Diffusive Emissive Display for Pen Input Detection

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Solution Overview

Problem

Existing digital input devices that translate pen motion into digital inputs face limitations with projective capacitive touch sensors, which offer limited functionality and can increase cost and thickness, while electrical sensors can negatively impact the display and product design.

Innovation Solution

The use of diffusive emissive elements arranged in a predetermined pattern on a medium layer that emit light in a diffuse manner in response to non-visible light, allowing for position-encoded input detection without affecting the visible display, using a transparent medium layer with near-IR diffusely emissive patterns that are substantially clear in the visible spectrum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If projective capacitive touch sensors are used for input detection, then input functionality is provided, but device complexity and cost increase

Engineering Contradiction:
Improveinput functionalityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the input detection functionality from complex electronic sensor systems and implements it through a simplified optical encoding approach using diffusive emissive elements arranged in predetermined patterns that can be detected by a camera, thereby reducing device complexity while maintaining input functionality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/electrical sensor system with an optical system that uses light-emitting elements and camera detection, substituting complex electronic sensing mechanisms with a simpler optical field-based detection method

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If electrical sensors are added to the display, then input detection capability is improved, but display thickness and product thickness increase

Engineering Contradiction:
Improveinput detection capabilityVSAvoiddisplay thickness
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The patent substitutes electrical sensors with an optical detection system that uses diffusive emissive elements and camera-based detection, eliminating the need for thick electrical sensor layers and associated electronics, thereby maintaining display thickness

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If electrical sensors are integrated into the display, then input detection is enabled, but system cost increases

Engineering Contradiction:
Improveinput detectionVSAvoidsystem cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent uses inexpensive diffusive emissive elements that can be printed or applied as a layer on the display surface, replacing costly electrical sensor arrays with a low-cost optical encoding solution that achieves the same input detection functionality

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent extracts the sensing function from expensive electrical sensors and implements it through a combination of simple optical elements and existing camera technology, thereby reducing system cost

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If a non-transparent input detection layer is added, then input detection accuracy is improved, but visible display quality deteriorates

Engineering Contradiction:
Improveinput detection accuracyVSAvoidvisible display quality
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The patent applies local quality by making the diffusive emissive elements transparent or translucent in the visible spectrum while maintaining their light-emitting properties in the infrared spectrum, allowing the input detection layer to be both functionally effective and visually transparent

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the optical parameters of the diffusive emissive elements to emit primarily in the infrared spectrum rather than visible light, allowing high-contrast pattern detection for input accuracy while maintaining visual display quality through transparency in the visible range

Inventive Principle:
Principle #35Parameter changes

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 provides a high-fidelity visual display with enhanced input accuracy and image quality, maintaining transparency and reducing system costs by using a low-cost, printable solution that effectively captures position-encoded data from a digital pen, improving signal-to-noise ratio and contrast.

Implementation Method 1

diffusive emissive elements arranged in a predetermined pattern on a medium layer that emit light in a diffuse, or scattered, manner in response to non-visible incident light

Methodology Applied
Scientific EffectDiffuse emission: Scattering

Implementation Method 2

WO2012/102690 discloses a filter which includes a pattern which may reflect or fluoresce non-visible light

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 3

The diffusive emissive elements and the medium layer are substantively optically transparent to visible light generated from the display stack

Methodology Applied
Scientific EffectOptical transparency: Absorption (EM radiation)

Data Source

PatentEP3170064B1A diffusive emissive display
Publication Date: 2019.11.06 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3170064B1 patent drawingFigure 1
  • EP3170064B1 patent drawingFigure 2~3
  • EP3170064B1 patent drawingFigure 4~5

AI summary

A display includes a display stack to generate a digital display image. A media layer includes a plurality of diffusive emissive elements disposed in a predetermined pattern. The diffusive emissive elements on the media layer emit a scattered signal in response to light incident to the media layer.