WO2001027522A1

WO2001027522A1 - Dc fluorescent lamp without stroboscopic effect

Info

Publication number: WO2001027522A1
Application number: PCT/CN1999/000159
Authority: WO
Inventors: Zhenping Lu; Qianhong Wu
Original assignee: Zhenping Lu; Qianhong Wu
Priority date: 1999-10-10
Filing date: 1999-10-10
Publication date: 2001-04-19
Also published as: CN1328627A; AU6076499A; CN1101532C

Abstract

The invention relates a DC fluorescent lamp without stroboscopic effect. The DC fluorescent lamp comprises a DC fluorescent tube, a DC electronic ballast and a lamp hanger. In the tube, electron powder is applied only on the filament of negative electrode and no electron powder on the filament of positive electrode. The filament of positive electrode is thicker than one of negative electrode. In the DC electronic ballast, the preheating circuit for the filament preferably is a relay-type preheating circuit. The main advantage of the invention is well to solve following problems about a dark region and blackening of the filament of positive electrode, and to prolong lifetime of the fluorescent tube. The invention also makes the DC fluorescent tube to be start once successfully, increasing lifetime of the fluorescent tube and being favorable to protect human eyes.

Description

TECHNICAL FIELD The present invention relates to a lamp, and is a flicker-free DC fluorescent lamp. BACKGROUND OF THE INVENTION There are currently two types of Pu'er fluorescent lamps: inductive ballast fluorescent lamps and electronic ballast fluorescent lamps. Inductive ballast fluorescent lamps use 50 HZ (or 60 HZ) alternating current, so the flicker phenomenon is serious, which affects people's vision greatly, and the eyes are easily fatigued. Reading in this kind of light can easily hurt the eyes. In the early 1980s, the Dutch Philips company first developed an electronic ballast capable of operating at a high frequency (30-60 KHZ). Because of its high luminous efficiency, it can start at low voltage, so As soon as it appeared, it attracted people's attention, hoping to use it to replace the original inductive ballast. But in fact, it does not completely eliminate the flicker, but only modulates it into high frequency under the frequency of the electric power source. It has both a low frequency strobe of 50 Hz and a high frequency strobe of 30-60 KHZ. The influence of force is smaller. Chinese Patent Gazette has published a number of patents for electronic ballasts for fluorescent lamps. Among them, the "No-flicker energy-saving fluorescent lamp device" with patent number ZL 93112478. 6 mainly discloses a DC electronic ballast, which solves the problem well. Because of the strobe problem, the power saving effect is also obvious. The flicker-free energy-saving fluorescent lamp device includes a fluorescent lamp tube, a DC electronic ballast, and a lamp stand. Among them, the DC electronic ballast mainly includes a high-voltage start-up circuit, a step-down circuit, and a bridge rectifier. Filter circuit, a transistor current stabilization circuit, and a filament preheating circuit; the high-voltage starter circuit and the bridge rectifier filter circuit have an indirect isolation diode, the step-down circuit and the bridge rectifier filter circuit are connected in series, and then connected in parallel with the high-voltage starter circuit. At both ends of the AC power source, the transistor current stabilizing circuit is connected in series with an isolation diode and a bridge rectifier filter circuit, and then is connected to the positive end of the fluorescent tube, and the negative end of the fluorescent tube. Connect the anode of the bridge rectifier filter circuit, the other end of the anode of the fluorescent tube is connected to the filament preheat circuit composed of the filament preheating bubble and the resistor in series, and the other end of the filament preheat circuit is connected to the anode of the bridge rectifier filter circuit capacitor. It can be seen that this patent has not yet explicitly dealt with fluorescent lamp tubes. Practice has proved that if a DC electronic ballast is equipped with a common AC fluorescent lamp, after the lamp is exposed to DC for a period of time, the dark area of the positive electrode and the early blackening of the positive electrode will occur, affecting the luminous efficiency of the lamp and the life of the lamp. SUMMARY OF THE INVENTION The object of the present invention is to provide a flicker-free DC fluorescent lamp that matches an electronic ballast with a fluorescent tube, so that the fluorescent tube can both obtain a stable DC power supply, solve the flicker problem of the fluorescent lamp, and avoid the positive electrode of the tube. Early blackening due to electron bombardment improves the luminous efficiency of the lamp and prolongs the service life of the lamp.

