JPH0193093A - Automatic illuminance control device for fluorescent lamp - Google Patents

Abstract

PURPOSE:To make the captioned device suitable for advertising and decorative lights by electronically operating the timing of illuminance variation of a fluores cent lamp, and stagedly and automatically varying the illuminance. CONSTITUTION:The illuminance of a fluorescent tube 1 is made to be stagedly varied in a bright or a dark state by increasing or decreasing a tube current with a frequency periodically and automatically switched after lighting with an commercial alternating current of 50 or 60 cycle supplied in a fluorescent lamp lighting circuit with a power source switch SW closed. For that purpose, a choke coil is used to a stabilizer 2, and a condenser unsuitable in a commer cial frequency is made usable as a stabilizer with an operating frequency made to a high frequency above 400 cycle. Consequently, a tube current can be in creased or decreased in the same manner as a choke coil is used in the stabilizer 2 by periodically and automatically switching a frequency, and a quick or a slow variation can be selectively made. This makes it possible to simplify a circuit constitution and to increase a practical effect.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for advertising and decorative lighting that automatically and stepwise controls the illuminance of fluorescent lights.

Conventionally, most of the fluorescent lamps used for advertising and decorative lights are of the continuous lighting type, have been used for a long time, have little change, and have little eye-catching effect.

In order to solve the above-mentioned drawbacks, the present invention automatically controls the illuminance in a stepped manner after the fluorescent lamp is turned on.
The purpose is to provide advertising and decorative lighting that is rich in variety that has never existed before, and to provide an inexpensive and high-performance device. The present invention will be described in detail below with reference to the drawings. In Figure 1, 1 is a fluorescent tube, filament F1 is a ballast 2 and a starter circuit ST.
The filament F2 is connected to the starter circuit ST and the output terminal Y2 of the frequency conversion circuit 3.

The ballast (choke coil) 2 is connected to the filament Fl and the output terminal Yl of the frequency conversion circuit 3. One side of the commercial AC power supply (50 cycles or 6o cycles) is connected to the input terminal of the frequency conversion circuit 3 via the power switch sw.
1 and the other are connected to input terminals x 2 of the direct frequency conversion circuit 3, respectively. The DC power supply circuit 4 is configured to obtain DC from a commercial AC power supply AC, and its output is supplied as a DC power to the input terminal DC of the frequency conversion circuit 3 and each control circuit. 5 is an initial setting circuit, which is a C-MOS digital IC (I
N V E RT E R1 again +;! The power supply switch SW is short-circuited and the output voltage is fixed at a high level or a low level for a set period of time only at the initial stage when the commercial AC power supply AC is turned on. 6 is a square wave oscillation circuit that has an oscillation stop function and can arbitrarily change the oscillation frequency using a variable resistor VR, and is an unstable circuit composed of a resistor, a capacitor, and a C-MOS digital IC (NAND gate). Using a multivibrator, the oscillation stop input is in the initial setting circuit 5
connected to the output of The output of the square wave oscillation circuit 6 is
C via the input C1 of the frequency conversion circuit 3 and the inverter 7
2 are connected to each other.

The frequency conversion circuit 3 has a built-in inverter, and converts 50 (60) cycles of the commercial AC power supply into 1OO (+20
) cycle, and when the voltage of control input CI is high level and the voltage of C2 is low level, outputs Yl, Y
2 outputs 50 (60) cycles of alternating current, and when the voltage of control input CI is low level and the voltage of 02 is high level, output Y1. It is designed to output 100 (+20) cycles of alternating current to Y2.

The circuit is configured such that the direct current power supply DC is generated at the same time as the switch SW connected to the commercial alternating current power supply AC is short-circuited.

Next, the general lighting characteristics of fluorescent lamps will be explained. If you turn on a fluorescent lamp at the rated tube current and then reduce the tube current, it will continue to light up to a certain value, but if the current is lower than that, it will turn off and will not turn on again. That is, after lighting at the rated current, the illuminance can be controlled by changing the value of the tube current within the dischargeable range.

Various methods can be considered to control the tube current, but the present invention focuses on the fact that when the coil is connected to an AC circuit, the current flowing through the coil can be changed by changing the frequency or self-inductance. , the tube current is controlled by keeping the self-inductance constant and changing the frequency. As a formula (2πf'L)
xl=E, where f is the frequency, L is the self-inductance, ■ is the current, and E is the voltage. (2πfL) in the formula is called inductive reactance, and its unit is ohm, the same as resistance. Therefore, by changing the inductive reactance, you can change the current flowing through the coil, so you can understand that you can change the frequency.

Next, the operation of the embodiment of the present invention will be explained.

