JP2625125B2 - High resolution electrodeless light source device - Google Patents

Description

Description: TECHNICAL FIELD The present invention generally relates to an electrodeless light source device, and more particularly, to a microwave-excited electrodeless light source device and various types thereof suitable for use therein. It relates to related devices.

2. Description of the Related Art A microwave-excited electrodeless light source device is conventionally known.
In such an apparatus, a lamp or sphere containing a gas and a solid and / or liquid additive element is located in a microwave chamber or cavity. The microwave cavity is typically defined by a solid wall portion and a mesh wall portion that transmits light but reflects microwaves. Microwaves are introduced into the microwave cavity through coupling slots formed in the solid wall portion, so that the lamp absorbs the introduced microwaves and emits light. In such a microwave light source device, no electrodes are provided for the lamp, and therefore, the lamp has a relatively longer life than a conventional lamp having electrodes. Therefore,
The microwave light source device can provide a stable light output for a longer period of time as compared with a conventional lamp having electrodes.

However, in microwave light sources, there have been difficulties in providing high intensity light output because the lamp must be excited by microwaves, usually generated by a magnetron. This is due in part to the fact that commercially available magnetrons have a fixed rating, they are not versatile and have rather limited power. Therefore, in order to obtain high intensity light output, a magnetron with special performance must be ordered, which can be very costly. Further, the microwave light source device is expected to be applied in the fields of printing and semiconductor manufacturing. In such a case, higher resolution is required, and good uniformity is required over a relatively large area in order to apply the microwave light source device in these technical fields. Therefore, there is a need to develop an improved microwave-excited electrodeless light source device that can satisfy these newly generated requirements.

Object The present invention has been made in view of the above points, and has as its main object to provide an electrodeless light source device which solves the above-mentioned disadvantages of the prior art and improves it. It is another object of the present invention to provide a microwave-driven electrodeless light source device capable of supplying a stable and high-intensity light output for a long period of time. It is still another object of the present invention to provide a microwave driven electrodeless light source device having high resolution and high image quality. It is still another object of the present invention to provide a microwave driven electrodeless light source device capable of providing a good uniform light output over a wide area.

According to one aspect of the present invention, there is provided a microwave drive comprising: a microwave cavity extending along a longitudinal axis; and a means disposed in the cavity for absorbing microwaves and emitting light. An electrodeless light source device is provided. The microwave cavity is defined by a wall having a solid wall portion and a mesh wall portion. The solid wall portion is preferably composed of a conductive material such as, for example, copper, stainless steel, or aluminum, and the mesh wall portion is preferably transparent to light but reflects microwaves. It consists of a conductive mesh screen. Therefore, the mesh size must be appropriately determined in consideration of the wavelength of the microwave used. In a preferred embodiment, the solid wall portion is cylindrical, one end is open and the other end is closed, and likewise, the mesh wall portion is also cylindrical and has one end. Is open and the other end is closed. Preferably, the solid wall portions are connected end-to-end by connecting their open ends to the mesh wall portions, so that the solid and mesh wall portions are axially aligned along the longitudinal axis Is done. In this case, it is possible to connect the two open ends directly or indirectly via an additional element between them.

In a preferred embodiment, the solid wall portion has at least one
Number of coupling slots are formed. Most preferably, the coupling slot is formed in a side wall portion of the solid wall portion. In high light intensity applications, it is possible to provide more than one coupling slot, so that microwaves can be fed into the microwave cavity via a plurality of coupling slots. In this case, each of the plurality of coupling slots is operatively coupled via a separate waveguide to a separate microwave source, typically a magnetron. Therefore, in this configuration, it is possible to supply microwaves from a plurality of magnetrons into the same microwave cavity. However, in this case, it is desirable to arrange them so that the coupling slots maintain an orthogonal relationship. For example, if two coupling slots are provided, each coupling slot being operatively associated with a separate magnetron, the two coupling slots may be substantially aligned in a plane perpendicular to the longitudinal axis of the microwave cavity. Arrange at right angles. Further, the light emitting means preferably comprises a spherical lamp and is preferably located in the area defined by the mesh wall portion.

In accordance with another aspect of the present invention, there is provided a generally dome shaped mesh screen for use in a microwave driven electrodeless light source device. The dome-shaped mesh screen comprises a substantially cylindrical side wall and a mesh member that allows light to pass therethrough but reflects microwaves, and has a peripheral portion fixed to one end of the cylindrical side wall. And a shaped end wall. Preferably, the side wall is also at least partially composed of the mesh screen and mechanical fastening means is used to secure the dome-shaped end wall to the end of the cylindrical side wall. In one embodiment, the mechanical fastening means comprises a metal fastener or clamp. Preferably, the mesh member is comprised of tungsten, and the metal fastener is comprised of a metal or a combination of metals, such as aluminum or copper. In a preferred embodiment, the cylindrical side wall secures two opposite sides abutted by curving and curving a flat mesh member by mechanical fastening means such as, for example, metal fasteners or clamps. It is formed by clamping in place.

