JP4102395B2 - High pressure discharge lamp manufacturing method and lamp unit - Google Patents

Description

  The present invention relates to a method for manufacturing a high-pressure discharge lamp and a lamp unit including the high-pressure discharge lamp manufactured by the manufacturing method.

  High-pressure discharge lamps, among others, short arc type high-pressure discharge lamps having a short distance between electrodes are suitably used as light sources for liquid crystal projectors and the like. The short arc type high-pressure discharge lamp literally has a short arc length and can realize a pseudo-point light source, which improves the light collection efficiency when used as a lamp unit in combination with an optical system such as a concave reflector and is projected onto the screen. This is because the brightness of the screen can be increased.

Conventionally, a high pressure discharge lamp is manufactured, for example, as follows.
After heating and softening the longitudinal central portion of the straight tube-shaped glass tube, the softened central portion becomes the cavity portion in a mold having a substantially spherical or substantially spheroid shaped cavity portion. The glass tube is set so as to be positioned, one end of the glass tube is closed, compressed air or the like is fed from the other end, and the central portion is bulged to form a substantially spherical shape or a substantially spheroid shape. As a result, a glass tube is produced in which the side tube portions are extended from both ends of the main tube portion having a substantially spherical shape or a substantially spheroid shape (see Patent Document 1).

  Then, the first electrode assembly in which the electrode, the metal foil, and the lead wire are joined in this order from one side tube portion of the glass tube manufactured in this way is used, and the electrode is the main tube with the electrode at the head. After inserting until one side tube portion is positioned, the one side tube portion is sealed, and then, after the inclusion is inserted from the other side tube portion, alignment with the first electrode assembly (distance between the electrodes) The second electrode assembly having the same configuration as the first electrode assembly is inserted, the other side tube portion is sealed, and the main tube portion is hermetically sealed. (See Patent Document 2).

As a result, a high-pressure discharge lamp is produced in which the tips of the pair of electrodes are arranged substantially opposite to each other in the hermetically sealed main pipe portion.
The above-mentioned sealing is performed by, for example, shrink-sealing, for example, the side tube portion where the metal foil is located after the side tube portion is heated and softened.
JP-A-3-147230 JP 2002-298738 A

By the way, in recent years, as the performance of liquid crystal projectors and the like has been improved, a high-pressure discharge lamp with a shorter arc length has been demanded. For example, in a small lamp of 100 W to 150 W, the distance between the electrodes is 1 mm or less. Is required.
However, in the above conventional manufacturing method, the formation of the main pipe part and the sealing of the side pipe part are carried out by plastically deforming the glass pipe in a softened state. Variations in the shape of the inner surface of the part or variations in the sealing position may occur. As a result, the volume of the hermetic sealing space (discharge chamber) of the main pipe portion varies. The variation in volume appears as a variation in lamp luminance, and as a result, the luminance of the screen projected on the screen varies from lamp to lamp.

As described above, when the stricter accuracy is required as the distance between the electrodes is shortened, in the conventional manufacturing method described above, the variation in luminance becomes intense, and it is attempted to keep the product quality constant. Then, the yield will fall remarkably.
In view of the above-described problems, the present invention provides a method for manufacturing a high-pressure discharge lamp capable of suppressing unevenness in luminance between manufactured lamps as compared with a conventional manufacturing method, and a lamp including a high-pressure discharge lamp manufactured by the manufacturing method. The purpose is to provide units.

  In order to achieve the above object, a method of manufacturing a high-pressure discharge lamp according to the present invention includes a first electrode and a glass tube in which first and second side tube portions are extended from both ends of a main tube portion. In a state where one electrode shaft element body including a portion to be a portion and a portion to be a second electrode is inserted so that the portions to be the first and second electrodes are located in the main pipe portion, A preparatory step of preparing a sealed one side tube portion and a second side tube portion, and a volume size in a main tube portion forming a discharge chamber in a state where the both side tube portions are sealed; Between the measurement step of measuring, the comparison step of comparing the measurement result in the measurement step with the reference volume of the main section, and the portion to be the first electrode and the portion to be the second electrode Depending on the comparison result in the cutting step of cutting the electrode shaft element by laser and the comparison step, An inter-electrode distance setting step for setting the inter-electrode distance by widening the facing distance by melting the tip portion of the first electrode portion and the second electrode portion separated by cutting. And

In the inter-electrode distance setting step, the inter-electrode distance is increased as the volume measured in the measurement step relative to the reference volume is relatively large.
Furthermore, the volume measured in the measurement step is Vx, the reference volume is Vs, the inter-electrode distance as a reference between the first electrode and the second electrode is Ls, and the finally obtained inter-electrode distance Is set to Lx, in the inter-electrode distance setting step, according to the comparison result in the comparison step, when Vx is larger than Vs, Vx is substantially equal to Vs so that Lx is longer than Ls. In this case, when Vx is smaller than Vs so that Lx is almost equal to Ls, the tip portions of the first and second electrodes are melted and degenerated so that Lx is shorter than Ls. It is characterized by making it.

