KR19980043561A - How neon gas discharge lamps and pulses work - Google Patents

Abstract

A pulse structure for operating a neon lamp in a multicolor light source is described with a car light. The particular neon lamp is a mercury-free, low pressure rare gas lamp, which can be operated as a red, amber and potential white light source that is effective in automotive and other light applications. Preferred pulse structures induce sparks to ionize neon and generate ultraviolet radiation and have falling pulses to energize the lamp, which increases the visible neon emission efficiency.

Description

How neon gas discharge lamps and pulses work

The present invention relates to an electric lamp, in particular a discharge lamp. In particular, the present invention relates to a method for operating a low pressure rare gas discharge lamp.

In the past, color lamps were made by placing a color filter in front of a continuous spectrum tungsten filament lamp. Many of the available filters make most of the desired color possible. Unfortunately, tungsten filament lamps are not only inefficient, especially when filtered; Shorter life compared to discharge lamps. Discharge lamps are more efficient and have a longer life than tungsten filament lamps. For example, neon discharge lamps are currently used on a Ford Expolrer as a central high mounted stop lamp (CHMSL). The lamp has a 3.0 millimeter diameter, 5.0 millimeter outer diameter, low pressure neon fill and 47.10 cm arc gap. The lamp is driven by a 60kHz sine wave and generates 220 lumens with an efficiency of 8 lumens per watt. It withstands two thousand hours of operation and eight hundred thousand lights. A typical neon emission spectrum is shown in FIG.

The discharge lamp color is the result of specific atomic emissions and can only be adjusted by selecting various chemical compositions. Possible lamp colors are determined by a limited number of useful gases and phosphorus, where phosphorus is used. Not all colors are available and not all colors are made efficiently.

Thus, there is a need for a method of operating a discharge lamp that is efficient in operation and capable of color adjustment.

1 is a cross-sectional view of a phosphorescent coated neon lamp and pulsed power supply, partially cut away.

2 is a graph of emission spectra from neon vehicle lamps.

FIG. 3 is a subrange graph for energy transition states for neon showing vacuum ultraviolet energy transitions used to excite phosphorus at 74.4 and 73.6 nanometers.

4 is a comparative graph of the spectral output of a neon lamp with zinc silicate phosphorus operated in continuous waveform and pulsed formats.

5 is a comparative graph of the spectral output of a neon lamp with YAG phosphor operated in continuous waveform and pulsed format.

6 is a graph of chromaticity values of phosphorus coated and neon charged lamps for current pulses with various duty cycles.

FIG. 7 is a graph recording the desired current and voltage for electric pulses of YAG phosphorus coated neon lamps.

8 is a comparison graph of three current pulses with similar primary pulses and different secondary pulse widths.

9 is a graph of the relative neon emission rates of the main neon lines when the secondary pulse width is variable.

10 is a graph of comparison of emission data of neon lamps coated with YAG phosphor operating at different primary pulse widths.

11 is a comparative graph of spectral radiation of a YAG phosphor coated neon lamp using three different phosphor thicknesses.

12 is a circuit diagram of a 25 watt pulsed power supply for a neon, phosphorus coated lamp.

FIG. 13 is a graph of the comparison of the relative spectral difference between lamps with YAG and lamps with mixed YAG and red.

* Description of the symbols for the main parts of the drawings *

10 lamp 12 tubular outer shell

14 first electrode 22 gas filler

24: second electrode

A rare gas filled, phosphorus-coded, double-pot discharge lamp can be operated to provide a combined color by forming an input power pulse. The power pulse is selected to have at least a first portion before time and a second portion later than time, wherein the first portion has a pulse width selected to excite ultraviolet photon emission from the rare gas, The two parts have a pulse width selected to enhance the additional visible light output from the rare gas, or otherwise supply sufficient voltage and current to cause ionization of the lamp charge.

1 shows a partially cut, cross-sectional view of a preferred embodiment of a neon fluorescent lamp. The vehicle neon stop lamp 10 is assembled with a tubular envelope 12, a first electrode 14, a neon gas filler 22, a second electrode 24 and a phosphorus coating 26. The lamp is operated by a pulse generator 30.

The tubular sheath 12 may be made of hardened or softened glass or quartz to have an elongated tube of normal form. The choice of external material is important. Preferred glass does not become opaque or degassing at operating temperature and also prevents neon losses. Suitable glass is alumina silicate glass, ie cured glass, which is commercially available from Corning Glass Walkers and is known as type 1724. Applicants have found that the 1724 cured glass blocks almost all neon losses. The 1724 glass may be cured at 900 degrees Celsius to remove water and hydrocarbons. Fine cure helps to standardize the color produced and improves cleanliness which improves lamp life.

