Display Device Sensor Circuit Layout for Biometric Sensing
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Solution Overview
Problem
Integrated photo sensors in display devices suffer from insufficient light receiving areas due to integration with pixels, leading to decreased light emitting areas and image quality issues like horizontal line blur caused by capacitance differences between scan lines.
Innovation Solution
Incorporating dummy sensor circuits with a similar structure to sensor circuits in areas where existing sensor circuits are removed, and connecting multiple light receiving elements to a single sensor circuit to enhance light receiving capacity while minimizing capacitance differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensor circuits are integrated with pixel circuits in display devices, then biometric sensing function is achieved, but light receiving area is insufficient
Solution Approach 1:
The display device is divided into multiple pixel rows, with alternating rows containing sensor circuits for biometric sensing. This segmentation allows sensor circuits to be distributed across the display area, increasing the total light receiving area while maintaining the biometric sensing function. The dummy sensor circuits are placed in non-display areas to maintain structural symmetry without interfering with the sensing function.
2Quantity of substance
If multiple light receiving elements are connected to a single sensor circuit, then light receiving capacity is enhanced, but capacitance differences between scan lines increase
Solution Approach 1:
Different regions of the display device have different configurations: sensor circuits are placed only in specific pixel rows (e.g., even-numbered rows) while odd-numbered rows contain dummy sensor circuits. This local differentiation allows multiple light receiving elements to be connected to sensor circuits in regions where it benefits the sensing function, while avoiding capacitance issues in regions where display performance is critical.
Solution Approach 2:
Dummy sensor circuits are created as copies of the actual sensor circuits, placed in non-display areas or alternating pixel rows. These dummy circuits have the same structural characteristics as real sensor circuits, which helps maintain uniform capacitance distribution across scan lines while not interfering with the actual biometric sensing function.
3Manufacturing precision
If sensor circuits are placed in alternating pixel rows, then image quality defects are reduced, but device complexity increases
Solution Approach 1:
The display device merges the functions of sensor circuits and dummy sensor circuits into a unified structural framework. Both real and dummy sensor circuits follow the same layout patterns and are controlled by the same scan lines, simplifying the overall circuit arrangement while still achieving the goal of reducing image quality defects through alternating row placement.
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
This approach increases the light receiving amount of photo sensors, improves optical sensing performance, and reduces image quality defects such as horizontal line blur, thereby enhancing the overall image quality of the display device.
Implementation Method 1
first light receiving elements on at least some of the pixel circuits of the first pixel row and the dummy sensor circuits; and second light receiving elements on at least some of the pixel circuits of the second pixel row and the sensor circuits
Data Source
AI summary
A display device includes: pixel circuits arranged in a first direction on each of a first pixel row and a second pixel row; dummy sensor circuits arranged in a predetermined interval between the pixel circuits on the first pixel row; sensor circuits arranged in the interval between the pixel circuits on the second pixel row; light emitting elements disposed on the pixel circuits and connected to each of the pixel circuits; first light receiving elements on at least some of the pixel circuits of the first pixel row and the dummy sensor circuits; and second light receiving elements on at least some of the pixel circuits of the second pixel row and the sensor circuits. One of the sensor circuits is connected to at least two of the first light receiving elements and at least two of the second light receiving elements.