Light-Shielding Body for Photodetector External Light Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional paper sheet handling apparatuses are prone to photodetector malfunction due to external light, particularly sunlight, which can cause the shutter to close incorrectly.
Innovation Solution
A paper sheet handling apparatus featuring a projector that emits light within the handling port, a photodetector to receive this light, and a light-shielding body along the optical path from the projector to the photodetector, with the projector-side end of the light-shielding body designed to prevent external light from entering, and optionally with grooves or a light-shielding member to further attenuate external light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional light-shielding barrel is connected to the photodetector, then the photodetector is protected against external light, but the photodetector may still malfunction when external light reaches the deepest part of the money deposit/withdrawal port
Solution Approach 1:
The light-shielding body is designed with an asymmetric structure where the projector-side end is retracted from the incident direction of external light towards the photodetector. This creates a multi-dimensional shielding approach: the light-shielding body extends along the optical path from projector to photodetector (one dimension) while the retracted end blocks external light from the money deposit/withdrawal port direction (another dimension), forming a comprehensive light-shielding barrier that prevents external light from reaching the photodetector regardless of its intensity or direction
Solution Approach 2:
The light-shielding body serves as an intermediary element positioned between the external environment (money deposit/withdrawal port) and the photodetector. By placing this light-shielding body along the optical path, it mediates the interaction between external light and the photodetector, blocking harmful external light while allowing the optical detection function to operate reliably
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
Effectively prevents photodetector malfunction caused by external light, ensuring accurate operation of the shutter and reliable handling of paper sheets.
Implementation Method 1
a projector for emitting light within the paper sheet handling port
Implementation Method 2
a photodetector for receiving the light emitted from the projector
Implementation Method 3
a light-shielding body that is formed along an optical path from the projector towards the photodetector and shields the photodetector against external light
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A paper sheet handling apparatus capable of effectively preventing a photodetector from malfunctioning due to external light (600) is provided. The present invention is a paper sheet handling apparatus including a paper sheet handling port, a projector (217) for emitting light within the paper sheet handling port, a photodetector (218) for receiving the light emitted from the projector (217), and a light-shielding body that is formed along an optical path from the projector (217) towards the photodetector (218) and shields the photodetector (218) against external light (600); wherein a projector-side end of the light-shielding body is formed to be retracted from an incident direction of the external light (600) towards the photodetector (218).