JP5245608B2 - Arc tube, light source device and projector - Google Patents

Description

  The present invention relates to a light-emitting tube having a light-emitting portion in which a pair of electrodes is arranged and discharges light between the pair of electrodes, a light source device including the light-emitting 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 electrodes via the electrode lead wire, a discharge is started between the electrodes, and the luminescent substance in the discharge space reacts to emit light.

  Here, at the start of lighting of the arc tube, the discharge starting point at which discharge is started is not located at the tip of each electrode, but is exposed on the outer surface of the electrode and in a stepped portion where the electric field (electric field) is concentrated. To position. When the discharge is started at the step portion that becomes the discharge starting point, heat is generated by the discharge, and the heat is conducted from the discharge starting point at the start of lighting toward the tip of the electrode. When the tips of the electrodes reach a predetermined temperature range, arc discharge is started between the tips.

The diameter of such an electrode is set according to the wattage of the arc tube in relation to the heat capacity of the electrode. For this reason, an electrode including an electrode bar (core bar) and a coil wound around the electrode bar is known as a configuration that facilitates adjustment of the diameter and increases the heat capacity of the electrode. (For example, refer to Patent Document 1).
In the electrode described in Patent Document 1, a step portion in the outermost layer of the coil serves as a discharge starting point, and heat generated by the discharge at the discharge starting point is transferred to the tip of the electrode through the outermost layer, and the electrode A discharge is started between the tips. In such an electrode, by appropriately setting the number of turns of the coil, the diameter of the electrode can be easily adjusted, and the electrode is maintained at an appropriate temperature even when the electrode becomes too hot. Therefore, the consumption of the electrode can be reduced.

JP 2004-288394 A

However, the electrode described in Patent Document 1 has a problem that heat generated by discharge in the outermost layer of the coil is difficult to conduct to the tip.
That is, in the outermost layer of the coil, the wires are wound so as to be in contact with each other, so that the heat capacity of the outermost layer is increased. For this reason, the heat generated by the discharge in the outermost layer is transmitted to the tip of the electrode through the winding portion (part corresponding to one turn of the wire) of the wire forming the outermost layer. The temperature does not rise quickly. On the other hand, since the distance from the outermost layer of the coil to the inner wall of the arc tube is shorter than the distance from the tip of the electrode to the inner wall, if the discharge at the discharge starting point of the outermost layer continues for a long time, the discharge starting point The probability that the generated arc collides with the inner wall is increased. In such a case, there arises a problem that the life of the arc tube is shortened, for example, the arc tube becomes clouded and blackened. Further, when the transition period to the arc discharge at the electrode tip becomes long as described above, there is a problem that the lighting startability of the arc tube is not good.

  An object of the present invention is to provide an arc tube, a light source device, and a projector capable of extending the life and improving the starting characteristics.

In order to achieve the above-described object, the arc tube of the present invention is an arc tube having a light emitting portion in which a pair of electrodes are arranged and discharges light between the pair of electrodes, And at least one of them includes a shaft portion and a large-diameter portion formed on the other electrode side of the shaft portion and having a larger diameter than the shaft portion, and the large-diameter portion is the other electrode. A main body portion that is formed on the side and discharges in a steady lighting state of the arc tube, and is provided on the side of the main body portion that is separated from the other electrode, and a single wire is wound in a plurality of layers. The outermost layer in the coil portion is formed so that the wires do not contact each other along the axial direction of the coil portion, and the inner layer that is a layer close to the outermost layer is , The wire rod is in the axial direction of the coil portion Characterized in that it is formed in contact with each other along.

  According to the present invention, at the start of lighting of the arc tube, a predetermined location on the outermost layer of the coil portion constituting the large-diameter portion serves as a discharge start point, and discharge is started at the discharge start point. Here, the inner layer, which is the inner layer adjacent to the outermost layer, is formed by closely winding the wires so that the wires are in contact with each other. Therefore, the inner layer has a large heat capacity, whereas the outermost layer is formed by the wires. Are formed so as not to contact each other, the outermost layer has a small heat capacity. For this reason, the heat generated by the discharge at the discharge starting point can be easily conducted from the outermost layer of the coil portion to the main body portion located on the tip side of the electrode, and the temperature of the main body portion can be quickly increased. . Therefore, the lighting startability of the arc tube can be improved.

In addition, since the temperature of the main body can be rapidly increased as described above, the discharge period at the discharge starting point on the outermost layer of the coil can be shortened. Here, the arc of the discharge generated in the outermost layer is drawn toward the other electrode, unlike the arc generated between the tips of the electrodes facing each other. At this time, since the arc passes through a position close to the inner wall of the arc tube, the arc may collide with the inner wall. Especially when the light emitting part is formed in a substantially spherical shape centered between the electrodes, the distance between the outermost layer and the inner wall of the light emitting part is shorter than the distance between the main body part and the inner wall, The probability of collision of the arc with the inner wall is further increased. When the arc collides with the inner wall in this manner, the above-mentioned arc tube becomes clouded and blackened.
In contrast, in the present invention, since the temperature of the main body is rapidly increased, the discharge period in the outermost layer can be shortened, and the probability of arc collision with the inner wall of the arc tube can be reduced. Therefore, it is possible to suppress the occurrence of white turbidity and blackening of the arc tube, and consequently, it is possible to extend the life of the arc tube.
Further, according to the present invention, since the coil portion is formed of a single wire, the coil portion can be easily formed as compared with the case where each layer is formed of a plurality of wires.
Further, when each layer is formed of a plurality of wire rods, an end portion is generated for each wire rod, and it is necessary to fix the end portion to the shaft portion. Moreover, an electric field may concentrate on such an end portion, and the end portion may become a discharge starting point.
On the other hand, in the present invention, since the coil portion is formed of one wire, only two end portions are generated in the entire coil portion, and the fixing operation is simplified even when the respective end portions are fixed. be able to.