Further, the melting in the inter-electrode setting step is performed by irradiating a tip end portion of a portion serving as the first electrode and a tip portion of a portion serving as the second electrode with a laser beam. .
Alternatively, the melting in the inter-electrode setting step is performed by discharging between a tip portion of a portion serving as the first electrode and a tip portion of a portion serving as the second electrode. .
In order to achieve the above object, a lamp unit according to the present invention has a concave reflecting mirror, and the center between electrodes of the high-pressure discharge lamp manufactured by the manufacturing method described above is located at the focal position of the concave reflecting mirror. Thus, the high-pressure discharge lamp is provided.

  According to the manufacturing method of the high-pressure discharge lamp according to the present embodiment, the distance between the electrodes is ensured according to the size of the volume in the main pipe part to which the electrode shaft element is sealed. It becomes possible to suppress the luminance unevenness between the two.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a high-pressure mercury lamp 10 (hereinafter simply referred to as “lamp 10”) to be manufactured by the manufacturing method according to the present embodiment. FIG. 1 is a view in which only a glass bulb 12 described later is cut along a plane including its axis. Moreover, the scale between each component is not unified in all the drawings including FIG.

As shown in FIG. 1, the lamp 10 includes a glass bulb 12 having a discharge chamber (light emitting space) 14 hermetically sealed. The glass bulb 12 is made of quartz glass.
Further, the lamp 10 has a pair of electrodes 16 and 18 which are disposed in the discharge chamber 14 with their tip portions facing each other. The first electrode 16 is formed by winding a coil 22 around an electrode shaft 20. Similarly, the second electrode 18 is formed by winding a coil 26 around an electrode shaft 24.

The base ends of the electrode shafts 20 and 24 are supported by the glass bulb 12, and each of the electrode shafts 20 and 24 extends substantially coaxially to the discharge chamber 14, and each coil is formed at the tip portion thereof. 22 and 26 are wound. Each of the coils 22 and 26 is provided to exhibit an appropriate heat dissipation function and prevent overheating of the electrodes when the lamp 10 is turned on.
In addition, a part of the opposing tip portion of the first electrode 16 and the second electrode 18 is processed into a substantially hemispherical shape to form heads 28 and 30 as described later. The reason for processing into a substantially hemispherical shape is to concentrate the discharge at the time of lighting as much as possible at the tip of the head to prevent a so-called arc jump phenomenon in which the arc is displaced randomly. Of course, in order to prevent the arc jump phenomenon, the tip shape is “substantially hemispherical” as an example, and may be, for example, substantially spherical or substantially conical.

The distance between the tips of both heads 28 and 30 in the tube axis direction of the glass bulb 12, that is, the inter-electrode distance D is adjusted in the range of 1.0 to 1.5 mm as described later. The electrode shafts 20 and 24 have a diameter of 0.4 mm, and the coils 22 and 26 have an outer diameter of 1.2 mm. The electrode shafts 20 and 24 and the coils 22 and 26 are both made of tungsten.
The end portions of the electrode shafts 20 and 24 opposite to the head portions 28 and 30 are joined to one end portions of strip-shaped metal foils 32 and 34. Each of the pair of metal foils 32 and 34 is made of molybdenum foil.

  One end portion of the first external lead wire 36 is joined to the other end portion of the first metal foil 32, and a second external portion is connected to the other end portion of the second metal foil 34. Lead wire 38 is joined. The end portions of the first and second external lead wires 36 and 38 opposite to the metal foils 32 and 34 are exposed from the glass bulb 12, and power is supplied from the end portions, whereby the lamp 10 can be turned on. Both the first and second lead wires are made of molybdenum wires.

The glass bulb 12 is sealed mainly at portions corresponding to the metal foils 32 and 34, and the hermetically sealed discharge chamber 14 is formed.
The discharge chamber 14 is filled with mercury 40 as a luminescent material and a rare gas (not shown) such as argon, krypton, and xenon as a starting aid, and a halogen material (not shown) such as iodine and bromine. Yes. The halogen substance functions to suppress blackening of the glass bulb by returning to the electrodes 16 and 18 without attaching tungsten evaporated from the electrodes 16 and 18 to the inner surface of the quartz glass bulb 12 by a so-called halogen cycle. Is to be enclosed.

Then, the manufacturing method of the lamp | ramp 10 which consists of said structure is demonstrated.
As shown in FIG. 2, first, a glass tube 42 for the lamp 10 (hereinafter simply referred to as “glass tube 42”) and an electrode assembly 44 are prepared.
The glass tube 42 is a member that becomes the glass bulb 12, for example, a main tube portion 46 having a substantially spherical shape or a substantially spheroid shape, and a cylindrical first side extending from both ends thereof. It has a pipe part 48 and a second side pipe part 50. Needless to say, the glass tube 42 is made of quartz glass.

