JPH04303591A - How to light a high pressure discharge lamp - 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]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for lighting a high pressure discharge lamp.

0002

[Prior Art] Conventionally, lighting devices for general discharge lamps have been large in size and weight because the ballast has been constructed using choke coils, transformers, capacitors, etc., either singly or in combination, in order to stabilize the discharge. Ta.

[0003] For this reason, it is desired that a discharge lamp lighting device be made smaller, lighter, and have improved luminous efficiency, and discharge lamps have been lit at high frequencies.

0004

[Problem to be Solved by the Invention] In addition, high-pressure discharge lamps such as metal halide lamps are known which are lighted at high frequencies and are made smaller, lighter, and have improved luminous efficiency in the same way as the general discharge lamps mentioned above. . However, when a high-pressure discharge lamp is lit at high frequency, the arc fluctuates due to acoustic resonance phenomenon.
There was a problem in that flickering occurred, making the discharge unstable and reducing the luminous efficiency.

[0005] In order to eliminate the occurrence of the acoustic resonance phenomenon, lighting methods have been used in which high-pressure discharge lamps are lit using rectangular waves, third harmonics, or high frequencies of 200 KHz or higher.

However, this lighting method has the problem that the lighting circuit becomes complicated and that it is not possible to sufficiently reduce the size and weight of the device, which is the original purpose of high-frequency lighting.

The present invention has been made in view of the above points, and its object is to provide a high-pressure discharge lamp that eliminates the occurrence of acoustic resonance phenomena, stabilizes the discharge, and allows the device to be made smaller and lighter. The purpose is to provide a lighting method.

[0008]

[Means for Solving the Problems] The present invention provides a lighting method for lighting a high-pressure discharge lamp with a high-frequency voltage, in which the waveform of the high-frequency voltage is a sine wave, and the frequency of the sine wave is 2n times (n
is a natural number) and 1/2n (n is a natural number) is a lighting method for a high-pressure discharge lamp characterized in that a pulse voltage is superimposed on the high-frequency voltage at a frequency other than 1/2n (n is a natural number).

[0009]

[Operation] A pulse voltage at a frequency other than 2n times (n is a natural number) and 1/2n (n is a natural number) the frequency of the sinusoidal high-frequency voltage is superimposed on the high-frequency voltage and applied to the high-pressure discharge lamp.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for lighting a high-pressure discharge lamp according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a lighting circuit in which a lighting method for a high-pressure discharge lamp is adopted. In FIG. 1, reference numeral 1 denotes a high frequency voltage source that outputs a sinusoidal high frequency voltage of 18 KHz or more and 70 KHz or less. A pulse generating circuit 2 and electrodes 4 of a high pressure discharge lamp 3 are connected in parallel between the two poles of this high frequency voltage source 1. The pulse generating circuit 2 generates a pulse voltage into the high frequency voltage at a frequency other than 2n times (n is a natural number) and 1/2n (n is a natural number) the frequency of the sine wave of the high frequency voltage output from the high frequency voltage source 1. Output superimposed.

In FIG. 2, p1 to p3 are 2n times the frequency of the sine wave of the high frequency voltage (n is a natural number) and 1/2n (n
is a natural number).

In this way, by superimposing a pulse voltage on the high frequency voltage of the sine wave at a frequency other than 2n times the frequency of the sine wave (n is a natural number) and 1/2n (n is a natural number), the high pressure discharge lamp 3 Since it is possible to eliminate the occurrence of acoustic resonance phenomena that occur within the arc, fluctuations and flickering of the arc due to acoustic resonance phenomena can be prevented, and the discharge can be stabilized.
This prevents the luminous efficiency from decreasing and allows the device to be made smaller and lighter.

By the way, the acoustic resonance phenomenon that occurs within the high pressure discharge lamp 3 is caused by the generation of standing pressure waves within the high pressure discharge lamp. The compression waves generated by the standing waves are caused by changes in the power input to the high-pressure discharge lamp. That is, when a high-frequency voltage with a frequency of 20 KHz is applied to a high-pressure discharge lamp, 40,000 compression waves are output from the arc of the high-pressure discharge lamp per second. This compression wave collides with the wall of the high-pressure discharge lamp, and a standing wave is generated between it and the wave from the arc.

Therefore, in the above embodiment, the frequency of the sine wave of the high frequency voltage output from the pulse generating circuit 2 is 2n.
Preventing the generation of the standing wave by using a pulse voltage with a frequency other than double (n is a natural number) and 1/2n (n is a natural number),
This prevents the acoustic resonance phenomenon that occurs within high-pressure discharge lamps.

In the above embodiment, the high frequency voltage source 1 outputs a sine wave high frequency voltage, but the sine wave high frequency voltage output from the high frequency voltage source 1 is FM modulated and further output from the pulse circuit. A pulse voltage having a frequency other than 2n times (n is a natural number) and 1/2n (n is a natural number) the frequency of the sine wave may be superimposed.

Further, although it is effective even if the pulse voltage output from the pulse generating circuit 2 is less than the peak value of the high frequency voltage of the sine wave output from the high frequency voltage source 1, it is more effective when the pulse voltage is higher than the peak value. There is.

[0017]

[Effects of the Invention] As detailed above, the present invention provides a lighting method for a high-pressure discharge lamp that eliminates the occurrence of acoustic resonance, stabilizes the discharge, and allows the device to be made smaller and lighter. can be provided.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a lighting circuit in which a lighting method for a high-pressure discharge lamp is adopted.

FIG. 2 is a diagram showing waveforms applied to a high-pressure discharge lamp.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... High frequency voltage source, 2... Pulse generation circuit, 3, High pressure discharge lamp, 4... Electrode.

Claims (1)

[Claims] 1. A lighting method for lighting a high-pressure discharge lamp with a high-frequency voltage, wherein the waveform of the high-frequency voltage is a sine wave, and the frequency of the sine wave is 2n times (n is a natural number) and 1/2.
A method for lighting a high-pressure discharge lamp, characterized in that a pulse voltage at a frequency other than n (n is a natural number) is superimposed on the high-frequency voltage.