In the present invention, the number of windings of the wire in the outermost layer is preferably smaller than the number of windings of the wire in the inner layer.
According to the present invention, the length of the wire that forms the outermost layer is shorter than the length of the wire that forms the inner layer. For this reason, the heat generated by the discharge in the outermost layer can be more quickly conducted to the main body portion, and can be quickly transferred to the arc discharge between the main body portions. Therefore, the discharge period in the outermost layer can be further shortened.

In the present invention, the diameter of the outermost layer is preferably larger than the maximum diameter of the main body.
Here, as described above, the electric field (electric field) is concentrated on the stepped portion on the outer surface of the electrode, so that it tends to be a discharge starting point when starting the lighting of the arc tube. On the other hand, in the present invention, the outermost layer of the coil portion protrudes to the outside of the electrode from the main body portion, so that the discharge starting point can be positioned at the step portion of the outermost layer. Therefore, at the start of lighting of the arc tube, the discharge starting point can be positioned in the outermost layer of the coil portion, and the heat generated by the discharge can be quickly conducted to the main body portion.

In the present invention, the outermost layer preferably includes at least one winding portion that is one turn of the wire along the outer periphery of the inner layer.
According to the present invention, since the outermost layer includes at least one winding portion, the coil portion can have rotational symmetry. According to this, the discharge starting point can be reliably positioned at any position of the outermost layer.

  Here, the arc tube may be provided with a starting auxiliary line that is arranged along the arc tube and assists in starting the lighting of the arc tube. When such a start auxiliary line is provided, the discharge start point of the coil portion tends to be a position facing the start auxiliary line in the outermost layer, that is, a position closest to the start auxiliary line. For this reason, since the outermost layer of the coil part has at least one winding part, the position facing the start-up auxiliary line in the winding part can be set as the discharge starting point. As well as the position of the discharge starting point. Therefore, the above-described effects of improving the lighting startability of the arc tube and extending the life of the arc tube can be reliably achieved.

In this invention, it is preferable that the edge part by the side of the said main-body part of the said wire which forms the said outermost layer is connected to the said main-body part.
According to the present invention, since the end of the outermost layer on the main body side is connected to the main body, heat generated by the discharge at the discharge starting point located in the outermost layer can be easily conducted to the main body. can do. Therefore, since the temperature of the main body can be increased more quickly, the above-described effects of improving the lighting startability of the arc tube and extending the life of the arc tube can be more reliably exhibited.

As another aspect, the outermost layer and the inner layer may be formed of different wire materials.
According to the above configuration , the outermost layer and the inner layer are formed of different materials, so that the outermost layer and the inner layer of the coil portion can be formed of different materials. For example, the inner layer can be formed of a tungsten wire, and the outermost layer can be formed of a wire obtained by adding a starting auxiliary substance (for example, thorium) to tungsten. Here, when the starting auxiliary substance is added to the wire, it is easy to cause a discharge, so that the discharge starting point can be reliably positioned on the outermost layer.
Moreover, the outermost layer and the inner layer having different wire diameters can be easily formed.

In addition, a light source device of the present invention includes the above-described arc tube, and a reflecting mirror that aligns light emitted from the arc tube in one direction and emits it as a light beam.
According to the present invention, the same effects as those of the arc tube described above can be achieved. Thereby, it is possible to configure a light source device that realizes a stable light emission amount for a long period of time.

Furthermore, 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. It is characterized by.
According to the present invention, the same effects as those of the light source device described above can be obtained, and the life of the arc tube is extended, so that it is not necessary to frequently replace the light source device. Therefore, the trouble of maintenance of the projector such as replacement of the light source device can be saved.

[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 three crossing dichroic prisms 446 as a color synthesizing optical device. 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 with an inclination with respect to the normal direction of the panel surface). 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.

  Molybdenum metal foils 5121 and 5131 electrically connected to the electrodes 8AL and 8AR, respectively, are inserted inside the pair of sealing portions 512 and 513, and the light emitting portion 511 in the pair of sealing portions 512 and 513 is inserted. The end on the opposite side 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 positions of the discharge lamp 5 and the main reflecting mirror 6 are the center positions of the arc image D (the arc image D generated by the discharge between the body portions 824 described later of the electrode 8A) in the light emitting portion 511 of the discharge lamp 5. 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 is a glass molded product 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 formed of the same material. 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 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 8AL.
Hereinafter, the configuration of the electrode 8AL will be described.
As described above, the pair of electrodes 8A includes the electrode 8AL disposed on the sealing portion 512 side and the electrode 8AR disposed on the sealing portion 513 side, and the electrodes 8AL and 8AR have the same configuration. have.
Among these, as shown in FIG. 3, the electrode 8AL includes a shaft portion 81 that is a core rod whose rear end side (side away from the electrode 8AR) is connected to the metal foils 5121 and 5131, and the shaft portion 81. And a large-diameter portion 82A having a diameter larger than that of the shaft portion 81 and provided on the tip end side (side adjacent to the electrode 8AR). Of these, the shaft portion 81 is made of tungsten.

