JPH10302718A - Low pressure mercury discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the start-up of luminous flux at an early stage of lighting of a sealed-instrument-type and high-load-type low pressure mercury discharge lamp, particularly, bulb type fluorescent lamp or compact type fluorescent lamp. SOLUTION: This low pressure mercury discharge lamp has a container member 2 having an opening at a discharge space 9 inside an emitting tube, a gap opening/closing member 3 composed of a material having a higher thermal expansion coefficient than that of the material for the container member, a mercury sealing container 1 composed of mercury source 4 having the equal mercury vapor pressure to pure mercury. When a lamp is off, the gap between the container member 2 and the gap opening/closing member 3 becomes wide enough for mercury vapor to move diffusely from the mercury source 4 to a discharge space 9. When the lamp is on, the gap opening/closing member 3 chokes the opening by means of thermal expansion as the temperature of emitting tube rises, in order to prevent the diffusion move of mercury from the mercury source 4 to the discharge space 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact fluorescent lamp, such as a bulb-type fluorescent lamp, which is lighted under a high load, and a fluorescent lamp which is frequently used under high-temperature conditions, such as in a sealed fixture. .

[0002]

2. Description of the Related Art Among fluorescent lamps mainly used for low-pressure mercury discharge lamps, a bulb-shaped fluorescent lamp is formed by bending an arc tube provided with electrodes at both ends into, for example, a U-shape to resemble an incandescent lamp. It is stored inside a glove-shaped cover. Therefore, when the lamp is turned on, the temperature of the arc tube inside the glove rises too much, and the mercury vapor pressure also rises, greatly exceeding the optimal amount of mercury, and as a result, the lamp luminous flux significantly decreases. There is a problem of inviting.

In order to solve such a problem, for example, as disclosed in JP-A-62-64044, the mercury vapor pressure in the discharge space inside the arc tube is controlled by using amalgam. I have. The configuration of this conventional example will be described with reference to FIG.

As shown in FIG. 5, the main amalgam 10 comprises
The bulb 5 is housed together with a positioning glass rod 12 and the like in a thin tube 7 provided near one of the pair of electrodes 6 at both ends of the bulb 5. The auxiliary amalgam 11 is provided near the electrode 6 such that the entire surface area is directly exposed to the discharge space 9. The mercury vapor pressure during stable lighting is controlled by the main amalgam 10, and the auxiliary amalgam 11 facilitates the release of mercury into the discharge space 9 at the beginning of lighting.
Due to these effects, it is configured such that a constant brightness is secured from the initial lighting to the stable lighting.

Further, since the mercury vapor pressure of the auxiliary amalgam 11 is designed to be lower than that of the main amalgam 10, the auxiliary amalgam 11 adsorbs mercury atoms from the main amalgam 10 after the lamp is turned off.

In the above conventional example, a copper ballast circuit with a built-in glow tube is mainly used for the lighting circuit. In this case, the auxiliary amalgam 11 was heated by the preheating of the electrode 6 during the operation of the glow tube in the early stage of lighting, and the heat released mercury. Therefore, the mercury vapor pressure increased mainly in the vicinity of the auxiliary amalgam 11. Therefore, in the conventional bulb-type fluorescent lamp, a desired luminous flux can be obtained by the time when the glow tube is operated and turned on after the lamp is started, and the subsequent rise of the luminous flux can be improved. On the other hand, when a glow tube built-in type copper ballast circuit is used, the lamp is not turned on until the glow tube has been operated.

Further, as disclosed in Japanese Patent Application Laid-Open No. 60-154451, amalgam is accommodated in a container having a small hole having an opening area of 0.1 [mm ² ] or less, and auxiliary amalgam is used. Instead, a configuration in which the light flux rising time at the time of relighting is shortened has been proposed.

