JP4525803B2 - Arc tube, light source device and projector - Google Patents

Description

  The present invention relates to an arc tube that discharges light between a pair of electrodes disposed inside, a light source device including the arc tube, and a projector.

  Conventionally, a light emitting part in which a pair of electrodes are arranged and a discharge space in which a light emitting substance such as mercury and a rare gas is enclosed is formed, and extends in a direction away from each other across the light emitting part, and There is known a discharge lamp including an arc tube having a pair of sealing portions each provided with an electrode lead wire connected to each electrode. In such a discharge lamp, when a voltage is applied to the electrode, a discharge occurs at a predetermined location of the electrode, and the heat generated by the discharge moves to the tip side of each electrode (the side adjacent to each other). When the tip temperature rises to a predetermined temperature range, arc discharge is started between the tips, and the luminescent material between the electrodes reacts to emit light.

  As such an electrode, a configuration including a shaft portion (core bar) and a coil wound around the shaft portion is known. In such a stepped portion of the coil of the electrode, the electric field is concentrated, so that electric discharge is likely to occur. In addition, when the electrode becomes too high in temperature, wear and deformation of the electrode become remarkable, but the heat capacity is increased by the coil, so that the electrode is held at an appropriate temperature. Further, by winding the coil around the core rod, it is possible to easily adjust the diameter of the electrode according to the wattage of the discharge lamp.

However, when the above-mentioned step portion is located on the side close to the sealing portion, the arc generated by the discharge at the step portion collides with the inner wall of the arc tube formed of quartz glass or the like. There is. In such a case, the inner wall is damaged and the light emitting part becomes clouded, or the defect of the halogen cycle, such as tungsten adhering to the electrode constituting material, blackens, resulting in the life of the discharge lamp. There is a problem of shortening. In particular, in such a discharge lamp, the inner wall surface of the light emitting portion of the arc tube is generally formed in a substantially spherical shape with the center between the electrodes as the center. When these are close to each other, the above-described problem becomes remarkable.
In order to solve such a problem, a discharge lamp is known in which a discharge starting point is positioned on the tip side of an electrode (see, for example, Patent Document 1).

  In the discharge lamp described in Patent Document 1, a winding portion in which a tungsten wire is wound in a coil shape on the tip side of the electrode, and a curved portion in which the rearmost side of the winding portion is heat-treated and melted. In the curved portion, the step between the coil and the shaft portion is small. With such a configuration, since the discharge starting point is a gap existing between the winding parts, it is possible to prevent discharge from starting at the rear end of the electrode, which is a place where the distance between the inner wall of the arc tube and the electrode is short. Can do.

JP 2006-79986 A

Here, when the discharge lamp is turned on for a long time, a sharp crystal of tungsten released from the electrode is formed on the core rod on the rear end side of the electrode, and the crystal becomes a starting point of discharge, There is a problem that the discharge starting point is not specified.
That is, when the arc collides with the inner wall of the arc tube, the silicon oxide that is a constituent material of the arc tube evaporates and separates into silicon and oxygen, and by this separation, tungsten of the electrode evaporates, and the evaporated tungsten Among them, it is considered that tungsten halide deviated from the halogen cycle is carried near the shaft (core rod) by convection, and tungsten atoms are deposited on the shaft. Here, as described above, the stepped portion protruding outward in the radial direction of the electrode is likely to be a discharge starting point in the electrode. Therefore, when the electrode is deposited and crystallized in a sharp shape, the deposited portion is discharged at the start of lighting. It becomes the starting point. For this reason, as in the above-described discharge lamp described in Patent Document 1, a curved portion is provided on the rear end side of the coil, and even if an attempt is made to specify the position of the discharge starting point in the coil portion, the discharge lamp has a long time. There is a problem that the position of the discharge starting point cannot be determined by lighting.

  An object of the present invention is to provide an arc tube, a light source device, and a projector capable of positioning a discharge starting point at a desired position.

In order to achieve the above-described object, the arc tube of the present invention is an arc tube having a light-emitting portion having a pair of electrodes disposed therein, and discharging light between the electrodes, and the pair of light-emitting portions in the light-emitting portion. covering the one electrode side of the electrode, and a reflective member for reflecting light incident to the other electrode side, the pair of electrodes includes a small diameter portion, proximate to the other electrode of the small-diameter portion provided on an end portion on the side of and a large diameter portion having a diameter larger than the small diameter portion, the large diameter portion, and a coil portion wound along an axial direction of the small diameter portion, A main body portion located on the other electrode side of the coil portion, and only the electrode on the side on which the reflection member is provided, of the pair of electrodes, from substantially the axial center of the coil portion in the coil portion. , To the end of the main body on the other electrode side Located between, and wherein the projecting portion projects radially outward from the diameter of the large diameter portion is provided.

According to the present invention, the large-diameter portion of the electrode on the side where the reflecting member is provided has a protruding portion that protrudes outward from the diameter of the large-diameter portion. According to this, when a voltage is applied to the electrode, the electric field concentrates on the protruding portion, and the protruding portion becomes a discharge starting point. As a result, even when the electrode is consumed due to long-time lighting of the arc tube and the electrode constituent material is deposited and crystallized in the small diameter portion, the discharge starting point can be positioned at the protruding portion. In addition, since the protrusion is provided on the large-diameter portion, the heat generated by the discharge at the protrusion can be conducted to the large-diameter portion. Can be done. Therefore, in addition to being able to position the discharge starting point in the protruding portion, it is possible to quickly shift to arc discharge between the electrodes on the side close to each other, and thus the life of each electrode and arc tube can be extended. .

Further, the large diameter portion, Ru includes a coil portion wound along an axial direction of the small diameter portion and a body portion located at the other electrode side of the coil portion.
Here, when the main body portion is formed integrally with the small diameter portion so as to be larger than the diameter of the small diameter portion, the coil portion is located on the side away from the other electrode in the small diameter portion. It may also be formed by being wound around the small-diameter portion from a position spaced a predetermined distance from the tip of the small-diameter portion. In this case, a range from the tip of the small diameter portion to the coil portion corresponds to the main body portion, and a region where the main body portion and the coil portion are combined corresponds to the large diameter portion. Furthermore, the main body portion may have the same diameter as that of the small-diameter portion, and it is sufficient that at least one of the main-body portion and the coil portion has a larger diameter than the small-diameter portion.
According to the present invention, the large-diameter portion includes the main body portion and the coil portion, so that the diameter of the large-diameter portion can be easily adjusted by setting the size of the main body portion and the number of turns of the coil portion. In addition, the heat capacity can be increased. Therefore, even when the main body is heated, the consumption and deformation of the electrode can be further suppressed, and the life of the electrode can be extended.

  Here, when the arc tube is extinguished, a light emitting substance such as mercury enclosed in the light emitting portion adheres to the electrode on the side that is easily cooled. At this time, in the case where a reflective member is provided so as to cover one electrode side in the light emitting portion, the reflective member in the light emitting portion is kept warm by the reflective member. The electrode on the side where the member is provided is not easily cooled, and the electrode on the side where the reflecting member is not provided is easily cooled. For this reason, a luminescent substance tends to adhere to the electrode on the side that is easily cooled, and the protrusion is buried with the luminescent substance. If the protruding portion is buried in this way, the effect of positioning the discharge starting point at the start of lighting of the arc tube will be halved. On the other hand, the luminescent material is less likely to adhere to the electrode on the side where the reflecting member is provided, and the protruding portion of the electrode is exposed. Therefore, it is effective to position the discharge start point on the protruding portion when the arc tube is turned on. Can be done automatically. Therefore, by providing the protrusion only on the electrode side where the discharge starting point can be positioned effectively, the manufacturing process of the arc tube and the manufacturing cost can be reduced compared to the case where the protrusion is provided on each electrode. Can be planned.

In this invention, it is preferable that the inner wall of the said light emission part is formed in the substantially spherical shape which has a center located between a pair of said electrodes.
Here, when the inner wall of the light emitting portion is formed in a substantially spherical shape centered on the center between the electrodes, and the protruding portion is located at a position on the side away from the other electrode in the large diameter portion, the protruding portion Since the distance between the light emitting portion and the inner wall of the light emitting portion is short, there is a possibility that an arc caused by discharge at the protruding portion collides with the inner wall of the light emitting portion and damages the inner wall. In addition, when a protrusion is provided at the position, the heat generated by the discharge at the protrusion is difficult to conduct to the tip of the electrode, and the discharge period at the protrusion becomes longer, resulting in discharge. The probability that the arc hits the light emitting part becomes higher.
On the other hand, in the present invention, the inner wall of the light emitting part is formed in a substantially spherical shape having a center located between the pair of electrodes, and from the substantially axial center of the coil part to the other electrode in the main body part. By positioning the protruding portion between the side ends, the distance between the protruding portion and the inner wall of the light emitting portion can be increased. Therefore, it is possible to suppress the arc generated by the discharge at the protruding portion from colliding with the light emitting portion.