A method of manufacturing the glass tube 42 will be described with reference to FIG.
First, as shown in FIG. 3A, while the glass tube 41 having one end closed and the other end opened is rotated around the tube axis, the portion where the main tube portion 46 is to be formed is burnered. At 43, the outer periphery is heated and softened.
Next, as shown in FIG. 3 (b), a mold 49 is formed of an upper mold 45 and a lower mold 47, and in the closed state, cavity portions 45A and 47A having the same shape as the outer periphery of the main pipe portion 46 are formed. Then, the softened portion is sandwiched.

Then, as shown in FIG. 3 (c), a compressed gas composed of an inert gas is blown from the open end portion to bulge the softened portion, so that the outer periphery of the glass tube 41 extends along the inner surfaces of the cavity portions 45A and 47A. Accordingly, the main pipe portion 46 is formed. Thereafter, both end portions of the glass tube 41 are cut at appropriate positions to complete the glass tube 42.
Returning to FIG. 2, in the electrode assembly 44, the metal foils 32 and 34 are bonded to both ends of one metal shaft 52, and the external lead wires 36 and 38 are bonded to the metal foils 32 and 34. It will be. Further, a pair of coils including a first coil 54 and a second coil 56 are extrapolated to the metal shaft body 52. Here, what is formed by extrapolating the first coil 54 and the second coil 56 to the metal shaft 52 is processed into the first electrode 16 and the second electrode 18 as described later. .

  The glass tube 42 configured as described above is set on a jig 58, and as shown in FIG. 2, the electrode shaft assembly 44 is placed on the glass tube 42, and the first coil 54 and the second coil 56 are the main tubes. The electrode 46 is inserted so as to be positioned at the part 46 [electrode assembly inserting step]. More specifically, the electrode shaft assembly 44 is inserted until the middle of the first coil 54 and the second coil 56 in the tube axis direction of the glass tube 42 is located in the middle of the main tube portion 46.

Next, as shown in FIG. 4, a part of each of the side tube portions 48 and 50 is sealed, and the main tube portion 46 is hermetically sealed to form the discharge chamber 14 [sealing step]. The hermetic sealing is mainly performed at the portion where the metal foils 32 and 34 are located.
The sealing step can be realized by the following procedure, for example.
First, the inside of the glass tube 42 is depressurized (for example, about 20 kPa), and the metal foil 32 of the first side tube portion 48 is located while rotating the glass tube 42 around the tube axis 60 in this depressurized state. Is heated with a burner (not shown) and softened. If it does so, the softened part of the 1st side pipe part 48 will shrink | contract, a part of inner surface of the said 1st side pipe part 48 and the metal foil 32 will closely_contact | adhere, and sealing will be made | formed.

Next, after introducing the mercury 40, the rare gas (not shown), and the halogen substance (not shown) into the glass tube 42 (in the main pipe portion 46), the second side tube portion 50 is moved to the first side tube 50. The sealing process is completed by sealing in the same manner as in the case of the side tube portion 48.
When the sealing step is completed, the metal shaft body 52 is fixed in a state in which the shaft core substantially coincides with the tube shaft 60 of the glass tube 42. That is, the axis of the metal shaft body 52 substantially coincides with the central axis of the main pipe portion 46.

When the sealing process is completed, the volume of the discharge chamber 14, that is, the volume of the main tube 46 is measured. Here, “volume size” does not mean the absolute value of the volume measured by “cc” or “cm ³ ” but the relative size of the space to be measured. However, absolute conversion is possible by converting the camera scale to the actual scale.

FIG. 5 is a block diagram showing a schematic configuration of the system 100 for measuring the volume size.
The size of the volume is determined by photographing a longitudinal section of the main pipe section 46 with X-rays. Therefore, the measurement system 100 includes an X-ray tube 102 that irradiates X-rays toward the main pipe unit 46, an X-ray image intensifier 104 that converts an X-ray image obtained by the irradiation into a visible image, and a conversion An area CCD (hereinafter simply referred to as “CCD”) 106 that captures the visible image.

Here, in measuring the size of the volume, an imaging method using X-rays that is not easily affected by the refractive index of the glass is used. However, there is no particular limitation as long as the measurement is possible. An infrared camera, an ultraviolet camera, or a visible camera (monochrome / color) may be used.
A lamp 10 used for imaging (which has not been completed during manufacture but will be described as a lamp 10 for convenience) is attached to a jig 108 that is rotatably held. One end of the lamp 10 attached to the jig 108 is connected to the output shaft 112A of the stepping motor 112 via a universal joint 110 made of a rubber tube or the like.

In the embodiment of the present invention, the lamp 10 is rotated. However, the X-ray tube 102 on the imaging side, the X-ray image intensifier 104, and the CCD 106 may be rotated.
Reference numeral 114 denotes a control device that includes a personal computer or the like and calculates the volume of the main tube 46 from the image captured by the CCD 106 and controls the rotation angle of the stepping motor 112.

