JPH0245963Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a flat plate low pressure discharge lamp device using a flat plate low pressure discharge lamp with a flat tube cross section.

(Background Art) FIG. 1 shows a flat plate type low pressure discharge lamp according to a conventional example, in which a pair of opposing electrodes K1 and K2 are provided approximately at the center of both ends of a flat plate type lamp L having a flat tube cross section. A phosphor is coated on the inner surface to constitute a flat plate type low pressure discharge lamp. By applying a DC magnetic field B in a direction perpendicular to the direction of the AC electric field E to such a flat plate type low-pressure discharge lamp, the discharge areas H1 and H2 are alternately deflected, as shown in FIG. A flat plate type low pressure discharge lamp device was proposed which diffused the luminance over the entire flat plate surface to make the luminance uniform (for example, Utility Model Application No. 77726/1983). In the above conventional example, the case where the direction of the magnetic field B is from the back to the front of the paper is explained.

Although this conventional example is effective because the discharge area is diffused as a whole, it still has the following dissatisfied points.

Generally, the size of the flat plate surface that is desired to be used is at most about 30 cm square, and in particular, when it is less than about 20 cm square, the distance between the electrodes becomes extremely short, making it difficult to obtain sufficient efficiency and luminous flux. This is clear from the characteristic diagram shown in FIG. 3, and in the case of low-pressure discharge, the shorter the distance between the electrodes, the lower the radiation efficiency becomes, especially at 50 cm or less, the radiation efficiency decreases significantly.

Although there is a diffusion effect due to the DC magnetic field, it is difficult for the discharge region to cover the entire surface of the flat plate, and it inevitably does not spread to each corner, resulting in weak light emission at each corner.

(Purpose of the invention) The present invention was made to improve the above points, and its purpose is to obtain radiation with higher efficiency and to obtain light emission with uniform brightness over a wider range. The present invention provides a flat plate type low pressure discharge lamp device.

(Disclosure of the invention) Fig. 4 is a diagram schematically showing an embodiment of the invention, in which a flat lamp L having a flat tube cross section and a substantially rectangular light emitting surface shape has a pair of lamps at the diagonal corners. Opposing electrodes K1 and K2 are provided, and a phosphor is coated on the inner surface as required to constitute a flat plate type low pressure discharge lamp.

The lighting frequency of such a flat plate low pressure discharge lamp is
An electric field E of about 100 Hz is applied by a known means, and a DC magnetic field B perpendicular to the flat surface of the lamp L is applied by a known means.

Now, assuming that the direction of the electric field E is from the electrode K2 to the electrode K1 as shown in Figure 5a, and the magnetic field B is applied from the back to the front of the paper, the discharge current is caused by the Lorentz force (F→= i→×B→), the light is deflected in a direction perpendicular to both, that is, to be diffused toward the upper right corner along the flat plate surface. Next, when the direction of the electric field E is reversed and becomes the direction shown in FIG. 5b, it is now deflected so as to diffuse toward the lower left corner. Therefore,
By making the magnetic field B a DC magnetic field and alternating the electric field E, the direction of the Lorentz force changes every half cycle, so that the discharge spreads in alternately opposite directions, and as a result spreads over the entire flat surface. become. And because of the afterimage of the eye, the AC frequency is
If the frequency is 100Hz or higher, the light appears to be emitting from the entire flat surface without flickering.

In the present invention, the electrodes are arranged at diagonal corners, so even if the external dimensions are the same, the distance between the electrodes can be approximately 1.4 to 1.5 times longer than that of the conventional example, and the external dimensions can be reduced. In the case of a flat lamp that is not very large, the effect of improving radiation efficiency is extremely large. In addition, the diffusion region of the discharge due to the magnetic field expands approximately semicircularly in each cycle, so when the electric field is applied diagonally, the diffusion is extremely effective in a rectangular flat lamp, compared to the conventional example. However, the undischarged area becomes smaller.

(Effects of the invention) As described above, the present invention improves the radiation efficiency of a flat lamp whose external dimensions are not so large by arranging a pair of electrodes at the diagonal corners of the flat plate surface. We were able to provide a flat plate type low pressure discharge lamp device in which the discharge area is diffused over the entire flat plate surface and the brightness can be made uniform.

[Brief explanation of the drawing]

FIG. 1 is a simplified diagram of a flat plate type low-pressure discharge lamp according to a conventional example, in which FIG. 1a is a plan view, FIG. Fig. 3 is a characteristic diagram showing the radiation efficiency with respect to the distance between the electrodes, Fig. 4 is a plan view schematically showing an embodiment of the present invention, and Figs. 5 a and b are plane views explaining the operating state of the present invention. It is a diagram. L... Flat lamp, K1, K2... Electrode, E
...Electric field, B...Magnetic field.

Claims (1)

[Scope of utility model registration request] Applying an electric field between a pair of opposing electrodes of a flat low-pressure discharge lamp having a flat tube cross section and a substantially rectangular flat plate surface shape, and applying a magnetic field in a direction perpendicular to the flat plate surface of the lamp, A flat plate low pressure discharge lamp device in which either an electric field or a magnetic field is alternated, characterized in that the pair of electrodes are disposed at diagonal corners of a flat plate surface.