JPH0138880Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention integrates a fluorescent lamp and a high-frequency lighting circuit for lighting the fluorescent lamp in an envelope equipped with a base. This invention relates to a fluorescent lamp device that can be used by being directly inserted into an incandescent lamp socket.

[Technical background of the invention and its problems]

Conventionally, the lighting circuit for this type of device generally used a chiyoke ballast type ballast, but recently, in order to make the lighting circuit smaller and lighter and improve lighting efficiency, the above-mentioned type of ballast has been used. Attempts have been made to use high frequency lighting circuits in place of choke ballast type ballasts.

As this high-frequency lighting circuit, a circuit configuration shown in FIG. 1 is considered, but in such a high-frequency lighting circuit, the high-frequency conversion circuit 101
There is a problem that radiation noise is generated from the circuit elements that make up the circuit, especially the inductor devices such as the output transformer 102 and the current limiting transformer 103 through which the main current flows, leading to radio interference. Even with the use of an EI core, it was not possible to sufficiently reduce the radiation noise.

Generally speaking, as a measure to reduce this radiated noise, it is known to completely cover the area around the noise source with a metal cover and ground this cover, but as mentioned above, this method is used to replace incandescent light bulbs. In a fluorescent lamp device, it is nearly impossible to ground it easily.

Moreover, if the inductor device, which is a source of noise, is hermetically covered with a cover, air permeability and heat dissipation will deteriorate, so self-heating during circuit operation will damage the core, windings, transistors, etc. of the inductor device. There is a risk that overheating will cause dielectric breakdown between the windings, magnetic flux saturation of the core, or thermal runaway of the transistor, and the thermal effect on various circuit elements such as other capacitors and semiconductors will also become greater.

Therefore, it may be possible to create ventilation holes on the circumferential surface of the cover, but this would ensure some degree of ventilation for the circuit elements, but
The presence of holes makes it easier for radiated noise to leak,
There is a drawback that the noise reduction effect may be insufficient in some cases.

[Purpose of invention]

The present invention was developed based on the above circumstances, and it is an object of the present invention to provide a fluorescent lamp device that can efficiently reduce radiation noise without interfering with heat dissipation from circuit elements.

[Summary of the idea]

That is, in order to achieve the above purpose, the present invention
Various circuits including a transparent envelope having a base, a fluorescent lamp housed within the envelope, and an inductor device housed within the envelope and using a closed magnetic circuit core on one side of a circuit board. The above-mentioned circuit comprises a high-frequency lighting circuit for lighting a lamp in which elements are arranged, and a conductive member having a loop shape or a shape close to a loop shape and covering the outer periphery of the high-frequency lighting circuit while housing the high-frequency lighting circuit therein. Among the elements, the inductor device which is a noise generation source is characterized in that the loop direction of the magnetic field focused on the core of the closed magnetic circuit is made to match the loop direction of the conductive member.

[Example of idea]

An embodiment of the present invention will be described below with reference to FIGS. 2 to 6.

In the figure, reference numeral 1 denotes a cover made of synthetic resin, which is formed into a bowl shape with a circumferential surface shaped like a paraboloid of revolution. A base 2 is attached to the top of one end of the cover 1, and an opening at the other end is covered with a light-transmitting synthetic resin or glass globe 3. The globe 3 has a substantially spherical shape, and the cap of the globe 3 forms an envelope 4 in the shape of a ball bulb. A curved tube-shaped fluorescent lamp 5 and a high-frequency lighting circuit 6 for lighting the fluorescent lamp 5 are integrally housed within the envelope 4. This fluorescent lamp 5 is constructed by bending a straight glass bulb with electrodes 7 sealed at both ends into a substantially U-shape at the center between both ends 8, 8 to form a curved portion 9. By bending the curved portion 9 and both end portions 8, 8 into a substantially U-shape in a direction substantially perpendicular to a plane including the U-shape, the curved portions 9 and 9 They are called saddle-shaped fluorescent lamps because their overall shape resembles a horseback saddle. A predetermined amount of mercury and an inert gas are sealed inside the bulb of the fluorescent lamp 5, and a phosphor coating is coated on the inner surface. Such a fluorescent lamp 5 is supported with its both ends 8, 8 and curved portion 9 facing the cover 1 side, and although this support structure is not shown in detail, in the case of this embodiment, Both end portions 8, 8 and bent portion 9 are connected to a pair of support walls 10, 10 led out from the top side of one end of the cover 1.
It is configured to be locked in place.