Such a dome-shaped mesh screen defines at least a portion of the microwave cavity, and is capable of providing a light output with increased uniformity, thus providing a spherical or approximately spherical lamp. It is particularly effective when it is located inside the dome-shaped mesh screen.
Further, since a mechanical fastening means such as a metal fastening portion or a clamp is used between the cylindrical side wall and the dome-shaped end wall, the dome-shaped mesh screen can be manufactured very easily and at low cost. Is possible. This means
This is especially true when tungsten is used for the mesh member, as tungsten is hard and relatively difficult to process. Moreover, the side walls can be curved and formed very easily by using metal fasteners. Mesh screens with such metal fasteners are also effective because they have a reinforcing structure with a high degree of structural integrity.

According to yet another aspect of the present invention, there is provided a lamp cooling system particularly suitable for use in a microwave driven electrodeless light source device. The lamp cooling device includes a plurality of nozzles located inside a microwave cavity and disposed around a lamp that absorbs microwaves and emits light. In a preferred embodiment, the plurality of nozzles are arranged such that each emits a stream of gas directed to a different point on the outer surface of the lamp, such that the lamp has its entire surface. For substantially uniform cooling. In one embodiment, the lamp is spherical in shape and is driven to rotate about a predetermined axis of rotation. In this case, the plurality of nozzles are preferably arranged around the axis of rotation, each of the plurality of nozzles being gaseous toward the spherical lamp at a different height along the axis of rotation. To cover the entire surface of the lamp.

The nozzle preferably extends externally into the microwave cavity and is preferably composed of a material that does not substantially absorb microwaves. For example, the nozzle can be formed from quartz or ceramics. Preferably, each of the nozzles is provided with a metal ferrule or fitting at its proximal end, the ferrule being mounted in a mounting hole provided in a wall defining the microwave cavity. Mated. Such a configuration,
This is advantageous because it allows the nozzle to be easily replaced in case of breakage or malfunction.

In accordance with yet another aspect of the present invention, there is provided a lamp rotation device particularly suitable for use in a microwave driven electrodeless light source device. The lamp rotating device includes a lamp that absorbs microwaves and emits light, holding means for holding the lamp in a microwave cavity, and rotatably supporting the holding means around a predetermined rotation axis. And supporting means rotatably supported at two support points separated from each other along the rotation axis. In one embodiment, the holding means comprises a linearly extending elongate stem, the longitudinal axis of which defines the axis of rotation about which the lamp is rotated. The lamp is secured to the free end of the stem. The support means preferably comprises a pair of bearings spaced apart from each other to support the stem at two points at its proximal end. Such a two-point support arrangement is very effective because the lamp is maintained in a predetermined position inside the microwave cavity, and thus the light output can be kept constant.

In one embodiment, the lamp is a spherical lamp.
Further, a sprocket is fixed to the stem by being located between the pair of bearings. An endless chain extends between a sprocket secured on the stem and another sprocket secured on the drive shaft of the motor. In such an arrangement, the lamp is prevented from wobbling and, even when driving the lamp at relatively high speeds, as may be required in some applications, the lamp is placed in a microwave cavity. Can be maintained at the intended position inside.

According to still another aspect of the present invention, there is provided a high-resolution electrodeless light source device. According to this aspect, the lamp or sphere is located in the region of the microwave cavity defined by the mesh screen, so that it is possible to irradiate light in a wider direction. Reflecting means is provided for reflecting the light emitted from the lamp in a predetermined direction so that the emitted light advances toward the image plane. Thus, the reflecting means is primarily intended to obtain as collimated light as possible towards the image plane. In a preferred embodiment, it is defined between a light beam directly incident on a selected point on the image plane from the light source and another light beam incident on the selected point after being reflected by the reflecting means. The local divergence angle is kept as small as possible. This idea is particularly important because it is this local divergence angle that determines the degree of resolution, and the smaller the local divergence angle, the higher the resolution.

In one embodiment, the reflector comprises a generally umbrella shaped reflector with a hole at the top. Preferably, the reflector is of a multi-sided configuration, ie having a plurality of facets. In other words, the umbrella-shaped reflector is preferably composed of a plurality of truncated cones, each of which has a different inclination angle. In a preferred embodiment, the angle of inclination changes stepwise and monotonically from an inner surface (inner facet) to an outer surface (outer facet). Such a face division configuration is particularly effective because it greatly facilitates design and manufacture. However, as a variant, it is also possible, if desired, for the reflector to have a continuous surface that is not plane-divided.

