AAPL was downgraded this week due to an analyst claiming that Apple was ditching an all-glass iPhone.
Was an all-glass iPhone on anyone’s radar? All I’ve heard about was a foldable iPhone.
-awlabrador
No, but it’s a brilliant idea if you’re from the “designed obsolescence”school.
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What does “all glass” even mean? Don’t iPhones have a glass front AND a glass back now? Does it mean no metal border/edge between them? Sounds like an incredibly stupid idea considering how breakable they will be (planned obsolescence arguments aside).
And of course, there’s a counter-rumor:
Apple is well-known for their love of the incorporation of unique and functional materials into their hardware designs, so I really hope someone at Apple is looking into making an all-metal phone - “Unapologetically Aluminum” anyone? (harkening back to their robust but short lived “Beautifully, Unapologetically Plastic” iPhone 5C model from 2013: Apple's New iPhone 5C Is PLASTIC, 'Beautifully, Unapologetically Plastic' - Business Insider):
Applications
Aluminium oxynitride is used for infrared-optical windows, with greater than 80% transparency for 2 mm thickness at wavelengths below about 4 micrometers, dropping to near zero at about 6 micrometers.[8] It has also been demonstrated as an interface passivation layer in some semiconductor-related applications.[9]
Aluminium oxynitride has less than half the weight and thickness of glass-based transparent armor.[10] Aluminium oxynitride armor of 1.6-inch (41 mm) thickness is capable of stopping .50 BMG armor-piercing rounds, which can penetrate 3.7 inches (94 mm) of traditional glass laminate.[8][11]
In 2005, the United States Air Force began testing aluminium-oxynitride-based armor.[12]
Well, my 15 Pro Max seems to, but I have always used a minimalist, clear case on all the iPhones over the years, somehow a tiny chip on one long ago, o I’ll do the same in the future, without the case, it’s just too slippery, slides off my recliner’s arm just setting there! Slips between the cushion, etc…I just want it slim enough for a shirt pocket, so not too heavy, ever…
So, watching, waiting to see where they go, folding, no interest, another problem for case designers!
Adding an idea: ok, maybe making the front display screen out of aluminum oxynitride (marketed under the name ALON by Surmet Corporation) won’t work for some reason (relating to touch sensitivity, etc), but why not make the rest of the phone out of ALON, including the sides? Or make it a “unibody” shallow dish design - a la the iPhone 5C - with a normal glass display top? Surely that’s got to be possible. Maybe cost is prohibitive at scale? But, heck, being able to legitimately claim that the iPhone body is made of “transparent aluminum” is marketing gold!
Also, ALON does seem to be pretty “workable” into various shapes. From Wikipedia:
Aluminium oxynitride (marketed under the name ALON by Surmet Corporation[3]) is a transparent ceramic composed of aluminium, oxygen and nitrogen. Aluminium oxynitride is optically transparent (≥80% for 2 mm thickness) in the near-ultraviolet, visible, and mid-wave-infrared regions of the electromagnetic spectrum. It is four times as hard as fused silica glass, the same hardness of 9 as sapphire, and nearly 115% as hard as magnesium aluminate spinel. It can be fabricated into transparent windows, plates, domes, rods, tubes, and other forms using conventional ceramic powder processing techniques.[4]
Sadly, my ALON iPhone dream seems like a non-started. I had a conversation with Gemini and it provided several apparent deal-breakers, but I’d still like to see what a team of brilliant engineers could do! From Gemini:
Even if cost were no object, and even if you expertly integrated embedded antenna bands and wireless charging elements directly into the case, a smartphone display and body made entirely out of ALON would still face several critical material and engineering failures.
While it sounds like the ultimate sci-fi chassis, ALON introduces severe physics penalties regarding weight, acoustics, thermal management, and RF interference.
1. Ergonomics: The “Brick” Penalty
ALON is incredibly dense compared to the materials used in modern smartphones.
The Math: ALON has a density of roughly 3.7 g/cm³. For comparison, standard smartphone Gorilla Glass is about 2.4 g/cm³, and aerospace-grade titanium is around 4.5 g/cm³.
The Reality: A modern smartphone uses thin glass for the screen, but the rest of the internal volume is filled with lightweight plastics, lithium batteries, and hollow spaces. If you machined a unibody phone frame and thick rear plate entirely out of solid ALON ceramic to maintain its structural integrity, the device would weigh nearly twice as much as a standard phone. It would feel less like a sleek gadget and more like a literal stone brick in your pocket.
2. Thermal Management: A Thermal Insulator Envelope
Smartphones rely on their chassis to act as a giant heat sink. The aluminum, titanium, or thin glass backs of modern phones quickly pull heat away from the processor (CPU) and dissipate it into the air or your hand.
ALON is a ceramic with relatively low thermal conductivity compared to metals. Encasing a high-performance modern processor inside a thick shell of ALON would essentially create an insulated oven. Without an actively cooled metal frame to pull heat away, the phone’s processor would rapidly overheat under basic loads (like gaming or video recording), forcing the phone to severely throttle its performance or shut down entirely.
3. High Dielectric Constant: Even Isolated Antennas Suffer
While embedding an isolated metal antenna band into the case seems like a clean workaround for a solid shell, ALON’s fundamental electromagnetic properties would still degrade performance.
ALON has a remarkably high dielectric constant (relative permittivity) of around 9.3 (compared to air at 1.0, or standard plastics/glass at 3.0 to 4.5). A high dielectric constant means that any electromagnetic fields passing near or through the ALON body are heavily altered.
It would severely detune nearby antennas, forcing engineers to radically change the antenna shapes.
It creates high capacitive loading. If your hand grips the ALON body, the interaction between your hand, the high-dielectric ceramic, and the internal components would cause severe signal attenuation (the infamous “death grip” phenomenon on steroids), affecting 5G, Wi-Fi, and Bluetooth.
A wireless charging plate trying to push power through a thick layer of a material with a dielectric constant of 9.3 would suffer from massive energy efficiency losses, generating even more internal heat.
4. Acoustic Deficiencies: The “Dead” Speaker
Modern smartphones increasingly use the body of the phone and the display glass itself as a secondary acoustic transducer (vibrating the screen to produce earpiece audio or bass amplification).
Because ALON is an extremely rigid ceramic with immense elastic modulus, it requires significantly more energy to vibrate than glass or thin metal. If you tried to use standard internal microscopic speakers, the sound would be heavily muffled, tinny, and trapped inside the chassis. Machining deep, complex acoustic chambers or speaker speaker-grill micro-perforations into ALON is practically impossible due to its extreme hardness—it destroys conventional CNC tooling.
5. Brittle Failure and Internal Shock
While ALON is incredibly scratch-resistant and withstands blunt impact (like a bullet) by distributing energy across its polycrystalline structure, it is still a ceramic. It does not deform or bend; it behaves elastically until it reaches its breaking point, and then it fractures completely.
If a solid ALON phone were dropped onto a concrete sidewalk from pocket height:
The outside of the phone might not look scratched or cracked.
However, because ALON is so rigid, it has poor mechanical damping. It would pass 100% of the kinetic shock directly through the chassis into the delicate internal silicon chips, solder joints, and battery layers. Your phone’s exterior would look pristine, but the electronics inside would be shattered or jarred loose from the impact.
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Well, that seems to be a deal killer in so many ways! And costly as well, I suspect… Overcoming those limitations seems beyond our tech today…