On the other hand, as shown in the block diagram in FIG. The cycle is inputted to a full-wave rectifier circuit 12 through a line filter circuit 11 for noise absorption, and the full-wave rectifier circuit 12 converts it into direct current and outputs it, and further converts this output voltage into a high-frequency converter circuit 1.
4, it is converted to a high frequency voltage and output. The high frequency lighting circuit 6 is connected to the fluorescent lamp 5 via the cap 2 and the current limiting transformer 16.

Each circuit 11 to 14 of the high frequency lighting circuit 6 is a fifth
As shown in FIG. 6 and FIG. 6, the circuit board 17 is arranged on a flat circuit board 17. Therefore, on the same surface of the circuit board 17, various circuit elements, that is, the current limiting transformer of the high frequency conversion circuit 14 are arranged. 16, output transformer 18, and base coil 28 for improving switching characteristics, transistors, resistors,
Circuit elements 19 such as capacitors are attached and connected to a predetermined circuit configuration by a printed wiring layer (not shown). In addition, here, current limiting transformer 1
6, output transformer 18 and base coil 28.
A closed magnetic circuit core 26 such as an EI core is used. And the circuit elements 16, 1 on the circuit board 17
On the back surface opposite to the surface on which 8, 19... are arranged, a layer with a thickness of, for example, 1
A conductive member 21 made of an aluminum plate with a diameter of approximately 1.0 mm is closely attached, and a bottom plate portion 21a of the conductive member 21 covers the entire back surface of the circuit board 17. Bottom plate part 21
Two portions of the outer surrounding portions at both ends of a are folded back together toward one side of the circuit board 17, and at the tips of the rising walls 23, 23 of these folded portions 22, 22, the circuit board 17 Facing walls 24, 24 are formed to face each other at a distance substantially parallel to one surface, and the tips of these facing walls 24, 24 are as follows.
As shown in FIG. 5, they are spaced apart and facing each other on the circuit board 17. Therefore, such folded parts 22, 22 and the bottom plate part 2 on the back side of the circuit board 17
1a form a loop, and in the inner part surrounded by the folded parts 22, 22 and the bottom plate part 21a, there is a current limiting transformer on the circuit board 17, which is the main source of noise among the circuit elements. 16, an output transformer 18, a base coil 28, and other inductor devices are arranged. In this case, both the transformers 16, 18 and the base coil 28
As shown in FIG. 6, the loop direction of the closed magnetic circuit core 26, that is, the direction of the magnetic field focused on the closed magnetic circuit core 26, is set to the opposite direction of the facing walls 24, 24, that is, the folded portions 22, 22. Bottom plate part 21
It is arranged in the inner part in a posture that matches the direction of the loop formed by. Therefore, the loop direction of the closed magnetic circuit core 26 in which the magnetic flux density is highest is the direction in which the walls 23, 2 of the folded portions 22, 22
4 and the bottom plate portion 21a.

Note that reference numeral 27 in FIG. 4 is a starting circuit for the fluorescent lamp 5, which is arranged on the circuit board 17 together with the high frequency lighting circuit 6.

