JP2614221B2 - Variable color control device for cold cathode discharge tubes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to a lighting control device for a cold-cathode discharge tube called a neon sign, and in particular, a single discharge tube is made of, for example, red, blue and the like. The present invention relates to a device that performs variable color control to intermediate colors.

<Prior Art> Originally, one discharge tube emits only one color. Therefore, when multi-color display is performed with the current neon sign, neon signs having different emission colors are arranged by the number of colors and electrically switched. The method is taken.

On the other hand, Japanese Patent Publication No. 53-42386 discloses a technique for changing the emission color by changing the waveform of a current flowing through one discharge tube.

This principle will be briefly described. The neon sign tube uses a gas filled with Ne + Hg. FIG. 5 shows the excitation levels of mercury and neon. The excitation level of the red-orange to red spectrum of neon is around 18 eV, and that of visible light of mercury is
The excitation level of mercury at 253.7 nm is about 4.88 eV, around 8 eV.

By utilizing these level differences, the emission spectrum is selected by controlling the electron energy in the discharge tube. FIG. 6 shows a principle circuit diagram for controlling the electron energy in the discharge tube.
The discharge tube 1 is connected in series with the electronic switching element 2 and connected to the DC power supply 3 to perform pulse discharge. This circuit emits blue light without increasing the electron energy in the discharge tube when the ratio τ / T of the energization time τ and the pause time T is large, as shown in FIG. 7A, for example. As shown in b), when τ / T is small, the electron energy in the discharge tube increases, and red light is emitted.

However, various problems arise when trying to put this principle into practical use. For example, one of the neon sign booster transformers
Since a large current of several tens of amperes flows in the secondary winding, a method of switching the intermediate tap of the transformer winding using a contact type switch is not practical because of problems of contact damage and electric noise.

Therefore, the present inventors, according to Japanese Patent Application No. 61-119686,
A variable color control device for a discharge tube which has no contact type switch, generates no electric noise, and has excellent durability, that is, a DC power supply, a capacitor, an inductance and a step-up transformer 1.
A secondary side is connected in series to form an LC resonance circuit, a semiconductor switching element is connected in parallel with this inductance, and the resonance frequency of the LC resonance circuit is changed by turning on or off the semiconductor switching element to emit blue or blue light. A variable color control device for switching to red has been proposed.

<Problems to be solved by the invention> When one neon sign is caused to emit a variable color light in this manner, the above-described problem occurs, and the power control for controlling the light emission color is delicate, so adjustment is performed. There is a problem that the work is difficult and requires skill. Accordingly, an object of the present invention is to provide a variable color control device that can be easily and reliably performed by anyone.

<Means for Solving the Problems> The variable color control device for a cold cathode discharge tube of the present invention generates a pulse train having a desired frequency and duty by a combination circuit of an impedance element and a switching element.
In a device for controlling the light emission of a cold cathode discharge tube filled with neon gas and mercury gas by boosting this pulse train by a boosting transformer, an oscillator for generating a predetermined frequency, and a memory in which information of red light emission and blue light emission is described A setting device for instructing the selection of an address of the memory; a pulse train output means for outputting a pulse train of a predetermined frequency and a predetermined duty based on output information of the memory; and an open / close switch for applying the pulse train to the switching element to perform on / off control. It is characterized by having control means.

Further, according to the present invention, the first pulse train output in which the cold cathode discharge tube generates red power and the second pulse train output in which blue light is emitted can be alternately switched and output at a predetermined time ratio. In this case, the discharge tube continuously emits an intermediate color between red and blue.

<Operation> When the user selects, for example, blue light emission from the setting device, the address of blue light emission in the memory is selected, and information such as the frequency and duty required for blue light emission is output from the memory, and the switching element is turned on / off in accordance with the information. Is done. Similarly, red light emission and intermediate color light emission can be selected by the setting device.

<Embodiment> FIG. 1 shows a circuit diagram of an embodiment of the present invention.

Terminals R and S are connected to a commercial AC power supply line. Full-wave rectifier 1
1 is full-wave rectified commercial AC power supply, smoothing capacitor 12,
The resistor 13 smoothes the pulsating flow. These constitute the DC power supply 14.

First and second thyristors 18 and 19 are connected in series to this DC power supply 14, and a series circuit of a primary winding 151 of the step-up transformer 15 and a capacitor circuit 17 is connected in parallel with the second thyristor 19. , A neon tube 22 on the secondary side of the step-up transformer 15
And the capacitor 16 are connected. As the step-up transformer 15, a leakage type transformer having an air gap in the core is used.
The capacitor circuit 17 is configured by a series connection of, for example, a capacitor 17a of several tens of microfarads and a triac 20 and a parallel circuit of, for example, a capacitor 17b of microfarads.When the triac 20 is on, a parallel circuit of both capacitors is formed. When it is off, the circuit has only the capacitor 17b.

The thyristors 18 and 19 and the triac 20 are controlled by control signals K ₁ , G ₁ , K ₂ , G ₂ , K ₃ and G ₃ of the control circuit 21. In addition,
In the figure, a circuit 153 introduced from the secondary side of the step-up transformer 15 to the control circuit 21 is a control circuit power supply.