  The large-diameter portion 82A includes a coil portion 821 formed by winding a wire around the shaft portion 81 on the distal end side of the shaft portion 81, and the distal end side of the coil portion 821 and the shaft portion 81 (close to the electrode 8AR). And a main body portion 824 having a substantially spherical shape formed by melting the side) by laser irradiation or the like. That is, the large-diameter portion 82A is provided on the main body portion 824 formed on the electrode 8AR side and the rear end side (side away from the electrode 8AR) of the main body portion 824, and the wire L is wound in a plurality of layers. And a coil portion 821 formed in this manner. Among these, the diameter dimension of the main body part 824 is substantially the same as the diameter dimension of the inner layer 822 of the coil part 821.

In this embodiment, the coil portion 821 is formed as a two-layer coil having an inner layer 822 and an outer layer 823.
Specifically, the inner layer 822 is formed by winding a tungsten wire L around the shaft portion 81 a predetermined number of times (eight turns in this embodiment) from the front end side to the rear end side of the shaft portion 81. ing. That is, the inner layer 822 has seven winding portions 8221 corresponding to one winding of the wire along the outer periphery of the shaft portion 81 after the body portion 824 is formed, and the adjacent winding portions 8221 are made of the wire L. The outer surfaces are in contact with each other.

The outer layer 823 corresponds to the outermost layer of the present invention, and the diameter dimension of the outer layer 823 is set to be larger than the maximum diameter dimension of the main body portion 824. Thus, the outer layer 823 is a cross-sectional view of the large diameter portion 82A. Sometimes it protrudes outward from the main body 824. Such an outer layer 823 is formed by winding the wire L on which the inner layer 822 is formed from the rear end side of the electrode 8A toward the front end side. The outer layer 823 is formed with a number of windings equal to or less than 2/3 of the number of windings of the wire L in the inner layer 822. Specifically, the outer layer 823 is less than the number of winding portions 8221 of the inner layer 822 in this embodiment. Two winding portions 8231 are provided. The winding portions 8231 are not in contact with each other in the direction along the axial direction of the shaft portion 81. That is, in the inner layer 822, each winding part 8221 is formed densely so as to contact each other, whereas in the outer layer 823, each winding part 8231 is formed sparsely at a predetermined interval. Has been. Then, the end of the wire L forming the outer layer 823 is connected to the main body 824.
Note that the electrode 8AR on the sealing portion 513 side has the same configuration as the electrode 8AL, and thus the description thereof is omitted.

FIG. 4 is a diagram illustrating a manufacturing process of the electrode 8A.
The electrode 8AL described above is manufactured by the following steps.
Specifically, when manufacturing the electrode 8AL, as shown in the upper and middle stages of FIG. 4, the wire L is wound around the shaft part 81 constituting the electrode 8AL, and the inner layer 822 and the outer layer of the coil part 821 are wound. 823 is formed. Here, when the inner layer 822 is formed, the wire L from the front end side (the side opposite to the side connected to the metal foil) of the shaft portion 81 toward the rear end side (the side connected to the metal foil). The wire L is wound so that the outer surfaces of the two are in contact with each other. Thereby, the adjacent winding parts 8221 in the inner layer 822 are in contact with each other.

When forming the outer layer 823, the wire L having the inner layer 822 formed is wound around the inner layer 822 from the rear end side of the shaft portion 81 toward the front end side. At this time, the wire L is wound so that the outer surfaces of the wire L serving as the outer layer 823 do not contact each other along the axial direction of the coil portion 821. Thereby, the adjacent winding parts 8231 in the outer layer 823 do not contact each other.
After the coil portion 821 is formed in this way, as shown in the lower part of FIG. 4, the tip portion of the coil portion 821 and the shaft portion 81 is irradiated with laser light or the like to dissolve the tip portion, and the main body portion 824. Form. In addition, by forming the main body portion 824 in this way, both ends of the wire L forming the coil portion 821 are connected to the main body portion 824.
The electrode 8AR can also be manufactured in the same manufacturing process as 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, a discharge occurs between the electrodes 8A. Here, paying attention to one electrode 8AL, the discharge generated at the electrode 8AL at the start of lighting is generated in the outer layer 823 of the coil portion 821 because the electric field (electric field) is concentrated on the step portion in the large diameter portion 82A. More specifically, the discharge is generated at a portion facing the trigger line 53 in the outer layer 823 and closest to the trigger line 53. This part becomes a discharge starting point at which discharge is started at the start of lighting of the arc tube 51A.

  When the discharge is started at the discharge start point on the outer layer 823 in this way, the heat generated by the discharge is conducted through the outer layer 823 wound more sparsely than the inner layer 822 and reaches the main body 824. When the main body 824 is sufficiently heated by this heat conduction, arc discharge is started between the tip of the main body 824 and the main body 824 of the other electrode 8A.

According to the projector 1 of the present embodiment described above, the following effects can be obtained.
(1) The outer layer 823 of the coil portion 821 provided on the electrode 8A (8AL, 8AR) is formed sparsely so that the outer surfaces of the wire L do not contact each other. According to this, since the step where the electric field concentrates can be formed in the outer layer 823, the discharge starting point at the start of lighting of the arc tube 51A can be positioned in the outer layer 823. In addition, since the outer layer 823 is formed in this manner, the heat capacity of the outer layer 823 is reduced, so that heat generated by the discharge at the discharge starting point can be easily conducted to the main body portion 824. Accordingly, the temperature of the main body 824 can be quickly increased, so that the lighting startability of the arc tube 51A can be improved.

