JP2008243518A - Arc tube, light source device and projector - Google Patents

Abstract

An arc tube capable of further increasing the brightness while extending the life is provided.
An arc tube 20 comprising a bulb portion 30 and a pair of sealing portions 40, 50 extending on both sides of the bulb portion 30. An intermediate position between the pair of electrodes 42 and 52 in the cross section of the bulb portion 30 when the arc tube 20 is cut along a vertical virtual plane including the optical axis is a point P, and against the gravity on the inner surface of the bulb portion 30. The lowermost position is point A, the uppermost position with respect to gravity on the inner surface of the tube portion 30 is point B, and the lowermost position with respect to gravity on the outer surface of the tube portion 30 is the point B. A point C is defined as a point D that is the uppermost position with respect to gravity on the outer surface of the tube portion 30, a distance from the point P to the point A is L _A, and a distance from the point P to the point B is L _B. , the distance from the point P to the point C and _{L C,} and the distance from the point P to the point D was _{L D, "L} a _{<L B"} and _{"(L C -L a)> (} L D - L _B ) ”is satisfied.
[Selection] Figure 2

Description

  The present invention relates to an arc tube, a light source device, and a projector.

  2. Description of the Related Art Conventionally, as an arc tube for a light source device of a projector, an arc tube including a tube bulb portion including a pair of electrodes and a pair of sealing portions extending on both sides of the bulb portion is known (for example, Patent Documents). 1).

JP 2005-5183 A

  By the way, in the conventional arc tube, the temperature of the upper region with respect to the gravity on the inner surface of the bulb portion is likely to be particularly high due to thermal convection, and the temperature exceeds the allowable temperature of the base material constituting the bulb portion. In this case, local swelling may occur or whitening may occur in the upper region of the outer surface of the tube portion. Whitening is a phenomenon in which the base material constituting the tube portion becomes clouded and devitrified. When local swelling occurs in the bulb portion, the arc tube may rupture due to a decrease in strength. Further, when the tube bulb portion is whitened, light transmission is hindered at the whitened portion, and as a result, heat is generated and the temperature of the arc tube further rises. As a result, the arc tube may burst. .

  In order to suppress the temperature rise in the upper region on the inner surface of the tube portion, it is conceivable to cool the arc tube with a cooling fan. However, in the conventional arc tube, as described above, the temperature of the upper region on the inner surface of the tube portion is likely to increase due to thermal convection, and the temperature of the upper region and the lower region on the inner surface of the tube portion. Therefore, when the tube part is cooled in order to cool the temperature of the upper region on the inner surface of the tube part to a predetermined temperature or less, the temperature difference between the outer surface and the inner surface of the tube part is The lower region may be cooled more than necessary, and the lower region on the inner surface of the tube portion may be blackened. Blackening means that the evaporating performance of the encapsulated material (eg, mercury, rare gas, metal halide, etc.) enclosed in the tube part is reduced, and the efficiency of the halogen cycle is reduced. It is a phenomenon that adheres to the inner wall of the part. When the tube portion is blackened in this way, light is absorbed at the blackened portion, which may reduce the light amount of the arc tube or damage the arc tube.

  Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide an arc tube capable of further increasing the brightness while extending the life. It is another object of the present invention to provide a light source device and a projector provided with such an excellent arc tube.

  In order to solve the above-described problem, the present inventor conducted extensive research on means for suppressing the temperature increase in the upper region on the inner surface of the tube portion, and as a result, “the tube portion from the intermediate position of the pair of electrodes” The distance from the middle position of the pair of electrodes to the uppermost position relative to gravity on the inner surface of the tube is longer than the "distance from the middle position of the pair of electrodes to the lowermost position relative to gravity on the inner surface of the bulb part". In addition, if the tube bulb portion of the arc tube is configured so that the wall thickness of the upper tube wall in the bulb portion is thinner than the wall thickness of the lower tube wall, The temperature rise of the region can be suppressed, and the temperature difference between the temperature of the upper region and the temperature of the lower region on the inner surface of the tube portion can be reduced, and as a result, the life can be extended. It will be possible to further increase the brightness. Conceive, it has led to the completion of the present invention.

That is, the arc tube of the present invention is an arc tube comprising a tube bulb portion incorporating a pair of electrodes arranged along the optical axis, and a pair of sealing portions extending on both sides of the bulb portion, An intermediate position of the pair of electrodes in the cross section of the bulb portion when the arc tube is cut in a vertical virtual plane including the optical axis is a point P, and the most against gravity on the inner surface of the bulb portion. The lower position is point A, the uppermost position with respect to gravity on the inner surface of the tube part is point B, and the lowermost position with respect to gravity on the outer surface of the tube part is point It is C, and uppermost a position of the point D with respect to the gravity on the outer surface of the tube unit, the distance from the point P to the point a and L _a, the distance from the point P to the point B and L _B, When the distance from the point P to the point C is L _C and the distance from the point P to the point D is L _D , Characterized by satisfying the relation of _"L A _{<L B"} and _{"(L C -L A)> (} L D -L B) ."

