JP4090094B2 - Light source device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light source device used as a light source device such as a liquid crystal projector. More specifically, the present invention relates to a high-intensity light source device including two light source lamps.
[0002]
[Prior art]
In a liquid crystal display device such as a liquid crystal projector, light emitted from a light source lamp composed of an arc lamp such as a metal halide lamp or a halogen lamp is applied to a light valve composed of a liquid crystal panel, and modulation corresponding to a display image is performed in the light bubble. After that, a projection image is formed on the projection surface via the projection optical system. Here, the liquid crystal light valve for modulating the light corresponding to the image information uses only a specific polarization component, and the polarization direction is different even if the liquid crystal light valve is irradiated with the light emitted from the light source lamp as it is. Half of the light component is not used. Therefore, in order to brighten the projected image, it is necessary to increase the luminance of the light source using a light source lamp having a high wattage.
[0003]
However, since there is an upper limit to the brightness of a single light source lamp, it is conceivable to realize a light source device with high brightness using two light source lamps. For example, Japanese Patent Laid-Open No. 6-265887 proposes an optical system in which the amount of light is increased by synthesizing outgoing light beams from two light source lamps via a multifocal lens.
[0004]
[Problems to be solved by the invention]
However, in a light source device in which two light source lamps are simply arranged in parallel, a multifocal lens, a condenser lens, etc. having a size including two circular emitted light beams emitted from each light source lamp are arranged, It is necessary to combine the two emitted light beams so as to be a single combined light beam. As a result, compared to the case of using a single light source lamp, the optical element to be used needs to have a large size, and the installation space for the optical system is correspondingly increased, and the light source device is increased in size. Of course, this also leads to high costs.
[0005]
Further, when attention is paid to the shape of the illumination target of the light source device, there are the following problems. That is, in the liquid crystal projector, the aspect ratio of the liquid crystal light valve is a horizontally long rectangle of 3: 4. Therefore, it is desirable that the shape of the exit light beam of the light source device that illuminates the light source, that is, the shape of the exit aperture of the light beam emitted from the light source device is also approximate to the shape of the illumination target. However, the shape of the exit aperture of the conventional light source device is generally circular, and when illuminated in such a state that a rectangular illumination target is included with such a circular exit light beam, the circular output light beam About 30% of the light is not used as illumination light. For this reason, the light utilization efficiency is poor.
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to make a light source device including two light source lamps and a combining optical system that combines the light beams emitted from these lamps and emits them as a single combined light beam, which can be configured in a compact, compact and inexpensive manner. There is in doing so.
[0007]
Moreover, the subject of this invention is improving the light utilization efficiency in the light source device provided with such two light source lamps.
[0008]
[Means for Solving the Problems]
A configuration of a polarized light source device according to the present invention will be described with reference to the drawings.
[0009]
FIG. 1 shows an optical system of a light source device according to the first aspect of the present invention. Referring to this figure, the light source device 1 includes first and second light source lamps 2 and 3, and first and second light sources emitted from the first and second light source lamps 2 and 3, respectively. It has a combining optical system 4 that combines the emitted light beams I (2) and I (3) and emits them as a single combined light beam I (out). In the figure, the cross-sectional shapes of the first and second outgoing light beams I (2), I (3), and the combined light beam I (out) are indicated by diagonal lines. The first and second light source lamps 2 and 3 can be configured to include arc tubes 2a and 3a and reflecting mirrors 2b and 3b.
[0010]
The first light source lamp 2 includes a first exit opening 2c through which a first emitted light beam exits, and a first shielding reflector 2d. The first shielding reflecting plate 2d shields the outer peripheral portion of the first emission opening 2c, and forms a first rectangular emission opening 2f centered on the light source optical axis 2e. In addition, the first shielding reflector 2d reflects the emitted light irradiated thereon. That is, the reflection surface is perpendicular to the light source optical axis 2e and is formed on the side facing the arc tube 2a.
[0011]
The second light source lamp 3 is similarly configured. That is, the second light source lamp 3 includes a second exit opening 3c through which the second emitted light beam exits, and a second shielding reflector 3d. The second shielding reflector 3d shields the outer peripheral portion of the second exit opening 3c to form a second rectangular exit opening 3f centered on the light source optical axis 3e. In addition, the second shielding reflector 3d reflects the emitted light irradiated thereto. That is, the reflection surface is perpendicular to the light source optical axis 3e and is formed on the side facing the arc tube 3a.
[0012]
Here, as shown in FIG. 1B, the first and second rectangular injection openings 2f and 3f are vertically long rectangles having the same shape. For example, the aspect ratio is 1: 0.5.