[0008]

In recent years, there has been a demand for a light bulb-type fluorescent lamp to be turned on more instantaneously. In place of the conventional copper ballast circuit with a built-in glow tube, an instant start-up type fluorescent lamp has been demanded. Electronic ballast circuits have been increasingly used.

However, when an instant-start type electronic ballast circuit is used in a conventional bulb-type fluorescent lamp, the preheating time of the electrodes is too short to sufficiently heat the auxiliary amalgam. Therefore, the amount of mercury atoms released from the auxiliary amalgam in the initial stage of lighting is small, and it is difficult to maintain the mercury vapor pressure in the initial stage of lighting at or above a certain level. As a result, when an instant-start type electronic ballast is used for a bulb-type fluorescent lamp, it can be turned on instantaneously, but has a problem in that the time from the start of lighting to reaching a certain luminous flux becomes longer. .

The present invention has been made in order to solve such a problem, and it is an object of the present invention to provide a low-pressure mercury discharge lamp which is bright from the start of lighting and can maintain a certain brightness or more during lighting. It is an object.

[0011]

A low-pressure mercury discharge lamp according to the present invention has a container member having an opening in a discharge space inside an arc tube and a coefficient of thermal expansion larger than the coefficient of thermal expansion of the material of the container member. A low-pressure mercury discharge lamp having a mercury-filled container including a gap opening / closing member made of a material and a mercury source housed in a space formed by the container member and the gap opening / closing member, wherein the container member and the gap The gap with the opening / closing member is a distance at which the diffusion and movement of mercury vapor from the mercury source into the discharge space can be performed at room temperature.However, when the lamp is turned on, the gap is closed by thermal expansion of the gap opening / closing member. Diffusion movement of mercury vapor from the mercury source into the discharge space is prevented (claim 1).

The low-pressure mercury discharge lamp of the present invention uses a material exhibiting a mercury vapor pressure as high as that of pure mercury without using a conventional method using a main amalgam and an auxiliary amalgam.
It is sealed in a container that opens and closes according to the temperature difference between when the lamp is turned on and when it is turned off, and controls the mercury vapor pressure in the arc tube.

That is, when the lamp is turned off when the temperature of the mercury source is at room temperature, the mercury vapor pressure in the discharge space is almost equal to the mercury vapor pressure of pure mercury. In the stable lighting state, the gap is closed due to the difference in the thermal expansion coefficient between the container member of the mercury-filled container and the gap opening / closing member, so that the mercury vapor cannot move from the mercury source into the discharge space. It is possible to maintain a high luminous flux without the pressure significantly exceeding the appropriate value.

Here, the mercury-filled container has a substantially cylindrical container member having one end closed, and a substantially bar-shaped outer peripheral surface having substantially the same shape as the inner peripheral surface of the container member inserted into the container member. It is preferable to include a gap opening / closing member and a mercury source accommodated in the bottom of the container member.

According to this structure, the contact area between the container member and the gap opening / closing member can be increased, so that
By obtaining a sufficient closing property at the time of lamp lighting, by adjusting the insertion length of the gap opening / closing member into the container member,
Adjusting the diffusion rate of mercury vapor from the mercury source to the discharge space,
The temperature of the mercury source can be adjusted. Further, the production of the mercury-filled container is easy.

In the mercury-filled container, the container member has a substantially cylindrical shape, the gap opening / closing member has a substantially cylindrical shape, the inner diameter of the container member is about 1.5 to 3 [mm], The gap with the member is about 4 [μm] or less at room temperature,
It is preferable that a difference between a coefficient of thermal expansion of the material of the gap opening / closing member and a coefficient of thermal expansion of the material of the container member is about 1 × 10 ⁻⁶ [1 / ° C.] or more (claim 3).

According to this structure, the mercury-sealed container can be manufactured by press-fitting the gap opening / closing member into the container member, and the mercury-sealed container can be housed in the narrow tube at the end of the arc tube. . Further, by combining the above numerical values, the mercury-filled container can be reliably closed due to the temperature difference between the coldest point when the normal bulb-type fluorescent lamp is turned off and when it is turned on.