The image capturing unit 116 captures an image captured by the CCD 106 in accordance with an instruction from the main control unit 130 described later. The state of the captured image is shown in FIG. Because of the X-rays, the metal part is black and the glass part is photographed with light and shade according to its thickness. In FIG. 6 and subsequent figures, illustration of mercury 40 in the main pipe portion 46 is omitted.
The image analysis unit 118 specifies the outer periphery 120 of the discharge chamber 14 by edge detection by a general image recognition process.

FIG. 6B is a diagram showing only the outer periphery (edge) 120, and a glance divided into small squares indicates one pixel. As an example, imaging is performed by a CCD 106 having 250,000 to 1 million pixels. Needless to say, the size of one pixel in FIG.
When detecting the edge 120, the image analysis unit counts the number of pixels surrounded by the edge 120 (hereinafter referred to as “in-edge pixel”), and outputs the counted number to the volume calculation unit 122 (FIG. 5). In FIG. 6B, pixels within the edge are partitioned by solid lines. The counting is performed as follows. The pixel columns arranged in n columns in the X-axis direction are scanned from the first column to the n-th column in order, and the number of pixels in the edge is counted for each column. The count result is output to the volume calculation unit 122 (FIG. 5) for each column. The output result attached to one image is “p1, p2,..., Px,. Of course, the number near both ends in the X-axis direction is “0” in most cases.

The above imaging is performed m times by changing the rotation angle around the axis of the lamp 10 by an equal angle (an angle obtained by dividing 360 degrees into m). The image analysis unit 118 performs the above-described counting for each imaging, and outputs the counting result to the volume calculation unit 122.
As an example, the volume calculation unit 122 calculates the length of one pixel in the Y-axis direction to the average number in each column obtained by dividing the total number of pixels in the same column by m from m imaging results by the following formula. Multiply the length r to calculate the lengths P1 to Pn in the Y-axis direction for each column.

In the following equation, the volume cross-sectional shape is approximated as a circle.
P1 = {(p1 + p1 +... + P1) / m} × r
P2 = {(p2 + p2 + ... + p2) / m} * r
:
Px = {(px + px +... + Px) / m} × r
:
Pn = {(pn + pn +... + Pn) / m} × r
Next, the volume calculation part 122 calculates the volume size Vd of the main pipe part 46 by the following equation.

Vd = π {(P1 / 2) ² + (P2 / 2) ² + ... + (Px / 2) ² + ... + (Pn / 2) ² }
The volume calculation unit 122 outputs the calculation result Vd (hereinafter referred to as “measured volume Vd”) to the comparison determination unit 124.
The comparison / determination unit 124 outputs the determination result described in the middle row based on the determination criteria described in the upper row of Table 1. V1 and V2 are values having a relationship of V1 <Vs <V2 when the design volume of the main pipe portion 46 of the lamp 10 is Vs (hereinafter referred to as “reference volume Vs”).

すなわち、比較判定部１２４は、Ｖ１≦Ｖｄ≦Ｖ２の場合は、本管部４６の容積はほぼ設計通りに確保されているとみなして「標準」の判定をし、Ｖｄ＜Ｖ１の場合、本管部４６の容積は設計基準よりも狭くなっているとみなして「狭」の判定をし、Ｖ２＜Ｖｄの場合は、本管部４６の容積は設計基準よりも広くなっているとみなして「広」の判定をする。ここで、測定容積Ｖｄが基準容積Ｖｓと完全に一致することは、あまり生じないと思われるので、基準容積Ｖｄに対しある幅（Ｖ１以上Ｖ２以下）に入っている場合には、測定容積Ｖｄは基準容積Ｖｓとほぼ等しいとして「標準」の判定をすることとしたのである。

That is, when V1 ≦ Vd ≦ V2, the comparison / determination unit 124 determines that the volume of the main pipe unit 46 is almost as designed, and determines “standard”. If Vd <V1, It is determined that the volume of the pipe portion 46 is narrower than the design standard, and the determination is “narrow”. If V2 <Vd, the volume of the main pipe portion 46 is considered to be wider than the design standard. Judge “Wide”. Here, since it seems that it does not occur that the measurement volume Vd completely coincides with the reference volume Vs, when the measurement volume Vd falls within a certain width (V1 or more and V2 or less) with respect to the reference volume Vd, the measurement volume Vd. Is determined to be “standard” because it is substantially equal to the reference volume Vs.

The comparison determination unit 124 outputs the determination result to 130, and the main control unit 130 causes the display unit 126 to display the determination result. The motor control unit 128 controls the rotation of the stepping motor 112 in accordance with an instruction from the main control unit 130. The main control unit 130 comprehensively controls each of the above-described units 116 to 128 and the CCD 106.
Following the determination result, a cutting step of laser cutting the metal shaft body 52 is performed.

