LogCase - 4 Colour (circular) E-Paper Smartphone Case
A round E-Paper display on the back of your iPhone. No battery, no charging.
LogCase 4 Colour (circular) is a protective iPhone case with a circular four-colour E Ink display on the back. Choose any picture in the free LogCase app and tap Send: your iPhone draws it on the case. Once drawn, it stays, with no power at all.
What makes it different
- Four colours: black, white, red and yellow. The app prepares each picture for the panel, keeping contrast and detail. The round display has a higher resolution than the rectangular model.
- No battery: the display refreshes with energy from your iPhone over NFC. There is no battery, port or cable inside.
- Zero power to keep: your picture stays on the case until you change it.
- Real protection: a shockproof case, with the E-Paper module sealed to IPX6.
- Paper-like display: no glare, and easy to read even in bright sunlight.
Compatibility
iPhone 17 Pro and 17 Pro Max. In White Ash or Midnight Blue.
Want more colour? See LogCase Full Colour, with six colours.
Notices
iPhone, MagSafe and iOS are trademarks of Apple Inc., registered in the U.S. and other countries. E Ink is a registered trademark of E Ink Holdings Inc.
LogCase - 4 Colour (circular)
Tap. Refresh. Done.
No cables, no charging, no settings to fiddle with. Your iPhone does all the work.
Pick an image
Choose any photo or artwork in the free LogCase app.
Tap to send
Tap Send in the app. The iPhone inside the case powers the display over NFC and delivers your image.
It stays
E-Paper holds your picture with zero power until you choose to change it.
The details.
Everything inside the case, at a glance.
- Display
- Round E Ink display, four colours (black, white, red, yellow)
- Power
- No battery. Powered by your iPhone's NFC
- Image retention
- Holds your image with zero power
- Water resistance
- E-Paper module sealed to IPX6
- Protection
- Shockproof case design
- Compatible with
- iPhone 17 Pro, 17 Pro Max
- Colours
- White Ash, Midnight Blue
- App
- LogCase for iOS, free on the App Store
Does LogCase have a battery inside? How to charge it?
No, LogCase does not have a battery inside, and it works without one! LogCase's E-Paper module relies on our NFC Energy Harvesting technology.
Please check out our technology page for further details.
How long does an image remain on the LogCase E-Paper display, and will it automatically clear or power down after a specific time?
An E-Paper display is bistable, meaning once an image is written, it stays visible indefinitely without any additional power. The LogCase panel will hold your picture until you choose to refresh or overwrite it. There is no built-in timeout that erases the image after a set period.
Behind the scenes, the microcontroller and driver circuitry can enter a low-power sleep mode (or even switch off entirely) once the update is complete, but the charged pigment particles in the E-Paper layer remain locked in place. This lets the display consume virtually zero energy between updates. In practical terms, your image will stay perfectly legible for months or even years, only disappearing when you send a new image or perform a manual, precise operation.
Does the LogCase E-Paper display images like a traditional LED/LCD screen?
No. The LogCase uses a reflective E-Paper display rather than an emissive LED or backlit LCD. E-Paper works by moving tiny charged particles within each pixel to form an image, and that image remains visible without any power until you choose to update it. This delivers paper-like contrast and excellent readability, even in bright sunlight, while consuming virtually no energy between updates.
Because it isn't backlit or driven at high refresh rates, E-Paper can't show continuous video or rapid animations like an LED/LCD. Instead, it excels at displaying static photos, text or graphics with razor-sharp clarity and minimal power draw.
Can the LogCase E-Paper's palette (black, white, red, yellow, blue, and green) still reproduce other hues?
The LogCase E-Paper panel uses a fixed set of pigments: black, white, red and yellow on the four colour model, plus green and blue on the full colour model. It cannot create new pigments, but our iOS app extends the palette visually. Before sending an image to the display, the app converts each target hue into fine patterns of the available pigments using error-diffusion dithering and halftoning. For example, yellow and black dots blend into green at normal reading distance. This simulates intermediate hues such as greens, oranges and soft pastels, while keeping the ultra-low-power, high-contrast benefits of a reflective display.
What is the difference between E Ink and E-Paper?
E-Paper, or electronic paper, is the general name for displays that reflect light like paper and keep a picture without power. E Ink is the company that invented the technology and makes most E-Paper panels, so the two names are often used for the same thing. LogCase uses E Ink panels: Spectra 6 on LogCase Full Colour, and four-colour panels on the 4-colour models.
Read more in Understanding E-Paper.
Which iPhone models does LogCase fit?
LogCase Full Colour fits iPhone 17 Pro, 17 Pro Max, 18 Pro and 18 Pro Max. LogCase 4 Colour (circular) fits iPhone 17 Pro and 17 Pro Max. LogCase 4 Colour (rectangle) fits iPhone 16 Pro and 16 Pro Max.
Is the LogCase app free?
Yes. The LogCase app is free on the App Store, with no subscription. You use it to choose a picture and cast it to your case. It requires iOS 27 or later.
