CN100351194C - Long life halogen cycle incandescent lamp and glass envelope composition - Google Patents

Abstract

A long life, halogen cycle incandescent lamp (30) operable above 85 volts. The lamp comprises a transparent glass envelope (34) enclosing a tungsten filament (45); a pair of curved electrical leads (42.44) connected to the filament and extending out of the envelope to a voltage source greater than 100 volts; and A halogen-containing filling gas filled in the capsule at 1 atm. The capsule is made of _a five-component alkaline earth aluminosilicate glass whose main components include greater than 58 wt% to 64 wt% _SiO2 , 14 to 17 wt% _Al2O3 , 0 to 1 wt% _B2 O ₃ , 1 to 6 wt % MgO, 6 to 12 wt % CaO, 7 to 17 wt % BaO, and 0 to 1.5 wt % ZrO ₂ .

Description

Long-life halogen cycle incandescent lamp and glass envelope composition

This application is a divisional application of the invention patent application with the application number 98808908.4 (PCT/US98/18745) and the application date on September 10, 1998.

This application claims U.S. patent application filed September 12, 1997, provisional application number 60/058,712; U.S. patent application, October 10, 1997, provisional application number 08/948565, and filing date 1997 Interest in German patent application with application number 19747355.5 dated October 27, 2009.

technical field

The present invention relates to lamps, in particular to incandescent halogen lamps, and more particularly to glass for halogen lamp envelopes.

Background technique

Lamps operated by a tungsten-halogen cycle are known. The lamp operates by containing an inert fill gas, such as neon, nitrogen, argon, krypton, or xenon, or mixtures thereof, together with a halogen, usually bromine, in combination with volatile tungsten escaping from the hot filament. In a lamp, a gaseous substance reaches concentration equilibrium between the temperature limit defined by the incandescent filament and the coldest point in the lamp envelope. The cold spot temperature should be high enough to prevent condensation of any tungsten halides, and as long as this condition is met, the continuous delivery cycle operation can keep the tungsten from volatilizing onto the lamp envelope.

Many hard glasses, such as aluminosilicates, have been used with varying success in tungsten-halogen lamps. These glasses include glass numbers 1720, 1724, and 1725 from Corning Incorporated; glass numbers 8252 and 8253 from Schott; and glass number 180 from General Electric.

Glasses 1720, 1724 and 8252 have been successfully used in low voltage (i.e. 12V) applications, such as automotive headlights with a working wall temperature below 500°C; application, since the wall temperature is much higher than 500°C, these glasses are not suitable because it cannot maintain a good seal. This condition is due to contraction of the glass structure in operation. The stresses caused by the shrinking glass can exceed the breaking strength of the glass and eventually cause the lamp seal to fail.

Other glasses, such as No. 1725, No. 180 and No. 8253 glasses have substantially higher glass deformation points, and are suitable for higher wall temperatures due to reduced glass bulb size and higher voltage, that is, when the voltage exceeds 85 volts. At this time, the glass It will not be destroyed by shrinkage, but eventually there will be blackening due to tungsten deposition on the inner wall of the bulb, so there will be non-passive lamp damage, that is, the lamp envelope will explode. Ideally, lamp damage should be passive damage, that is, damage caused by filament breakage. Commonly used halogen gases are HBr or _CH3Br . As mentioned above, the concentration of bromine (or other halogens) is the key to controlling the cycle of halogens with tungsten filaments. The above glass works well initially, and after a while the alkaline earth cations react with the bulb walls, consuming bromine from the halogen cycle. The reaction products are usually BaBr ₂ and CaBr ₂ , and white smoke appears on the inner surface of the lamp envelope. The performance of such conventionally designed halogen lamps is limited by this reaction.

It has been proposed to coat the inner surface of the lamp envelope with a silica barrier layer to reduce the reaction of alkaline earth cations with bromine (see U.S. Patent 5,473,226 assigned to the assignee of the present invention), but this solution increases the cost and does not Not entirely effective.

If a glass can be developed that can eliminate or substantially reduce the chemical reaction between the halogen gas in the lamp and the glass material when a voltage above 85 volts is applied, thereby improving the performance of the lamp (capable of maintaining increased brightness) and life, it is A major advance in this field of technology. That is, the goal of exceeding 2,500 hours can be achieved without substantially reducing the brightness of the lamp.