FIG. 7A is an enlarged view of the main pipe portion 46 and the vicinity thereof at the end of the determination (at the end of the sealing process).
In the cutting step, a known YAG laser oscillator (not shown) is used.
A laser beam LB1 focused to a spot diameter of 0.1 mm is irradiated approximately perpendicularly to the axis of the metal shaft 52 by an optical system (not shown) as shown in FIG. Since the beam diameter is smaller than the diameter of the metal shaft body 52, the laser beam LB1 is relatively moved in the direction perpendicular to the axis of the metal shaft body 52 as shown in FIG. I do.

  As shown in FIG. 8A, cutting can be performed with a cutting width DL substantially equal to or less than the beam diameter, and the cutting width is substantially uniform in the moving direction of the laser beam LB1. . That is, the cutting in the cutting process of the present embodiment is clearly a cutting in which a member is melted and the member is separated by its surface tension (hereinafter, such cutting is referred to as “melt cutting”). A different mode of cutting is used. Furthermore, in melt cutting, the tip portion after cutting is rounded due to surface tension, and the cutting width is not uniform, whereas the cutting of the present embodiment is a cutting with a substantially uniform width. It is.

  Further, if the metal shaft body 52 is to be cut, as shown by a broken line in FIG. 7A, it is conceivable that the metal shaft body 52 is irradiated with a laser beam from an oblique direction (hereinafter simply referred to as “ Sometimes referred to as “diagonal irradiation”. However, in this case, there is a high possibility that the laser beam irradiation position on the metal shaft 52 will vary for the following reasons. In each figure, the main pipe portion 46 is drawn in the shape of a spherical shell having a uniform thickness for convenience. However, in actuality, the thickness is not uniform for manufacturing reasons, and varies from individual to individual. The variation in thickness increases as it approaches the side tube portions 48 and 50, and the oblique irradiation passing through the position 46B near the side tube portion 50 is affected by the variation in thickness and in the direction of refraction when passing through the glass. Variations occur and the positional relationship between the irradiation position and the focal point and the workpiece varies. Therefore, in the present embodiment, the laser beam is emitted from the position 46A where the influence due to the variation in the thickness of the main pipe portion 46 is the least, that is, from the portion that bulges most with respect to the axis of the metal shaft body 52 (tube axis 60). It is supposed to be irradiated.

  In the above example, the circularly focused beam is moved and cut. However, the present invention is not limited to this. For example, as shown in FIG. The laser beam may be shaped and irradiated on a rectangular cross section having a side of 0.1 mm (LB2). This makes it possible to cut the laser beam LB2 without moving it. Even in this case, the cutting width is substantially uniform as in the case described above.

The metal shaft body 52 is cut into two by the cutting step, so that the first electrode shaft body 52A to be the first electrode 16 and the second electrode shaft body 52B to be the second electrode 18 are formed. (FIG. 8 (a)), this time, a melting step for setting the interelectrode distance is performed.
As shown in FIG. 8B, the tip portions of the electrode shaft bodies 52A and 52B cut and separated in the cutting step are irradiated with laser beams LB3 and LB4 to melt the tip portions. This amount of melting can be appropriately adjusted depending on the beam output and / or the irradiation time.

That is, when the beam output is constant and the determination result is “standard”, the irradiation time is Ts [second], and when the determination result is “narrow”, the determination result is T1 [second] shorter than Ts. In the case of “wide”, T2 [seconds] is longer than Ts.
By irradiation with the laser beams LB3 and LB4, the tip portions of the electrode shaft bodies 52A and 52B are melted, and the melted portions are degenerated toward the base ends (support ends) due to surface tension, and FIG. As shown in FIG. The distance between the electrodes is set according to the amount of degeneration. The degeneration amount is proportional to the melting amount, and the melting amount is proportional to the laser beam irradiation time, for example. Therefore, the distance between the electrodes is adjusted according to the irradiation time of the laser beam according to the volume of the main pipe portion 46. When the beam output is constant, the correlation between the irradiation time and the degeneracy amount can be obtained empirically by experiment.

In this case, if the determination result is “wide” and the volume of the main pipe portion 46 is larger than the design standard, the density of mercury vapor is reduced, and the luminance is lowered if the standard inter-electrode distance Ds is set. Resulting in. Therefore, the distance between the electrodes is set to D2, which is longer than Ds (see Table 1).
On the other hand, if the determination result is “narrow” and the volume of the main pipe portion 46 is smaller than the design standard, the density of mercury vapor becomes excessively high, and the standard inter-electrode distance Ds is set. Luminance increases too much, causing quality variation problems. Therefore, the distance between the electrodes is set to D1, which is shorter than Ds (see Table 1).

