CN1222248A - Multiple reflection electrodeless lamp with sulfur or selenium fill and method of radiating therewith - Google Patents

Abstract

The present invention provides a method in which light in a sulfur or selenium lamp is passed through a fill multiple times to convert ultraviolet radiation to visible light. The light emitting device includes an electrodeless bulb, a light reflective coating surrounding a first portion of the bulb, the coating not bursting due to differential thermal expansion, and the bulb having a second portion containing light transmissive apertures.

Description

Multiple reflection electrodeless lamp with sulfur or selenium fill and method of radiating therewith

This application is a continuation of US Application Serial No. 08/656,381, filed May 31,1996.

The present invention is directed to an improved method of producing visible light and improved bulbs and lamps for providing such light.

US Patent Nos. 5,404,076 and 5,606,220 and PCT Publication WO 92/08240, incorporated herein by reference, disclose lamps for providing visible light using sulfur and selenium based fills. Pending US Application Serial No. 08/324,149, filed October 17, 1994, also incorporated herein by reference, discloses a similar lamp for providing visible light using a tellurium-based fill.

These prior art sulfur, selenium and tellurium lamps provide light with a good color rendering index at high efficacy. Additionally, the electrodeless formation of these lamps has a very long lifetime.

Most practical sulfur, selenium and tellurium lamp embodiments require a rotating bulb to work properly. This is disclosed in PCT Publication No. WO 94/084309, which states that, without rotating the bulb, isolated or filamentary discharges are produced which do not substantially fill the interior of the bulb.

The rotational requirements commonly found in the prior art introduce certain complicating factors. Therefore, the bulb is rotated by a motor which has the potential to fail and this is a limiting factor on the life of the lamp. In addition, additional components are required, thereby complicating the manufacture of the lamp and requiring more spare parts to be kept on hand. Accordingly, it would be desirable to provide lamps which give the advantages of the original sulfur, selenium and tellurium lamps, but which do not require rotation.

PCT Publication No. WO 95/28069 discloses a Dewar lamp intended to remove spin. However, one problem with this Dewar configuration is that it utilizes peripheral and center electrodes that are plated on the bulb, and the center electrode is prone to overheating.

The present invention provides a method of producing visible light, and bulbs and lamps used in the method that eliminate or reduce the need for rotating the bulb.

The present invention gives greater design flexibility in providing bulbs with smaller dimensions than the prior art and/or utilizing active materials with lower densities of sulfur, selenium and tellurium fills, which is still able to provide Primary visible light output. For example, this facilitates the supply of low-power lamps, which facilitates the use of smaller bulbs. This feature of the invention can be used in conjunction with other features, or independently. For example, the smaller bulb may be provided without rotation, or with rotation.

According to a first aspect of the present invention there is provided a method utilizing a lamp fill which, when energized, contains at least one substance selected from sulfur and selenium; energizing the lamp fill to Said sulfur or selenium is caused to generate radiation containing a considerable spectral power component in the ultraviolet region of the spectrum, and a spectral power component in the visible region of the spectrum, which is reflected much more through the filling in the contained space Second, thereby converting part of the radiation in the ultraviolet region of the spectrum to radiation in the visible region of the spectrum, which is more visible radiation than it would be if reflection occurred without conversion. Finally, visible radiation is emitted from the contained space.

According to another aspect of the invention, the filling is excited such that sulfur or selenium produces a spectral power component in the ultraviolet and a spectral power component in the visible region, wherein the multiple reflections result in a reduced ultraviolet spectral component of at least greater magnitude than the original Portions are 50% smaller.

In PCT Publication No. WO 93/21655, sulfur and selenium lamps are disclosed in which light is reflected back into the bulb to lower the color temperature of the emitted light, or to make it more closely resemble black body radiation. Unlike the present invention, in prior art systems, it is radiation with a substantial visible (or higher) spectral output that is reflected to produce another visible spectral output that is in the red More spectral power in the light region. The difference from the prior art is that in the present invention the reflected radiation has a substantial spectral power component in the ultraviolet region (i.e. at least 10% of the combined spectral power of ultraviolet and visible light), a portion of which is converted into visible light. It is this conversion of UV to visible light by multiple reflections in the present invention that allows smaller bulbs to replace larger bulbs and/or use lower density active materials, allowing stable operation without rotating the bulb.

Because the method of the present invention involves multiple reflections of the light through the filling and finally out, it is contemplated to use a bulb having a reflector layer around the quartz except for the small aperture through which the light passes shoot out. Such "aperture lamps" are known in the art and an example is shown in US Pat. No. Re34,492 to Robers.

