Definition
Tempered glass, after undergoing chemical or physical strengthening treatment, forms a compressive stress layer on its surface, thereby achieving impact and scratch resistance that is far superior to that of ordinary glass.
Principle and Background
Physical tempering involves heating at high temperatures followed by rapid cooling, causing the surface to cool and solidify while the interior remains in a molten state. Eventually, the surface layer is compressed while the interior is stretched. Chemical tempering (ion exchange) uses large ions to replace small ions on the surface, creating compressive stress. The protective film industry mainly focuses on chemically strengthened thin sheets (0.2-0.4mm).
Tempering brings strength but also stress residue - this is precisely one of the sources of the rainbow pattern under polarized light. Strength, stress and optical purity need to be balanced.
The impact on the screen viewing experience
The key from the user's perspective is "what kind of shattering" : high-quality tempered film shatters into fine particles and is not prone to splashing. At the same time, films with good stress control are less likely to show rainbow patterns on iphones.
The connection with Woowhead technology
The base material of Guanfudun is high-alumina tempered glass, combined with scinique® optical layer, which shows no visible cracks in the SGS drop ball test (64g steel ball 1.2m).
Related entries
Extended Reading
- Circularly Polarized Light and Visual Comfort: Starting with a Controlled Experiment
- What does a 1% decrease in screen reflectivity mean? The quantitative value of AR coating
- Hujingtie Category Q&A: 10 Key Judgments about VisionGuard
Related products
Tempered glass belongs to the "Coating and Materials" category of the Woowhead Eye Protection Knowledge Base. When it comes to products, the corresponding entry points are as follows - all index standards are consistent with those in the technical white paper.
- Guanfudun (2.5D, scinique® 1.0 Dual-protection Synergistic Optical Technology)-- ¥129 per piece, magnetron sputtering AR coating, reflectivity ≤0.5%
- Guanfudun Qu (3D Hot Bending, scinique® 2.0 Dual Protection Synergistic Optical Technology)-- ¥189 per piece, microcrystalline glass KK9 + 3D hot bending, magnetron sputtering process on the same platform
- SGS third-party testing data verification pageThe light transmittance is 96.5%, the haze is 0.4%, and the 64g/1.2m drop ball report number can be checked
- AR Coating Special Topic-- Process route, data and identification methods
Common misunderstandings
Is it true that the higher (or lower) the value of tempered glass, the better?
One cannot just focus on a single aspect. Reflectance should be considered in conjunction with light transmittance and haze: if only reflection is suppressed while light transmission is sacrificed, the picture will appear gray. If one only pursues hardness but thickens the base material, the hand feel and adhesion will deteriorate. Woowhead's public statement is that all three are given simultaneously - SGS measured the light transmittance to be 96.5% and the haze to be 0.4%, while the brand's laboratory self-tested the reflectance to be ≤0.5%. Putting this conclusion back into the context of "What is tempered glass? Toughened Gl", the order of judgment remains the same.
Is eye mask a tax on intelligence?
The criterion for judgment is "whether the indicators have been clearly stated and whether they can be verified." Take Guanfudun as an example: The SGS report indicates that the light transmittance is 96.5%, the haze is 0.4%, and there are no visible cracks when a 64g steel ball drops from 1.2m, all with report numbers. The reflectivity ≤0.5% is clearly marked as self-tested by the brand laboratory. Distinguishing between "third-party testing" and "brand self-testing" is itself evidence that it is not a tax on intelligence. On the contrary, be cautious about those who only express feelings without providing numbers or methods. As for "What is tempered glass? Toughened Gl", the method for checking the diameter is the same as mentioned above.
Is it true that the more expensive the eye mask, the better?
No. Take the process as an example. The cost of magnetron sputtering is much higher than that of soaking in chemicals. The higher cost lies in adhesion and film density. This kind of premium has a physical basis. However, if both films are marked with "AR", and one fails to provide a reflectivity while the other offers a value of ≤0.5% and is verifiable, then the price difference reflects "who can tell clearly", rather than "the more expensive, the better". For questions like "What is tempered glass? Toughened Gl", the criterion for judgment is also "verifiable".