JPS5838447A - Neon gas discharge lamp for optical device - Google Patents

Abstract

PURPOSE:To secure a high-efficient light source available for an optical device, by setting the outer diameter of a glass tube to the specified size and sealing up neon into the glass tube at a specified pressure value. CONSTITUTION:A neon gas excellent in luminous efficacy for visible rays is sealed up into a glass tube for example of more than 20mm. in outer diameter and 436mm. in length, in which a filament coil electrode holding thermionic radiant substances at a pressure of more than 1 torr is sealed. With this, a neon gas discharge lamp for an optical device can be secured, which can exhibit high- efficiency at a rated lamp current of more than 0.2A.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a neon gas discharge lamp used in an optical device.

Incandescent lamps and fluorescent lamps are generally used as lamps for optical devices such as electronic copying machines, facsimiles, and optical character readers. However, incandescent light bulbs have problems with poor efficiency and longevity.

Fluorescent lamps, on the other hand, have better efficiency and longevity.

Its properties depend on mercury vapor pressure and are therefore greatly affected by temperature. In other words, the amount of light changes depending on the ambient temperature, and the amount of light changes considerably after two lightings until the mercury vapor pressure stabilizes. Furthermore, the light intensity of fluorescent lamps decreases significantly during their lifetime due to deterioration of the fluorescent material and other factors. These points are major drawbacks for the above-mentioned optical device.

This invention has improved the above drawbacks. The object is to provide an efficient light source for an optical device.

The inventors first came up with the idea of using a low-pressure rare gas discharge lamp filled with neon, which has the highest visible light emission efficiency among rare gases, as the light source.

Compared to fluorescent lamps, low-pressure rare gas discharge lamps basically have less temperature dependence and do not have problems such as deterioration of the fluorescent material, so they can always provide a stable amount of light. In addition, it is necessary to lower the discharge sustaining voltage and discharge starting voltage to obtain good overall efficiency, so it is a preheating type! It is necessary to have the poles (to overcome).

Of course, the amount of light required by an optical device differs depending on the equipment, but in general, fluorescent lamps for optical devices have the same tube diameter, such as 10W'j or 15W fluorescent lamps for general lighting. The lamp current is 0.7A to 1.2 people, which is a large current compared to 0.23A to 0.3 people for general lighting lamps, which requires a large amount of light. shall be. Furthermore, as optical devices become more sophisticated, the amount of light may be adjusted by dimming a fluorescent lamp instead of using mechanical parts such as slits. Taking these circumstances into consideration, the conditions required for a crystalline gas discharge lamp for optical equipment are that it requires a large amount of light compared to a neon sign, so the lamp current must be at least 0.2 A, and the IAA
There is a need for a lamp that does not reduce efficiency.

On the other hand, the luminous efficiency and light output of a neon gas discharge lamp are determined by the relationship among the filled gas pressure, tube diameter, and current.2 The inventors focused on the relationship between tube diameter and current, and as a result of various studies. It has been discovered that if the tube diameter is within a certain range, the efficiency is determined regardless of the current value, and a practical neon gas discharge lamp with no decrease in efficiency even at 9.1 A or more can be obtained.

The present invention will be explained in more detail with reference to Examples below.

Filament carp carrying a thermionic emissive material (3) Luminous poles sealed on both ends, outer diameter 14 to 26, length 43
Neon gas 0.1 torr ~ lOt in a 6-hole glass tube
I made a neon gas discharge lamp filled with orr. Lighting was carried out by using a choke coil as a ballast, preheating the electrodes with 3.6 AC, and applying an AC voltage between the electrodes. Prior to measurements, aging was performed with the aim of obtaining a completely stable lamp, but it was found that lamps with low sealing pressure had severe electrode damage, making it impossible to obtain a lamp with a long life. The inventors of the present invention determined that it would be impossible to obtain a practical lamp at a pressure of less than 1 torr even if improvements in the electrodes and changes in preheating current were taken into account, and decided to proceed with the study on a value of 1 torr or more. Incidentally, all lamps with 1 torr without dripping became defective within 100 hours.

Figures 1, 2, and 3 are graphs showing the relationship between current and luminous efficiency, and one curve A has a tube outer diameter of 26n.

Curve B is for 20 fins, and curve C is for 14 fins.

Figure 1 shows the case where the neon sealing pressure is 1 torr.

FIG. 2 shows the case of 5 torr, and FIG. 3 shows the case of 1 Qtorr.

(4) In either case, the larger the pipe diameter, the smaller the decrease in efficiency accompanying an increase in current. In other words, the larger the tube diameter, the less the tendency for the amount of light to saturate due to an increase in current.

FIG. 4 shows the relationship between the rate of decrease in efficiency and the tube outer diameter when the current is increased from 0.2 A to IA.

Curves a, b, and c each have a neon sealing pressure of 1 torr.
.

The cases of 5 torr and 10 torr are shown. Fourth
From the figure, it can be seen that if the outer diameter of the tube is 20 mm or more, a lamp with substantially constant efficiency with respect to current can be obtained.

The above data is based on commercial power supply, but 20
It was confirmed that almost the same results could be obtained with high frequency on the order of KHz or direct current lighting.

As explained above, this invention has a tube outer diameter of 20 fins or more,
By setting the sealed neon pressure to 1 torr or more,
This has the effect of providing a neon gas discharge lamp for optical devices that is highly efficient at 0.2 A or more.

[Brief explanation of drawings]

FIGS. 1, 2, and 3 show the relationship between current and luminous efficiency; FIG. 4 shows the relationship between the outer diameter of the RRZ tube and the rate of decrease in luminous efficiency. Agent Shin Kuzuno −! ! Figure 1 θ: 2 0.4 0.6 # 1
0 1.2 Den tA> 2nd figure 1(A) @3 figure o, 2o, 4ty, 6a, fjlθ 12e i
CΔ→4th F! llI tube outer diameter (mITI)

Claims (1)

[Claims] A rated rung current of 0.2 Å is made by enclosing neon of 1 torr or more and a preheated electrode in a glass tube with an outer diameter of 20 iI11 or more.
Neon gas discharge lamp for optical equipment.