For this reason, according to the arc tube of the present invention, from the relationship of “L _A <L _B ”, the intermediate position (P) of the pair of electrodes serving as the center of the heat source and the upper region on the inner surface of the tube portion The distance can be made longer than the distance between the intermediate position (P) of the pair of electrodes and the lower region on the inner surface of the tube portion. In other words, the upper region on the inner surface of the tube portion can be separated from the heat source to some extent, so that the temperature increase in the upper region on the inner surface of the tube portion can be suppressed. As a result, it is possible to suppress the occurrence of local swelling and whitening in the upper region on the outer surface of the tube portion, and it is possible to suppress the arc tube from bursting.

Further, according to the arc tube of the present invention, the wall thickness of the upper tube wall in the tube portion is less than that of the lower tube wall due to the relationship of “(L _C −L _A )> (L _D −L _B )”. Since it is thinner than the wall thickness, when the entire tube portion is cooled in the same manner, the upper region on the inner surface of the tube portion is more easily cooled than the lower region on the inner surface of the tube portion. . This makes it possible to reduce the temperature difference between the temperature of the upper region and the temperature of the lower region on the inner surface of the tube portion, so that the temperature of the upper region on the inner surface of the tube portion is equal to or lower than a predetermined temperature. Even in the case where the cooling is performed, it is possible to prevent the lower region of the inner surface of the tube portion from being cooled more than necessary. As a result, it is possible to suppress a decrease in the light amount of the arc tube and damage to the arc tube due to blackening.

  Therefore, the arc tube of the present invention is an arc tube capable of further increasing the brightness while extending the life.

In the arc tube of the present invention, it is preferable that “1 <L _B / L _A <2.5”.

As will be described in detail in a test example to be described later, when the relationship of “1 <L _B / L _A <2.5” is satisfied, it is possible to suppress a temperature increase in the upper region on the inner surface of the tube portion. In addition, the temperature difference between the temperature of the upper region and the temperature of the lower region on the inner surface of the tube portion can be reduced.

  The light source device of the present invention includes a light-emitting tube according to the present invention and a reflector having a reflective concave surface that is disposed on one sealing portion side of the light-emitting tube and reflects light from the light-emitting tube toward an illuminated region side. It is provided with these.

  For this reason, according to the light source device of the present invention, since the above-described excellent arc tube is provided, the light source device can achieve higher luminance while extending its life.

  In the light source device of the present invention, the reflection concave surface of the reflector is refracted when light emitted from the center of the tube portion through the tube wall of the tube portion is refracted by the tube wall. It is preferable to have a curved surface shape that corrects and reflects.

  By configuring in this way, it becomes possible to correctly reflect the light radiated through the tube wall (upper tube wall and lower tube wall) of the bulb portion toward the subsequent optical element. . For example, when the reflector is an ellipsoidal reflector, it is possible to reflect light emitted through the tube wall of the bulb portion toward the second focal position of the ellipsoidal reflector. Further, when the reflector is a parabolic reflector, light emitted through the tube wall of the bulb portion can be reflected toward the illuminated region as light substantially parallel to the illumination optical axis. .

  In the light source device of the present invention, the bulb portion is disposed on the other sealing portion side of the arc tube so as to cover the outer surface of the bulb portion on the illuminated region side, and the light from the bulb portion is transmitted to the bulb portion. A secondary mirror having a reflective concave surface that reflects toward the tube, wherein the reflective concave surface of the secondary mirror is configured to receive light emitted from the center of the tube portion through the tube wall of the tube portion. When the light is refracted, it is preferable to have a curved surface shape that reflects and corrects the refraction.

By the way, it is possible to improve the light utilization efficiency and to reduce the size of the reflector by disposing the reflecting means in the sealing portion of the arc tube, thereby realizing a high-luminance and compact light source device. However, since almost half of the bulb portion is covered by the reflecting means, the light source device in which the reflecting means is disposed in the sealing portion of the arc tube has such a reflecting means. There is a tendency that the temperature of the bulb portion tends to be higher than that of the light source device that is not used.
In the present invention, as described above, it is possible to suppress the overall temperature of the tube bulb portion from being increased, and thus the reflecting means is disposed in the sealing portion of the arc tube as described above. This is particularly effective for the light source device.