Furthermore, it is possible to provide an additional screen at the edge of the umbrella shaped reflector. Such additional screens help to prevent microwaves that leak through the inner mesh screen from leaking out for any reason. Such an additional screen can be made of any conductive material, such as aluminum, for example, and it can be manufactured by etching into a predetermined pattern. In other words, since this additional screen does not participate in the light emitting function, it can be formed from any material, while the inner mesh screen participates in the light emitting function, and is therefore preferably , Made of tungsten. It should be noted that the inner mesh screen can also be made of any desired material. Further, it is desirable to provide a protective glass plate to cover the entire front structure. Such a glass plate can be formed from Pyrex glass to prevent debris from hitting the operator when the lamp explodes. Such glass plates are preferably coated on the inside or on both sides with an anti-reflective coating.

EXAMPLES Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings using examples.

Referring to FIG. 1, there is schematically shown a microwave-driven electrodeless light source device 1 configured according to an embodiment of the present invention. It should be noted that the illustrated electrodeless light source device itself constitutes a new invention, and various parts and components used in the illustrated device constitute other inventions. As shown in FIG. 1, the illustrated electrodeless light source device 1 has a long microwave chamber or cavity 8 which extends vertically in FIG. The microwave cavity 8 is generally defined by a solid wall portion 8a and a mesh wall portion 8b. In the illustrated example, the solid wall portion 8a includes a cylindrical side wall 10 and the cylindrical side wall.
A circular end wall 11 fixedly attached to the top end of the cylindrical shape 10 and a cooling gas block fixedly sealed to the bottom end of the cylindrical side wall 10.
12 and has. Each of the side and short walls 10 and 11 and the cooling gas block 12 is preferably formed from a conductive material, and preferably uses aluminum for ease of processing. The cylindrical side wall 10 has a length L and a diameter D
Which are determined in relation to the frequency of the microwave used for operation. In general, the D / L ratio has a functional relationship with the frequency of the microwave used, and therefore, for a given frequency, increasing the length L of the cylindrical side wall 10 will increase The diameter D of the cylindrical side wall 10 can be reduced, and vice versa. It should be noted that in the illustrated example, the side wall 10 is cylindrical, and thus has a circular cross-sectional shape. However, if desired, the side walls 10 can be formed to have any other desired cross-sectional shape, for example, square or rectangular.

In the embodiment shown in FIG. 1, a pair of coupling slots 10a, 10a are formed in the side wall 10, and these coupling slots are connected to the respective waveguides 14l and 14r, and the waveguides are connected to each other. At the end inside each magnetron 15l
And 15r. Thus, microwaves are generated by each of the magnetrons 15l and 15r in each of the waveguides 14l and 14r, and the microwaves so generated are introduced into the microwave cavity 8 via the respective coupling slots 10a and 10a. be introduced. In the illustrated example, the two magnetrons 15l and 15r supply microwaves into the same microwave cavity 8, so that it is possible to obtain amplified microwaves inside the micro parallel cavity 8,
This contributes to obtaining high intensity light output. It should be noted, however, that more than two magnetrons may be provided to couple to the same microwave cavity 8 via separate waveguides and coupling slots to obtain higher intensity and higher output. It is possible. Or, alternatively, if a single magnetron capable of generating microwaves with sufficiently high energy is used, it may be sufficient to use such a single magnetron. . However, since the types of magnetrons available on the market are limited, it is desirable to use a multi-magnetron configuration as shown in FIG. 1 to increase the power.

In the particular configuration shown in FIG. 1, a pair of coupling slots 10a and 10a are arranged in a particular angular relationship. That is, in the preferred embodiment, the coupling slots 10a and 10a
Are arranged perpendicular to each other in a plane perpendicular to the longitudinal axis of the cylindrical side wall 10. This will be described in more detail with reference to FIG. As shown in FIG.
A pair of coupling slots 10a and 10a formed in the cylindrical side wall 10.
Are arranged so that they define an angle θ ₀ ,
And in the preferred embodiment, this angle θ ₀ is set at or near 90 °. In such an arrangement, the two microwaves introduced into the same microwave cavity 8 via a pair of coupling slots 10a and 10a are decoupled from each other, thus preventing them from interfering with each other. Have been. Therefore, two magnetrons
By using 15l and 15r, increased power is obtained in the microwave cavity 8. In the configuration shown in FIG. 2, the left waveguide 141 has three portions, namely a horizontal waveguide portion 141-1, an intermediate waveguide portion 141-2, and an inclined waveguide portion 141-3. I have. Similarly, the right waveguide 14r also has three portions, a horizontal waveguide portion 14r-1, an intermediate waveguide portion 14r-2, and an inclined waveguide portion 14r-3. Also, a tuning stub to change the effective length of the waveguide
16l or 16r is provided in the intermediate portion 141-2 or 14r-2. Angle theta ₁ are defined between the horizontal and inclined portions 14l-1 and 14l-3, and the horizontal and inclined portions 14r-
Angle theta ₂ is defined between 1 and 14r-3. Preferably, the arrangement left and right waveguides 14l and 14r are symmetrical, therefore in that case is set equal to the angle theta ₁ and the angle theta _2. In the embodiment of FIG. 2, the angle θ ₀
Is set to 90 °, these angles θ ₁ and θ
₂ is 45 ゜ each.

