JP2527620B2 - Discharge lamp lighting device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an inverter type discharge lamp lighting device for lighting a discharge lamp such as a fluorescent lamp at a high frequency, and particularly to lighting two lamps in series by so-called double spots. Discharge lamp lighting device.

[Prior Art] As a conventional discharge lamp lighting device, an inverter that generates a high frequency output of 20 to 100 kHz from a low frequency AC power source such as a commercial power source is used, and a so-called electronic ballast that lights the discharge lamp by the high frequency output ( High-frequency lighting discharge lamp lighting device)
It has been known.

In such an electronic ballast, as shown in FIG. 2, a filament transformer 3 having two center tap type secondary windings 3s1 and 3s3 is used to reduce the filaments 4f1 and 4f2 of a discharge lamp (lamp) 4. Heated by high frequency AC power supply 1,
The high frequency output of the inverter 2 is fed from the intermediate taps c1 and c2 of these secondary windings, so that each filament of the lamp 4 has two bright spots (double spots) 4f1 and 4f2. It is also known.

When the lamp is turned on by a double spot, if the brightness is made equal, the discharge current per spot (bright spot) is halved, and the temperature of each spot is reduced. Since the lamp life is exponentially related to this spot temperature, it is dramatically extended if the spot temperature is reduced. Further, the lamp current can be increased without increasing the spot temperature as compared with the case of a single spot, and high output (high brightness lighting) can be achieved without shortening the life.

[Problems to be Solved by the Invention] By the way, in order to perform double-spot lighting of two lamps, conventionally, following the case of the single lamp of FIG. 2, as shown in FIG. It was preheated with filament winding.

In this case, since the number of taps of the filament transformer is increased and four windings are required, it is necessary to increase the size of the filament transformer or divide the transformer itself into a plurality of pieces. Also,
There was the inconvenience that eight wires were required for the lamp socket.

[Problems to be Solved by the Invention] In view of the above-mentioned problems in the conventional type, an object of the present invention is to provide a discharge lamp lighting device that preheats two lamps at a low frequency and double-series-lights them at a high frequency. It is to realize double spot lighting with a simple configuration.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, in an inverter type discharge lamp lighting device for lighting two discharge lamps in series at a high frequency, a low frequency for forming a double spot. Using the filament transformer of, the filament at both ends is preheated individually with the winding with the center tap,
The inner set of filaments is preheated with a common winding.

[Operation] According to the above configuration, in each filament of the discharge lamp, the voltage applied from the filament transformer causes a potential gradient, and the high frequency output of the inverter is superposed on the potential gradient. Then, if the surface condition of each part of the filament is uniform, the discharge is generated at the part where the potential difference between both filaments of each discharge lamp is the largest. That is, as shown in FIG. 1, at each time point, the low-frequency voltage of the filament whose positive high-frequency output is positive is low from the end where the low-frequency voltage of the positive filament is positive, for example, a ⁺ , b ⁺ . extreme a ^-, b ^- the discharge occurs, two spots to each filament
a ^+, a ^- and b ^+, b ^- is formed.

In the inside of the filament and the connection circuit, the lamp current of one lamp b ^- (a ^-) from the flow toward the ⁺ other lamp a (b ^+), the voltage drop when it is diverted to the filament, the filament The upper potential gradient, that is, the spot becomes unstable or unbalanced. However, this drawback can be easily suppressed to a sufficiently negligible level by lowering the impedance between the terminals of the winding for preheating the inner filament.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a discharge lamp lighting device according to an embodiment of the present invention. In the figure, 1 is a low frequency AC power source such as a commercial power source, 2 is an inverter, 3 is a filament transformer, and 4 and 5 are discharge lamps (lamps) such as fluorescent lamps.

The filament transformer 3 is provided with a primary winding 3p connected to the AC power supply 1, secondary windings 3s1 and 3s3 with a center tap, and a two-terminal secondary winding 3s2 having no setter tap.

In the lamp 4, the filament 4f1 is connected to the center-tapped secondary winding 3s1 of the filament transformer 3, and the filament 4f2 is connected in parallel with the filament 5f1 of the lamp 5 to the 2-terminal secondary winding 3s2 of the filament transformer 3. There is. The filament 5f2 of the lamp 5 is connected to the secondary winding 3s3 with a center tap of the filament transformer 3.

The inverter 2 generates a high frequency output from the AC power supply 1, and its output terminals x and y are connected to center taps provided on the secondary windings 3s1 and 3s3 of the filament transformer 3, respectively.