Typical neon sign lamps use low pressure (10 torr or less) and generate low intensity discharges at low brightness. The outer tube is made of lead or lime glass, which is easily formed into curved letters or shapes to create the desired sign. These glasses release the lead or other chemical species into the shell when operating at higher temperatures with stronger discharges. The glass becomes opaque or smeared, or the gas chemistry changes to alter the lamp color. The use of pure quartz is not entirely allowed because pure quartz has a structure that allows neon to diffuse. The neon loss from the sealed volume depends on the lamp temperature and the gas pressure, so for high pressure lamps more neon is lost, resulting in greater pressure and color change. There are additional optical and electrical changes that occur when neon losses increase.

The inner diameter 16 of the shell 12 can vary from 2.0 to 10.0 millimeters, with a preferred inner diameter 16 of about 3.0 to 5.0 millimeters. The lamp operates marginally at a diameter of 9 or 10 millimeters. It can be seen that at 5 millimeters the better results, 3 millimeters is the best internal diameter. The preferred skin wall thickness 18 can vary from 1.0 to 3,0 millimeters, the preferred thickness 18 can vary from 1.0 to 3.0 millimeters, and the preferred thickness 18 is about 1.0 millimeters. Outer diameter 26 can vary from 4.0 millimeters to 16.0 millimeters, with a preferred outer diameter 28 of 5.0 to 7.0 millimeters. The tubular sheath may be made from 12.7 centimeters to 127 centimeters (5-50 inches) in total length. The overall length for bright-field emission is a designer's option.

The tubular sheath 12 has one end at a first sealing end. The first sealing end has a first electrode 14. A preferred first seal end is a pressure seal that holds the first electrode 14 in a cured glass shell. At the opposite end of the tubular sheath 12 is arranged a second sealing end. The second sealing end has the same structure as the first sealing part and can be formed to hold the similarly formed second electrode 24. The lamp 10 is operated as a distilled liquor, so that the electrodes are separated to sufficiently form a distilled liquor discharge.

Electrode efficiency and electrode life are important for overall lamp performance. Preferred electrodes are cold cathode types with a material design that is expected to operate at high temperatures for long lamp life. The high temperature cathode or electrodeless lamp can be operated using the method of operation of the present invention. The molybdenum rod type electrode is formed to protrude into the sealed shell volume, and a cup is disposed and supported around the inner end of the electrode rod. The cup may be formed of nickel wound in the form of a cylinder. Tantalum rod or cup type electrodes are desirable in life.

The area between the electrode tip and the inner wall of the cup may preferably be coated or filled with a conductive material having a lower work function than the cup. The filler material is preferably an emitter composite with a low work function and may also be a getter. Preferred emitters are alumina and zirconium getter materials, known as Sylvania 8488, stretched and cured to provide a uniform coating. The cup wraps around the emitter tip and extends slightly more than the innermost part of the electrode rod to a 2.0 mm, tubular sheath, the emitter material extending. An emitter material or electrode material sputtered from the emitter tip is included in the elongated cup.

Preferred rare gas fillers 22 are neon with near pure research quality. Applicants have found that the purity of neon fillers and the cleanliness of the lamps are important in consistently obtaining a suitable lamp color. Mercury reduces the lighting voltage required for discharge lamps, but also adds a large amount of blue ultraviolet light to the output spectrum. Mercury lamps are also difficult to light in low temperature environments and are undesirable characteristics for vehicle lamps. Meanwhile, other gases such as argon, helium, krypton, nitrogen, radon, xenon and their compounds may be included in the lamp at low concentrations (almost pure). These gases quickly affect lighting conditions, operating conditions and output color. In general, these other gases have a lower energy band than neon, and therefore, even in small amounts, dominate the emission results or suppress the generation of neon visible ultraviolet light. Pure or nearly pure neon is thus a preferred neon lamp filler.

Gas filler 22 pressure affects the lamp color output. Increasing the pressure shortens the time between atomic collisions, shifting the luminescent populations to dark red. By adjusting the pressure, the lamp color can be affected. At pressures below 25 Torr, chromaticity is out of the SAE red region. At 70 Torr, neon gives SAE-permissible red with a chromaticity shape of (0.662, 0.326). At 220 Torr, the color still satisfies the SAE requirements, but shifted to dark red with a coordinate of (0.670, 0.324). As the pressure decreases, the emitted light tends to be orange.

Neon gas filler 22 may have a desired pressure of 20 to 220 Torr. At pressures of 10 Torr or less, the electrode can be sputtered to discolor the lamp, to reduce the functional output intensity, and to break the lamp by reacting the sputtered material with the skin wall. At pressures above 220 Torr, the ballast must provide a strong electric field to move the electrons through the neon, which is uneconomical. Lamps larger than 300 torr neon are not suitable due to increased hardware and operating costs. The effect of pressure depends in part on the lamp length (arc gap). The preferred pressure for a 30.48 centimeter (12 inch) lamp is about 100 Torr.