  A projector according to the present invention includes a light source device according to the present invention, an electro-optic modulation device that modulates an illumination light beam from the light source device according to image information, and a projection optical system that projects light modulated by the electro-optic modulation device. It is characterized by providing.

  For this reason, according to the projector of the present invention, since the above-described excellent light source device is provided, the projector has a long-life light source device and a high brightness.

  In the projector according to the aspect of the invention, it is preferable that the projector further includes a cooling mechanism for cooling the light source device.

  With this configuration, it is possible to suppress the temperature rise of the light source device, and it is possible to further increase the luminance while extending the life of the light source device.

  The arc tube, light source device, and projector of the present invention will be described below based on the embodiments shown in the drawings.

[Embodiment]
FIG. 1 is a top view schematically showing an optical system of a projector 1000 according to the embodiment. FIG. 2 is a view for explaining the arc tube 20 and the light source device 110 according to the embodiment. 2A is a side view schematically showing the light source device 110, and FIG. 2B is a cross-sectional view of the peripheral portion of the bulb portion 30 in the arc tube 20 as viewed from the side.

In the following description, three directions orthogonal to each other are defined as a z-axis direction (illumination optical axis OC direction in FIG. 1), an x-axis direction (a direction parallel to the paper surface in FIG. 1 and perpendicular to the z-axis), and y. Let it be an axial direction (a direction perpendicular to the paper surface in FIG. 1 and perpendicular to the z-axis).
Further, in the following description, the case where projector 1000 is arranged in a so-called stationary state is exemplarily shown, and therefore the direction of gravity is the lower direction (for example, the y (−) direction in FIG. 2A). It becomes.

  As shown in FIG. 1, the projector 1000 according to the embodiment separates the illumination device 100 and the illumination light flux from the illumination device 100 into three color lights of red light, green light, and blue light and guides them to the illuminated area. A color separation light guide optical system 200, and three liquid crystal devices 400R, 400G, and 400B as electro-optic modulation devices that modulate each of the three color lights separated by the color separation light guide optical system 200 according to image information; A cross dichroic prism 500 that synthesizes the color lights modulated by the three liquid crystal devices 400R, 400G, and 400B, a projection optical system 600 that projects the light synthesized by the cross dichroic prism 500 onto a projection surface such as a screen SCR, and cooling A projector including a mechanism 700 (not shown).

  The illuminating device 100 includes a light source device 110 that emits an illumination light beam toward the illuminated region, a concave lens 90 that emits the focused light from the light source device 110 as substantially parallel light, and a plurality of portions of the illumination light beam emitted from the concave lens 90. A first lens array 120 having a plurality of first small lenses 122 for dividing the light beam, and a second lens having a plurality of second small lenses 132 corresponding to the plurality of first small lenses 122 of the first lens array 120. The array 130, the polarization conversion element 140 that converts each partial light beam from the second lens array 130 into approximately one type of linearly polarized light having the same polarization direction and emits it, and each partial light beam emitted from the polarization conversion element 140 And a superimposing lens 150 for superimposing in the illuminated area.

  As shown in FIGS. 1 and 2A, the light source device 110 includes an ellipsoidal reflector 10 as a reflector, an arc tube 20 having a light emission center near the first focal point of the ellipsoidal reflector 10, and a reflecting means. And a secondary mirror 60. The light source device 110 emits a light beam having the illumination optical axis OC as a central axis.

  As shown in FIG. 2, the arc tube 20 includes a tube bulb portion 30 including a pair of electrodes 42 and 52 arranged along the illumination optical axis OC, and a pair of sealing portions extending on both sides of the tube bulb portion 30. 40, 50, a pair of metal foils 44, 54 sealed in the pair of sealing portions 40, 50, respectively, and a pair of lead wires 46, electrically connected to the pair of metal foils 44, 54, respectively. 56.

If the conditions of the constituent elements of the arc tube 20 are exemplarily shown, the tube portion 30 and the sealing portions 40 and 50 are made of, for example, quartz glass, and mercury or a rare gas is contained in the tube portion 30. And a small amount of halogen is enclosed. The electrodes 42 and 52 are, for example, tungsten electrodes, and the metal foils 44, 54 are, for example, molybdenum foils. The lead wires 46 and 56 are made of, for example, molybdenum or tungsten.
Further, as the arc tube 20, various arc tubes that emit light with high luminance can be employed, for example, a high pressure mercury lamp, an ultra high pressure mercury lamp, a metal halide lamp, or the like.