Returning to FIG. 1, a pair of coupling slots 10a
And 10a are located relatively close to the top of the microwave cavity 8. This arrangement makes it possible to obtain a more uniform microwave in the microcavity 8, so that
It is suitable. This may be derived from the fact that microwaves are introduced into the microwave cavity 8 at one end of the elongated microwave cavity 8 in a direction perpendicular to its longitudinal axis. However, if desired, it is also possible, as a variant, to form one or more coupling slots in the end wall 11, in which case the microwaves are parallel to the longitudinal axis of the elongated microwave cavity 8. It is introduced into the microwave cavity 8.

As shown in FIG. 1, the mesh screen portion 8b has a dome-shaped mesh screen 13. As will become clear later, the electrodeless light source device shown in FIG. 1 actually constitutes a double mesh screen system, and the dome-shaped mesh screen 13 is an inner mesh of the double mesh screen system. Make up the screen. In the embodiment shown, the dome-shaped mesh screen 13 defines or constitutes the bottom portion of the elongated microwave cavity 8. The illustrated dome-shaped mesh screen 13 is formed of a mesh member that transmits light but reflects microwaves. Therefore, the microwave introduced into the microwave cavity 8 through the pair of coupling slots 10a and 10a is prevented from passing through the mesh screen 13, as will be described later. However, light emitted by the lamp or sphere 18b is allowed to pass through the mesh screen 13 to the outside. Importantly, the mesh screen
Reference numeral 13 denotes a roughly cylindrical shape, one end of which is open and the other end of which has a dome shape. Therefore, the mesh screen 13 has a cylindrical side wall 13a and the cylindrical side wall 1a.
And a dome-shaped end wall 13b provided at one end of 3a. It has been found that such a configuration is effective for obtaining a stable operation for generating a uniform light output.

Next, the configuration of the dome-shaped mesh screen 13 will be described in detail with reference to FIGS. 3a to 3e. The mesh screen 13 has a cylindrical side wall 13a and a dome-shaped end wall 13b, each of which is formed of a mesh member that transmits light but reflects microwaves. Preferably, the mesh member is formed from woven tungsten wire. In the embodiment shown, the dome-shaped end wall 13b is secured to the lower end of the cylindrical side wall 13a by a metal fastener or clamp 13e, preferably made of a ductile metal such as aluminum, copper, or the like. Have been. As shown in FIG. 3c, the dome-shaped end wall
The peripheral portion 13b ′ of 13b is bent, and this bent peripheral portion 13b ′ is bent.
b 'can be brought into surface contact with the lower end portion of the cylindrical side wall 13a, and a metal circular fastener or clamp 13e clamps these portions of the side contacted side walls and end walls 13a and 13b. Wear or clamp. Such a circular metal fastener
Providing 13e is particularly preferred because it provides the dome-shaped mesh screen 13 with increased rigidity and strength, and therefore, even if any undesired external force is applied to the mesh screen 13. The mesh screen 13 is prevented from being deformed and can maintain its original shape. Such a shape maintaining capability is particularly important for a mesh screen used in a microwave driven electrodeless light source device. This is because it makes it possible to ensure stable operation. Otherwise, the light output may fluctuate undesirably. 3f
The figure shows a modification of the configuration shown in FIG. 3c. In this variation, the dome ring 13b "is separately formed and fixedly integrated with the periphery of the dome 13b. This configuration provides the dome 13b with its desired shape and improved structural integrity. It is effective in giving.

The side wall 13a is formed into a cylindrical configuration by bending a flat piece of mesh member and clamping the opposite side by a side metal fastener or clamp 13d. That is, as shown in FIG. 3d, the opposite side is a bent portion.
13a 'and 13a' are bent to define the surfaces 13a 'and 13a', which bends are brought into surface contact, and the side metal fasteners or clamps 13d are applied to these bent portions 13a 'and 13a'. 13a 'is mechanically held integrally. This side metal fastener 13d also contributes to providing structural rigidity and integrity to the assembled mesh screen 13. In the embodiment shown, only one side metal fastener 13d is provided, but more than one such side metal fastener 13d may be provided if desired. When two or more side metal fasteners 13d are provided, it is desirable to arrange such a plurality of side metal fasteners 13d symmetrically with the cylindrical side wall 13a around the longitudinal axis. . It should be further noted that a desired number of such side metal fasteners 13d can be provided so as not to undesirably block the passage of light.

