RU2071619C1 - Method and discharge lamp for producing optical radiation - Google Patents

Abstract

FIELD: generation of optical radiation by electrical discharge in gas or in low-pressure lighting discharge lamps of various types. SUBSTANCE: method involves creation of gaseous discharge in inert gas atmosphere with radiating dope in bulb made of optically transparent material. Radiating dope is fullerene introduced at temperature of 300-800 C. Fullerene may be introduced in the form of fullerene-containing soot in concentration of at least 1.0 mass percent. It may be also introduced in the form of $$$. Discharge lamp implementing this method has bulb made of optically transparent material and filled with inert gas and radiating dope; used as the latter is fullerene in the amount of $$$ mcmol/cu.cm. Radiating dope may be introduced in bulb pip. EFFECT: facilitated procedure. 7 cl, 12 dwg

Description

 The invention relates to the electrical industry, and more specifically to methods for generating optical range radiation resulting from an electric discharge in a gas, as well as to low-pressure discharge lamps of various types: argon, xenon, krypton, sodium, mercury, mercury fluorescent and others.

 A known method of producing optical radiation, including the formation of a gas discharge in a mixture of sodium vapor at a pressure of 0.1-1.0 Pa with inert gases at a pressure of 100-1500 Pa in a cylinder of optically transparent material (see G. N. Rokhlin. Discharge sources Sveta. M. Energoatomizdat. 1991, p. 451-457).

 The known method for producing optical radiation is based on the resonance emission of sodium vapor (589.0 and 589.6 nm), i.e. almost monochromatic yellow light, which cannot be converted using phosphors, which makes the method unsuitable for general lighting. To implement the method requires the use of a chemically aggressive substance sodium.

 Known discharge lamp containing a cylinder made of patch glass, in which two electrodes are hermetically soldered. The balloon is filled with neon with the addition of 0.5-1.0% argon at a pressure of up to 600 Pa; sodium is also introduced into the balloon. The cylinder is equipped on the outside with small bulges for sodium condensation and mounted inside a vacuum external glass flask, the inner surface of which is covered with a thin film of indium oxide (see G.N. Rokhlin. Discharge light sources. M. Energoatomizdat. 1991, p. 451-457 )

 The known discharge lamp allows you to get only monochromatic yellow light, not amenable to conversion using phosphors, the lamp also contains a chemically aggressive substance sodium.

 A known method of producing optical radiation, including the creation in a container of optically transparent material of a gas discharge with a variable cross-section in length in an atmosphere of inert gas and mercury vapor. In this case, the magnitude of the current and pressure in the discharge volume is selected from the condition of ensuring periodic interruption of the discharge (see RF patent N 1814741 according to class N 01 J 61/72, publ. 07.05.93).

 The known method allows to generate radiation in the ultraviolet, visible and near infrared regions of the spectrum with high efficiency and high brightness. However, the use of mercury vapor in the known method makes it environmentally hazardous.

 Known mercury discharge lamp for lighting greenhouses, containing an optically transparent burner with hermetically sealed electrodes in it, filled with inert gas, mercury in the amount necessary to maintain the working pressure during the discharge, and emitting additives in the form of lithium, sodium and indium iodides taken in quantities wt. lithium iodide 8-18; sodium iodide 70-88; iodide indium 4-12 (see RF patent N 1816330 according to class N 01 J 61/18, publ. 05/15/93).

 The presence in the well-known lamp as a working substance of mercury is undesirable from the point of view of ensuring environmental safety in the production of lamps, during their operation and subsequent disposal.

 The closest set of essential features to the claimed method is a method for producing optical radiation, including the creation of a gas discharge from an optically transparent material in an inert gas atmosphere, mercury vapor and emitting additives in the form of metal halides at an inert gas pressure of 2660-39900 Pa (see USSR author's certificate N 1833927 according to class N 01 J 61/18, publ. 08/15/93).

 The known method, due to the introduction of emitting additives of various metals, allows you to create lamps with a high specific power, having the most diverse emission spectrum, with significantly higher efficiency compared to pure mercury lamps.

 The disadvantage of the prototype method is the need to use mercury, which is extremely undesirable from the point of view of ensuring environmental safety.

The closest set of essential features to the claimed discharge lamp for implementing the method is a discharge lamp containing a burner of an optically transparent material with hermetically sealed electrodes, filled with an inert gas, mercury and additives to provide the burner with halides of emitting metals, the additives used to provide the burner halides of silver, copper, zinc, while the components are taken in the following quantities, µmol / cm ³ :
Mercury 1.5-45.0
Additives for providing the burner with halides:
Silver 0.5-12.0
Copper 0.3-9.0
Zinc 0.2-8.0
and the inert gas pressure is 1.33-39.9 kPa (see RF patent N 2017263 according to class N 01 K 61/18, publ. 30.07.94).

