DE2053517A1 - Device for feeding a gas and / or vapor discharge lamp - Google Patents

Description

Dipl.-Inn- MORHT AUER

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Anmsli'r :::. · -. :.; .- Α3, ΐΕΚΕΜ

- ■■ PHN- 4415

Registration dated »Oct. 30, 1970

Device for supplying a gas and / or vapor discharge lamp

The invention relates to a device with a low pressure gas and / or vapor discharge lamp, two input terminals of the device being connected in series at least the lamp and a switching element are connected and the switching element is connected to a control device which controls this switching element in such a way that an intermittent current flows through the lamp, with a time interval of ¥ seconds, during which the lamp is traversed by current, at least one an equally long, practically currentless time interval of R seconds follows. "

Low pressure is understood here to mean a pressure of a maximum of 150 Torr.

A known device of the type mentioned is, for. B. in French patent 1,456,460. One advantage of this known device is a relatively high light output (e.g. in lumens / watt). In that described in this French patent

PHN 4415

Xr -Z-

109821/1323

Execution form is the time W equal to the time R. If

W to increase the light output, the ratio would be chosen to be less than 1/2, while the larapen output (in watts) is kept constant, the current peaks could have such a high intensity that material would quickly sputter off the lamp electrodes, affecting the life of the lamp would.

The aim of the invention is to create a device in which the light output of the discharge lamp is very high and the life of this lamp is long.

According to the invention, a device of the type mentioned at the beginning is characterized in that, in order to achieve a condition favorable to light generation, the pressure in the discharge space is at least 4 Torr and, moreover, is so high that the condition Cg <& _{D is} met, the ratio W / (W + R) <0.4 and the duration of a period W + R of the lamp supply has a value between 2 π. Zg and 2 π. T ^, where Tg represents the energy relaxation time (in seconds) and Lj _{3 represents} the diffusion time (in seconds) of the electrons in the discharge space.

Energy relaxation time is understood here to mean: Ä. B, where A = the mean, fractional energy loss per collision of an electron (under fractional becomes here understood that the energy loss is expressed in the energy of the electron before the collision) and B = the mean number of collisions of an electron with other non-electron particles in the discharge space per second is.

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Diffusion time is understood here as the time (in seconds) that an electron needs on average, to reach the wall of the discharge space.

An advantage of the device according to the invention is that the light output can be very high as a result of the relatively low value of the ratio between the current conduction time (W) and the practically currentless Time (R) on the one hand and as a result of a certain range of the period duration (W + R) on the other hand and then also to use a lamp with a relatively high pressure in the discharge space. Another advantage is that the relatively high pressure in the discharge space counteracts the sputtering of the electrodes. This can in a device according to the invention, the lamp also have a long service life.

The invention is also based on the knowledge that with the selected period W + R the electron gas cools during the currentless time interval as a result of collisions until it has reached the temperature of the neutral gas, while the electron concentration is only slightly reduced in this time interval. The degree of the reduction in concentration is determined by the diffusion time L · which is longer than the time interval

W + R
, while the amount of decrease in the mean electron energy is determined by the energy relaxation time Cg, which is shorter than the time interval

W + R
2 η *

The current pulse following a currentless time interval heats the electron gas again and it is shown that that a relatively large number of fast electrons

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is obtained, d. i.e., a greater number than under one corresponding ratio for direct current operation of the lamp by the same average current. The efficiency of a Gas discharge is favorably influenced in the presence of a relatively large number of fast electrons.

The discharge space can, for. B. a noble gas, e.g. B. argon, and / or a metal, e.g. B. mercury.

In an advantageous embodiment of the invention, at which is the gas in the discharge space is neon, the neon pressure is 5 to 25 Torr and the ratio is maximum 0.3 and the duration W + R of a perlode of the lamp

—5 —5 feeding between 4.10 ^ and 50.10 ^ see.

This preferred device has the advantage that the achievable light output with a suitably selected Pressure can even be six times that of a lamp with direct current supply (with the same lamp power).

The invention is explained in more detail with reference to the drawing; show it:

1 shows a circuit arrangement of a device according to the invention;

Fig. 2 shows another embodiment of the switching part of the Contraption;

Fig. 3 shows a further embodiment of the switching part £ he device.

In Fig. 1 1 and 2 designate terminals for DC voltage source of z. B. 200 V. The clamped 1

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one

and 2 are connected in series with a discharge lamp 3, a ballast resistor 4 and the main electrodes of a transistor 5 connected to one another. The base of the transistor is connected to a pulse generator tied together. There is also a connection point between the lamp 3 and the emitter of the transistor 5 and the pulse generator 6 tied together. The pulse generator 6 is fed via terminals 7 and 8, which are connected to an alternating current network from 220 V, 50 Hz are connected.

The pulse generator 6 is set in such a way that pulses with a duration of about 25 / usec are generated, with λ each pulse being followed by a rest time of about 100 / usec.