In this invention, it is preferable that the said protrusion part is a circular arc-shaped member which has a substantially circular arc shape and is attached to the said large diameter part.
According to the present invention, since the protruding portion that protrudes outward from the large-diameter portion is an arc-shaped member, the range of the protruding portion on the outer periphery of the large-diameter portion is larger than when the protruding portion is formed by a protrusion. can do. In addition, when the arc tube is provided with a trigger line that improves the starting characteristics, a predetermined position on the side of the large-diameter portion facing the trigger line is likely to be a discharge starting point. On the other hand, in this invention, it can make it easy to make a protrusion part oppose a trigger wire by comprising a protrusion part by providing an arc-shaped member. Therefore, the discharge starting point can be reliably positioned at the protruding portion.

In the present invention, it is preferable that the arc-shaped member has at least one protrusion that protrudes radially outward of the arc-shaped member and becomes narrower toward the distal end in the protruding direction.
Here, since the electric field is more concentrated at the protrusion-shaped part with a thin tip, it tends to be a discharge starting point at the start of lighting of the arc tube. For this reason, in the present invention, since the arcuate member has at least one protrusion, the discharge starting point can be positioned at the protrusion.

In the present invention, it is preferable that the arcuate member has an opening through which the large diameter portion is inserted.
According to the present invention, the arcuate member has an opening, and the arcuate member can be reliably positioned in the large diameter part by inserting the large diameter part through the opening.

In this invention, it is preferable that the said arc-shaped member has a notch formed along the axial direction of the said arc-shaped member connected to the said opening.
According to the present invention, the arc-shaped member can be attached to the large-diameter portion so that the large-diameter portion is fitted into the opening from the cutout of the arc-shaped member. That is, even if it is not the manufacturing process of a large diameter part, an arc-shaped member can be attached to a large diameter part by retrofit. Therefore, it is possible to easily attach the arcuate member to the large diameter portion.
In addition, since the electric field tends to concentrate on the edge of such a notch when the arc tube starts lighting, the discharge starting point at the time of starting lighting can be positioned on the edge.

In this invention, it is preferable that the said protrusion part is comprised by the processus | protrusion which is provided in the said large diameter part and becomes thin as it goes to the direction spaced apart from the said large diameter part.
Here, as described above, the protruding portion where the tip end side becomes narrow tends to be a discharge starting point when starting the arc tube. For this reason, the discharge starting point can be reliably positioned at the protrusion by configuring the protrusion as a protrusion that becomes narrower toward the tip in the direction away from the large diameter portion.

In the present invention, it is preferable that the protruding portion protrudes in a direction away from the other electrode.
Here, when the protruding portion protrudes in the direction approaching the other electrode, the discharge at the protruding portion continues even when the tip of the large diameter portion is sufficiently heated, and the discharge position is the main body. The light emission center of the arc tube is not positioned at the center between the electrodes without shifting to the portion.
On the other hand, in the present invention, since the protruding portion protrudes in a direction away from the other electrode, the discharge at the protruding portion is performed only at the start of lighting of the arc tube, and the heat generated by the discharge is generated. Is transmitted to the tip of the electrode, and when the tip of the large-diameter portion is sufficiently heated, the tip can be discharged. Therefore, the light emission center of the arc tube can be positioned between the electrodes.
In particular, in an optical apparatus such as a projector, the present invention is effective because each optical component is arranged based on the emission center of the arc tube.

In this invention, it is preferable that the said protrusion part is provided in the said main-body part.
According to the present invention, by providing the main body with the protruding portion serving as a discharge starting point, the temperature of the main body can be quickly increased by the heat generated by the discharge in the protruding portion. In addition, when the light emitting portion is formed in a substantially spherical shape centering on the center between the electrodes, the distance between the protruding portion and the inner wall of the light emitting portion can be increased. It can suppress that the produced | generated arc collides with the inner wall of a light emission part. Therefore, it is possible to promptly shift to arc discharge in the main body of the electrode, improve the starting characteristics of the arc tube, and suppress the cloudiness and blackening of the light emitting portion.
Further, when such a protruding portion is configured as a separate member and the protruding portion is formed by attaching the member to the main body portion, it is easier to attach the member to the main body portion than to attach the member to the coil portion. Therefore, the manufacturing process of the electrode can be simplified.

Or in this invention, it is preferable that the said protrusion part is provided in the said coil part.
Here, the coil portion is less consumed and deformed than the main body portion even when the arc tube is lit for a long time. For this reason, in this invention, by providing a protrusion part in a coil part, the consumption and deformation | transformation of a protrusion part can be suppressed, and there exists an effect of positioning the discharge starting point to the above-mentioned protrusion part over a long period of time. Can do.

In the present invention, it is preferable that the protruding portion is formed of a material obtained by adding a starting auxiliary substance to the same material as the large diameter portion.
An example of such a large diameter material is tungsten. Moreover, as a starting auxiliary substance, the metal which is easy to discharge | release an electron by the application of a voltage is preferable, and thorium can be illustrated.
According to the present invention, since the starting auxiliary substance is added to the protrusion, discharge at the protrusion can be promoted. Therefore, the protruding portion can be more reliably defined as the discharge starting point.

In the present invention, a trigger line is provided along the outer surface of the arc tube and a voltage is applied to assist the starting of the arc tube, and the protruding portion protrudes toward the trigger line. It is preferable.
Here, as described above, the discharge generated at the time of starting the arc tube has a high probability of being generated at a portion of the large diameter portion facing the trigger line. For this reason, in this invention, since the protrusion part protrudes toward the said trigger line, it can make it easy to position the discharge starting point at the time of lighting start of an arc_tube | light_emitting_tube on the said protrusion part. Therefore, it is possible to more reliably position the discharge starting point at the protruding portion.

The light source device of the present invention includes the above-described arc tube and a reflecting mirror that reflects the light emitted from the arc tube in one direction to emit the light as a light beam.
According to the present invention, the same effects as those of the arc tube described above can be achieved. In addition, since the life of the arc tube can be extended, the trouble of frequently replacing the arc tube can be saved.

A projector according to the present invention includes the light source device described above, a light modulation device that modulates a light beam emitted from the light source device according to image information, and a projection optical device that projects the modulated light beam. To do.
According to the present invention, the same effects as those of the light source device described above can be obtained. In addition, since the life of the arc tube can be extended, it is possible to suppress a rapid decrease in the emission luminance of the arc tube due to long-time lighting, and it is possible to suppress a decrease in the luminance of the projected image.

[1. First Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
[Configuration of Projector 1]
FIG. 1 is a schematic diagram showing a schematic configuration of a projector 1 according to the present embodiment.
The projector 1 modulates a light beam emitted from a light source device 411 provided therein according to image information to form image light, and an image related to the image light is projected on a projection surface such as a screen (not shown). Enlarged projection. As shown in FIG. 1, the projector 1 includes an exterior housing 2, a projection lens 3, an optical unit 4, and the like.
In addition to these, the projector 1 includes a cooling unit 91 configured by a cooling fan or the like that cools the interior of the projector 1, a power supply unit 92 that supplies power to each component in the projector 1, and the entire projector 1. The control unit 93 and the like for controlling are provided, and these are arranged in the exterior housing 2.
Among these, the power supply unit 92 converts the commercial alternating current supplied from the outside of the projector 1 into a direct current, and raises or lowers the voltage to a voltage corresponding to each component inside the projector 1, and then supplies power to each component.

[Configuration of exterior casing 2 and projection lens 3]
The exterior housing 2 is formed in a substantially rectangular parallelepiped shape in which the projection lens 3, the optical unit 4, and the like are housed and arranged inside. Although this exterior housing | casing 2 was formed with the synthetic resin in this embodiment, you may form not only this but other materials, such as a metal, for example.
The projection lens 3 is a projection optical device that forms an image of the image light formed by the optical unit 4 on a projection surface such as a screen (not shown) and enlarges and projects an image related to the image light. The projection lens 3 is configured as a combined lens in which a plurality of lenses are housed in a cylindrical lens barrel.

[Configuration of Optical Unit 4]
The optical unit 4 is a unit that optically processes a light beam emitted from a light source to form image light corresponding to image information under the control of the control unit 93 described above. As shown in FIG. 1, the optical unit 4 extends along the back surface of the exterior housing 2 and has a substantially L shape in plan view that extends along the side surface of the exterior housing 2. .
The optical unit 4 houses and arranges an illumination optical device 41, a color separation optical device 42, a relay optical device 43, an electro-optical device 44, and these optical components 41 to 44, and a projection lens 3 in a predetermined manner. And an optical component casing 45 which is supported and fixed at the position.

  The illumination optical device 41 illuminates an image forming area of a later-described liquid crystal panel 442 constituting the electro-optical device 44 substantially uniformly. The illumination optical device 41 includes a light source device 411, a first lens array 412, a second lens array 413, a polarization conversion element 414, and a superimposing lens 415.

