JPS59141158A - Plate-type discharge lamp device - Google Patents

Abstract

PURPOSE:To essentially unify the whole intensity on a plate surface by applying a rotating magnetic field at a nearly right angle to the plate surface of a discharge lamp in a plate-type discharge lamp having a flat tube cross section and provided with a pair of electrodes in the tube center. CONSTITUTION:A plate-type discharge lamp 2 with a round plate surface is provided inside an annular rotating-magnetic field generator 1. The inner surface of the discharge lamp 2 tube is coated with a phosphor and the inactive gas of several Torr and a suitable amount of mercury is sealed inside. Electrodes 3a, 3b are coated with an electrode material, and the electrodes 3a, 3b are connected to external circuits with connection wires 4. The generator 1 is constituted so that three-phase AC currents Ia, Ib, Ic flow through coils Ma, Mb, Mc respectively, and a rotating magnetic field is generated by the instantaneous current at phases I , II, III. The positive voltage is applied to the electrode 3b and the negative voltage is applied to the electrode 3a to perform discharge, plasma is also rotated by the rotation of the magnetic field, thus essentially unifying the whole intensity on the plate surface.

Description

[Detailed description of the invention] (Technical field) The present invention relates to a flat discharge lamp device having a flat tube cross section.

(Background technology) Conventional 2. So-called flat lamps with a flat tube cross section have been proposed, and some have even been commercialized. Since this type of lamp emits light from its entire surface, it is thought to create a new field of lighting as a surface light source. However, uniform brightness cannot be obtained by simply changing the shape of the lamp into a flat plate. In other words, in Figure 1 fat,
As shown in (b), when the tube A is turned on, the brightness is high in the center of the tube A and becomes darker toward the periphery, which is a drawback in that uneven brightness occurs. This is because the discharge occurs at the shortest distance between the two electrodes B (traversing the path that minimizes the discharge energy). Note that the shaded area C in the figure indicates the discharge area.

In addition, as an improved version of the above-mentioned drawback, Fig. 2 (al, (
As shown in b), it has been proposed that multiple partition plates are provided inside the lamp tube A to make the discharge area C meander to make the brightness uniform, but this makes the lamp structure unnecessarily complicated. However, it has the drawbacks of being difficult to manufacture and heavy.

(Object of the Invention) The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a flat discharge lamp device that has a simple configuration and has substantially uniform brightness over the entire flat surface of the discharge lamp. It is on offer.

(Disclosure of the Invention) The present invention applies a calibrated value field substantially perpendicular to the flat plate surface of a flat discharge lamp having a flat tube cross section and a pair of electrodes at the center of the tube, thereby increasing the brightness of the entire flat plate surface. It is made to be substantially uniform. .

The present invention will be explained below based on examples.

Embodiment 1 Figure 3 (al, (bl) shows the first embodiment of the present invention, in which 1 is an annular rotating magnetic field generator, 2 is a flat plate discharge lamp with a circular flat plate surface, and the inner surface of the tube is is coated with a phosphor, and the tube is filled with several Torr of inert gas and an appropriate amount of mercury.3a and 3b are electrodes coated with an electrode material, and may be hot cathodes.4 is This is a connection line that electrically connects the electrodes 3a, 3b and an external circuit.

Embodiment 2 FIGS. 4(a) and 4(b) show a second embodiment of the present invention, in which the electrode part of Embodiment 1 is improved, and a recess 5 is provided in the center of the tube, and the recess 5 is A connection line 4 is provided. Note that one electrode 3b is formed in a ring shape.

Embodiment 3 FIGS. 5(al) and (bl) show a third embodiment of the present invention, in which a cylindrical portion 6 with an open top end is formed in the center of the tube, and one electrode 3a is disposed within the cylindrical portion 6. However, the other electrode 3b is arranged in a ring shape around the outer periphery of the cylindrical portion 6.

Next, the operation of the rotating magnetic field generating device 1 with such a configuration will be explained. The rotating magnetic field generating device 1 used in the present invention has a structure similar to the stator of an induction motor, and the case of three-phase alternating current will be described.

