JPS62154497A - Stable burning of discharge tube for neon signs - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for stably lighting a discharge tube for a neon sign using high-frequency current (for example, a method for stably lighting a discharge tube for a neon sign without producing a striped pattern of light and darkness). .

In recent years, as a method of lighting discharge tubes for neon signs, a conventional neon transformer (instead of the conventional neon transformer), a high frequency inverter circuit is used to light the discharge tube with a high frequency current of several to several tens of KHz.
2. Description of the Related Art Techniques to make power supply devices smaller and lighter are being developed and put into practical use.

This method of using high-frequency current is similar to ordinary outdoor neon signs, and when multiple discharge tubes are connected in series or complicatedly bent to express characters or figures, the discharge tubes can be placed in bright places.・A striped pattern consisting of two alternating dark areas occurs, which is not practical (:).Therefore, this lighting method is only useful (
= Practical only for small neon signs for indoor decoration (not too much).

The present invention was devised for the purpose of preventing the occurrence of this striped pattern and making lighting using high-frequency current practical even in outdoor neon signs.

That is, the present invention is characterized in that lighting is performed by a high-frequency current having an asymmetric voltage waveform in which a missing portion is formed in the increasing portion from the zero point or the decreasing portion to the zero point in the positive or negative half wave of the sine wave. This is a stable lighting method for neon sign discharge tubes.

The voltage waveform used in this invention is specific (see Fig. 1, 6).
1, lb), le), and (d), where (&) is the missing part 1 formed in the increasing part from the zero point of the positive half wave, and (b) is the positive half wave. (cl is formed in the increasing part from the zero point of the negative half-wave, (dl is formed in the decreasing part from the zero point of the negative half-wave) It is something that

The frequency is about 1 to 100 KHz, preferably 4 to 100 KHz.
30 KM, and the voltage is 500 to 1 per meter of discharge tube.
500' When a discharge tube for a neon sign is lit using the above high frequency current, no striped pattern is generated (Stable 4: It works.

Although the mechanism by which this striped pattern occurs and its prevention is unknown, this operation has been experimentally confirmed.

It is known that as a method of preventing bending of the discharge path, that is, the light emitting part, which occurs when a high-pressure discharge lamp such as a metal halide lamp is lit with high-frequency current, it is known to make the C2 voltage waveform asymmetrical as in the present invention. (Unexamined Japanese Patent Publication No. 59-1
Publication No. 4297). In this case, the operating mechanism has been clarified: bending of the discharge path occurs due to resonance C2 between the sound waves generated inside the tube of the high-pressure discharge lamp and the applied high frequency, and the current with an asymmetrical waveform has the effect of preventing this resonance. ing.

However, in the case of the present invention, the operating mechanism is presumed to be completely different, since the pressure inside the discharge tube for neon signs is as low as a few μHg.

Next, two examples of circuits that generate waveforms according to the present invention will be described.

First, a circuit 10 for generating a normal sinusoidal voltage shown in FIG. 2 will be described. This circuit 1o includes a voltage switching circuit 13' having transistors 11, 12 and a DC power supply 14 and a positive terminal 15. Connect with ground terminal 16,
At the output terminal 17 of the voltage switching circuit 13.

The primary winding 18a of the output transformer 18 and the coil 19 are connected in series, and this coil 19 is connected to the capacitor 20.
The positive terminal 15 is connected to the ground terminal 16 via the capacitor 21, and the neon sign discharge tube (not shown) is connected from the secondary winding 18b of the output transformer 18 to the output terminals 22 and 23. ).

In this circuit 10, the transistors 11 and 12 alternately perform on-off operation, and when the transistor 11 is in the on state, the positive terminal 15 is connected to the transistor 11. Output Lance 18. Current charging capacitor 21 via coil 19 and transistor 11° output voltage 18 from capacitor 20. A discharge current flows through the coil 19 @ and conversely, when the transistor 12 is on, the coil 19 charges the capacitor 20. Dekadrance 18
, the current flowing to the ground terminal 16 via the transistor 12 and the coil 19° output transformer 1 from the capacitor 21.
8. A discharge current flows through transistor 12.

That is, the voltage V17 at the output terminal 17 of this circuit 1o is
As shown in the figure (ml), it is a rectangular wave whose maximum value is the voltage vc of the DC power supply, and the voltage v22,2
3 is carp/I/19. :7 days? 20.21 and the load actance result in a sine wave with a phase shift as shown in FIG.

Here, point 2 between transformer 18 and coil 19 of circuit 10
4, this voltage V24 is obtained by subtracting a voltage similar to the output voltages V22 and V23 from the voltage V17 at the output terminal, and has a waveform as shown in FIG. 4(b), and the transistor 11 is in the on state, when the voltage of the glass terminal, that is, the voltage of the DC power supply becomes 70 or more,
When the transistor 12 is in the on state, there are times when the voltage at the ground terminal 16 becomes less than zero. Therefore, if no current flows through the output transformer during this period, the waveform of the present invention can be obtained.

That is, the waveform of the present invention is obtained by the g2-summing circuit 110 in FIG. This circuit 110 is exactly the same as the circuit 1o described above, and the only difference is that a diode 125 is used to connect a point 124 between the output transformer 118 and the coil/L/119 to the ground terminal 116. Note that in this figure (:), locations C corresponding to each location of the circuit 1o are indicated by adding 100 to their reference numerals.

Therefore, this circuit 110 also operates in the same manner as the circuit 1o. However, during the period when the voltage at point 124 should be negative, it is short-circuited to the ground terminal 116 by the diode 125 and becomes zero as shown in FIG. The waveform shown in (b) is output.

The circuit 110 described above is an example of a circuit for implementing the present invention, and the waveforms of the present invention may be realized by various circuits.

As described above, in the present invention, when lighting a discharge tube for a neon sign with a high-frequency current, the voltage waveform is made asymmetrical in the two missing parts near the zero point of the sine wave technique, so that a bright and dark striped pattern is created. can be prevented from occurring. Therefore, it is possible to use high-frequency current to light even large, outdoor-use discharge tubes connected in series and complicatedly bent, making it possible to make the image device smaller and lighter. .

[Brief explanation of drawings]

Figure 1 is a graph showing the voltage waveform used in the present invention, Figure 2 is a graph showing the voltage waveform used in the present invention.
The figure is a circuit diagram showing a circuit that generates a normal sine wave voltage, FIG. 3 is a circuit diagram showing a circuit that generates a voltage waveform of the present invention,
FIG. 4 is a graph showing voltages at various parts of the circuit shown in FIG. 3, and FIG. 5 is a graph showing voltages at various parts of the circuit shown in FIG. 1... Missing part. Figure 1 Figure 2 Diagram Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. A neon light that is lit by a high-frequency current having an asymmetrical voltage waveform in which a missing part is formed in the increasing part from the zero point or the decreasing part to the zero point in the positive or negative half wave of a sine wave. Stable lighting method for sign discharge tubes.