The lamp envelope is further coated with phosphorus 26 responsive to neon ultraviolet radiation lines. Several phosphorus are known and generally they are attached to the inner surface of the lamp envelope. They can be attached to other surfaces formed inside the shell. Most puppeteer minerals held in binders are potentially useful. Preferred phosphorus 26 for amber has an alumina binder and includes yttrium alumina cerium. Applicants use Sylvania type 251, the adjustment of which includes Y ₃ : A ₁₅ O ₁₂ : Ce. Applicants have also found that zinc silicate (zinc orthosilicate) phosphorus responds to neon ultraviolet radiation, but these are somewhat undesirable.

The thickness of the phosphors affects the lamp color, since the lamp emission is due to the visible emission from neon gas and phosphorus. An increase in phosphorus thickness increases phosphorus release up to the saturation point. At the same time, the increase in phosphorus thickness reduces the conduction of visible neon emission. Phosphorus thickness to some extent controls the relative amounts of the two emissions, thus controlling the combined color. Preferred phosphor coating thicknesses are determined by simple tests. 11 shows the results of the phosphorus coating thicknesses of 18, 36 and 50 microns, respectively, which are shown by curves 64, 66 and 68, respectively. The largest luminescence is obtained with a 36 micron coating.

The lamp is operated by pulse generator 30 to give neon red, or combined phosphorus and neon colors. The red mode can be achieved by providing a direct current or continuous wave alternating current power source. A pulsed mode power source is used to activate the phosphor and form the desired color through a mixture of neon and phosphorous emission. The present invention uses a circuit as in FIG. 12 to generate a pulse. By varying the characteristics of the device, the respective primary 46 and secondary 48 pulse widths are changed. The rise time and peak voltage of the voltage pulses for the lamp are the sum of the parasitic capacitance associated with the capacitor C6, the secondary winding of the transformer, the lamp and its wiring, and when Q2 is turned off, the current flowing in the primary is in parallel with the parasitic capacitance. Flow continues to capacitor C6. This results in a sinusoidal increase in voltage, which continues until the lamp is lit, in which the lamp exhibits low impedance between the outputs of the transformer. Next, the charge stored in the capacitor C6 and the parasitic capacitance is discharged through the lamp. The rise time of the current pulse is determined by the resistance value of the transformer winding, the leakage inductance on the secondary side of the transformer T1, and the total capacitance value. The discharge continues until the voltage of the capacitor C6 raised by the transformer T1 does not sufficiently maintain a current through the lamp which is larger than the energy stored in the transformer core can be maintained. In this regard, the energy stored in the transformer is transferred to the lamp so that the secondary current pulse is longer in duration than the primary pulse. The primary pulse time constant is controlled by the leakage inductance and winding resistance values, and the secondary current pulse time constant is controlled by the secondary inductance and ramp voltage. This generates a relatively long secondary current pulse for a very short primary current pulse.

The amount of energy contained in the primary pulse 46 for the secondary pulse 48 is determined by the amount of energy transferred from the transformer T1 to the capacitor before the lamp is turned on. By adjusting the value of C6 so that the lamp is lit at the point that all energy from the transformer is transferred to the capacitor, most of the energy is included in the primary pulse 46. Conversely, by adjusting the value of (C6) so that lamp lighting occurs before all of the energy is delivered to (C6), the secondary pulse 48 is dependent on the ratio of the energy stored in the capacitor to the energy stored in the transformer at the time of lamp lighting. Increase energy. Similarly, the energy of the secondary pulse is increased by adjusting (C6) so that lamp lighting occurs after all energy is transferred to the capacitor and energy is passed back to the transformer.

During the electrical discharge, neon gas is excited through the collision. For low pressure neons like a few torr, the average time between atomic collisions is long over the lifetime of the excited state. Applicants have found that under these conditions it is possible to control a relatively large number of atomic excited neon in various excited states through electrical excitation. The lamp color can be changed by changing the relative population in the selected state. In particular, it is possible to increase or decrease the visible radiation in the red range to ultraviolet radiation for phosphorus stimulation.

Applicants have found that lamp efficiency can be increased by 50 to 70 percent by electrically operating neon discharges in pulsed mode excitation. In addition to increasing lamp efficiency, Applicants also observed that lamp chromaticity changes due to a change in the relative intensity of the visible spectrum emission line. If the excitation pulse width is narrow, the color of the neon lamp is shifted from red to orange. It was believed that the amber light source emitted directly could be made by selectively supplying a pure neon light lamp with no phosphor. Such a neon lamp may be used on the rear of the vehicle to support a first power format for producing red light for a vehicle brake signal and a second power format for producing amber light for a turn signal. Direct amber emission by providing a pulse to neon without the use of phosphorus is not satisfactory.