Further, a connection metal fastener 13c is provided, as shown in FIG. 3e.
Also has a circular or ring shape, and has a cylindrical side wall 13a.
Is clamped to the top end portion of It should be noted that the connection metal fastener 13c has a flange extending radially outward, and a plurality of mounting holes 13f are formed in the flange. Thus, this connecting metal fastener 13c not only provides the mesh screen 13 with increased structural integrity, but also provides a means for connecting to related components. As shown in FIG. 1, the connecting metal fastener 13c is fixed to the top end portion of the mesh screen 13 and has a circular shape, and fits tightly into the ring-shaped cooling gas block 12. Have been combined. The block 12 effectively defines an extension of the cylindrical side wall 10 in the longitudinal direction. A ring-shaped screen bracket 34 in which a plurality of mounting holes are provided at positions corresponding to the mounting holes 13f formed in the connection metal fastener 13c is located on the flange of the connection metal fastener 13c. Then, the mesh screen 13 is fixed to the cooling gas block 12 by the bracket 34 and the screw. It should be noted that other fastening means, such as welding, soldering, sintering, etc., can be used in addition to or in place of the mechanical fastening means described above. If the fastener is made of stainless steel, it is possible to increase the strength by spot welding.

In the embodiment shown in FIG.
The lamp assembly 18 is provided inside the inside.
The lamp assembly 18 has an elongated stem 18a extending generally along the longitudinal axis of the microwave cavity 8, and a luminous bulb or lamp 18b secured to the free end of the stem 18a. The lamp 18b contains gas and solid and / or liquid additive elements, as is known to those skilled in the art, which absorbs microwaves introduced into the microwave cavity 8 and emits light. I do. In the illustrated embodiment, the lamp
18b is a spherical lamp. However, if desired, non-spherical lamps such as modified spherical lamps and circular lamps can be used. It should be noted that in the configuration shown, the lamp 18b is located inside the area defined by the mesh screen 13. Lamp 18
In order to collect as much light emitted from b as possible and obtain an increased light output, the lamp 18b is connected to a mesh screen 1
It is desirable to be located as close as possible to the third end wall 13b. In this regard, it is desirable to use a dome shaped end wall 13b. Because the lamp
Not only does it allow the 18b to be located further away from the closed end of the microwave cavity 8, but also allows the microwave to be applied uniformly to the lamp 18b.
The dome-shaped end wall 13b is particularly effective when used in combination with a lamp 18b that is spherical or substantially spherical in shape. This is because such coupling contributes to obtaining a uniform light output.

The stem 18 for holding the lamp 18b in place can be made of any desired material, but is preferably made of a material that does not absorb microwaves. For example, the stem 18a can be made of synthetic resin or glass. The stem 18a should be sufficiently rigid to allow the lamp 18b to be held in the intended position. In one example, the stem 18a
Can have a hollow configuration.

In the embodiment shown in FIG.
Are rotatably supported and are driven and rotated during operation. This aspect of the invention is described in more detail below. As shown in FIG. 1, a through hole 11a is formed in the center of the end wall 11, and a bottom bearing 20 is provided in the end wall 11. A plurality of struts 21 (only 21a and 21b are shown in FIG. 1) extend upward and are implanted in the end wall 11, and an upper plate 22 is fixed to the top of the struts 21. Have been.
An upper bearing 23 is provided at the center of the upper plate 22 and in axial alignment with the bottom bearing 20 and further with the longitudinal axis of the microwave cavity 8. On the other hand, the metal ferrule 18c is fitted on the base end of the stem 18a, and the metal ferrule 18c
Extends through and is supported by a pair of bearings 20 and 23 spaced apart from one another along the longitudinal axis of the stem 18a. As a result, the lamp assembly 18 is moved at two points, namely at the bearings 20 and 23, by the stem 18
It is rotatably supported around the longitudinal axis of a. Such a two-point support configuration is extremely useful for rotatably supporting the lamp assembly 18. This is because it contributes to keeping the lamp 18b in place even when the lamp assembly 18 is driven and rotated in the microwave cavity 8. This is very important. If the position changes when the lamp 18b is driven and rotated, the intensity of the light output changes.