  The light source device 411 is reflected by the discharge lamp 5 that emits a radial light beam, the main reflecting mirror 6 that reflects the emitted light emitted from the discharge lamp 5 and converges it at a predetermined position, and the main reflecting mirror 6. The collimating concave lens 7 that collimates the converged light beam with respect to the illumination optical axis A and a housing (not shown) that accommodates the collimating concave lens 7 are provided. The configurations of the discharge lamp 5 and the main reflecting mirror 6 will be described in detail later.

The first lens array 412 has a configuration in which a plurality of small lenses are arranged in a matrix in a plane substantially orthogonal to the illumination optical axis A. These small lenses have a substantially rectangular outline when viewed from the direction of the illumination optical axis A. Each of these small lenses divides the light beam emitted from the light source device 411 into a plurality of partial light beams.
The second lens array 413 has a configuration similar to that of the first lens array 412, and has a configuration in which small lenses corresponding to the small lenses of the first lens array 412 are arranged in a matrix. The second lens array 413 has a function of forming an image of each small lens of the first lens array 412 together with the superimposing lens 415 on an image forming area of a liquid crystal panel 442 described later of the electro-optical device 44. .

The polarization conversion element 414 is disposed between the second lens array 413 and the superimposing lens 415, and converts light from the second lens array 413 into substantially one type of linearly polarized light.
Specifically, each partial light converted into approximately one type of linearly polarized light by the polarization conversion element 414 is finally superimposed on an image forming area of a liquid crystal panel 442, which will be described later, by a superimposing lens 415. In a projector using a liquid crystal panel of a type that modulates polarized light, only one type of polarized light can be used, and therefore approximately half of the light from the light source device 411 that emits randomly polarized light cannot be used. For this reason, by using the polarization conversion element 414, the light emitted from the light source device 411 is converted into substantially one type of linearly polarized light, and the light use efficiency in the electro-optical device 44 is increased.

The color separation optical device 42 includes two dichroic mirrors 421 and 422 and a reflection mirror 423, and a plurality of partial light beams emitted from the illumination optical device 41 by the dichroic mirrors 421 and 422 are converted into red (R) and green ( G) and blue (B) are separated into three color lights.
The relay optical device 43 includes an incident side lens 431, a relay lens 433, and reflection mirrors 432 and 434, and has a function of guiding the red light separated by the color separation optical device 42 to the liquid crystal panel 442R for red light. .

  At this time, the dichroic mirror 421 of the color separation optical device 42 transmits the red light component and the green light component of the light beam emitted from the illumination optical device 41 and reflects the blue light component. The blue light reflected by the dichroic mirror 421 is reflected by the reflection mirror 423, passes through the field lens 441, and reaches the blue light liquid crystal panel 442B. The field lens 441 converts each partial light beam emitted from the second lens array 413 into a light beam parallel to the central axis (principal ray). The same applies to the field lens 441 provided on the light incident side of the other liquid crystal panels 442G and 442R for green light and red light.

  Of the red light and green light transmitted through the dichroic mirror 421, the green light is reflected by the dichroic mirror 422, passes through the field lens 441, and reaches the liquid crystal panel 442G for green light. On the other hand, the red light passes through the dichroic mirror 422, passes through the relay optical device 43, and further passes through the field lens 441 to reach the liquid crystal panel 442R for red light. Note that the relay optical device 43 is used for red light because the optical path length of the red light is longer than the optical path lengths of the other color lights, thereby preventing a decrease in light use efficiency due to light diffusion or the like. It is to do. That is, this is to transmit the partial light beam incident on the incident side lens 431 to the field lens 441 as it is. The relay optical device 43 is configured to pass red light out of the three color lights, but is not limited thereto, and may be configured to pass blue light, for example.

The electro-optical device 44 modulates the three color lights emitted from the color separation optical device 42 according to image information, and combines the modulated color lights to form an optical image (color image).
As shown in FIG. 1, the electro-optical device 44 includes the above-described field lens 441, a liquid crystal panel 442 as a light modulation device (442R for a red light liquid crystal panel, 442G for a green light liquid crystal panel, and 442G; A liquid crystal panel for blue light is referred to as 442B), three incident-side polarizing plates 443 respectively disposed on the light incident side of each liquid crystal panel 442, and 3 disposed on the light emission side of each liquid crystal panel 442. And two crossing dichroic prisms 446 as a color synthesizing optical device, and three crossing dichroic prisms 446 disposed on the light beam emission side of the three viewing angle compensation plates 444, respectively. ing.

The incident-side polarizing plate 443 receives light of each color whose polarization direction is aligned in approximately one direction by the polarization conversion element 414. The incident-side polarizing plate 443 is aligned by the polarization conversion element 414 in the incident light flux. Only polarized light having substantially the same direction as that of the polarized light beam is transmitted, and other light beams are absorbed. Such an incident-side polarizing plate 443 has a configuration in which a polarizing layer is attached to a light-transmitting substrate such as sapphire glass or crystal.
A liquid crystal panel 442 as a light modulation device has a configuration in which liquid crystal, which is an electro-optical material, is hermetically sealed between a pair of transparent glass substrates, although detailed illustration is omitted. In the liquid crystal panel 442, the alignment state of the liquid crystal is controlled according to the drive signal that is the image information input from the control unit, and the polarization direction of the polarized light beam emitted from the incident-side polarizing plate 443 is modulated. As a result, image light is formed.

The viewing angle compensator 444 is configured to detect normal light and extraordinary light due to birefringence generated in the liquid crystal panel 442 when the light flux is obliquely incident on the liquid crystal panel 442 (when the light is incident on the liquid crystal panel 442 with an inclination). Compensate for the phase difference that occurs during
The exit-side polarizing plate 445 transmits only the light beam having a polarization direction perpendicular to the transmission axis of the light beam in the incident-side polarizing plate 443 out of the light beam emitted from the liquid crystal panel 442 and passing through the viewing angle compensation plate 444, and other light beams. It absorbs. Such an exit-side polarizing plate 445 can have the same configuration as the above-described incident-side polarizing plate 443.

  The cross dichroic prism 446 forms an optical image (color image) by combining the modulated light modulated for each color light emitted from the emission side polarizing plate 445. The cross dichroic prism 446 has a square shape in plan view in which four right angle prisms are bonded together, and two dielectric multilayer layers are formed at the interface where the right angle prisms are bonded together. These dielectric multilayer layers transmit the color light through the exit side polarizing plate 445 disposed on the side facing the projection lens 3 (G color light side), and the remaining two exit side polarizing plates 445 (R color light side and B color side). Reflects colored light via the colored light side). In this manner, the color lights modulated by the incident-side polarizing plates 443, the liquid crystal panels 442, the viewing angle compensation plates 444, and the emission-side polarizing plates 445 are combined to form a color image.

[Configuration of Discharge Lamp 5]
FIG. 2 is a longitudinal sectional view showing the discharge lamp 5 and the main reflecting mirror 6 of the light source device 411.
As shown in FIG. 2, the discharge lamp 5 is a light source that emits light, and includes an arc tube 51A formed of quartz glass, a sub-reflecting mirror 52 and a trigger line 53 attached to the arc tube 51A. ing. In addition, as such a discharge lamp 5, various discharge light source lamps that emit light with high luminance can be employed, and for example, a metal halide lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, and the like can be employed.

[Configuration of arc tube 51A]
The arc tube 51A is formed in the central portion of the arc tube 51A, and extends in a direction that is spaced from each other from both ends of the light emitter 511 with the light emitter 511 bulging in a substantially spherical shape. And a pair of sealing portions 512 and 513 (the left sealing portion in FIG. 2 is 512 and the right sealing portion is 513).
Among these, inside the light emitting part 511, a pair of electrodes 8A (the electrode on the sealing part 512 side is 8AL and the electrode on the sealing part 513 side is 8AR) are arranged, and between the pair of electrodes 8A, A discharge space S is formed in which a luminescent material containing mercury, a rare gas, and a small amount of halogen is enclosed.

  Inside the pair of sealing portions 512 and 513, metal foils 5121 and 5131 made of molybdenum that are electrically connected to the electrodes 8AL and 8AR in the light emitting portion 511 are inserted, respectively. An end portion on the opposite side to the light emitting portion 511 in 513 is sealed with a glass material or the like. These metal foils 5121 and 5131 are further connected to electrode lead lines 514 and 515, respectively, and the electrode lead lines 514 and 515 extend to the outside of the arc tube 51A. When a voltage is applied to the electrode lead lines 514 and 515 by a lighting control device that controls the lighting of the discharge lamp 5, a potential difference is generated between the electrodes 8AL and 8AR through the metal foils 5121 and 5131. Discharge occurs, an arc image D is formed, and the inside of the light emitting unit 511 emits light.

