Telecentric Lens Coin Sensor for Dust-Resistant Valuation
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Solution Overview
Problem
Existing coin handling equipment struggles with accurate coin discrimination, particularly with Euro coins and high manufacturing costs, and requires improved maintenance and accuracy to handle diverse coin sets and prevent dust interference.
Innovation Solution
A coin sensor system using a telecentric lens and reflective principle for optical detection, combined with inductive and Hall effect sensors, to accurately identify coin size and magnetic properties, with a dust prevention system that includes fan-assisted cleaning and conductive coatings to maintain efficiency and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hybrid sensor with both optical and inductive sensors is used for coin discrimination, then coin discrimination capability is improved, but manufacturing cost increases and dust accumulation interferes with operation
Solution Approach 1:
The patent extracts and removes the inductive sensor component from the hybrid sensor system, retaining only the optical sensor. This eliminates the dust accumulation problem that affected inductive sensors while maintaining coin discrimination capability through optimized optical measurement of coin features such as diameter, thickness, and edge patterns.
Solution Approach 2:
The patent uses optical copying and imaging techniques to capture coin features without physical contact. A camera or optical sensor creates an image copy of the coin, which is then analyzed to determine coin denomination and authenticity, replacing the need for physical inductive sensing.
2Measurement precision
If repeated measurements of coin dimensions are performed as coins pass through the detection station, then measurement precision is improved, but processing time increases
Solution Approach 1:
The patent performs preliminary alignment and positioning of coins before measurement using guide rails and positioning mechanisms. Coins are pre-aligned in a standardized orientation and position, so that when they pass the optical sensor, the measurement can be completed in a single pass without requiring multiple repeated measurements, thus reducing processing time while maintaining accuracy.
Solution Approach 2:
The patent replaces mechanical repeated measurement systems with a high-speed optical imaging system that captures all necessary coin dimensions simultaneously in a single frame. The optical system measures diameter, thickness, and edge patterns concurrently rather than through sequential mechanical probing, dramatically reducing measurement time.
3Device complexity
If the optical sensor operates without dust prevention measures, then device complexity is reduced, but measurement precision deteriorates due to dust interference
Solution Approach 1:
The patent implements a self-cleaning mechanism where a stream of air or gas automatically blows dust particles away from the optical sensor window during coin processing. This self-service dust prevention method maintains measurement precision without requiring manual intervention or complex additional cleaning systems, achieving a balance between simplicity and accuracy.
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 system achieves high-speed coin counting and valuation up to 4500 coins per minute with reduced maintenance needs and improved accuracy, effectively handling diverse coin sets while minimizing dust interference.
Implementation Method 1
a telecentric lens positioned between the optical detector and the coin track, such that the portion of each coin passing the coin sensor is seen to have an apparent size and configuration independent of a variation in distance of the coin from the telecentric lens
Implementation Method 2
a reflector positioned above an inside edge of the coin track and configured to reflect light from the illumination source to the optical detector
Implementation Method 3
combined with inductive and Hall effect sensors, to accurately identify coin size and magnetic properties
Implementation Method 4
combined with inductive and Hall effect sensors, to accurately identify coin size and magnetic properties
Data Source
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AI summary
A coin sensor and method of identifying coins by size and also discriminating invalid coins includes a portion of a coin track (63) over which coins (14) pass in a single file, an illumination source (92) for illuminating at least portions of the coins (14) as the coins move along the coin track (63), an optical detector (95) spaced from the coin track (63) for detecting a size of at least a portion of each coin passing the coin sensor along the coin track, and a telecentric lens (94) positioned between the optical detector (95) and the coin track (63), such that the portion of each coin passing the optical detector (95) is seen to have an apparent size and configuration independent of a variation in distance of the coin from the telecentric lens (94) as each coin moves along the coin track (63). The optical sensor and detector (90) can be angled to assist in preventing stray light from the bottom of the coins from being transmitted to the detector (95). The sensor assembly (67) also includes inductive sensors (98, 99) and a Hall effect sensor (97) for discriminating invalid coins.