MXPA97008082A - Compact microon lamp - Google Patents

Abstract

A micro wave lamp having a compact structure and using a localized coupling notch displaced from the center in one direction and an inclined bulb stem which is located displaced from the center in the opposite direction. An unconventional waveguide is used that is approximately the width of a VR-284 waveguide, and approximately the length of a VR-3 waveguide.

Description

COMPACT MICROWAVE LAMP DESCRIPTION OF THE INVENTION The present invention relates to a lamp that receives the microwave power and particularly to a lamp of that type having a compact structure. Recently, micro wave power lamps using sulfur or selenium-based fillers to efficiently radiate in the visible region have been filed, for example, U.S. Patent No. 5,404,076, issued April 4, 1995, which is incorporated herein by reference. reference. Such micro wave lamps can be used as lighting sources, and find a particular use in commercial or industrial lighting. For such lighting applications, it is desirable to construct a lamp system that fits within the general test of some of the lamps already in existence. Many of these are equipped with quite large inductive resistors, which are installed in superior places attached to the associated lamp. Therefore, a new lamp system would be more useful if it occupied a package of comparable size that could be similarly placed. This requires that the different parts of the lamp system without electrodes be kept as small as reasonably possible. These parts include a quartz bulb to contain the arc plasma placed inside a micro wave cavity that has a metal mesh to hold the micro waves, but allows the escape of light, a magnetron to produce the micro waves, a guide of waves to carry the magnetron micro waves to the cavity, an energy supplement to drive the magnetron and cooling fans or other means to cool the magnetron and its energy supply. The lamp bulb is rotated within the micro wave cavity to stabilize the discharge, thereby adding a motor to the system. To increase the versatility of the new lamp and therefore the number of places in which it can be used, the lamp itself does not include a reflector. Rather the lamp has to be inserted through a hole in reflectors of different designs suitable for use in applications that require the dispersion of light in different areas. This requires that the light source extends outward from the lamp housing a distance of at least 100mm, keeping the inlet hole with a small diameter, increases the efficiency of the reflector. It is desirable to keep the total length of the lamp as small as possible. Since the motor that rotates the bulb must be placed outside the micro wave fields, this potentially increases the length of the lamp system. In such a configuration, the stem of the bulb is fed through the coupling notch and the waveguide, and the motor and coupler are located on the other side of the waveguide, which results in a very strong trunk stem. long easy to break. Another problem is that the waveguide must have a sufficiently narrow width, so that the cut-off frequency is high enough to eliminate spurious interference signals, which could be generated but must have a sufficient height to prevent arcs from forming. the place of the magnetron antenna. A conventional waveguide WR-284 is narrow enough to eliminate interference signals, but due to its height that is related to its width in a conventional ratio of approximately 1 to 2, arcs are presented. Thus, it is an object of the present invention to provide an illumination lamp with microwave power having a compact structure. It is another object to provide a lighting lamp with micro wave power where the rod that supports the bulb is not very long.

It is another object of the invention to provide a lamp where arc formation is avoided.

According to a first aspect of the invention, a micro wave lamp is provided, wherein the coupling notch is located in the end wall of the cavity on one side of the center, while the rod of the bulb passes through the end plate on the other side of the center and it has a different angle of 90 degrees, in relation to the end wall, so that the bulb is supported centrally in relation to the structure of the wall of the cavity. A motor and a shaft coupling to the stem of the bulb are located at the end of the rod outside the cavity. In this way, the stem of the bulb that is provided is not particularly long, and therefore provides a more robust and durable support structure. According to another aspect, the waveguide feeding the coupling notch is oriented in such a way that its length is parallel to the end wall of the cavity, thus bringing the total length of the lamp to a minimum. According to yet another aspect of the invention, a novel waveguide structure is used in which the waveguide is approximately the height of a waveguide WR-340 although it has the width of a waveguide WR-284. In this way the height of the magnetron antenna is accommodated without arc, while spurious signals that could cause interference are eliminated.