The lamp 3 is a neon lamp with an operating voltage of about 150 V (with direct voltage supply). The length this lamp is about 750mm and the diameter is 36mm. The pressure of the neon gas is about 10 torr. That The electrode material is tungsten with a barium oxide coating.

In this practical case, the frequency is about 8000 Hz. In this case, T _n is about 1000 / usec and T _{E is} about 2.5 / usec. The sum W + R is about 125 / Usec. The condition that W + R is between 2 π. T _n and 2 π. L "lie

w soll is thus fulfilled. Furthermore = 0.2.

For comparison with other sources of the lamp, the table below shows the data for a normal DC current supply and a state in which = 0.5, and finally a state in which = 0.2. The latter case is an example according to the invention. The table shows the results for a Lamp with a pressure of neon gas of 10 torr and at

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a comparable lamp with a print of neon from 5 torr. The numbers in the table show the relative lumen values of the lamp in the different states as a percentage of the lumen value of the 5-Torr lamp with direct current operation. (The lumen value of the latter lamp at Direct current feed was about 540 lumens with a consumed lamp power of 45 watts). The frequency of the the cases given in the two right-hand columns were always 8 KHz. In all cases indicated in the table the lamp power was 45 watts.

pressure DC power supply W. W. W. W _no 5 torr
10 torr 100
50 + R ^{0> 5} + R ^u '* - 120
180 200
300

From these results it can be seen that a lamp according to the invention (see last column) has a higher luminous efficiency (e.g. in lumens / watt). This table also shows that the higher the pressure, the higher the pressure the light output is even greater than at a low pressure. This higher pressure still brings a lower one Sputtering of electrode material of the lamp with it.

The life of the lamps in a device according to the invention was not shorter than the usual life known discharge lamps with direct current operation.

When the lamp through a low-frequency alternating current network is to be fed, the transistor 5 'can be converted into a

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Rectifier bridge (diodes 10 to 13) according to FIG. 2 are included. In Fig. 2, 3 ¹ denotes the lamp to be fed and 6 ¹ the pulse generator.

When feeding from a low-frequency alternating current network, two transistors could also be used which are accommodated in branches parallel to one another and have opposite forward directions. This is illustrated in FIG. The transistors are labeled 15 and 16. A diode 17 is switched on in series with transistor 15 and a diode 18 in series with transistor 16. The bases of transistors 15 and 16 are connected to a ^l a pulse generator ^6!. The emitters of the two transistors are also connected to the pulse generator 6 ″. The lamp to be powered is labeled ^{3 11.} The diodes 17 and 18 serve to protect the transistors.

In the cases of Figures 2 and 3, a number of current pulses followed by rest intervals through the lamp in one direction are followed by a number of current pulses followed by rest intervals through the lamp in the other direction. This is due to the fact that here the power is supplied by a low frequency AC power source with a frequency of less than 100 Hz; but the pulse generators load (

drive the transistors at a much higher frequency (around 8000 Hz).

In the examples described, a pulse generator always operates a lamp circuit. However, it is possible a pulse generator more than one lamp circuit (e.g. indicated by the series connection 1, 4, 5, 3, 2 in Fig. 1) operate so that only one pulse generator is used to control the supply of a group of lamps will.

Claims : 109821/1323

Claims (4)

Claims ί \ ϊ Device with a low-pressure gas and / or vapor discharge lamp, wherein two input terminals of the device are connected by a series connection of at least the lamp and a switching element and the switching element is connected to a control device that controls this switching element in such a way that the lamp of an intermittent current is flowed through, with a time interval of W seconds, during which the lamp is flowed through by current, followed by an at least equally long, practically currentless time interval of R seconds, characterized in that to achieve a condition favorable to light generation, the pressure im Discharge space is at least 4 Torr and is also so high that the condition T "< t _{D is} met, where the ratio is less than 0.4 and the duration of one period w + R W + R of the lamp supply has a value between 2 π. L- and 2 π. L _D , where T _{E is} the energy relaxation time (in seconds) and ~ _{D is} the diffusion time (in seconds) of the electrons in the discharge space. 2. Device with a discharge lamp according to claim 1, wherein the gas in the discharge space is neon, characterized in that the pressure of the neon is about 5 to 25 Torr and is a maximum of 0.3 and the duration W + R of a period of lamp supply between 4.1 O ^-5 and 5Ο.1Ο " ⁵ see. 3. Device with a discharge lamp according to claim 1 or 2 for connection to an AC voltage network 1 0982 1/1323 with a frequency of less than 100 Hz, characterized in that the switching element consists of a transistor (5 ^f ) which is connected in a diagonal of a rectifier bridge (10 to 13). 4. Device with a discharge lamp according to claim 1 or 2 for connection to an AC voltage network with a frequency of less than 100 Hz, characterized in that the switching element consists of the combination of two transistors (15,16), which in two parallel branches are added and have an opposite direction of passage. " 109821/1323 ta Blank page