cryogenic experiments

Measurement Challenges

In production, measuring the thickness and curvature of sapphire lenses is critical.

Common Issues:

    1. Curved surfaces – Need to evaluate if the curvature is within tolerance.

    2. Thickness range – Varies from 5 µm to 3400 µm, especially important at the center point of the lens.

    3. Delicate material – Contact measurement methods may damage the surface or leave contamination.

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The Solution: Non-contact Measurement with Hypersen Chromatic Confocal Sensors

Hypersen’s chromatic confocal sensors offer a high-precision, non-contact method for inspecting sapphire glass.

Key Benefits:

  • High accuracy – Can precisely detect the center thickness

  • Non-contact measurement – No damage or contamination risk

  • High speed – Sampling rate up to 7200 Hz

  • Real-time display – Measurement results shown instantly

  • Flexible integration – I/O output for in-line quality control

Real Application Example

A watch lens manufacturer uses the Hypersen sensor to:

  • Measure the center thickness of domed sapphire lenses

  • Evaluate the curvature to ensure correct shape

  • Perform automated in-line inspection for real-time pass/fail judgment