KR930000391B1 - Hot-cathode type low pressure rare gas discharge lamp - Google Patents

Abstract

No content.

Description

[Name of invention]

Hot cathode type low pressure rare gas discharge lamp

[Brief Description of Drawings]

1 is a front view in which a part of a hot cathode type low pressure rare gas discharge lamp according to an embodiment of the present invention is cut out.

2 is a characteristic diagram showing a luminance distribution of a mercury-encapsulated lamp.

3 is a characteristic diagram showing a lamp luminance distribution in the present invention.

4 is a characteristic diagram showing the relationship between filament temperature and lamp life.

5 is a characteristic diagram showing a lamp luminance distribution in the case of DC lighting.

Detailed description of the invention

[Technical Field]

The present invention relates to a hot cathode type low pressure rare gas discharge lamp having an electrode which operates as a hot cathode while at least one electrode is in operation.

[Background]

It is strongly requested that the discharge lamp used as the light source for the OA device be uniform in brightness over its entire length.

As a prior art relating to the improvement of the luminance distribution, for example, Japanese Patent Application Laid-Open No. 57 (1982) -11465 discloses an electrode filament coil incandescent, which causes an end of a discharge lamp that is particularly susceptible to luminance degradation. Compensating for the luminance of is disclosed.

However, in the prior art, it is necessary to heat the low filament until a color temperature of 2600 ° K to 3200 ° K, and as a lifespan for maintaining the discharge under the heating conditions, unless another pair of filament coils are disposed Therefore, there is a problem that the number of parts of the electrode structure increases, the electrode structure becomes very complicated, resulting in complicated lamp manufacturing and cost increase.

[Initiation of invention]

According to the present invention, it is possible to obtain a luminance distribution that is practically practical as a light source for an OA device over the entire length of the discharge lamp while preventing the shortening of the lifetime of the so-called conventional electrode structure without complicating the electrode structure. It is an object of the present invention to obtain a hot cathode type low pressure rare gas discharge lamp capable of improving the luminance distribution characteristic.

In order to achieve the above object, the hot cathode type low pressure rare gas discharge lamp according to the present invention is characterized in that at least one electrode has a temperature of 800 ° C. or more and 1200 ° C. or less in an electrode disposed at both ends of the glass bulb.

In the hot cathode type low pressure rare gas discharge lamp of the present invention, at least one of the electrodes is heated to 800 ° C. or more during its lighting, so that unlike the general discharge lamp in which the water temperature is enclosed, the electrodes between the two ends of the glass bulb become a preferable discharge state. Moreover, since the upper limit of the said heating temperature is regulated below 1200 degreeC, shortening of a lamp life is certainly prevented beforehand. The effect on the improvement characteristics and lifetime of the luminance distribution is confirmed by experimental data.

Best Mode for Carrying Out the Invention

In FIG. 1, which partially shows a hot cathode type low pressure rare gas discharge lamp having an aperture opening according to the present invention, (1) is a glass bulb having an outer diameter of 15.4 mm and a thickness of 0.7 mm. The reflection film 2 is formed on the inner circumferential surface thereof.

Phosphor layer 3 is coated and formed on the reflective film 2, and the phosphor layer 3 is made of GP ₁ G ₁ green phosphor manufactured by Kasei Optronics.

Upper 2 mm in width in which the phosphor layer 3 and the reflecting film 2 are not coated and bonded to a common position along the longitudinal direction of the glass bump 1 of the phosphor layer 3 and the reflecting film 2. A tour opening 8 is formed, and the aperture opening 8 is exposed on the surface of the glass bulb 1.

A pair of left and right electrodes 4 (only one electrode 4 is shown in FIG. 1) is disposed inside both ends of the glass bulb 1.

The electrode 4 has a pair of lead wires 6 disposed on a stem 5 which closes the end portion of the glass bulb 1 in an airtight manner, and the wires are connected to these lead wires 6. It consists of a tungsten filament coil 7 lined.

The filament coil 7 is a so-called triple coil wound in triplicates, and an electromagnetic radiation substance is coated thereon.

Here, the distance between the electrodes 4 at both ends of the glass bulb 1 is set to 260 mm.

In the glass bulb 1, a mixed gas of Xe 10% and Ne 90% is sealed at a sealing pressure of 3 Torr.

In addition, in both ends of the glass bulb 1, a getter 9 for adsorbing impurity gas during its lifetime is disposed as shown in FIG. 1 only at one end.

The low pressure rare gas discharge lamp according to the embodiment of the present invention is configured as described above, and the lamp is hot-cathode started using a sinusoidal wave power source of 40 KHz.

In addition, the luminance characteristics of the low pressure rare gas discharge lamp was investigated by experiment.

In this experiment, the low pressure rare gas discharge lamps and the mercury-sealed discharge lamps (hereinafter referred to as mercury-sealed lamps) were manufactured separately and their luminance characteristics were compared.

2 shows the luminance distribution of the mercury-encapsulated lamp, and its luminance value is represented by a relative value with a central luminance of 100.

As is apparent from FIG. 2, in the case of the mercury-sealed lamp, the luminance is rapidly decreased from the vicinity of the center of the glass bulb 1 of the electrode 4 toward the end of the glass bulb 1, but the glass bulb ( 1) A uniform luminance distribution is formed throughout the central part. Although not particularly shown, this tendency is not changed even if the filament coil 7 of the electrode 4 is heated to 800 ° C or higher, even if it is not heated at all.