Further, in the mercury-filled container, the container member and the gap opening / closing member are made of a material that does not form amalgam with mercury or a material that does not react with mercury. There is no consumption of mercury and no deterioration of the luminous flux rising characteristics at the time of lighting.

The low-pressure mercury discharge lamp of the present invention has a pair of electrodes inside the arc tube (Claim 5) and an electromagnetic induction coil provided outside the arc tube. The present invention is also applicable to an electrodeless discharge lamp that supplies high-frequency power to the inside of the arc tube.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A low-pressure mercury discharge lamp according to the present invention will be described below with reference to FIGS.

FIG. 1 is a partially cut-away side view of an arc tube of a bulb-type fluorescent lamp which is an embodiment of the low-pressure mercury discharge lamp of the present invention, and FIG. 2 is an enlarged cross-sectional view of an end portion of the arc tube. .

As shown in FIG. 1, the arc tube comprises a bulb 5 bent in a U-shape and a pair of electrodes 6 provided at both ends thereof.
And a thin tube 7, and a fluorescent substance 8 is provided on the inner surface of the bulb 5.
Is attached. The discharge space 9 inside the bulb 5 is filled with an appropriate amount of a rare gas such as argon and is in spatial communication with the thin tube 7.

As shown in FIG. 2, a mercury-filled container 1 containing a mercury source 4 is accommodated inside a thin tube 7.
The opening of the mercury-filled container 1 is located on the side of the discharge space 9,
The mercury source 4 is located near the coldest point at the tip of the thin tube 7.

The thus configured lamp is turned on by supplying power from the electrode 6 into the bulb 5.

Next, details of the mercury enclosure 1 will be described. As shown in FIG. 3, the mercury-filled container 1 includes a substantially cylindrical container member 2 having one end closed, a substantially columnar gap opening / closing member 3 inserted from an opening of the container member 2, and a container member 2. And a mercury source 4 housed in the space at the bottom of the container member 2 formed by the gap opening and closing member 3.

An example of the size of the mercury enclosure 1 is as follows.
The inner diameter of the container member 2 and the outer diameter of the gap opening / closing member 3 are about 2
[Mm], the height of the container 1 is about 12 [mm], which is a size that can be accommodated in the thin tube 7. Further, the gap between the container member 2 and the gap opening / closing member 3 is a perfect circle, and
The radial gap is about 4 [μm], assuming that they are coaxially arranged. If the gap is at this level, the gap opening / closing member 3 can be closed by thermal expansion when the lamp is turned on, and the production of the mercury-filled container 1 is performed by press-fitting the gap opening / closing member 3 into the container member 2. Is possible.

The mercury source 4 is a spherical alloy of zinc and mercury having a weight of about 14 [mg] and a diameter of about 1 [mm], and has a mercury ratio of about 50 [% by weight]. This alloy has a mercury vapor pressure equivalent to that of pure mercury and is solid at room temperature, so that the amount of mercury can be easily adjusted and handled.

The material of the container member 2 is an alloy having a ratio of nickel to iron of about 1: 1. The material of the gap opening / closing member 3 is copper. Since both materials are hard to form amalgam with mercury, they do not cause consumption of mercury or deterioration of the light flux rising characteristic at the time of lighting.

Next, the operation principle of the low-pressure mercury discharge lamp of the present invention will be described. When the lamp is turned off, that is, when the temperature of the arc tube is room temperature, the gap between the container member 2 and the gap opening / closing member 3 is open to the extent that mercury vapor can diffuse and move to the discharge space 9. Mercury vapor released from the mercury source 4 inside the mercury enclosure 1 diffuses and moves to the discharge space 9 to be in an equilibrium state. At this time, the mercury vapor pressure in the discharge space 9 is substantially equal to the mercury vapor pressure when pure mercury is used, so that the initial luminous flux at the time of starting the lamp becomes high.