As shown in FIG. 2B, the tube portion 30 is pointed at an intermediate position between the pair of electrodes 42 and 52 in the cross section of the tube portion 30 when cut along a vertical virtual plane including the illumination optical axis OC. P is defined as a point A that is the lowest position with respect to gravity on the inner surface of the tube portion 30, a point B is a position that is the uppermost position with respect to gravity on the inner surface of the tube portion 30, and the tube portion 30. The position on the outer surface of the tube part 30 that is the lowest side with respect to gravity is the point C, the position that is the uppermost side on the outer surface of the tube portion 30 with respect to the gravity is the point D, and the distance from the point P to the point A is L _A and then, the distance from the point P to the point B and L _B, the distance from the point P to the point C and L _C, the distance from the point P to the point D and L _D, the distance from the point C to point D Let L be. At this time, in the arc tube 20 according to the embodiment, “L _A <L _B ” and “(L _C −L _A )> (L _D −L _B )”, and further “L _C = L _D = L / The bulb portion 30 of the arc tube 20 is configured so as to satisfy the relationship “2”.

  As shown in FIG. 2A, the ellipsoidal reflector 10 is radiated from the arc tube 20 and the opening 12 for inserting and fixing the seal portion (one seal portion) 40 of the arc tube 20. And a reflective concave surface that reflects light toward the second focal position. The ellipsoidal reflector 10 is fixed to the sealing portion 40 of the arc tube 20 with an inorganic adhesive such as cement filled in the opening 12 of the ellipsoidal reflector 10.

  When the light radiated from the center of the tube portion 30 through the upper tube wall 36 and the lower tube wall 38 from the center of the tube portion 30 is refracted by the tube walls 36, 38, the reflection concave surface 14 It has a curved surface shape that reflects and corrects refraction.

For example, crystallized glass, alumina (Al ₂ O ₃ ), or the like can be suitably used as the material for the base material constituting the reflective concave surface 14. On the inner surface of the reflective concave surface 14, for example, a visible light reflecting layer made of a dielectric multilayer film of titanium oxide (TiO ₂ ) and silicon oxide (SiO ₂ ) is formed.

  The secondary mirror 60 is a reflecting means that covers substantially half of the bulb portion 30 and is disposed to face the reflective concave surface 14 of the elliptical reflector 10. The secondary mirror 60 is a sealing portion (the other sealing portion) 50 of the arc tube 20. And a reflective concave surface 64 that reflects the light emitted from the arc tube 20 toward the illuminated area toward the arc tube 20. The light reflected by the secondary mirror 60 passes through the arc tube 20 and enters the ellipsoidal reflector 10. The secondary mirror 60 is fixed to the sealing portion 50 of the arc tube 20 with an inorganic adhesive such as cement filled in the opening 62 of the secondary mirror 60.

  When the light radiated from the center of the tube bulb portion 30 through the upper tube wall 36 and the lower tube wall 38 from the center of the bulb portion 30 is refracted by the tube walls 36, 38, the reflection concave surface 64 It has a curved surface shape that reflects and corrects refraction.

As a material constituting the reflective concave surface 64, for example, translucent alumina is used. Thereby, the heat dissipation in the secondary mirror 60 can be improved. In addition to alumina, materials such as quartz glass, sapphire, and ruby may be used.
On the inner surface of the reflective concave surface 64, for example, a reflective layer made of a dielectric multilayer film of tantalum oxide (Ta ₂ O ₅ ) and silicon oxide (SiO ₂ ) is formed.

  As shown in FIG. 1, the concave lens 90 is disposed on the illuminated area side of the ellipsoidal reflector 10. The light from the ellipsoidal reflector 10 is emitted toward the first lens array 120.

  The first lens array 120 has a function as a light beam splitting optical element that splits the light from the concave lens 90 into a plurality of partial light beams, and a plurality of first small lenses 122 are arranged in a plane orthogonal to the illumination optical axis OC. It has a configuration arranged in a matrix of rows and columns. Although not illustrated, the outer shape of the first small lens 122 is similar to the outer shape of the image forming area of the liquid crystal devices 400R, 400G, and 400B.

  The second lens array 130 has a function of forming an image of each first small lens 122 of the first lens array 120 in the vicinity of the image forming area of the liquid crystal devices 400R, 400G, and 400B together with the superimposing lens 150. The second lens array 130 has substantially the same configuration as the first lens array 120, and a plurality of second small lenses 132 are arranged in a matrix of a plurality of rows and a plurality of columns in a plane orthogonal to the illumination optical axis OC. Have a configuration.

The polarization conversion element 140 is a polarization conversion element that emits the polarization direction of each partial light beam divided by the first lens array 120 as approximately one type of linearly polarized light having a uniform polarization direction.
The polarization conversion element 140 transmits one linearly polarized light component among the polarized light components included in the illumination light beam from the light source device 110 and reflects the other linearly polarized light component in a direction perpendicular to the illumination optical axis OC; A reflection layer that reflects the other linearly polarized light component reflected by the polarization separating layer in a direction parallel to the illumination optical axis OC, and a phase difference that converts one linearly polarized light component transmitted through the polarization separating layer into the other linearly polarized light component. And a board.