Therefore, phosphor-coated neon lamps were studied. Temperature Limits Because of the automotive experience and the desire to limit possible environmental hazards, mercury is considered an undesirable filling component. Lamps with neon emission excited phosphorus have been studied.

Green emitting phosphorus can be used to mix with the red spectrum emission of neon to form an amber color. Zinc silicate (Zn ₂ SiO ₄ : Mn), green emission phosphorus, has been attempted. Zinc silicate was measured to have a quantum efficiency of 1.5 at an excitation wavelength of 74 nanometers and a neon resonant line. FIG. 3 shows a partial range graph of the energy transition states for neon I, which shows the vacuum ultraviolet energy transitions of 74.3 and 73.6 nanometers used to excite phosphorus.

4 is a comparative graph of the spectral output of a neon lamp with zinc silicate phosphorus operated in a continuous wave and pulse format. The lamp has a 100 tonne pressure neon filler, 25. 4 cm (10 inch) arc, 3.0 millimeter inner diameter and 5.0 millimeter outer diameter, and has a cylindrical glass shell in a cold cathode electrode configuration. Line 32 shows a stronger result with pulsed mode operation, and line 34 shows a weaker result with continuous wave mode operation.

In FIG. 4, the presence of phosphorus emission is evident, but recognizing the difference in the intensity of phosphorus emission when the lamp is excited by an electric pulse (line 32) compared to a sinusoidal continuous wave cw (line 34) It is important. Electrically, the pulse stimulates phosphorus better than sinusoidal operation. Similar zinc silicate-neon lamps operate for up to 4000 hours with little change in color over their lifetime. Various pulse widths and frequencies are experimentally tested. Neon lamps using one of two zinc silicate phosphors, Sylvania 2288 and 2282, can produce amber light that meets SAE specifications. Lamps using such phosphorus are not as efficient as lamps coated with YAG phosphors (Sylvania 251 and 157). Neon lamps using these two different zinc silicate phosphors, Sylvania 1643 and 2283, do not produce a suitable amber color. Nevertheless, the result confirms the concept of adjusting the lamp output color by changing the pulse shape. Lamps made from a combination of zinc silicate and yttrium get this exact amber color.

Ultraviolet emission of atomic neon has discontinuous emission lines between 335 and 375 nanometers, and peak intensities at about 347 and 359 nanometers. These lines have a significantly smaller intensity than some strong visible neon lines. In order to take advantage of such ultraviolet emitting lines, there is a need for green phosphorus that can be excited by these lines. Peak excitation at 341 nm selects YAG phosphorus (yttrium, alumina, garnet) (sylvania 251), which outputs green and provides chromaticity values of X = 0.431 and Y = 0.551. The chromaticity satisfies the SAE standard.

Color mixing calculations are made based on these chromaticity values, and chromaticity values of atomic ions exhibiting amber color are possible. An experimental neon lamp was made and tested. The basic configuration of the lamp is the same as that of zinc silicate-neon lamps. This was driven by a 60 kHz sine wave (cw) and a direct current pulse. The pulses used are the same as those used to excite the zinc silicate-ion lamp of FIG.

5 shows a comparison graph of the spectral output of a neon lamp with YAG phosphor operated in continuous wave and pulse format. 5 displays that pulse provision (line 36) stimulates phosphorus better than continuous wave excitation (line 38). The chromaticity values change for both types of electrical excitation. Pulsed operation produces a chromaticity value of X = 0.590 Y = 0.410, while continuous wave operation provides a chromaticity value of X = 0.646 and Y = 0.349. The lamp color is present in the amber region of the pulse value CIE chromaticity diagram. Pulsed neon lamps generate about 115 lumens at a lamp power of 7.2 watts. Several amber neon pulse systems were tested for life, operated and evaluated at 7 watts. After 1 million lightings, the lamp did not show any phosphorus or color damage.

Spectral data is collected on the lamp in the ultraviolet region to determine the cause of the phosphorous emission that changes under continuous wave excitation compared to pulsed excitation. Based on accurate spectral measurements, neon discharges produce nearly identical near ultraviolet radiation when operated under continuous wave or pulse excitation. Near-ultraviolet radiation from neon lamps causes a small level of excitation in phosphorus; However, there is no spectral emission difference in phosphorus under varying pulsed electrical operation.

The Society of Automotive Engineers (SAE) says that an amber turn signal system must develop at least 200 candelas in horizontal-vertical (HV). In general, every 10 lumens generated in a normal neon lamp can be changed to about one (1.0) candela. Using an average mechanically polished metallized aluminum parabolic reflector with an average focus for a small vehicle housing, an average candela gain of 10 can be obtained in horizontal-vertical. The actual operating power for neon lamps is about 23 to 25 watts.