The invention will be better understood by referring to the accompanying drawings, wherein: FIGURE 1 is a side view of a lamp according to an embodiment of the invention; FIGURE 2 is a top view of the waveguide portion of the lamp presented in Figure 1; FIGURE 3 is a sectional view of the waveguide of the lamp of Figure 1, taken perpendicular to the coupling notch; FIGURE 4 is a plan view showing how the magnetron and associated components are mounted on the lamp of Figure 1. Referring to Figure 1, a lamp according to one embodiment of the invention is shown. The lamp is composed of bulb 2 that is located in a microwave cavity. The bulb may be made of quartz and includes a discharge forming means, for example, a sulfur or selenium-based filler. The microwell cavity is cylindrical, and comprises a sidewall structure, and two end walls. The side wall and the upper end wall in the orientation of Figure 1, are made of a cylindrical metal mesh, shown in part with the figure 3, which allows the light to come out but is basically opaque to the microwave radiation. The lower end wall of the cavity in the orientation of Figure 1 is the outer surface 8 of the waveguide 10. As mentioned above, the microwave light shown in Figure 1 can be used to replace existing lamps that are not microwaves and therefore it is desirable that the lamp be made as compact as possible to fit within the general test of existing lamps. In some prior art microwave lamps where the rod of the bulb extends from an end wall, it passes through the waveguide that feeds the cavity, and the motor and the coupling ferrule are mounted on the side opposite of the waveguide, enough has been left to have no microwave fields. Such an arrangement, however, may have the effect of increasing the length of the lamp, as well as the length of the bulb of the bulb, making it sensitive to breakage. In accordance with the present invention, the coupling notch is located on one side of the center in the end wall of the cavity, while the rod of the bulb is fed through the end wall to the other side of the center inclined in relation to the wall. extreme, with the motor and the splint being mounted outside the cavity and away from the waveguide. Additionally, the long direction of the waveguide extends parallel to the end wall of the cavity, so as not to extend over the length of the lamp. The result is a more compact lamp with a shorter total length, where the bulb is more solidly supported on a shorter stem. Referring again to Fig. 1, the rectangular waveguide 10, which has the inner wall 12, and the outer 8, the upper walls of the waveguide have the groove or coupling notch 14, which is shown in FIG. shown in Fig. 2. As also the outer wall 16 is shown, the waveguide extends just beyond the coupling notch. The magnetron 18, which has the antenna 20, is mounted to the waveguide as shown, the micro wave power is fed to the waveguide and through the coupling notch 14, into the micro wave cavity where it exists the filling in the bulb 2. FIG. 2 shows the hole 21, through which the magnetron antenna and a lining penetrate. Referring to FIGS. 1, 2, the bulb rod 22 has, through the hole 24, a different angle of 90 degrees (approximately 77 degrees in the preferred embodiment), so that the bulb is located centrally in relation to the structure of the mesh side wall of the cavity. The motor 26 is mounted to the support of the motor 28, while the splint 30 couples the motor shaft to the stem of the bulb., which is typically made of quartz. The extension 34, of the support 28, is fixed to the lower outer surface of the waveguide, insofar as there is a lumen 36, between the motor support and the end wall of the waveguide. In Fig. 1, the upper wall 8 of the waveguide extends to the left at the reference number 40, after the end of the waveguide. Additionally, the upper part of the waveguide is flush against the plate 32, which is fixed to the plate 42, at the ends thereof with the flanges 44, 46. Referring to Figs. 1 and 2, the metal ring 52 is mounted on the upper surface of the waveguide (end of the cavity). The cylindrical mesh is fixed to this ring by a clamp and the mesh passes through a hole in the plate 42. A transparent cylindrical envelope 54, which may be made of glass or quartz, surrounds the screen and is mounted on the plate 42, for example, by the retainer 56, which provides thermal insulation in the space between the plates 32 and 42. During the operation of the lamp micro wave power generated by the magnetron is fed through the wave line and the notch coupling to the cavity in which the bulb 2 is located. In order to make the device as compact as possible and provide a stable relationship between the magnetron and cavity, the antenna of the asnetron 2, is located 1/4, of the guide wavelength (the wavelength of the signals propagating within the waveguide), from the coupling notch 14. Additionally, it was found that a waveguide having a sufficient width It was necessary to have a sufficiently high frequency cut to eliminate spurious signals. For example, a waveguide was tested that accommodated the magnetron antenna producing 200Mhz band signals, below the normal operating point of 2.450Mhz, and the use of the waveguide length of 1/4, of the wavelength to which we have referred, would aggravate this situation. It was found that a WR-284 waveguide, (equivalent to the IEC designation, R-32), was narrow enough to eliminate spurious signals, but it was found that the height of this waveguide was too small to accommodate the antenna. agnetron without arch. To solve this problem an unconventional waveguide was used, which had approximately the width of the waveguide WR-284, of approximately the height of the WR-340 guide, (equivalent designation IEC, R-26), this blocks the transmission of signals below 2.078 Mhz, and helps to suppress the low frequency output of the band signals by reducing the phase change between magnetron and the coupling notch. At the same time, the height of the waveguide is sufficient to accommodate the magnetron antenna without arc. The extreme waveguide wall behind the magnetron moves further away than is the usual practice. In the prototype test a metallic tuning button was used to couple the impedance of the lamp to the waveguide; this button worked like a capacitor instead. With the reduction in length to 1/4 of the wavelength, this position became the same as the magnetron's antenna, a tuning button could have been placed on one side of the antenna, taking care to avoid the arc, however , the magnetron antenna itself is a capacitor through the waveguide, this is usually compensated by placing the end wall in an inductive position closer to the antenna, than 1/4 wavelength. By moving the wall further out, the object is reduced, and the antenna is viewed as the desired tuning capacitance. The best position was found experimentally using an extreme movable wall of the waveguide. In many previous microwave lamps, the coupling is done by placing a tuning button on the waveguide, if all possible charging phases have to be corrected, a half wavelength of the waveguide is needed. Instead, the system was coupled by placing a thin block 60, shown in Fig. 2, on one side of the recess to modify the current path. Referring to Fig. 3, it is a back view of the back of the lamp in Fig. 1, (inverted from left to right), the dielectric member 62 is presented, which may be made of mica. This member rests against the inner end wall of the waveguide, and extends or protrudes through the coupling recess 14, as it rests against the recess edge. Basically, it can be as wide as the notch; The purpose of member 62 is to prevent the arch through the recess. Fig. 4 is a plan view of the magnetron and associated components that are located on the plate 32, shown in Fig. 1. The magnetron 18 receives filament power from the filament transformer 70, while the decreasing transformer 72, can be used to provide power to the motor 26, which rotates the bulb, which is shown in connection with the motor assembly 28, and the capacitor 74. In Fig. 4, the magnetron cooling air fan 76 , it is presented as it is in the control table PC-78; finally the waveguide 10 is shown feeding the coupling notch 14.