[0013]
On the other hand, the combining optical system 4 includes first and second reflecting plates 5 and 6 and a condenser lens 7.
[0014]
Next, the arrangement relationship of the above components will be described. First, the first and second light source lamps 2 and 3 are arranged facing each other so that the light source optical axes 2e and 3e are parallel to each other. In the example shown in the drawing, both light source optical axes are arranged to coincide with each other.
[0015]
Between these 1st and 2nd light source lamps 2 and 3, on the light source optical axis 2e of the 1st light source lamp 2, the 1st light source lamp 2 in the state in which the 1st reflecting plate 5 inclined 45 degree | times. It is arranged in a state where the reflecting surface faces to the side. On the other hand, on the light source optical axis 3e of the second light source lamp 3, the reflecting surface faces the second light source lamp side in a state where the second reflecting plate 6 is inclined 45 degrees in the reverse direction. Arranged in a state.
[0016]
A condenser lens 7 is disposed on the first and second reflecting plates 5 and 6 in the reflection direction, that is, on the side orthogonal to the light source optical axes 2e and 3e.
[0017]
The arc tubes 2a and 3a of the first and second light source lamps 2 and 3 are arc lamps or halogen lamps such as metal halide lamps. Further, as the reflecting mirrors 2b and 3b, those having an elliptical reflecting surface or a parabolic surface can be used.
[0018]
The operation of the light source device 1 configured as described above will be described. In the first light-emitting lamp 2, of the divergent light from the arc tube 2a, the intersection with the reflecting surface of the line segment perpendicular to the light source optical axis 2e drawn from the light emitting point P0 toward the reflecting surface of the reflecting mirror 2b All the light beams inside P1 pass through the first rectangular opening 2f centered on the light source optical axis 2e and are emitted as a light beam I (2) having a rectangular cross section.
[0019]
The light flux density of the light source lamp 2 has a distribution showing a high concentration in the central portion when viewed on a plane perpendicular to the central axis of the light flux. Therefore, by forming the first rectangular opening 2f with the optical axis of the light source as the center, it is possible to extract an outgoing light portion having a high luminous flux density, and the light use efficiency is high.
[0020]
Here, the distance from the light emitting point P0 of the arc tube 2a in the first light source lamp 2 to the reflecting surface of the reflecting mirror 2b when measured in the direction orthogonal to the light source optical axis 2e (the distance from the point P0 to the point P1). ) As a reference, it is desirable to set the length of the first rectangular injection opening 2f in the short side direction to twice that length. In this way, light from the light emitting tube 2a emitted on the outer peripheral side than the reflection point P1 (a) the reflection of after being reflected by the reflecting surface of the first shielding reflector 2d, again reflecting mirror 2b The light is reflected once or a plurality of times on the surface and is all emitted from the rectangular exit opening 2f. In other words, it is possible to substantially zero reflector 2b and the optical component that is not utilized as reflected by the outgoing light repeatedly between the reflecting surface of the first shielding reflector 2d. As a result, the light utilization efficiency can be further enhanced.
[0021]
Similarly, the second light source lamp 3 emits the emission light I (3) having a rectangular cross section through the second rectangular emission opening 3f.
[0022]
The traveling direction of the first outgoing light I (2) from the first light source lamp 2 is changed to a right angle by the first reflecting plate 5 and travels toward the condenser lens 7 arranged on the lower side in the drawing. To do. Similarly, the second outgoing light I (3) from the second light source lamp 3 is directed to the condenser lens 7 after the traveling direction is bent at a right angle by the second reflecting plate 6. The first and second emission lights I (2) and I (3) are emitted as a single combined light beam I (out) having a rectangular cross section through the condenser lens 7.
[0023]
Here, when the light source device 1 configured as described above is used as a light source of a liquid crystal projector, the aspect ratio of the illumination area of the liquid crystal light valve to be illuminated is a horizontally long rectangle of 3: 4. It is desirable that the first and second rectangular exit openings 2f and 3f of the light source device 1 have the following shapes. That is, it is desirable that the aspect ratio of the first and second injection rectangular openings 2f and 3f be a value within the range of 1: 0.5 to 1: 0.7. In this way, the cross-sectional shape of the combined light beam I (out) obtained through the combining optical system 4 is a horizontally long rectangle having an aspect ratio in the range of 1: 1 to 1: 1.4, and is almost illuminated. It matches the shape of the illumination area of the target liquid crystal light valve. As a result, the utilization efficiency of the emitted combined light beam I (out) can be increased.