The Roberts patent discloses an electrodeless spherical housing having a reflective coating except for the apertures aligned with the light guide. However, it has been found that the structure of Roberts is not suitable for carrying out the method of the present invention, as applied in normal commercial use. This is because it uses a coating on top of the lamp envelope. When the bulb heats up in use, the different coefficients of thermal expansion of the quartz envelope and the cladding cause the cladding to crack. Therefore, the life of the bulb is very limited. Also, coatings are generally not thick enough to provide the magnitude of reflectivity required for adequate wavelength conversion from ultraviolet to visible light.

According to one aspect of the invention, these problems are solved by using a diffuse reflective ceramic covering for the bulb, which is in contact with the envelope at least at one point and which does not crack due to differential thermal expansion. In a first embodiment, the cover layer comprises a sleeve, different from the cladding, which is not attached to the bulb. Also, the jacket is made thick enough to provide a high enough reflectivity to perform the desired wavelength conversion. In a second embodiment, the cover of the reflector bulb is made of the same material as the bulb, so that there are no problems due to differential thermal expansion. In this embodiment, the cover layer may also take the form of a non-attached casing. In yet another embodiment, a diffuse reflective powder is provided between the envelope and the bulb.

The invention will be better understood by reference to the accompanying drawings, in which:

Figure 1 shows a prior art lamp with a filling based on sulfur, selenium or tellurium;

Figure 2 shows a small hole lamp;

Figure 3 shows a light bulb without electrodes according to an embodiment of the present invention;

Figures 4 and 5 show a special configuration;

Figures 6 to 8 illustrate other embodiments of the present invention;

Figures 9 and 10 illustrate the use of diffusion holes;

Figures 11 to 13 show other designs of diffusion holes;

Figures 14 to 16 illustrate other embodiments of the present invention;

Figure 17 shows a normalized spectral comparison between covered and uncovered bulbs of an embodiment of a microwave lamp;

Figure 18 shows a spectral comparison between covered and uncovered bulbs of an embodiment of a microwave lamp;

Figure 19 shows a normalized spectral comparison between covered and uncovered bulbs of embodiments of R.F. lamps;

Figure 20 shows a spectral comparison between covered and uncovered bulbs of an embodiment of an R.F. lamp.

Referring to Figure 1, a prior art lamp is depicted having a fill which, when energized, contains sulfur, selenium or tellurium. As described in the above-mentioned patents incorporated herein by reference, the light provided is molecular radiation primarily in the visible region of the spectrum.

The lamp 20 includes a microwave resonator cavity 24 consisting of a metallic cylindrical part 26 and a metal mesh 28 . The mesh 28 allows light to escape from the cavity while retaining most of the microwave energy inside it.

A bulb 30 is disposed in the cavity, which in the depicted embodiment is spherical. The bulb is supported by a rod which is connected to a motor 34 to rotate the bulb. The rotation facilitates stable operation of the lamp.

Microwave power is generated by the magnetron 36 and the waveguide 38 transmits this power into a gap (not shown) in the cavity wall, from which the power is coupled to the cavity, in particular to the filling in the bulb 30,

The bulb 30 is composed of a bulb and a filler in the bulb. In addition to containing inert gases, the filling contains sulfur, selenium or tellurium. For example, InS, As ₂ S ₃ , S ₂ Cl ₂ , CS ₂ , In ₂ S ₃ , SeS, SeO ₂ , SeCl ₄ , SeTe, SCe ₂ , P ₂ Se ₅ , Se ₃ As ₂ , TeO, TeCl ₅ , TeBr ₅ , TeBr ₅ and TeI ₅ . Other compounds that may be used are those having a sufficiently low vapor pressure at room temperature, ie, solids and liquids, and those having a sufficiently high vapor pressure at operating temperatures to provide useful illumination.

Prior to the sulfur, selenium and tellurium lamps of the invention described above, the molecular spectra of these substances produced by lamps in the prior art were believed to be predominantly in the ultraviolet region. In the process carried out by the sulfur, selenium and tellurium lamps described with reference to Figure 1, the radiation initially provided by the elements sulfur, selenium and tellurium (referred to herein as "active material") is similar to that of prior art lamps, That is, mainly in the ultraviolet region. However, as the radiation passes through the filling on its way to the bubble wall, this radiation is primarily converted to visible radiation by the process of absorption and re-radiation. The amount transferred is directly related to the optical path length, ie, the density of the active material in the fill multiplied by the diameter of the bulb. If smaller bulbs are used, then higher densities of active materials must be provided to efficiently produce the required visible radiation, whereas if larger bulbs are used, lower densities of these substances can be used.

