Display Device Light Sensing Pixels Varying Transmissivity
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Solution Overview
Problem
Existing display devices struggle to effectively recognize fingerprints and sense external light across a wide range of illuminance and luminance values using conventional light sensing methods.
Innovation Solution
A display device incorporating a plurality of unit pixels, each comprising display pixels for emitting red, green, and blue colors, and light sensing pixels with varying light transmissivities to detect light across different luminance and illuminance ranges, allowing for the analysis of light sensing signals to determine external light values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single light sensing pixel with fixed light transmissivity is used, then the device structure is simple, but the light sensing range and accuracy are limited
Solution Approach 1:
The light sensing function is segmented into multiple pixels, each with different light transmissivities. The sensor array is divided into first light sensing pixels (higher transmissivity) and second light sensing pixels (lower transmissivity), allowing each segment to handle specific luminance ranges independently, thereby improving overall measurement precision without requiring a single complex pixel structure
Solution Approach 2:
Different regions of the sensor array are assigned different local qualities in terms of light transmissivity. The first light sensing pixels are designed with higher light transmissivity for detecting low luminance values, while the second light sensing pixels have lower light transmissivity for detecting high luminance values, enabling optimized performance across different lighting conditions
2Adaptability or versatility
If light sensing pixels with different light transmissivities are used to detect wider luminance range, then the light sensing range is improved, but the device complexity increases
Solution Approach 1:
The sensor array is segmented into functionally distinct pixel groups - first light sensing pixels for low luminance detection and second light sensing pixels for high luminance detection. This segmentation allows the system to cover a wide luminance range by activating appropriate pixel groups based on lighting conditions, achieving versatility without requiring every pixel to handle all ranges
Solution Approach 2:
The light transmissivity parameter is varied across different pixel types to optimize detection capabilities. By changing the light transmissivity parameter during the manufacturing process (through different color filter layer configurations), the system achieves multiple detection ranges without adding complex electronic control mechanisms
3Reliability
If multiple light sensing pixels with different light transmissivities are implemented, then fingerprint recognition accuracy is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The manufacturing process utilizes parameter changes in the color filter layer configuration to create pixels with different light transmissivities. By varying the color filter layer structure (e.g., using different colors or layer combinations) during standard fabrication processes, the system achieves differentiated pixel performance without requiring separate manufacturing lines or complex additional steps
4Illumination intensity
If a single light transmissivity is used for all light sensing pixels, then the manufacturing process is simple, but the ability to detect external light across wide illuminance range is limited
Solution Approach 1:
The light sensing pixels are segmented into two functional groups with different light transmissivity characteristics. This segmentation enables the system to detect external light across a wide illuminance range by selecting appropriate pixel groups for different lighting conditions, achieving extended detection capability without requiring a single overly complex pixel design
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 proposed solution enhances the light sensing efficiency and accuracy of display devices by enabling the detection of external light across a wide range of luminance and illuminance values, thereby improving fingerprint recognition and overall device performance.
Implementation Method 1
The light sensing pixel in one of the plurality of unit pixels and the light sensing pixel in another one of the plurality of unit pixels may have different light transmissivities for external light
Data Source
AI summary
A display device includes a display part including multiple unit pixels, each of the unit pixels including multiple display pixels and a light sensing pixel, multiple touch electrodes disposed between the display pixels and the light sensing pixel, surrounding circumferences of the display pixels and the light sensing pixel, and sensing a touch, and a main driving circuit sensing a fingerprint by the light sensing pixel. The light sensing pixel in one of the unit pixels and the light sensing pixel in another one of the unit pixels have different light transmissivities for external light, and the main driving circuit analyzes light sensing signals of the light sensing pixels having the different light transmissivities to detect a luminance value or an illuminance value of the external light.