Integrated Touch Sensing Units in Liquid Crystal Displays

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Solution Overview

Problem

Integrating a touch screen panel with a liquid crystal display increases costs, decreases luminance, and thickens the product, while existing methods for detecting touch positions require significant processing time, especially when multiple touches occur simultaneously.

Innovation Solution

A method and device for a liquid crystal display that includes sensing units connected to sense data lines to read sense signals, determine touch existence and position, and generate X-axis and Y-axis position data, allowing for efficient detection of multiple touches and their sequences without the need for extensive processing time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a touch screen panel is bonded to the liquid crystal display, then touch functionality is achieved, but cost increases, luminance decreases, and product thickness increases

Engineering Contradiction:

Improvetouch functionalityVSAvoidcost

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the touch sensing function with the liquid crystal display by integrating sensing units directly into the display structure. The sensing units are formed within the liquid crystal panel itself, combining the display and touch detection functions into a single integrated device, eliminating the need for separate touch screen panels.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The liquid crystal display is designed to perform multiple functions: displaying images and detecting touch inputs. The sensing units embedded in the display enable the same device to function both as a visual output device and as a touch input device, achieving multi-functionality without adding separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a touch screen panel is bonded to the liquid crystal display, then touch functionality is achieved, but luminance decreases

Engineering Contradiction:

Improvetouch functionalityVSAvoidluminance

Core Design Contradiction:

Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The sensing units are integrated within the liquid crystal panel structure, merging touch detection with the display layers. This integration eliminates the need for additional bonding layers that would block light, thereby maintaining high luminance while achieving touch functionality.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If a touch screen panel is bonded to the liquid crystal display, then touch functionality is achieved, but product thickness increases

Engineering Contradiction:

Improvetouch functionalityVSAvoidproduct thickness

Core Design Contradiction:

Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The sensing units are formed within the existing liquid crystal panel thickness rather than adding separate touch screen layers. By integrating the touch detection function into the display structure itself, the overall product thickness is minimized while still providing touch functionality.

Inventive Principle:

Principle #5Merging (Combining)

4Measurement precision

If sensing units are arranged in row and column directions for touch detection, then touch position can be detected, but processing time increases significantly when multiple touches occur

Engineering Contradiction:

Improvetouch position detectionVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The touch detection process is segmented into distinct phases: a sensing period where sense signals are accumulated from multiple sensing units, and a determination period where the accumulated signals are processed to identify touch positions. This segmentation allows parallel accumulation of data followed by efficient batch processing, reducing overall processing time for multiple touches.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Sense signals from multiple sensing units are accumulated in advance during the sensing period before determination is made. This preliminary accumulation of data allows the determination phase to process all touch information simultaneously rather than sequentially, significantly reducing processing time when multiple touches occur.

Inventive Principle:

Principle #10Preliminary action

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

Enables accurate and efficient detection of touch positions with reduced processing time and without the drawbacks of increased cost or luminance loss, by utilizing sensing units and data lines to generate position data directly from sense signals.

Implementation Method 1

The sensing units are arranged in a row direction and a column direction, and when the touch occurs, a sensing unit of the corresponding position outputs a sense signal

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS8736556B2Display device and method of driving the same

Publication Date: 2014.05.27 SAMSUNG DISPLAY CO LTD

AI summary

A method of driving a display device having a plurality of pixels, a plurality of sensing units, and a plurality of sense data lines to which the plurality of sensing units are connected, includes: reading sense signals from the sense data lines; determining whether or not the display has been touched and the number of touches, generating X-axis and Y-axis position data based on the sense signals, and determining, when the quantity of touches is plural, whether a plurality of touches are sequentially generated, and the touch position of each.