  The superimposing lens 150 condenses a plurality of partial light beams that have passed through the first lens array 120, the second lens array 130, and the polarization conversion element 140, and superimposes them on the vicinity of the image forming regions of the liquid crystal devices 400R, 400G, and 400B. It is an element. The superimposing lens 150 is arranged so that the optical axis of the superimposing lens 150 and the illumination optical axis OC of the illumination device 100 substantially coincide. The superimposing lens 150 may be composed of a compound lens in which a plurality of lenses are combined.

  The color separation light guide optical system 200 includes dichroic mirrors 210 and 220, reflection mirrors 230, 240 and 250, an incident side lens 260, and a relay lens 270. The color separation light guide optical system 200 separates the illumination light beam emitted from the superimposing lens 150 into three color lights of red light, green light, and blue light, and each of the three color liquid crystal devices 400R to be illuminated. , 400G, 400B.

The liquid crystal devices 400 </ b> R, 400 </ b> G, and 400 </ b> B modulate the illumination light beam according to the image information and are the illumination target of the illumination device 100.
The liquid crystal devices 400R, 400G, and 400B are a pair of transparent glass substrates in which a liquid crystal that is an electro-optical material is hermetically sealed. For example, an incident light that will be described later is used according to given image information using a polysilicon TFT as a switching element. Modulates the polarization direction of one type of linearly polarized light emitted from the side polarizing plate.

  Condensing lenses 300R, 300G, and 300B are disposed in the front stage of the optical path of the liquid crystal devices 400R, 400G, and 400B.

  Although not shown here, incident-side polarizing plates are interposed between the condenser lenses 300R, 300G, and 300B and the liquid crystal devices 400R, 400G, and 400B, and the liquid crystal devices 400R, 400G, and 400B are disposed. Between the 400B and the cross dichroic prism 500, an exit side polarizing plate is interposed. The incident-side polarizing plate, the liquid crystal devices 400R, 400G, and 400B and the exit-side polarizing plate modulate light of each color light incident thereon.

The cross dichroic prism 500 is an optical element that forms a color image by synthesizing an optical image modulated for each color light emitted from the exit side polarizing plate. The cross dichroic prism 500 has a substantially square shape in plan view in which four right-angle prisms are bonded together, and a dielectric multilayer film is formed on a substantially X-shaped interface in which the right-angle prisms are bonded together. The dielectric multilayer film formed at one of the substantially X-shaped interfaces reflects red light, and the dielectric multilayer film formed at the other interface reflects blue light. By these dielectric multilayer films, the red light and the blue light are bent and aligned with the traveling direction of the green light, so that the three color lights are synthesized.

  The color image emitted from the cross dichroic prism 500 is enlarged and projected by the projection optical system 600 to form a large screen image on the screen SCR.

  The projector 1000 is provided with a cooling mechanism 700 (not shown). The cooling mechanism 700 includes at least a cooling fan 710 that cools the light source device 110 and a cooling air flow path 720 that allows cooling air from the cooling fan 710 to pass through (both not shown). The cooling mechanism 700 may be configured to cool not only the light source device 110 but also other optical elements (for example, the liquid crystal devices 400R, 400G, and 400B).

According to the arc tube 20 according to the embodiment configured as described above, the tube position 30 and the intermediate position P between the pair of electrodes 42 and 52 serving as the center of the heat source, based on the relationship of “L _A <L _B ”. It is possible to make the distance from the upper region 32 on the inner surface longer than the distance between the intermediate position P of the pair of electrodes 42 and 52 and the lower region 34 on the inner surface of the tube portion 30. That is, since the upper region 32 on the inner surface of the tube portion 30 can be separated from the heat source to some extent, the temperature increase of the upper region 32 on the inner surface of the tube portion 30 can be suppressed. As a result, it is possible to suppress the occurrence of local swelling or whitening in the upper region 33 on the outer surface of the tube portion 30, and it is possible to suppress the arc tube 20 from bursting. .

Further, according to the light-emitting tube 20 according to the embodiment, _{"(L C -L A)> (} L D -L B) " from the relationship, the lower is the thickness of the upper wall 36 of the tube spherical portion 30 Therefore, when the entire tube portion 30 is cooled in the same manner, the upper region 32 on the inner surface of the tube portion 30 is lower on the inner surface of the tube portion 30. It becomes easier to cool than the region 34 on the side. As a result, the temperature difference between the temperature of the upper region 32 and the temperature of the lower region 34 on the inner surface of the tube portion 30 can be reduced. Even when the temperature is cooled to a predetermined temperature or lower, it is possible to prevent the lower region 34 on the inner surface of the tube portion 30 from being cooled more than necessary. As a result, it is possible to suppress a decrease in the light amount of the arc tube 20 due to blackening and the occurrence of damage to the arc tube 20.

