JPS5853152A - High voltage alkali metal lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to high pressure sodium lamps, and more particularly to high pressure sodium lamps with improved efficiency.

Sodium vapor lamps are high intensity discharge light sources in which all of the light output is generated within an arc discharge tube.

Light output results from the passage of electrical current through an ionizing gaseous medium contained within the inner arc tube and maintained at a relatively high temperature. This temperature is generally about 1.4000 and about 1,
500°K. Because of this high temperature, these lamps are generally surrounded by an outer light-transparent jacket that acts as an insulating and protective barrier. Generally 1. The area between the pressurized arc tube and the outer jacket is mostly vacuum or contains an inert gas such as argon. An arc discharge containing ionizing sodium is maintained within the arc tube. Arc tubes are generally cylindrical structures with electrodes at both ends. High pressure sodium lamps are particularly desirable because of their high energy efficiency.

In these cases, the color of the spectrum of the lamp does not matter;
Moreover, it is particularly useful for industrial and outdoor applications where a high level of light output is desired.

An important consideration in the design of high-pressure sodium lamps is ``wall loading''. Wall loading is a lamp parameter measured in power per unit area (e.g., watts per square centimeter). The outlet supplied to the lamp is divided by the area of the inner wall of the arc tube.It is an important parameter because it has a significant influence on the temperature of the arc tube wall. , is evidenced by the fact that it is the arc tube wall temperature that has an important influence on the overall lamp efficiency as measured in lumens per watt.Therefore, a predetermined optimal arc tube wall temperature It is highly desirable to be able to design a high pressure sodium lamp that can maintain

In other lamps, including some of the brightest lamps, infrared reflective coatings reflect infrared light back into the lamp filament to maintain elevated temperatures without providing additional electrical energy. Used to reflect radiation? 1 will be given. While these coatings reflect infrared radiation, they nevertheless transmit visible light. An important disadvantage of luminous lamps of this configuration is the severe requirement to concentrate the reflected infrared radiation in the narrow volume occupied by the lamp filament.

In areas not related to luminous lamps, J.F. Weymouth and E.F. Weiner pointed out that important improvements in the efficiency of high-pressure sodium lamps were achieved using large diameter arc tubes. ing. (“Analysis of Factors Affecting the Efficiency of High-Pressure Sodium Lamps” Contributor; JF Weymouth and EF Winner-1IE8 Journal, Vol. 10, m4, p. 237 (19
81). For example, current conventional high pressure sodium lamp arc tubes generally have internal diameters of about 5 m to 7 m. If the temperature of the arc tube wall is maintained in the desired range between about 1,400° and about 1,500°, an inner diameter of about 10s+a+ to about 18′ will increase sodium lamp efficiency. be able to. This is difficult to do because an increased internal diameter of the arc tube naturally brings up the fact that the area of the internal wall of the arc tube is also increased - proportionally to its increased internal diameter. . This increase in arc tube wall area means a reduced wall load. Weymouth and Wiener proposed to solve this problem by using arc tubes made of materials such as Ittria, which have an even lower emissivity than the common polycrystalline alumina arc tubes, especially in the infrared spectral region. has been raised. .

However, ittria is expensive and therefore it is not economical to use it as a material for arc tubes.

U.S. Pat. No. 3,662,203 issued May 9, 1972 to Tarr et al. discloses a high pressure sodium lamp. Kuhl et al. suggest that it is desirable to meter the outer jacket close to the arc tube so that infrared radiation from the outer jacket is re-radiated to impinge on the arc tube to maintain storage temperatures. . Naturally, due to the high temperature (500° C.) the outer jacket must be made of expensive quartz glass. Further, the Tarr et al. patent teaches that it is desirable to use arc tubes having an inner diameter of up to 25 mm.

This is too high a pressure to produce efficient light in an IJ lamp. Moreover, the distance between the arc tube and the outer jacket is close enough to overheat an infrared reflective coating applied to the outer jacket.

United States Patent Nh 3,400,288 issued September 3, 1968 to R. Gross discloses a sodium vapor lamp with an infrared reflective coating.

