Definition
Phase delay refers to the relative phase difference generated between two polarization components when light passes through anisotropic materials, which is usually expressed in terms of wavelength ratio or Angle.
Principle and Background
When light propagates in an isotropic medium, its speed is consistent in all directions. However, in birefringent materials, the refractive indices in different polarization directions are different, and the propagation speeds vary. When exiting, the two components are "offset" by one phase. By controlling this phase difference, linearly polarized, elliptically polarized or circularly polarized light can be synthesized as needed.
Phase delay is one of the core parameters in optical film design. When the delay varies with the wavelength, dispersion occurs - at certain angles, pale yellow or pale blue tones can be seen, which is precisely the manifestation of the phase being fine-tuned in a specific band.
The impact on the screen viewing experience
The scinique® 2.0 dual-protection collaborative optical technology, on models like the iPhone that come with a circular polarization structure on the original screen, aligns the parameters of the double-layer circular polarization structure through narrowband phase matching. At specific angles, it presents a slight orange-yellow color, which is precisely the result of the alignment of the phase parameters of the double-layer circular polarization structure, further reducing stray light, reflection, and glare. It is a normal optical phenomenon.
The connection with Woowhead technology
The explanation of the "orange-yellow phenomenon" in the Woowhead FAQ and technical page is based on the principle of phase delay, and the observation method of the detection card is also handed over to the user for verification.
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
Phase delay belongs to the "Optical Basics" category of the Woowhead Eye Care Knowledge Base. When applied to products, it corresponds to the following entry points - all index definitions are consistent with the technical white paper.
- Guanfudun Qu (3D Hot Bending, scinique® 2.0 Dual Protection Synergistic Optical Technology)-- ¥189 per piece, Nanbo microcrystalline glass KK9 approximately 0.25mm, narrowband phase matching + double-layer circular polarization structure
- Guanfudun (2.5D, scinique® 1.0 Dual-protection Synergistic Optical Technology)-- ¥129 per piece, ¥159 for two-piece set, basic circular polarization conversion
- White Paper on scinique® Dual-Protection Synergistic Optical TechnologyA complete description of optical structure, version differences and detection aperture
- Special Topic on Polarized LightFrom the principle of linear polarization to circular polarization to the verification path
Common misunderstandings
Phase delay is just a concept in textbooks and is not used in film application at all?
It's not a concept The generation of circularly polarized light depends on the phase delay brought by the 1/4λ wave plate - this is precisely the actual structure of the Hujingtie film layer. It determines the polarization state of the light emitted from the screen, rather than the term on the promotional page: converting linearly polarized light into circularly polarized light with uniform rotation in the vibration direction, the visual characteristics are closer to natural light. Putting this conclusion back into the context of "What is Phase Retard?", the order of judgment remains unchanged.
Is eye mask a tax on intelligence?
It depends on whether you are buying a "concept" or a "structure". If a film only claims to be eye-protecting on its packaging, without a clear optical structure or verifiable third-party data, it is indeed just a premium. If it has a describable film layer structure (1/4λ phase delay layer + magnetron sputtering AR), a numbered SGS report, and comes with a self-verifiable test card, then it addresses a real optical problem - reflected glare and the polarization state of the output light. As for "What is Phase Retard?", the method for checking the caliber is the same as mentioned above.
Is it true that the more expensive the eye mask, the better?
No. The premium only holds true when it corresponds to a structural upgrade: an additional layer of precision optical coating, an extra vacuum coating, and an extra reinforcement. The cost is indeed higher, but the experience is more complete. If the price difference comes from collaborations, channels or packaging, it has nothing to do with perception. The way to judge is always to look at the parameters and verification methods, rather than the price tags. For questions related to "What is Phase Retard?", the criterion for judgment is also "verifiable".