According to one aspect of the invention, the optical path length is substantially increased without increasing the diameter of the bulb by reflecting the radiation multiple times through the fill after it initially passes through the fill. In addition, the density of the active material and the size of the bulb are small enough that the radiation that initially passes through the filling and is being reflected can have a spectral power component in the ultraviolet region. That is, without multiple reflections, the spectrum emitted from the bulb is unacceptable to us in visible light applications. However, due to multiple reflections, the UV radiation is converted to visible light, which produces a better spectrum. Multiple reflections across the fill allow the use of a smaller density of active material, providing an acceptable spectrum for any given application. Also, a less dense filler has less electrical impedance, which in many embodiments provides better microwave or R.F. coupling to the filler. Working with this less dense active material promotes stable operation, even without bulb rotation. Additionally, the ability to use smaller bulbs increases design flexibility and, for example, facilitates supplying lower wattage lamps. As used herein, the term "microwave" refers to a higher frequency band than that of "R.F."

As mentioned above, since the method of the present invention requires multiple reflections through the filling before the light is emitted to the outside, it is contemplated to use a bulb having a reflective layer on it except for a small hole through which the light emerges. A lamp of this type (disclosed in RE 34,492 to Robert et al.) is shown in FIG. 2 . Referring to FIG. 2 , a spherical glass bulb or bulb 9 (which is typically made of quartz) contains a fill 3 forming a discharge. The glass bubble has a reflective layer 1 on the entire surface except for the small hole 2 which is aligned with the light guide 4 .

However, as noted above, Robert's construction was found to be unsuitable for practicing the method of the present invention because it uses an inherently attached coating (which is different from the material of the bulb). When the bulb heats up in typical commercial applications, the different coefficients of thermal expansion of the quartz glass bulb and the cladding cause the cladding to crack. Therefore, the lifetime of the device is very limited. Also, typically the coating is not thick enough to provide the amount of reflectivity required to provide proper wavelength conversion from ultraviolet to visible light.

Referring to Figure 3, an embodiment according to the present invention is described which solves these problems. The bulb 40 encased in a filling 42 is surrounded by a reflective sheath 44 which is not attached. The jacket is made thick enough to provide high enough UV reflectivity for the desired wavelength conversion. Between the bulb and the envelope there is an air gap 46 which can be on the order of a few thousandths of an inch. The sleeve contacts the bulb at a minimum of one location, and may contact the bulb at multiple locations. There is an aperture 48 through which the light exits. Since the envelope is not attached to the bulb, differential thermal expansion at operating temperature can be accommodated without breaking the envelope.

According to another embodiment of the present invention, a diffuse reflective powder such as alumina or other powder may be used to fill the gap between the envelope and the bulb. In this case, the gap can be wider.

According to yet another embodiment of the invention, the reflective cover of the bulb is made of ceramic, which is made of the same material as the bulb. Therefore, there is no problem of differential thermal expansion. Such a covering can also be constructed so as not to adhere to the bulb.

In one method of forming the envelope, the sintered body is produced directly on the spherical bulb. It starts as a powder, but is heated and pressed to form a sintered solid. Since it's not attached, it falls apart when the casing breaks. Suitable materials are powdered alumina and silica, or combinations thereof. The casing is made thick enough to provide the desired UV and visible reflectivity as described herein, and it is typically thicker than 0.5 mm up to about 2 to 3 mm, which is much thicker than the coating.

The structure of the case will be described with reference to FIGS. 4 and 5 . In this case, the casing and the bulb are formed separately. The quartz bulb is blow molded into a spherical shape, which results in a bulb with dimensionally controlled OD (outer diameter) and wall thickness. Fit the fill tube onto the bulb bulb when molding. For example, a 7mm OD and wall thickness 0.5mm, and filled with 0.05mg of Se and 500Toor of Xe inductively coupled equipment work. The fill tube is removed so that only the short overhang of the bulb remains. The casing is formed from two 44A and 44B of lightly sintered highly reflective alumina (Al ₂ O ₃ ), as shown. The particle size distribution and crystal structure of the casing material must be able to provide the desired optical properties. Powdered bauxite is sold by various manufacturers, for example, bauxite sold by Nichia America Corp. under the designation NP999-42 is suitable. The accompanying drawing is a cross-sectional view (taken through the center of the bulb) of the bulb, sleeve and aperture. The tip-off header is not shown in the figure. The ID (inner diameter) of the casing is spherical except for the area near the enclosure (not shown). The partially sintered casing is sintered to such an extent that necking (connections between particles) of the particles can be observed on a microscale. Sintering is governed by the desired thermal conductivity through the ceramic. The purpose of the constriction is to enhance heat transfer with minimal impact on the reflectivity of the ceramic. The ceramic halves fit very tightly and can be held together by mechanical means, and alternatively can be glued together using, for example, General Electric Arc Tube Coating No. 113-7-38. The housing ID and bulb OD are chosen such that the average air gap allows sufficient heat conduction away from the bulb, and the thickness of the ceramic is chosen for the desired reflectivity. The bulb works with an air gap of a few thousandths of an inch and a minimum ceramic thickness of only 1mm.