At the same time as the power switch SW is short-circuited, a DC power supply DC is generated, and the initial setting circuit 5. Since the square wave oscillation circuit 6° is supplied to the control circuit of the inverter 7 and the frequency conversion circuit 3, the output of the initial setting circuit 5 is used to short-circuit the power switch SW as shown in the voltage waveform diagram indicated by PI in Fig. 2. At the same time, the output voltage is fixed at low level, automatically switched to high level after a certain period of time, and thereafter fixed at high level. Since the oscillation stop input of the square wave oscillation circuit 6 is connected to the output of the initial setting circuit 5, the square wave oscillation circuit 6 outputs a waveform like the voltage waveform shown by R2 in FIG. 2. Since this circuit uses a two-man NAND gate, oscillation is stopped when the oscillation stop input is at a low level, and the output is fixed at a high level when the oscillation stop input is at a low level. The output frequency of this square wave oscillation circuit 6 can be arbitrarily set by adjusting the variable resistor VR. The voltage waveform diagram indicated by R3 in FIG. 2 is the square wave oscillation circuit 6.
The output is inverted by the inverter 7. The control inputs C1 and 02 of the frequency conversion circuit 3 have 1. Second
Since the voltage waveforms shown by R2 and R3 in the figure are supplied, a high level voltage is applied to the control input C1 of the frequency conversion circuit 3 and a low level voltage is applied to C2 for a certain period of time after the power switch SW is shorted. 5 for output Y1 and Y2
Outputs 0 (60) cycles of alternating current and uses ballast (choke coil) 2, fluorescent tube 1. The light is supplied to the starter circuit ST to light the fluorescent tube l. When the output of the initial setting circuit 5 switches from low level to high level, the square wave oscillation circuit 6 switches from the stopped state to the oscillation state, so the output of the square wave oscillation circuit 6 changes from high level to low level, and the frequency The control human power C] of the conversion circuit 3 is inverted from high level to low level, and the control human power C2 is inverted from low level to high level, and the frequency conversion circuit 3 is inverted.
The outputs Yl and Y2 of are 10 from 50 (60) cycles.
Switch to 0 (120), filament F1 of fluorescent tube 1
, F2 is reduced, and the illuminance emitted from the fluorescent tube 1 is reduced. F4 in Figure 2 shows the state of the illuminance generated from the fluorescent tube l. When the output of the initial setting circuit 5 is low level and the square wave oscillation circuit 6 is in a stopped state, the ballast (choke coil) 2 Since 50 (60) cycles of alternating current is supplied, it is in bright state H, and when the square wave oscillation circuit 6 is in the oscillation state and the output is low level, the ballast (choke coil) 2 receives +00 (+20) cycles. Since alternating current is supplied, the tube current decreases and the illuminance decreases, resulting in a dark state.

The present invention is based on the voltage waveform P1 of each part shown in FIG. P2, F3
As can be understood from the illuminance waveform P4 emitted from the fluorescent tube l, when the power switch SW is shorted, the fluorescent lamp lighting circuit
After supplying 0 (60) cycle alternating current and lighting it up, the frequency is periodically and automatically switched to increase or decrease the tube current, and the illuminance emitted from the fluorescent tube 1 is changed stepwise from a bright state F1 to a dark state. It can be controlled.

The example detailed an example in which a choke coil was used in the ballast 2, but if the operating frequency is set to a high frequency of 400 cycles or more, the capacitor, which is inappropriate at commercial frequencies (50 to 60 cycles), can be used as a ballast. It can be used as. There is an electrical formula I = (2πfC)XE,
(2) is the current, f is the frequency, C is the capacitance of the capacitor, and E is the voltage. (2πfC) in the formula is called capacitive reactance, and its unit is ohm, like the reactance and resistance. Therefore, the current can be changed by changing the capacitive reactance (2πfC), so by keeping the capacitance of capacitor C constant and periodically and automatically switching the frequency, it is possible to stabilize the current. Increase or decrease the tube current in the same way as when using a choke coil in device 2,
The illuminance emitted from the fluorescent tube 1 can be controlled stepwise.

In the embodiment, two types of alternating current with different frequencies are alternately switched to control the illumination intensity emitted from the fluorescent tube 1 into two levels, high and low. By adding and sequentially controlling the illuminance, it is possible to control the illuminance in multiple stages.

In the embodiment, the output of the initial setting circuit 5 controls the oscillation and stop states of the square wave oscillation circuit 6, but as another method, an analog switch may be connected to the output of the square wave oscillation circuit 6. Connect the output of the initial setting circuit 5 to the control input of this analog switch, and connect the output of the square wave oscillation circuit 6 and the control input C of the frequency conversion circuit 3.
1 and the input of inverter 7 to high impedance,
It is also possible to set the level of the output voltage in the initial state by pulling up or pulling down the output side of the analog switch with a resistor.

The present invention is capable of automatically changing the illuminance of fluorescent lamps in a step-like manner, and also electronically controls the timing of the change, so it can be adjusted arbitrarily from early to late, which is unprecedented. This automatic illuminance control device for fluorescent lamps is novel and varied, has a simple circuit configuration, and has practical effects for advertising and decorative lighting.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention. FIG. 2 is a diagram of voltage waveforms and illuminance waveforms at various parts in FIG. 1. 1 is a fluorescent tube, 2 is a ballast (choke coil). 3 is a frequency conversion circuit, 4 is a DC power supply circuit, 5 is an initial setting circuit, 6i is a square wave oscillation circuit, 7 is an inverter, AC is a commercial AC power supply, and SW is a power switch.

Claims (1)

[Claims] In a lighting method that supplies AC power to a fluorescent lamp lighting device consisting of a fluorescent tube, ballast, and starter circuit, a commercial AC power source is connected to the input terminal of the frequency conversion circuit, and the output terminal is connected to the input terminal of the frequency conversion circuit. The ballast, the filament built into the fluorescent tube, and the starter circuit are connected in series, and when the commercial AC power source is first turned on, the tube current required to light the fluorescent lamp continues to flow for a certain period of time. In order to An automatic illuminance control device for a fluorescent lamp, characterized in that the frequency of the power supply is automatically switched sequentially to control the tube current, and the illuminance is controlled stepwise and continuously.