  (2) The temperature of the main body 824 of the electrode 8A (for example, the electrode 8AL) is quickly increased, and arc discharge between the main body 824 and the main body 824 of the other electrode 8A (for example, the electrode 8AR) You can move quickly. For this reason, the period of the discharge performed between the outer layer 823 of the coil part 821 and the other electrode 8A can be shortened, and the probability that the arc of the discharge collides with the inner wall of the light emitting part 511 is reduced. Can do. Therefore, the occurrence of white turbidity and blackening of the arc tube 51A can be suppressed, and consequently the life of the arc tube 51A can be extended.

  (3) The inner layer 822 has seven winding parts 8221, and the outer layer 823 has two winding parts 8231, whereby the length of the wire L forming the outer layer 823 is the same as that of the inner layer 822. It becomes shorter than the length dimension of the wire L to form. According to this, the heat generated by the discharge in the outer layer 823 can be more quickly conducted to the main body 824. Therefore, it is possible to promptly shift to arc discharge performed between the main body portions 824, and the discharge period in the outer layer 823 can be further shortened.

  (4) Since the diameter dimension of the outer layer 823 is larger than the maximum diameter dimension of the main body portion 824, the outer layer 823 protrudes outside the main body portion 824 when the electrode 8A is viewed in cross section. According to this, since the electric field (electric field) is strongly concentrated on the step portion of the outer layer 823, the discharge starting point can be positioned at the step portion. Accordingly, since the discharge starting point can be positioned in the outer layer 823 at the start of lighting of the arc tube 51A, the heat generated by the discharge can be conducted to the main body 824 more quickly.

  (5) The outer layer 823 of the coil portion 821 includes two winding portions 8231 so that the step portion of the winding portion 8231 located on the outer surface of the coil portion 821 is opposed to the trigger wire 53. Can do. According to this, since the discharge starting point can be positioned at the position closest to the trigger line 53 in the winding portion 8231, the discharge starting point at the start of lighting can be reliably positioned at any position on the outer layer 823. it can. Therefore, the above-mentioned effects of improving the lighting startability of the arc tube and extending the lifetime of the arc tube can be surely achieved. By providing the trigger wire 53, the lighting startability of the arc tube 51A can be improved. Further improvement can be achieved.

  (6) The end of the electrode 8 </ b> A on the outer layer 823 of the coil portion 821 is connected to the main body portion 824. According to this, the heat generated by the discharge in the outer layer 823 can be more rapidly conducted to the main body 824. Therefore, since the temperature of the main body 824 can be increased more quickly, the above-described effects of improving the lighting startability of the arc tube 51A and extending the life of the arc tube can be more reliably achieved. .

  (7) Since the coil portion 821 is formed of one wire L, the coil portion 821 can be easily formed as compared with the case where each layer (inner layer 822 and outer layer 823) is formed of a plurality of wires. Can do. Moreover, by forming in this way, only two end portions are generated in the entire coil portion 821. According to this, even when each end portion is fixed, the fixing operation can be simplified as compared with the case where the end portions of each layer are fixed.

  (8) Since the life of the arc tube 51A can be extended as described above, it is not necessary to frequently replace the light source device 411 in the projector 1. Therefore, the maintenance work of the projector 1 such as replacing the light source device 411 can be saved.

[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 electrode 8A of the arc tube 51A provided in the projector 1, the outer layer 823 of the coil portion 821 includes two winding portions 8231. On the other hand, in the projector according to the present embodiment, the projector is different from the projector 1 described above in that the end on the rear end side and the end on the front end side in the outermost layer are connected in a substantially straight line shape. To do. 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 8BL of the arc tube 51B according to the present embodiment.
The pair of electrodes 8B includes an electrode 8BL disposed on the sealing portion 512 side and an electrode (not shown) disposed on the sealing portion 513 side, and these have the same configuration.
Among these, as shown in FIG. 5, the electrode 8 </ b> BL has a shaft portion 81 and a tip end side of the shaft portion 81 (a side close to the other electrode (not shown) and a side away from the sealing portion 512). And a large diameter portion 82B having a diameter larger than that of the shaft portion 81. The large-diameter portion 82B includes a coil portion 825 and a main body portion 824 formed by melting the coil portion 825 and the distal end side of the shaft portion 81.

The coil portion 825 is formed by the wire L, and the inner layer 822 formed so that adjacent winding portions 8221 are in contact with each other on the outer surface, and the wire L forming the inner layer 822 is wound back. And an outer layer 826 as the outermost layer.
The outer layer 826 has a configuration that does not have a winding portion like the winding portion 8231 of the outer layer 823 described above. Specifically, the outer layer 826 has a configuration in which the wire L forming the inner layer 822 is linearly drawn from the rear end side toward the front end side along the outer surface of the inner layer 822. With such a configuration, the outer layer 826 has a larger diameter than the main body 824 having substantially the same diameter as the inner layer 822. Therefore, when the electrode 8BL is viewed in cross-section, the outer layer 826 protrudes outside the main body 824. To do.
Such an electrode 8B is disposed in the discharge space S formed in the light emitting portion 511 so that the outer layer 826 faces the trigger line 53 described above.

According to the projector of the present embodiment described above, the same effects as the above (1) to (4) and (6) to (8) can be obtained, and the following effects can be obtained.
(9) The outer layer 826 of the coil portion 825 constituting the pair of electrodes 8B is formed by the wire L arranged linearly along the inner layer 822, and the distal end portion of the outer layer 826 is connected to the main body portion 824. Yes. According to this, since it is not necessary to provide a winding part like the above-mentioned outer layer 823 of the coil part 821, the coil part 825 can be formed easily. In addition, since the rear end portion and the front end portion of the outer layer 826 are connected in a straight line as described above, the length of the wire L in the outer layer 826 can be shortened compared to the case where the winding portion is provided. . According to this, the heat generated by the discharge in the outer layer 826 can be quickly conducted by the main body 824. Therefore, the lighting startability of the arc tube 51B can be further improved, and the lifetime of the arc tube 51B can be extended.