Introduction of the invention

Accordingly, the object of the present invention is to overcome the disadvantages of the prior art.

Another object of the invention is to improve the performance of halogen cycle lamps.

Still another object of the present invention is to provide glass for tungsten-halogen lamps which can achieve the above effects while keeping the cost low.

According to one aspect of the present invention, to achieve these objects, there is provided a long-life halogen cycle incandescent lamp capable of operating at a voltage above 85 volts, comprising: a transparent glass envelope enclosing a tungsten filament; connecting the filament, and A pair of lead wires protruding from the enclosure to connect to a power source with a voltage above 85 volts; a halogen-containing filling gas filled into the enclosure at a pressure of at least three atmospheres. The capsule is composed of an alkaline earth aluminosilicate glass consisting essentially of greater than 58 to about 64 wt% _SiO2 , about 14 to about 17.5 wt% _Al2O3 , 0 _to about 1 wt% _B2 O ₃ , 1 to about 7 wt % MgO, about 5.5 to about 14 wt % CaO, about 6 to about 17 wt % BaO, 0 to about 8 wt % SrO, and 0 to about 1.5 wt % ZrO ₂ . Other trace compounds such as _CeO2 or _TiO2 may be present in amounts below 1 wt%. In a preferred embodiment of the invention, the capsule is constructed of an aluminosilicate glass with reduced affinity for halogens comprising: 59 to about 61 wt% _SiO2 , about 15.3 to about 17.2 wt% _{Al2O 3} , about 0.3 to about 0.5 wt% _B2O3 , 1 to about 6.5 wt% _MgO , about 5.9 to about 13.5 wt% CaO, about 6.5 wt% to about 9.5 wt% BaO, 0 to about 8 wt% SrO , about 0.05 to about 1 wt % ZrO ₂ , about 0 to about 0.3 wt % CeO ₂ and about 0 to about 0.5 wt % TiO ₂ .

Brief description of the drawings

There is only one drawing, which is a cross-sectional view of a tungsten-halogen lamp used in the present invention.

Best Mode for Carrying Out the Invention

With reference to the following description and appended claims in conjunction with the above-mentioned drawings, the present invention and other further objects, advantages and capabilities of the invention can be better understood.

Referring now more specifically to the drawings, a lamp 30 is shown having a longitudinal axis L and comprising an outer shell 32 and an inner shell 34, a frame assembly 36 and a base 38, the outer shell 32 having a glass neck portion 40. The inner housing 34 is a tungsten-halogen incandescent envelope with a filament 45 in which are bent electrical leads 42 and 44 which are connected to a power source outside the housing 34 at a voltage above 85 volts. Enclosure 34 is mounted on frame assembly 36 in this example.

The capsule 34 is constructed of the glass of the present invention and contains a fill gas consisting of an inert gas and a halogen. In a preferred embodiment of the present invention, the filling gas includes 95% Kr, about 5% _N2 , and 0.10% HBr, and the gas is at 3 to 8 atmospheres.

The main components of the aluminosilicate glass used to form the capsule 34 include: >58 wt% to about 64 wt% SiO ₂ , about 14 to about 17.5 wt% Al ₂ O ₃ , 0 to about 1 wt% B ₂ O ₃ , about 1 to about About 7 wt% MgO, about 5.5 to about 14 wt% CaO, about 6 to about 17 wt% BaO, 0 to about 8 wt% SrO, 0 to about 1.5 wt% _ZrO2 . In preferred embodiments of the present invention, boria and zirconia can be omitted without affecting lamp operation; however, a small amount of boria and zirconia must be added to facilitate the melting process. In order to control the liquid state, a small amount of zinc oxide can be added, and a small amount of CeO ₂ and/or TiO ₂ can be added to control the UV absorption limit. Suitable for use in tea light glass. Up to 2 wt% Br can be added. This corresponds to a maximum of about 0.6 wt% Br in the resulting glass. Because the compounds used, such as _BaBr2 are volatile.

The bromine consumption of some glasses of the present invention was tested in the following manner compared to prior art glasses. Fused quartz reaction vessels about 5 inches in length and about 5 inches in diameter were filled with enveloped glass tubes made of No. 8253, 180, 1725, 1724, 1720 glass compositions and glass of the present invention. The compositions of these glasses are listed in Table I.