When the lamp is lit in a sealed fixture or lit with a high load, the temperature of the arc tube rises excessively as compared with a normal lighting state. In this case, the container member 2
Since the gap opening / closing member 3 having a larger coefficient of thermal expansion closes the gap with the container member 2 by thermal expansion, the mercury vapor released from the mercury source 4 inside the mercury container 1 The mercury vapor pressure in the discharge space 9 can be maintained at an appropriate value.

A specific example of the difference in the coefficient of thermal expansion between the container member 2 and the gap opening / closing member 3 will be described below. As described above, in the cylindrical mercury-filled container 1, the inner diameter of the container member 2 is about 2 [mm].
As described above, when the gap between the container member 2 and the gap opening / closing member 3 at room temperature is about 4 [μm] or less, it is sufficient if the difference in thermal expansion coefficient between both is about 1 × 10 ⁻⁶ [1 / ° C.] or more. It is.

That is, in the case of a general bulb-type fluorescent lamp, the temperature difference between the coldest point (near the tip of the thin tube 7 where the mercury source 4 is located) when the lamp is turned on and when it is turned off is usually about 80.
[° C.] or more, the difference in thermal expansion coefficient is about 1 × 10 ⁻⁶ [1
/ ° C] or more, the gap with the container member 2 is closed due to thermal expansion of the gap opening / closing member 3 when the lamp is turned on. As described above, when the container member 2 is an alloy in which the ratio of nickel to iron is about 1: 1 and the material of the gap opening / closing member 3 is copper,
The difference in thermal expansion coefficient is about 1 × 10 ⁻⁵ [1 / ° C.], and the gap can be reliably closed when the lamp is turned on.

Similarly, the inner diameter of the container member 2 is about 2 [mm].
The container member 2 and the gap opening / closing member 3 at room temperature
Is less than about 4 [μm], if the temperature difference between the coldest point when the lamp is turned on and when the lamp is turned off is about 15 ° C. or more, the thermal expansion between the container member 2 and the gap opening / closing member 3 When the rate difference is about 2 × 10 ⁻⁵ [1 / ° C.] or more, the gap between the container member 2 and the gap opening / closing member 3 is closed when the lamp is turned on.

In the case where the gap between the container member 2 and the gap opening / closing member 3 is the same, the higher the inner diameter of the container member 2 is, the higher the closing property is obtained. Therefore, the inner diameter of the container member 2 is about 2 [mm] or more. However, if it is about 1.5 [mm] or more, practically necessary obstruction can be obtained. On the other hand, if it is too large, it becomes difficult to accommodate the container in the thin tube 7, so the inner diameter of the container member 2 is preferably about 3 [mm] or less.

The gap between the container member 2 and the gap opening / closing member 3 may theoretically be larger than mercury atoms. However, the ease of passage of mercury vapor (conductance) and the ease of manufacture are taken into consideration. Should be large enough. However, if it exceeds about 4 [μm], it is necessary to increase the size of the container member 2 or increase the difference in thermal expansion coefficient.
There are problems that the size and cost of the mercury-filled container are increased, and that there is less room for material selection.

The material of the container member 2 and the gap opening / closing member 3 may be glass, ceramic, a heat-resistant polymer compound or the like that does not react with mercury, or gold, silver, copper, platinum, aluminum, magnesium, nickel, A metal such as iron, titanium, and manganese, which hardly forms amalgam, or an alloy thereof may be used. From these, a combination having a necessary difference in the coefficient of thermal expansion can be appropriately selected.

As the mercury source 4, an alloy of mercury and zinc is used in the above embodiment, but any other material having a mercury vapor pressure as high as that of pure mercury may be used. May be used.

The shape of the mercury container 1 is not limited to a cylinder.
It may be a square pole or the like. For example, when the shape of the container member 2 is a cylinder, the shape of the gap opening / closing member 3 is preferably a column, or one or two or more spheres. When the shape of the container member 2 is a square tube, Preferably, the gap opening / closing member 3 is a quadrangular prism.