[Configuration of main reflector 6]
Here, the main reflecting mirror 6 will be described.
The main reflecting mirror 6 corresponds to the reflecting mirror of the present invention, and is an integrally molded product made of glass that reflects incident light and converges it to the second focal point on the illumination optical axis A. The main reflecting mirror 6 is fixed with an adhesive B to one sealing portion 512 of the discharge lamp 5 (sealing portion 512 located on the proximal end side in the light emission direction of the light source device 411). Such a main reflecting mirror 6 is formed with a substantially cylindrical neck 61 through which the sealing portion 512 is inserted, and a concave curved reflector 62 extending from the neck 61.
Among these, a reflection surface 621 on which a metal thin film is deposited is formed on the surface of the rotation curve shape on the side facing the light emitting portion 511 in the reflection portion 62. The reflecting surface 621 is formed as a cold mirror that reflects visible light and transmits infrared rays and ultraviolet rays.

The neck portion 61 is formed with an opening 611 having a substantially circular shape in plan view through which the sealing portion 512 is inserted, and the adhesive B is injected into the opening 611 in a state where the sealing portion 512 is inserted. Thereby, the sealing portion 512 and the main reflecting mirror 6 are bonded and fixed. At this time, the position of the discharge lamp 5 and the main reflecting mirror 6 is the center of the arc image D (the arc image D generated by the arc discharge between the main body portions 8A21, which will be described later) of the electrode 8A. The position C is set to be near the first focal point of the reflecting surface 621 of the main reflecting mirror 6.
In the present embodiment, the main reflecting mirror 6 is composed of an ellipsoidal reflector having a rotational ellipsoid, but may be composed of a parabolic reflector having a rotational paraboloid. In this case, the collimating concave lens 7 is omitted. Further, the main reflecting mirror 6 may be constituted by a free-form curved reflector.

[Configuration of Sub-Reflecting Mirror 52]
The sub-reflecting mirror 52 corresponds to the reflecting member of the present invention, and is made of glass that is attached to the sealing portion 513 (sealing portion 513 opposite to the side where the main reflecting mirror 6 is attached) of the arc tube 51A. It is a molded product and is formed of the same material as that of the arc tube 51A. The sub-reflecting mirror 52 includes a substantially cylindrical neck portion 521 having an opening 5211 through which the sealing portion 513 is inserted, and a reflecting portion 522 extending from the neck portion 521.

  Among these, the reflection part 522 is arrange | positioned so that the sealing part 513 side (tip side of the light emission direction of the light source device 411) in the light emission part 511 may be covered when the sub-reflection mirror 52 is attached to the sealing part 513. The light emitting portion 511 is formed in a substantially bowl shape so as to follow the outer shape. A reflection surface 5221 is formed on a surface of the reflection portion 522 that faces the light emitting portion 511. The reflection surface 5221 is formed as a cold mirror that reflects visible light and transmits infrared rays and ultraviolet rays. Yes.

  By attaching such a sub-reflecting mirror 52 to the arc tube 51A, light emitted from the light emitting unit 511 to the side opposite to the main reflecting mirror 6 side is reflected by the reflecting surface 5221. Then, the light enters the reflecting surface 621 of the main reflecting mirror 6. For this reason, the light is reflected by the reflection surface 621 and focused on the second focal point, similarly to the light directly incident on the reflection surface 621 from the light emitting unit 511. Thereby, it is possible to suppress the generation of light that is directly emitted from the light emitting unit 511 to the front end side in the light beam emission direction of the light source device 411 and that does not enter the first lens array 412 that is positioned downstream of the light source device 411. .

[Configuration of trigger wire 53]
The trigger wire 53 is a starting auxiliary line for improving the lighting performance of the arc tube 51A, one end is wound around the sealing portion 512 in a coil shape, and the center is the light emitting portion 511, the sub-reflecting mirror 52, and the sealing portion. The other end is arranged along the line 513 and the other end is connected to the electrode lead line 515 through the connection portion 516. One end of a lead wire 517 extending to the outside of the main reflecting mirror 6 is connected to the connecting portion 516 through an insertion hole 622 formed in the vicinity of the edge of the reflecting portion 62 of the main reflecting mirror 6. The other end of the lead wire 517 is connected to a terminal 54 for applying a voltage to the electrode lead wire 515 and the trigger wire 53.
By providing such a trigger line 53 and applying a high voltage pulse voltage to the trigger line 53, the lighting performance of the discharge lamp 5 can be improved.

[Configuration of electrode 8A]
FIG. 3 is a side view showing the electrode 8AR.
As described above, the pair of electrodes 8A includes the electrode 8AL disposed on the sealing portion 512 side (the side where the sub-reflecting mirror 52 is not provided in the light emitting portion 511) and the sealing portion 513 side (the light emitting portion 511). The electrode 8AR is arranged on the side where the sub-reflecting mirror 52 is provided.
Among these, as shown in FIG. 3, the electrode 8AR includes a small-diameter portion 8A1 whose rear end side (side away from the electrode 8AL) is connected to the metal foil 5131 and a distal end side (electrode 8AL) of the small-diameter portion 8A1. And a large diameter portion 8A2 provided on the side close to the surface.
Of these, the small diameter portion 8A1 is a core rod formed of tungsten.

  The large-diameter portion 8A2 is provided on the distal end side of the small-diameter portion 8A1 so as to be connected to the main body portion 8A21 having a substantially spherical shape formed integrally with the small-diameter portion 8A1 and the rear end side of the main-body portion 8A21. Coil portion 8A22. That is, the large-diameter portion 8A2 includes a coil portion 8A22 wound along the axial direction of the small-diameter portion 8A1, and a main body portion 8A21 located on the electrode 8AL side with respect to the coil portion 8A22.

  The diameter of the main body 8A21 is set to be substantially the same as the diameter of the coil 8A22. A bulging portion 8A211 bulging from the outer surface of the main body portion 8A21 is formed at the approximate center of the surface of the main body portion 8A21 on the side close to the electrode 8AL. When discharge is performed between the bulging portion 8A211 and the bulging portion 8A211 of the electrode 8AL with the rated power, the lighting of the arc tube 51A becomes a steady state.

The coil portion 8A22 is formed as a double layer coil having an inner layer and an outer layer. Specifically, in the coil portion 8A22, the inner layer 8A221 is formed by winding a tungsten wire a predetermined number of times (six turns in this embodiment) from the front end side to the rear end side in the small diameter portion 8A1. The outer layer 8A222 is formed by winding the same number of times from the rear end side toward the front end side. Then, both ends of the wire are connected to the main body 8A21, and the heat conducted to the coil 8A22 is configured to be conducted to the main body 8A21.
In such a coil portion 8A22, an arc-shaped member 8A3 serving as a discharge starting point at the start of lighting of the discharge lamp 5 is integrally formed by heat treatment such as laser irradiation between approximately the center of the coil portion 8A22 in the axial direction and the tip side. Attached. The arcuate member 8A3 only needs to be fixed to the coil portion 8A22, and heat treatment or the like may not be performed.

FIG. 4 is a front view showing the arcuate member 8A3. That is, FIG. 4 is a view of the arcuate member 8A3 attached to the coil portion 8A22 as seen from the direction along the axial direction of the coil portion 8A22.
The arcuate member 8A3 corresponds to the protruding portion of the present invention, and as shown in FIG. 4, as shown in FIG. 4, the arcuate member 8A3 is substantially arcuate (specifically substantially C It is a member having a character shape. A substantially circular opening 8A31 in front view through which the inner layer 8A221 of the coil portion 8A22 is inserted is formed substantially at the center of the arcuate member 8A3. The diameter of the opening 8A31 is set to be approximately the same as the diameter of the inner layer 8A221.

  Further, a notch 8A32 connected to the opening 8A31 is formed on one end side (the lower side in FIG. 4) of the arcuate member 8A3 along the axial direction of the arcuate member 8A3. The dimension L of the notch 8A32 is set larger than the diameter dimension of the small diameter part 8A1 and smaller than the diameter dimension of the coil part 8A22. For this reason, when the arc-shaped member 8A3 is attached to the coil portion 8A22, one winding portion in the outer layer 8A222 of the coil portion 8A22 and the inner layer 8A221 next to the winding portion are wound. It is positioned between the winding parts of

Further, on the outer periphery of the arcuate member 8A3, a plurality of protrusions 8A33 projecting radially outward centered on the center of the arcuate member 8A3 are respectively formed radially. These protrusions 8A33 are formed so as to become thinner toward the tip. The tip portions of the protrusions 8A33 are the most distant from the center of the large diameter portion 8A2, and the tip portions protrude outward from the large diameter portion 8A2.
In the present embodiment, the electrode 8AL includes the small diameter portion 8A1 and the large diameter portion 8A2. However, unlike the electrode 8AR, the arc-shaped member 8A3 is not provided in the electrode 8AL.

