Sensor Light-Shielding Layer for Display Device Noise Reduction
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Solution Overview
Problem
Optical sensors in display devices with built-in sensors, such as fingerprint or vein sensors, face noise interference from light other than the reflected light, which degrades detection accuracy.
Innovation Solution
Incorporating a collimating layer and light-shielding layers in the display device to block angled light and prevent optical leakage, ensuring that only parallel incident light reaches the sensor, thereby enhancing detection signal accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the sensor is placed in the display area to enable biological information detection, then the functionality of the display device is enhanced, but noise from non-reflected light degrades detection accuracy
Solution Approach 1:
A light-shielding layer is introduced as an intermediary component between the illumination device and the sensor. This layer selectively blocks light paths that would cause noise while allowing the intended reflected light from the target object to reach the sensor, thereby resolving the contradiction between enabling detection functionality and maintaining detection accuracy
Solution Approach 2:
The light-shielding layer is divided into multiple regions with different functions: a first light-shielding region that blocks light from reaching the sensor directly, and a second light-shielding region that blocks light from reaching the channel area of the switching element. This segmentation allows precise control over light paths to eliminate noise sources while preserving the detection function
2Measurement precision
If light-shielding layers are added to block noise light, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The light-shielding layer serves multiple functions simultaneously: it blocks noise light from reaching the sensor, blocks light from reaching the channel area of the switching element to prevent optical leakage, and is integrated into the existing display device structure. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving improved detection accuracy
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
This configuration improves the accuracy of biological information detection by minimizing noise from non-parallel light, leading to better fingerprint and vein image recognition.
Implementation Method 1
an optical sensor that uses a photoelectric conversion element is employed
Implementation Method 2
The sensor light-shielding layer is opposed to a channel area formed in a semiconductor layer included in the switching element, and blocks light from the illumination device on the channel area
Data Source
AI summary
According to one embodiment, a display device includes a first substrate, a second substrate, a liquid crystal layer and an illumination device. The first substrate includes a base, a sensor, a sensor circuit and a sensor light-shielding layer. The sensor is located between the base and the liquid crystal layer in a display area that includes pixels, and outputs a detection signal corresponding to light becoming incident from a side of the liquid crystal layer. The sensor circuit includes a switching element and is connected to the sensor. The sensor light-shielding layer is opposed to a channel area formed in a semiconductor layer included in the switching element, and blocks light from the illumination device on the channel area.