JP4400352B2 - Light source device and projector - Google Patents

Description

  The present invention relates to a light source device and a projector.

2. Description of the Related Art Conventionally, a projector that modulates a light beam emitted from a light source in accordance with image information and projects an enlarged optical image is used. Such projectors are used for presentations in meetings and the like together with personal computers. In recent years, in response to the need to watch movies on a large screen at home, such projectors are also used for home theater applications.
As a light source device of the projector, a light source device 100 as shown in FIG. 6 can be exemplified. The light source device 100 includes an arc tube (light source lamp) 101 having a pair of electrodes 111B, a reflector 102 that reflects a light beam from the arc tube 101, and a sub-reflecting mirror 103. The arc tube 101 is installed such that the center between the pair of electrodes 111B (center A1 of the arc image A) coincides with the first focal point F1 of the reflector 102 (see, for example, Patent Document 1).

JP 2002-244199 A (second to third page, FIG. 7)

In such a light source device 100, the reflector 102 and the sub-reflecting mirror 103 are arranged such that the outer peripheral edge of the reflecting surface of the reflector 102 and the outer peripheral edge of the reflecting surface of the sub-reflecting mirror 103 are the center (arc image) between the pair of electrodes 111B. It is possible to propose a method of arranging so as to coincide with a plane N passing through the center A1) of A.
However, when arranged in this way, there is a problem that the light flux is lost from between the reflector 102 and the sub-reflecting mirror 103.
That is, the arc image A of the arc tube 101 is not a point light source but has two bright spots formed near the ends of the pair of electrodes 111B. The center of the pair of electrodes 111B (the center A1 of the arc image A) of the arc tube 101 and the first focal point F1 of the reflector 102 are made to coincide with each other, and the outer peripheral edge of the reflecting surface of the reflector 102 and the reflecting surface of the sub-reflecting mirror 103 Of the electrode 111B on the reflector 102 side (in the vicinity of the bright spot) when the outer peripheral edge of the electrode is arranged so as to coincide with the plane N passing through the center between the pair of electrodes 111B (center A1 of the arc image A). The light flux P emitted from the light escapes from the gap between the reflector 102 and the sub-reflecting mirror 103.
In order to prevent the leakage of the light flux P, the reflecting surface of the reflector 102 and the reflecting surface of the sub-reflecting mirror 103 must be arranged so that the reflector 102 or the sub-reflecting mirror 103 is enlarged. There is a problem of end.

  The objective of this invention is providing the light source device and projector which can prevent the leakage of a light beam and can prevent the enlargement of a reflector or a subreflector.

A light source device of the present invention, the light emitting unit having a light emitting body that forms a pair of electrodes and the discharge space covers the electrodes for performing discharge light emission and the light emitting tube having a sealing portion provided at both ends of the light emitting portion And a reflector having a reflecting surface that emits the luminous flux emitted from the arc tube in a fixed direction, and a luminous flux emitted from the arc tube having a reflective surface arranged to face the reflective surface of the reflector. A light source device including a sub-reflecting mirror that reflects on the reflector, wherein an end portion of one of the pair of electrodes disposed on the reflector side and a first focal point of the reflector are approximately one. The outer peripheral edge of the reflecting surface of the reflector and the outer peripheral edge of the reflecting surface of the sub-reflecting mirror are located on a surface that passes through the end of the one electrode and is orthogonal to the central axis of the light beam emitted from the reflector. And the above The reflecting surface of the reflector is an aspherical surface that cancels out the lens effect that occurs when the light beam emitted by the discharge between the electrodes inside the light emitting portion passes through the light emitting portion main body of the arc tube once. reflective surface, the light beam emitted by the discharge between the light emitting portion inside the electrode, Ri aspheric der to offset the lens effect occurring when through twice light emitting body of the light emitting tube, the light emitting portion of the light emitting portion The center of the main body substantially coincides with the position of the end of the one electrode, and the inner surface forming the discharge space of the light emitting unit main body is an ellipsoid whose major axis is the direction along the pair of electrodes. There, the outer surface of the light emitting body is characterized substantially spherical der Rukoto.
Here, the reflecting surface of the reflector may be an aspheric surface in which the reflected light beam forms an image at the second focal point, or may be an aspheric surface in which the reflected light beam becomes parallel light. .

