JPH05325910A - Noble gas electric discharge lamp device - Google Patents

Abstract

PURPOSE:To restrain surface creepage on a bulb surface and miniaturize an electric discharge lamp device by fixing a phosphor layer on the inner wall of a tubular glass bulb, sealing noble gas including mainly xenon(Xe) gas inside the bulb, attaching a pair of band-like electrodes to the outer wall of the bulb, and applying a high frequency voltage between the electrodes to light the lamp device. CONSTITUTION:A phosphor layer 3 is attached on the inner surface of a glass bulb 1, which is sealed with noble gas including mainly Xe gas. A pair of band- like electrodes 4, 5 each made of an aluminum foil are disposed on the outer wall of the bulb 2. A high frequency voltage of 50kHz or higher is applied to the electrodes 4, 5, thus lighting an electric discharge lamp device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular glass bulb whose inner wall is coated with a phosphor layer, in which a rare gas containing xenon gas as a main component is sealed, and a pair of strip electrodes are provided on the outer wall of the glass bulb. The present invention relates to a rare gas discharge lamp device in which a high frequency and a high voltage are applied between both strip electrodes so as to light.

[0002]

2. Description of the Related Art A so-called outer wall electrode type rare gas discharge lamp 1 in which a pair of strip electrodes are arranged on the outer wall of a glass bulb of this type is shown in FIG. The phosphor layer 3 is deposited on the inner surface, and a rare gas containing xenon gas as a main component is added therein at 30 torr to 100 torr.
The glass bulb 2 is sealed with a gas pressure of r and a pair of strip electrodes 4 and 5 made of aluminum foil are arranged on the outer wall of the glass bulb 2 so as to face each other over substantially the entire length of the bulb shaft. In the rare gas discharge lamp 1 having such a structure, as shown in FIG. 2, a commercial frequency power source 6 is provided by a high frequency lighting circuit 7 such as an inverter.
For example, when converted into a high frequency and high voltage of about 20 to 30 KHz and 2 KV and applied between the strip electrodes 4 and 5, the internal space of the glass bulb 2 sandwiched between the strip electrodes 4 and 5,
Discharge of the xenon gas (excitation line wavelength 147 nm) is generated in the direction orthogonal to the valve axis. Then, the discharge of the xenon gas excites the phosphor layer 3 attached to the inner wall of the glass bulb 2, and the visible light is emitted to the outside of the bulb 2. The rare gas discharge lamp 1 having such a structure is characterized in that the bulb diameter is small and the discharge is rare gas, so that the brightness and the discharge voltage are hardly affected by the ambient temperature, and that the bulb has no electrode and thus has a long life. In recent years, attention has been focused on a light source for reading originals of OA equipment.

[0003]

By the way, the outer wall electrode type rare gas discharge lamp 1 having such excellent features is as follows.
A high-frequency high voltage is applied to the internal discharge space via the glass bulb 2 from the two strip electrodes 4 and 5,
A high lamp voltage of 1700 V to 1800 V (RMS) was required to maintain the discharge. Therefore, a high-voltage transformer is required for the inverter device of the high-frequency lighting circuit 7, dielectric breakdown of the output terminal portion, the surface of the glass bulb 2 between the outer wall electrodes 4 and 5 of the rare gas discharge lamp 1 itself, There were problems such as creeping discharge. Therefore, the high-frequency lighting circuit 7 is required to have high insulation and becomes expensive, and the circuit board of the high-frequency lighting circuit 7 and the glass bulb diameter of the rare gas discharge lamp 1 are required to be large, which makes it difficult to downsize the device. there were.

Therefore, the present invention has been made in view of the above, and an object thereof is to obtain a rare gas discharge lamp device which can achieve insulation protection of a high frequency lighting circuit and downsizing of the device.

[0005]

Therefore, as a result of intensive studies by the present inventors, a high frequency voltage is applied to the inner space of the outer wall electrode type rare gas discharge lamp of the present invention through the glass bulb wall from both outer wall electrodes. As a result, the resistance in the thickness direction of the glass bulb and the electrostatic capacitance formed in the space between the two electrodes through the glass bulb add impedance to the discharge in the bulb. Then, paying attention to the fact that the electrostatic capacitance changes depending on the lighting frequency of the power source to be applied, it was wondered whether the present rare gas discharge lamp could be driven for lighting at a lower operating voltage. Then, with the lamp current maintained at a predetermined constant value, the lighting frequency is set to the conventional 20 to 30 KH.
The change in the operating voltage of the lamp with respect to the lighting frequency was investigated by changing the range from z to 100 KHz. As a result, the lamp voltage drastically decreases from the conventional voltage of several thousand to several hundred volts with the increase of the lighting frequency, and after that, when the lighting frequency exceeds 50 KHz, the lamp voltage hardly decreases, and the lamp voltage decreases. It was found that a nearly equilibrium state was reached. Therefore, according to the present invention, based on the result of the discharge characteristic investigation, the outer wall electrode type rare gas discharge lamp is lit by a high frequency lighting circuit having a frequency of 50 KHz or more.