 With all the advantages of the known discharge lamp prototype, it is environmentally unsafe due to the presence of mercury in its production, operation and subsequent disposal.

 The objective of the invention was to expand the arsenal of means for producing optical radiation by creating an environmentally friendly method for producing optical radiation and a discharge lamp for its implementation.

The problem is solved in that in the method for producing optical radiation, including the creation of a cylinder from an optically transparent material of a gas discharge in an atmosphere of inert gas with a radiating additive, fullerene is introduced as a radiating additive at a temperature of 300-800 ^o C. Fullerene can be introduced in the form fullerene-containing soot with a fullerene content of at least 1.0 weight. Fullerene can be introduced in the form of C ₆₀ .

The problem is also solved by the fact that in the discharge lamp for implementing the method of producing optical radiation, including a cylinder of optically transparent material, filled with an inert gas and a radiating additive, fullerene in the amount of 2.6 • 10 ^-9 6.9 • is introduced as a radiating additive 10 ^-3 μmol / cm ³ . Fullerene can be introduced in the form of fullerene-containing soot with a fullerene concentration of at least 1.0 weight.

Fullerene can be introduced in the form of C ₆₀ . Fullerene can be placed in the appendix of the aforementioned balloon.

The inventions are based on a phenomenon unexpectedly discovered by the authors of a qualitative change in the emission spectrum of a gas discharge in an inert gas when fullerene vapors are introduced into it. When fullerene, for example, C ₆₀ , is introduced at a vapor pressure above a certain limit (10 ^-7 Torr), the discharge radiation, which is determined in the absence of fullerene by the emission of inert gas atoms, passes into the emission of almost only fullerene molecules or complexes with its participation, lying in the near and far ultraviolet regions of the spectrum, as well as in the visible region. Ultraviolet radiation can be converted, if necessary, into the visible region of the spectrum using the corresponding phosphor deposited on the walls of the outer bulb surrounding the cylinder in which the gas discharge (the so-called burner) is carried out. The ultraviolet radiation detected by the authors can be associated not only with fullerene molecules, but also with complexes involving fullerene and fullerene ions, for example, C $\genfrac{}{}{0ex}{}{\text{+}}{\text{60}}$ . This radiation is not associated with inert gas atoms or with impurity atoms (hydrogen, oxygen, nitrogen, etc.), which may be present in the discharge if the discharge cylinder is not sufficiently degassed, since when the fullerene concentration decreases, the intensity of the emission lines in the ultraviolet region decreases, in particular, on the line at 308 nm, and at a concentration of less than 2.6 • 10 ^-9 μmol / cm ³ these lines practically disappear and the radiation again has a spectrum of inert gas atoms. An increase in fullerene concentration above 2.6 • 10 ^-9 μmol / cm ³ due to energy transfer leads to suppression of the emission of inert gas atoms and to an increase in the intensity of ultraviolet radiation on the 308 nm line. The concentration of fullerene in the discharge is determined by the temperature of the coldest section of the discharge cylinder. It was found that the temperature range in which fullerene determines the nature of the discharge radiation lies in the range from 300 ^o C to 800 ^o C. At temperatures below 300 ^o C, the fullerene concentration is less than 2.6 • 10 ^-9 μmol / cm ³ , line 308 nm disappears, and at temperatures above 800 ^o C (this temperature corresponds to a concentration of fullerene 6.9 • 10 ^-3 μmol / cm ³ ) the fullerene molecules begin to break down. Fullerene can be introduced in the form of fullerene-containing soot with a fullerene concentration of less than 1.0 weight. At a lower concentration of fullerene in soot, the ultraviolet radiation characteristic of fullerene disappears, the emission spectrum is determined by an inert gas. Fullerene can also be introduced in the form of C ₆₀ . Placing fullerene in the process of the balloon allows you to provide the necessary operating temperature of the fullerene.

