Light Detection Structure with Reference Circuit for Display Panels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light detection structures in display devices face challenges in maintaining detection accuracy due to manufacturing process drift and environmental temperature changes, leading to inconsistencies in photoelectric curve characteristics.
Innovation Solution
The proposed light detection structure incorporates a test circuit with a photo transistor and an auxiliary transistor connected in series, along with a reference circuit featuring a reference transistor. These transistors have equivalent resistance values that remain consistent under various illumination conditions, ensuring stable signal processing through a signal processor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple photo transistor is used for light detection, then the device complexity is reduced, but the detection accuracy deteriorates due to manufacturing process drift and temperature changes
Solution Approach 1:
The patent creates a reference circuit that copies the electrical characteristics of the photo transistor circuit. By fabricating identical transistor pairs (first and second transistors in the photo transistor circuit, third and fourth transistors in the reference circuit) under the same manufacturing conditions, the reference circuit replicates the manufacturing process drift and temperature effects. This allows the signal processor to subtract the reference signal from the photo transistor signal, eliminating the effects of manufacturing variations and temperature changes, thereby maintaining high detection accuracy without requiring complex calibration procedures.
2Measurement precision
If auxiliary transistors and reference circuits are added to improve detection accuracy, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent merges the reference circuit with the photo transistor circuit by integrating them into a single pixel unit. The reference circuit is positioned adjacent to the photo transistor circuit within the same pixel, sharing common structural elements and fabrication processes. This integration allows the complex functionality of drift compensation to be achieved without adding separate complex subsystems, as the reference circuit serves as an embedded calibration mechanism within the existing pixel structure.
Solution Approach 2:
The patent changes the operational parameters of the transistor circuits by applying different illumination conditions to the photo transistor versus the reference transistors. The photo transistor is exposed to ambient light while the reference transistors are shielded, creating a controlled parameter difference that enables the signal processor to isolate and compensate for manufacturing drift and temperature effects through differential measurement.
3Reliability
If multiple transistor pairs are used to compensate for manufacturing drift, then the reliability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent creates multiple identical transistor pairs that are fabricated simultaneously using the same manufacturing process. The first and second transistors in the photo transistor circuit are designed to be identical in structure and dimensions, as are the third and fourth transistors in the reference circuit. By copying the same transistor design multiple times under identical manufacturing conditions, the patent ensures that all transistors experience the same process variations, allowing these variations to be canceled out through differential measurement rather than requiring ultra-precise manufacturing control.
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 configuration enhances the stability of the signal obtained by the signal processor, reducing the impact of manufacturing process variations and environmental temperature changes, thereby improving the detection accuracy of ambient light conditions.
Implementation Method 1
the photo transistor is configured to receive an ambient light signal
Data Source
AI summary
The application relates to a light detection structure, a display panel and a display device. The test circuit includes a photo transistor and an auxiliary transistor that are connected in series; the reference circuit includes a reference transistor; equivalent resistance values of the photo transistor, the auxiliary transistor and the reference transistor are same; a control end of the test circuit is connected with a control end of the reference circuit, and a signal input end of the test circuit is connected with a signal input end of the reference circuit; the signal processor includes a first input end and a second input end, and the first input end is electrically connected with the signal output end of the photo transistor; and the second input end is electrically connected with the signal output end of the reference transistor.