JPS59194342A - Low pressure electric-discharge lamp device - Google Patents

Abstract

PURPOSE:To obtain a low pressure electric-discharge lamp device which does not require any stabilizers and is favorably ignited by applying an electric field and a magnetic field in such a manner that Lorentz force constantly acts toward the center of the bulb perpendicularly to both electrodes. CONSTITUTION:An anode 2 and a cathode 3 are installed in an area located in the periphery of the circular cross section of a thin lamp bulb 1 having an almost disk-like upper surface. The bulb 1 is charged with a discharge gas. A glass globe 1a is used to form the bottom surface and the side surface of the bulb 1. The inner surface of the bulb 1 is coated with a phosphor 4. The top wall of the bulb 1 consists of a glass base plate having a reflection film 5 coated with the phosphor 4 on its inner surface. A permanent magnet 6 having its N pole located in its lower side, is affixed to the upper surface of the base plate. A d.c. power supply 7 is connected between the anode 2 and the cathode 3, which is heated with a filament-heating power supply 8. By this applying a magnetic field (B) perpendicularly to applied voltage, Lorentz force acts toward the center of the bulb 1 perpendicularly to the electrodes 2 and 3. Consequently, an electric discharge lamp device which does not require any stabilizers and is favorably ignited, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a low pressure discharge lamp device using a flat low pressure discharge lamp with a flat tube cross section.

(Background technology) Due to its high radiation efficiency, discharge lamps are used as fluorescent lamps, etc.
Widely used as a light source for lighting. However, in terms of discharge physical properties, the electrical characteristics are negative resistance in the general design area, so
A ballast must be inserted in series for current suppression. For this reason, the lighting device as a whole becomes larger, heavier, and
High cost is unavoidable, which is a major drawback depending on the usage situation.

Here, negative resistance means that once the discharge current starts to increase for some reason, ionization is further promoted and the discharge impedance decreases, so the discharge sustaining voltage decreases, the current further increases, and the voltage becomes more and more It refers to the tendency to decline. To explain why this happens in terms of discharge physics, an increase in current means an increase in electrons, and as the number of electrons increases, the probability of ionization collision with the gas increases, resulting in an increase in the generation of ions and electrons, which increases the number of electrons. This is due to the catastrophic process in which electrons are accelerated by an electric field and ionize the gas. In order to prevent these, it is necessary to increase the loss of electrons, that is, to make them disappear more than they are generated through agglomeration, bonding, etc.

(Objective of the Invention) The present invention was made in view of the above-mentioned drawbacks, and its purpose is to provide a low-voltage battery that does not require a ballast and has good starting performance by making the discharge characteristics practically positive. To provide discharge lamp devices.

(Disclosure of the Invention) The present invention will be described below based on Examples. FIG. 1 shows an embodiment of a low-pressure discharge lamp according to the present invention. A pair of electrodes 2.3 are arranged in a thin lamp bulb 1 whose upper and lower surfaces are approximately disc-shaped (as shown in bl). The lamp bulb 1 is disposed facing one end of a circular cross section, and a small amount (several tens of cubic meters) of mercury and several Torr of inert gas such as argon are sealed inside the lamp bulb 1.

The lower and side surfaces of the lamp bulb 1 are formed of a transparent glass globe 1a, and the upper surface is formed of glass or a substrate 1b of iron-chromium alloy or the like whose inner surface is insulated. The edge of the opening and the periphery of the substrate 1b are hermetically sealed with glass frit or the like. The pair of electrodes 2゜3 are supported via an encapsulated wire provided on the substrate 1b, one electrode 2 is an anode plate made of nickel or the like, and the other electrode 3 is an oxidized tungsten coil. It is a cathode filament coated with a thermoelectron emitting substance such as barium, and a phosphor 4 such as calcium halophosphate that converts ultraviolet rays from mercury into visible light is coated on the inner surface of the globe 1a, and titanium oxide, etc. is coated on the inner surface of the substrate 1b. A reflective film 5 that reflects visible light and ultraviolet rays is coated on the surface of the phosphor 4.
covered with. A permanent magnet 6 having a north pole at the bottom is attached to the upper surface of the substrate 1b.

A lamp with such a configuration has a circuit configuration as shown in FIG. 2, that is, a DC power source 7 is connected between the anode 2 and the cathode 3, and a filament heating power source 8 is connected to the cathode filament constituting the cathode 3 to heat the cathode. Then, a discharge occurs between both electrodes 2.3 (point a in FIG. 3), and the discharge voltage between electrodes 2.3 tends to decrease due to rapid ionization promotion. However, since the magnetic field B is applied in a direction perpendicular to the discharge current (or electric field), a Lorentz force f is generated in the direction shown by the arrow in Figure 4, causing the discharge plasma to diffuse to the right in the figure. shall be. Furthermore, since the plasma has a thin space, electrons adhere to and recombine to the wall surfaces (the inner surface of the globe 1a and the inner surface of the substrate 1b) during the diffusion process to a large extent, resulting in an increase in so-called charge loss.

The magnetic field gradient and cross-sectional shape are designed in advance so that this charge loss is greater than the degree of charge generation due to accelerated ionization.
The plasma acts in the direction of increasing the discharge voltage to further promote ionization. As a result, it exhibits a so-called positive characteristic (as the discharge voltage increases as the current increases), and is stably balanced by the externally applied voltage (by the DC power supply 7).
point b in Figure 3). Of course, if there is no magnetic field B, the lamp will show a negative characteristic as shown by the dotted line in FIG. 3, and unless current limitation is applied externally, the current will increase catastrophically, leading to destruction of the lamp. In addition, in FIG. 3, straight line C indicates the rated power supply voltage.