[Discharge starting point at the time of starting the discharge lamp 5]
Here, the discharge starting point at the start of lighting of the discharge lamp 5 will be described.
When a voltage is applied to the pair of electrodes 8A (8AL, 8AR) of the discharge lamp 5 through the electrode lead wires 514 and 515 and the metal foils 5121 and 5131, the electrode 8A starts discharging. Here, such a discharge is likely to occur at, for example, steps and protruding portions such as the rear end portions of the inner layer 8A221 and the outer layer 8A222 in the coil portion 8A22, and particularly at the electrode 8AR, it is likely to occur at the protrusion 8A33 of the arc-shaped member 8A3. . In such an electrode 8AR, the step due to the provision of the arc-shaped member 8A3 is the largest, and the electric field is generated most strongly at the stepped portion, so that the arc-shaped member 8A3 (particularly the protrusion 8A33) is likely to be the starting point of discharge. . For this reason, in the electrode 8AR, the discharge starting point is positioned at the tip of the protrusion 8A33 of the arcuate member 8A3, and discharge starts at the start of lighting of the arc tube 51A.

The protruding portion 8A33 serving as such a discharge starting point is the protruding portion 8A33 that faces the above-described trigger line 53 among the protruding portions 8A33. Therefore, by disposing the arcuate member 8A3 so that any one of the plurality of protrusions 8A33 formed on the arcuate member 8A3 faces the trigger line 53, the discharge starting point can be surely formed on the protrusion 8A33. Can be positioned either.
When the discharge is started at the tip of the protrusion 8A33 in this manner, the heat generated by the discharge is conducted from the arc-shaped member 8A3 to the outer layer 8A222 of the coil portion 8A22 in contact with the arc-shaped member 8A3. Then, the heat is conducted to the main body 8A21 through the outer layer 8A222. When the main body portion 8A21 is sufficiently heated by such heat conduction, arc discharge occurs between the bulging portion 8A211 formed at the tip of the main body portion 8A21 and the bulging portion 8A211 of the other electrode 8AL. Be started.

According to the projector 1 of this embodiment described above, the following effects can be obtained.
(1) Of the small-diameter portion 8A1 and large-diameter portion 8A2 of the electrode 8AR of the arc tube 51A, the large-diameter portion 8A2 has an arcuate member 8A3 as a protruding portion protruding outside the large-diameter portion 8A2. Is attached. Here, at the start of lighting of the arc tube 51A, the electric field concentrates on the protruding portions of the electrodes 8AL and 8AR, and discharge starts at the protruding portions. For this reason, in the electrode 8AR, a predetermined position on the outer periphery of the arc-shaped member 8A3 attached to the large-diameter portion 8A2 is a discharge starting point. At this time, even when the electrodes 8AL and 8AR are consumed and tungsten is deposited and crystallized in the small diameter portion 8A1 in the vicinity of the sealing portions 512 and 513, abnormal discharge to the inner wall of the arc tube 51A occurs in the electrode 8AR. The outer periphery of the arcuate member 8A3 that is intentionally provided at a site where there is no concern is the position where the electric field is most strongly generated. For this reason, the arc-shaped member 8A3 is intentionally provided in the large-diameter portion 8A2, so that the discharge starting point at the electrode 8AR can be positioned on the arc-shaped member 8A3, not on the position where the tungsten is deposited and crystallized. .

  (2) Since the arc-shaped member 8A3 is attached to the large-diameter portion 8A2, heat generated by the discharge in the arc-shaped member 8A3 is easily transmitted to the large-diameter portion 8A2. According to this, since the temperature of the large-diameter portion 8A2 can be quickly increased, it is possible to promptly shift to arc discharge between the bulging portions 8A211 of the main body portion 8A21. Accordingly, the starting characteristics of the arc tube 51A can be improved and the probability of arc collision with the inner wall of the arc tube 51A can be lowered, so that the life of the electrode 8AR and thus the arc tube 51A can be extended. .

  (3) The large-diameter portion 8A2 provided at the end portion of each electrode 8A that is close to each other includes a main body portion 8A21 formed so that the small-diameter portion 8A1 on the end portion side bulges, and the main body portion 8A21. And a coil portion 8A22 wound around the rear end side (sealing portions 512 and 513 side). According to this, by adjusting the number of layers of the coil, etc., it is possible to easily adjust the large diameter portion 8A2 to have a diameter corresponding to the wattage of the arc tube 51A, and the heat capacity of the large diameter portion 8A2 is reduced. Can be bigger. Therefore, consumption and deformation of the electrodes 8AL and 8AR can be suppressed, and the life of the electrodes 8AL and 8AR can be further extended.

  (4) When the trigger wire 53 is provided in the arc tube 51A, the position facing the trigger wire 53 in the large diameter portion 8A2 is likely to be a discharge starting point. For this reason, by providing the large-diameter portion 8A2 of the electrode 8AR with the arc-shaped member 8A3 as the projecting portion, any position of the arc-shaped member 8A3 can be easily positioned at the discharge starting point. Therefore, the discharge starting point can be reliably set in the arcuate member 8A3.

  (5) The arc-shaped member 8A3 is formed with a plurality of protrusions 8A33 whose tip is tapered from the center of the arc-shaped member 8A3 toward the radially outer side along the outer periphery of the arc-shaped member 8A3. Here, in the protrusion-shaped part with a thin tip, the electric field is particularly likely to concentrate, and tends to be a discharge starting point at the time of starting the lighting of the arc tube 51A. For this reason, the arcuate member 8A3 has a plurality of the protrusions 8A33, so that the discharge starting point can be reliably positioned in the protrusion 8A33 facing the trigger line 53 in the protrusion 8A33. Therefore, the discharge starting point at the start of lighting can be more reliably positioned on the arc-shaped member 8A3.

  (6) An opening 8A31 through which the inner layer 8A221 of the coil portion 8A22 is inserted is formed in the arc-shaped member 8A3, and a notch 8A32 connected to the opening 8A31 is formed along the axial direction of the arc-shaped member 8A3. . According to this, the arcuate member 8A3 can be attached to the coil portion 8A22 so that the inner layer 8A221 of the coil portion 8A22 is fitted into the opening 8A31 via the notch 8A32. Therefore, the arcuate member 8A3 can be positioned at the large diameter portion 8A2, and the arcuate member 8A3 can be easily attached to the large diameter portion 8A2.

  (7) The arc-shaped member 8A3 is disposed at a position from the approximate center in the axial direction of the large-diameter portion 8A2 to the tip side (for example, the side close to the electrode 8AL in the electrode 8AR). The coil portion 8A22 is attached between approximately the center and the end portion on the distal end side. According to this, the distance between the inner wall of the light emitting portion 511 formed in a substantially spherical shape centered on the center between the electrodes 8AL and 8AR and the protrusion 8A33 of the arcuate member 8A3 can be increased. Therefore, it is possible to suppress the arc generated at the tip of the protrusion 8A33 from colliding with the inner wall of the light emitting unit 511. In addition, this makes it possible to maintain the internal environment of the discharge space S and to suppress the occurrence of white turbidity and blackening of the arc tube 51A, thereby extending the life of the arc tube 51A.

  (8) The arc-shaped member 8A3 is formed of a material obtained by adding a starting auxiliary material such as thorium to tungsten which is an electrode constituent material. According to this, when the voltage is applied to the electrode 8A, the arc-shaped member 8A3 can be easily discharged. Therefore, the discharge starting point can be positioned on the arcuate member 8A3 more reliably.

  (9) The light emitting substance (for example, mercury) in the light emitting section 511 adheres to the electrode that is more likely to be cooled during cooling after the arc tube 51A is turned off. At this time, the electrode 8AR on the side where the sub-reflecting mirror 52 is provided is kept cool by the sub-reflecting mirror 52, so it is difficult to cool, but the other electrode 8AL is easy to cool. For this reason, the luminescent substance adheres to the electrode 8AL. Thereafter, when a voltage is applied to each of the electrodes 8AL and 8AR to light the arc tube 51A again, the electrode 8AL is buried with the adhering luminescent material, and the arc-shaped member 8A3 is provided on the electrode 8AL. Even in such a case, there is a possibility that the discharge starting point is not properly positioned.

On the other hand, the arc-shaped member 8A3 is attached to the electrode 8AR that is located on the side where the sub-reflecting mirror 52 is provided in the light emitting unit 511 and is difficult to adhere the light emitting substance during cooling. According to this, since the arcuate member 8A3 is exposed at the electrode 8AR when the arc tube 51A is turned on, the discharge starting point can be reliably positioned on the arcuate member 8A3.
Accordingly, by providing the arc-shaped member 8A3 only on the electrode 8AR exposed when the arc tube 51A is turned on, the arc tube 51A is manufactured as compared with the case where the arc-shaped member 8A3 is provided on each of the electrodes 8AL and 8AR. It is possible to simplify the process and reduce the manufacturing cost.

