External-Electrode UV Lamp Circuit to Prevent Edge Spark Discharge
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Solution Overview
Problem
Existing gas discharge ultraviolet light-emitting devices face issues with expensive quartz glass envelopes, high-voltage power supplies, complex electrode structures, low luminous efficiency, and unwanted spark discharges along the side edges of electrodes, which affect safety and emission intensity.
Innovation Solution
A gas discharge light-emitting device with a pair of long electrodes on the outer surface of a thin glass tube, using an insulating layer between the electrodes and the tube to prevent spark discharges, and a drive circuit with a printed substrate for integrated module construction, ensuring efficient and intense ultraviolet light emission without mercury.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a quartz glass envelope is used for UV-C emission, then ultraviolet light emission is achieved, but the device becomes expensive
Solution Approach 1:
The patent replaces expensive quartz glass envelopes with inexpensive borosilicate glass tubes that can be mass-produced using conventional glassblowing techniques. The glass tube serves as a disposable envelope that contains the discharge gas and enables UV emission without requiring costly quartz materials.
Solution Approach 2:
The patent changes the material parameter from quartz glass to borosilicate glass, and adjusts the discharge gas composition (using xenon and neon mixture at specific ratios) to achieve optimal UV emission at lower costs while maintaining effectiveness.
2Illumination intensity
If a high-voltage rectangular-wave alternating-current power supply is used, then excimer discharge is achieved, but the drive system becomes complex
Solution Approach 1:
The patent changes the drive voltage waveform from rectangular-wave to sine wave, and operates at a lower voltage range (2000-5000V peak) compared to conventional high-voltage systems. This simplifies the power supply requirements while maintaining effective discharge.
Solution Approach 2:
The patent uses sine wave voltage application with specific frequency characteristics to generate periodic discharge along the electrode length, replacing the need for complex rectangular-wave generation circuits.
3Productivity
If electrodes are placed close to the glass tube surface, then discharge efficiency is improved, but spark discharge occurs along the side edges
Solution Approach 1:
The patent introduces an insulating layer as an intermediary substance between the electrode and the glass tube surface. This layer prevents direct contact and eliminates spark discharge along the side edges while maintaining sufficient proximity for efficient discharge through the gas-filled tube.
Solution Approach 2:
The patent segments the electrode structure by separating it from the glass tube surface using an insulating layer, and divides the electrode into multiple sections along the tube length to control discharge distribution and prevent edge sparking.
4Volume of moving object
If a thin glass tube is used, then the device becomes compact, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise parameter ranges for the glass tube (outer diameter 1-5mm, thickness 0.5-2mm) that balance compactness with manufacturability. These parameters enable thin-tube construction while remaining compatible with conventional glassblowing and drawing processes.
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 provides a cost-effective, high-efficiency, and safe ultraviolet light source with uniform emission across the entire length of the tube, preventing spark discharges and allowing for compact, high-intensity ultraviolet radiation suitable for medical and industrial applications.
Implementation Method 1
a gas discharge light-emitting device which has an external electrode structure including a thin glass tube as a main component and which uses a gas discharge
Implementation Method 2
the inside of the tube is substantially in a conductive state due to a plasma throughout the entire length
Implementation Method 3
a phosphor layer which is arranged on the inner surface of the glass tube and has a function of emitting ultraviolet light when vacuum ultraviolet light is applied thereto
Implementation Method 4
an insulating layer which is interposed between the discharge electrodes and the outer surface of the glass tube
Implementation Method 5
the inside of the tube is substantially in a conductive state due to a plasma throughout the entire length
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3
AI summary
The object of the present invention is to provide an ultraviolet light source, which has a simple configuration, is inexpensive, and has excellent luminous efficiency. A gas discharge light-emitting device comprising a glass tube filled with a discharge gas, and at least a pair of electrodes provided on an outer wall surface of the glass tube through an insulating layer so as to extend along a longitudinal direction of the glass tube to be away from each other. An ultraviolet phosphor layer is formed on an inner surface of the glass tube on the bottom part, whereby a high-efficient ultraviolet light-emitting can be obtained. Also, a flat light source for ultraviolet light emission can be obtained by arraying multiple ultraviolet light-emitting tubes parallel to one another.