Table I 1720 1724 8252 1725 180 8253 Oxide Corning Corning Schott Corning GE Schott SiO ₂ 60.63 57.2 60 63.4 62.1 61.9 Al ₂ O ₃ 16.22 16.3 14.5 14.5 14.3 16.2 B ₂ O ₃ 5.02 4.35 4.5 0.05 0 0.34 MgO 8.17 5.79 2.0 0.2 0 0.05 CaO 9.45 8.03 10.0 11.2 6.5 12.5 BaO 8.07 9.0 10.4 16.8 7.7 SrO 0 0.2 0.2 0.1 Na ₂ O 0.51 0.038 0.03 0.02 0.08 K ₂ O 0.024 0.02 0.01 0.01 _ZrO2 0.16 0 0 1.1 _{Fe2O3 _} 0.048 0.041 0.033 0.031 TiO ₂ 0.21 BaO/CaO[moles] 0.37 0.33 0.34 0.95 0.22 MgO/CaO[moles] 1.20 1.00 0.28 Molar%RO 23.0 22.4 19.2 18.3 16.1 18.5 physical properties Softening point[℃] 915 926 940 993 1020 1000 Annealing point[℃] 712 726 725 778 786 783 Deformation point [°C] 668 674 716 733 733 Thermal expansion 23-300C[x10-7/C] 42 44 46 45 43 45 Density [g/cc] 2.52 2.56 2.63 2.72 2.68 2.62

The quartz reaction vessel was evacuated, backfilled with a gas consisting of 80% Kr, 19% N, and 1% HBr at 1 atmosphere, and sealed. The reaction vessel was placed in the isothermal section of the furnace and heated at 610°C for 500 hours. After cooling, open the reaction vessel, take out the test glass tube, plug one end and fill it with deionized water. The opposite end was then plugged, and the capsule tube was heated to 100°C for 1 hour to dissolve the water-soluble reaction product formed on the inner surface of the cylindrical capsule glass. The water in each capsule was then analyzed for bromine, calcium, magnesium, barium, strontium (one glass sample had a small amount of CaO replaced by SrO) and sodium. The results are listed in Table II.

Table II Concentration in original solution (mmol/L) illustrate Br Ba Ca Mg Sr Na 8253, SrO replaces part of CaO 0.390 0.036 0.083 0.000 0.062 0.019 GE180, product composition 0.388 0.109 0.060 0.000 0.004 0.007 8253, without ZrO ₂ and B ₂ O ₃ 0.348 0.023 0.146 0.000 0.001 0.010 8253D, Composition of products 0.319 0.020 0.135 0.000 0.002 0.011 8253, _ZrO2 -free 0.229 0.018 0.124 0.000 0.001 0.007 8253, less alkali product glass 0.189 0.008 0.061 0.000 0.000 0.006 1725, Composition of products 0.154 0.032 0.099 0.000 0.002 0.012 1724, Laboratory Melts 0.035 0.007 0.008 0.001 0.000 0.003 8253, MgO replaces part of CaO 0.034 0.007 0.009 0.001 0.000 0.003 1724, Composition of products 0.030 0.006 0.007 0.001 0.000 0.003 1720, Product composition [0.5 wt% base] 0.012 0.000 0.006 0.001 0.000 0.005 8253D, untreated with HBr [control] 0.002 0.000 0.004 0.000 0.000 0.002

Glass No. 8253 with MgO substituting part of CaO listed in Table II is one of the glasses of the present invention. It is found that the bromine reaction of this glass is much smaller than that of any other high temperature glass under the same test conditions. The lower temperature Glasses such as 1720 and 1724 have very little bromine contamination as they are used at low pressures. However, as mentioned above, these glasses cannot be used at high pressures because of the low deformation point of these glasses which would cause shrinkage of the structure , when the crack at the interface between the inner glass and the lead wire expands, it eventually causes non-passive damage to the lamp.

Other glasses of the invention were prepared as follows.

