Oblique Fingerprint Sensor Integration in Display Panels
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Solution Overview
Problem
Existing fingerprint sensors on mobile information terminals face challenges in sensing fingerprints on display screens without moire interference, especially when integrated with liquid crystal displays.
Innovation Solution
A display device with a fingerprint sensor attached obliquely to the display panel at a predetermined angle of 20° to 45°, allowing light reflected from the fingerprint to be sensed without interference, and a flexible circuit board mounting the sensor to maintain functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the fingerprint sensor is disposed below the screen area of the liquid crystal display, then the fingerprint sensor can be integrated into the display structure, but moire interference occurs due to the air gaps in the prism sheet structure
Solution Approach 1:
The invention extracts the harmful air gaps from the optical path by removing or modifying the prism sheet structure. The fingerprint sensor is positioned to receive light directly through the liquid crystal display without passing through the prism sheet's air gaps, thereby eliminating the source of moire interference while maintaining sensor integration
Solution Approach 2:
The invention introduces a light guide layer as an intermediary component between the liquid crystal display and the fingerprint sensor. This light guide layer directs light from the display pixels to the sensor without requiring the light to pass through the prism sheet's air gaps, thus preventing moire interference while enabling successful integration
2Object-affected harmful factors
If the fingerprint sensor is disposed in the bezel area outside the screen, then moire interference is avoided, but the bezel area increases
Solution Approach 1:
The invention moves the fingerprint sensor from the traditional bezel area (one-dimensional positioning) to a position below the screen area (two-dimensional positioning). By utilizing the vertical space within the display structure, the sensor is integrated without increasing the horizontal bezel dimensions, thus avoiding moire interference while maintaining compact form factor
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 prevents moire interference, enabling accurate fingerprint sensing on the screen while maintaining the display's integrity and functionality.
Implementation Method 1
a fingerprint sensor coupled to the display panel configured to sense light reflected from the fingerprint on a display area of the display panel
Data Source
AI summary
A display device and a mobile information terminal including the same are disclosed. The display device includes a display panel on which a fingerprint is touched, and a fingerprint sensor coupled to the display panel configured to sense light reflected from the fingerprint on a display area of the display panel. The fingerprint sensor is attached obliquely on the display panel at a predetermined angle to a reference line parallel to a long axis of the display panel.