6 is a graph of chromaticity values for phosphorus coated and neon charged lamps for current pulses with different duty cycles. By changing the duty cycle of the current pulse, the color of the lamp can be adjusted. Low pressure, 25.4 cm in coated neon lamps operate between 6 and 10 watts and with different pulse widths. The result is a string of different chromaticity points for different pulse widths. If the pulse is narrow, the color of the lamp becomes more yellow or green. FIG. 6 also shows the European (ECE) range (reference 42) and the US (SAE J 578) range (reference 44) defining the accepted automotive chromaticity standard (area) for amber light.

FIG. 7 is a graph showing the preferred current and voltage for electrical pulses in a coated neon lamp that is 30.48 cm (12 inches), 100 Torr pressure, YAG operating at about 15 watts. The entire pulse can be observed as two pulse overlays. The first portion, primary pulse 46, is high but has a narrow peak, which is faster than time. The second portion, secondary pulse 48, has a significantly lower peak some time later than time, but it extends over a long period of time. The pulse width can be defined as the width for a point on both sides with half the peak amplitude value about the peak.

In order to distinguish the results of the primary pulse 46 and the secondary pulse 48, an experiment is performed, where the width of the primary pulse 46 remains constant and the width of the secondary pulse 48 is changed. Some forms of these current waveforms are shown in FIG. 8. 8 is an overlay of three pulses, each having the same primary pulse 46, but with progressively wider secondary pulses 50, 52, 54.

Primary pulse 46 is the result of lamp diameter, fill gas, fill gas pressure, and electrode. The primary pulse 46 is designed to ionize the lamp so that electrical conduction occurs and sufficient neutral (ground state) neon atoms to energize to the first energy level. Neon may emit ultraviolet radiation, which in turn causes phosphor 26 to emit visible light. Primary pulse 46 is selected to efficiently stimulate phosphorus 26 to emit visible light. Insufficient primary pulses 46 fail to light, but too large primary pulses cause excessive electrode damage, electromagnetic lamp noise and similar problems. Under this constraint, the designer has the opportunity to design the primary pulse 46.

Secondary pulse 48 is selected to stimulate the neon filler to emit visible light. If the secondary pulse width is insufficient, there is a lack of visible neon red, so the lamp color is dominated by stimulated phosphorus emission, for example yellow or green. If the secondary pulse is too long, the lamp color is dominated by visible neon red. Because of the emission period and spatial separation, and depending on the timing between the primary pulse 46 and the secondary pulse 48, a real time delay occurs between several color emissions. The lamp flashes initially in yellow or green, then very briefly in neon red. (Also, emission redundancy can occur.) Since these separate emissions occur faster than can be perceived by the naked eye, they are integrated by the human eye in one color. In particular, green and red are integrated to form amber.

Since the phosphorus stimulus is the result of ground state neon atoms energized to an appropriate level, after the secondary pulse 48 passes, the neon must be fully discharged to return back to the ground state. The off (or low stimulus) period comes after the secondary pulse 48. The off (or low stimulus) period must be long enough so that at least 50 percent of neon reaches before the next primary pulse 46 occurs. (Otherwise, the neon is in a high excited state, limiting the generation of UV.) A sufficient return of neon to the ground state can be attained by an off cycle of several microns or more. The minimum off time depends on the degree of initial excitation, group level, statistical decay and other factors. If the off period is too large, the lamp will blink undesirably, so the off period should be at least about 30 microns.

Experiments of keeping the primary pulse 46 constant and widening the secondary pulses 50, 52, 54 show important results. The visible component of the lamp emission by phosphorus does not change, and the visible component by direct neon emission is changed. When the secondary pulse 48 is widened, the lamp output wattage amount (or operating power) is increased, which becomes brighter. However, since phosphorus emission remains constant despite the increase in power of the secondary pulse 48, the phosphorus excitation is independent of the secondary pulse 48. As a result, the ratio of this emission intensity to the neon emission intensity is changed.

FIG. 9 shows a graph of the ratio of relative emission from 703 and 824 nanometer lines and relative emission from 638 to 693 nanometers taken from original spectral data. The upward line 56 shows the ratio of the emission intensity between the 703 and 724 nanometer lines when the secondary pulse 48 is widened. The downward line 58 shows the ratio of the emission intensity between the 638 and 693 nanometer lines when the secondary pulse 48 is widened. The graph shows that as the width of the secondary current pulse 48 increases, the populations 703 and 638 increase for matched pairs 698, 724. The graph also shows that as the secondary pulse 48 becomes wider, the emission intensity from the 638/693 line (line 58) increases faster than the emission intensity from the 703/724 line (line 56). This increase is extended by the fact that the 638/693 line group has a high weight in human sense for the 703/724 line group. Lines 56 and 58 show that it is possible to increase the overall efficiency of neon red emission by widening the secondary current pulse 48. In both cases, as the width of the secondary pulse 48 increases, the relative intensity of the low emission line 58 increases, making the emitted light more orange. During this same increase in secondary pulse 48 width, no further phosphorus emission increases. If red (703 nanometer line) increases, orange (638 nanometer line) increases a lot, and green (phosphorus emission) does not change, chromaticity (amber) changes.