The invention for achieving the above-mentioned object includes three parts: a fluorescent tube, a DC electronic ballast and a lamp holder; the DC electronic ballast includes a high-voltage start-up circuit, a step-down circuit, a bridge rectifier filter circuit, and a transistor. The current stabilizing circuit and a filament preheating circuit may also include a protection circuit; the high-voltage starter circuit and the bridge rectifier filter circuit have an indirect isolation diode, the step-down circuit and the bridge rectifier filter circuit are connected in series, and then connected in parallel with the high-voltage starter circuit. Connected to both ends of the AC power supply, the transistor current stabilizing circuit is connected in series with the isolation diode and the bridge rectifier filter circuit and then connected to the positive electrode of the fluorescent tube. (If a protection circuit is also used, connect the transistor current stabilizing circuit and the protection circuit in series and then connect the fluorescent tube. Positive electrode, the protection circuit mainly protects the transistor in the transistor current stabilization circuit from burning out), one end of the negative electrode of the fluorescent tube is connected to the negative electrode of the bridge flow filter circuit, the other end of the negative electrode of the fluorescent tube is connected to the filament preheating circuit, and the filament is preheated The other end of the circuit is connected to the positive terminal of the bridge rectifier filter circuit capacitor. A feature of the present invention is that a fluorescent tube is a direct current fluorescent tube. The negative electrode filament of the direct current fluorescent tube is coated with electronic powder, and the positive electrode filament is not coated with electronic powder and is slightly thicker than the negative electrode.

The existing filament preheating circuit consisting of a filament preheating bubble and a resistor requires one side Fluorescent lamps can be successfully ignited multiple times before they are ignited. Therefore, fluorescent lamps are subject to the impact of multiple priming currents, which affects the lamp life. To this end, the present invention proposes a relay filament preheating circuit, which mainly includes a relay J, a transistor triode V2, a bridge rectifier circuit D6, a voltage regulator Wl, electrolytic capacitors C8, C9, and a resistor. R 6, 9; the collector of the transistor triode V 2 is connected to the anode of the bridge rectifier circuit D 6, the emitter is connected to one end of the relay J coil, and the relay wire 圏; the other end of Γ is connected to the anode of the bridge rectifier circuit D 6, the crystal The base of the transistor V 2 is connected to the positive electrode of the resistor R 9 and the electrolytic capacitor C 9. The resistor R 9 and the electrolytic capacitor C 9 are connected in series and then connected in parallel with the voltage regulator W l and the electrolytic capacitor C 8. One end is connected to the bridge rectifier circuit D 6. The other end is connected to the negative end of the bridge rectifier circuit D 6, one end of the relay J switch is connected to the filament negative end, and the other end is connected to the resistor R 6 to the positive end of the bridge rectifier filter circuit capacitor C 6. The filament preheating circuit having this structure The working principle is that the mains is rectified into DC power by the step-down circuit C 4 and R 1 after being stepped down by the bridge rectifier circuit D 6, stabilized by the voltage regulator W 1, and then filtered by the electrolytic capacitor C 8 to pass through the resistor. R 9 charges electrolytic capacitor C 9 At this time, the switch of the relay J is on, so that the cathode filament of the DC fluorescent lamp is heated. When the electrolytic capacitor C 9 is charged to the operating voltage of the relay J, the transistor V 2 is turned on to enable the relay; Γ is activated, the relay; The switch of Γ is turned off, the filament preheating is finished, and the lamp is started.

It can be seen from the above that, since the fluorescent tube in the present invention is a DC fluorescent tube with a special structure, the positive electrode filament is not coated with electronic powder, and the positive electrode filament is made thicker than the negative electrode filament. In this way, when the negative electrode of the filament emits electrons to bombard the positive electrode Electron powder will not be sputtered on the positive filament, which avoids the early blackening of the positive pole of the lamp, and the positive filament is slightly thicker than the negative filament, which is more resistant to bombardment, which can prolong the life of the tube. In addition, the present invention adopts a relay filament preheating circuit, so that the DC fluorescent lamp can achieve a successful start-up, which greatly reduces the impact of the fluorescent lamp by multiple starting currents, which can not only improve the life of the lamp, but also Conducive to eye protection. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram of the present invention.

FIG. 2 is a circuit diagram of another embodiment of the present invention. Embodiments of the invention Embodiments of the invention are shown in the drawings. The present invention will be specifically described below with reference to the embodiments shown in the accompanying drawings.

