Force Sensor Placement at Display Panel Nodal Points

Solution Overview

Problem

Display devices equipped with force sensors face interference from vibrations generated by haptic actuators, leading to inaccurate force detection.

Innovation Solution

The force sensors are strategically positioned at nodal points on the display panel, minimizing the impact of vibrations from the actuator by selecting specific frequencies and disposing sensors at locations where vibrations are minimal, allowing for accurate force sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a force sensor is provided in the display device to detect touch force, then the accuracy of force detection is improved, but the force sensor is affected by vibration generated by the haptic function, causing incorrect operation

Engineering Contradiction:

Improveforce detection accuracyVSAvoidvibration noise from actuator

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The force sensor is specifically positioned at nodal points of the display panel where vibration amplitude is minimal. This localized placement strategy exploits the spatial variation in vibration characteristics across the panel surface, creating a region with reduced vibration noise while maintaining force detection capability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes the natural vibration characteristics of the display panel, specifically identifying and exploiting nodal points where vibration occurs. By positioning the force sensor at these predetermined locations, the system leverages the panel's inherent vibrational mode shapes to minimize interference.

Inventive Principle:

Principle #18Mechanical vibration

2Adaptability or versatility

If the haptic function is added to improve user interaction, then the user experience is enhanced, but the vibration generated interferes with the force sensor operation

Engineering Contradiction:

Improvehaptic function capabilityVSAvoidforce sensor operation reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The force sensor is specifically positioned at nodal points of the display panel where vibration amplitude is minimal. This localized placement strategy exploits the spatial variation in vibration characteristics across the panel surface, creating a region with reduced vibration noise while maintaining force detection capability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The display panel itself acts as an intermediary structure that transmits both haptic vibrations and touch forces. By strategically positioning the force sensor at nodal points on this intermediary structure, the patent allows the panel to fulfill both haptic feedback and force sensing functions simultaneously with minimal mutual interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If multiple force sensors are disposed on the display panel to improve detection coverage, then the detection capability is enhanced, but the complexity of sensor arrangement increases

Engineering Contradiction:

Improveforce detection coverageVSAvoidsensor arrangement complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The force sensor is specifically positioned at nodal points of the display panel where vibration amplitude is minimal. This localized placement strategy exploits the spatial variation in vibration characteristics across the panel surface, creating a region with reduced vibration noise while maintaining force detection capability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The nodal points of the display panel serve multiple purposes: they are both the optimal locations for haptic feedback actuation and the ideal positions for force sensor placement. This universal positioning strategy allows the same structural features to support both haptic and sensing functions, simplifying the overall system design.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enables force sensors to operate effectively despite haptic vibrations, ensuring accurate detection of touch forces and reducing interference from actuator-generated noise.

Implementation Method 1

transferring a vibration corresponding to the selected mode and frequency to a display panel identifying positions of a plurality of nodal points in the display panel, the plurality of nodal points having minimal vibration relative to other points of the display panel responsive to the transferred vibration

Methodology Applied

Scientific EffectVibration: Vibration

Implementation Method 2

a force sensor configured to sense force applied onto the display panel

Methodology Applied

Scientific EffectForce sensing:

Data Source

PatentUS10884501B2Display device including force sensor and method of manufacturing same

Publication Date: 2021.01.05 LG DISPLAY CO LTD

AI summary

The present embodiments provide a display device including a display panel; an actuator configured to generate a predetermined vibration that is applied to the display panel; and a force sensor configured to sense force applied onto the display panel, the force sensor disposed on the display panel at a nodal point of the display panel that minimizes a portion of the sensed force resulting from the predetermined vibration generated by the actuator, and a method for manufacturing the same.