Similar experiments are performed on the primary pulse 48. 10 is a comparative graph of emission data from coated neon lamps that are YAG operated with different primary pulse widths. The data is normalized to 100% neon 703 lines. While widening the primary pulse 46, the width of the secondary pulse 48 remains constant at several microns. The spectral intensity for the narrowest primary pulse is shown by line 60. More emission is generally shown with shorter wavelengths (here green). The result for the widest primary pulse is shown by line 62. As a result, it is generally shown that narrow primary pulse 46 does not change red emission from neon, but increases orange color. 10 shows that the normalized phosphorus emission depends on the width of the primary pulse 46. The narrower the primary pulse 46, the greater the intensity of normalized phosphorus emission. Normalized decrease in red and normalized increase in orange and green are desirable for amber formation.

The 703nm neon line provides metastable levels of neon atoms. Increasing the metastable population may cause reabsorption of 703 nanometer emissions. However, line 724 terminates at a level with a transition allowed at 74.3 nanometers. An increase in the metastable population does not contribute to the absorption of 724 nanometer emissions.

FIG. 11 shows a comparative graph of spectral emission from a similar neon lamp with three different coating thicknesses of YAG phosphorus. Lamp emission light is a combination of visible phosphorus and gas emission. The graph shows that as phosphorus coating thickness increases for the same pulse excitation, phosphorus emission increases slightly but saturates between 36 and 50 nanometers. The absorption of visible neon emission also increases. Because of the absorption of visible neon emission, neon lamps can hinder the overall efficiency by thicker coatings. On the other hand, a power supply (ballast) may no longer be required to generate such a relatively narrow pulse to generate the same amber color as compared to a thin coating.

Pulse ballasts are designed to deliver 25 watts in 16-inch, 3mm ID x 5mm OD, 100 tonne neon and encoding lamps. The ballast produces a narrow primary pulse 46, with little or no secondary pulse 48 at 25 kHz. This ballast allows the neon lamp system to generate 360 lumens (15.65 lumens per watt) at 23 watts with chromaticity values of X = 0.572 and Y = 0.418. 12 shows a circuit diagram of a ballast providing pulse power with a 25 watt neon lamp.

In order to produce a European car amber lamp, the chromaticity value of the lamp must meet the European (ECE) amber standard. As indicated in Fig. 6, neon lamps with YAG phosphorus do not meet the ECE standard. The ramp output deviates slightly from the ECE color specification (area 42) by about 0.002 in the X-chromatic coordinates. There is a slight lack of red in the X color coordinates. The lamp is therefore slightly orange.

A way to produce a darker red color is to add red phosphorus to the phosphor coating of the neon lamp. Red phosphorus (sylvania type 236, magnesium flulogerate: manganese) with excitation between 300 and 350 nanometers and basic chromaticity values of X = 0.742 and Y = 0.291 is selected. Several mixtures were tested experimentally and found to be optimal mixing ratios of 10% red and 90% green (YAG) phosphorus. By this ratio, the red and green phosphorus coated on the neon lamp with neon red emission produces lamp chromaticity values X = 0.589 and Y = 0.407 under narrow pulse excitation. The value falls within the SAE and ECE specifications. FIG. 13 shows a graph of the relative spectral differences between YAG (green) lamps (line 80) and YAG and Sylvania 236 type (green and red) mixed phosphorus lamps (line 82).

Neon lamps can be efficient vacuum ultraviolet emitters when electric pulses are provided. Vacuum ultraviolet radiation emitted by neon discharge can be used as an efficient source for phosphorus excitation. Phosphorus coated neon lamps can be operated as amber light sources for automotive lights. A 40.64 cm (16 inch) low voltage neon lamp operating at 23 watts of pulse power can produce an efficient 15.65 lumens per watt, with chromaticity values of X = 0.572 and Y = 0.418.