In the present invention, the end of one electrode (in the vicinity of the bright spot) disposed on the reflector side of the arc tube and the first focal point of the reflector are substantially coincided with each other, passed through the end of this one electrode, and from the reflector. The outer peripheral edge of the reflecting surface of the reflector and the outer peripheral edge of the reflecting surface of the sub-reflecting mirror are positioned on a surface orthogonal to the central axis of the emitted light beam. Therefore, there is no end of the electrode (near the bright spot) behind the outer peripheral edge of the reflector (opposite to the direction of emission of the light beam emitted from the reflector), and light is generated behind the outer peripheral edge of the reflector. Therefore, even if the outer peripheral edge of the reflecting surface of the reflector and the outer peripheral edge of the reflecting surface of the sub-reflecting mirror are substantially matched, the light beam does not escape from the gap between the reflector and the sub-reflecting mirror.
Therefore, it is not necessary to overlap the reflecting surface of the reflector and the reflecting surface of the sub-reflecting mirror, and the reflector or the sub-reflecting mirror can be prevented from being enlarged.

Further, since the light beam generated by the discharge reaches the reflecting surface of the reflector through the light emitting unit main body, the lens effect (refraction) by the light emitting unit main body is generated in the light beam reaching the reflector. In the present invention, the reflecting surface of the reflector is an aspherical surface that cancels out the lens effect (refraction) that occurs when the light beam passes through the light emitting portion main body of the arc tube once. Therefore, a light beam that is not affected by the lens effect can be emitted from the reflector.
For example, in the case of a reflector having a substantially elliptical reflecting surface, the light beam emitted from the arc tube is reflected by the reflecting surface of the reflector and is collected at the second focal point of the reflector, but passes through the light emitting unit body. Due to the lens effect, the image formed at the second focal point may be expanded or distorted.
In the present invention, when the reflecting surface of the reflector is the above-mentioned aspherical surface, the image formed at the second focal point of the reflector is assumed to have no light-emitting unit body (the luminous flux emitted by the discharge between the electrodes is When the light is directly reflected by the reflector, it substantially coincides with the image of the second focal point formed. Thereby, the expansion | swelling, distortion, etc. of the image in the 2nd focus by the lens effect of the light emission part main body can be prevented.

Furthermore, a part of the light beam generated by the discharge passes through the light emitting unit main body, is reflected by the sub-reflecting mirror, and is again introduced into the light emitting unit main body. Therefore, this light beam is affected by the lens effect that occurs when it passes through the light emitting unit main body twice. In contrast, in the present invention, the reflecting surface of the sub-reflecting mirror is an aspherical surface that cancels out the lens effect that occurs when the light beam passes through the light-emitting unit body twice. The light beam introduced into is a light beam not affected by the lens effect.
Here, “the light beam emitted by the discharge between the electrodes inside the light emitting part is an aspherical surface that cancels out the lens effect that occurs when the light emitting part main body of the arc tube passes twice” means that one electrode The light beam emitted from the end (near the bright spot) is reflected by the reflecting surface of the sub-reflecting mirror and returns toward the end (near the bright spot) of the other electrode.

In here, the optical axis of the light source device is the center axis of the light beam emitted from the reflector, the light emitting portion first quadrant the area formed by the line perpendicular to the optical axis of the street light source device the center of the body, The second quadrant, the third quadrant, and the fourth quadrant. Among these regions, the sub-reflecting mirrors are arranged so as to straddle the first quadrant and the third quadrant (for example, Q1 shown in FIG. 3 is the first quadrant, Q2 is the second quadrant, Q3 is the third quadrant, Q4 is the fourth quadrant, and reference numeral 13 is a sub-reflecting mirror).
When the light beam generated in the second quadrant and the light beam generated in the first quadrant are reflected by the reflecting surface of the sub-reflector in the first quadrant, the light beams having different behaviors are reflected by the sub-reflector. It will be. Therefore, there is a possibility that the aspheric shape of the reflecting surface of the sub-reflecting mirror becomes complicated.
On the other hand, in the present invention, the center of the light emitting unit main body of the light emitting unit and the end of the electrode on the reflector side are substantially matched, so that, for example, only the light beam generated in the first quadrant is within the first quadrant. It is reflected by the reflecting surface of the sub-reflecting mirror. Accordingly, it is possible to prevent complication of the aspheric shape of the reflecting surface of the sub-reflecting mirror.