Three-phase alternating currents 1a, Ib as shown in FIG.

rc is a winding Ma as shown in FIG.
, Mb, and Mc, the magnetic fields generated by the instantaneous currents in phases r, n, and m shown in FIG. 6 are as shown in FIG. 7, tag, fbl, and (C), respectively. As is clear from FIG. 6, the phase angles from phase (1) to phase (2) and from phase (2) to phase (2) are each 30°, and the three-phase alternating currents 1a, Ib.

The direction of the magnetic field created by Ic is also rotated by 30°. In other words, while the phase of the current shifts to GO'', the magnetic field also changes by 60
°, and thus a rotating magnetic field is obtained.

We have described the case of obtaining a rotating magnetic field using three-phase alternating current, but if you want to generate a rotating magnetic field using single-phase alternating current, the coil of the rotating magnetic field generator 1 should be wound in a round coil type, or by using a capacitor. If you use a split-phase type capacitor using , you can obtain a rotating magnetic field even with single-phase AC.

Next, the relationship between the rotating magnetic field and discharge will be described based on FIG. Fig. 8 (al is a plan view, bl is a cross-sectional view, and the magnetic field is in the direction indicated by the arrow line H in Fig. 8 (a),
In the figure fbl, a voltage is applied in the direction from the front to the back of the paper, and in the figure (bl), a positive voltage is applied to the lower electrode 3b and a negative voltage is applied to the upper electrode 3a, causing discharge.

In such a state, electrons in the plasma are subjected to Lorentz force, and the plasma P meanderes as shown in fbl in the figure. The meandering of the plasma P is viewed from above as shown in the same figure (al). Therefore, when the magnetic field rotates as described above, the plasma P also rotates, and the entire flat surface of the discharge lamp 2 appears to be emitting light. , FIG. 9 shows an example of a connection state between the discharge lamp 2 and an external circuit. In the figure, 7 is a lighting circuit, 8 is a rotating magnetic field generating circuit connected to the rotating magnetic field generating device 1, and 9 is a power source.

In addition, by changing the above Lorentz force, the first
As shown in Figure 0 (al, (bl), it is possible to change the degree of deflection of the plasma P from Pl to P2 in the figure, and therefore the area of the discharge region can be changed, so the dimming of the discharge lamp 2 can be adjusted. In other words, the Lorentz force F is F=qVB (q is the charge, ■ is the speed of the charge,
B is the magnetic flux density), and when the discharge current is changed, qv is changed, and when the current flowing through the winding of the rotating magnetic field generator 1 is changed, the magnetic flux density B is changed. Therefore, by changing the discharge current or the current flowing through the windings using the rotating magnetic field generating circuit 8, the Lorentz force can be easily changed.

(Effects of the Invention) As described above, the present invention provides a flat discharge lamp having a flat tube cross section and a pair of electrodes at the center of the tube by applying a rotating magnetic field substantially orthogonal to the flat surface of the discharge lamp. , it was possible to provide a flat discharge lamp device with a simple configuration in which the luminance of the entire flat plate surface is substantially uniform.

[Brief explanation of the drawing]

Fig. 1 and Fig. 2 respectively show conventional examples, and Fig. 1 (a
1 is a plan view, FIG. 1 is a sectional view, FIG. , in each figure (
(a) is a diagram, and (b) is a cross-sectional view. Figure 6 is a diagram showing three-phase AC, Figure 7 +aL (bl, (C1 is a diagram explaining the operation of the magnetic field generator, respectively, and Figure 8 is a diagram showing the relationship between the direction of the magnetic field and discharge, ta) (b) is a plan view, (b) is a cross-sectional view. Fig. 9 is a block diagram showing an example of the connection state between the discharge lamp and the external circuit, Fig. 10 is an explanatory diagram when changing the Lorentz force, and ra) is a cross-sectional view. Plan view, (bl is a sectional view. 1... Rotating magnetic field generator, 2... Flat discharge lamp, 3
a, 3b...electrode, 4...connection line. Patent applicant Matsushita Electric Works Co., Ltd. Agent Patent attorney Toshimaru Takemoto (Two idiots)

Claims (1)

[Claims] (1) A flat discharge lamp device comprising a flat discharge lamp having a flat tube cross section and a pair of electrodes at the center of the tube, and a rotating magnetic field application means that is substantially orthogonal to the flat surface of the discharge lamp.