Although the invention has been described in relation to a preferred embodiment, many obvious variations can be presented to the technicians, without departing from the spirit and scope of the present invention.

Claims (10)

1. R E I V I N D I CA C I ON E S 1.- A lamp without electrodes comprising: a micro wave cavity having an end wall and a side wall structure; a bulb that contains a filling that forms the discharge and that is arranged in that cavity; means for generating the power of microwaves; means for coupling the microwave power to the cavity; means for coupling include a recess in the end wall of the cavity, recess that is located to one side of the center of the end wall along a given choice, and a waveguide extending in a longitudinal direction that is approximately parallel to the extreme wall; a rod to support the bulb, which rod passes through a hole in the end wall which is located on the other side of the center of the end wall in the given direction, the rod is oriented at a different angle of 90 degrees, with respect to to the said end wall to place the bulb in a central position in reference to the side wall structure of the cavity; and means for the motor located outside the cavity with an axis that is coupled to the stem outside the cavity to rotate said stem.
2. 2. Lamps without electrodes according to claim 1, characterized in that the majority of the length of the waveguide is arranged on the side of the coupling notch remote from the bulb.
3. 3. Lamp without electrodes according to claim 2, characterized in that the micro wave cavity is a cylindrical cavity TE, ^.
4. 4. Lamp without electrodes according to claim 3, characterized in that the cavity is made of metal mesh with the exception of the end wall and where there is a transparent envelope surrounding the mesh.
5. 5. Lamp without electrodes according to claim 4, characterized in that there is a metal tuning member fixed adjacent the recess.
6. 6. Lamp without electrodes according to claim 4, characterized in that there is a dielectric member to prevent the arch against a wall of the recess.
7. 7. Lamp without electrodes according to claim 2, characterized in that the means for generating power of microwaves is a magnetron having an antenna and the dimension of the waveguide between the antenna and the recess is about 1/4 of the wavelength of the guide.
8. 8. Lamp without electrodes according to claim 2, characterized in that the means for generating microwave power is a magnetron having an antenna, which nominally provides a microwave power of 2,400 MHz, the antenna extends within the waveguide perpendicular to the length direction thereof and parallel to the height dimension of the waveguide, wherein the waveguide has a height dimension that is approximately the height of a waveguide WR-340 , and wherein the waveguide has a width dimension that is approximately the width of a waveguide WR-284.
9. 9. Lamp without electrodes according to claim 8, characterized in that the dimension of the waveguide between the antenna and the recess is approximately 1/4 of the wavelength of the guide.
10. 10. A lamp without electrodes comprising: a micro wave cavity; a bulb containing a filling that forms the discharge arranged in the cavity; a magnetron to generate a nominally 2.450 MHz micro wave power with the magnetron having an antenna; means for coupling the micro wave power to the cavity and means for coupling including a recess in the cavity and a waveguide, the magnetron feeds the waveguide so that the antenna is parallel to the height dimension of the same; The waveguide has a height dimension that is approximately of a VR-340 waveguide, and has a width dimension of approximately the width of a WR-284 waveguide. R E S UM E N A microwave light that has a compact structure and uses a localized coupling notch displaced from the center in one direction and an inclined bulb rod that is located offset from the center in the opposite direction. An unconventional waveguide is used which is approximately the width of a VR-284 waveguide, and approximately the length of a VR-340 waveguide.