The projector according to the present invention includes any one of the light source devices described above, a light modulation device that modulates a light beam from the light source device according to image information to form an optical image, and an optical image formed by the light modulation device. And a projection optical system for enlarging and projecting.
Since the projector of the present invention includes any one of the light source devices described above, the same effects as the light source device can be obtained. That is, leakage of the light beam can be prevented, and an increase in size of the reflector or the sub-reflecting mirror can be prevented.

[1. First embodiment]
[Projector configuration]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an optical system of a projector 1 equipped with a light source device according to the present invention.
The projector 1 is an optical device that modulates a light beam emitted from a light source according to image information, forms an optical image, and projects the enlarged image on a screen.
As shown in FIG. 1, the projector 1 includes a light source device 10, a uniform illumination optical system 20, a color separation optical system 30, a relay optical system 35, an optical device 40, and a projection optical system 60 as a projection optical device. The optical elements and the optical device 40 that are configured and constitute these optical systems 20 to 35 are positioned and adjusted and accommodated in the optical component housing 2 in which a predetermined illumination optical axis B is set.

The light source device 10 illuminates the optical device 40 by emitting light beams emitted from the light source lamp 11 in a certain direction. As will be described in detail later, the light source device 10 includes a light source lamp 11, a reflector 12, a sub-reflecting mirror 13, and a lamp housing that holds them, but includes a lamp housing that holds them. Is provided with a collimating concave lens 14. The collimating concave lens 14 may be integrated with the light source device 10 or may be a separate body.
The light beam emitted from the light source lamp 11 is emitted as convergent light by the reflector 12 with the emission direction aligned in front of the light source device 10, collimated by the collimating concave lens 14, and emitted to the uniform illumination optical system 20. The

The uniform illumination optical system 20 is an optical system that divides the light beam emitted from the light source device 10 into a plurality of partial light beams and uniformizes the in-plane illuminance of the illumination area. The uniform illumination optical system 20 includes a first lens array 21, a second lens array 22, a polarization conversion element 23, a superimposing lens 24, and a reflection mirror 25.
The first lens array 21 has a function as a light beam splitting optical element that splits a light beam emitted from the light source device 10 into a plurality of partial light beams, and is arranged in a matrix in a plane orthogonal to the illumination optical axis B. A plurality of small lenses are provided.
The second lens array 22 is an optical element that condenses a plurality of partial light beams divided by the first lens array 21 described above, and is matrixed in a plane orthogonal to the illumination optical axis B as in the first lens array 21. It has the structure provided with the several small lens arranged in a shape.

The polarization conversion element 23 is a polarization conversion element that aligns the polarization direction of each partial light beam divided by the first lens array 21 with linear polarization in substantially one direction.
Although not shown, the polarization conversion element 23 has a configuration in which polarization separation films and reflection films that are inclined with respect to the illumination optical axis B are alternately arranged. The polarization separation film transmits one polarized light beam among the P-polarized light beam and S-polarized light beam included in each partial light beam, and reflects the other polarized light beam. The reflected other polarized light beam is bent by the reflecting film and emitted in the direction of emission of the one polarized light beam, that is, the direction along the illumination optical axis B. Any of the emitted polarized light beams is polarized and converted by a phase difference plate provided on the light beam exit surface of the polarization conversion element 23, and the polarization directions of almost all the polarized light beams are aligned. By using such a polarization conversion element 23, it is possible to align the light beam emitted from the light source lamp 11 with a polarized light beam in substantially one direction, so that the utilization factor of the light source light used in the optical device 40 is improved. Can do.

The superimposing lens 24 condenses a plurality of partial light beams that have passed through the first lens array 21, the second lens array 22, and the polarization conversion element 23, and superimposes them on image forming regions of three liquid crystal panels (to be described later) of the optical device 40. This is an optical element.
The light beam emitted from the superimposing lens 24 is bent by the reflection mirror 25 and emitted to the color separation optical system 30.

The color separation optical system 30 includes two dichroic mirrors 31 and 32 and a reflection mirror 33, and a plurality of partial light beams emitted from the uniform illumination optical system 20 by the dichroic mirrors 31 and 32 are converted into red (R), It has a function of separating light of three colors, green (G) and blue (B).
The dichroic mirrors 31 and 32 are optical elements in which a wavelength selection film that reflects a light beam in a predetermined wavelength region and transmits a light beam in another wavelength region is formed on a substrate. The dichroic mirror 31 disposed in the front stage of the optical path is a mirror that transmits red light and reflects other color light. Further, the dichroic mirror 32 disposed at the rear stage of the optical path is a mirror that reflects green light and transmits blue light.