[0024]
2 and 3 show modifications of the light source device 1 described above. The light source device 20 shown in FIG. 2 is different from the light source device 1 in that a multifocal lens is disposed in order to make the central light amount and the peripheral light amount of emitted light uniform. That is, a first multifocal lens (fly eye lens) 8 a is disposed between the first rectangular exit opening 2 f and the first reflector 5, and the second rectangular exit opening 3 f and the second reflector 6 are arranged. A configuration is adopted in which the second multifocal lens 8 b is disposed between them, and the third multifocal lens 9 is disposed in front of the condenser lens 7. Other configurations are the same as those of the light source device 1.
[0025]
3 has a configuration in which a polarization conversion optical system is further added to the light source device 20. By arranging the polarization conversion optical system 10, the emitted light beam I (out) can be emitted as a polarized light beam having a uniform polarization direction. Therefore, when it is used as a light source such as a liquid crystal projector, the light use efficiency is improved. Can be increased.
[0026]
Next, FIG. 4 shows an optical system of the light source device according to the invention of claim 4 of the present application. Referring to this figure, the light source device 40 includes first and second light source lamps 22 and 23 and first and second light sources emitted from the first and second light source lamps 22 and 23, respectively. A combined optical system 24 that combines the emitted light beams I (22) and I (23) and emits them as a single combined light beam I (out) is provided. In the figure, the cross-sectional shapes of the first and second outgoing light beams I (22), I (23), and the combined light beam I (out) are indicated by hatching. The first and second light source lamps 22 and 23 may be configured to include arc tubes 22a and 23a and reflecting mirrors 22b and 23b having a curved surface shape such as an elliptical surface or a parabolic surface.
[0027]
The first light source lamp 22 includes an exit opening 22c for the emitted light beam I (22) and a first shielding reflector 22d, and the first shielding reflector 22d has the exit opening 22c having the opening shape. One half is shielded around one axis of symmetry, and the outgoing light to be emitted from the one side portion is reflected. In the illustrated example, the exit opening 22d is circular. In this case, the semicircular portion on one side of the exit opening 22d is shielded, and the exit beam I (22 having a semicircular cross section is formed only from the opposite semicircular exit opening 22f. ) Is injected.
[0028]
The second light source lamp 23 has the same configuration as that of the first light source lamp 22, and includes an exit opening 23c for the outgoing light beam I (23) and a second shielding reflector 23d, and this second shield. The reflection plate 23d shields the exit opening 23c on one side half around one symmetry axis of the opening shape, and reflects outgoing light to be emitted from the one side part. In the example shown in the figure, the exit opening 23d is circular, and therefore, the emitted light beam I (23) having a semicircular cross section is emitted only from the semicircular exit opening 23f on one side.
[0029]
In the present invention, the exit openings 22c and 23c of the first and second light source lamps 22 and 23 have the same shape, and are thus defined by the first and second shielding reflectors 22d and 23d. The semicircular injection openings 22f and 23f have the same shape. Furthermore, these semicircular injection openings 22f and 23f are set to be on the same side.
[0030]
The combining optical system 24 includes a first reflecting plate 25, a second reflecting plate 26, and a condenser lens 27.
[0031]
Next, the arrangement relationship of each component described above will be described. First, the first and second light source lamps 22 and 23 are arranged facing each other so that the light source optical axes 22e and 23e are parallel to each other. In the illustrated example, they face each other so that the light source optical axes coincide with each other.
[0032]
Between these 1st and 2nd light source lamps 22 and 23, on the light source optical axis 22e of the 1st light source lamp 22, the 1st light source lamp 22 in the state in which the 1st reflecting plate 25 inclined 45 degree | times. It is arranged in a state where the reflecting surface faces to the side. On the other hand, on the light source optical axis 23e of the second light source lamp 23, the reflecting surface faces the second light source lamp side in a state where the second reflecting plate 26 is inclined 45 degrees in the reverse direction. Arranged in a state.
[0033]
A condenser lens 27 is disposed on the reflection direction of the first and second reflectors 25 and 26, that is, on the side orthogonal to the light source optical axes 22e and 23e.
[0034]
The effect by the light source device 40 comprised in this way is demonstrated. First, part of the divergent light from the arc tube 22a of the first light source lamp 22 is directly applied to the reflecting mirror 22b, where it is reflected and emitted from the semicircular exit opening 22f. The remaining portion of the diverging light travels back through the diverging light path by the shielding reflector 22d that shields half of the emission opening 22d, reaches the reflecting mirror 22b, and is reflected and emitted from the semicircular emission opening 22f. . In this way, almost all of the divergent light from the arc tube 22a is emitted as an outgoing light beam I (22) having a semicircular cross section.