As shown in FIG. 1, a sprocket 24 is fixed on a metal ferrule 18c of the lamp assembly 18. End wall 1
1 has a support plate 11b as an extension thereof, and a motor 25 is fixed to the support plate 11b. A sprocket 26 is secured on the drive shaft of the motor 25, and an endless chain 27 extends between the drive sprocket 26 and the driven sprocket 24. Therefore, the lamp assembly 18 can be driven and rotated in the microwave cavity 8 by driving and rotating the motor 25. In this case, since the rotational force is applied to the stem 18a located between the pair of spaced bearings 20 and 23, that is, the portion of the metal ferrule 18c, the lamp 18b
Is prevented from swinging when it is driven and rotated.

Next, the lamp incorporated in the apparatus shown in FIG.
A cooling system for providing a cooling gas flow to 18b will be described. In the electrodeless light source device 1 shown in FIG. 1, a cooling system for cooling the lamp 18b is provided, and a plurality of cooling systems are provided around the lamp 18b, that is, around the longitudinal axis of the lamp assembly 18. (Four in the illustrated embodiment). In FIG. 1, only two nozzle assemblies 30, 30, which are arranged opposite each other, are shown. It should be noted that in the illustrated embodiment, four nozzle assemblies 30 are disposed at equal angular intervals around the longitudinal axis of the lamp assembly 18. It should be noted that the present invention is not limited only to such a specific arrangement. Each nozzle assembly 30 has the configuration shown in FIG. 4, and has a substantially S-shaped nozzle 31 and a metal ferrule 32 fixed to the base end of the nozzle 31. I have. The nozzle 31 is preferably made of a material that is transparent, ie allows light to pass through it, and does not absorb microwaves, for example quartz. The nozzle 31 can be made of an opaque material such as a ceramic, if desired. The metal ferrule 32 is provided with a plug portion 32a and a threaded portion 32b. As will become apparent, four different types of nozzle assemblies 30 are provided, differing only in the length of the nozzles 31. That is, four different types of nozzle assemblies 30 differing only in the length of the nozzle 31 are provided.

As shown in FIG. 1, a ring-shaped cooling gas block 12 is fixed to the lower end of the cylindrical side wall 11, thereby defining a lower extension of the cylindrical side wall 11. The block 12 is provided with four mounting holes arranged at 90 ° angular intervals in the embodiment shown. The nozzle assembly 30 can be mounted at a desired position by fitting a metal ferrule or fitting 32 into a corresponding mounting hole of the block 12. The spacer 38 is fitted on the metal ferrule 32, and then the lock nut 39
Is screwed onto the threaded portion 32b of the metal ferrule 32, so that the nozzle assembly 30 is fixed in place. Next, the connector 35a of the cooling gas hose 35 is screwed to the threaded portion 32b of the metal ferrule 32. Thus, a cooling gas, such as, for example, air, can be supplied to the nozzle assembly 30 from a cooling gas source (not shown) via the hose 35. With the nozzle assembly 30 mounted in such a predetermined position, the tip of the nozzle 31 from which the cooling gas is discharged is a lamp.
18b is located against the selected luminance position. Also, since four nozzle assemblies 30 having nozzles 31 of different lengths are mounted at predetermined positions around the lamp 18b, the tips of the nozzles 31 of these four different nozzle assemblies 30 are not 18b is oriented to each selected latitude position. In this configuration, the flow of gas emitted from these four nozzle assemblies 30 is directed to different portions of the lamp 18b, so that the entire surface of the lamp 18b can be uniformly cooled. Note that lamp 18
It is also possible to provide more than four or more nozzle assemblies 30 to increase the uniformity in cooling b. Such uniform cooling of the lamp 18b is beneficial because it prevents local high stresses that may occur due to non-uniform heat distribution and may destroy the lamp 18b.

In the embodiment shown, the lamp 18b is rotated during operation, so that each part of the lamp 18b can be cooled uniformly. This is illustrated in FIGS. 5a to 5c.
A better understanding can be obtained with reference to the figures. That is, as shown in FIG. 5a, four nozzle assemblies 30a to 30a
0d is arranged around the rotation axis of the lamp 18b. 4
The tips of the nozzle assemblies are located at different heights along the rotation axis of the lamp 18b. For example, as shown in FIG. 5b, two nozzle assemblies 30a and 30b disposed on the opposite side of the rotation axis are configured such that the flow of the cooling gas discharged from the nozzle assembly 30a is at the top of the lamp 18b. A, and their tips are positioned such that the flow of cooling gas discharged from the other nozzle assembly 30b is directed to the bottom B of the lamp 18b. In addition, as shown in FIG. 5c, another two
The two nozzle assemblies 30c and 30d are arranged such that the flow of the cooling gas discharged from the nozzle assembly 30c is directed to the lower intermediate portion C of the lamp 18b, and the cooling gas discharged from the nozzle assembly 30d. Of the lamp 18b are directed to the upper intermediate portion D of the lamp 18b. As a result, the flow of cooling gas is evenly applied to the entire surface of the lamp 18b, since the lamp 18b is maintained in a rotating state during operation, so that the lamp 18b is cooled and is constant over its entire surface. Maintained at temperature. It should be noted that since a plurality of cooling gas flows are provided at different latitude portions of the lamp 18b, the amount of cooling gas to be provided to each latitude portion is changed one by one. , Lamp 18b
Can be maintained at a constant temperature. Such variable flow rates for the plurality of cooling jets is useful when the lamp 18b tends to be locally heated in certain applications.