  The relay optical system 35 includes an incident side lens 36, a relay lens 38, and reflection mirrors 37 and 39, and has a function of guiding the blue light transmitted through the dichroic mirror 32 constituting the color separation optical system 30 to the optical device 40. Have. The reason why such a relay optical system 35 is provided in the optical path of the blue light is that the optical path length of the blue light is longer than the optical path lengths of the other color lights, so that the light use efficiency is reduced due to the divergence of light. It is for preventing. In this embodiment, since the optical path length of blue light is long, such a configuration is used. However, a configuration in which the optical path length of red light is increased and the relay optical system 35 is used for the optical path of red light is also conceivable.

  The red light separated by the dichroic mirror 31 described above is bent by the reflection mirror 33 and then supplied to the optical device 40 via the field lens 41. The green light separated by the dichroic mirror 32 is supplied to the optical device 40 through the field lens 41 as it is. Further, the blue light is condensed and bent by the lenses 36 and 38 and the reflection mirrors 37 and 39 constituting the relay optical system 35 and supplied to the optical device 40 via the field lens 41. Note that the field lens 41 provided at the front stage of the optical path of each color light of the optical device 40 is provided to convert each partial light beam emitted from the second lens array 22 into a light beam parallel to the illumination optical axis B. ing.

  The optical device 40 forms a color image by modulating an incident light beam according to image information. The optical device 40 includes liquid crystal panels 42R, 42G, and 42B as light modulation devices to be illuminated (a liquid crystal panel on the red light side is 42R, a liquid crystal panel on the green light side is 42G, and a liquid crystal panel on the blue light side is 42B. And a cross dichroic prism 43. An incident-side polarizing plate 44 is interposed between the field lens 41 and the liquid crystal panels 42R, 42G, and 42B. Although not shown, between the liquid crystal panels 42R, 42G, and 42B and the cross dichroic prism 43, the illustration is omitted. In this case, an exit side polarizing plate is interposed, and the incident side polarizing plate 44, the liquid crystal panels 42R, 42G, and 42B and the light exiting side polarizing plate modulate light of each color light incident thereon.

The liquid crystal panels 42R, 42G, and 42B are a pair of transparent glass substrates in which a liquid crystal that is an electro-optical material is hermetically sealed. For example, a polysilicon TFT is used as a switching element and is incident on the incident side according to a given image signal. The polarization direction of the polarized light beam emitted from the polarizing plate 44 is modulated.
The cross dichroic prism 43 is an optical element that forms a color image by synthesizing an optical image modulated for each color light emitted from the emission side polarizing plate. The cross dichroic prism 43 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. One of the substantially X-shaped dielectric multilayer films reflects red light, and the other dielectric multilayer film reflects blue light. These dielectric multilayer films cause red light and blue light to be reflected. The light is 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 43 is enlarged and projected by the projection optical system 60 to form a large screen image on a screen (not shown).

[Configuration of light source device]
The light source device 10 includes a light source lamp 11 as an arc tube, a reflector 12, and a sub-reflecting mirror 13.
Here, as the light source lamp 11, various light-emitting tubes that emit light with high luminance can be employed. For example, a metal halide lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, or the like can be employed.
As shown in FIG. 2, the light source lamp 11 includes a light emitting part 111 and sealing parts 112 extending on both sides of the light emitting part 111. The light emitting unit 111 includes a spherical light emitting unit main body 111A made of quartz glass, a pair of electrodes 111B disposed in the light emitting unit main body 111A, and mercury, a rare gas sealed in the light emitting unit main body 111A, And a small amount of halogen.