FIG. 2 shows another embodiment of the present invention. In this embodiment, an intermediate tap is provided in the primary winding 151A of the step-up transformer 15A, and a series circuit of, for example, a capacitor 17c of several tens of microfarads and a triac 20c is connected to the intermediate tap. For example, a series circuit of a capacitor 17d of several microfarads and a triac 20d is connected to the terminal. A leakage type transformer is used for the step-up transformer 15A.

FIG. 3 is a block diagram showing the internal configuration of the control circuit 21.
The oscillator 23 outputs, for example, a 3 kHz square wave or a sine wave, and this output is frequency-divided by a frequency dividing circuit 24 and introduced into a blue light emission pulse generating circuit 25.
A square wave of 0 Hz is output and introduced into the red light emission pulse generation circuit 26. These pulse generating circuits 25 and 26 are constituted by, for example, a differentiating circuit. The output signal of the frequency dividing circuit 24 is input to the counter 27. The counter 27 forms an address selection circuit of the memory 28, and an address according to the state (count value) of the counter is designated. The memory 28 stores red and blue information for each address. Also,
This memory can also be used to store a neon sign display program. The setting device 29 is used when fixing the state of the counter 27 to a desired one. At this time, the neon sign continuously emits a predetermined color tone. Color identification circuit 30
Decodes the output information of the memory 28 to control the pulse selection gate 31, and controls the driving of the third pulse transformer 35. The pulse selection gate 31 selectively passes either the red light emission pulse signal or the blue light emission pulse signal and inputs the same to the flip-flop 32. The flip-flop 32 is, for example, a T-type flip-flop, and the state is inverted each time a pulse is input. The driving of the first pulse transformer 33 is controlled by the output Q of the flip-flop 32, and the driving of the second pulse transformer 34 is controlled by the complement output.

FIG. 4 (a) shows a firing signal of each switching element 18, 19, 20 when emitting red light, and FIG. 4 (b) shows an ignition signal of each switching element when emitting blue light. When the red light emission, by firing a G ₃ in synchronism with the G _1, G _2, to maintain the triac 20 in the on state, G ₁ and G ₂
Are fired at a cycle of, for example, 3.9 ms to charge and discharge the two capacitors 17a and 17b simultaneously. Capacitor circuit 17
Is large, the rising of the pulse input to the step-up transformer 15 becomes sharp, and relatively large energy is given to the neon tube 22. When the blue light emission, keeping the triac 20 without providing the completely firing signal to the G ₃ to the OFF state,
And firing at a cycle of both example 0.3mS the G ₁ and G ₂ is charged and discharged only capacitor 17b having a small capacity. This capacitor 17b
Since the primary winding 151 of the step-up transformer 15 is inserted in the charge / discharge circuit of FIG. 1, the impedance is delayed, the rising of the pulse input to the step-up transformer 15 becomes slower, and less energy is consumed than in the red light emission. Granted to 22.

When it is desired to emit light in an intermediate color between red and blue, the ignition signal shown in FIG. 9A and the ignition signal shown in FIG.
The output may be switched every time, and the color tone of the intermediate color can be changed by changing the time ratio between the two. Such information of the intermediate color emission can be written in the memory 28 in advance, and can be selected and designated by the setting device 29.

The thyristors 18 and 19 in the above embodiment can be implemented by replacing this with a transistor.
20, 20c, 20d can be implemented by replacing this with another AC switch.

<Effects of the Invention> According to the present invention, the emission color of a discharge tube such as a neon sign can be stably changed by a simple and inexpensive circuit configuration. Further, the user can easily give an instruction to select a variable color.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a circuit diagram showing another embodiment of the present invention, FIG. 3 is a block diagram showing a configuration example of the control circuit 21 of FIG. FIG. 5 is a diagram illustrating the operation of the above embodiment, FIG. 5 is a diagram illustrating the principle of the present invention, FIG. 6 is a circuit diagram illustrating the prior art, and FIG. 7 is a diagram illustrating the operation of FIG. 14 DC power supply 15 Step-up transformer 17 Capacitor circuit 17a, 17b, 17c, 17d Capacitor 18 First switching element 19 Second switching element 20 Third switching element 21 …… Control circuit 22 …… Discharge tube

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaaki Kimoto 8-2 Higashi-Ashigaoka, Ikoma (56) References JP-A-62-276795 (JP, A) JP-A-57-61298 (JP, A) Kohei 5-3706 (JP, B2) JP-B 54-3314 (JP, B2)

Claims (2)

(57) [Claims] 1. A pulse train having a desired frequency and duty is generated by a combination circuit of an impedance element and a switching element, and the pulse train is boosted by a step-up transformer, and has neon gas and mercury gas in the tube having electrodes only at both ends of the tube. In a device for controlling light emission of a cold cathode discharge tube in which is enclosed, an oscillator for generating a predetermined frequency, a memory in which information of red light emission and blue light emission are described, and a setting device for instructing address selection of the memory, A cold-cathode discharge, comprising: pulse train output means for outputting a pulse train of a predetermined frequency and a predetermined duty based on output information of the memory; and switching control means for applying the pulse train to the switching element to perform on / off control. Variable color control device for tube. 2. The output according to claim 1, wherein the output of the first pulse train for emitting red light and the output of the second pulse train for emitting blue light are alternately switched at a predetermined time ratio. Variable color control device for cold cathode discharge tubes.