However, this patent relates only to low pressure sodium lamps, for which changes in arc tube diameter do not result in a comparable change in efficiency compared to high pressure sodium lamps. In short, the mechanisms that produce light are different. Furthermore, Gross nowhere points out the evaluation of changing the diameter of the arc tube to "optimize" the diameter of the arc tube.

Fall et al. US Pat. 1 shows a high-pressure I-IJ lamp with a dichroic reflector located therein. However, there is no evaluation of the use of such coatings in lamps with large diameter arc tubes.

Also, there is no teaching in the Fall et al. patent regarding a desired range of arc tube inner diameters. Other U.S. patents of general importance in related lamp technology include Nn 3,221.19 s: 3,374
,377: 3,325,662: 3,963,9
s 1 and 4,071,798. Several of these patents describe reflective coatings used in discharge lamps. However, these coating materials do not reflect infrared rays or transmit visible rays. Additionally, U.S. Patent Application No. 8, filed in August 1981 and assigned to the same assignee for the present invention. N (R
D-13,072), Silverstein demonstrated optimal films and film thicknesses for the reflective coatings of the present invention. Furthermore, the aforementioned patent applications are used in the text for reference. In particular, 150
Films with a thickness of ±30 nm are mentioned as preferred. A filter that transmits light rays and reflects heat rays is disclosed in the American patent m3,9 by Costeilan et al.
49. It is based on indium oxide coated with tin and supported on a transparent substrate according to Z59. J.G.
My IE8 journal published in July 1979 (
The paper "Thermal Storage System for Arc Lamps" written by c,s@Liu in page 220) concludes that more effective HID lamps cannot use infrared reflective layers.

In the same paper, E. F. Weiner also discusses reasons for not using smaller volume arc tubes.

In short, it is viewed as desirable to increase the efficiency of high pressure sodium arc discharge lamps by increasing the arc tube inner diameter. However, it has been concomitantly observed that if no means are found to compensate for the falling arc tube wall temperature, this will result in reduced wall loads and an actual reduction in efficiency.

According to a preferred embodiment of the invention, the high pressure IJ discharge lamp is coated with an infrared reflective material.

This reflective material is In2O3: Sn or 8n02:
F or other suitable reflective material, which is a material that reflects infrared light and transmits visible light. In this example, the arc tube inner diameter is about 10-18 m. A preferred range for arc tube inner diameter is approximately 12 to 14-j-+shift
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- The ath-ray reflective coating is substantially transparent to wavelengths less than about 1 micron. In yet another preferred embodiment, the outer jacket is generally cylindrical in shape to match the shape of the arc tube itself.

It is therefore an object of the invention to increase the efficiency of high pressure sodium lamps. Yet another object of the present invention is to maintain the arc tube wall temperature in a high pressure sodium lamp at or near the optimum temperature. A further object of the invention is to provide a high pressure sodium lamp with a reduced wall load. It is a further object of the present invention to provide a lamp having an infrared reflective coating on the inside of the outer jacket to facilitate the use of conventional polycrystalline alumina as the arc tube material.

The subject matter of the invention is particularly pointed out and distinctly claimed hereinafter.

A further understanding, however, of the invention, as well as its objects and advantages, as well as its construction and carrying out, may be understood by reference to the following description of the accompanying drawings, in which: FIG.

That is, the present invention was proposed in view of the above-mentioned drawbacks, and has a large diameter arc tube with an infrared reflective film formed inside the jacket, making it possible to maintain the wall of the arc tube at a predetermined high temperature. The purpose of this invention is to provide a high-efficiency high-pressure sodium lamp.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a lamp 10 according to an embodiment.

Reference numeral 20 denotes a cylindrical arc discharge tube, which contains an ionized discharge substance such as sodium or other alkali metals. Both ends of the arc tube 20 are covered with conductive lids 2.
Approximately 12 to 14M is preferable depending on 2.24, but approximately 10 to 1
It may be 8m. This inner diameter greatly influences the effectiveness of the invention.

Arc tube 20 is located within jacket 11 and is also mechanically supported by electrode 16 and electrode 18 which supplies current into arc tube 20 through lid 22 . A portion of the electrode 18 is also wrapped around the recess 17 of the jacket 11, thereby mechanically supporting the electrode 18.

