JPS62163253A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To enhance the efficiency of light emission, by hermetically enclosing an excited light emission gas and a metal vapor having its ionization voltage near the optimal excitation voltage of the gas, to excite the atoms of the gas in a space between a cathode and an anode to emit light. CONSTITUTION:A cathode 3 and a reticulate anode 4 are disposed in a light- penetrated tube 1 so that the distance between the cathode and the anode is shorter than the mean free path of electrons. The inside surface of the tube 1 is coated with a fluorescent substance. An excited light emission gas of mercury or the like and a vapor of a metal such as cesium, which has its ionization voltage near the optimal excitation voltage of the gas, are hermetically enclosed in the tube 1. A fluorescent lamp is thus constituted. Ionization for generating a low-ionized plasma to neutralize space charge behind the anode 4 is caused by using an ionized gas other than the excited light emission gas. The voltage for the anode 4 is thus lowered to control the electrons to the optimal energy level to heighten the efficiency of light emission.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a so-called electron beam type firefly in which an anode and a cathode are provided in a tube filled with low-pressure gas [Background Art 1 As shown in FIG. An excited luminescent gas 2 such as mercury vapor is sealed inside the tube, and a cathode 3 heated by a filament and a mesh-like anode 4 are provided in the tube, and electrons are accelerated between the anode and cathode to create a space S behind the anode. A fluorescent lamp in which excited light is emitted by the collision of electrons with sulfur atoms and the emitted ultraviolet rays are converted into visible light by a fluorescent substance coated on the tube wall was developed in Japanese Patent Application Laid-Open No. 5.
It has been proposed in No. 7-130364, etc. In the figure, 5 is a filament heating power source, and 6 is an electron acceleration power source. According to this method, since the current-voltage characteristic is positive, current-limiting elements such as ballasts are not required, and there is a possibility that a lightweight and compact fluorescent lamp can be realized.

However, in the above-described conventional method, in order to triad the electrons by passing through the anode, the space charge formed by the electrons in the space behind the anode must be removed. Therefore, the mate has a relatively high voltage (
Approximately 10 cm) has been applied. Therefore, the electrons in the tube have the optimum energy (approximately 6 eV) to excite the mercury atoms and cause them to emit light.
), which reduced the luminous efficiency of the lamp.

[Object of the Invention] The present invention has been made in view of the above problems, and its purpose is to provide a fluorescent lamp with high luminous efficiency in the electron beam method that does not require a current limiting element as described above. is to provide.

[Disclosure of the Invention] Accordingly, the fluorescent lamp according to the present invention has a cathode and a mesh-like 7-meter spaced apart from each other by a distance shorter than the mean free path of electrons in a translucent tube filled with an excited luminescent gas. In a fluorescent lamp in which gas atoms are excited to emit light in the space behind the anode, a metal vapor having an ionization voltage near the optimum excitation voltage of the excited luminescent gas is sealed together with the excited luminescent gas. This method is characterized in that the roles of excited light emission and ionization are separated and assigned to two types of gas, respectively, so that excited light emission and ionization can be performed at optimal voltages.

[Embodiment 1] Fig. 1 shows an embodiment of the present invention, in which numeral 1 is a tube made of plastic whose inner surface is coated with fluorescent material, and inside tube 1 is a cathode 3 heated by a filament. is disposed, and a mesh-like electron-transmissive anode 4 is disposed at a distance m within the mean free path of electrons (for example, 1c111) from the cathode 3. The above configuration is the same as the conventional one, but in the present invention, as the sealed gas 2, a metal vapor having an ionization voltage near the optimum excitation voltage of the excited luminescent gas is sealed together with an excited luminescent gas such as mercury. The points are different.

Table 1 shows examples of filled gases, and as shown in the table, the optimum excitation voltage of mercury used as an excited luminescent gas
．． Cesium (ionization voltage: 3.89 V) or sodium (ionization voltage: 5.14 V), which have a slightly lower ionization voltage than 6.6, are preferable when focusing only on the ionization voltage.

However, when looking at the saturated vapor pressure, in the case of mercury and cesium, the ionizing gas is 1/100 of the excited luminescent gas.
However, in the case of mercury and sodium, the vapor pressure of sodium is very low, so it is necessary to raise the temperature inside the tube to increase the sodium vapor pressure. It is necessary to control the amount of mercury enclosed so that the vapor pressure (unsaturation) of mercury is optimal. Above, r:1. Therefore, it can be said that the combination of mercury and cesium is optimal for the fluorescent lamp of the present invention.

[Effects of the Invention] As described above, in the present invention, in order to prevent a rapid increase in electrons, provide positive voltage-current characteristics, and omit current-limiting elements such as ballasts, the anode cand opening is made by electronics. In a fluorescent lamp whose mean free path is shorter than the mean free path of the anode, the excitation of the gas atoms in the enclosed gas is emitted in the space behind the anode. The ionization effect for forming weakly ionized plasma is performed using an ionization gas different from the excitation emission gas, and the ionization voltage of the ionization gas is close to the optimum excitation voltage of the excitation emission gas. Since it is selected from a certain type of material, there is no need to electrify the gas for excitation and luminescence itself, and therefore the anode voltage can be lowered compared to the conventional example to control the electrons to the optimum energy level, thereby increasing the lamp energy. It has the advantage of increasing the luminous efficiency of.

[Brief explanation of drawings]

It is a keyaki-shaped diagram showing the pile 1Mg civil engineering climbing RJ1 labor naranbu Ichiusesai 11, where 1 is the tube body, 2 is the sealed gas, 3 is the cathode, 4 is the anode, 5 is the power source for filament, and 6 is for electron acceleration. It is a power source. Agent Patent Attorney Ishi 1) Chief 7 Figure 1 procedural amendment (voluntary) March 22, 1986

Claims (2)

[Claims] (1) A cathode and a mesh anode are placed in a transparent tube filled with an excited luminescent gas, separated by a distance shorter than the mean free path of electrons, and gas atoms are excited in the space behind the anode. What is claimed is: 1. A fluorescent lamp that emits light, the fluorescent lamp comprising a metal vapor having an ionization voltage near the optimal excitation voltage of the excited luminescent gas and sealed therein with the excited luminescent gas. (2) The fluorescent lamp according to claim 1, wherein mercury is used as the excited luminescent gas and cesium is used as the metal vapor.