[2. Second Embodiment]
Next, a projector according to a second embodiment of the invention will be described.
The projector according to the present embodiment has the same configuration as that of the projector 1 described above. However, in the projector 1, the electrode 8A includes the arc-shaped member 8A3 as a protruding portion, whereas the projector according to the present embodiment The projector of this embodiment is different from the projector 1 described above in that a substantially conical protrusion is integrally attached to the main body as the protrusion. In the following description, parts that are the same as or substantially the same as those already described are assigned the same reference numerals and description thereof is omitted.

The projector of this embodiment has the same configuration as the projector 1 described above except that the arc tube 51B is provided instead of the arc tube 51A.
The arc tube 51B includes a light emitting portion 511, a pair of sealing portions 512 and 513, and electrode lead lines 514 and 515, and a metal foil provided in the pair of sealing portions 512 and 513 inside the light emitting portion 511. A pair of electrodes 8B connected to 5121 and 5131, respectively, are arranged.

FIG. 5 is a side view showing the electrode 8BR according to the present embodiment.
The pair of electrodes 8B includes an electrode 8AL disposed on the sealing portion 512 side and an electrode 8BR disposed on the sealing portion 513 side.
Among these, as shown in FIG. 5, the electrode 8BR is formed on the small diameter portion 8A1 and the tip side of the small diameter portion 8A1 (the side close to the other electrode 8AL and away from the sealing portion 513). And a large diameter portion 8B2 having a larger diameter than the small diameter portion 8A1. Among these, the large-diameter portion 8B2 includes a main body portion 8B21 formed on the distal end side of the small-diameter portion 8A1, and a double-layer coil wound tightly around the small-diameter portion 8A1 so as to be connected to the main body portion 8B21. Part 8A22.

The main body portion 8B21 is formed so as to bulge into a substantially spherical shape having a diameter dimension substantially the same as that of the coil portion 8A22, similar to the above-described main body portion 8A21. A bulging portion 8A211 is formed at substantially the center on the front end side of the main body portion 8B21. Further, on the side of the main body 8B21 that is close to the trigger line 53, a protrusion 8B212 is formed as a protrusion of the present invention.
The protrusion 8B212 is a substantially conical member configured as a separate member from the main body portion 8B21, and the insertion hole formed on the rear end side (side adjacent to the coil portion 8A22) of the main body portion 8B21. After insertion into (not shown), the protrusion 8B212 is formed by heat fusion by laser irradiation or the like. Such a protrusion 8B212 is formed of a material obtained by adding the above-mentioned starting auxiliary substance to tungsten.

Here, the protrusion 8B212 is attached so as to protrude to the rear end side (side away from the other electrode 8AL and close to the sealing portion 513) so that the tip in the protruding direction becomes narrow. Is formed. The mounting position of the protrusion 8B212 is a position facing the trigger line 53 in the main body 8B21, and the trigger line 53 is located in the protruding direction of the protrusion 8B212.
For this reason, when a voltage is applied to the pair of electrodes 8B at the time of starting the arc tube 51B, the electrode 8BR starts a discharge at the tip portion of the protrusion 8B212, and the heat generated by the discharge is conducted to the main body portion 8B21. When the main body 8B21 is sufficiently heated, arc discharge occurs between the bulging portion 8B211 of the main body 8B21 and the bulging portion 8B211 of the other electrode 8AL.

According to the projector of the present embodiment described above, the same effects as the effects (3) and (9) described above can be obtained, and the following effects can be obtained.
(10) The main body 8B21 constituting the large-diameter portion 8B2 of the electrode 8BR is intentionally provided with a substantially conical projection 8B212 projecting outside the large-diameter portion 8B2, so that the electrode 8BR The tip of the protrusion 8B212 can be the position where the electric field is generated most strongly. According to this, it is possible to position the discharge starting point at the start of lighting of the arc tube 51B at the tip of the projection 8B212. Therefore, even when tungsten, which is an electrode constituent material, is deposited and crystallized in the small diameter portion 8A1, the discharge starting point of the electrode 8BR can be positioned at the tip of the protrusion 8B212.

  (11) By providing such a protrusion 8B212 on the main body 8B21 that is discharged when the arc tube 51B is steadily lit, the heat generated by the discharge generated at the protrusion 8B212 when the arc tube 51B is turned on, It can conduct directly to the main body 8B21. According to this, the temperature of the main body 8B21 can be quickly increased. Therefore, it is possible to quickly shift to arc discharge when the arc tube 51B is turned on, to suppress occurrence of abnormal discharge, and to suppress wear and deformation of the electrode 8B.

  (12) Since the protrusion 8B212 is provided on the main body 8B21, the distance from the inner wall of the light emitting part 511 can be increased compared to the case where the protrusion 8B212 is provided on the coil 8A22. Therefore, the collision of the arc with the inner wall can be suppressed, and the internal environment of the discharge space S can be maintained. Further, the process of forming the protrusion 8B212 can be simplified as compared with the case where the conical member related to the protrusion 8B212 is attached to the coil portion 8A22.

(13) The protruding direction of the protrusion 8B212 provided on the electrode 8BR from the main body 8B21 is set to a direction away from the other electrode 8AL. According to this, the period in which the discharge starting point is positioned on the protrusion 8B212 is a period until the main body 8B21 is sufficiently heated.
Here, when the protruding direction of the protrusion 8B212 is set in a direction close to the other electrode 8AL, even after the main body 8B21 is sufficiently heated, arc discharge occurs at the tip of the protrusion 8B212. In such a case, there is a possibility that light may not be properly incident on each of the above-described optical components whose arrangement positions are set with reference to the center between the electrodes 8B.

  On the other hand, since the projecting direction is a direction away from the other electrode 8AL, when the main body 8B21 is sufficiently heated, the electrode 8BR has a bulge formed at the tip of the main body 8B21. Arc discharge can be performed in the section 8B211. Therefore, in a steady state, the light emission center of the arc tube 51B can be positioned in the center between the electrodes 8B, and light can be reliably incident on each optical component constituting the optical unit 4.

  (14) Similar to the arc-shaped member 8A3, the protrusion 8B212 is formed of a material obtained by adding a starting auxiliary substance such as thorium to tungsten which is an electrode constituent substance. According to this, when the voltage is applied to the electrode 8A, the protrusion 8B212 can easily generate a discharge. Accordingly, the discharge starting point of the electrode 8BR can be positioned on the protrusion 8B212 more reliably.

  (15) The protruding direction of the protrusion 8B212 is set not only to be away from the other electrode 8AL as described above, but also to face the trigger line 53 disposed outside the arc tube 51B. . Here, when a voltage is applied to the pair of electrodes 8B, discharge is started at a portion of the pair of electrodes 8B facing the trigger line 53. For this reason, by providing the protrusion 8B212 so as to protrude toward the trigger line 53, the discharge starting point of the electrode 8BR at the time of starting the lighting of the arc tube 51B can be more reliably positioned on the protrusion 8B212. .

[3. Third Embodiment]
Hereinafter, a projector according to a third embodiment of the invention will be described.
The projector according to this embodiment has the same configuration as that of the projector described in the second embodiment, but in the projector according to the second embodiment, the protrusion 8B212 has a main body 8B21 in the large-diameter portion 8B2 of the electrode 8BR. In contrast, in the projector of this embodiment, the projection is provided on the coil portion. In this respect, the projector according to the present embodiment is different from the projector according to the second embodiment. In the following description, parts that are the same as or substantially the same as those already described are assigned the same reference numerals and description thereof is omitted.

The projector according to the present embodiment has the same configuration as the projector shown in the second embodiment described above except that the arc tube 51C is provided instead of the arc tube 51B.
The arc tube 51C includes a light emitting portion 511, a pair of sealing portions 512 and 513, and electrode lead lines 514 and 515. Inside the light emitting portion 511, a metal provided in the pair of sealing portions 512 and 513 is provided. A pair of electrodes 8C respectively connected to the foils 5121 and 5131 are arranged.

FIG. 6 is a side view showing an electrode 8CR according to the present embodiment.
The pair of electrodes 8C includes an electrode 8AL disposed on the sealing portion 512 side and an electrode 8CR disposed on the sealing portion 513 side.
Among these, as shown in FIG. 6, the electrode 8CR is formed on the small-diameter portion 8A1 and the tip side of the small-diameter portion 8A1 (the side close to the other electrode 8AL and away from the sealing portion 513). And a large-diameter portion 8C2 having a larger diameter than the small-diameter portion 8A1.
The large-diameter portion 8C2 includes a main body portion 8A21 and a coil portion 8C22 that is provided so as to be connected to the rear end side of the main body portion 8A21 and has an inner layer 8A221 and an outer layer 8A222. Of these, the diameter of the outer layer 8A222 is set to be substantially the same as that of the main body 8A21, and a substantially conical projection 8C223 is irradiated with the laser beam at a portion of the outer layer 8A222 facing the trigger line 53 (see FIG. 2). It is attached by thermal fusion such as.