Also, in order to prevent adverse effects due to thermal expansion, a flexible strip 19 is provided between the electrode 18 and the lid 22, thereby providing an effective mechanical and electrical connection. The stem of lamp 10 is of a conventional screw type. Also, the space 15 between the optically transparent jacket 11 and the arc tube 20
is a vacuum. However, an inert gas such as argon may also be included. The feature is that an infrared reflective film 30 is formed on the inner wall of the cylindrical jacket 11. This film, which is created by one or more materials, essentially allows visible light to pass through as described above, but reflects infrared light and prevents it from entering the arc tube 20.
It bounces back towards.

Heretofore, it has been thought that the use of such infrared reflective coatings to improve high pressure I-IJ vapor lamps is not beneficial. However, the effect is significant under conditions where the inner diameter of the arc tube 20 is large. By the way, it is certainly possible to increase lamp efficiency by increasing the diameter of the arc tube. However, as the diameter of the arc tube increases, the area of the tube wall also increases, which reduces the "wall load." Unless this reduction in wall load is compensated for in some way, the overall efficiency of the lamp cannot be increased. According to the present invention, an infrared reflective coating reflects and focuses infrared radiation onto the arc tube wall, thereby maintaining the arc tube wall at a temperature of about 1,400° to 1,500°. . According to the invention, this is possible without using expensive Ittoria arc tubes. Furthermore, the arc tube 20 can be made of ordinary alumina tube wall. As shown in the figure, the jacket 11 usually has a cylindrical shape because the arc tube 20 has a cylindrical shape. This is in contrast to the egg-shaped jackets commonly used. Egg-shaped ones are often used, but they are not very effective. An infrared reflective coating is formed over almost the entire area of the jacket wall that is coaxial with the arc tube. This maximizes the amount of reflected infrared rays that reach the arc tube wall, making it possible to maintain the temperature of the arc tube wall.

This infrared reflecting film reflects almost all electromagnetic waves with wavelengths of 3 microns or more toward the arc tube 20.

This allows for the desired visible light produced by the lamp to be radiated out and for the use of infrared radiation to maintain a predetermined arc tube wall temperature. This is possible even if the inner diameter of the arc tube is large. Since the infrared reflective film is damaged by overheating, the jacket 11 is attached to the arc tube 20.
It is desirable to keep it away from the This distance must be at least 10 m.

Figure 2 shows the lamp efficiency (
Indicates the approximate change in lumens/watt).

However, the curve in the figure does not take into account the reflective film. However, according to the present invention, the size of this inner diameter is 10 to 10.
The length is preferably 18 meters, preferably 12 to 14 meters.

The high pressure sodium lamp of the present invention is operated at a sodium vapor pressure of about 10 to 100 atmospheres. The lamp also has xenon as starting gas at about 10 to 200 atmospheres under room temperature conditions. Also included is mercury at a vapor pressure of about 500 to 1500 atmospheres in operating conditions. From the foregoing it can be seen that the present invention provides a lamp having a highly efficient light source. It will also be appreciated that the reduction in wall load due to the increase in the internal diameter of the arc tube is compensated for by the infrared reflective coating, and furthermore, the infrared radiation, which is an important part of the energy radiated by high-efficiency discharge lamps, is effectively utilized and the arc tube It will also be understood that the temperature is maintained at the required temperature.

Although the invention has been described in detail according to the embodiments, many modifications will be possible to those skilled in the art. Accordingly, modifications that are within the spirit of the invention are considered to be within the scope of the following claims.

