E-Bike: Sunlight-Readable 3.5-Inch TFT Display
More Performance and Functionality in a Slim Display Design
FLYER stands for high-quality e-bikes with innovative technology and a high level of riding comfort. The existing display was to be fundamentally redesigned for various FLYER models. Depending on the model, the new HMI is now used either as the optional “FIT Display Comfort” or as standard equipment on higher-end versions.
The aim of the redesign was to significantly improve optical performance and appearance, integrate additional functions and, at the same time, achieve a price level comparable to that of the previous display.
The Display Requirements
The main focus was on reliable readability under a wide range of conditions, particularly in direct sunlight and from different viewing angles. At the same time, FLYER wanted a slimmer bezel design that would integrate seamlessly and elegantly into the e-bike cockpit.
Key Requirements Included:
The Technical Solution
Based on a standard 3.5-inch IPS TFT display, an individual solution was developed through targeted customer-specific adaptations. Due to outdoor use, the brightness was increased to 1,000 cd/m². An optically bonded cover lens reduces distracting reflections, improves contrast and ensures optimal readability even under challenging lighting conditions. In addition, AR and AF coatings are used to reduce reflections and protect the surface against fingerprints.
A customised integrated light sensor enables automatic adjustment of the display brightness to the ambient lighting conditions. An RGB LED adds an intuitive status indicator to the display. The solution thus combines high optical quality with enhanced functionality and a modern appearance, optimally tailored to the requirements of the application.
Challenges in Development and Series Production
The slim bezel design placed high demands on the sealing of the HMI. Various adhesive bonds were tested in several testing and optimisation cycles until water ingress could be reliably prevented.
Integrating the TFT, backlight, light sensor and RGB LED on a single FPC was also challenging. The solder joints required for this occasionally led to quality deviations during series production and required consistent claims and quality management.
During the component shortage, the limited availability of the light sensor and display controller made procurement more difficult. Several alternative components had to be evaluated and qualified, resulting in additional variants and part numbers. As procurement was handled through a Chinese assembly partner, coordination regarding quality, claims and pricing was also complex.
The new display meets the original customer requirements without any deviations: It offers excellent readability, wide viewing angles and additional intelligent functions in a slim, high-quality design. The result is a powerful HMI solution that makes the quality standards of FLYER e-bikes visible in the cockpit as well.