Emir BardakçıThe concept of putting a fingerprint scanner on an LCD display panel itself had gained considerable attention, mainly from the mid-range smartphone sector, which could not afford the high prices for OLED panels at that time. Towards the end of 2019-2020, the Redmi brand from Xiaomi showed off this idea with the Redmi Note 8 Pro, which used an LCD in-display fingerprint solution that was made possible by Tianma.
Technological Difficulty of LCD In-Display Fingerprint Solution
In contrast to OLED screens, the LCD screen requires a backlight unit with a complex optical stack. In this optical stack, light gets blocked and scattered. This makes the process of capturing biometric information via the screen using optical fingerprint sensors highly challenging.
To resolve this, Tianma modified some of the parts of the LCD stack in order to enable the passage of infrared light more easily. For the Redmi Note 8 Pro prototype, an infrared sensor algorithm combining modified films and backlight units worked in collaboration. Advanced image processing algorithms were applied in order to smoothen noisy fingerprint data from the LCD structure.
Although it was functional in the demos, this technology caused added expense, size, and complexity relative to normal LCD modules.
Market Reality & Strategic Shift by Xiaomi
By 2020, the smartphone industry experienced a rapid evolution that was unforeseen. The price of the AMOLED screen had dropped dramatically, especially in China, enabling manufacturers such as Xiaomi or REDMI to use an AMOLED screen in many models, including low-price ones. In the meantime, the side-mounted capacitive fingerprint scanner gained popularity because of its price advantage and ease of use.
With the Redmi Note 10 lineup, Xiaomi began this pivot in their mid-range offerings toward using AMOLED screens. This helped eliminate the cost-effective rationale for developing complex LCD implementations for in-display fingerprint scanning. This means that their LCD in-display fingerprint project never made it into mass production.
What Happened to Tianma’s Technology?
Even as Tianma had to put its LCD in-display fingerprint solution on the back-burner, the company did not turn its back on research involving sensor integration. The company simply repurposed its know-how to other areas of interest to OLED technology, such as optoelectronic hybrid integration. This technology is employed for sophisticated sensing applications. The current focus of Tianma’s research and development efforts is on OLED technology display panels, as well as automotive display panels and industrial display panels.
Final Assessment
The LCD in-display fingerprint sensor, as seen on the Redmi Note 8 Pro, was a technical prototype, demonstrating the feasibility of the idea. However, due to lower prices of AMOLED screens, simpler ways, or because of Xiaomi’s preference for AMOLED screens, it could not see the light of day. It is a fact, now in 2025, that if any mobile telephone has an LCD display, its fingerprint reader is placed either on the side or on the back. If it is in-display, then it is OLED.