In another embodiment described above, the material used for the bulb is quartz ( _SIO2 ) and the reflective coating is silica ( _SiO2 ). Since the materials are the same, there is no problem of different thermal expansion. Silica is amorphous and consists of small plates that are slightly fused together. It is made thick enough to achieve the required reflectivity and is white. Silica can also be applied in the form of an unattached casing.

When using the mentioned fillings based on sulphur, selenium and tellurium, they have the advantage of being independent of the filling, although the device aspects of the invention described above (and in conjunction with Figures 6 to 13) are particularly adaptable, thus It can be advantageously used with any fill, including various metal halide fills such as tin halides, indium halides, gallium halides, bromine halides (eg, iodide), and thallium halides.

When sulfur and selenium based fillers are used together, the material of the jacket 44 in FIG. good. The coating reflects substantially all ultraviolet and visible radiation impinging on it, at least in the range (UV and visible) between 330nm and 730nm, which means that the reflectivity of the casing in the ultraviolet and visible part of the spectrum is greater than 85% . Such a reflectivity is preferably greater than 97%, more preferably greater than 99%. Reflectivity is defined as the total fraction of incident radiant power returning to the interior in the above wavelength range, for which one requires high reflectivity because any loss of light is multiplied by the number of reflections. Enclosure 10 is preferably a diffuse reflector of radiation, but may also be a specular reflector. The casing reflects incident radiation regardless of the angle of incidence. The above-mentioned reflectance percentages preferably extend to wavelengths well below 330nm, for example, down to 250nm, preferably down to 220nm.

Although not required, it is also advantageous for the casing to be reflective in the infrared region, so preferred materials are highly reflective from far ultraviolet to infrared. High infrared reflectivity is desired because it improves energy balance and allows lower power operation. The envelope must also be able to withstand the high temperatures generated in the bulb. As mentioned above, alumina and silica are suitable materials and come in the form of casings that are sufficiently thick to provide the required reflectivity and structural rigidity.

As noted above, in work with sulfur or selenium bulbs, the multiple reflections of radiation by the envelope simulate the effect of a much larger bulb, allowing for lower densities of active material and/or smaller bulbs Work. Each absorption and re-emission of a collection of photons (including those corresponding to the reflected substantially ultraviolet radiation) results in a shift in spectral power to be distributed toward longer wavelengths. The greater the average number of photons reflected in the bulb bulb, the greater the number of absorption/re-radiation and thus the resulting spectral shift associated with the photons. The spectral shift will be determined by the vibrational temperature of the activated species.

Although the aperture 48 is depicted as not being covered by the casing in Fig. 3, it is preferably provided with a substance which has a high UV reflectivity but is highly transparent to visible radiation. An example of such a substance is a multilayer dielectric stack that has the desired optical properties.

The parameter α is defined as the ratio of the surface area of the aperture to the total area of the reflective surface (including the area of the aperture). α can then take values around zero (for very small holes) to 0.5 (for half enveloped bulbs). A preferred α has a value in the range of 0.02 to 0.3 for many applications. Depending on the particular application, ratios outside this range may work, but may not be as effective. Typically, smaller alpha values generally increase brightness, decrease envelope temperature, and decrease efficacy. It is therefore an advantage of the present invention that an extremely bright light source can be provided.

Another embodiment is shown in FIG. 6 which utilizes an optical port in the form of an optical fiber 14 which interfaces with the aperture 12 . The area of the small hole is considered to be the cross-sectional area of the port. In the exemplary embodiment of FIG. 6 the diffusely reflective envelope 10 surrounds the bulb 19 .

Another embodiment is shown in Fig. 7, in which parts similar to those in Fig. 6 are indicated by like reference numerals. Referring to FIG. 7, the port of light connected to the aperture 12' is a compound parabolic reflector (CPC) 70. As is known, the CPC cross-section presents two parabolic portions inclined to each other at an inclination angle. It is efficient to convert light that has an angular distribution from 0 to 90 degrees to a much smaller angular distribution such as 0 to 10 degrees or less (maximum 10 degrees from normal). The CPC can be a reflector working in air or a refractor using total internal reflection.

In the embodiment shown in FIG. 7, the CPC can be arranged, for example, by covering the inner surface of the reflective CPC so as to reflect UV and visible light, while providing an end face 72 which passes visible light, but which end face 72 can be constructed or covered so that it will not want to The desired radiation component is reflected back to the aperture. These unwanted components may include, for example but are not limited to, particular wavelength regions, particular polarizations, and spatial orientations of light rays. Surface 72 is shown as a dashed line, meaning that it both passes and reflects radiation.