  Therefore, the arc tube 20 according to the embodiment is an arc tube capable of further increasing the brightness while extending the life.

As will be described in detail in a test example to be described later, in the arc tube 20 according to the embodiment, in order to satisfy the relationship of “1 <L _B / L _A <2.5”, the upper region on the inner surface of the tube portion 30 It is possible to suppress the temperature rise of 32 and to reduce the temperature difference between the temperature of the upper region 32 and the temperature of the lower region 34 on the inner surface of the tube portion 30.

  Since the light source device 110 according to the embodiment includes the excellent arc tube 20 described above, it becomes a light source device capable of further increasing the brightness while extending the life.

  In the light source device 110 according to the embodiment, the reflection concave surface 14 of the ellipsoidal reflector 10 is configured such that light emitted from the center of the tube portion 30 through the tube walls 36 and 38 of the tube portion 30 is emitted from the tube wall 36. When the light beam is refracted at 38, the light beam radiates through the tube walls 36 and 38 of the bulb portion 30 so that the light is radiated by correcting the refraction. It becomes possible to reflect toward the position.

In the light source device 110 according to the embodiment, the light source device 110 is disposed on the sealing portion 50 side so as to cover the outer surface of the tube portion 30 on the illuminated region side, and the light from the tube portion 30 is directed toward the tube portion 30. A secondary mirror 60 is further provided as reflecting means for reflecting. Thereby, since the light radiated | emitted from the bulb part 30 to the to-be-illuminated area side is reflected toward the ellipsoidal reflector 10 by the secondary mirror 60, it is radiated | emitted from the to-be-illuminated part side to the to-be-illuminated area side, and is used effectively effectively It is possible to effectively use light that has not been used. For this reason, the brightness of the light source device 110 can be increased.
Further, it is not necessary to set the size of the ellipsoidal reflector 10 so as to cover the end of the arc tube 20 to be illuminated, and the ellipsoidal reflector 10 can be reduced in size, as a result. A compact light source device can be realized. Furthermore, since the ellipsoidal reflector 10 can be miniaturized, the size of the optical element arranged in the latter stage of the optical path can be reduced, so that a compact projector can be obtained.

By the way, by disposing the secondary mirror 60 in the sealing portion 50 of the arc tube 20, it becomes possible to improve the light utilization efficiency and to reduce the size of the ellipsoidal reflector 10, and to achieve high brightness and compactness. However, since approximately half of the bulb portion 30 is covered by the secondary mirror 60, the light source in which the secondary mirror 60 is disposed in the sealing portion 50 of the arc tube 20. The device 110 tends to have a higher temperature of the tube portion 30 than a light source device in which such a secondary mirror is not provided.
Since the present invention can suppress the overall temperature of the tube portion 30 from becoming high as described above, the secondary mirror 60 is provided on the sealing portion 50 of the arc tube 20 as described above. This is particularly effective for the light source device 110 provided.

  Since the projector 1000 according to the embodiment includes the excellent light source device 110 described above, the projector 1000 includes a long-life light source device and is a high-brightness projector.

  The projector 1000 according to the embodiment further includes a cooling mechanism 700 that cools the light source device 110. Therefore, the temperature increase of the light source device 110 can be suppressed, and the light source device 110 can have a longer lifetime and higher brightness. Can be achieved.

[Test example]
The test example is a test example for confirming that there is an effect of the present invention when the relationship of “1 <L _B / L _A <2.5” is established.

  Table 1 is a table | surface which shows the determination result of each arc_tube | light_emitting_tube in a test example.

  FIG. 3 is a cross-sectional view of the peripheral portion of the bulb portion 30a in the arc tube 20a according to the comparative example as seen from the side.

In the test example, when the arc tube is cooled so that the temperature of the lower region on the inner surface of the bulb portion is constant by changing the shape of the discharge space of the bulb portion, the upper side on the inner surface of the bulb portion The temperature of the region was simulated. Specifically, the values of L _A , L _C , L _D , and L were fixed, and the value of L _B was changed in 10 patterns. And it is possible to suppress the temperature rise in the upper region on the inner surface of the tube portion, and to reduce the temperature difference between the temperature of the upper region and the temperature of the lower region on the inner surface of the tube portion. Whether or not is possible is determined by the following determination method.

