Transparent Photovoltaic Sensor for Smartcard Energy Harvesting

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Solution Overview

Problem

Conventional multifunction smart cards with photovoltaic sensors have an unattractive appearance that masks visual information and limits the surface area for energy harvesting, reducing the electrical power that can be recovered to supply the energy storage device.

Innovation Solution

A transparent photovoltaic sensor is integrated over at least 70% of the card's surface using an electrically conductive adhesive film or metal particles bonded by a non-conductive paste, allowing the sensor to appear transparent by optical effect while maintaining electrical connectivity for energy harvesting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a photovoltaic sensor is integrated into the smart card to recharge the energy storage device, then the electrical power recovered is improved, but the appearance is degraded and visual information is masked

Engineering Contradiction:
Improveelectrical power recoveredVSAvoidappearance
Core Design Contradiction:
PowerVSShape

Solution Approach 1:

The photovoltaic sensor is designed to be transparent or translucent, changing its optical properties from conventional opaque solar cells. This allows the sensor to maintain its power-generating function while becoming visually imperceptible or blending with the card design, thus resolving the contradiction between power recovery and appearance

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The optical parameters of the photovoltaic sensor are modified to achieve transparency or translucency. By changing the material properties and optical characteristics of the sensor, it can capture light for energy generation while allowing visual information to pass through, thereby improving both appearance and maintaining power recovery capability

Inventive Principle:
Principle #35Parameter changes

2Shape

If the photovoltaic sensor surface area is reduced to improve appearance, then the appearance is improved, but the electrical power recovered is reduced

Engineering Contradiction:
ImproveappearanceVSAvoidelectrical power recovered
Core Design Contradiction:
ShapeVSPower

Solution Approach 1:

By making the photovoltaic sensor transparent or translucent, the entire card surface can be utilized for energy harvesting without compromising appearance. The transparency allows visual information to be displayed while the sensor material continues to absorb light for power generation across the full surface area

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The card surface serves dual functions: it acts as both a display area for visual information and an energy harvesting area for power generation. The transparent photovoltaic sensor enables these two functions to coexist on the same surface, maximizing both appearance quality and power recovery capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Shape

If a transparent photovoltaic sensor is used to improve appearance and maximize surface area, then the visual information visibility is improved, but the electrical connectivity for energy harvesting must be maintained

Engineering Contradiction:
Improvevisual information visibilityVSAvoidelectrical connectivity maintenance
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

Transparent conductive materials serve as intermediaries between the transparent photovoltaic sensor and the underlying circuitry. These materials maintain electrical connectivity while preserving optical transparency, allowing both visual information visibility and energy harvesting to function simultaneously without compromising either aspect

Inventive Principle:
Principle #24Intermediary (Mediator)

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 the appearance of the smart card while maximizing the energy capture surface, allowing for efficient recharging of the energy storage device without obstructing visual information.

Implementation Method 1

a photovoltaic sensor, extending at least partially over one face of the card body element and being electrically connected to the energy storage device to recharge this energy storage device

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

The transparent photovoltaic sensor extends over at least 70% of the surface of the card body element

Methodology Applied
Scientific EffectOptical transparency:

Data Source

PatentEP2936395B1Multifunctional smartcard comprising a photovoltaic sensor
Publication Date: 2021.06.02 THALES DIS FRANCE SA
  • EP2936395B1 patent drawingFigure 1~3
  • EP2936395B1 patent drawingFigure 4~6

AI summary

The invention relates to a chip holder, such as a smartcard (2), comprising: a holding body element, such as a card body (4), comprising a printed circuit board (14) and a photovoltaic sensor (12) that is at least partially transparent to visible light and that extends over at least part of one face of the holding body element and that is electrically connected to the printed circuit board by an electrical connection; and a layer or film of a material that is opaque to visible light, which layer or film is located between the printed circuit board and the photovoltaic sensor (12) and at least partially masks the printed circuit board, characterised in that said electrical connection extends through an aperture in the opaque film or layer.