When the determination result is “standard” and the volume of the main pipe portion 46 is almost as designed, the inter-electrode distance Ds is set as designed (see Table 1).
Here, the interelectrode distances D1, Ds, and D2 are, for example, 1.0 ≦ D1 <1.2, 1.2 ≦ Ds ≦ 1.3, and 1.3 <D2 ≦ 1.5 (units). Is mm).
As a result, the inter-electrode distances D1, Ds, and D2 are set according to the volume of the main pipe portion 46, so that variations in luminance among manufactured lamps can be suppressed as compared with the conventional art. . The conditions such as the output and irradiation time described above are appropriately determined according to the material to be melted (electrode shaft element, coil), the amount of melting, and the like.
As described above, when the volume of the main pipe portion 46 fluctuates, the density of mercury vapor fluctuates, and as a result, the desired luminance cannot be obtained (if the distance between the electrodes remains constant), the above-mentioned In the example, the distance between the electrodes is adjusted according to the size of the volume of the main pipe portion 46 (the amount of fluctuation of the measurement volume Vd from the reference volume Vs).

Here, the density of the mercury vapor is determined by the size of the space (the place where no object is present) in the main pipe section 46 (discharge chamber 14). In the above example, the first and second electrodes 16 are used. , 18 (however, the portion existing in the discharge chamber 14), the distance between the electrodes is adjusted using the volume (reference volume Vs, measurement volume Vd) of the main pipe portion 46, which does not take into account the volume. Then there seems to be a problem.
However, the problem here is the variation of the space, and the volume of the first and second electrodes 16 and 18 (however, the portion existing in the discharge chamber 14) can be regarded as substantially constant, so that the space is concerned. The variation in the size of is the same as the variation in the measurement volume Vd, so there is no problem. Furthermore, when the volume of the main pipe portion 46 is the reference volume Vs, a space is secured so that the mercury vapor has an appropriate density (substantially according to the design standard).

  Of course, the volume of the main pipe portion 46 used for adjusting the distance between the electrodes may be determined in consideration of the volumes of the first and second electrodes 16 and 18 (the portion existing in the discharge chamber 14). That is, an average value (hereinafter simply referred to as “electrode volume”) of the volume of the first and second electrodes 16 and 18 that will be present in the discharge chamber 14 is obtained in advance. Vs ′ obtained by subtracting the electrode volume from the reference volume Vs may be used as the reference volume, and Vd ′ obtained by subtracting the electrode volume from the measurement volume Vd may be used as the measurement volume.

  The irradiation with the laser beam LB3 and the irradiation with the laser beam LB4 in the irradiation step may be performed simultaneously or sequentially. In the case of simultaneous, it is not always necessary to use two laser oscillators. One laser beam emitted from one laser oscillator may be split into two by a half mirror or the like to create the laser beam LB3 and the laser beam LB4.

  As described above, by irradiation with the laser beams LB3 and LB4, a part (about 1 to 2 turns) of the coils 54 and 56 is also melted, and the melted part is moved to the base end (support end) side by the surface tension. And is rounded so as to have a substantially hemispherical surface as shown in FIG. Any of the required interelectrode distances D1, Ds, and D2 (FIG. 8C) is set by the degeneration. When the melted portion is solidified, the electrode 16 and the electrode 18 in which the coil 22 and the electrode shaft 20 and the coil 26 and the electrode shaft 24 are integrally joined are completed.

In the example described above, the tip portions of the electrode shaft bodies 52A and 52B are irradiated with a laser beam and melted. However, the melting method is not limited to laser beam irradiation.
As shown in FIG. 9A, the first external lead wire 36 and the second external lead wire 38 are connected to the lighting device 132 and melted by discharging between the electrode shaft bodies 52A and 52B for a predetermined time. You may let them. A known device can be used as the lighting device 132.

When power is supplied by the lighting device 132, as shown in FIG. 9B, a discharge occurs between the tips of the electrode shaft base bodies 52A and 52B, and the tip portions melt.
In this case, the feed power W is adjusted according to the determination result. That is, when the determination result is “standard”, the power is Ws [W], when the determination result is “narrow”, W1 [W] is smaller than Ws, and when the determination result is “wide”, It is assumed that W2 [seconds] is larger than Ws. This is because if the discharge time is constant, the melting amount (degeneration amount) is proportional to the feed power.

  The tip portion melted by the discharge is contracted to the base end (support end) side by the surface tension as in the case of melting by laser, and has a substantially hemispherical surface as shown in FIG. So rounded. Any one of the interelectrode distances D1, Ds, and D2 required by the degeneration (see FIG. 8C) is set, and when the melted portion is solidified, the coil 22 and the electrode shaft 20, and the coil 26 and the electrode shaft 24 are connected. The electrode 16 and the electrode 18 that are integrally joined to each other are completed as in the case of laser melting.

  As described above, according to the present embodiment, the glass tube 42 in which the side tube portions 48, 50 are extended from both ends of the main tube portion 46, the portion serving as the first electrode 16 and the second electrode 16. An insertion step of inserting one metal shaft body 52 including a portion to be the electrode 18 so that the portions to be the first and second electrodes 16 and 18 are located in the main pipe portion 46; A sealing step of sealing the main pipe portion 46 by sealing the both-side pipe portions 48 and 50; a measuring step of measuring the volume of the sealed main pipe portion 46; The metal shaft body 52 is divided between the portion to be the electrode 16 and the portion to be the second electrode 18, and the interelectrode distance is set according to the size of the volume measured in the measurement step. A high-pressure discharge lamp is manufactured through the distance setting step.