Please refer to Figure 1 first. The strobe-free DC fluorescent lamp includes three parts: a direct current fluorescent lamp tube 2, a DC electronic ballast 1 and a lamp frame. The negative electrode filament 2 2 of the direct current fluorescent tube 2 in the present invention is coated with electronic powder, and the positive electrode filament 2 1 is not coated with electronic powder and is slightly thicker than the negative electrode filament 2 2. The DC electronic ballast 1 in the present invention includes a high-voltage start-up circuit 1 1, a step-down circuit 16, a bridge rectifier filter circuit 1 3, a transistor current stabilization circuit 14, and a relay filament preheating circuit 1 5. As can be seen from FIG. 1, in this embodiment, the high-voltage start-up circuit 11 is a three-times connection of three capacitors C l, C 2, C 3 and corresponding diodes D l, D 2, and D 3. Voltage rectifier circuit. Of course, rectifier circuits with double, quadruple or higher voltage can also be used as high-voltage start-up circuits; bridge rectifier filter circuit 1 3 consists of four diodes D 4, an electrolytic capacitor C 6 and a resistor. R 4 and R 5 are connected (a fluorescent lamp with a lower power, and the resistor R 4 can be omitted), wherein the capacity of the electrolytic capacitor C 6 must be large enough for the fluorescent lamp to have no flicker; the transistor current stabilization circuit 1 4 is composed of a transistor triode VI, The resistors R 7 and R 8 are connected with the electrolytic capacitor C 7. As shown in the figure, the relay filament preheating circuit configured in the DC electronic ballast according to the present invention is composed of the relay J, the transistor V 2 and the bridge rectifier circuit D 6 The voltage regulator W l, the electrolytic capacitors C 8, C 9 and the resistors R 6 and R 9 are connected; the electric power is rectified by C 4 and R 1 of the step-down circuit 1 2 and reduced by the bridge rectifier circuit D 6 DC current, in which the collector of the transistor triode V 2 is connected to a bridge rectifier Road D being 6 The emitter is connected to one end of the relay J coil, the other end of the relay J coil is connected to the negative electrode of the bridge rectifier circuit D 6, the base of the transistor triode V 2 is connected to the resistor R 9 and the positive electrode of the electrolytic capacitor C 9, and the resistor R 9 and The electrolytic capacitor C 9 is connected in series with the voltage regulator W l and the electrolytic capacitor C 8 in parallel. One end is connected to the anode of the bridge rectifier circuit D 6, the other end is connected to the anode of the bridge rectifier circuit D 6, and one end of the relay J switch is connected to the filament. Negative electrode, the other end is connected to the positive electrode of the bridge rectifier filter circuit capacitor through a resistor R 6. The connection relationship between the above circuits is that the high-voltage starter circuit 1 1 and the bridge rectifier filter circuit 1 3 indirectly have an isolation diode D 5 to prevent the high voltage of the high-voltage starter circuit 1 1 from flowing into the bridge rectifier filter circuit 1 3 to cause high voltage. The voltage is reduced, and at the same time, a bridge is provided for the voltage of the bridge rectification filter circuit 1 3 to be applied to the electrodes at both ends of the DC fluorescent tube 2. C 5 and R 2 forming the step-down circuit 16 are connected in parallel with the bridge rectifier filter circuit 1 3 in parallel, and then connected with the high-voltage start-up circuit 1 1 in parallel, and then connected to both ends of the AC power supply. 2 After stepping down, connect a bridge rectifier filter circuit 1 3 to make the voltage output by the DC electronic rectifier consistent with the working voltage required by the DC fluorescent tube. The anode of the high-voltage start-up circuit 1 1 is connected to the anode of the isolation diode D 5, and the anode of the bridge rectifier filter circuit 1 3 is connected to the anode of the isolation diode D 5. The transistor current stabilization circuit 1 4 is connected in series with the DC fluorescent lamp tube 2. As shown in the figure, the transistor current stabilization circuit

The triode VI of 1 4 has a collector connected to the high-voltage lighting circuit 1 1 through a resistor R 3, an emitter connected to the positive pole 2 1 of the DC fluorescent tube 2, and one end of the negative pole 2 2 of the DC fluorescent tube to a bridge rectifier filter circuit 1 3 The other end of the DC fluorescent tube 2 negative 2 2 is connected to the relay filament preheating circuit 1 5 One end of the switch, the relay filament preheating circuit 1 5 The other end of the switch is connected to the resistor R 6 to the bridge rectifier filter circuit 1 3 Capacitor C

6 positive. The DC electronic ballast 1 realizes the preheating of the DC fluorescent tube 2 and the negative filament 2 2, and generates a high voltage to trigger the enlightenment and realize the conversion of AC power to smooth DC power.