[Brief explanation of the drawing]

FIG. 1 is a front view including a partial sectional view of a lamp according to a preferred embodiment of the present invention, and FIG. 2 is an explanatory diagram of the relationship between arc tube diameter and efficiency. 10: Lamp 11: Jacket 16.18: Electrode 20: Arc tube 30: Infrared reflective film 71,2 tons 10 1/30 ・j4 1/6 -/4 Procedural amendment (Platinum 1. Incident) Display Showa #; 7th year 'ni'fs 1st
E 29 (? No. 2, Name of the invention ``High-pressure alkali metal lamp 3, Relationship with the case of the person making the amendment: Applicant Yague 1υ]: Rek #-q, Rek Compony 4,
Agent Ml-1 Mutsuto, $=-511 Ki Ai Hiyo゛Sooke'Lzu1゜e@）tai'tE苧1F, Yujit-IN Riichi, tI4M Dai゛ Ah, th-71 letter I protection*, wow. Procedures Written amendment (voluntary) 1. Indication of the case Patent Application No. 152868 of 1982 2. Name of the invention High-pressure alkali metal lamp 3. Person making the amendment Relationship to the case Applicant General Electric Company 4, Agent Contents of amendment in Column 6 of "Detailed explanation" (11 The scope of claims in the specification is amended as shown in the attached sheet. (2) "This film" on page 12, line 9 of the specification drawing is amended to "this film 30" (3) The “infrared reflective film” on page 12, line 13 of the specification drawing [
Correct with infrared reflective film 30J. (4) "Infrared reflective film" on the second line of page 13 of the specification cylinder is corrected to "infrared reflective film 30." (5) Specification tube 1
"Infrared reflective film" on page 3, line 13 is changed to "Infrared reflective film 30".
” he corrected. (6) "Arc tube" on page 13, line 14 of the specification is replaced with "
arc tube 20”. (7) "Infrared reflective film" from line 17 to line 18 on page 13 of the specification cylinder is corrected to "infrared reflective film 30." (8) "Arc tube" on page 14, line 3 of the specification is corrected to "arc tube 20J." (9) "Infrared reflective film" on page 14, line 4 of the specification is corrected as [infrared reflective film 30J. do. a. On page 15, line 1 of the specification, "arc tube" is corrected to "arc tube 20." αυ "Infrared reflective film" on page 15, line 2 of the specification is corrected to "infrared reflective film 30." 02 "Arc tube" on page 15, line 5 of the specification is corrected to "arc tube 20." Claims il+ has electrodes (16, 18) at both ends, and about 1
an elongated visible light transparent pressurizable arc tube (20) having an inner diameter of 0 to 18 m; an ionizable alkali metal substance contained in the arc tube; A high-pressure alkali metal lamp characterized in that it has a jacket (11) that is transparent to visible light and has a visible light-transmissive jacket (11) formed with a single infrared reflective film (30) capable of reflecting infrared light. (2) The high-pressure alkali metal rung according to claim 1, wherein the alkali metal substance is sodium. (3) The inner diameter of the arc tube (20) is approximately 12 to 14
A high-pressure alkali metal lamp according to claim 1. (4) The high-pressure alkali metal lamp according to claim 1, wherein the infrared reflective film (30) reflects electromagnetic waves having a wavelength of about 3 microns or more. (5) The arc tube (
20. A high-pressure alkali metal lamp according to claim 1, further comprising means for mechanically supporting the arc tube (20) and compensating for thermal expansion of the arc tube. (6) The arc tube (20) and the jacket (1)
The high-pressure alkali metal lamp according to claim 1, wherein σ has a cylindrical shape.

Claims (1)

[Scope of Claims] (11) An elongated, visible light-transparent, pressurizable arc tube having electrodes at both ends and having an inner diameter of about 10 to 18 m, and an ionizable arc tube disposed within the arc tube. A high-pressure alkaline, metal lamp comprising: a metal material; and a jacket that surrounds the arc tube and is transparent to visible light and has an infrared reflective coating formed on the arc tube to reflect infrared rays. (2) The high-pressure alkali metal lamp according to claim 1, wherein the alkali metal is sodium. (3) The high-pressure alkali metal lamp according to claim 1, wherein the arc tube has an inner diameter of 12 to 14 m. Metal lamp 0 (4) The high-pressure alkali metal lamp according to claim 1, wherein the infrared reflective film reflects electromagnetic waves with a wavelength of about 3 μ or more. (5) The arc tube in the jacket is mechanically removed. A high-pressure alkali metal lamp according to claim 1, further comprising means for supporting the arc tube and compensating for thermal expansion of the arc tube. (6) The arc tube and the jacket are cylindrical in shape. The high-pressure alkali metal lamp according to item 1.