The light emitting unit main body 111A has an outer surface formed of a spherical surface, an inner surface formed of an elliptical surface, and an ellipsoidal discharge space formed therein. The inner surface of the light emitting unit main body 111A has a major axis direction along the pair of electrodes 111B.
The pair of electrodes 111B is for forming the arc image A. When a voltage is applied to the pair of electrodes 111B, a potential difference is generated between the electrodes 111B, a discharge is generated, and an arc image A is generated.
Of the pair of electrodes 111B, the position of the tip of the end 111B11 (the end facing the other electrode 111B2) of one electrode 111B1 disposed on the reflector 12 side coincides with the center 111A1 of the light emitting unit main body 111A. ing. That is, the center between the pair of electrodes 111B (the center A1 of the arc image A) is shifted from the center 111A1 of the light emitting unit main body 111A toward the sub-reflecting mirror 13 side.
Further, the position of the tip of the end 111B11 of the one electrode 111B1 substantially coincides with the first focal point F1 of the reflector 12.

The sealing part 112 includes a sealing part body 112A made of quartz glass extending from both sides of the light emitting part body 111A, and a metal foil made of molybdenum (not shown) sealed inside the sealing part body 112A. . The sealing portion main body 112A is formed integrally with the light emitting portion main body 111A.
Each of the above-described electrodes 111B (the end opposite to the opposite end of each electrode 111B) is inserted into each sealing body 112A, and one end of the metal foil is connected to the electrode 111B. Has been. The other end of the metal foil is connected to the lead wire. The lead wire extends to the outside of the light source lamp 11.

The reflector 12 is for emitting the light beam emitted from the light source lamp 11 in a certain direction and has an aspherical reflecting surface 121. The reflector 12 has a first focal point F1 and a second focal point (not shown), and the light flux from the light source lamp 11 installed at the first focal point F1 is condensed at the second focal point.
The reflecting surface 121 of the reflector 12 is a cold mirror that reflects visible light and transmits infrared light. The reflecting surface 121 is an aspherical surface that cancels the lens effect (refraction) that occurs when the light beam emitted by the discharge between the electrodes 111B of the light source lamp 11 passes through the light emitting unit main body 111A of the light source lamp 11 once.
Note that the positions of the first focal point F1 and the second focal point of the reflector 12 are determined by the shape of the paraxial region of the reflector 12. Therefore, the shape of the surface other than the paraxial region is redesigned according to the shape of the light emitting unit main body 111A, and the aspherical surface cancels out the lens effect that occurs when the light emitting unit main body 111A passes once. For example, the shape of the surface other than the paraxial region is a shape in which a plurality of elliptical surfaces having different ratios of the major axis and the minor axis are connected.
By assuming that the reflecting surface 121 has an aspherical shape as described above, it is assumed that the image formed at the second focal point of the reflector 12 does not have the light emitting unit main body 111A (the light flux emitted by the discharge between the electrodes 111B is When the light is directly reflected by the reflector 12, the second focal point image substantially coincides with the second focal point image. Thereby, the expansion | swelling, distortion, etc. of the image in the 2nd focus by the lens effect of the light emission part main body 111A can be prevented.
That is, the luminous flux emitted by the discharge between the electrodes 111B is affected by the lens effect (refraction) of the light emitter main body 111A when passing through the light emitter main body 111A, and the emission angle from the light emitter main body 111A is inclined. Become. This inclination is canceled out by the reflecting surface 121 to prevent image expansion and distortion at the second focal point due to the lens effect of the light emitting unit main body 111A.
Further, the outer peripheral edge of the reflecting surface 121 of the reflector 12 passes through the end of the end portion 111B11 of the electrode 111B1 and is the optical axis X of the light source device 10 that is the central axis of the light beam emitted from the reflector 12 (coincides with the illumination optical axis B) It is located on the surface M orthogonal to.

The sub-reflecting mirror 13 is a reflecting member that covers approximately half of the light emitting unit 111 of the light source lamp 11 on the front side in the light beam emission direction, and the inner surface is a reflecting surface 131 that reflects the light beam. Similar to the reflecting surface 121 of the reflector 12, the reflecting surface 131 is a cold mirror.
The reflecting surface 131 is an aspherical surface that cancels out the lens effect that occurs when the light beam emitted by the discharge between the electrodes 111B inside the light emitting unit passes through the light emitting unit main body 111A twice. For example, the reflecting surface 131 has a shape in which a plurality of ellipsoidal surfaces having different ratios of the major axis and the minor axis are connected.