Similar to the above-described protrusion 8B212, the protrusion 8C223 is formed of a material obtained by adding a starting auxiliary substance to tungsten. Between the substantially center of the coil portion 8C22 and the end on the distal end side (main body portion 8A21 side), the outer layer is formed. It is attached to the outer surface of 8A222.
In the protrusion 8C223, the protruding direction from the outer layer 8A222 faces the rear end side (side away from the other electrode 8AL and close to the sealing portion 513), and in the protruding direction, A trigger line 53 is located.

According to the projector of the present embodiment described above, the same effects as the effects (3), (9), (10), (11) and (13) to (15) described above can be obtained. The effect of can be produced.
(16) The coil portion 8C22 is less consumed and deformed than the main body portion 8A21 even when the arc tube 51C is lit for a long time. For this reason, when the arc tube 51C is turned on, the coil 8C22 is provided with a projection 8C223 serving as a discharge starting point for the electrode 8CR, so that even when the arc tube 51C is lit for a long time, deformation of the projection 8C223 is suppressed. Can do. Therefore, the discharge starting point can be positioned at the tip of the protrusion 8C223 over a long period of time.

[4. Fourth Embodiment]
Next, a projector according to a fourth embodiment of the invention will be described.
The projector according to the present embodiment has the same configuration as that of the projector 1 described above. However, in the projector 1, the electrode 8A is configured to include the arc-shaped member 8A3 as a protruding portion, whereas in the projector according to the present embodiment, The projector according to this embodiment is different from the projector 1 described above in that the electrode includes a ring-shaped member as a protrusion. In the following description, parts that are the same as or substantially the same as those already described are assigned the same reference numerals and description thereof is omitted.

FIG. 7 is a side view showing the electrode 8DR according to the present embodiment.
The projector of the present embodiment has the same configuration as the projector 1 described above except that the arc tube 51D is provided instead of the arc tube 51A. The arc tube 51D has the same configuration as the arc tube 51A except that the electrode 8D is provided instead of the electrode 8A. The electrode 8D includes an electrode 8AL disposed on the sealing portion 512 side and a sealing member. It is comprised from the electrode 8DR arrange | positioned at the part 513 side.
Among these, as shown in FIG. 7, the electrode 8DR includes a small-diameter portion 8A1 and a large-diameter portion 8A2, and the large-diameter portion 8A2 is provided with a ring-shaped member 8D3.

  The ring-shaped member 8D3 corresponds to the protruding portion and the arc-shaped member of the present invention. As a separate body from the electrode 8DR, the ring-shaped member 8D3 extends from the approximate center in the axial direction of the coil portion 8A22 to the main body portion 8A21. The outer edge of the large-diameter portion 8A2 is provided so as to protrude outward from the outer edge. This ring-shaped member 8D3 is formed by winding one turn of a wire formed of a material obtained by adding the above-mentioned starting auxiliary substance to tungsten.

Specifically, the ring-shaped member 8D3 is configured as a ring in which a part of the wire rods are in contact with each other along the axial direction of the ring-shaped member 8D3. The end 8D31 on the other electrode 8AL side and the end 8D32 on the sealing portion 513 side of the ring-shaped member 8D3 have a shape sheared in a direction perpendicular to the axial direction of the wire.
When the ring-shaped member 8D3 is attached to the large-diameter portion 8A2, one end of the ring-shaped member 8D3 faces the trigger line 53, and the distance from the trigger line 53 is a ring shape. It arrange | positions so that it may become the shortest in member 8D3.

Since the end portions 8D31 and 8D32 of the ring-shaped member 8D3 have a sheared shape, an electric field is likely to concentrate on the end portions 8D31 and 8D32. Further, as described above, since the electric field is particularly concentrated at the end facing the trigger line 53, the discharge starting point of the electrode 8DR can be positioned at the end when the arc tube 51D is turned on.
Here, it is preferable that the end portion of the ring-shaped member 8D3 serving as the discharge starting point is the end portion 8D32 on the sealing portion 513 side. This is to prevent arc discharge at the end from continuing even though the electrode 8DR is sufficiently heated, similar to the above-described protrusions 8B212 and 8C223.

According to the projector of the present embodiment described above, the same effects as the effects (1) to (4) and (7) to (9) that can be achieved by the projector 1 described above can be achieved. There is an effect.
(17) By setting the inner diameter of the ring-shaped member 8D3 to a dimension corresponding to the outer diameter of the large-diameter portion 8A2, the ring-shaped member 8D3 formed by winding the wire rod for one turn is replaced with the large-diameter portion 8A2 ( It can be easily attached by, for example, screwing into the coil portion 8A22). Further, in this way, by twisting the ring-shaped member 8D3 into the large-diameter portion 8A2, the ring-shaped member 8D3 can be fixed to the large-diameter portion 8A2 without performing heat treatment such as laser irradiation. The contact area between the ring-shaped member 8D3 and the coil portion 8A22 can be reduced. According to this, since the thermal resistance of the ring-shaped member 8D3 can be increased, the temperature of the ring-shaped member 8D3 can be quickly increased, and the arc discharge in the ring-shaped member 8D3 can be performed promptly. Can do.

[5. Modification of Embodiment]
The best configuration for implementing the present invention has been disclosed in the above description, but the present invention is not limited to this. That is, the description limited to the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such is included in this invention.

  In the first embodiment, as the arcuate member attached to the large-diameter portion 8A2 of each electrode 8AL, 8AR, there are a plurality of protrusions 8A33 that have an opening 8A31 and a notch 8A32 and become narrower toward the radially outer side. Although the formed arcuate member 8A3 is illustrated, the present invention is not limited to this. That is, as long as it is an arcuate member that protrudes outside the diameter dimension of the large-diameter portion 8A2 when attached to the large-diameter portion 8A2, it may have another shape.

8-10 is a figure which shows the deformation | transformation of the said embodiment, and is a figure which shows the other shape of an arc-shaped member specifically ,.
For example, as other arc-shaped members attached to the large-diameter portion 8A2, arc-shaped members 8A4 to 8A6 shown in FIGS.
As shown in FIG. 8, the arcuate member 8A4 is formed in a substantially C shape having an opening 8A31 and a notch 8A32, and is formed at one end opposite to the notch 8A32 and becomes narrower toward the tip. Part 8A43 is formed. The protrusion 8A43 is located on the radially outer side from the large diameter portion 8A2, and serves as a discharge starting point at the start of lighting of the arc tube.

  Further, as shown in FIG. 9, the arcuate member 8A5 is formed in a substantially circular flat plate shape, and a substantially circular opening 8A51 through which the inner layer 8A221 of the coil portion 8A22 is inserted is formed in the substantially center. The diameter of the arcuate member 8A5 is set to be larger than the large diameter portion 8A2. At the start of lighting of the arc tube, a portion facing the trigger line 53 on the outer periphery of the arcuate member 8A5 becomes a discharge starting point.

  Further, as shown in FIG. 10, the arcuate member 8A6 has a substantially flat C shape obtained by removing the protrusion 8A43 from the arcuate member 8A4, and includes an opening 8A31 and a notch 8A32. For this reason, when starting the lighting of the arc tube, the electric field tends to concentrate on the edge of the notch 8A32, and since the edge has an acute angle, the electric field is particularly easy to concentrate. Can be positioned. At this time, by making the notch 8A32 face the trigger line 53, the discharge starting point can be positioned more reliably at the edge.

  Therefore, even when these arcuate members 8A4 to 8A6 are attached to the large-diameter portion 8A2, when the arcuate member 8A3 is attached, an effect similar to the effect that the arc tube 51A can exhibit can be obtained. In particular, if it is attached in the range from the approximate center of the large diameter portion 8A2 to the end portion on the side close to the other electrode, the collision of the arc with the inner wall of the light emitting portion 511 can be suppressed. Note that these arc-shaped members 8A4 to 8A6 can be formed of a material obtained by adding a starting auxiliary substance to tungsten, similarly to the arc-shaped member 8A3 described above.

  In the first and fourth embodiments, the arc-shaped member 8A3 and the ring-shaped member 8D3 are attached to the electrodes 8AR and 8DR on the side where the sub-reflecting mirror 52 is provided. Similarly, in the second and third embodiments, The projections 8B212 and 8C223 are attached to the electrodes 8BR and 8CR on the side where the sub-reflecting mirror 52 is provided, but the present invention is not limited to this. That is, the arc-shaped members 8A3 to 8A6, the ring-shaped member 8D3, and the protrusions 8B212 and 8C223 may be attached to each of the pair of electrodes, or only on the electrode opposite to the side on which the sub-reflecting mirror 52 is provided. It may be attached. Further, the arc-shaped members 8A3 to 8A6, the ring-shaped member 8D3, and the protrusions 8B212 and 8C223 may be provided in combination on at least one of the electrodes.