[0006]

According to the above investigation results, the outer wall electrode type rare gas discharge lamp of the present invention maintains the lamp current at a predetermined constant value and sets the lamp voltage to several hundred volts by setting the lighting frequency to 50 KHz or more. Lighting can be driven with a substantially minimum lighting voltage. In this case, since the rare gas discharge lamp maintains the lamp current at a predetermined constant value, the lamp illuminance maintains a substantially predetermined brightness. In the present invention, the fact that the operating voltage of the lamp initially decreases with the lighting frequency means that the electrostatic capacitance formed in the space between the electrodes via the glass bulb decreases with 1 / jwC as the frequency increases. This is because the resistance in the thickness direction of the glass bulb increases with an increase in frequency when the frequency exceeds 50 KHz, and the impedance as a whole reaches approximately equilibrium. It

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an outer wall electrode type rare gas discharge lamp 1 according to the present invention.
The correlation diagram between the lighting frequency and the lamp voltage when the lamp current is kept constant is shown. Here, the rare gas discharge lamp 1 has the same structure as that of FIG.
Is a lead glass having an outer diameter of 6 mm, a wall thickness of 0.5 mm and a length of 300 mm, a filling gas is xenon gas of 65 torr, and outer wall electrodes 4 and 5 are an aluminum foil having a width of 6 mm and a length of 300 mm. Then, a high frequency lighting circuit 7 as shown in FIG. 4 was connected to both outer wall electrodes 4 and 5, and a characteristic test was conducted. In the test, the power supply voltage was adjusted so that the lamp current was constant at 20 mA and 25 mA, and the lighting frequency was 20K.
In the range of Hz to 100 KHz, the voltage was varied in 5 KHz steps, the lamp voltage at that time was measured, and characteristic curves A1 and A2 as shown in the drawing were obtained.

As is clear from the figure, the lamp current 25
The curve A1 of mA is located about 500 V higher than that of the curve A2 of lamp current 20 mA, but both curves A1 and A2 have a lamp voltage of 1600 V, respectively, as the lighting frequency increases up to 50 KHz. 2100
The voltage drastically decreases from V to about 600V and 750V, and thereafter, the lamp voltage does not decrease so much even if the lighting frequency is increased and is in a substantially balanced state. In this test, both curves A1 and A2 had a lighting frequency of 20 KHz.
In the following, flickering occurred in the discharge and it became unstable.

FIG. 2 shows illuminance curve data measured at a position 8 mm away from the outer wall of the central portion of each bulb in the above characteristic test. Illuminance curves B1 and B2 correspond to lamp currents of 20 mA and 25 mA, respectively. is doing. Although the illuminance values of the curves B1 and B2 slightly decrease with the increase of the lighting frequency, they are in the practical range (LX) or more, and there is no particular problem in actual use.

[0010]

As described in detail above, according to the present invention, a phosphor layer is deposited on the inner wall of a tubular glass bulb, and a rare gas containing xenon gas as a main component is sealed inside, and the outer wall of the glass bulb is sealed. In a rare gas discharge lamp device in which a pair of strip-shaped electrodes are additionally provided and a high-frequency pressure is applied between both strip-shaped electrodes for lighting, a high frequency of 50 KHz or higher and a high voltage are applied between the pair of strip-shaped electrodes. Since the rare gas discharge lamp is configured to light up, the lamp voltage can be lowered without significantly lowering the illuminance, and the problem of insulation of the high frequency power supply device and the rare gas discharge lamp device is solved, It is possible to deal with miniaturization and cost reduction.

[Brief description of drawings]

FIG. 1 is a characteristic curve diagram of an outer wall electrode type rare gas discharge lamp of the present invention.

FIG. 2 is an illuminance curve diagram of an outer wall electrode type rare gas discharge lamp of the present invention.

FIG. 3 is a partially cutaway sectional view of an outer wall electrode type rare gas discharge lamp to which the present invention is applied.

FIG. 4 is a high frequency lighting circuit of the discharge lamp of FIG.

[Explanation of symbols]

 1 Noble gas discharge lamp 2 Glass bulb 3 Phosphor layer 4, 5 Strip electrodes

Claims (1)

[Claims] 1. A phosphor layer is deposited on the inner wall of a tubular glass bulb, a rare gas containing xenon gas as a main component is enclosed therein, and a pair of strip electrodes are attached to the outer wall of the glass bulb.
In a rare gas discharge lamp device in which a high frequency voltage is applied between both strip electrodes to turn on, a high frequency voltage of 50 KHz or more is applied between the pair of strip electrodes.