Figure 4 schematically shows how discharge diffusion occurs depending on external voltage. The shaded area in the figure is the discharge area, and the power supply voltage is small in (a) and in (b). Medium, tc) is large. Since the Lorentz force f, which is the driving force for diffusion, is proportional to the current and magnetic field strength, the higher the current, the greater the diffusion, which exerts a self-limiting effect such that the loss of electrons due to recombination increases. Therefore, this shows the positive property.

In this way, it exhibits positive characteristics when a magnetic field is applied, and the Lorentz suppression force acts immediately in response to instantaneous changes in current, so it can stably have an operating point that corresponds to the power supply voltage even without a ballast. . In addition, as in the above embodiment, in the case of a DC power source, the thin permanent magnet 6 can be closely attached, so it is possible to provide an extremely neat lamp without substantially impairing the external shape of the lamp. Since the electrodes are close together, no special starting means is required to start the lamp, and it can be lit with a simple lighting device.

It goes without saying that the present invention is not limited to the above embodiments, and for example, the lamp bulb 1
The shape of the discharge space, that is, the shape of the discharge space may be any shape as long as it has a large spread in the plane direction perpendicular to the magnetic field application direction and has a small thickness in the magnetic field application direction, and the enclosed gas is not particularly limited. Also, there is no need to apply a phosphor, and all that is required is a lamp that produces low-pressure discharge. In addition, it is desirable to arrange the electrodes close to the end of the lamp bulb 1 (close enough to enable direct starting without providing any additional starting means) as shown in Figure 1. The level is rough and the degree of freedom is large. Although it is desirable that the magnetic field B be applied to the entire flat plate surface, the present invention can be implemented as long as it is applied at least near the electrode 2.3. Furthermore, it is not necessary to limit the DC power supply 7 to the AC power supply (an AC power supply may also be used). Although it is somewhat larger and more complex than the example above, it is much more convenient in terms of size, shape, weight, etc. than a lighting device using a normal ballast, and it also allows the electromagnet winding to be used to control the discharge current. If configured in such a way that the magnetic field strength increases or decreases in accordance with the increase or decrease of the current, it is possible to achieve an even more positive characteristic effect.Furthermore, the magnetic field application means does not need to be provided integrally with the lamp; for example, Needless to say, it may be provided in the lighting device main body to which the lamp is attached.

(Effects of the Invention) As described above, the present invention includes disposing a pair of electrodes close to the side edges of a lamp bulb whose cross section is flat and whose upper and lower surfaces are substantially flat, and at the same time disposing a discharge body within the bulb. A low-pressure discharge lamp device comprising a sealed low-pressure discharge lamp that is lit by applying an electric field between the two electrodes and applying a magnetic field substantially perpendicular to the flat plate surface of the bulb, wherein the applied electric field and the applied magnetic field are is applied so that the Lorentz force is always perpendicular to the distance between the two electrodes and acts in the direction of the center of the bulb, so that the discharge characteristics can be made to be practically positive. Therefore, it is possible to provide a low-pressure electric lamp device that does not require a ballast like the conventional low-pressure discharge lamp device and that can be easily started.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the low-pressure discharge lamp according to the present invention, (al is a cross-sectional view, (bl is a bottom view, FIG. 2 is a diagram showing an example of the circuit configuration according to the present invention, and FIG. The figure is a voltage/current characteristic diagram of a low-pressure discharge lamp, and FIGS. 4(a) to (C+ are diagrams schematically showing discharge diffusion in a low-pressure discharge lamp according to the present invention. Agent for patent applicant Matsushita Electric Works Co., Ltd.) Person Patent attorney Toshimaru Takemoto (2 idiots) 1 procedure Neho Seisho (Voluntary supplementary date December 22, 1980 Commissioner of the Patent Office 1, Date of display of the case 58 years Patent side No. 069813 2, The name of the invention is 1, 1, 1, 3, and the person making the amendment.Relationship with the case.Patent applicant address: 1048 Kadoma, Kadoma City, Osaka Prefecture.
Name (583) Matsushita Electric Works Co., Ltd. Representative: Iku Kobayashi 4, Agent address: 1048-226 Kadoma, Kadoma City, Osaka Prefecture

Claims (3)

[Claims] (1) The above-described low-pressure discharge lamp is constructed by disposing a pair of electrodes close to the side edges of a lamp bulb whose cross section is flat and whose upper and lower ends are substantially flat, and by enclosing a discharge body within the bulb. A low-pressure discharge lamp device that is lit by applying an electric field between both electrodes and a magnetic field substantially perpendicular to the flat plate surface of the bulb, in which the Lorentz force always directs the directions of the applied electric field and applied magnetic field. 1. A low-pressure discharge lamp device characterized in that a voltage is applied perpendicularly to the center of the bulb and acts toward the center of the bulb. (2) A low-pressure discharge lamp device according to claim 1, in which a phosphor is coated on the inner surface of the lamp bulb to provide mercury discharge. (3) The low pressure discharge lamp device according to claim 1 or 2, wherein the applied electric field is a DC electric field, and the applied magnetic field is a DC magnetic field.