Next, still another aspect of the present invention for obtaining uniform illumination in a wider area incorporated in the embodiment shown in FIG. 1 will be described. As shown in the embodiment of FIG.
The microwave-driven electrodeless light source device 1 has an umbrella-shaped reflector 40. A central hole is formed in a base plate 37 forming a part of the frame or the housing of the device 1, through which the mesh portion 8 b of the microwave cavity 8 extends downward. The reflector 40 is fixed to the base plate 37, and has a hole formed at the top. Therefore, the mesh portion 8b of the microwave cavity 8
Also extends through this hole in the reflector 40. A blocking member between the cooling gas block 12 and the base plate 37
33 is provided to seal the gap between the block 12 and the base plate 37. Further, between the closing member 33 and the base plate 37, and between the base plate 37 and the reflector 40.
An RF gasket 36 is provided extending to the rear surface. The provision of the RF gasket 36 effectively prevents the microwave from leaking to the outside.

As shown in FIG. 1, the reflector 40 having an umbrella shape has a multi-facet, that is, a divided surface configuration. That is, the reflectors 40 include a plurality (six in the illustrated embodiment) of reflectors 40a through 4 each defined by the peripheral surface of a truncated cone.
It has 0f. Thus, in the illustrated embodiment,
The reflective surface of each of the reflector segments 40a-40f is a flat surface in cross section. Further, the angle of inclination of each of the reflector segments 40a-40f monotonically increases from the inner segment 40a to the outer segment 40f.
Importantly, this multi-faceted reflector
40 is configured to provide high-resolution light illumination over a large area on the image plane. This aspect of the invention is described in more detail below with reference to FIG.

In the configuration shown in FIG. 7, only three reflector segments 40a to 40c are shown for simplicity. As shown in FIG. 7, the rotation axis of the lamp 18b defines the irradiation direction or the central axis of the light emitted by the light source device 1. Light emitted from lamp 18b is reflected by one of the reflector segments to a selected point on image plane 50.
Either is incident on 50b or 50c, or is directed directly to that selected point 50b or 50c. The angle θ formed between these two beams incident on the selected point 50b or 50c
(That is, θ ₇ or θ ₆ in the illustrated example) is defined as a local divergence angle. Near the center around the central axis, this local divergence angle θ (ie, in the illustrated example,
θ ₅ ) is defined by the two beams reflecting from opposite points of the same reflector segment. This local divergence angle plays an important role in determining the degree of resolution,
The smaller the local divergence angle, the higher the resolution. The reflector 40 divided on the main surface makes it possible to minimize the local divergence angle as much as possible while maximizing the light intensity. It is further important that this local divergence angle be kept substantially constant over the area of interest in the image plane 50. If the local divergence angle is maintained substantially constant over the area of interest, it is possible to obtain a substantially constant resolution over the area of interest. In other words, if the local divergence angle is substantially uniform over the area of interest on the image plane 50, then θ
The condition of ₅ ≒ θ ₆ ≒ θ ₇ holds.

Therefore, the reflector 40 can provide uniform, high-intensity and high-resolution light irradiation over a wide area on the image plane 50. Accordingly, the resulting light irradiation from the device 1 is substantially collimated and parallel to the irradiation direction. It should be noted that the reflector 40 is large in size (i.e., has a large diameter so that light reflected from the reflector 40 is substantially substantially accurate over a large area on the image plane 50). It should also be noted that the local divergence angle is kept as small as possible and remains substantially constant over a large area on the image plane 50. However, it is also possible for the reflector 40 to have a continuous reflecting surface if desired, without splitting, but a split-segment configuration is preferred as it greatly simplifies design and manufacture. This means that
This is especially true when the reflector 40 is made of metal, because the machining is significantly facilitated when the reflector 40 has a surface-divided configuration.

In the electrodeless light source device 1 shown in FIG.
An outer screen 42 is also provided that is secured to the outer flange of 40. This outer screen 42 does not participate in the light emitting function, it prevents microwaves that may be emitted from the microwave cavity 8 from being emitted to the outside. Mesh portion 8b of microwave cavity 8
Since is defined by the mesh member, microwaves may be emitted from the microwave cavity 8.
Even in such a case, the outer screen 42 functions to prevent such microwaves from leaking outside. In one example, the outer screen 42 can be formed as a screen formed by etching as shown in FIG. In this case, the outer screen 42
Can be formed by etching a pattern such as a honeycomb pattern shown in FIG. 6 from aluminum or the like. Such a dual screen configuration is effective in preventing microwaves from leaking into the atmosphere.