In summary, the optimum pressure to meet the SAE amber chromaticity is 20 to 220 Torr, depending in part on the lamp length. The optimum pressure for electrical efficiency should be as small as possible, and the optimum pressure for sputtering control should be at least 50 Torr, preferably 70 To 150 Torr. The optimal frequency for candela efficiency is 12 to 17 kHz for a 25 cm (10 inch) long lamp. Sufficient amount of energy must be supplied during the selected duty cycle to ionize the lamp, with a sharp crest at the supplied primary pulse being preferred. The present invention has a crest factor of 1.41 or more. Crest rates of 4 to 8 are efficient, and higher crest rates have better results for phosphorus stimulation. The optimal actual system frequency is just above the human audible limit or about 20 kHz. The optimal primary pulse width for candela efficiency is less than 400 nanoseconds, preferably between 100 and 300 nanoseconds. Although generating short primary pulses is more efficient for stimulating phosphorus, obtaining short pulses is electrically more difficult. Amber light can be generated from only the primary pulse and no secondary pulse is required. However, this manner of operation is inefficient.

Lamp power is increased by using long secondary pulses, which leads to more neon red. Applicants have found that secondary pulses of 5 to 15 microns (5,000 to 15,000 nanoseconds) are more efficient when directly producing visible red light. Balancing between the primary and secondary pulses provides the selected phosphorus. The shorter the primary pulse, the more phosphorus is stimulated (green); This allows for a longer, more efficient secondary pulse (red). The lamp can be designed to have the shortest possible primary pulse, and the secondary pulse can be selected to balance the in output to provide the desired color. Optionally, the lamp can be designed to produce the most efficient light from the secondary pulses, thus selecting the primary pulses and phosphorus to balance the last color output. An intermediate state is also possible.

The optimal off period that allows the secondary pulse is long enough for the neon to fully return to neutral ground, so the next primary pulse can adequately provide a low energy level for the next UV emission. A few microns is enough.

Some dimensions in the working embodiment are approximately as follows. The tubular sheath is made of 1724 hardness glass and has a tube wall with a total length of 50 cm, an inner diameter of 3.0 millimeters, a wall thickness of 1.0 millimeter, and an outer diameter of 5.0. In addition, a lamp with 5.0 millimeter inner diameter and 7.0 millimeter outer diameter was made. The electrodes are made of molybdenum shafts which are crimped and supported on nickel or tantalum cups. Each nickel cup is coated with an alumina and zirconium getter material known as Sylvania 8488. Molybdenum rods have a diameter of 0.508 millimeters (0.020 inches). The outer end of the molybdenum rod is welded to the thicker (about 1.0 millimeter) outer rod. The inner end of the outer rod extends into a sealed tube about 2 or 3 millimeters. Thicker outer rods are more resistant to bending than thin inner electrode support rods. The cup lips extend about 2.0 millimeters more towards the shell than the rods.

The inner surface of the shell is coated with yttrium, alumina and cerium phosphorus. The gas filler is pure neon and has a pressure in the range of 20 to 220 Torr, preferably about 100 Torr. The lamp operates at about 21 watts and produces 360 lumens at 17.14 lumens per watt. The lamp light has an amber color with X = 0.572 and Y = 0.418 whose chromaticity values meet the SAE amber requirement. The foregoing operating conditions, dimensions, configurations and embodiments are merely examples, and other suitable configurations and relationships may be used to carry out the present invention.

While shown and described with respect to preferred embodiments of the invention, those skilled in the art can make various modifications and changes without departing from the scope of the invention as defined by the appended claims.

The present invention has the effect that the operation of the discharge lamp is efficient and color adjustment is possible.

Claims (30)

