LCD Optical Sensor Layout for Narrow-Bezel Biometric Detection
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Solution Overview
Problem
There is a demand for liquid crystal display devices with built-in optical sensors to have a narrow frame while maintaining effective biometric information detection capabilities.
Innovation Solution
The integration of a collimating layer and optical sensors within the display device to parallelize incident light, combined with a driver IC for signal processing, allows for accurate biometric detection without increasing the frame size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If optical sensors are integrated into the liquid crystal display device, then biometric information detection capability is improved, but frame size increases
Solution Approach 1:
The optical sensor is merged with the liquid crystal display structure by integrating it into the first substrate, sharing common components such as the backlight unit and control circuits. This combining approach enables biometric detection functionality without requiring separate housing space, thus avoiding frame size increase
Solution Approach 2:
The display device is designed to serve multiple functions: displaying visual information through the liquid crystal display and detecting biometric information through the integrated optical sensor. The first substrate simultaneously supports both display pixel structures and sensor structures, making the device universal and eliminating the need for additional frame space
2Measurement precision
If a collimating layer is added to parallelize incident light, then measurement precision is improved, but device complexity increases
Solution Approach 1:
A collimating layer is introduced as an intermediary optical element between the backlight unit and the optical sensor. This layer parallelizes the incident light before it reaches the sensor, improving measurement precision by ensuring uniform light illumination on the detection surface
Solution Approach 2:
The collimating layer is nested within the existing display structure, positioned between the backlight unit and the optical sensor layers. By embedding this optical element within the multi-layer display construction rather than adding it externally, the patent achieves light parallelization without proportionally increasing overall device complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate detection of biometric information such as fingerprints and vein patterns while maintaining a narrow frame, enhancing the functionality of liquid crystal displays.
Implementation Method 1
an optical sensor including a photoelectric conversion element that outputs a detection signal in response to light incident from a liquid crystal layer side
Implementation Method 2
The integration of a collimating layer and optical sensors within the display device to parallelize incident light
Data Source
AI summary
According to one embodiment, a liquid crystal display device with an optical sensor includes a display panel and a driver IC. The display panel includes first to third signal lines, an optical sensor including a photoelectric conversion element, and a sensor signal line that is connected to the optical sensor and transmits a detection signal to the driver IC. One first wiring line drawn from one terminal of the driver IC is connected to four switching elements. Three of the four switching elements are electrically connected to one of the first to third signal lines, respectively. One of the four switching elements, different from the three switching elements, is electrically connected to the sensor signal line.