Further, as shown in FIG. 1, a protective glass plate 44 is provided at the front end of the apparatus 1. This protective glass plate 44 prevents dust and dirt from adhering to the reflector 40 and the inner mesh screen 13, and if the lamp 18b explodes for any reason, the debris collides with a nearby operator. It works to prevent that.
The glass plate 44 can be formed from Pyrex glass or any other glass material that allows the transmission of light therethrough. Since the combined light radiation obtained from the device 1 is of high light intensity and relatively collimated, the light is reflected by the surface of the glass plate 44, thereby increasing the local divergence angle and reducing the splitting power. It becomes a tendency. To cope with this situation, an antireflection film 44a is formed on the inner surface of the glass plate 44, preferably on both side surfaces. According to this configuration, the combined light irradiation passes through the glass plate 44 without being reflected, and therefore, the local divergence angle can be kept to a minimum.

Effects As described above, according to the present invention, there is provided a microwave-driven electrodeless light source device capable of supplying a stable light output for a long period of time. Further, a high power microwave cavity capable of providing high intensity light output is provided. Furthermore, the light output is uniform and high resolution over a large area of interest, which was not possible with any of the conventional electrodeless light source devices.

As described above, the specific embodiments of the present invention have been described in detail. However, the present invention should not be limited to these specific examples, and various modifications may be made without departing from the technical scope of the present invention. Is of course possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the overall configuration of a microwave-driven electrodeless light source device 1 configured based on one embodiment of the present invention, and FIG. 2 is configured based on one embodiment of the present invention. Schematic diagram showing a two magnetron system in which two separate magnetrons are coupled to the same microwave cavity,
3a to 3e are schematic views showing a dome-shaped mesh screen configured according to one embodiment of the present invention,
FIG. 3f is a schematic view showing a modification of FIG. 3c, FIG. 4 is a schematic view showing a nozzle assembly constructed based on one embodiment of the present invention, and FIGS. FIG. 6 is a schematic view showing an arrangement of four nozzle assemblies in a cooling system configured according to an embodiment of the present invention; FIG. 6 is an etched outer screen configured according to an embodiment of the present invention; FIG. 7 is a schematic diagram useful for explaining the principle of a reflector configured according to an embodiment of the present invention. (Explanation of symbols) 1: Microwave-driven electrodeless light source device 8: Microwave cavity 8a: Solid wall portion 8b: Mesh wall portion 10: Cylindrical side wall 11: End wall 12: Cooling gas block 13: Dome-shaped mesh Screen 14: Waveguide 15: Magnetron 18: Lamp assembly 18a: Stem 18b: Lamp (sphere) 20,23: Bearing 30: Nozzle assembly 40: Reflector 42: Outer screen 44: Glass plate

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Andrew Day. Harbourne United States, Maryland 21754, IJamesville, Fair Greenway 5211 (56) References JP-A-60-235303 (JP, A) Patent 107670 (JP, C2)

Claims (6)

(57) [Claims] 1. A solid wall portion having a solid end wall and a solid side wall, and a mesh wall portion formed of a mesh having a mesh end wall and a mesh side wall and transmitting light but reflecting microwaves. A microwave cavity is defined with the respective open ends facing each other, and at least one coupling slot for introducing microwaves into the microwave cavity is formed in the solid wall portion. Light emitting means for absorbing microwaves and emitting light is located within said microwave cavity, said light emitting means being such that the local divergence angle is substantially constant over a predetermined area in the image plane. A portion of the light emitted from the mesh and passing through the mesh and directed in a direction exceeding a predetermined direction at a predetermined angle with respect to the irradiation axis is reflected in substantially the same direction as the irradiation axis. High resolution electrodeless light source device characterized by reflecting means is provided in order to. 2. A high-resolution electrodeless light source device according to claim 1, wherein said mesh substantially surrounds said light emitting means. 3. A high-resolution electrodeless light source device according to claim 1, wherein said reflecting means has a reflecting surface having a substantially umbrella shape. 4. A high resolution electrodeless light source according to claim 3, wherein said reflective surface has a plurality of segments each defined by the circumference of a truncated cone. apparatus. 5. The high-resolution electrodeless light source device according to claim 4, wherein each of said segments has a different inclination angle with respect to said irradiation axis. 6. The high-resolution electrodeless light source device according to claim 5, wherein said inclination angle gradually changes from inside to outside of said umbrella-shaped reflecting surface.