JPS581509B2 - low pressure gas discharge lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in low-pressure gas discharge lamps, and more particularly to a single-capped fluorescent lamp that is miniaturized by using a double-tube discharge vessel.

Conventional low-pressure gas discharge lamps, as typified by fluorescent lamps for general lighting, have electrodes installed at both ends of an elongated glass tube, and a rare gas (or
It is made by enclosing rare gases and metals such as mercury.

Therefore, in a straight tube type fluorescent lamp with caps at both ends, the tube length is 120 cm for a 40W lamp.
63cm with 30W lamp, 58c with 20W lamp
m, and this length is inconvenient and undesirable depending on the usage situation.

From this point of view, there have recently been expectations for the development of single-ended lamps that are as short and bright as possible.

Therefore, an object of the present invention is to create a small, bright, single-capped, low-pressure gas discharge system by using a discharge vessel with a double tube structure and stably forming multiple lines of discharge plasma in the discharge vessel at the same time. The purpose is to provide electric light.

In order to achieve the above object, the present invention uses a discharge vessel having a double tube structure consisting of an outer bulb and an inner glass tube coaxially disposed inside the bulb and having one end open. By providing a single cathode inside the holder and a plurality of anodes outside the inner glass tube, and simultaneously causing a direct current discharge between each of the plurality of anodes and the single cathode. The present invention is characterized in that the discharge current is divided into a plurality of discharge paths corresponding to each of the plurality of anodes at the open end of the inner glass tube.

Hereinafter, the present invention will be described in detail with reference to embodiments.

FIG. 1 shows an embodiment of the present invention, in which an inner glass tube 2 with one end open is installed approximately coaxially within a sealed outer glass bulb 1.

The other end of the inner glass tube 2 is adhesively fixed to a stem 3 provided at the base of the outer glass bulb 1 with an inorganic adhesive or the like, and is closed.

The inner and outer surfaces of the inner glass tube 2 and the inner surface of the outer glass bulb 1 are coated with a phosphor.

The stem 3 is a filament cathode 4 coated with an electron emitting material.
The flare part of the stem 3 has a plurality of anodes 5.
is installed.

A notch 6 is provided at the tip (open end) of the inner glass tube 2 at a position corresponding to each anode.

Inside the outer glass bulb 1, a low-pressure rare gas (for example, argon gas of several torr) and a small amount of mercury are sealed.

A discharge lamp with this structure has a ballast 7, a diode bridge 8,
Direct current lighting can be performed by connecting to a commercial AC power source via a lighting circuit consisting of a glow lamp 9 and a discharge current shunt 10.

In the lighting state, the discharge plasma 11 flows into the inner glass tube 2.
As shown by hatching in the figure, on the outside of the inner glass tube 2, the flow is divided into multiple strips between each anode 5 and the notch 6 corresponding to each anode. It is formed by

The discharge current shunt device 10 is for equally dividing the current value of the discharge plasma divided into multiple lines, and is not necessarily necessary to simply divide the discharge current into multiple lines. This is effective in eliminating imbalance between each discharge current value.

The figure shows an example of using a current balancer with a single-turn transformer structure as this discharge current shunt, but in some cases, an impedance such as a resistor is connected in series with each anode, thereby dividing the discharge current equally. The effect is the same no matter what you do.

An example of the dimensions of the discharge bulb of the embodiment is as follows.

Maximum outer diameter of outer bulb 1: 90 mm Outer diameter of the apex of outer bulb: 47 mm Outer diameter of root of outer bulb: 57 mm Outer diameter of inner glass tube: 32 mm Distance between anode tip and inner glass tube tip: approx. 150 mm Number of anodes and Number of notches = 2 Distance between the inside of the outer bulb and the tip of the inner glass tube:
5-30mm Shape of cutout: Rectangular Depth of cutout: 5N20mm Width of cutout (arc length) = 10-25mm Enclosure: Mercury and argon gas 1.5-3.0 torr inner glass The discharge plasma 11 within the tube 2 is unified as a whole, and this unified discharge plasma is stabilized by the inner wall surface of the inner glass tube.

At the tip (open end) of the inner glass tube 2, the plasma 11 is 2
The discharge path is divided into two, forming two folded discharge paths, each leading to the corresponding anode 5.

During this period, the space between the outer glass bulb 1 and the inner glass tube 2 is widened, so each plasma is diffused and spreads sufficiently in the lateral direction (circumferential direction), resulting in a nearly uniform plasma throughout the discharge vessel. filled with.

