JPH065249A - Discharge lamp - Google Patents

Abstract

PURPOSE:To make it possible to grind without generating spots on the grinding surface, and to obtain an even plane light emission. CONSTITUTION:In a discharge lamp in which a phosphor 11 is spread on the inner surface of a glass bulb 1, both ends of the glass lamp are sealed airtight with metal caps 2 used as an electrode surface concurrently, and at the same time, a gas to contribute to the discharge is sealed, the electrode surface 20 of the metal cap 2 is provided close to the other end of the glass bulb 1 closer than the connection 26 with the bulb 1 and the outer position of the connection. Since the discharge surface 20 of the metal cap 2 is composed higher than the other positions, the removing work of an oxide membrane applied to the surface by the grinding can be carried out easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp used as a backlight for a viewfinder of a video camera, a liquid crystal display device of a liquid crystal television, and the like.

[0002]

2. Description of the Related Art As such a discharge lamp, there has been proposed a discharge lamp in which a flat tubular glass bulb is sealed at both ends with metal caps, and the metal caps are also used as electrode surfaces. Kaihei 3-210751). The discharge lamp has a metal cap (2) as shown in FIG.
A peripheral groove (24) is formed in the outer peripheral flange (23), and the end portion of the glass bulb (1) is fitted and sealed in the peripheral groove (24). Circumferential groove
Since the outer peripheral wall (25) of (24) and the discharge electrode surface (20) are almost at the same height, there are the following problems.

When the glass bulb (1) is sealed with the metal cap (2), an oxide film is formed on the metal cap (2) in order to increase the sealing strength, but the discharge electrode surface (20 ) Is a portion that contributes to discharge, and the oxide film on the surface of the electrode must be removed by polishing or the like, and then the glass bulb (1) must be sealed.

However, the metal cap (2) shown in FIG.
In this case, since the outer peripheral wall (25) of the peripheral groove (24) has substantially the same height as the discharge electrode surface (20), the polishing workability for removing the oxide film on the electrode surface is extremely poor. If the above polishing is insufficient, the discharge will be incomplete and uniform surface emission cannot be obtained. The present invention discloses a discharge lamp which can solve the above-mentioned problems.

[0005]

In the discharge lamp of the present invention, the inner surface of the glass bulb (1) is covered with a phosphor (11), and both ends of the bulb are hermetically sealed by a metal cap (2) which also serves as an electrode surface. In the discharge lamp in which the discharge contributing gas is sealed in the bulb (1), the electrode surface (20) of the metal cap (2) is joined to the bulb (1) at the joint (26) and outside of the joint. It is provided closer to the other end of the glass bulb (1) than the part.

[0006]

[Operation] Since the discharge electrode surface (20) is formed higher than other parts, polishing work becomes easy. Therefore, the polished surface can be polished without a spot, and uniform surface emission can be obtained.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a working state in which a flat glass bulb (1) is sealed with a metal cap (2) which is a feature of the present invention. The flat glass bulb (1) is formed of a soft glass such as soda glass or lead glass into a flat body and has both ends open. A phosphor (11) is applied to the inside of the glass bulb (1).

The metal cap (2) has a coefficient of expansion similar to that of the soft glass, 42% Ni-6Cr% -remainder F
Glass bulb (1) made of so-called 42-6 alloy of e
An outer peripheral wall (22) is integrally projectingly provided on the outer periphery of the flat plate portion which is slightly smaller than the opening. Above metal cap (2)
After applying the oxide film (21) on the entire surface,
0) The flat part and the peripheral wall (22) are polished in a range up to a position slightly above the joint (26) with the end face of the glass bulb (1),
The oxide film (21) is removed.

Glass bulb with metal cap (2)
The sealing of (1) is performed using the apparatus shown in FIG. The device is a bell jar mounted on a base (3) through a sealing material (41).
(4) is installed and the ceramic base (31) is installed in the bell jar (4).
Is provided. The ceramic base (31) has a concave portion (30) formed on the upper surface to which the metal cap (2) is fitted, and a high frequency induction heating coil (32) is mounted on the outer periphery.

