Display Subsidewall Light Attenuation for Fingerprint Sensors
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Solution Overview
Problem
Fingerprint detection in display substrates is hindered by the superposition of images from friction ridges and internal structures due to light reflection, which affects the accuracy of fingerprint recognition.
Innovation Solution
A display substrate design featuring a pinhole layer and a sidewall that attenuates light transmission, allowing only reflected light from the finger to reach the image sensor while blocking light from internal structures, thereby enhancing fingerprint detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light transmission through the display substrate is allowed for image sensor operation, then fingerprint detection function is enabled, but light reflection from internal structures causes image superposition and reduces detection accuracy
Solution Approach 1:
The patent extracts and removes the harmful reflected light from the optical path by introducing a light absorbing structure that selectively absorbs light reflected from internal structures before it reaches the image sensor. This separates the useful light (from friction ridges) from harmful light (reflected internal structure light), resolving the image superposition problem.
Solution Approach 2:
The light absorbing structure acts as an intermediary element positioned between the internal structures and the image sensor. It mediates the optical interaction by selectively absorbing harmful reflected light while allowing useful light to pass through, thereby improving fingerprint detection accuracy without blocking the necessary optical path.
2Measurement precision
If a light absorbing structure is added to block internal light reflection, then fingerprint image clarity is improved, but device structure complexity increases
Solution Approach 1:
The light absorbing structure is merged with existing internal structures of the display substrate, such as being formed on or integrated with the thin-film transistor layers. This combination approach adds the light absorption function without requiring a completely separate structural component, thereby minimizing the increase in device complexity.
Solution Approach 2:
The light absorbing structure serves multiple functions: it absorbs reflected light from internal structures to improve image clarity, and can be integrated with existing functional layers of the display substrate. This multi-functionality reduces the need for additional separate components, keeping the overall structure relatively simple.
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
The solution effectively reduces internal light interference, improving the clarity of fingerprint images and facilitating more accurate detection by creating a uniform background for enhanced recognition.
Implementation Method 1
a sidewall at least partially surrounding the window; wherein the sidewall is configured to attenuate transmission of light through the sidewall
Implementation Method 2
Fingerprint detection in display substrates is hindered by the superposition of images from friction ridges and internal structures due to light reflection
Implementation Method 3
an image sensor spaced away from the support and optically coupled to the pinhole
Data Source
AI summary
Disclosed herein is a display substrate of a display panel, comprising: a support; a second layer on the support; a window extending through the second layer and optically coupled with an image sensor; and a sidewall at least partially surrounding the window; wherein the sidewall is configured to attenuate transmission of light through the sidewall.