The discharge plasma is stable here as well, and is considered to be stabilized by the outer wall surface of the inner glass tube 2 and the inner wall surface of the outer glass bulb 1.

Note that in order to sufficiently stabilize the plasma near the anode 5, it was effective to make the surface area of each anode exposed in the discharge space considerably smaller.

Furthermore, even if the notch 6 is not provided at the tip of the inner glass tube 2, if the axial symmetry of each part of the lamp is good, the plasma 11 can be stably and evenly divided. This has the effect of making it possible to perform sufficiently stable branching even if the axial symmetry of

Since the notch 6 has the function of making it easier for the discharge current to flow through that position, the position of each discharge plasma separated at the tip of the inner glass tube 2 is fixed there, thereby creating a discharge path. This has the effect of preventing flickering of light that occurs due to fluctuations in the light.

FIG. 2 shows another example of the shape of the notch 6 provided at the tip of the inner glass tube 2. FIG.

That is, in this example, the periphery of the open end of the inner glass tube 2 is gently recessed at a position 6 corresponding to each anode 5.

In this case as well, the same effect as in the case of the rectangular cutout described above can be obtained.

In this way, the shape of the notch 6 is quite arbitrary.

In short, the shape of the tip of the inner glass tube 2 should be selected so that the discharge current can flow particularly easily at positions corresponding to the discharge paths divided into a plurality of strips.

FIG. 3 shows an inner glass tube 2 in place of the notch 6 mentioned above.
An example is shown in which a partition plate 12 is used to partition the opening at the tip into two parts.

In this case as well, the discharge current was easily shunted through the openings on both sides of the partition plate 12, and the same effect as the above-mentioned notch 6 was obtained.

Next, a notch 6 and a partition plate 1 are formed at the tip of the inner glass tube 2.
2, the wall of the outer glass bulb 1 facing the tip of the inner glass tube 2 is recessed inward in the shape of a partition plate to separate the discharge path. The same effect was obtained by using measures to make it easier.

The point is that the members regulating the discharge path near the tip of the inner glass tube (i.e., the wall surfaces of the inner glass tube and outer glass bulb) are more sensitive at positions corresponding to the respective branch discharge paths than at other positions. Any shape may be used as long as it facilitates the flow of discharge current.

As described above, according to the present invention, it is possible to obtain a small, bright discharge lamp that has substantially uniform and stable tube wall luminance over its entire circumference by using a small, single-cap bulb-shaped discharge bulb.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of a discharge lamp bulb according to an embodiment of the present invention, FIG. 2 is a diagram showing a modified example of the shape of the tip of the inner glass tube, and FIG. 3 is a diagram showing the tip of the inner glass tube. FIG. 4 is a diagram showing another modification of the shape, and FIG. 4 is a diagram showing an example in which a vertically elongated partition plate-shaped recess is provided on the top wall surface of the outer glass bulb. In the figure, 1... outer glass bulb, 2... inner glass tube, 4... cathode, 5... anode, 6... notch part.

Claims (1)

[Scope of Claims] 1. A sealed outer glass bulb, at least a rare gas sealed in the outer glass bulb, and an airtight tube disposed within the outer glass bulb substantially coaxially therewith, one end of which is open. an inner glass tube whose other end is closed; a single cathode disposed within the inner glass tube near the closed end; and an inner glass tube outside the inner glass tube and within the outer glass bulb. a plurality of anodes provided on the closed end side of the inner glass tube, a DC discharge is simultaneously generated between each of the plurality of anodes and the single cathode, and a discharge is generated at the open end of the inner glass tube. A low-pressure gas discharge lamp characterized in that a current is divided into a plurality of discharge paths corresponding to each of the plurality of anodes. 2. In the low-pressure gas discharge lamp according to claim 1, in order to maintain stable positions of the respective discharge paths separated at the open end of the inner glass tube, the open end of the inner glass tube Some of the walls of the inner glass tube and outer glass bulb that regulate the discharge path in the vicinity
A low-pressure gas discharge lamp characterized by having a shape that allows discharge current to flow more easily in parts corresponding to each branch discharge path than in other parts. 3. The low-pressure gas discharge lamp according to claim 1, characterized in that a notch is provided in the tube wall portion corresponding to each of the plurality of branch discharge paths at the open end of the inner glass tube. Low pressure gas discharge lamp. 4. The low-pressure gas discharge lamp according to claim 1, characterized in that a partition plate is provided at the open end of the inner glass tube to partition between each of the plurality of branch discharge paths. discharge lamp.