In the first and fourth embodiments, the arc-shaped member 8A3 and the ring-shaped member 8D3 are attached to the coil portion 8A22. However, the present invention is not limited to this. For example, the structure attached to the main-body part 8A21 may be sufficient.
That is, when the arc-shaped member 8A3 and the ring-shaped member 8D3 are attached to the coil portion 8A22 as in the above-described protrusions 8B212 and 8C223, the coil portion 8A22 is less consumed and deformed than the main body portion 8A21. For a long period of time, the arc-shaped member 8A3 and the ring-shaped member 8D3 can be used as the discharge starting point. On the other hand, when the arc-shaped member 8A3 and the ring-shaped member 8D3 are provided in the main body 8A21, the conduction efficiency of the heat generated by the discharge to the main body 8A21 is improved, so the starting characteristics of the arc tube are improved. can do.

  In the first embodiment, the arcuate member 8A3 has the plurality of protrusions 8A33, but the present invention is not limited to this. For example, the number of protrusions 8A33 may be one as in the above-described arcuate member 8A4, and the protrusions may not be provided as in the above-described arcuate member 8A6. That is, the number of the protrusions may be set as appropriate. Moreover, it is good also as a structure without the notch 8A32 in arc-shaped member 8A3, 8A4 like the above-mentioned arc-shaped member 8A5.

In the second and third embodiments, the protrusions 8B212 and 8C223 as the protrusions protrude toward the rear end side (side away from the other electrode 8AL) of each electrode 8BR and 8CR. The invention is not limited to this. That is, the protruding directions of the protrusions 8B212 and 8C223 do not necessarily have to face the rear end side. Further, the protruding direction does not have to face the trigger line 53. Also, the present invention can be applied to a discharge lamp that does not have the trigger line 53.
In the second and third embodiments, one protrusion 8B212 and 8C223 is provided for each of the large diameter portions 8B2 and 8C2. However, the number of the protrusions 8B212 and 8C223 may be set as appropriate.

  In each of the embodiments described above, the large diameter portions 8A2, 8B2, and 8C2 are the rear portions of the main body portions 8A21 and 8B21 formed so that the distal end side of the small diameter portion 8A1 swells in a substantially spherical shape, and the main body portions 8A21 and 8B21. The coil portions 8A22 and 8C22 wound around the small diameter portion 8A1 are configured to be connected to the end side, but the present invention is not limited to this. For example, the coil portion may not be provided. In such a case, the dimensions of the main body may be set according to the wattage of the discharge lamp. The number of turns and the number of layers of the coil part may be set as appropriate. Furthermore, when forming the coil part, the coil part may be formed by winding a wire with a predetermined gap without winding the wire without a gap. In addition, the main body may be formed by melting the tip of the coil by heat treatment such as laser irradiation.

In each of the above embodiments, the projector 1 includes the three liquid crystal panels 442R, 442G, and 442B, but the present invention is not limited to this. That is, the present invention can also be applied to a projector using two or less or four or more liquid crystal panels.
In each of the above embodiments, the configuration in which the optical unit 4 has a substantially L shape in plan view has been described. However, the configuration is not limited thereto, and for example, a configuration having a substantially U shape in plan view may be employed. .
Further, in each of the above embodiments, the transmissive liquid crystal panel 442 having a different light beam incident surface and light beam emission surface is used, but a reflective liquid crystal panel having the same light incident surface and light emission surface is used. Also good.

  In each of the above embodiments, the projector 1 including the liquid crystal panel 442 is illustrated as the light modulation device. You may employ | adopt a light modulation apparatus. For example, the present invention can be applied to a projector using a light modulation device other than liquid crystal, such as a device using a micromirror. When such a light modulation device is used, the polarizing plates 443 and 445 on the light incident side and the light emitting side can be omitted.

  In each of the embodiments described above, the light source device 411 including the discharge lamp 5 having the arc tubes 51A, 51B, 51C, and 51D is employed in the projector 1, but the present invention is not limited to this. That is, such a light source device 411 can also be used for other illumination devices. Further, the discharge lamp 5 can be used alone.

  INDUSTRIAL APPLICABILITY The present invention can be used as an arc tube, and particularly as an arc tube used in a light source device and a projector.

1 is a schematic diagram illustrating a configuration of a projector according to a first embodiment of the invention. The longitudinal cross-sectional view which shows the discharge lamp and main reflector in the said embodiment. The side view which shows the electrode in the said embodiment. The front view which shows the circular-arc-shaped member in the said embodiment. The side view which shows the electrode which the discharge lamp of the projector which concerns on 2nd Embodiment of this invention has. The side view which shows the electrode which the discharge lamp of the projector which concerns on 3rd Embodiment of this invention has. The side view which shows the electrode which the discharge lamp of the projector which concerns on 4th Embodiment of this invention has. The front view which shows the circular-arc-shaped member which concerns on the deformation | transformation of each said embodiment. The front view which shows the circular-arc-shaped member which concerns on the deformation | transformation of each said embodiment. The front view which shows the circular-arc-shaped member which concerns on the deformation | transformation of each said embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Projector, 3 ... Projection lens (projection optical apparatus), 6 ... Main reflection mirror (reflection mirror), 51A, 51B, 51C, 51D ... Arc tube, 53 ... Trigger wire, 8A (8AL, 8AR), 8B (8BR) ), 8C (8CR), 8D (8DR) ... electrode, 411 ... light source device, 442 (442R, 442G, 442B) ... liquid crystal panel (light modulation device), 511 ... light emitting part, 8A1 ... small diameter part, 8A2, 8B2, 8C2: Large diameter portion, 8A3, 8A4, 8A5, 8A6 ... Arc-shaped member (projecting portion), 8D3 ... Ring-shaped member (projecting portion, arc-shaped member), 8A21, 8B21 ... Main body portion, 8A22, 8C22 ... Coil portion, 8A31, 8A51 ... opening, 8A33, 8A43 ... projection, 8A32 ... notch, 8B212, 8C223 ... projection (projection).

Claims (14)

A light emitting section having a light emitting portion in which a pair of electrodes are arranged, and discharges light between the electrodes,
A reflective member that covers one electrode side of the pair of electrodes in the light emitting section and reflects incident light to the other electrode side;
It said pair of electrodes is
A small diameter part,
Provided on an end portion of the side close to the other electrode of the small-diameter portion and a large diameter portion having a diameter larger than the small diameter portion,
The large diameter portion is
A coil portion wound along the axial direction of the small diameter portion;
A main body portion located on the other electrode side from the coil portion,
Of the pair of electrodes, only the electrode on the side where the reflecting member is provided is positioned between the axial center of the coil portion in the coil portion and the end on the other electrode side of the main body portion. An arc tube characterized in that a projecting portion that projects outward in the radial direction from the diameter of the large-diameter portion is provided . The arc tube of claim 1, wherein
An arc tube characterized in that an inner wall of the light emitting portion is formed in a substantially spherical shape having a center located between the pair of electrodes. The arc tube according to claim 1 or 2,
The arc tube having the substantially arc shape and the arcuate member attached to the large diameter portion. The arc tube of claim 3, wherein
The arc-shaped member has at least one protrusion that protrudes radially outward of the arc-shaped member and becomes narrower toward the distal end in the protruding direction. The arc tube according to claim 3 or claim 4,
The arc tube has an opening through which the large diameter portion is inserted. The arc tube of claim 5, wherein
The arc-shaped member has a notch connected to the opening and formed along the axial direction of the arc-shaped member. The arc tube according to claim 1 or 2,
The arc tube according to claim 1, wherein the projecting portion is constituted by a projection that becomes narrower in a direction away from the large-diameter portion. The arc tube of claim 7,
The arc tube according to claim 1, wherein the projecting portion projects in a direction away from the other electrode. The arc tube according to any one of claims 1 to 8,
The arc tube according to claim 1, wherein the protrusion is provided on the main body. The arc tube according to any one of claims 1 to 8,
The projecting portion is provided on the coil portion. The arc tube according to any one of claims 1 to 10,
The arc tube according to claim 1, wherein the protruding portion is formed of a material obtained by adding a starting auxiliary substance to the same material as the large-diameter portion. The arc tube according to any one of claims 1 to 11,
A trigger line disposed along the outer surface of the arc tube and applied with a voltage to assist in starting the arc tube;
The arc tube according to claim 1, wherein the projecting portion projects toward the trigger line. A light emitting tube according to any one of claims 1 to 12 , and a reflecting mirror that emits the light as a light beam by reflecting the light emitted from the light emitting tube in one direction. Light source device. 14. A projector comprising: the light source device according to claim 13; a light modulation device that modulates a light beam emitted from the light source device according to image information; and a projection optical device that projects the modulated light beam. .

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