In a method of providing a pulse to a rare gas-filled phosphorescent coated discharge lamp, Providing pulsed power to the sealed gas filler, the pulse having at least a first portion before time and a second portion after time, wherein the first portion excites ultraviolet photon emission from the rare gas. Has a pulse width selected for enhancing the second portion, and the second portion has a pulse width selected for enhancing further light output from the rare gas; And Providing sufficient voltage and current to ionize said lamp filler. The method of claim 1 wherein the rare gas comprises pure neon. 1. A method of filling a rare gas filled and pulsed phosphorus coated phosphor discharge lamp, wherein Providing pulsed power to the sealed gas filler, the pulse having at least a first portion before time and a second portion after time, wherein the first portion excites ultraviolet photon emission from the rare gas. Has a pulse width selected for enhancing the second portion, and the second portion has a pulse width selected for enhancing further light output from the rare gas; Providing sufficient voltage and current to ionize the lamp filler; And Causing a low stimulation period to follow the pulse to return at least 50 percent of the gas filler to a ground state. 4. The method of claim 3, wherein the rare gas comprises pure neon. A method of operating a phosphorus coated gas discharge lamp with a filler component, a) providing pulsed energy with at least a first portion that stimulates the sealed filler component in the ground state to emit ultraviolet light such that the phosphorus coating emits visible light, b) providing at least a second portion stimulating a filler component to emit visible light by said pulsed energy; c) causing a low stimulation period to follow the pulsed energy to return at least 50 percent of the gas filler to ground; And d) repeating steps a, b and c at a speed as high as visually integrating the entire visible emission into one signal without flashing of the output color. 6. A method according to claim 5, wherein the period of the second portion is adjusted to change the relative visible emission from the filler component with respect to the visible emission from phosphorus, thereby adjusting the output color. 6. The method of claim 5 wherein the filler component comprises pure neon. 6. The method of claim 5, wherein the first pulse portion has a pulse width less than 400 nanometers. 9. The method of claim 8, wherein the first pulse portion has a pulse width between 100 and 300 nanometers. 6. The method of claim 5, wherein the second pulse portion has a pulse width between 100 and 1500 nanometers. 6. The method of claim 5, wherein the low stimulation period after the second pulse portion has a period of at least 1 micron second. 12. The method of claim 11, wherein the low stimulation period following the second pulse portion has a period of 30 microns or less. A method of providing a pulse to a discharge lamp in which pure neon is charged and phosphorus coated, Providing pulsed power to the sealed neon, the pulse having at least a first portion before time and a second portion after time, the first portion having at least one lamp at a first emission frequency. Has a pulse width selected to excite ultraviolet photon emission with sufficient energy to ionize the filler component, the second portion having sufficient energy to ionize a portion of the lamp filler at a second emission frequency; And Providing sufficient voltage and current to ionize the lamp filler. A method of operating a rare gas discharge lamp filled with pure neon and coated with phosphorus, Providing pulsed power to the sealed neon, the pulse having at least a first portion before time and a second portion after time, the first portion having at least one lamp at a first emission frequency. Has a pulse width selected to excite ultraviolet photon emission with sufficient energy to ionize the filler component, the second portion having sufficient energy to ionize a portion of the lamp filler at a second emission frequency; And Shifting a relative time balance between the time period of the first component and the time period of the second component; And Providing sufficient voltage and current to ionize the lamp filler. In the discharge lamp system, a) a light transmissive sheath forming an outer and sealed volume; b) at least two electrodes sealed to the envelope providing electrical connection from outside the lamp to the sealed volume; c) pure neon gas filler disposed in the sealed volume; d) phosphorus contained in the sealed volume; And e) a power source providing pulsed power; At least some of the pulses comprise a primary pulse portion sufficient to ionize a lamp and stimulate at least a portion of the sealed neon filler to a first energy state such that the first energy state is followed by a low off period upon stimulation. And a long period of time to return half of to a neutral ground state. 16. The method of claim 15, wherein the power supply supplies a secondary pulse in time between the primary pulse and the off period, the secondary pulse having sufficient voltage and current to stimulate neon to emit visible light. Discharge lamp system. 16. The discharge lamp system of claim 15, wherein said phosphorus is a green emitting phosphorus. 18. The discharge lamp system as recited in claim 17, wherein said phosphorus is zinc silicate phosphorus. 18. The discharge lamp system as recited in claim 17, wherein said phosphorus is YAG phosphorus. 17. The discharge lamp system of claim 16, wherein the phosphorus is a compound of green emitting phosphorus and red emitting phosphorus. 21. The discharge lamp system as recited in claim 20, wherein said phosphorus is a mixture of YAG phosphorus and red emitting phosphorus. 22. The discharge lamp system of claim 21, wherein the phosphorus is a mixture of about 90 percent YAG phosphorus and about 10 percent red emitter. 22. The discharge lamp system as recited in claim 21, wherein said phosphorus is a mixture of Sylvania type 236 red emitting phosphorus, YAG phosphorus. 16. The discharge lamp system as recited in claim 15, wherein said first portion has a period of 400 nanoseconds or less. 25. The discharge lamp system as recited in claim 24, wherein said first portion has a period of 100 to 300 nanoseconds. 16. The discharge lamp system as recited in claim 15, wherein said second portion has a period of 15.0 microns or less. 27. The discharge lamp system as recited in claim 26, wherein said second portion has a period of 5.0 microns. 16. The discharge lamp system as recited in claim 15, wherein said off period has a period of at least 1.0 micron seconds. 29. The discharge lamp system of claim 28, wherein the fraud off period has a period of 30.0 microns or less. In the discharge lamp system, a) a light transmissive sheath forming a wall with an inner surface forming an outer and sealed volume; b) at least two electrodes sealed to the envelope providing electrical connection from outside the lamp to the sealed volume; c) rare gas fillers disposed in the sealed volume to provide ultraviolet and visible light emission; d) phosphorus stimulated by the ultraviolet radiation and coated on the inner surface, the phosphor having a thickness selected to balance color of direct visible emission from phosphorus and transmitted visible emission from the rare gas; ; And e) a power source for providing power to the lamp electrode; The low source comprises a first power portion that stimulates at least a portion of the sealed rare gas filler to emit ultraviolet light and a second power portion that causes at least a portion of the sealed rare gas to emit visible light Discharge lamp system.