As a determination method, the arc tube when “L _B / L _A = 1” is used as a comparative example (see FIG. 3), and the temperature T _B in the upper region on the inner surface of the bulb portion is the tube of the comparative example. When the temperature is lower than the temperature TB _′ of the upper region 32a on the inner surface of the bulb portion 30a and higher than the temperature TA _′ of the lower region 34a on the inner surface of the tube bulb portion 30a of the comparative example, that is, “TA _′ When satisfying <T _B <T _{B ′} ”, it is possible to suppress the temperature increase in the upper region on the inner surface of the tube portion, and the temperature and lower region of the upper region on the inner surface of the tube portion. It was determined that it was possible to reduce the temperature difference from the temperature (“◯” in Table 1). On the other hand, when “TA _′ <T _B <T _{B ′} ” is not satisfied, it is difficult to suppress the temperature increase in the upper region on the inner surface of the tube portion, and the upper side of the inner surface of the tube portion is difficult to suppress. It was determined that it was difficult to reduce the temperature difference between the temperature of the region and the temperature of the lower region (“×” in Table 1).

As a result, as shown in Table 1, when the value of “L _B / L _A ” was 1.25, 1.5, 1.75, 2, 2.25, it was determined as “◯”. Further, when the values of L _B / L _A were 0.25, 0.5, 0.75, and 2.5, it was determined as “x”. Accordingly, when the relationship of “1 <L _B / L _A <2.5” is satisfied, it is possible to suppress the temperature increase in the upper region on the inner surface of the tube portion, and the tube portion It was found that the temperature difference between the upper region temperature and the lower region temperature on the inner surface can be reduced.

  The arc tube, the light source device, and the projector according to the present invention have been described based on the above-described embodiments. However, the present invention is not limited to the above-described embodiments, and various aspects can be used without departing from the scope of the present invention. For example, the following modifications are possible.

(1) In the arc tube 20 according to the above-described embodiment, “L _A <L _B ” and “(L _C −L _A )> (L _D −L _B )”, and further “L _C = L _D = L Although the case where the tube portion is configured to satisfy the relationship of “/ 2” has been described as an example, the present invention is not limited to this. _"L A _{<L B"} and _{"(L C -L A)> (} L D -L B) " tube spherical portion so as to satisfy the relationship of only needs to be configured in a _{"L C} ≠ _{L D"} It may be “L _C , L _D ≠ L / 2”.

(2) the arc tube 20 according to the embodiment, as can be seen from FIG. 2 (b) and 3, the tube spherical portion so that the length of L _B without changing the length of L _A becomes longer Although configured, the present invention is not limited to this. The length of the _"L A _{<L B"} and _{"(L C -L A)> (} L D -L B) " relationship or order as long as it satisfies the, _{L B} to shorten the length of _{L A} the or those constituting the tube spherical portion so as not to change, that constitutes the tube spherical portion so that the length of L _B while shortening the length of L _a becomes longer within the scope of the present invention.

(3) In the light source device 110 according to the above-described embodiment, the secondary mirror is used as the reflecting means disposed in the arc tube. However, the present invention is not limited to this, and a reflecting film is used as the reflecting means. It is also preferable. Further, in the light source device 110 according to the above-described embodiment, the light source device in which the sub-mirror as the reflecting means is disposed on the arc tube is described as an example, but the present invention is not limited to this. The present invention can also be applied to a light source device in which a secondary mirror is not provided.

(4) In the light source device 110 according to the above embodiment, the ellipsoidal reflector is used as the reflector. However, the present invention is not limited to this, and it is also preferable to use a parabolic reflector. In this case, the concave lens may not be provided.

(5) In the projector 1000 according to the above embodiment, the lens integrator optical system including the lens array is used as the light uniformizing optical system. However, the present invention is not limited to this, and the rod including the rod member is used. An integrator optical system can also be preferably used.

(6) The projector 1000 according to the above embodiment is a transmissive projector, but the present invention is not limited to this. The present invention can also be applied to a reflection type projector. Here, “transmission type” means that an electro-optic modulation device as a light modulation means, such as a transmission type liquid crystal device, transmits light, and “reflection type” This means that an electro-optic modulation device as a light modulation means, such as a reflective liquid crystal device, is a type that reflects light. Even when the present invention is applied to a reflective projector, the same effect as that of a transmissive projector can be obtained.

(7) In the projector 1000 according to the embodiment, the projector using the three liquid crystal devices 400R, 400G, and 400B has been described as an example. However, the present invention is not limited to this, and one, two, The present invention can also be applied to a projector using one or four or more liquid crystal devices.

(8) In the projector 1000 according to the above-described embodiment, the liquid crystal device is used as the electro-optic modulation device, but the present invention is not limited to this. In general, the electro-optic modulation device may be any device that modulates incident light in accordance with image information, and a micromirror light modulation device or the like may be used. For example, a DMD (digital micromirror device) (trademark of TI) can be used as the micromirror light modulator.

