Liquid Crystal Display Peripheral Sensor Touch Detection
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Solution Overview
Problem
Conventional liquid crystal displays with touch functions suffer from reduced transmittance, reflectance, or contrast ratio, leading to a compromised display effect, and require complex structures and external encoders for position detection, which increases cost and susceptibility to noise.
Innovation Solution
A liquid crystal display design featuring sensors disposed at the peripheral portions of two substrates, which detect changes in relative positions via electrostatic capacitance variations, allowing for touch position determination without compromising the display effect by not placing sensors on the display surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If photo sensor array is used within each pixel to detect touch position, then touch function is achieved, but transmittance, reflectance, or contrast ratio is reduced
Solution Approach 1:
The touch detection function is segmented from the display area. Sensors are placed only at peripheral portions of the substrates rather than within each pixel, separating the touch detection function from the image display function. This allows the display area to maintain full optical performance while peripheral sensors provide touch detection capability.
Solution Approach 2:
The sensor placement moves from a two-dimensional grid within the pixel matrix to a one-dimensional arrangement along the peripheral edges of the substrates. This dimensional change reduces the number of sensors needed while maintaining touch detection capability, thereby preserving display quality.
2Adaptability or versatility
If photo sensor array is used to detect touch position, then touch function is achieved, but external encoder is required which increases cost and structure complexity
Solution Approach 1:
The liquid crystal display itself serves the dual function of both display and touch detection. The sensors integrated at the periphery of the existing substrates allow the display to detect touch positions without requiring separate external encoder systems, reducing overall system complexity and cost.
3Device complexity
If sensors are disposed at peripheral portions of substrates, then touch position detection is achieved with simplified structure, but display surface area is reduced
Solution Approach 1:
Different portions of the substrate serve different functions: the central display area maintains full optical quality for image presentation, while the peripheral portions are allocated for sensor placement. This local differentiation allows touch detection functionality without significantly compromising the overall display surface area.
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 solution enables accurate touch position detection with a simplified structure that maintains the display quality of the liquid crystal display, reducing costs and noise susceptibility.
Implementation Method 1
The position detection device detects variations of the electrostatic capacitance between the first and the second electrodes when the relative position between the first and the second substrates is changed
Data Source
AI summary
A liquid crystal display including a first substrate, a second substrate, a plurality of sensors, and a position detection device is disclosed. The first substrate includes a plurality of pixel electrodes. The second substrate includes at least one opposite electrode and passed through by light. A liquid crystal component is enclosed between the first and the second substrates, and a voltage between the first and the second substrates is controlled to display an image. The sensors are disposed on peripheral portions of the first and the second substrates and output signals corresponding to relative positions of the first and the second substrates. The position detection device receives the signals output from the sensors to determine a touched position on the glass substrate.