Capacitive Position Sensing for Sliding Keyboard Virtual Display

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Solution Overview

Problem

Existing small electronic devices, such as handheld wireless communication devices, face challenges in detecting the position of movable assemblies like physical keyboards without using additional electro-mechanical components, which increase cost and consume valuable space.

Innovation Solution

A capacitive touch detection sensor matrix is used in conjunction with a touch controller to detect the position of a physical keyboard, allowing for the display of a virtual keyboard based on the physical keyboard's position, eliminating the need for costly switches and magnets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional electro-mechanical components (switches and magnets) are used to detect the position of the movable assembly, then the position detection reliability is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:

Improveposition detection reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces electro-mechanical components (switches and magnets) with a capacitive sensing system. The capacitive sensor detects changes in capacitance caused by the position of the movable assembly, eliminating the need for mechanical switches and magnetic components. This substitution maintains position detection functionality while reducing device complexity and component count.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The capacitive sensor system utilizes the device's existing touchscreen controller and processing capabilities to perform position detection. The system leverages the inherent capacitive properties of the touchscreen architecture, allowing the device to detect movable assembly position using its own existing infrastructure without requiring separate dedicated detection hardware.

Inventive Principle:

Principle #25Self-service

2Reliability

Engineering Contradiction:

Improveposition detection reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive electro-mechanical components with a capacitive sensing approach that utilizes existing touchscreen infrastructure. This eliminates the need to source, assemble, and test additional mechanical switches and magnetic components, thereby reducing manufacturing costs while maintaining detection reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The capacitive sensor system serves multiple functions: it detects the position of the movable assembly, identifies when keys are pressed, and integrates with the existing touchscreen interface. This multi-functionality eliminates the need for separate dedicated detection components, reducing overall component count and manufacturing complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

Engineering Contradiction:

Improveposition detection reliabilityVSAvoiddevice volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces bulky electro-mechanical components with a capacitive sensing system that uses the existing touchscreen substrate. The capacitive sensors are integrated into the touchscreen layers, requiring minimal additional space and eliminating the need for separate mechanical switches and magnetic components that would increase device volume.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The capacitive sensing elements are nested within the existing touchscreen structure, utilizing the same physical space and infrastructure. The sensors are integrated into the touchscreen controller and display layers, allowing position detection functionality to be embedded within the existing device architecture without requiring additional external components.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 precise detection of the physical keyboard's position, allowing for dynamic display of virtual keyboards that adapt to the physical keyboard's state, enhancing user interaction while reducing device complexity and cost.

Implementation Method 1

A capacitive touch detection sensor matrix is used in conjunction with a touch controller to detect the position of a physical keyboard

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3151088B1Method and apparatus for movable assembly position sensing and virtual keyboard display

Publication Date: 2019.11.06 BLACKBERRY LTD

Figure 1A~1C
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AI summary

A device comprises a housing section comprising a touch-sensitive display; and a physical keyboard section coupled to the housing section such that the physical keyboard is movable in a sliding direction relative to the housing. A position detector determines a position of the physical keyboard section in relation to the housing section; and a processor displays a graphical element on the touch-sensitive display when the position of the physical keyboard is closed and displays no graphical element when the position of the physical keyboard is open.