(Fuzhou Xie Telai Lighting Co., Ltd., Fuzhou 350014)
Abstract: LED refers to light-emitting diodes, LEDs have inorganic light-emitting diodes (ILEDs), organic light-emitting diodes (OLEDs), and ILEDs and OLEDs are collectively referred to as solid-state light-emitting diodes. GLED refers to gas light-emitting diodes with a new wick structure and working mechanism.
Key words positive halo discharge hollow cathode discharge GLED
1 Introduction
People always want to use fluorescent lamps like incandescent lamps. This makes it possible to make straight fluorescent lamps into H, U, spiral and other patterns; on the other hand, small discharge lamps with the appearance of incandescent lamps have been developed.
Fig. 1 shows a small discharge lamp disclosed in Japanese Patent Laid-Open Publication No. SHO-63-234976. The anode and cathode are arranged at close distances and are parallel to each other. The wick will cause a short circuit of the arc and the cathode decomposition is difficult to complete; a uniform electric field is formed in the discharge space, so that the discharge falls into the mode of the positive column discharge, the electrode position drops greatly, and the anode rod is red hot (tube current 300 mA, anode rod) 800 ° C or more). In order to solve the problem of red heat of the anode rod, the patentee took five cooling measures on the anode rod. This makes the structure of the lamp complicated and the cost performance is low.
Similar technical solutions include U.S. Patent No. 3,243,632 and the like.
Figure 2 shows another small-sized discharge lamp that appears on the domestic and international markets, using a V-shaped filament as the electrode. The lighting is achieved by energizing the filament to reach the hot spot operating temperature, and discharges at both ends of the filament to form radiation; obviously, the lamp utilizes the principle of glow decomposition of the cathode. In order to maintain the discharge at both ends, the application of the electronic powder can only be limited to a short range at both ends of the filament, the life of the lamp is about 2000 hours, and the power is difficult to enlarge. In order to meet the needs of the market and enable people to truly obtain incandescent fluorescent lamps, it is necessary to explore new wick structures and working mechanisms.
2 positive halo discharge
The so-called positive halo discharge means that the cathode and the anode are not arranged in parallel, and the non-uniform electric field is distributed between the electrodes, and the ratio of the effective radius of the cathode to the effective radius of the anode is greater than the natural constant e. This kind of discharge will produce an anode corona near the anode. The main part of the discharge is the anode corona layer. The anode rod only acts as a conduction current, which effectively alleviates the red heat problem of the anode rod; the anode corona of this discharge The thickness of the layer is proportional to the discharge current, the discharge exhibits a positive resistance characteristic, and the discharge is stable.
3 hollow cathode discharge
If the cathode is formed into a pattern having a cavity structure in which the anode resides in the center of the cathode cavity, such discharge has the characteristics of a hollow cathode discharge. After the electrons emerge from the hot spot, the velocity direction of most electrons does not point to the anode due to the non-uniform electric field. They will follow the parabolic orbital: the electric field is accelerated in the space toward the anode, and the electric field is decelerated in the space away from the anode. As a result, the anode will reciprocate around the anode, which will lead to an increase in the number of collisions of electrons with the working gas, and the effect of excitation and ionization is greatly enhanced. This discharge has a very low electrode drop and a large discharge current density.
4 GLED
A gas light emitting diode, GLED, is a new type of discharge lamp that combines positive and negative cathode discharges. 3, 4, 5, and 6 are schematic views of a part of the GLED developed so far. The common feature is that the cathode has a cavity structure, the anode rod is located in the center of the cathode cavity, and the non-uniform electric field is distributed between the cathode and the anode, and the ratio of the effective radius of the cathode to the effective radius of the anode is greater than the natural constant e. The cathode and the anode in the bulb are electrically connected by the guide wire and the external power source: the outer portion of the two guide wires supporting the spiral of the cathode filament is connected to the negative pole of the power source; the outer portion of the anode rod guide wire and the power source Positive connection. The glass bulb is made of a transparent purple material and is an ultraviolet lamp; the inner wall of the glass bulb is coated with a phosphor to form a fluorescent lamp.
5 lighting effects
5.1 positive resistance discharge
There are many forms of discharge. The prior art commonly used is a positive column discharge; the positive column discharge is based on a parallel electrode and a uniform electric field, showing a negative resistance characteristic. The discharge with positive resistance is a positive halo discharge. It is based on a non-parallel electrode and a non-uniform electric field. The ratio of the effective radius of the cathode to the effective radius of the anode must be greater than the natural constant e.