The inventive method for producing optical radiation and a discharge lamp are illustrated by drawings, where: Fig. 1 shows the emission spectrum of a discharge electrode lamp filled with argon (at a pressure of 3024 Pa and a temperature of 230 ^o C) with the addition of fullerene C ₆₀ in the amount of 2.9 • 10 ^{- 11} μmol / cm ³ ; figure 2 shows the emission spectrum of a discharge electrode lamp filled with argon (at a pressure of 3024 Pa and a temperature of 600 ^o C) with the addition of fullerene C ₆₀ in the amount of 1.7 • 10 ^-4 μmol / cm ³ ; figure 3 shows the emission spectrum of a discharge electrodeless lamp filled with argon (at a pressure of 288 Pa and a temperature of 300 ^o C) with the addition of fullerene C ₆₀ in the amount of 2.6 • 10 ^-9 μmol / cm ³ ; figure 4 shows the emission spectrum of a discharge electrodeless lamp filled with argon (at a pressure of 288 Pa and a temperature of 800 ^o With the addition of fullerene C ₆₀ in an amount of 6.9 • 10 ^-3 μmol / cm ³ ; figure 5 shows the emission spectrum of a discharge electrodeless a lamp filled with helium (at a pressure of 576 Pa and a temperature of 200 ^o C) with the addition of fullerene C ₆₀ in an amount of 2.8 • 10 ^-12 μmol / cm ³ ; Fig. 6 shows the emission spectrum of a discharge electrodeless lamp filled with helium (at a pressure 576 Pa and a temperature of 400 ^o C with the addition of the fullerene C ₆₀ in an amount of 2,6 • 10 ^-7 mol / cm ³ to f D.7 shows the emission spectrum of an electrodeless discharge lamp filled with neon (at a pressure of 288 Pa and a temperature of 200 ^o C) with the addition of the fullerene C ₆₀ in an amount of 2,8 • 10 ^-12 mol / cm ^3; Figure 8 shows the emission spectrum of the discharge an electrodeless lamp filled with neon (at a pressure of 288 Pa and a temperature of 350 ^o C with the addition of C ₆₀ fullerene in an amount of 2.6 • 10 ^-8 ; Fig. 9 is a radiation spectrum of a discharge electrodeless lamp filled with argon (at a pressure of 288 Pa and temperature 300 ^o C) with the addition of fullerene-containing soot with a concentration of fullerene C ₆₀ 1 weight. (2.6 • 10 ^-9 μmol / cm ³ ); figure 10 shows in section a discharge lamp (for ultraviolet radiation); figure 11 in the context of a discharge lamp with a phosphor; 12 is a sectional view of a discharge lamp in an electrodeless embodiment.

 In Fig.1-9, the abscissa axis shows the radiation wavelengths λ in nm, and the ordinate axis shows the radiation intensity in relative units (the scale is the same for pairs of figures: for Fig.1 and Fig.2, for Fig.3 and Fig.4 , for FIG. 5 and FIG. 6, for FIG. 7 and FIG. 8).

 The discharge lamp includes a sealed cylinder 1 (burner) made of optically transparent material, such as quartz, ceramic or uvolev glass. In the variant with the phosphor layer (Fig. 11), the sealed balloon 1 is placed in an external flask 2 evacuated to reduce heat transfer, on the inner surface of which a layer of phosphor 3 is applied to convert the spectrum of the generated radiation from the ultraviolet region to visible. The pressurized cylinder 1 is filled with an inert gas (for example, argon, xenon, krypton, or mixtures thereof). The cylinder 1 can be equipped with working electrodes 4 and 5 (for example, tungsten), and in the electrodeless version of the discharge lamp (Fig. 12), such electrodes are absent and a high-frequency circuit 6 connected to a high-frequency generator (not shown) is used to excite the discharge. Fullerene or fullerene-containing soot 7 is placed in the cold parts of the cylinder 1, for example, behind the electrodes 4, 5 in the processes 8 of the cylinder 1.

Using a discharge lamp of the inventive method is as follows. The electrodes 4, 5 (in the electrodeless version of the lamp on circuit 6) are supplied with the voltage necessary to ignite the discharge in the cylinder 1. An electric discharge occurs between the electrodes 4, 5, and the bulb 1 is heated. The temperature of the cold sections of the bulb 1 is selected by the discharge current. where fullerene is located, in the range of 300 800 ^o C. Vapors of fullerene 7 in an amount lying respectively in the range from 2.6 • 10 ^-9 μmol / cm ³ to 6.9 • 10 ^-3 μmol / cm ³ enter the electric discharge zone , as a result, optical radiation is generated in the ultraviolet and visible areas. If it is necessary to obtain optical radiation of a different spectral composition, a layer of the corresponding phosphor 3 is applied to the inner surface of the flask 2, which converts ultraviolet radiation from the balloon 1 into the visible region of the spectrum.