  In the inter-electrode distance setting step, the metal shaft body 52 is cut into two parts by a laser between a portion to be the first electrode 16 and a portion to be the second electrode 18, and the first electrode A cutting step for creating the shaft element body 52A and the second electrode shaft element body 52B, and the tip portions of the opposing sides of the first electrode shaft element body 52A and the second electrode shaft element body 52B, A melting step of melting and degenerating according to the size.

  Thereby, one electrode assembly 44 (one metal shaft body 52) is inserted into the glass tube 42, the side tube portions 48 and 50 are sealed, and after the sealing, the metal shaft body 52 is cut. Therefore, it is difficult for an axial misalignment to occur between the completed electrodes. Moreover, since the tip portions of the first electrode shaft element body 52A and the second electrode shaft element body 52B are melted after cutting, the tip portions of both electrodes can be processed into substantially the same shape. It becomes.

Furthermore, since the distance between the electrodes is set in accordance with the volume of the main pipe portion 46 (discharge chamber 14), it is possible to suppress the luminance unevenness between manufactured lamps.
FIG. 10 is a diagram showing a schematic configuration of a lamp unit 200 including the lamp 10 manufactured as described above as a light source. The lamp unit 200 is used as a light source for a liquid crystal projector.

  As shown in FIG. 10, the lamp unit 200 has a concave reflecting mirror 212, and the lamp 10 has an interelectrode center between the first electrode 16 and the second electrode 18 of the concave reflecting mirror 212. It is integrally attached to the concave reflecting mirror 212 so as to come to the focal position. Specifically, the base 214 attached to one end of the lamp 10 is inserted into the mounting hole 218 provided at the center of the reflecting surface 216 of the concave reflecting mirror 212 and positioned, and the base 214 is positioned inside the mounting hole 218. Insulating cement 220 is fixed. The first external lead wire 36 is electrically connected to a power supply line 222 introduced through a through hole (not shown) provided in the concave reflecting mirror 212. The second lead wire 38 (not shown in FIG. 10) is electrically connected to the base 214.

As described above, the present invention has been described based on the embodiment. However, the present invention is not limited to the above-described form, and for example, the following form may be possible.
(1) In the above embodiment, the adjustment of the melting amount (degeneration amount) in the case of melting by laser irradiation is performed according to the laser irradiation time. You may perform by the irradiation position with respect to a body. Or you may change by changing these two or more.
(2) In the above embodiment, the amount of melting (degeneration amount) in the case of melting by electric discharge is adjusted by the feed power. However, the present invention is not limited to this, and the amount of current may be changed with a constant voltage. On the contrary, the voltage may be changed with the amount of current kept constant. Alternatively, it may be adjusted according to the discharge time.
(3) In the above embodiment, the melting step is performed by either laser beam irradiation or discharge. However, the present invention is not limited to this, and both may be used in combination.

For example, the tip portions of the electrode shaft base bodies 52A and 52B (see FIG. 8B) are irradiated with a laser beam, and the electrode shaft base bodies 52A and 52B (in some cases) are less than the final required amount. The coils 54 and 56 are also melted [preliminary melting step], and then, as described with reference to FIG. 9, the final required amount is melted by discharge [main melting step].
It is desirable that the cutting width in the cutting process is as narrow as possible. However, if it is too narrow, there may occur a situation in which the slightly generated melt in the cutting process becomes granular and gets caught in the gap (between the cut surfaces). The body itself is completely cut off.) In particular, when laser cutting is performed in an airtight space where the assist gas cannot be used as in the present embodiment, the above situation is likely to occur. Even if power is supplied in such a state, the current flows through the granular melt, and there are cases where good discharge cannot be performed. Therefore, first, the electrode shaft element bodies 52A and 52B are slightly degenerated by the preliminary melting described above to completely separate the tips from each other, and the main melting step by the subsequent discharge is executed.
(4) In (3), both electrode shaft bodies 52A and 52B are pre-melted in the pre-melting step. However, after only one of them is pre-melted, the process is shifted to the main melting step by discharge. Also good. By doing so, it is possible to shorten the time for alignment and the like for irradiating the laser beam, and the overall manufacturing time of the high-pressure mercury lamp can be shortened.
(5) The present invention is not limited to the above-described method for manufacturing a high-pressure mercury lamp, but can be applied to other high-pressure discharge lamps such as a metal halide lamp and a high-pressure sodium lamp.
(6) Moreover, this invention is applicable not only to what has a coil in an electrode but the manufacturing method of the high pressure discharge lamp by which an electrode is comprised only with a shaft.
(7) In the above embodiment, the longitudinal section of the main section 46 is imaged, and the volume size of the main section 46 is obtained from the imaging result. An imaging device (X-ray CT [Computed tomography]) may be used to image a cross section of the main section 46 (tomographic imaging) and obtain the volume size of the main section 46 from the tomographic image. That is, tomographic imaging of the main section 46 is performed a plurality of times at a predetermined interval in the X-axis direction (see FIG. 6), the area of the discharge chamber 14 in each tomographic image is obtained, and the obtained areas are totaled. The volume of the main pipe portion 46 is set.
(8) In the above embodiment, the interelectrode distance is set to any one of the three stages D1, Ds, and D2 depending on which of the three ranges divided by V1 and V2 the measurement volume Vd belongs to. It was decided to control (see Table 1 etc.). However, instead of dividing the volume range in this way and digitally setting the inter-electrode distance in several steps, it may be set in an analog manner. That is, the relationship between the volume of the main pipe portion 46 and an appropriate inter-electrode distance is determined in advance by experiments, and this is expressed in a formula so that an appropriate inter-electrode distance can be calculated if the volume is obtained. Then, using the mathematical formula, an appropriate interelectrode distance is calculated from the measured volume Vd, and the tip of the electrode is degenerated by controlling the laser beam irradiation time or the like so as to be the interelectrode distance.