[3. Third Embodiment]
Next, a projector according to a third 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 electrode 8A of the arc tube 51A provided in the projector 1, the inner layer 822 and the outer layer 823 of the coil portion 821 each have the same wire diameter. Whereas in the projector according to the present embodiment, the coil portion provided on the electrode of the arc tube is different from the projector described above in that the wire diameter of the wire material forming the inner layer and the outer layer is different. This is different from the projector 1. 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 51C is provided instead of the arc tube 51A.
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, and a metal foil provided in the pair of sealing portions 512 and 513 inside the light emitting portion 511. A pair of electrodes 8C connected to 5121 and 5131 are arranged.

FIG. 6 is a side view showing the electrode 8CL of the arc tube 51C according to the present embodiment.
The pair of electrodes 8C includes an electrode 8CL disposed on the sealing portion 512 side and an electrode (not shown) disposed on the sealing portion 513 side, and each has the same configuration.
Among these, as shown in FIG. 6, the electrode 8CL includes a shaft portion 81 and a large-diameter portion 82 </ b> C that is formed on the distal end side of the shaft portion 81 and has a diameter larger than that of the shaft portion 81. ing. The large diameter portion 82C includes a coil portion 827 and a main body portion 824 formed by heat-sealing the coil portion 827 and the distal end side of the shaft portion 81.

  Among these, the coil portion 827 is formed by the wire L1 and is formed by the inner layer 822 formed such that adjacent winding portions 8221 are in contact with each other on the outer surface, and the wire L2 having a smaller wire diameter than the wire L1. And an outer layer 828 wound from the rear end side toward the front end side along the outer surface of the inner layer 822. Among these, the tip of the wire L1 forming the inner layer 822 is melted and connected to the main body 824 when the main body 824 is formed, and the rear end is heat-sealed to the shaft 81. The diameter dimension of the inner layer 822 is substantially the same as the diameter dimension of the main body portion 824.

The outer layer 828 as the outermost layer has two winding portions 8281 that do not contact with each other on the outer surface of the wire L2. Further, the rear end of the wire L2 forming the outer layer 828 is heat-sealed to the shaft portion 81 or the inner layer 822, and the end portion on the front end side is connected to the main body portion 824.
Here, the wire L1 forming the inner layer 822 is formed of tungsten, but the wire L2 forming the outer layer 828 is formed of a material obtained by adding thorium, which is a starting auxiliary substance, to tungsten. For this reason, since the discharge characteristics in the outer layer 828 are improved, the portion of the outer layer 828 that faces the trigger line 53 and is closest to the trigger line 53 becomes a discharge starting point at the start of lighting of the arc tube 51C. The discharge is surely started at the site.

According to the projector of the present embodiment described above, the following effects can be obtained in addition to the same effects as the above-described (1) to (4) and (6).
(10) The wire diameter of the wire L2 forming the outer layer 828 of the coil portion 827 is smaller than the wire diameter of the wire L1 forming the inner layer 822. According to this, the heat capacity of the outer layer 828 can be reduced, and the temperature rise in the vicinity of the discharge starting point located in the outer layer 828 can be accelerated when the lighting tube 51C is turned on.
Further, since the wire diameter of the wire L1 forming the inner layer 822 is larger than the wire diameter of the wire L2, the heat capacity of the inner layer 822 can be increased. Therefore, consumption and deformation of the electrode 8C can be suppressed, and the life of the arc tube 51C can be further extended.

  (11) By forming the inner layer 822 and the outer layer 828 with different wires L1 and L2, the inner layer 822 and the outer layer 828 can be formed with different materials. That is, in this embodiment, the inner layer 822 can be formed of the wire L1 formed of tungsten, and the outer layer 828 can be formed of the wire L2 formed of a material obtained by adding a starting auxiliary substance to tungsten. . According to this, since the starting aid substance is included in the outer layer 828, a discharge can be easily generated in the outer layer 828, and the discharge starting point can be reliably positioned on the outer layer 828. In addition, since the inner layer 822 and the outer layer 828 are formed of different wire materials L1 and L2, the inner layer 822 and the outer layer 828 having different wire diameters can be easily formed.

[4. Fourth Embodiment]
Next, a projector according to a fourth embodiment of the invention will be described.
The projector according to this embodiment has the same configuration as that of the projector 1 described above. However, in the electrode 8A of the arc tube 51A provided in the projector 1, the coil portion 821 has two layers, an inner layer 822 and an outer layer 823. On the other hand, in the projector according to the present embodiment, the projector is different from the projector 1 described above in that the coil portion provided on the electrode of the arc tube has a configuration including three layers. 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 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 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 8D connected to 5121 and 5131, respectively, are arranged.

FIG. 7 is a side view showing the electrode 8DL of the arc tube 51D according to the present embodiment.
The pair of electrodes 8D includes an electrode 8DL disposed on the sealing portion 512 side and an electrode (not shown) disposed on the sealing portion 513 side, and these have the same configuration.
Among these, as shown in FIG. 7, the electrode 8DL includes a shaft portion 81 and a large-diameter portion 82D that is formed on the distal end side of the shaft portion 81 and has a larger diameter than the shaft portion 81. ing. The large-diameter portion 82D includes a coil portion 829 and a main body portion 824 formed by heat-sealing the coil portion 827 and the distal end side of the shaft portion 81.