Figure 8 is another embodiment utilizing CPC. In this embodiment, the bulb is the same as in Figure 7, but the light port is an optical fiber 14", which feeds the CPC 70. In the embodiment of Figure 8, less heat reaches the CPC than in the embodiment of Figure 7 .

The problem in the embodiments of Figures 6 to 8 is that there is an intersection between the bulb and the light port where light leaks out.

Referring to Fig. 3, this problem can be solved by using the inner diffuse reflective wall 47 of the casing forming hole in front of the aperture as the light port. Thus, referring to Fig. 9, the optical fiber 80 is placed in front of the diffusing aperture, while in Fig. 10, a solid or reflective optical element 82 (eg, a CPC) is placed in front of the aperture. Light diffuses through the aperture and enters the fiber or other optical element smoothly without encountering any abrupt intersections. Depending on the application, the diameter of the optical element can be larger, smaller or the same diameter as the aperture.

Make the diffuse hole long enough to randomize the light, but not so long that too much light is absorbed. Figures 11 to 13 show various hole designs. In Fig. 11, the casing 92 has a bore 92 in which a flat front surface is presented. In Figure 12, the casing 91 has a hole 93 which extends beyond the thickness of the casing. In FIG. 13 , casing 95 has aperture 97 and zone 98 of graduated thickness. Typically the cross-sectional shape of the holes is circular, but could be rectangular or some other shape. The internal reflective walls can be converging or diverging, the design of these holes is exemplary and other designs will be apparent to those skilled in the art.

Referring to Figures 3, 9, 10 and 11, reflector 49 (96 in Figure 11) is shown. The reflector is placed in or close to contact with the casing 44 and its function is to reflect light that escapes at or near the interface near the aperture. While reflectors are optional, one would like to improve their performance. Light reflected back into the ceramic near the interface will primarily return to the pinhole or bulb (unless lost due to absorption). The radial dimension of the reflector 49 (in case the hole has a circular cross section, the reflector will be toroidal and the dimension will be "radial") should be about the same as the height of the hole 47 or smaller. In the visible it is preferably quartz with a covering dielectric stack.

FIG. 14 depicts an embodiment of the invention in which a UV/visible reflective coating 51 is located on the wall of a metal housing 52 . In the housing is the bulb 50 without the reflective covering. A mesh 54 (which is also an aperture) completes the enclosure. The reflective surface forces light to exit through the mesh area. The housing may be a microwave resonator, and microwave excitation may be introduced through, for example, coupling slots in the cavity. In an alternative, microwave or R.F. power can be applied inductively, in which case the enclosure need not be a resonant cavity, but can provide effective shielding.

One embodiment that provides effective shielding is shown in FIG. 15 . The bulb is similar to that in the embodiment described with reference to FIG. 3 , although in this particular embodiment it has a larger alpha than shown in FIG. 3 . It is powered by microwave or R.F. power, which excites a coupling coil 62 (shown in cross-section) around the bulb. (Except for the area around the optical port 69) a Faraday shield 60 surrounds the device for electromagnetic shielding. Lossy ferrite or other magnetic shielding material may be provided on the outside of housing 60 to provide additional shielding, if desired. In other embodiments, other optical elements may communicate with the aperture, in which case the Faraday shield will contain the device except for the area surrounding the optical element. The opening of the closed box is small enough that it exceeds the cutoff. The density of the active substance in the filling can vary from the same value as the standard value to very low density values.

While the present invention is capable of producing stable visible light without the need for rotating the bulb, in some applications, bulb rotation may be desired. The embodiment of Figure 16 describes how this need can be achieved. Referring to the accompanying drawings, rotation is performed by an air turbine so as not to block visible light. The air bearing 7 and the air inlet 8 are shown in the figure, and the air from the air turbine (not shown in the figure) is sent to the air inlet.

Although implementation of the method aspects of the invention has been described in connection with reflective media on the bulb or an internal shielding enclosure, it is not so limited that only reflective media need be provided so as to reflect radiation through the filling multiple times. For example, a dielectric reflector can be placed on the outside of the bulb. Also, in embodiments using microwave cavities with coupling slots, loss of light can be avoided by covering the slots with a dielectric reflective cover.

The principle of the wavelength conversion described above is described below with reference to Fig. 17, which depicts the spectra in the ultraviolet and visible regions of bulbs of respective electrodeless lamps comprising a sulfur filling. Spectrum A was taken from a bulb with a low sulfur fill density (approximately 0.43 mg/cc) and without any reflective envelope or covering. It can be seen that a part of the radiation emitted by the bulb is in the ultraviolet region (defined here below 370 nm).

