Dual-Function Solar Cell Layout for Compact Light-Emitting Timepieces

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Solution Overview

Problem

Existing electronic timepieces face challenges in achieving both effective power generation and miniaturization due to the need for both a solar cell and a light emitter, which require significant mounting space.

Innovation Solution

Incorporating a solar cell with a compound semiconductor material that emits light when a voltage is applied, allowing the solar cell to function as both a power generator and a light emitter, reducing the overall size and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If both a solar cell and a light emitter are mounted in the electronic timepiece, then power generation and light emission functions are achieved, but the device size increases and miniaturization becomes difficult

Engineering Contradiction:
Improvefunctional integrationVSAvoiddevice size
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent merges the solar cell and light emitter into a single integrated component. The solar cell includes a compound semiconductor layer that can emit light when voltage is applied, eliminating the need for a separate light emitter. This combining of functions into one component directly resolves the contradiction by maintaining both power generation and light emission capabilities while reducing overall device volume.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The solar cell is designed to perform multiple functions: it generates electricity from light during the day and emits light during the night when voltage is applied. This multi-functionality allows a single component to replace what would traditionally require two separate components, thereby achieving miniaturization while maintaining versatility.

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

2Illumination intensity

If a separate light emitter is added to the solar cell assembly, then light emission capability is improved, but mounting space requirements increase

Engineering Contradiction:
Improvelight emission capabilityVSAvoidmounting space
Core Design Contradiction:
Illumination intensityVSArea of stationary object

Solution Approach 1:

The light emitter functionality is merged into the solar cell structure itself. The compound semiconductor layer in the solar cell can emit light when voltage is applied, eliminating the need for a separate light emitter component. This integration maintains light emission capability while significantly reducing the mounting space required.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If multiple components (solar cell and light emitter) are used, then functional completeness is achieved, but device complexity increases

Engineering Contradiction:
Improvefunctional completenessVSAvoidcomponent count
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple components into a single integrated solar cell structure. The solar cell includes electrodes, a compound semiconductor layer, and can perform both power generation and light emission functions. This reduction in component count directly lowers device complexity while maintaining functional completeness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The solar cell is designed as a universal component that can perform both power generation and light emission functions. This multi-functionality eliminates the need for separate dedicated components, thereby reducing device complexity while ensuring all necessary functions are present.

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

The solution enables efficient electricity generation and light emission while minimizing the device's size, enhancing usability and design flexibility.

Implementation Method 1

an active layer that is sandwiched between the pair of electrodes and that includes a compound semiconductor material, the compound semiconductor material being capable of emitting light when a voltage is applied to the pair of electrodes

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

A known electronic timepiece is powered by electricity generated by a solar cell. The solar cell can efficiently generate electricity and charge a secondary battery when the electronic timepiece is used in the daytime or under indoor lighting.

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP4692959A1Electronic timepiece
Publication Date: 2026.02.11 CASIO COMPUTER CO LTD
  • EP4692959A1 patent drawingFigure 1
  • EP4692959A1 patent drawingFigure 2A~2B
  • EP4692959A1 patent drawingFigure 3A~3C

AI summary

Provided is an electronic timepiece capable of achieving both miniaturization and effective power generation and light emission. An electronic timepiece comprising a solar cell (70) having a wiring electrode (71) and a lower electrode (73), which are a pair of electrodes, and a power generation layer (72) that is sandwiched between the pair of electrodes and contains a compound semiconductor material capable of emitting light when a voltage is applied to the pair of electrodes. The electronic timepiece may comprise a plurality of solar cells (70), and the plurality of solar cells may be connected in series. Each wiring electrode (71) on the light incidence side of the pair of electrodes may have an equal contact area with the power generation layer (72).