The bell jar (4) is connected to a mercury storage chamber (42) through an opening / closing valve (43). The base (3) has a vacuum exhaust device (not shown) and a gas cylinder which communicate with the bell jar (4).
(36) is connected via the on-off valves (34) and (35), respectively.

The gas cylinder (36) is filled with discharge contributing gas such as argon gas having a purity of 99.99% or more or a slight amount of auxiliary gas mixed therein such as argon gas.

Then, the metal cap (2) is set in the recess (30) of the ceramic base (31) with its discharge electrode surface (20) facing upward, and the upper end of the metal cap (2) is previously placed on the metal cap (2). Place the glass bulb (1) sealed with the cap (2a).

Open the on-off valve (34) leading to the vacuum exhaust device,
The inside of the bell jar (4) is 2 × 10 ^-3 ~ by the vacuum exhaust device.
Exhaust to about 2 × 10 ^-7 Toor.

The on-off valve (34) of the vacuum exhaust device is closed, the on-off valve (35) communicating with the gas cylinder (36) is opened to fill the bell jar (4) with 10 to 120 Toor of discharge contributing gas, and the mercury storage chamber.
The on-off valve (43) leading to (42) is opened and a required amount of mercury pool is dropped into the bell jar (4). The atmosphere inside the glass bulb (1) is almost the same as that inside the bell jar (4) through the gap with the metal cap (2).

After that, when the high frequency induction coil (32) is energized and the lower ends of the metal cap (2) and the glass bulb (1) are heated, the glass in contact with the metal cap (2) is melted and both of them are melted. Can be joined. In the discharge lamp thus completed, the metal cap (2) has the glass bulb (1).
The discharge electrode surface (20) is also used as a sealing member for the end opening of the glass bulb, and a part of the metal cap (2) is a glass bulb (2).
Since it is exposed to the outside of the lamp, the lighting circuit and the metal cap (2) can be easily connected by soldering without providing a lead piece, which is effective for man-hours for electrical connection and labor saving of parts. .

As in the above-mentioned embodiment, the glass bulb end is melted only by heat without any intervention between the glass bulb (1) and the metal cap (2), and the metal cap (2) and the glass cap are joined. There are a method of bringing them into close contact and a method of interposing frit glass between the end face of the glass bulb (1) and the metal cap (2).

The former requires the glass bulb (1) and the metal cap (2) to be heated above the softening point of the glass (soda glass about 900 ° C., lead glass about 850 ° C.), so the heating energy is higher than that of the latter. It's big, but the work is simple.

In the latter case, frit glass is applied to the end of the metal cap (2) or the glass bulb (1) or both of them in advance, and then calcined. It can be done by raising the temperature to about 470 ℃.

Frit glass is applied to the end of the metal cap (2) or the glass bulb (1) or both,
Although it takes time to calcine, the heating energy is less than that of the former, the effect of strain due to heat is negligible, and the quality of the product is stable, so it is widely used industrially.

In any case, the surface of the metal cap (2) is treated with an oxide film in order to enhance the sealing strength with the glass bulb (1). The metal oxide film (21) on the discharge electrode surface (20) of the existing metal cap (2) is arranged as a pair of electrodes with the metal oxide film (21) removed in advance by means such as polishing.

In carrying out the polishing work for creating the discharge electrode surface (20), FIGS. 3a, 3b, 4a, 4b, 5
a and b (both are a sectional view of the metal cap (2), b
Is a perspective view), the periphery of the metal cap (2),
That is, by making the discharge electrode surface (20) (polishing surface) higher than the joint portion (26) (sealing portion) with the glass bulb (1), the polishing of the portion can be facilitated. Is a feature of.