FIG. 2 shows another embodiment of the present invention, which is mainly based on the above embodiment and is further provided with a protection circuit. As shown in FIG. 2, the protection circuit is delayed by a current limiting resistor R 1 1 and a thyristor. The conduction circuit is formed in parallel; the thyristor delay conduction circuit is made of thyristor V 3, diode D 8, resistor RIO, voltage regulator W 2 and electrolytic capacitor CI 1 are connected. Diode D 8 and resistor R 1 0 are connected in parallel to the anode of thyristor V 3 and one end of resistor R l 1 The other end is connected to the anode of the zener W 2 and the anode of the electrolytic capacitor C 1 1, the anode of the zener W 2 is connected to the controller of the thyristor V 3, and the anode of the electrolytic capacitor C 1 1 is connected to the thyristor V 3 And the other end of the resistor R l 1. Such a protection circuit is connected in series with the transistor current stabilization circuit to protect the transistor triode VI in the transistor current stabilization circuit. This protection circuit can generally be used on high-power fluorescent lamps (such as more than ¹⁶ watts). If it is a low-power fluorescent lamp, the above protection circuit can only be a current-limiting resistor R 1 1 in series with the transistor current stabilization circuit 14.

Claims

Request for Rights

1. A flicker-free DC fluorescent lamp, including a fluorescent tube, a DC electronic ballast and a lamp frame; the DC electronic ballast includes a high-voltage start-up circuit, a step-down circuit, and a bridge rectifier. Filter circuit, a transistor current stabilization circuit, and a filament preheating circuit; the high-voltage starter circuit and the bridge rectifier filter circuit have an indirect isolation diode, the step-down circuit and the bridge rectifier filter circuit are connected in series, and then connected in parallel with the high-voltage starter circuit. At both ends of the AC power source, the transistor current stabilizing circuit is connected in series with the bridge rectifier filter circuit through an isolation diode and then connected to the positive electrode of the fluorescent tube. One end of the negative electrode of the fluorescent tube is connected to the negative electrode of the bridge rectifier filter circuit. The other end of the circuit and the filament preheating circuit is connected to the anode of a bridge-type rectifier filter circuit capacitor, which is characterized in that: the fluorescent tube of the present invention is a direct current fluorescent tube, and the negative filament of the direct current fluorescent tube is coated with electronic powder and the positive filament. It is not coated with electronic powder and is slightly thicker than the negative electrode.

2. The strobeless DC fluorescent lamp according to claim 1, characterized in that: said filament preheating circuit is a relay filament preheating circuit, which mainly comprises a relay J, a transistor Triode V2, and a bridge rectifier circuit D 6. Voltage regulator W l, electrolytic capacitors C 8 and C 9 and resistors R 6 and R 9; the collector of transistor triode V 2 is connected to the positive pole of bridge rectifier circuit D 6, and the emitter is connected to one end of relay J wire. The other end of the relay J line is connected to the negative electrode of the bridge rectifier circuit D 6, the base of the transistor triode V 2 is connected to the positive electrode of the resistor R 9 and the electrolytic capacitor C 9, and the resistor R 9 and the electrolytic capacitor C 9 are connected in series and then stabilized. The tube W l and the electrolytic capacitor C 8 are connected in parallel, one end is connected to the anode of the bridge rectifier circuit D 6, the other end is connected to the anode of the bridge rectifier circuit D 6, one end of the relay J switch is connected to the anode of the filament, and the other end is connected to the resistor R 6 The positive terminal of the bridge rectifier filter circuit capacitor C 6.

3. The flicker-free DC fluorescent lamp according to claim 1 or 2, characterized in that: The DC electronic ballast circuit also includes a protection circuit, which is formed by connecting the current limiting resistor R l 1 and the thyristor delayed conduction circuit in parallel; the thyristor delayed conduction circuit is routed to the thyristor V 3 The diode D 8, the resistor R 1 0, the voltage regulator W 2 and the electrolytic capacitor C 1 1 are connected. The diode D 8 and the resistor R 1 0 are connected in parallel at one end to the anode of the thyristor V 3 and the resistor R l 1. One end and the other end are connected to the anode of the zener W 2 and the anode of the electrolytic capacitor CI 1, the anode of the zener W 2 is connected to the controller of the thyristor V 3, and the anode of the electrolytic capacitor CI 1 is connected to the thyristor V 3 The negative electrode and the other end of the resistor R l 1.

4. The strobeless DC fluorescent lamp according to claim 3, characterized in that: said protection circuit is a current limiting resistor R 1 1 in series with the transistor current stabilization circuit 1 4.