  For example, it can be suitably used in a method for manufacturing a short arc type high-pressure discharge lamp.

It is a figure which shows schematic structure of the high pressure mercury lamp which is a manufacturing object. It is a figure for demonstrating an electrode assembly insertion process. It is a figure for demonstrating a main pipe part formation process. It is a figure for demonstrating a sealing process. It is a block diagram which shows schematic structure of the system which measures the magnitude | size of the volume of a main pipe part. (A) is a captured image of the main pipe part and its vicinity, (b) is a figure for demonstrating the detection method of the magnitude | size of the volume of the main pipe part 46. FIG. It is a figure for demonstrating a cutting process. It is a figure for demonstrating the melting process by irradiation of a laser beam. It is a figure for demonstrating the melting process by discharge. It is a figure which shows schematic structure of a lamp unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 High pressure mercury lamp 16 1st electrode 18 2nd electrode 42 Glass tube 46 Main pipe part 48, 50 Side pipe part 52A 1st electrode shaft element body 52B 2nd electrode axis element body 200 Lamp unit 212 Concave reflector

Claims (6)

One electrode shaft element body including a portion serving as a first electrode and a portion serving as a second electrode in a glass tube in which the first and second side tube portions are extended from both ends of the main tube portion preparation but what the first and part of the second electrode is in the inserted state so as to be located within the main tube portion, the second side tube portion and the first side tube portion is sealed A preparation process to
In the state where the both-side tube parts are sealed, a measuring step for measuring the size of the volume in the main tube part forming the discharge chamber;
A comparison step for comparing the measurement result in the measurement step with a reference volume of the main pipe part;
A cutting step of cutting the electrode body by a laser between a portion to be the first electrode and a portion to be the second electrode;
The electrode which sets the distance between the electrodes by widening the facing interval by melting the tip portion of the portion to be the first electrode and the portion to be the second electrode separated by the cutting according to the comparison result in the comparison step A distance setting process;
The manufacturing method of the high pressure discharge lamp characterized by including. In the inter-electrode distance setting step,
2. The method of manufacturing a high-pressure discharge lamp according to claim 1, wherein the distance between the electrodes is increased as the volume measured in the measuring step with respect to the reference volume is relatively large. The size of the volume to be measured in the measurement step Vx, the reference volume Vs, the first electrode and the electrode distance as a reference between the second electrode Ls, a distance between ultimately obtainable electrode If Lx,
In the inter-electrode distance setting step, according to the comparison result in the comparison step,
When Vx is larger than Vs, Lx is longer than Ls.
When Vx is approximately equal to Vs, Lx is approximately equal to Ls.
When Vx is smaller than Vs, Lx is shorter than Ls.
Method for manufacturing a high pressure discharge lamp according to claim 1 or 2, wherein the retract by melting the tip part of the portion to be the first and second electrodes. Before Ki溶 fusion in the inter-electrode setting step, characterized in that it is made by irradiating a laser beam on the tip portion of the tip portion and the portion to be the second electrode portion serving as the first electrode The manufacturing method of the high pressure discharge lamp of any one of Claims 1-3 . Before Ki溶 fusion in the inter-electrode setting step, characterized in that it is made by means of electric discharge between the tip portion of the tip portion and the portion to be the second electrode portion serving as the first electrode The manufacturing method of the high pressure discharge lamp of any one of Claims 1-3 . The high-pressure discharge lamp has a concave reflecting mirror, and the high-pressure discharge lamp manufactured by the manufacturing method according to any one of claims 1 to 5 is positioned at a focal position of the concave reflecting mirror. A lamp unit comprising a discharge lamp.

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