FIG. 3 shows the luminance distribution of the low pressure rare gas discharge lamp according to the embodiment of the present invention, and the luminance value is expressed in relative values with the central luminance of 100 as in FIG. In Fig. 3, the luminance distribution in the case where the filament coil of the electrode 4 is heated to 800 ° C is indicated by a solid line, while the case where the heating is performed at 500 ° C is indicated by a dotted line, and the case where no heating is performed is indicated by a dashed line. Indicated. All of these luminance distributions cause a sudden decrease in luminance from the electrode 4 toward the end side of the glass bulb 1, and show the same tendency as in the case of the mercury-sealed lamp shown in FIG. However, in FIG. 3, the luminance distribution of the wave form becomes the maximum wave height in the vicinity of the electrode 4 and gradually attenuates from the electrode 4 toward the center side of the glass bulb 1. Indicates. Therefore, there is a large difference in the distribution characteristics of both in the luminance distribution of the mercury-encapsulated lamp shown in FIG. 2 and the luminance distribution of the low pressure rare gas discharge lamp shown in FIG. Incidentally, in the wave shape luminance distribution in FIG. 3, the difference in wave height decreases as the filament temperature increases. Here, if the width of the section including the central portion of the glass bulb 1 and the luminance decreases by 20% for the first time than the luminance of the central portion is referred to as the effective width, the effective width of the filament temperature of the electrode 4 at 800 ° C or more is greater than that of the filament. Furthermore, the section widens to both pipe ends (both ends of the glass bulb 1). On the other hand, when the filament temperature is less than 800 ° C, the effective width becomes smaller than the distance between the positive electrodes 4, resulting in practical problems.

Therefore, it is apparent that the luminance distribution is improved when the filament coil of the electrode 4 is heated to 800 ° C or higher. However, when the heating temperature of the filament coil is more than 1200 ℃ evaporation of the electron-emitting material is remarkable, life is shortened.

Based on the results of these various experiments, in the present invention, the heating temperature range is set so that the electrode in the lamp is heated to a temperature range of 800 ° C or more and 1200 ° C or less, which is the maximum feature of the present invention. to be.

)이 될때까지의 실점등시간으로 수명을 파악하였다. 이 결과로부터도 명백한 바와 같이, 필라멘트가 1200℃를 초과하면 수명이 단축된다고 하는 문제가 발생하여 바람직하지 않다는 것이 명백하였다.4 shows the relationship between the filament temperature and the life of the electrode according to the above test results. In this case, the filament of the electrode should always be heated, and the lamp is turned on by a 2-minute flashing cycle of 1 minute on and 1 minute off, and the lamp is turned on.

The life time was determined by the time of the lighting. As is also apparent from these results, it was apparent that the problem of shortening the life occurred when the filament exceeded 1200 ° C, which was not preferable.

In the above embodiments, the lifespan in relation to the luminance distribution and the filament temperature when the low pressure rare gas discharge lamp is switched on at 40 KHz is described. The inventors of the present application confirm.

5 shows measurement results of luminance distribution in the case where the low pressure rare gas discharge lamp of the above embodiment is used in a DC circuit having a tube voltage of 80V. In this case, both ends of one electrode filament were short-circuited and used as an anode without heating. In addition, the other electrode filament was used as a cathode, and the luminance distribution was measured at 540 占 폚 and 800 占 폚 as in the case of the above-described embodiment.

As is apparent from this measurement result, even in the case of DC lighting, the unevenness of the luminance distribution at the end of the tube during the lamp operation depends on the electrode temperature and when the electrode is operating as a cathode, the electrode and the positive pole It corresponds to the some dark part which arises between and.

The phenomenon was the same even if a filament was not used as the anode and a simple electron-accommodating means without a heating means such as a tungsten rod generally used for a cold cathode or the like was used.

Since the effect of improving the brightness distribution is recognized by setting the filament temperature to 800 ° C. or higher during lamp lighting, the improved brightness distribution can be obtained immediately after starting the lamp by heating the filament temperature to 800 ° C. or higher in the state before lamp startup. have. In addition, since the present invention aims to obtain a discharge lamp suitable as a light source for an OA device, it can be said that the mercury-sealed lamp described in FIG. 2 is also effective in terms of luminance distribution characteristics.

However, in the case of the mercury-sealed lamp, there are other problems such as a slow rise (starting up) and a tendency to be affected by the ambient temperature.

In addition, although the filament coil was used as the electrode 4 in the said embodiment, the same effect can be expected also in a heat dissipation type or sinter type electrode etc. which do not use a filament coil.

[Industry availability]

As described above, the hot cathode type low pressure rare gas discharge lamp according to the present invention is designed to heat the electrode temperature in the range of 800 ° C. to 1200 ° C. during the lamp lighting. Since the characteristic can be improved, it is suitable as a light emitting light source for OA devices.

Claims (1)

A rare gas is sealed, and the light emitted by the rare gas is converted into a desired visible light by a phosphor, and a first electrode disposed at one end of the glass bulb and a second electrode disposed at the other end of the glass bulb. And a first electrode each operating as a cathode during operation of the discharge lamp, each of the filaments being heated to a temperature of at least 800 ° C. and not more than 1200 ° C. when at least one of the first and second electrodes is started as a hot cathode while being lit. And a second electrode comprising a hot cathode type low pressure noble gas discharge lamp.

Images