How the Keefrash E Ink Phone Case Works | NFC + E Ink Explained Simply
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**How the Keefrash E Ink Phone Case Works
A Simple NFC + E Ink Technology Breakdown**
Most phone cases are passive accessories.
Keefrash turns the back of your phone into a customizable paper-like display—with no battery required.
Here’s how it works.
1. Why the Keefrash case doesn’t need a battery
The display on the back uses E Ink technology, the same type found in Kindle e-readers.
E Ink advantages:
· Uses almost no power once an image is displayed
· Only consumes energy during a refresh
· Stays visible even if the phone dies
· Clear outdoors, no glare, gentle on the eyes
Once an image appears, it stays there until you decide to change it.
2. How images are transferred from your phone (NFC)
Keefrash uses NFC, not Bluetooth or Wi-Fi.
Inside the case is a custom NFC coil.
When your iPhone is inside the case, the NFC coil aligns perfectly and allows:
· Short-range data transfer
· A tiny burst of energy to refresh the E Ink screen
There is no internal battery.
The display borrows just enough energy from your iPhone during a refresh.
Important: Install the case first, then open the Keefrash app.
Without the case on, the iPhone can’t detect the E Ink module.
3. Why the refresh animation looks like a “developing photo”
E Ink displays move microscopic pigment particles instead of lighting pixels.
This creates a fade-in, paper-like refresh effect that feels organic and satisfying.
It’s part of the charm of electronic paper.
4. Why Keefrash uses a 4.0” 528×768 display
Many generic “4-inch” displays are actually:
· 3.97 inches
· 480×800 resolution
Keefrash designed a 4.0-inch, 528×768, +5.6% more pixels module optimized for phone-back proportions.
This delivers:
· Crisper details
· Better color depth (4-color: black, white, red, yellow)
· More balanced image framing
Your phone’s back simply looks better.
5. Privacy: your photos stay on your phone
The Keefrash app transfers images directly via NFC.
· No cloud upload
· No server storage
· No account required
· Fully local processing
Your photos stay private—on your device only.
6. One Keefrash App, worldwide compatibility
Powered by SUMMITMOB, INC., the Keefrash ecosystem uses a unified global app.
Whether you're in the US, Japan, or Europe, you get the same:
· App interface
· NFC communication method
· Display behavior
· Device compatibility
This ensures long-term updates and a consistent user experience.
The idea behind Keefrash
The front of your phone is smart.
The back should be, too.
Keefrash turns your phone into:
· A digital canvas
· A personal mood board
· A zero-power display
· A space to show what matters to you
Not just a phone case.
A second screen for your personality.