  Of these, the coil portion 829 is configured as a coil having three layers. More specifically, the coil portion 829 includes a first layer (not shown) tightly wound around the shaft portion 81 from the rear end side (side connected to the metal foil) of the shaft portion 81 toward the front end side. A second layer 8292 as an inner layer tightly wound from the front end side toward the rear end side on the outer side of the first layer, and an outer side of the second layer 8292 from the rear end side toward the front end side. And a third layer 8293 as an outermost layer wound sparsely.

Specifically, the first layer and the second layer 8292 have a plurality of winding portions 82922 (the winding portion of the first layer is not shown), and are adjacent to each other in the first layer and the second layer 8292. The winding portions 82921 are formed densely so as to contact each other.
On the other hand, the third layer 8293 has two winding portions 82931 and is formed so that adjacent winding portions 82931 in the third layer 8293 do not contact each other. The diameter of the third layer 8293 is set to be larger than the maximum diameter of the main body portion 824 having substantially the same diameter as the second layer 8292. Therefore, when the electrode 8D is viewed in cross section, the third layer 8293 8293 protrudes outside the main body 824.

According to the projector of the present embodiment described above, the same effects as the above (1) to (8) can be obtained, and the following effects can be obtained.
(12) The coil portion 829 has a three-layer structure including a first layer and a second layer 8292 inside the third layer 8293. According to this, the heat capacity of the inner layer of the coil portion 829 can be increased. Therefore, even when the main body portion 824 is abnormally heated, the heat of the main body portion 824 can be held in the inner layer, so that the main body portion 824 can be kept at an appropriate temperature, and hence the electrode 8D is consumed and deformed. Can be suppressed.

[5. Fifth Embodiment]
Next, a projector according to a fifth 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 electrode 8A of the arc tube 51A provided in the projector 1, the outer layer 823 has a wire L from the rear end side to the front end side of the electrode 8A. In the projector according to the present embodiment, the outer layer of the coil portion provided in the electrode of the arc tube is formed so as to protrude to the tip side. The projector is different from the projector 1 described above. 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. 8 is a side view showing the electrode 8EL of the arc tube 51E according to the present embodiment.
The projector of this embodiment has the same configuration as the projector 1 described above except that the arc tube 51E is provided instead of the arc tube 51A. The arc tube 51E has the same configuration as the arc tube 51A except that the arc tube 51E includes a pair of electrodes 8E instead of the pair of electrodes 8A.
The pair of electrodes 8E is composed of an electrode 8EL disposed on the sealing portion 512 side and an electrode (not shown) disposed on the sealing portion 513 side, and these have the same configuration.
Among these, as shown in FIG. 8, the electrode 8 </ b> EL is configured to include a shaft portion 81 and a large-diameter portion 82 </ b> E that is formed on the distal end side of the shaft portion 81 and has a larger diameter than the shaft portion 81. ing. Among these, the large-diameter portion 82E includes a coil portion 830 and a main body portion 824.

The coil portion 830 has an inner layer 822 and an outer layer 831 formed by one wire L.
Among these, the outer layer 831 as the outermost layer winds a part of the wire L forming the winding part 8221 around the outer periphery of the winding part 8221 after the formation of the winding part 8221 on the tip side in the inner layer 822. It is formed in this way. More specifically, the outer layer 831 winds the wire L substantially half a circumference along the outer periphery of the winding portion 8221 on the distal end side without making one turn, and then pulls the wire L back to the distal end side again. Then, the end portion of the wire L forming the outer layer 831 is connected to the main body portion 824. For this reason, after the formation of the main body portion 824, the diameter dimension of the outer layer 831 is larger than the maximum diameter dimension of the main body portion 824 having substantially the same diameter dimension as the inner layer 822. Projecting from the main body 824. The formation position of the outer layer 831 is set on the side where the trigger line 53 is disposed. Further, the length of the wire L forming the outer layer 831 is shorter than the length of the wire L forming the inner layer 822.

According to the projector of the present embodiment described above, in addition to the same effects as the above-described (1) to (4) and (6) to (8), the following effects can be achieved.
(13) The outer layer 831 of the coil portion 830 is formed on the distal end side of the large diameter portion 82E so as to protrude to the outside of the main body portion 824. The end of the wire L forming the outer layer 831 is connected to the main body 824. According to this, in addition to being able to position the discharge starting point at the start of lighting of the arc tube 51E on the outer layer 831 positioned on the distal end side of the coil portion 830, it is possible to shorten the distance from the discharge starting point to the main body portion 824. Therefore, conduction of heat generated by the discharge to the main body 824 can be accelerated. Accordingly, since the temperature of the main body 824 can be quickly increased, the transition to the arc discharge between the main bodies 824 of the pair of electrodes 8E can be quickly performed. Can be improved.

[6. Sixth Embodiment]
Next, a projector according to a sixth embodiment of the invention will be described.
The projector according to this embodiment has the same configuration as that of the projector 1 described above, but in the projector 1, the outer layer 823 that is the outermost layer of the coil unit 821 is connected to the main body unit 824, whereas The projector according to the embodiment is different from the projector 1 described above in that the outermost layer of the coil unit is not connected to the main body unit 824. 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. 9 is a side view showing the electrode 8FL of the arc tube 51F 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 51F is provided instead of the arc tube 51A. The arc tube 51F has the same configuration as the arc tube 51A except that the arc tube 51F includes a pair of electrodes 8F instead of the pair of electrodes 8A.
The pair of electrodes 8F includes an electrode 8FL disposed on the sealing portion 512 side and an electrode (not shown) disposed on the sealing portion 513 side, and these have the same configuration.
Among these, as shown in FIG. 9, the electrode 8FL is configured to include a shaft portion 81 and a large-diameter portion 82F that is formed on the distal end side of the shaft portion 81 and has a larger diameter than the shaft portion 81. ing.

