Irregular Photo Sensor Array for Low-Cost Fingerprint Sensing
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Solution Overview
Problem
Current display devices with fingerprint sensors face challenges in achieving high-resolution and accurate fingerprint detection while maintaining low manufacturing costs, as CMOS Image Sensors (CIS) offer faster processing and higher resolution but increase costs when applied to large areas, while TFT sensors provide low-cost but low-resolution implementations.
Innovation Solution
A display device with a photosensitive type fingerprint sensor featuring a plurality of photo sensor units arranged in an irregular pattern on a two-dimensional array, using light emitting elements from the display pixels as a light source, and a light blocking layer with pin holes to selectively pass light, reducing the module thickness and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CIS is applied to large area for high resolution fingerprint sensing, then fingerprint sensing accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The sensor layer is divided into multiple sensor regions with different functions: a first sensor region with first photo sensors for fingerprint sensing and a second sensor region with second photo sensors for other sensing functions. This segmentation allows the high-resolution CIS to be used only where needed (fingerprint area) rather than across the entire large area, reducing manufacturing cost while maintaining fingerprint sensing accuracy.
2Ease of manufacture
If TFT sensor is used for large area implementation, then manufacturing cost is reduced, but fingerprint sensing accuracy deteriorates
Solution Approach 1:
Different regions of the sensor layer have different photo sensor types optimized for their specific functions. The first sensor region uses photo sensors suitable for fingerprint sensing, while the second sensor region uses photo sensors optimized for other sensing functions. This local quality differentiation ensures high fingerprint sensing accuracy in the first region while maintaining cost-effectiveness across the entire large area sensor layer.
3Ease of manufacture
If photo sensor units are arranged in regular pattern, then manufacturing is simplified, but light interference and detection accuracy are reduced
Solution Approach 1:
The photo sensors in the second sensor region are arranged in an irregular pattern rather than a regular grid. This asymmetric arrangement reduces light interference between adjacent photo sensors and improves detection accuracy for non-fingerprint sensing functions, while the first sensor region maintains a regular pattern for fingerprint sensing to simplify manufacturing.
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 enables high-resolution and accurate fingerprint detection with reduced manufacturing costs by utilizing the display pixels as light sources and optimizing the light blocking layer for efficient light passage, expanding the sensing region without increasing costs.
Implementation Method 1
a light emitting element layer provided on the circuit element layer, the light emitting element layer including a plurality of light emitting elements
Implementation Method 2
a sensor layer disposed on the substrate, the sensor layer including a plurality of photo sensor units each including sensor pixels
Implementation Method 3
a light blocking layer with pin holes to selectively pass light
Data Source
AI summary
A display device is provided including a substrate. The substrate includes a display region that includes a plurality of pixels and a sensing region provided in at least one region of the display region. A circuit element layer is disposed on the substrate, the circuit element layer includes a plurality of conductive layers. A light emitting element layer is provided on the circuit element layer. The light emitting element layer includes a plurality of light emitting elements. A sensor layer is disposed on the substrate. The sensor layer includes a plurality of photo sensor units each including sensor pixels. The photo sensor units are arranged in an irregular pattern in the sensing region.