Integrated Touch Sensing LCD with Segmented Display Areas
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Solution Overview
Problem
Conventional touch detecting liquid crystal displays (LCDs) face challenges such as increased thickness and weight due to external photosensors, interference between display and sensing signals, and sensitivity to environmental luminance, which affects touch detection accuracy and pixel resolution.
Innovation Solution
A display device with separate primary and secondary display areas, where the secondary area incorporates touch sensing circuits with photo sensing elements and higher resolution than the primary display area, allowing independent operation of display and sensing functions without interfering with each other, and using a flexible printed circuit for electrical connection between the panels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If photosensors are provided on an external device such as a touch screen panel to be attached to the LCD, then touch sensing function is achieved, but the thickness and weight of the LCD increase
Solution Approach 1:
The patent merges the touch sensing function with the LCD display by integrating photosensors directly into the LCD structure. The photosensors are incorporated into the pixel structure itself, allowing the display panel to perform both display and touch sensing functions simultaneously, thereby eliminating the need for separate external sensing components and reducing overall weight.
2Adaptability or versatility
If photosensors are provided on an external device such as a touch screen panel to be attached to the LCD, then touch sensing function is achieved, but it becomes difficult to represent minute characters or pictures
Solution Approach 1:
The patent segments the display area into multiple pixels, with each pixel containing both display elements and integrated photosensors. This segmentation allows the sensing function to be distributed across the entire display area at the pixel level, maintaining high spatial resolution for detecting minute touches while preserving the ability to display fine characters and pictures.
3Adaptability or versatility
If a photosensor is incorporated into an LCD as a TFT disposed in a pixel displaying an image, then touch sensing is enabled, but display signals and sensing signals interfere with each other
Solution Approach 1:
The patent employs periodic action by sequentially operating display and sensing functions in different time periods. During certain time intervals, the display function is activated while sensing is disabled, and during other intervals, sensing is performed while display is temporarily suspended or maintained at a stable state. This time-division multiplexing approach prevents signal interference between display and sensing operations.
4Adaptability or versatility
If photosensors are incorporated into the display area, then touch sensing function is achieved, but the resolution of the pixels decreases
Solution Approach 1:
The patent makes the pixel structure universal by designing it to perform multiple functions simultaneously - both display and touch sensing. Each pixel is equipped with both display elements (such as liquid crystal cells or OLED structures) and photosensors, allowing the same physical space to serve dual purposes. This multi-functionality approach maintains pixel resolution while enabling touch sensing without requiring separate dedicated sensing pixels.
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 touch detection accuracy by reducing signal interference and environmental sensitivity, while maintaining high pixel resolution in the primary display area, and allows for effective determination of touch information without additional sensing circuits for physical quantities.
Implementation Method 1
Each of the sensing circuits may form a pixel along with one of the second display circuits... touch sensing circuits disposed in the second display area... photo sensing circuits generating sensor output signals based on an amount of ambient light
Data Source
AI summary
A display device according to an embodiment of the present invention includes a display panel having a first display area and a second display area. The display panel includes: a plurality of first display circuits disposed in the first display area; a plurality of second display circuits disposed in the second display area; and a plurality of touch sensing circuits disposed in the second display area.