The GLED electrode satisfies the condition of positive halo discharge, the positive to negative electrode has a radial non-uniform electric enthalpy, the positive electrode corona is generated around the anode rod, the positive discharge is mainly involved in the discharge, and the anode rod only acts as a conduction current. The phenomenon that the anode rod is red hot is greatly alleviated; the thickness of the positive corona is proportional to the intensity of the ionization, and the discharge has a positive resistance characteristic. The arc balance resistor is not required in the GLED lighting, and only the capacitor ballast is used, the discharge lamp works stably, and the energy efficiency is high.
5.2 AC lighting
Gas discharges are suitable for operation in an ideal AC state, which prevents rectification effects and mercury trapping; hollow cathode discharges meet this requirement.
The anode rod of the GLED and the filament spiral and the cathode guide wire form a hollow cathode discharge system. After the electrons emerge from the hot spot, the direction of the velocity of most electrons does not point to the anode rod due to the non-uniform electric field. They will follow the parabolic orbit: the space toward the anode rod is accelerated by the electric raft, and the anode rod is away from the anode rod. The space is decelerated by the electric cymbal, and as a result, it will oscillate back and forth around the anode rod. This achieves the potential effect of DC power supply communication without rectification effects and mercury swimming.
5.3 high efficiency and high performance
GLED uses two modes of positive and negative discharge, which are different from the positive column discharge. First, a series of bright and dark areas unique to the positive column discharge are gone. Instead, it is an integrated arc discharge; There is a process of hollow cathode discharge, which can have a high discharge current density and a very low electrode drop. Increasing the lamp current of the discharge lamp results in a higher radiation output. This creates an irreplaceable condition for improving light efficiency and increasing power.
5.4 constant pressure work
Since the outer portions of the two guide wires supporting the spiral of the cathode filament are phased together, the potentials of the cathode spirals are substantially equal, and two or more hot spots may appear in the lighting, and the zero-emission current of the cathode is large. When the working current of the lamp is less than 80% of the zero-field emission current of the cathode, the lamp works stably and reliably, and the tube pressure of the lamp is substantially constant, and the lamp power changes synchronously with the tube flow; GLED achieves the purpose of constant pressure work.
5.5 closed electric field
The discharge interval of the GLED is enclosed between the anode rod and the cathode spiral. The 253.7 nm radiation photons generated by the excitation of the mercury discharge are not charged, and are not affected by the electric field between the electrodes and the poles. They will fully act on the tube wall to complete the ultraviolet emission. Or the function of stimulating the luminescence of the phosphor. The damage of the bulb or phosphor by the interelectrode discharge is the lowest among the discharge lamps with electrodes due to the electric enthalpy closure.
5.6 Instant start
The double-cathode lamp with positive column discharge should not be “slightly bright”. To start instantaneously, a starting electrode must be placed in the lamp. The anode rod of the GLED acts as a good starting electrode and can illuminate the lamp in a quarter of a second. The starting damage is very small and very light. Since no preheating is required, the filament is not heated in the lighting, which reduces many reactive losses. For ultraviolet germicidal lamps, ultraviolet rays are killing bacteria, visible light and infrared rays are used to culture bacteria, and heat radiation in the germicidal lamp is reduced. Improve the sterilization effect of ultraviolet rays.
5.7 lights longevity
GLED has an irreversible DC current for positive ions. When the emitting material leaves the cathode, it is ionized into positive ions, and will return to the cathode under the action of the electric sputum directed to the cathode. (In the case where the cathode zero 埸 emission current is sufficiently large, about 85% to 90% of the thermally evaporating emission material Returning to the cathode), this greatly reduces the rate of consumption of the emissive material. Therefore, the life of GLED is expected to be between ordinary fluorescent lamps and electrodeless lamps.
5.8 ideal light source
GLED protects the appearance characteristics of incandescent lamps. The lamp adopts novel positive halo discharge and hollow cathode discharge working mechanism, which is convenient for people to use and meet energy conservation and environmental protection. It is obviously an ideal light source to meet market demand.
6 outlook
In the evolution process of the light source: the incandescent lamp is a solid AC lighting, the fluorescent lamp is a gas AC lighting; the LED is a solid DC lighting, and the GLED is a gas DC lighting. If the luminous efficacy of the LED is 0.2Lm/w at the initial stage of development, and the working mechanism is basically unchanged, after the efforts of the people, it is said that it has reached 102Lm/w; then, the research and development prospect of GLED is equally encouraging!
References GLED-T Utility Model 2004200581783 GLED-H Utility Model 2006201215302
GLED-Q invention patent 2006101066529 GLED-F utility model 2006200026939
