Optical Dartboard Layout for Triangulating Overlapping Dart Hits

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Solution Overview

Problem

Existing dart game apparatuses struggle to accurately calculate the positions of all thrown darts when they intersect in specific patterns, particularly when only one photo-sensor can detect the shade of a dart, rendering triangulation impossible.

Innovation Solution

The apparatus employs a configuration of n × 2 photo-sensors to ensure all n darts thrown in a round can be calculated by triangulation, utilizing a retro-reflector to enhance light detection and a CPU to process brightness differences for precise positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If five photo-sensors are disposed on a dart board at equal intervals, then the device complexity is reduced, but the measurement precision deteriorates when darts hit specific intersecting positions

Engineering Contradiction:
Improvenumber of photo-sensorsVSAvoiddart position calculation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transitions from using photo-sensors only on the dart board surface to incorporating a retro-reflector behind the dart board, creating a three-dimensional light detection system. This allows light to reflect back through the dart board, enabling photo-sensors to detect darts from both front and back perspectives, thus resolving the measurement precision issue without adding more sensors on the board surface.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The retro-reflector acts as an intermediary element that redirects light back through the dart board. When a dart blocks light, the retro-reflector reflects the light back through the same path, allowing photo-sensors to detect the dart's position from the rear side of the board, effectively doubling the detection capability without increasing the number of photo-sensors.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If n × 2 photo-sensors are used to calculate all n darts positions, then the measurement precision is improved, but the device complexity increases

Engineering Contradiction:
Improvedart position calculation accuracyVSAvoidnumber of photo-sensors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the detection capability of front and back photo-sensors into a unified triangulation system. By merging the information from both sides, the system achieves comprehensive dart position detection for all n darts, ensuring that even when darts hit intersecting positions, at least two sensors can detect each dart for accurate triangulation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses feedback from multiple sensor detections to resolve ambiguous positions. When darts hit positions that might be undetectable by a single sensor, the feedback mechanism allows the system to cross-validate detections from multiple sensors and correctly calculate positions using triangulation, ensuring all dart positions are accurately determined.

Inventive Principle:
Principle #23Feedback

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 approach allows for accurate calculation of all dart positions, minimizing manufacturing costs through optimized sensor usage and reducing positional errors, especially when darts hit close together.

Implementation Method 1

utilizing a retro-reflector to enhance light detection

Methodology Applied
Scientific EffectRetro-reflection: Retroreflector

Implementation Method 2

a position (coordinates) of a dart that hits the dart board is calculated by detecting the interruption of the light emitted from the light-emitting sensors, caused by the dart

Methodology Applied
Scientific EffectLight interruption detection: Photoelectric Effect

Implementation Method 3

Patent Document 2 discloses a technique to calculate a position of a dart by triangulation, based on the brightness of the light (shade of the dart) generated by the dart, out of the brightness of the lights detected by photo-sensors

Methodology Applied
Scientific EffectTriangulation: Parallax

Data Source

PatentEP3663700B1Darts game device
Publication Date: 2026.02.25 SEGA CORP
  • EP3663700B1 patent drawingFigure 1
  • EP3663700B1 patent drawingFigure 2
  • EP3663700B1 patent drawingFigure 3

AI summary

A dart game apparatus that provides a dart game in which one player successively throws n number of (n = 3 or 4) darts D at a dart board 12, having: light sources LS that are disposed around the dart board 12 and emit lights L along the board face of the dart board 12; a plurality of photo-sensors S that are disposed around the dart board 12 at approximately the same height from the dart board 12 in the board thickness direction, and detect the brightness of the lights L emitted from the light sources LS; and a processor that calculates a hit position of a dart D in the dart board 12 based on the brightness of each light. A number of photo-sensors S is n × 2.