Spectrum B, on the other hand, was taken from the same bulb with a covering to provide multiple reflections according to an aspect of the invention. It can be seen that there is a greater proportion of radiation in the visible region of the spectrum B, while the radiation in ultraviolet light is reduced (over) by at least 50%.

While Spectrum B depicted in FIG. 17 is suitable for some applications, a spectrum with a greater proportion of visible light and a lesser proportion of ultraviolet light can be obtained by using an overlay with higher reflectivity. As mentioned above, the smaller the aperture, the more relative visible light is produced, but the less efficiently. An advantage of the present invention is that by making the aperture very small, a bright light source can be obtained, such as is useful in some projection applications. In this case, higher brightness is obtained with lower efficiency.

In the lamp used to obtain Spectrum B, a spherical bulb made of quartz (ID 33 mm, OD 35 mm) was filled with sulfur at a density of 0.43 mg/cc and argon at 50 toor. The bulbs used in Figures 17 to 20 are used only to demonstrate the method of the present invention and are covered. As noted above, bulbs using overlays are not used in a commercial implementation because of longevity concerns. The bulbs in Figures 17 and 18 were covered with alumina (G.E. Lighting Product No. 113-7-38) (except for the pinhole area) with a thickness of 0.18 mm and an alpha of 0.02. The bulb was surrounded by a cylindrical microwave cavity with a coupling slot and an applied microwave power of 400 watts was applied, which resulted in a power density of 21 watts/cc.

The spectra in Fig. 17 have been normalized, ie the peaks of the respective spectra have been arbitrarily equalized. The lamps of Figures 17 and 18 operate without rotating the bulb. The unnormalized spectra are shown in Figure 18.

Figure 19 depicts the normalized spectrum A of an R.F. powered sulfur lamp without a covering, which has a significant spectral component in the ultraviolet region, and the spectrum B obtained from the same lamp with a reflective covering. It can be seen that the proportion of visible light radiation is larger in spectrum B. In this case, the bulb is ID 23mm with an OD of 25mm and a sulfur filling density of 0.1 mg/cc of sulfur and 100 toor of krypton. Power is supplied at 220 watts for a power density of 35 watts/cc. Covering The light bulb is covered with alumina to a thickness of about 0.4 mm and an alpha of 0.07. Without rotating the bulb, the operation of the lamp is stable and the non-normalized spectrum is shown in FIG. 20 . Although the radiation is lost in multiple reflections, the non-normalized spectrum B appears higher than the spectrum A because the detector used is illuminated by only a part of the radiation emitted from the uncovered bulb, but by the A larger portion of the radiation emitted by the small hole is directed towards the .

Comparing Figure 18 and Figure 20, it can be noticed that larger α leads to higher performance. Referring to Figure 18, note that the output of visible light in a covered bulb is lower than that in an uncovered bulb because radiation is lost in multiple reflections; however, the output of visible light is lower than if The output is greater for reflection without conversion from UV to visible light.

According to the present invention, in some embodiments, the bulb can be filled with a much lower density active material than in the prior art.

The present invention can be used with bulbs of different shapes, such as spherical, cylindrical, oblate spheroidal, annular, etc. Uses of the lamp according to the invention include use as a projection light source and as an illumination light source for general lighting.

It should be noted that bulbs of different wattages can be provided, from lower wattages (eg, 50 watts) to over 300 watts (including 1000 watts and 3000 watts). Since the light can be taken out through the light port, the loss of light can be low, and the light taken out through the port can be used for distributed lighting (for example, in an office building).

According to another aspect of the invention, the bulbs and lamps described herein can be used as a recapture engine for converting ultraviolet radiation from any source to visible light. For example, an external ultraviolet lamp may be provided and light emitted from the lamp sent, through the light port, into the bulb as described herein. The bulb then converts the ultraviolet emission to visible light.

Finally, it should be understood that although the invention has been described in conjunction with illustrative embodiments, various changes will occur to those skilled in the art, and the scope of the invention is therefore determined by the appended claims.

Claims (50)

1. the method that radiation is provided is characterized in that comprising the steps:

The lamp filler is provided, and it comprises at least a material of selecting from the group of sulphur and selenium when excitation,

Encourage described lamp filler, so that described sulphur or selenium produce molecular radiation, described molecular radiation comprises sizable spectral power component and comprises the spectral power component in the visible region at spectrum in the ultraviolet range of spectrum,

In the space that comprises, pass the radiation that described filler repeatedly reflects described generation, because described sizable spectral power component is arranged in the ultraviolet range, the path that passes described filler is converted at least a portion radiation the radiation in the visible region effectively, cause radiation through conversion, described radiation constituting by ultraviolet radiation that reduces and visible radiation through conversion, this visible radiation such as fruit under the situation that does not have described conversion in from the ultraviolet range to the visible region, the visible radiation that the generation reflex time will have is bigger, and

From the described visible light of the described spatial emission that comprises.