In this discharge lamp lighting device, preheating power is supplied from the AC power source 1 to the filaments 4f1, 4f2, 5f1 and 5f2 of the lamps 4 and 5 via the filament transformer 3.
Inverter 2 to secondary winding 3 of filament transformer 3
High frequency lamp power is supplied through center taps c1 and c3 of s1 and 3s3. As a result, in FIG.
The phase of the AC power supply 1 in which the next windings 3s1, 3s2, 3s3 are positive on the right side and negative on the left side will be described. In the section where the high frequency output of the inverter is positive on the x side in FIG. No. 3 secondary winding 3s1, the filament 4f1 of the lamp 4 is the easiest point to discharge (for example, the highest potential) a ⁺ , the filament 4f2 of the lamp 4 is the easiest to discharge (for example, the lowest potential point) b ^- , Secondary winding 3s2 of filament transformer 3, filament 5f1 of lamp 5
The lamp current flows through the points a ⁺ and b ⁻ that are most likely to be discharged between the output terminals 5 and 5f2, and the output terminal y of the inverter 2 through the secondary winding 3s3 of the filament transformer 3.

Further, in the section where the high frequency output of the inverter is positive on the y side in FIG. 1, the secondary winding 3s3 of the filament transformer 3 and the b ⁺ point of the filament 5f2 of the lamp 5 and 5 are connected from the output end y.
Inverter 2 via a ^{− of} f1 and secondary winding 3s2 of filament transformer 3, b ⁺ point of filament 4f2 of lamp 4, a ^{− of} 4f1 and secondary winding 3s1 of filament transformer 3.
The lamp current flows through the path extending to the output terminal x of.

That is, in the lighting device, by the polarity of the high-frequency output of the phase inverter 2 of the AC power source 1, the two lamp current path is formed, the filament 4f1 of the lamp 4 a ⁺ point and a ^- to the point, the filament the 4f2 b ⁺ a point and b ^-
There are two spots on each filament 4f1, 4f2, 5f1, 5f2, such as a ⁺ and a ^- points on the filament 5f1 of the lamp 5 and b ⁺ and b ^- points on the filament 5f2. It is formed.

When two spots are formed on each filament 4f1, 4f2, 5f1, 5f2 in this way, in the most preferable state, the current flowing through each spot becomes 1/2 of the lamp current, and the spot temperature becomes a single spot. It can be significantly lower than the case and the lamp life can be extended. Alternatively, the output can be increased without shortening the life as compared with the conventional example of the single spot type.

Thus, in the device of FIG. 1, in comparison with the conventional example of FIG. 3, there are 4 to 3 filament preheating windings, 12 to 8 filament transformer taps, and wiring to the lamp socket. The number can be reduced from eight to six. The configuration can be simplified. Further, the number of windings and taps is reduced, so that the filament transformer can be downsized.

[Effects] As described above, according to the present invention, in a discharge lamp lighting device that lights two lights in a double spot in series, the filament transformer is downsized, the number of taps of the filament transformer is reduced, and the number of wires to the lamp socket is reduced. Double spot lighting can be realized with a simple configuration.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a discharge lamp lighting device according to an embodiment of the present invention, FIG. 2 is a circuit diagram of a conventional discharge lamp lighting device that double-spots one lamp, and FIG. FIG. 4 is a circuit diagram of a conventional discharge lamp lighting device that lights two lights in series with a double spot. 1: Low frequency AC power supply 2: Inverter 3: Filament transformer 3s1, 3s3: Secondary winding with center tap 3s2: Secondary winding without center tap 4,5: Discharge lamp (lamp)

Front page continued (72) Inventor Shigeaki Suzuki 6-78 Minamimachi, Mishima City, Shizuoka Prefecture, Tokyo Electric Co., Ltd. Mishima Plant (72) Inventor Takashi Amano 6-78 Minamimachi, Mishima City, Shizuoka Prefecture, Tokyo Plant, Mishima Factory (56) ) Reference JP 63-187597 (JP, A) JP 63-69195 (JP, A) JP 61-224298 (JP, A) JP 63-308895 (JP, A) 55-55997 (JP, U)

Claims (1)

(57) [Claims] 1. A first and second discharge lamp in which one filament of each is connected in a loop shape, and a first secondary which supplies filament power in parallel to these filaments from a low frequency AC power source. A winding, a second secondary winding with a center tap for supplying filament power from the low-frequency AC power source to the other filament of the first discharge lamp, and the other low-frequency filament to the other filament of the second discharge lamp. A third secondary winding with a center tap for supplying filament power from an alternating current power source, and a high frequency output generated from the low frequency alternating current power source, and the high frequency output is supplied to the center taps of the second and third secondary windings. A discharge lamp lighting device, comprising: an inverter that supplies more power.