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Suzhou Xishi Technology Co., Ltd
Why choose a cost-effective white light interference film thickness gauge to assist in the testing of the hardened film thickness of eyeglass lenses?
Date: 2025-11-14Read: 3
High cost optical interference film thickness gauge is increasingly becoming a better choice for high-precision and non-contact detection in the testing of hardened film thickness of eyeglass lenses. With its excellent measurement accuracy and strong analytical ability for transparent/semi transparent films, it provides reliable quality assurance and technical support for the eyewear manufacturing industry.
1、 Why choose an optical interference film thickness gauge?
1. Non contact and non-destructive measurement
-Not damaging the surface of the lens, especially suitable for finished lenses that have already been coated with multiple layers of film (such as hardening film+anti reflection film+anti fouling film);
-No coupling agent or physical contact is required to avoid contamination or scratches.
2. High precision and high resolution
-The measurement accuracy can reach the nanometer level (± 1 nm or higher);
-Can clearly distinguish the thickness of the hardened film within the range of 2-10 μ m, and even identify sub micron level changes in the film layer.
3. Suitable for transparent media
-The hardened film is usually made of transparent materials such as silicon dioxide (SiO?) and organosilane, and the substrate is resin (CR-39, PC, MR series, etc.);
-Optical interferometry is based on the reflection interference signal of light at the upper and lower interfaces of the film layer, which is naturally suitable for such structures.
4. Realize surface distribution analysis
-Some devices support mapping function, which can generate a two-dimensional distribution map of the hardened film thickness on the entire lens to evaluate uniformity;
-Curved lenses, such as progressive multifocal lenses, can also be compensated for curvature effects through software.
2、 Overview of Working Principle
-High cost-effective white light interference film thickness gaugeUsing a broadband light source to illuminate the sample, such as a white light interferometer or spectral reflectometer, the light is reflected at the interface between the air hardened film and the hardened film resin substrate, forming interference signals.
-By analyzing the interference fringes (or phase differences) of the reflection spectrum and combining them with the known refractive index of the film layer, the film thickness can be reflected
-Modern instruments automatically calculate film thickness values by fitting the entire spectral curve, without the need for manual interpretation of stripes.
3、 Typical application scenarios
1. R&D stage: Optimize the hardening solution formula, curing process parameters, and quickly verify the film thickness effect under different processes
2. Incoming inspection: Check whether the hardened film of the purchased semi-finished lenses meets the standard
3. Production process control: online or offline sampling to ensure batch consistency
4. Failure analysis: When there are problems such as detachment and fogging of the lens, trace back to see if the film thickness is abnormal
4、 Example of Operation Process
1. Sample preparation: Clean the surface of the lens to ensure there are no fingerprints or dust;
2. Parameter setting: Enter the type of hardening film material (such as SiO?)? ， N ≈ 1.46) or calibrate the refractive index using a standard plate;
3. Place the sample: Place the lens on the stage and align it with the measurement area (center or edge);
4. Automatic measurement: The instrument collects spectra and calculates film thickness in real-time;
5. Data output: Display numerical values, save reports, support SPC statistical analysis.
Note: For high curvature lenses, some devices are equipped with autofocus and surface compensation algorithms to ensure measurement accuracy!
5、 Advantage comparison (vs ultrasonic film thickness gauge)
