Every outdoor product eventually confronts the same display question: how do you keep a screen readable at high noon? The answer that keeps winning is not a brighter backlight — it is better black-and-white.
Three families of low-power monochrome
Segment LCDs are the cheapest and fastest to drive but can only show fixed shapes — fine for digits, useless for arrows and maps.
Memory-in-pixel (MIP) panels put a tiny SRAM cell behind each pixel, so the panel holds an image with no refresh current. They animate slowly — one to a few frames per second — but for turn-by-turn arrows that is exactly the right tempo.
Transflective TFTs use ambient light through a reflective layer plus a modest backlight for darkness. They render graphics properly and stay readable in sun, at a higher drive cost than MIP but far below a backlit colour TFT at outdoor brightness.
Why “black and white only” is a design gift
Two-tone constraints force high-contrast artwork: bold arrows, big numerals, iconographic turns. That style happens to be what a rider or cyclist can parse in a 300-millisecond glance. Teams that design the UI natively in two tones produce better products than teams that design in colour and convert.
The trade-offs to plan for
Ghosting and slow transitions on some panel families; temperature-dependent contrast; artwork pipelines that need 1-bit masters; and bezel bonding choices that affect both readability and sealing. None of these is a blocker — they are just decisions that must be made early, because they touch the enclosure, the firmware and the art at the same time.