Backlight Module Fingerprint Sensor Integration for Screen Ratio
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Solution Overview
Problem
Conventional LCD devices face a limitation in screen ratio due to the combination of a transparent cover and an opaque fingerprint sensor in non-display areas, which obstructs the display functionality.
Innovation Solution
Integrating the fingerprint sensor within the backlight module of the LCD device, allowing it to be positioned under the display panel without interfering with the display, and using translucent or transparent components to maintain uniform light intensity and enable fingerprint recognition within the display area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fingerprint sensor is placed in the non-display area, then the fingerprint recognition function is achieved, but the screen ratio is limited
Solution Approach 1:
The patent merges the fingerprint sensor with the backlight module by integrating the fingerprint sensor substrate with the backlight structure. The fingerprint sensor is positioned between the diffusion sheet and the light source, allowing it to share the same space as the backlight components. This integration enables the fingerprint recognition function while eliminating the need for separate non-display area placement, thereby increasing the screen ratio.
2Measurement precision
If the fingerprint sensor is made opaque, then the fingerprint recognition accuracy is improved, but the light intensity uniformity deteriorates
Solution Approach 1:
The patent applies local quality by making only the fingerprint sensing region opaque while keeping the surrounding areas transparent. The fingerprint sensor substrate is designed with selective opacity - the area corresponding to the fingerprint sensing region blocks light to enhance contrast and recognition accuracy, while other regions remain transparent to maintain uniform light distribution across the display.
3Area of stationary object
If the fingerprint sensor is integrated in the backlight module, then the screen ratio is enhanced, but the structural complexity increases
Solution Approach 1:
The patent achieves multi-functionality by designing the backlight module to serve dual purposes: providing illumination for the display and housing the fingerprint sensor. The backlight structure is configured to accommodate the fingerprint sensor substrate, allowing it to function as both a light source and a fingerprint recognition component. This universal design eliminates the need for separate structural elements, thereby reducing overall complexity despite the integrated functionality.
Data Source
AI summary
An LCD device defining a display area includes a backlight module for providing light, an LCD panel stacked on the backlight module, and a fingerprint sensor in the backlight module. The fingerprint sensor is positioned in the display area and defines a fingerprint sensing area in the display area.