(9) The present invention can be applied to a rear projection type projector that projects from a side opposite to the side that observes the projected image, even when applied to a front projection type projector that projects from the side that observes the projected image. Is also possible.

FIG. 3 is a top view schematically showing an optical system of the projector 1000 according to the embodiment. The figure shown in order to demonstrate the arc tube 20 and the light source device 110 which concern on embodiment. Sectional drawing which looked at the peripheral part of the bulb part 30a in the arc tube 20a which concerns on a comparative example from the side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Ellipsoidal reflector, 12 ... Opening part, 14 ... Reflection concave surface, 20, 20a ... Arc tube, 30, 30a ... Tube part, 32, 32a ... Upper area | region in the inner surface of a tube part, 33, 33a ... Tube Upper region on the outer surface of the sphere part, 34, 34a ... Lower region on the inner surface of the tube part, 35, 35a ... Lower region on the outer surface of the tube part, 36, 36a ... Upper tube in the tube part Wall, 38, 38a ... Lower tube wall in the bulb portion, 40, 40a, 50, 50a ... Sealing portion, 42, 42a, 52, 52a ... Electrode, 44, 44a, 54, 54a ... Metal foil, 46 , 56 ... lead wire, 60 ... secondary mirror, 62 ... aperture, 64 ... reflective concave surface, 90 ... concave lens, 100 ... illumination device, 110 ... light source device, 120 ... first lens array, 122 ... first small lens, 130 ... second lens array, 132 ... 2 small lenses, 140: polarization conversion element, 150: superposition lens, 200: color separation light guide optical system, 210, 220 ... dichroic mirror, 230, 240, 250 ... reflection mirror, 260 ... incident side lens, 270 ... relay lens , 300R, 300G, 300B ... condensing lens, 400R, 400G, 400B ... liquid crystal device, 500 ... cross dichroic prism, 600 ... projection optical system, 1000 ... projector, A ... lowest against gravity on the inner surface of the tube portion B: position on the inner side of the tube portion, the uppermost position with respect to gravity, C: position on the outer surface of the tube portion, and on the outer surface of the tube portion, D: on the outer surface of the tube portion uppermost a position with respect to gravity, L ... distance from the point C to the point D, L a _... distance from the point P to the point a, L B _... point B from the point P Distance, the distance from L C _... point P to the point C, the distance from the L D _... point P to the point D, OC ... illumination optical axis, an intermediate position of P ... a pair of electrodes, SCR ... screen

Claims (7)

A tube section containing a pair of electrodes arranged along the optical axis;
An arc tube comprising a pair of sealing portions extending on both sides of the bulb portion;
In the cross section of the tube portion when the arc tube is cut in a vertical virtual plane including the optical axis,
The intermediate position of the pair of electrodes is a point P,
A position that is the lowest side with respect to gravity on the inner surface of the tube portion is a point A,
A position which is the uppermost side with respect to gravity on the inner surface of the tube portion is a point B,
A position that is the lowest side with respect to gravity on the outer surface of the tube portion is a point C,
A position that is the uppermost position with respect to gravity on the outer surface of the tube portion is a point D,
The distance from the point P to the point A and L _A,
Let L _B be the distance from point P to point B.
Let L _C be the distance from point P to point C.
When the distance from the point P to the point D is L _D ,
An arc tube characterized by satisfying a relationship of “L _A <L _B ” and “(L _C -L _A )> (L _D -L _B )”. The arc tube of claim 1, wherein
An arc tube characterized in that “1 <L _B / L _A <2.5”. The arc tube according to claim 1 or 2,
A light source device comprising: a reflector disposed on one sealing portion side of the arc tube and having a reflective concave surface that reflects light from the arc tube toward an illuminated region side. The light source device according to claim 3.
The reflective concave surface of the reflector corrects and reflects the refraction when light radiated from the center of the tube portion through the tube wall of the tube portion is refracted by the tube wall. A light source device having a curved shape. The light source device according to claim 3 or 4,
A reflective concave surface that is disposed on the other sealing portion side of the arc tube so as to cover an outer surface of the tube portion to be illuminated, and reflects light from the bulb portion toward the bulb portion. A secondary mirror having
The reflection concave surface of the secondary mirror is configured to correct and reflect the refraction when light radiated from the center of the tube portion through the tube wall of the tube portion is refracted by the tube wall. A light source device characterized by having a curved surface shape. A light source device according to any one of claims 3 to 5,
An electro-optic modulator that modulates illumination light flux from the light source device according to image information;
A projector comprising: a projection optical system that projects light modulated by the electro-optic modulation device. The projector according to claim 6, wherein
A projector further comprising a cooling mechanism for cooling the light source device.

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