The low-pressure mercury discharge lamp is not limited to a bulb-shaped fluorescent lamp bent in a U-shape. If it is used in a high-temperature environment and an excessive rise in mercury vapor pressure is a problem, a straight tube fluorescent lamp is used. Similar effects can be obtained with lamps and round tube fluorescent lamps.

Further, the present invention is not limited to the electrode type fluorescent lamp having a pair of electrodes in the arc tube as in the above-described embodiment, but also includes the electromagnetic induction coil 13 provided outside as shown in FIG. An electrodeless discharge lamp that supplies high-frequency power to the inside of the lamp by the electromagnetic induction described above may be used.

[0041]

As described above, according to the present invention, the rising of the luminous flux at the time of starting the lamp, which is a problem in the electronic ballast type fluorescent lamp of the instant start type using amalgam, is improved, and the temperature of the lamp becomes high. It is possible to maintain a high luminous flux in such a lamp lighting state,
A low-pressure mercury discharge lamp is provided.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing one embodiment of a low-pressure mercury discharge lamp of the present invention.

FIG. 2 is an enlarged sectional view of the end portion of the arc tube.

FIG. 3 is an enlarged sectional view of the same mercury-filled container.

FIG. 4 is a partially cutaway side view showing a different embodiment of the low-pressure mercury discharge lamp of the present invention.

FIG. 5 is a partially cutaway side view showing a conventional low-pressure mercury discharge lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mercury enclosure 2 Container member 3 Gap opening / closing member 4 Mercury source 5 Bulb 6 Electrode 7 Narrow tube 8 Phosphor 9 Discharge space 13 Coil

Claims (6)

[Claims] 1. A container member having an opening in a discharge space inside an arc tube, a gap opening / closing member made of a material having a coefficient of thermal expansion larger than a coefficient of thermal expansion of a material of the container member, A low-pressure mercury discharge lamp having a mercury-enclosed container including a mercury source housed in a space formed by a gap opening / closing member, wherein a gap between the container member and the gap opening / closing member is the mercury source at room temperature. Is the distance at which mercury vapor can diffuse and move into the discharge space, but when the lamp is turned on,
A low-pressure mercury discharge lamp, which is closed by thermal expansion of the gap opening / closing member and prevents diffusion movement of mercury vapor from the mercury source into the discharge space. 2. The container according to claim 1, wherein the mercury-filled container has a substantially cylindrical container member having one end closed and an outer peripheral surface having substantially the same shape as an inner peripheral surface of the container member inserted into the container member. 2. The low-pressure mercury discharge lamp according to claim 1, comprising a gap opening / closing member and a mercury source housed at a bottom of the container member. 3. The mercury-filled container, wherein the container member has a substantially cylindrical shape, the gap opening / closing member has a substantially cylindrical shape, an inner diameter of the container member is approximately 1.5 to 3 [mm], and When the gap with the gap opening / closing member is about 4 [μm] or less, the difference between the coefficient of thermal expansion of the material of the gap opening / closing member and the coefficient of thermal expansion of the material of the container member is about 1 × 10 ⁻⁶ [1 / ° C. The low-pressure mercury discharge lamp according to claim 2, wherein: 4. The mercury-filled container according to claim 1, wherein the container member and the gap opening / closing member are made of a material that does not form amalgam with mercury or a material that has no reactivity with mercury. 4. The low-pressure mercury discharge lamp according to any one of 3. 5. The low-pressure mercury discharge lamp according to claim 1, further comprising a pair of electrodes inside said arc tube. 6. An electrodeless discharge lamp for supplying high-frequency power into an arc tube by electromagnetic induction from an electromagnetic induction coil provided outside the arc tube. A low-pressure mercury discharge lamp according to any one of the above.