The large-diameter portion 82F includes a coil portion 832 and a main body portion 824 located on the distal end side (side adjacent to the other electrode) of the coil portion 832. The coil portion 832 includes a coil portion main body 833 and a spiral shape. Part 834.
Among these, the coil part main body 833 is a two-layer coil formed by winding the wire L1 described above a plurality of times along the circumferential direction of the shaft part 81. The coil part main body 833 forms each layer of the coil part main body 833 and is formed densely so that seven adjacent winding parts 8332 are in contact with each other along the axial direction of the shaft part 81. . The outer layer 8331 of the coil portion main body 833 corresponds to the inner layer of the present invention. In addition, although the coil part main body 833 was made into the coil of 2 layer winding in this embodiment, it is not restricted to this, 1 layer may be sufficient and 3 layers or more may be sufficient. Even in these cases, the outer layer of the coil portion main body 833 corresponds to the inner layer of the present invention.

After the coil part main body 833 and the main body part 824 are formed by a manufacturing process similar to the above-described manufacturing process, the spiral part 834 is formed of a member having one winding part 8341 formed by winding the wire L3 in advance. The coil portion main body 833 is formed by being screwed outside the layer 8331. For this reason, the spiral portion 834 forms the outermost layer of the coil portion 832, and the spiral portion 834 corresponds to the outermost layer of the present invention. The wire L3 is made of the same material as the wire L2 described above, but the wire diameter of the wire L3 is substantially the same as the wire diameter of the wire L1.
Such a spiral portion 834 is formed sparsely so that the wire L2 does not contact each other along the axial direction of the coil portion 832. The diameter of the spiral portion 834 is larger than the maximum diameter of the main body portion 824, and the spiral portion 834 protrudes outside the main body portion 824 when viewed from the axial direction of the electrode 8FL.

  Although the spiral portion 834 is located on the distal end side of the large diameter portion 82F, the distal end side end portion of the spiral portion 834 and the main body portion 824 are not heat-sealed. Specifically, the spiral portion 834 is disposed so as to straddle the coil portion main body 833 and the main body portion 824, and is in contact with these, but the coil portion main body 833 and the main body portion 824 are not thermally fused. . For this reason, the spiral portion 834 is compared to the case where the spiral portion 834 is heat-sealed to the coil portion main body 833 and the main body portion 824, and compared to the coil portion main body 833 and the main body portion 824. High thermal resistance.

  In such an electrode 8F, at the start of lighting of the arc tube 51F, the discharge starting point is positioned on the spiral portion 834 which is located outside the electrode 8F and where the electric field (electric field) is concentrated. Specifically, the discharge starting point is positioned at a position facing the trigger line 53 in the spiral portion 834. At this time, since the spiral portion 834 has a high thermal resistance, the spiral portion 834 is quickly heated by the heat generated by the discharge at the discharge starting point. The heat of the spiral portion 834 is conducted at the contact portion between the coil portion main body 833 and the main body portion 824, and as a result, the main body portion 824 is heated.

According to the projector of the present embodiment described above, the same effects as the above (1) to (5), (8), (11), and (12) can be obtained, and the following effects can be obtained. Can do.
(14) Since the contact area between the spiral portion 834 serving as the outermost layer of the large diameter portion 82F and the coil portion main body 833 and the main body portion 824 can be reduced, the thermal resistance of the spiral portion 834 is increased. Can do. Therefore, in the large diameter portion 82F, the discharge starting point can be reliably positioned at the spiral portion 834 that is easily heated. In addition, the spiral portion 834 which is the outermost layer of the coil portion 832 is formed by screwing a previously manufactured member into the coil portion main body 833 and the main body portion 834. Therefore, the wire forming the coil portion main body 833. The outermost layer of the coil portion 832 in which the wire rods do not contact each other along the axial direction can be easily formed as compared with the case where the L1 is wound back.
Note that if the wire diameter of the wire L3 forming the spiral portion 834 is made smaller than the wire diameter of the wire L1 forming the coil portion main body 833, the heat capacity of the spiral portion 834 can be further reduced. Therefore, the temperature rise in the vicinity of the discharge starting point in the spiral portion 834 that is the outer layer of the coil portion 832 can be accelerated.

[7. 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 to third and fifth embodiments, the coil portions 821, 825, and 827 each have two layers. In the fourth embodiment, the coil portion 829 has three layers. In the sixth embodiment, the coil portion main body 833 has two layers, but the present invention is not limited to this. In other words, if the configuration has two or more layers, the number of layers in the coil portion may be set as appropriate based on the wattage of the arc tube, and the number of layers in the coil portion main body is also one or more. Good.

  In the first, third, and fourth embodiments, the outer layers 823 and 828 of the coil portions 821 and 827 and the third layer 8293 of the coil portion 829 are provided with two winding portions 8231, 8281, and 82931, respectively. Further, in the sixth embodiment, the spiral portion 834 includes one winding portion 8341. However, the present invention is not limited to this. That is, the number of winding parts of the outer layer constituting the coil part and the number of winding parts of the spiral part may be set as appropriate, and as shown in the second and fifth embodiments, It is good also as a structure which does not have a winding part.