[0035]
Here, the reflecting mirror 22a reflects visible light and transmits infrared rays, it is desirable that a so-called cold mirror. In this way, the reflected light from the reflecting mirror 22a becomes a visible light band, and heat generation of the light source device can be suppressed.
[0036]
The emitted light beam I (22) having a semicircular cross section emitted from the first light source lamp 22 is reflected by the first reflecting plate 25 in a direction orthogonal to the condenser lens 27.
[0037]
On the other hand, the emitted light beam I (23) having a semicircular cross section is emitted from the second light source lamp 23 in the same manner, and secondly reflected by the reflecting plate 26 in the orthogonal direction toward the condenser lens 27.
[0038]
Since these semicircular outgoing light beams I (22) and I (23) are axisymmetric, after being combined through the condenser lens 27, they are emitted as a combined light beam I (out) having a single circular cross section. The The shape of the combined light beam is a shape corresponding to the circular exit openings 22c and 23c of each light source lamp.
[0039]
Here, FIG. 5 shows a modification of the light source device 40, and by arranging the multifocal lenses 28a, 28b and 29, the center light amount and the peripheral light amount of the emitted light beam are made uniform. .
[0040]
Next, FIG. 6 shows a light source device according to a fifth aspect of the present invention. The basic components of the light source device 60 are the same as those of the light source device 40 of FIG. The difference is that the first and second light source lamps 22 and 23 are arranged so that the light source optical axes 22e and 23e are orthogonal to each other, and accordingly, the second reflector 26 is not necessary. Is shown.
[0041]
In the light source device 60 having this configuration, the emitted light beam I (23) having a semicircular cross section from the second light source lamp 23 is directly directed to the condenser lens 27 as it is, and the first and second light beams are passed through the condenser lens 27. The combined luminous flux I (out) having a circular cross section formed by the outgoing luminous fluxes I (22) and I (23).
[0042]
FIG. 7 shows a modification of the light source device 60. This light source device 70 is provided with multifocal lenses 28a, 28b, and 29 to make the central light amount and the peripheral light amount of the emitted light beam uniform. It is.
[0043]
【The invention's effect】
As described above, according to the inventions according to claims 1 to 3 of the present application, the light source optical axis can be changed by partially shielding the exit openings of the first and second light source lamps with the shielding reflectors. A rectangular exit opening is formed at the center, and the outgoing light beams of rectangular cross-sections emitted from these are combined via a synthesis optical system to form a single combined light beam having a rectangular cross-sectional shape.
[0044]
Therefore, according to the present invention, since the emission light beam ga has a cross-sectional shape from each light source lamp, each optical element arranged on the emission side can be reduced, and the overall size and the size of the apparatus can be reduced. Price can be achieved.
[0045]
In addition, since a composite light beam having a rectangular cross-sectional shape can be formed, when used as a light source for a liquid crystal projector, a composite light beam that matches the illumination area of the liquid crystal light valve to be illuminated can be formed, thereby increasing the light utilization efficiency. Can do.
[0046]
Furthermore, since the rectangular exit aperture of each light source lamp is centered on the light source optical axis, it is possible to use the outgoing light portion having a high luminous flux density, and from this point, the light utilization efficiency can be enhanced.
[0047]
In addition, by appropriately setting the dimensions of the rectangular exit opening formed by the shielding reflector, it is possible to use substantially all of the divergent light from the arc tube of each light source lamp. The utilization efficiency can be further increased.
[0048]
According to the invention according to claim 4 or 5 of the present application, half of the exit openings of the first and second light source lamps are respectively shielded by the shielding reflector, and the emitted light beam is emitted from the unshielded side. Are combined through a combining optical system to obtain a combined light beam having a cross-sectional shape corresponding to the exit aperture of each lamp.
[0049]
Therefore, according to the present invention, since the optical element disposed on the emission side of each light source lamp may be half the size of the conventional one, it is possible to reduce the size and cost of the apparatus as a whole. Moreover, in each light source lamp, substantially all of the divergent light from the arc tube can be used as the outgoing light beam by the shielding reflector, so that the light utilization efficiency can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an optical system of a light source device to which the present invention is applied.
FIG. 2 is a schematic configuration diagram showing a modification of the light source device of FIG. 1;
3 is a schematic configuration diagram showing another modification of the light source device of FIG. 1. FIG.
FIG. 4 is a schematic configuration diagram showing an optical system of another light source device to which the present invention is applied.
FIG. 5 is a schematic configuration diagram illustrating a modification of the light source device of FIG. 4;
FIG. 6 is a schematic configuration diagram showing an optical system of still another light source device to which the present invention is applied.