In such a reflective surface 131, as shown in FIG. 3, among the electrodes 111B of the light emitting unit main body 111A, the light flux generated at the tip end (in the vicinity of the bright spot) of the end portion 111B11 of one electrode 111B1 is transmitted to the other electrode 111B2. Reflected toward the tip of the end 111B21 (near the bright spot). The light beam reflected by the reflecting surface 131 passes through the tip of the other electrode 111B2 111B21 (in the vicinity of the bright spot) and reaches the reflecting surface 121 of the reflector 12.
In addition, the light beam generated at the tip of the end 111B21 (near the bright spot) of the other electrode 111B2 is reflected by the reflecting surface 131 and reaches the reflecting surface 121 of the reflector 12 through the end 111B11 of the one electrode 111B1. .
Accordingly, in the sub-reflecting mirror 13 as described above, the reflecting surface 131 is an aspherical surface that cancels out the lens effect that occurs when the light beam passes through the light-emitting portion main body 111A twice, so that it is reflected by the sub-reflecting mirror 13 and emits light. The light beam introduced into the main part 111A is a light beam not affected by the lens effect.
Also, in FIG. 4, the light beam generated at the tip of the end 111B21 of the other electrode 111B2 among the electrodes 111B of the light emitting unit main body 111A is reflected by the reflecting surface 131 and passes through the end 111B11 of the one electrode 111B1. A simulation of how the light emitting unit main body 111A is emitted toward the twelve reflective surfaces 121 is shown.
Further, the outer peripheral edge of the reflecting surface 131 as described above is located on a surface M that passes through the tip of the end portion 111B11 of the electrode 111B1 and is orthogonal to the optical axis X of the light source device 10 (see FIG. 2).

Here, as shown in FIG. 3, a region formed by the optical axis X of the light source device 10 and a line Y passing through the center 111A1 of the light emitting unit main body 111A and orthogonal to the optical axis X of the light source device 10 is defined in the first quadrant. In the case of Q1, the second quadrant Q2, the third quadrant Q3, and the fourth quadrant Q4, the sub-reflecting mirror 13 is disposed so as to straddle the first quadrant Q1 and the third quadrant Q3.
When the light beam generated in the second quadrant Q2 and the light beam generated in the first quadrant Q1 reach the reflecting surface located in the first quadrant Q1 among the reflecting surfaces of the sub-reflecting mirror, light beams having different behaviors are generated. It is reflected by the sub-reflecting mirror 13. Therefore, the aspheric shape of the reflecting surface 131 of the sub-reflecting mirror 13 may be complicated.
On the other hand, in the present embodiment, the center 111A1 of the light emitting unit main body 111A and the end 111B11 of the electrode 111B1 on the reflector 12 side are substantially matched, so that the discharge light emission between the electrodes 111B is in the first quadrant Q1 and the third quadrant Q1. Since it occurs in the quadrant Q3, for example, only the light beam generated in the first quadrant Q1 is reflected by the reflecting surface 131 of the sub-reflecting mirror 13 in the first quadrant Q1. In other words, it is refracted by passing through the light emitting unit main body 111A from the second quadrant Q2 and the fourth quadrant Q4 as in the prior art, and is different from the light passing through the light emitting unit main body 111A from the first quadrant Q1 and the third quadrant Q3. There is no need to consider the light incident on the sub-reflecting mirror 13 at an angle. Accordingly, it is possible to prevent the aspherical shape of the reflecting surface 131 of the sub-reflecting mirror 13 from being complicated, and the aspherical surface of the reflecting surface 131 can be easily designed.

Further, in the present embodiment, the end 111B11 tip (near the bright spot) of the electrode 111B1 disposed on the reflector 12 side of the light source lamp 11 and the first focal point F1 of the reflector 12 are made to coincide with each other, and the end 111B11 of this electrode 111B1. The outer peripheral edge of the reflecting surface 121 of the reflector 12 and the outer peripheral edge of the reflecting surface 131 of the sub-reflecting mirror 13 are positioned on a surface M that passes through the tip and is orthogonal to the optical axis X of the light source device 10. Therefore, the tip of the end portion 111B11 of the electrode 111B1 (near the bright spot) is not behind the outer peripheral edge of the reflector 12 (the rear side of the light emission direction of the reflector 12), and light is generated behind the outer peripheral edge of the reflector 12. Therefore, even if the positions of the outer peripheral edge of the reflecting surface 121 of the reflector 12 and the outer peripheral edge of the reflecting surface 131 of the sub-reflecting mirror 13 in the optical axis X direction are substantially matched, the luminous flux is reflected by the reflector 12 and the sub-reflecting mirror 13. It will not come out of the gap.
Therefore, it is not necessary to overlap the reflecting surface 121 of the reflector 12 and the reflecting surface 131 of the sub-reflecting mirror 13, and the reflector 12 or the sub-reflecting mirror 13 can be prevented from being enlarged.