Example

When making the glasses of each embodiment, the alkaline substance used is slightly changed each time. For example, quartz sand, alumina, magnesium carbonate, calcium carbonate, and barium carbonate, and zircon sand. Cerium oxide and barium bromide can be added as needed. Put the well-mixed mixture into a Pt/Rh crucible and melt it in a laboratory at 1600-1650°C, then refine and homogenize. Pull it vertically in a laboratory stretcher. Glass is a small crystal without cracking. Table III lists the glass (A5) example according to the inventive solution and the comparative example (V1), the compositions based on the weight percent of oxides and their main properties.

In addition to transition temperature (Tg), re-foaming temperature is also listed. The re-foaming temperature is the temperature at which bubbles are suddenly formed at the interface of the metal (the fixture of the sample, that is, molybdenum) when the temperature rises for a glass sample without visible bubbles at room temperature. The higher the refoaming temperature, the less likely the glass will form bubbles when used to seal molybdenum. In the comparative example, a higher cooling point (UCP) occurs at Tg.

High-power tungsten-halogen lamps prepared in glass tubes by conventional methods were used for the lamp tests. These lamps operate continuously at a bulb temperature of 700°C. Determine the duration before the glass bulb starts to blacken. The test value of A5 is very good, while the V1 shows bulb swelling phenomenon.

Table III A5 V1 SiO ₂ 60.7 56.8 Al ₂ O ₃ 16.5 16.4 B ₂ O ₃ 0.3 4.7 MgO 5.7 5.8 CaO 7.8 7.8 SrO - - BaO 8.0 8.0 _ZrO2 1.0 - _CeO2 - - Br - - Na ₂ O 0.011 0.028 K ₂ O 0.006 0.018 H ₂ O [wt%] 0.01 0.017 Thermal expansion 20/300[10 ^-6 /k] 4.37 4.52 T _g [°C] 781 721(UCP) Re-foaming temperature [°C] 1490 nd

In addition, it is preferable that the total amount of alkaline earth oxide (RO) is not less than 21 wt%, but not more than 24 wt%. Outside this range, thermal expansion and viscosity values will deviate from the required values.

And the weight ratio of the total amount of CaO, SrO and MgO to BaO ((CaO+SrO+MgO)/BaO) should be between 1.45 and 1.75, preferably between 1.65 and 1.75.

The weight ratio of MgO to CaO is also believed to be important; therefore, MgO/CaO should always be greater than 0, preferably less than 0.8, otherwise the crystallization stability of the glass is not sufficient for glass tube drawing.

Compared with the above-mentioned prior art glasses for high pressure lamps, i.e. GE180, Corning 1725 or Schott8253 glasses (with binary alkaline earth oxides (BaO, CaO)), the ternary alkaline earth oxides (BaO, CaO, CaO) of the present invention MgO) mixtures have slower ion migration, so the present invention is considered to be superior to the prior art. In addition, the emphasis in the manufacture of the glass of the present invention also includes eliminating or reducing alkali impurities to a minimum. That is, the amount of sodium, lithium and/or potassium should be kept below 0.05 wt%. The invention thus provides a five-component aluminosilicate system (SiO ₂ , Al ₂ O ₃ , BaO, CaO, MgO) which is particularly superior to prior art glasses, i.e. on the inner surface of lamps operating under the halogen cycle There are no bromine reaction products, so they can operate longer, and, reducing or eliminating non-passive damage, the lamp will run cleanly until the normal end of lamp life.

There has been shown and described the preferred embodiment of the invention. Those skilled in the art will find that various changes and modifications can be made without departing from the scope of the present invention as defined by the appended claims.

Claims (4)

1. alkaline earth aluminosilicate glass, mainly form by following ingredients: with the weight percent meter of oxide compound, the SiO greater than 58 to 64wt% ₂, 14 to 17.5wt% Al ₂O ₃, 0 to 1wt% B ₂O ₃, 1 to 7wt% MgO, 5.5 to 14wt% CaO, 6 to 17wt% BaO, 0 to 1.5wt% ZrO ₂, the SrO from 0 to 8wt%, wherein, the total amount of alkaline earth metal oxide is not less than 21wt% and is not more than 24wt%.

2. by the glass of claim 1, wherein, (CaO+SrO+MgO)/the BaO weight ratio is between 1.45 and 1.75.

3. by the glass of claim 2, wherein, described weight ratio is between 1.65 and 1.75.

4. by the glass of claim 2, wherein, the alkali metal oxide content of described glass is less than 0.03wt%, and water-content is less than 0.02wt%.

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