Liquid-Filled Bladder Touch Display for Durability and Repair

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Solution Overview

Problem

Existing touch-sensitive displays in portable electronic devices face challenges in optimizing space usage and durability while maintaining effective touch detection and protection from environmental factors, particularly in handheld devices with limited space.

Innovation Solution

A touch-sensitive display design featuring a capacitive touch sensor with a bladder-filled cavity between the sensor and a cover, where a liquid with a suitable dielectric constant is used to facilitate touch detection, allowing for elastic deformation and reducing the need for adhesives, thus enhancing durability and ease of replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid adhesive structure is used to bond the cover to the touch sensor, then structural strength is improved, but durability and ease of replacement deteriorate

Engineering Contradiction:
Improvestructural strengthVSAvoidease of replacement
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The patent employs a bladder filled with liquid (hydraulic element) positioned between the cover and touch sensor. This liquid-filled bladder provides structural support and maintains spacing without requiring permanent adhesive bonding, enabling the cover to be removed and replaced easily while maintaining assembly integrity during use.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The bladder is constructed as a flexible membrane structure that can deform elastically in response to touch inputs and assembly variations. This flexibility allows the bladder to accommodate minor misalignments and maintain contact pressure without rigid bonding, facilitating easy cover replacement while preserving structural function.

Inventive Principle:
Principle #30Flexible shells and thin films

2Volume of moving object

If the cover is placed close to the touch sensor to save space, then space utilization is improved, but protection from environmental factors deteriorates

Engineering Contradiction:
Improvespace utilizationVSAvoidprotection from environmental factors
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The liquid-filled bladder serves as an intermediary element positioned between the cover and touch sensor. It maintains an optimal spacing that provides environmental protection (preventing dust and water ingress) while keeping the overall assembly compact. The bladder's compliance allows it to fill available space efficiently without requiring excessive gaps.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flexible bladder membrane creates a sealed barrier that prevents environmental contaminants from reaching the touch sensor while maintaining a compact profile. Its ability to deform allows it to provide consistent protection across varying assembly conditions without requiring large clearance distances.

Inventive Principle:
Principle #30Flexible shells and thin films

3Stability of the object's composition

If a fixed rigid structure is used between the cover and touch sensor, then structural stability is improved, but adaptability to touch deformation deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidadaptability to touch deformation
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The bladder is designed as a dynamic, compliant element that deforms in response to touch forces applied to the cover. This dynamic behavior allows the structure to adapt to various touch inputs (pressure, location, duration) while maintaining overall assembly stability. The liquid-filled bladder redistributes applied forces uniformly, providing stable feedback to the touch sensor.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The liquid-filled bladder acts as a hydraulic cushion that transmits touch forces from the cover to the touch sensor while accommodating deformation. The incompressible liquid provides stable force transmission, and the bladder's elastic membrane allows controlled deformation that adapts to different touch patterns while maintaining structural integrity.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 design enhances touch detection accuracy, reduces manufacturing costs, and provides improved durability and protection against dust and water ingress, while allowing for easy replacement of the cover without affecting the touch sensor or display.

Implementation Method 1

a liquid with a suitable dielectric constant is used to facilitate touch detection

Methodology Applied
Scientific EffectDielectric: Dielectric

Implementation Method 2

allowing for elastic deformation

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2538312B1Touch-sensitive display and electronic device including same
Publication Date: 2014.10.22 BLACKBERRY LTD
  • EP2538312B1 patent drawingFigure 1
  • EP2538312B1 patent drawingFigure 2~4

AI summary

A touch-sensitive display includes a display, a capacitive touch sensor disposed on the display, a cover spaced from the capacitive touch sensor, and a liquid disposed in a cavity between the capacitive touch sensor and the cover.