Example 1. A discharge lamp was made in the form of a quartz cylindrical cylinder with a diameter of 20 mm, into the ends of which two tungsten electrodes were soldered. A process was made in the middle of the balloon into which C ₆₀ fullerene was placed. The cylinder was connected to a vacuum system. Tungsten spirals were wound on the balloon and on the appendage, which made it possible to heat the discharge lamp, varying both the temperature of the cylinder walls and the process temperature from room temperature to 800 ^° C independently of each other. The temperature was measured using thermocouples placed on the wall of the balloon and on the surface of the process with fullerene. The cylinder using a vacuum system was previously degassed, and then was filled with argon to a pressure of 3024 PA. The process temperature was set equal to 230 ^o C. Since the process temperature was set below the cylinder wall temperature, the vapor pressure of the fullerene in the discharge was determined by the process temperature and was 10 ^-9 Torr, which corresponded to the amount of fullern 2.9 • 10 ^-11 μmol / cm ³ . A constant voltage of 600 V was applied to the electrodes, sufficient for breakdown of the interelectrode gap, after which the voltage decreased to 300 V. The radiation emitted by the axial region of the discharge was focused on the entrance slit of the spectral device, the output of which was connected through a photoelectronic multiplier and amplifier to a recording device that allowed record the emission spectrum of the discharge in the wavelength region of 200-800 nm. The emission spectrum recorded by the device is shown in FIG. It is a radiation of argon atoms that fills a lamp bulb. Then, the optical radiation of the discharge lamp was recorded at a temperature of fullerene vapor of 600 ^o C (which corresponded to 1.7 • 10 ^-4 μmol / cm ^3. The emission spectrum is presented in figure 2. There was a "suppression" of the argon lines, and new lines appeared in the near and far ultraviolet regions of the spectrum, as well as an increase in the intensity of the continuous spectrum.

Example 2. An electrodeless discharge lamp was made from a quartz cylinder with a diameter of 10 mm, which was connected to a vacuum system. A high-frequency circuit was wound on a part of the surface of the balloon, the middle part of the balloon was reduced by a process in which C ₆₀ fullerene was placed. Tungsten spirals for heating were wound on the walls of the balloon and on the process, which made it possible to vary both the temperature of the walls of the balloon and the temperature of the process in the range from room temperature to 800 ^° C independently of each other. The discharge lamp was previously degassed using a vacuum system, and then it was filled with argon to a pressure of 288 Pa. The discharge in the lamp was ignited using a high-frequency electromagnetic field with a frequency of 100 MHz. The temperature measurement and registration of the emission spectrum were carried out as in Example 1. The emission spectra were recorded at a fullerene vapor temperature of 300 ^° C (see Fig. 3) and 800 ^° C (Fig. 4). From a comparison of these spectra with the emission spectrum of argon (Fig. 11), the appearance of intense radiation in the far and near ultraviolet regions in the temperature range of fullerene vapor 300 800 ^o C. is clearly visible.

Example 3. An electrodeless discharge lamp made as in example 2 was filled with helium to a pressure of 576 Pa. The emission spectra of the discharge lamp were recorded at a temperature of fullerene vapor of 200 ^o C (Fig.5) and 400 ^o C (Fig.6). At a temperature of 200 ^° C, the emission spectrum was radiation from helium atoms, and at 400 ^° C, radiation was detected in the near and far ultraviolet regions due to the presence of fullerene.

Example 4. An electrodeless lamp made as in example 2 was filled with neon at a pressure of 288 Pa. Radiation spectra were recorded at a vapor temperature of fullerene of 200 ^o C (Fig.7) and 350 ^o C (Fig.8). At 200 ^o С the emission spectrum corresponded to the neon emission spectrum, at 350 ^o С the neon lines became less intense and radiation appeared in the near and far ultraviolet regions due to the presence of fullerene.

Example 5. An electrodeless lamp was made as in example 2, but instead of fullerene, fullerene-containing soot was placed in the process at a concentration of fullerene of 1 weight. and the cylinder was filled with argon to a pressure of 288 Pa. The radiation spectrum was taken at a temperature of 300 ^o C (Fig.9). When comparing it with the spectrum of argon (Fig. 1), the appearance of radiation in the near and far ultraviolet regions was detected due to the presence of fullerene vapors.

Claims (7)

1. A method of producing optical radiation, including the creation of a gas discharge in an inert gas atmosphere with a radiating additive in a cylinder of optically transparent material, characterized in that fullerene is introduced as a radiating additive at 300 800 ^o C.  2. The method according to claim 1, characterized in that fullerene is introduced in the form of fullerene-containing carbon black with a concentration of fullerene of not less than 1.0 wt. 3. The method according to claim 1, characterized in that the fullerene C _{6 0} is introduced. 4. A discharge lamp for receiving optical radiation, including a cylinder of optically transparent material, filled with an inert gas and a radiating additive, characterized in that fullerene in the amount of 2.6 • 10 ^{- 9} 6.9 • 10 ^{- 3} μmol is introduced as a radiating additive / cm ³ .  5. The lamp according to claim 4, characterized in that fullerene in the form of fullerene-containing soot with a fullerene concentration of at least 1.0 wt. 6. The lamp according to claim 4, characterized in that fullerene C _{6 0 is} introduced as a radiating additive.  7. The lamp according to claim 4 or 5 and 6, characterized in that the radiating additive is placed in the process of the said balloon.

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