  In the first to fifth embodiments, the body portion 824 is formed by dissolving the shaft portion 81 and the tips of the coil portions 821, 825, 827, 829, and 830, and in this process, the outer layers 823, 826, 828, 831 and the tip of the third layer 8293 are connected to the main body 824, but the present invention is not limited to this. For example, the main body portion may be formed by forming the tip of the shaft portion 81 in a substantially arc shape, and the coil portion may be formed so as to be connected to the main body portion.

In the third embodiment, the inner layer 822 and the outer layer 828 are formed by the wire materials L1 and L2 having different wire diameters, respectively, but the present invention is not limited to this. That is, the inner layer and the outer layer may be formed so that the inner layer and the outer layer have different wire diameters by using a single wire having different portions of the wire diameter.
In the first, second, third, and fifth embodiments, the coil portions 821, 827, 829, and 830 are formed by one wire L. However, the present invention is not limited to this, and the coil portion. These layers may be formed of different wire materials.

  In the third embodiment, the wire L1 for forming the inner layer 822 is formed of tungsten, and the wire L2 for forming the outer layer 828 is formed of a material obtained by adding a starting auxiliary substance to tungsten. In the sixth embodiment, the coil body 833 is formed of the wire L1, and the spiral portion 834 is formed of the wire L3 containing the starting auxiliary substance. However, the present invention is not limited to this, and the wires L1, L2, and L3 may be formed of the same material (for example, tungsten). Moreover, you may form not only these wire L1, L2, L3 but the wire L with another material.

  In each of the above embodiments, the arc tubes 51A, 51B, 51C, 51D, 51E, and 51F each have a pair of electrodes 8A, 8B, 8C, 8D, 8E, and 8F having the same configuration. Not limited to. In other words, at least one of the pair of electrodes may have the above-described configuration.

  In the sixth embodiment, the spiral portion 834 is not thermally fused to the coil portion main body 833 and the main body portion 824, but the present invention is not limited to this. That is, a part may be heat-sealed to at least one of the coil part main body 833 and the main body part 824. That is, all of the contact surfaces of the spiral portion 834 and the coil portion main body 833 and the main body portion 824 may not be thermally fused to each other.

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. However, any other configuration may be used as long as the light modulation device forms an optical image by modulating the incident light beam according to image information. 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, 51D, 51E, and 51F 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 figure explaining the manufacturing process of the electrode in the said embodiment. The side view which shows the electrode of the arc tube with which the projector which concerns on 2nd Embodiment of this invention is provided. The side view which shows the electrode of the arc tube with which the projector which concerns on 3rd Embodiment of this invention is provided. The side view which shows the electrode of the arc tube with which the projector which concerns on 4th Embodiment of this invention is provided. The side view which shows the electrode of the arc tube with which the projector which concerns on 5th Embodiment of this invention is provided. The side view which shows the electrode of the arc tube with which the projector which concerns on 6th Embodiment of this invention is provided.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Projector, 3 ... Projection lens (projection optical apparatus), 411 ... Light source device, 442 (442R, 442G, 442B) ... Liquid crystal panel (light modulation apparatus), 5 ... Discharge lamp, 51A, 51B, 51C, 51D, 51E , 51F ... arc tube, 511 ... light emitting part, 6 ... main reflecting mirror (reflecting mirror), 8A, 8B, 8C, 8D, 8E, 8F ... electrode, 81 ... shaft part, 82A, 82B, 82C, 82D, 82E, 82F ... large diameter part, 821,825,827,829,830,832 ... coil part, 822 ... inner layer, 823,826,828,831 ... outer layer (outermost layer), 824 ... main body part, 834 ... spiral part ( Outermost layer), 8231, 8281, 89311, 8341 ... winding part, 8292 ... second layer (inner layer), 8293 ... third layer (outermost layer), 8331 ... layer (inner layer), L, L1, L2, L3 Wire.

Claims (7)

A light-emitting tube having a light-emitting portion in which a pair of electrodes are arranged and discharges and emits light between the pair of electrodes,
At least one of the pair of electrodes is
A shaft portion and a large-diameter portion formed on the other electrode side of the shaft portion and having a larger diameter than the shaft portion;
The large diameter portion is
A main body portion that is formed on the other electrode side and discharges in a steady lighting state of the arc tube,
A coil portion that is provided on the side of the main body portion that is separated from the other electrode, and is formed by winding a plurality of layers of one wire,
The outermost layer in the coil part is formed so that the wire does not contact each other along the axial direction of the coil part,
An inner layer, which is a layer adjacent to the outermost layer, is formed such that the wires are in contact with each other along the axial direction of the coil portion. The arc tube of claim 1, wherein
The arc tube according to claim 1, wherein the number of windings of the wire in the outermost layer is less than the number of windings of the wire in the inner layer. The arc tube according to claim 1 or 2,
The diameter of the outermost layer is larger than the maximum diameter of the main body, and the arc tube is characterized in that The arc tube according to any one of claims 1 to 3,
The outermost layer includes at least one winding portion that is one turn of the wire along the outer periphery of the inner layer. The arc tube according to any one of claims 1 to 4, wherein
An arc tube characterized in that an end of the wire forming the outermost layer on the main body side is connected to the main body. A light source device comprising: the arc tube according to any one of claims 1 to 5 ; and a reflecting mirror that aligns light emitted from the arc tube in one direction and emits it as a light beam. A light source device according to claim 6 , 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. projector.

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