2. the method for claim 1 it is characterized in that the described sizable spectral power component in the ultraviolet range of described spectrum has first value, and the described ultraviolet radiation that reduces is littler by 50% than described first value at least.

3. method as claimed in claim 2, it is characterized in that having sizable spectral power component described in the ultraviolet range of described spectrum of described first value and be the radiation that in ultraviolet ray and visible region, produces the spectral power component summation at least 20%.

4. method as claimed in claim 2, it is characterized in that the described spectral power component in the visible region of spectrum has second value, and increase at least 50% of difference between the value of spectral power component of described first value and the described ultraviolet radiation that reduces from the described visible radiation that the described spatial emission that comprises is come out by described second value.

5. the method that radiation is provided is characterized in that comprising the steps:

The lamp filler is provided, and it comprises at least a material of selecting from the group of sulphur and selenium when excitation,

Encourage described lamp filler, so that described sulphur or selenium produce molecular radiation, described molecular radiation is included in spectral power component in the ultraviolet range of the spectrum with given value level and the spectral power component in the visible region of spectrum,

In the space that comprises, pass the radiation that described filler repeatedly reflects described generation, since the ultraviolet range have described in the spectral power component, the path that passes described filler is converted at least a portion radiation the radiation in the visible region effectively, cause radiation through conversion, described radiation through conversion is by having than described given ultraviolet radiation that reduces of value little at least 50% and constituting of visible radiation, this visible radiation is bigger such as the visible radiation that fruit will have when not having described conversion in from the ultraviolet range to the visible region, and

From the described visible light of the described spatial emission that comprises.

6. method as claimed in claim 5, it is characterized in that the described spectral power component in the visible region of spectrum has a certain value, and the described visible radiation of coming out from the described spatial emission that comprises is increased at least 50% of difference between the value of spectral power component of described given value and the described ultraviolet radiation that reduces by described a certain value.

7. as claim 1 or 5 described methods, it is characterized in that described at least a material is a sulphur.

8. method as claimed in claim 7 is characterized in that the described of conversion from described sulphur mainly is visible radiation through radiation.

9. as claim 1 or 5 described methods, it is characterized in that described at least a material is a selenium.

10. method as claimed in claim 9 is characterized in that the described radiation through conversion from described selenium mainly is a visible radiation.

11., it is characterized in that described at least a material is sulphur and selenium as claim 1 or 5 described methods.

12., it is characterized in that the described radiation through conversion from described sulphur and selenium mainly is a visible radiation as 11 described methods of claim.

13., it is characterized in that the step of described reflection comprises reflection all described radiation in described spectrum ultraviolet range haply as claim 1 or 5 described methods.

14. as claim 1 or 5 described methods, the step that it is characterized in that described reflection comprises the described radiation more than 97% in the ultraviolet range of reflecting described spectrum.

15. as claim 1 or 5 described methods, it is characterized in that the described space that comprises comprises glass bubble, described glass bubble comprises described lamp filler.

16. as claim 1 or 5 described methods, it is characterized in that the described space that comprises comprises excitation cavity, in described excitation cavity, placed the glass bubble that comprises described lamp filler.

17. a light-emitting device is characterized in that comprising:

Electrodeless glass bubble comprises formation discharge filler, and described glass bubble has first and second parts, and

Be used to approach the diffuse reflection silicate lining layer of described first glass bubble part, it contacts a position of described glass bubble at least, and can not break under working temperature owing to the different thermal expansion between described glass bubble and the described cover layer,

The second portion of wherein said glass bubble comprises loophole, and described diffuse reflection silicate lining layer is by described loophole reverberation.

18. device as claimed in claim 17 is characterized in that described diffuse reflection silicate lining layer comprises the sheath body that is not adhered to described glass bubble.

19. device as claimed in claim 18 is characterized in that described sheath body contacts a plurality of positions of described glass bubble.

20. device as claimed in claim 19, those parts that it is characterized in that the described glass of not contacting of described sheath body bubble are steeped with described glass and are separated by in the some thousandths of inch.

21. device as claimed in claim 17 is characterized in that described diffuse reflection silicate lining layer is used and the material identical materials of described glass bubble is made.

22. device as claimed in claim 21 is characterized in that described material is a tripoli.

23. a light-emitting device is characterized in that comprising:

Electrodeless glass bubble comprises formation discharge filler, and this glass bubble has first and second parts,

The reflection sheath body that diffuses around the described first of described glass bubble, the described reflection sheath body that is not attached to described glass bubble contacts with it in a position of described glass bubble at least, and

The described second portion of described glass bubble comprises loophole, and described sheath body is by described loophole reverberation.