[2. Second embodiment]
Next, a second embodiment of the present invention will be described. In the following description, the same reference numerals are given to the same parts as those already described, and the description thereof is omitted.
FIG. 5 shows the light source device 50 of the present embodiment. The light source device 50 includes a light source lamp 51 as an arc tube, a reflector 52, and a sub-reflecting mirror 53.
The light source lamp 51 includes a light emitting unit 111 similar to the light source lamp 11 of the above embodiment, and sealing units 112 extending on both sides of the light emitting unit 111.
The light source lamp 51 is different from the light source lamp 11 of the above-described embodiment in that the light source lamp 51 is arranged so that the center A1 of the arc image A formed by the pair of electrodes 111B substantially coincides with the center 111A1 of the light emitting unit main body 111A. Yes. The light source lamp 51 of the present embodiment is a general light source lamp 51 in which the center between the electrodes 111B coincides with the center 111A1 of the light emitting unit main body 111A.
The tip of the end portion 111B11 of one electrode 111B1 is located closer to the reflector 52 than the center 111A1 of the light emitting portion main body 111A of the light emitting portion 111.
Of the pair of electrodes 111B, the position of the tip of the end 111B11 of one electrode 111B1 on the reflector 52 side coincides with the first focal point F1 of the reflector 52.

In the reflector 52, the outer peripheral edge of the reflecting surface 521 is located on a surface M that passes through the tip of the end portion 111B11 of the electrode 111B1 and is orthogonal to the optical axis X of the light source device 50.
The reflection surface 521 has an aspherical shape similar to the reflection surface 121 of the reflector 12 of the above embodiment. The reflecting surface 521 is an aspherical surface that cancels out the lens effect that occurs when the light-emitting portion main body 111A passes once.
By doing so, as in the first embodiment, it is possible to prevent image expansion, distortion, and the like at the second focal point due to the influence of the lens effect of the light emitting unit main body 111A.

The reflection surface 531 of the sub-reflecting mirror 53 has an outer peripheral edge located on a surface M passing through the tip of the end portion 111B11 of the electrode 111B1 and orthogonal to the optical axis X of the light source device 50.
As described above, in the embodiment, the end 111B11 of the electrode 111B1 substantially coincides with the center 111A1 of the light emitting unit main body 111A. However, in the present embodiment, the end 111B11 of the electrode 111B1 is emitted from the light emitting unit 111. Since the reflector body 52 is located closer to the reflector 52 than the center 111A1 of the main part 111A, the reflecting surface 531 of the sub-reflecting mirror 53 of this embodiment is larger than the reflecting surface 131 of the sub-reflecting mirror 13 of the above embodiment. ing.
The other points are the same as those of the sub-reflecting mirror 13, and the reflecting surface 531 of the present embodiment also has a lens effect that occurs when the luminous flux emitted by the discharge between the electrodes 111B inside the light emitting unit 111 passes through the light emitting unit main body twice. Is an aspherical surface that cancels out. Thereby, the light beam reflected by the sub-reflecting mirror 53 and introduced into the light emitting unit main body 111A becomes a light beam not affected by the lens effect.

Furthermore, in the second embodiment as described above, the end 111B11 tip (in the vicinity of the bright spot) of the electrode 111B1 disposed on the reflector 52 side and the first focus F1 of the reflector 52 are made to coincide with each other, and the end of the electrode 111B1 The outer peripheral edge of the reflecting surface 521 of the reflector 52 and the outer peripheral edge of the reflecting surface 531 of the sub-reflecting mirror 53 are positioned on a surface M passing through the tip of 111B11 and orthogonal to the optical axis X of the light source device 50. Accordingly, no light is generated from the rear side (the rear side in the light beam emission direction of the reflector 52) from the outer peripheral edge of the reflector 52. Therefore, the outer peripheral edge of the reflecting surface 521 of the reflector 52 and the reflecting surface 531 of the sub-reflecting mirror 53 are not affected. Even if the outer peripheral edges are substantially matched, the light beam does not escape from the gap between the reflector 52 and the sub-reflecting mirror 53. Therefore, it is not necessary to overlap the reflecting surface 521 of the reflector 52 and the reflecting surface 531 of the sub-reflecting mirror 53, and the reflector 52 or the sub-reflecting mirror 53 can be prevented from being enlarged.
Further, in the present embodiment, since the general light source lamp 51 in which the center position between the electrodes 111B and the center 111A1 of the light emitting unit main body 111A coincide can be used, the cost of the light source lamp 51 is reduced. can do.