According to such a configuration, the current limiting transformer 16 and the output transformer 18, which are sources of noise, are installed in the inner part surrounded by the bottom plate part 21a that covers the back surface of the circuit board 17 and the walls 23 and 24 of the folded parts 22 and 22. In addition, these transformers 16 and 18 direct the direction of the magnetic field focused on the core 26, that is, the loop direction of the closed magnetic circuit core 26, to the folded portions 22,
22, so that the loop direction of the closed magnetic circuit core 26 where the density of magnetic flux is the highest corresponds to the direction of the loop formed by the facing walls 24, 24 of the folded portions 22, 22. 24 and bottom plate part 2
It will be continuously covered by 1a. Therefore, the magnetic field generated during circuit operation is absorbed by the folding part 2.
2, 22 and the bottom plate portion 21a, and as a result, the intensity of radiated noise is reduced, and adverse effects such as radio wave interference on surrounding equipment can be suppressed.

According to experiments conducted by the present inventors, the radiation noise intensity can be reduced by 2 to 3 dB compared to the case where the loop direction of the closed magnetic circuit core 26 of the inductor device does not match the loop direction of the conductive member 21. Confirmed.

Further, the conductive member 21 includes folded portions 22, 2.
Various circuit elements 16, 1 on the circuit board 17 other than 2
8, 19, 28... Since there is no part that covers these circuit elements 16, 18, 19, 2...
8... are not sealed, and especially in the case of this embodiment, there is also a gap between the folded parts 22, 22, so that sufficient ventilation can be ensured for the circuit elements 16, 18, 19, 28... . Therefore, the heat dissipation of the circuit elements 16, 18, 19, 28, etc. is not hindered, which prevents magnetic flux saturation and dielectric breakdown of transformers, as well as heat damage to other capacitors and semiconductors, and improves circuit operation. This has the advantage of increasing reliability.

Note that when providing the folded portions 22, 22, as in the other embodiment shown in FIG. The outer periphery of the coil 28 may be covered in a complete loop. In this case, the area with high magnetic flux density is completely covered, so that the magnetic field shielding effect can be further enhanced.

Further, in the above-described embodiments, the fluorescent lamp has a saddle shape, but it may be U-shaped, for example, and the shape of the envelope is not limited to the ball bulb shape.

[Effect of idea]

According to the present invention described in detail above, the loop direction of the closed magnetic circuit core where the magnetic flux density is highest is surrounded by conductive members in a loop shape, so that the magnetic field generated during circuit operation is It is efficiently shielded by the conductive member, and therefore radiation noise can be reduced without interfering with the heat dissipation of the inductor device as well as various circuit elements on the circuit board.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a high-frequency lighting circuit showing the technical background of the invention, Figs. 2 to 6 show an embodiment of the invention, Fig. 2 is a sectional view of the entire device, and Fig. 3 is a circuit diagram of a high-frequency lighting circuit showing the technical background of the invention. FIG. 4 is a block diagram of the high-frequency lighting circuit, FIG. 5 is a plan view of the high-frequency lighting circuit, FIG. 6 is a cross-sectional view taken along the line in FIG. 5, and FIG. FIG. 3 is a sectional view showing another embodiment of the present invention. 2...Base, 4...Envelope, 5...Fluorescent lamp, 6...High frequency lighting circuit, 16, 18, 19,
...Circuit elements, inductor devices (current limiting transformers,
output transformer, base coil), 17... circuit board, 21... conductive member, 21a... bottom plate part, 22
...Folding section, 26...core.

Claims (1)

[Scope of utility model registration request] It includes a transparent envelope having a cap, a fluorescent lamp housed in the envelope, and an inductor device housed in the envelope and using a closed magnetic circuit core on one side of a circuit board. A high-frequency lighting circuit for lighting a lamp in which various circuit elements are arranged, and a conductive member having a loop shape or a shape close to a loop shape and covering the outer periphery of the high-frequency lighting circuit while accommodating the high-frequency lighting circuit therein, A fluorescent lamp device characterized in that the loop direction of the magnetic field focused on the core of the closed magnetic path of the inductor device among the circuit elements is made to match the loop direction of the conductive member.