24. device as claimed in claim 23 is characterized in that described glass bubble is made of described first and second parts.

25., it is characterized in that also comprising the optical port that extends from described aperture as claim 23 or 24 described devices.

26. device as claimed in claim 25 is characterized in that described sheath body contacts described glass bubble in a plurality of positions.

27. device as claimed in claim 23 is characterized in that those parts of the described glass bubble of not contacting of described sheath body and described glass bubble separate the some thousandths of inch.

28. device as claimed in claim 25 is characterized in that described sheath body is the powder that sintering is crossed.

29. device as claimed in claim 25 it is characterized in that described glass bubble is spherical, and described sheath body is formed by semicircular two parts.

30. device as claimed in claim 25 is characterized in that described sheath body comprises the light diffusion hole, described hole comprises described optical port.

31. device as claimed in claim 30 is characterized in that described hole long enough, so that enter the light randomization in described hole.

32. device as claimed in claim 31 is characterized in that described optical port comprises fiber optic component.

33. device as claimed in claim 31 is characterized in that described optical port comprises compound parabolic concentrator.

34. device as claimed in claim 25 comprises sulphur, selenium or tellurium when it is characterized in that described filler excited target, is used for mainly providing visible radiation.

35. device as claimed in claim 25 is characterized in that described sheath body makes with such material, and enough thick, thereby all visible lights incident thereon and ultraviolet radiation are reflected haply.

36. device as claimed in claim 25 is characterized in that and be used to providing the microwave or the R.F. generation device of electromagnetic power, and and to be used for described electromagnetic power is coupled to the device of filler of described glass bubble combined.

37. a light-emitting device is characterized in that comprising:

Involved filler, it comprises at least a material of selecting from the group of sulphur and selenium when excitation, and

Surround described filler, the shell that constitutes by first and second parts, in the described first of described shell or reflector on every side, it passes by reflecting all haply that filler incides ultraviolet ray on it and the material of visible radiation is made, the described second portion of wherein said shell comprises the small-bore, described aperture is not centered on by described reflector, and is transparent haply to visible light.

38. device as claimed in claim 37, it is characterized in that described material is occurring in the filler of excitation with predetermined quantity, and what described predetermined quantity and the combination of passing the described reflection of described filler were enough to produce in the visible light part of described spectrum mainly is molecular radiation institute spectrum, and this visible light part emits from described aperture.

39., it is characterized in that described material is a diffuse-reflective material as claim 37 or 38 described devices.

40. device as claimed in claim 39, it is characterized in that described diffuse-reflective material reflection incident thereon greater than 97% ultraviolet ray and visible radiation.

41. device as claimed in claim 40, it is characterized in that described diffuse-reflective material reflection incident thereon greater than 99% ultraviolet ray and visible radiation.

42. device as claimed in claim 39 is characterized in that the uv reflectance radiation haply of described aperture.

43. device as claimed in claim 41 is characterized in that described diffuse-reflective material comprises alum clay.

44. device as claimed in claim 39 is characterized in that described device is the bulb of electrodeless lamp, and described shell is the glass bubble that comprises described filler.

45. light-emitting device as claimed in claim 44, it is characterized in that described reflector comprises sheath body, described sheath body centers on the described first surface part of described glass bubble, and contacts the described first surface part of described glass bubble at least one position, but is not adhered to this place.

46. light-emitting device as claimed in claim 37 it is characterized in that described shell around described glass bubble, and be metal, and described reflector is on the inboard of described metal shell.

47. an electrodeless lamp is characterized in that comprising:

Comprise the glass bubble that forms the discharge filler,

The first of described glass bubble has light reflecting material,

The second portion of described glass bubble comprises an aperture,

Optical port with described aperture is aimed at reaches

Metal shell around described glass bubble, it seals except that the opening that described optical port extends, in described shell, approach the inductive couplings device of described glass bubble, and R.F. generation device, be used to encourage described inductive couplings device, it is with the filler in the described glass bubble of the described R.F. power degree of coupling.

48. an electrodeless lamp is characterized in that comprising:

Comprise the electrodeless glass bubble that forms the discharge filler, have first and second parts,

Around the shell of described first, and

Stay the diffuse reflective powder between described shell and the described glass bubble,

Wherein, the described second portion of described glass bubble comprises printing opacity and penetrates aperture, and described powder is by described aperture reverberation.

49. lamp as claimed in claim 48 is characterized in that described shell also made by diffuse-reflective material.

50. device as claimed in claim 30 is characterized in that also comprising the reflection unit that is adjacent to described hole, is used for light reflected back hole at the interface, hole.

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