It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in each of the embodiments described above, the reflectors 12 and 52 have the first focal point F1 and the second focal point. However, the present invention is not limited to this, and a single focal point may be used like a parabolic mirror. .
Further, in each of the above embodiments, the light source devices 10 and 50 of the present invention are mounted on the projector. However, the present invention is not limited to this, and the light source device of the present invention may be mounted on another optical device.
In each of the above embodiments, only the example of the projector 1 using the three liquid crystal panels 42R, 42G, and 42B has been described. However, the present invention can be applied to a projector using four or more liquid crystal panels.
Furthermore, in each of the above embodiments, only the example of the front type projector 1 that performs projection from the direction of observing the screen is given. However, the present invention is a rear type that projects from the opposite side to the direction of observing the screen. It can also be applied to a projector.

  The present invention can be used as a light source device for a projector, and also as a light source device for other optical devices.

1 is a schematic diagram showing an optical system of a projector according to a first embodiment of the present invention. The schematic diagram which shows the light source device of the said projector. The schematic diagram which shows the reflective state of the light beam in the sub-reflection mirror of the said light source device. The figure which shows the simulation of the reflective state of the light beam in the sub-reflecting mirror of the said light source device. The schematic diagram which shows the light source device concerning 2nd embodiment of this invention. The schematic diagram which shows the conventional light source device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Projector, 10 ... Light source device, 11 ... Light source lamp (arc tube), 12 ... Reflector, 13 ... Subreflector, 50 ... Light source device, 51 ... Light source lamp, 52 ... Reflector, 53 ... Subreflector, 111 ... Light emitting part, 111A1 ... center, 111A ... light emitting part body, 111B ... electrode, 111B1 ... electrode, 111B11 ... end, 111B2 ... electrode, 111B21 ... end, 112 ... sealing part, 121 ... reflecting surface, 131 ... reflecting surface 521 ... Reflection surface, 531 ... Reflection surface, F1 ... First focus, M ... surface

Claims (2)

An arc tube having a sealing portion provided in the pair of electrodes and both ends of the light emitting portion and said light emitting portion has a light emitting body that forms a discharge space covers the electrodes for performing discharge light emission,
A reflector having a reflecting surface that emits the light emitted from the arc tube in a uniform direction; and
A light source device comprising a sub-reflecting mirror that has a reflecting surface disposed opposite to the reflecting surface of the reflector and reflects a light beam emitted from the arc tube to the reflector;
Of the pair of electrodes, the end of one of the electrodes arranged on the reflector side and the first focal point of the reflector substantially coincide with each other,
The outer peripheral edge of the reflecting surface of the reflector and the outer peripheral edge of the reflecting surface of the sub-reflecting mirror are located on a surface that passes through the end of the one electrode and is orthogonal to the central axis of the light beam emitted from the reflector,
The reflecting surface of the reflector is an aspherical surface that cancels out the lens effect that occurs when the light beam emitted by the discharge between the electrodes inside the light emitting portion passes through the light emitting portion main body of the arc tube once.
The reflecting surface of the sub-reflecting mirror, the light beam emitted by the discharge between the light emitting portion inside the electrode, Ri aspheric der to offset the lens effect occurring when through twice light emitting body of the light emitting tube,
The center of the light emitting unit body of the light emitting unit and the position of the end of the one electrode are substantially coincident,
The inner surface forming the discharge space of the light emitting unit main body is an ellipsoid whose major axis is the direction along the pair of electrodes,
Outer surface of the light emitting body includes a light source and wherein a substantially spherical der Rukoto. A light source device according to claim 1 ;
A light modulation device that modulates a light beam from the light source device according to image information to form an optical image;
A projector comprising: a projection optical system that enlarges and projects an optical image formed by the light modulation device.

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