3 to 5 show a metal bulb (2) applied to the inner surface of the end of the glass bulb (1) for sealing, and FIG. 3 shows the discharge electrode surface (20) as a flat surface, and FIG. Is the discharge electrode surface
FIG. 5 shows an embodiment in which (20) is a curved surface, and FIG. 5 is a discharge electrode surface (20) having an acute angle portion.

In FIG. 6, a peripheral groove (24) is formed on a flange (23) projecting from the outer periphery of the metal cap (2), and the end portion of the glass bulb (1) is formed into the peripheral groove (24). It is fitted and sealed. Also in the case of FIG. 6, the height of the outer peripheral wall (25) of the peripheral groove (24) is formed lower than the electrode surface of the metal cap (2). In this case, since the end face of the glass bulb (1) is brought into contact with the groove bottom for sealing, the glass bulb (1) is not easily affected by the deformation of the end portion of the glass bulb (1) during sealing.

FIG. 7 shows a method of manufacturing the flat glass bulb (1) used in the discharge lamp. Horizontal sealed enclosure
A glass circular tube (10) which is a material for the flat glass bulb (1) by penetrating the upper ends of both ends in (5) and inserting the supporting shaft (51) horizontally.
Is hung on the support shaft (51) and set in the housing (5). Case
Longitudinal hole (50) and glass tube (1)
Insert the weight round bar (52) into 0).

Hot air is blown into the housing from the air supply port (53) provided on the upper surface of the housing (5) and is discharged from the exhaust port (54) provided on the lower surface of the housing (5). Hot air is blown into the glass circular tube (10) from the air supply port (55) provided at one end of the glass, and is exhausted from the exhaust port (56) provided at the other end of the glass circular tube (10) from the inside and outside surfaces. Heat to the softening temperature of the glass.

As the glass circular tube (10) of FIG. 8a softens, the weight round bar (52) descends by its own weight, and the glass circular tube (10) is stretched to a flat body as shown in FIG. 8b. When it is observed that the glass circular tube (10) has been stretched to the molding size, the pressure of the hot air sent from the air inlet is adjusted to adjust the cross-sectional shape of the flat tubular glass.

After the glass circular tube is formed into a desired flat cylindrical body, the temperature of the hot air is gradually lowered, and when the temperature becomes lower than the strain point (500 ° C.) of the glass, the flat glass tube is sealed into a closed casing (5 ). Glass bulb molded by the above method (2)
Since it does not come into contact with other objects except for the contact parts with the support shaft (51) and the weight round bar (52), the surface pattern of the mold has a glass surface like the case of molding a glass bulb. Is not transferred to the glass bulb, polishing after molding is not necessary, and a glass bulb with high surface accuracy can be obtained. The present invention is not limited to the configuration of the above embodiment, and various modifications can be made within the scope of the claims.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a method of joining metal caps.

FIG. 2 is a perspective view of a glass bulb and a metal cap.

FIG. 3 is an end view and a perspective view of the first embodiment of the metal cap.

FIG. 4 is a sectional view and a perspective view of a second embodiment of the metal cap.

FIG. 5 is a sectional view and a perspective view of a third embodiment of a metal cap.

FIG. 6 is a sectional view of a fourth embodiment of the metal cap.

FIG. 7 is a perspective view of an apparatus for stretching a glass cylinder into a flat body.

FIG. 8 is a cross-sectional view of a glass cylinder and a stretched state of the cylinder.

FIG. 9 is an end view of a conventional metal cap.

[Explanation of symbols] (1) Glass bulb (2) Metal cap (20) Discharge electrode surface (26) Joint

Claims (1)

[Claims] 1. A metal cap (2) which covers the inner surface of a glass bulb (1) with a phosphor (11) and also serves as a discharge electrode surface (20).
In the discharge lamp in which both ends of the bulb are hermetically sealed by the above, and the discharge contributing gas is sealed in the bulb (1), the discharge electrode surface (20) of the metal cap (2) is attached to the bulb.
A discharge lamp characterized in that it is provided closer to the other end of the glass bulb (1) than the junction (26) with (1) and the outside of the junction.