7 is a schematic configuration diagram showing a modification of the light source device of FIG. 6. FIG.
[Explanation of symbols]
1, 20, 30, 40, 50, 60, 70 Light source device 2, 22 First light source lamp 3, 23 Second light source lamp 2a, 3a, 22a, 23a Arc tube 2b, 3b, 22b, 23b Reflector 2c 3c, 22c, 23c Ejection apertures 2d, 3d, 22d, 23d Shielding reflecting plates 2e, 3e, 22e, 23e Light source optical axis 2f, 3f Rectangular exit apertures 22f, 23f Semicircular exit apertures 4, 24 Synthesis optical system 5, 6, 25, 26 Reflector 7, 27 Condenser lens 10 Polarization conversion optical systems 28a, 28b, 29 Multifocal lenses I (2), I (22), I (3), I (23) Outgoing light beam I (out) Synthetic luminous flux

Claims (5)

A first and second light source lamp; and a combining optical system that combines the first emitted light beam from the first light source lamp and the second emitted light beam from the second light source lamp to emit as a synthesized light beam. In the light source device having
The first light source lamp includes a first exit opening from which the first emitted light beam exits, and a first shielding reflector, and the first shielding reflector is the first exit reflector. Shielding the outer periphery of the opening to form a first rectangular exit opening centered on the optical axis of the light source;
The second light source lamp includes a second exit opening from which the second emitted light beam exits, and a second shielding reflector, and the second shielding reflector is the second exit. Shielding the outer periphery of the opening to form a second rectangular exit opening centered on the optical axis of the light source;
The first and second rectangular injection openings have the same shape;
The synthetic optical system includes first and second reflectors and a condenser lens,
The first and second light source lamps are arranged facing each other so that the respective light source optical axes coincide with each other,
Between these first and second light source lamps, on the light source optical axis of the first light source lamp, the first reflecting plate is disposed to face each other in an inclined state of 45 degrees, and the second light source lamp On the light source optical axis, the second reflector is disposed oppositely in a state inclined 45 degrees in the reverse direction,
The first and second outgoing lights reflected by the first and second reflecting plates are emitted as a combined light beam having a single rectangular cross section through the condenser lens. Light source device. In claim 1,
The aspect ratio of the first and second rectangular openings is a value within a range of 1: 0.5 to 1: 0.7. In claim 1 or 2,
Based on the distance from the light emitting point of the arc tube in each of the first and second light source lamps to the reflecting surface of the reflecting mirror when measured in the direction orthogonal to the light source optical axis, the first and second light source lamps A light source device characterized in that the length of the rectangular exit opening in the short side direction is set to double. In the light source device that synthesizes the first and second light source lamps, the first emitted light beam from the first light source lamp, and the second emitted light beam from the second light source lamp to emit as a synthesized light beam,
The first light source lamp, the first and the injection opening a first emitted light beam is emitted, and a first shielding reflector, the first shielding reflector, said first injection The opening is shielded on one side half around one axis of symmetry of the opening shape,
The second light source lamp, the second injection opening a second emitted light beam is emitted, and a second shielding reflector, the second shielding reflector, the second injection The opening is shielded on one side half around one axis of symmetry of the opening shape,
The exit openings of the first and second light source lamps have the same shape,
It said first portion being shielded by a portion and the second shielding reflector is shielded by a shielding reflector has a same side,
The synthetic optical system includes a first reflector, a second reflector, and a condenser lens.
The first and second light source lamps are arranged facing each other so that the respective light source optical axes coincide with each other,
Between the first and second light source lamps, the first reflector is disposed opposite to the light path of the light emitted from the first light source lamp in a state inclined by 45 degrees with respect to the light source optical axis. And
On the optical path of the emitted light from the second light source lamp, the second reflecting plate is disposed oppositely in a state inclined at 45 degrees in the reverse direction, and reflected by the first and second reflecting plates. The light source device is characterized in that the first and second outgoing lights are emitted as a combined light flux through the condenser lens. In the light source device that synthesizes the first and second light source lamps, the first emitted light beam from the first light source lamp, and the second emitted light beam from the second light source lamp to emit as a synthesized light beam,
The first light source lamp, the first and the injection opening a first emitted light beam is emitted, and a first shielding reflector, the first shielding reflector, said first injection The opening is shielded on one side half around one axis of symmetry of the opening shape,
The second light source lamp, the second injection opening a second emitted light beam is emitted, and a second shielding reflector, the second shielding reflector, the second injection The opening is shielded on one side half around one axis of symmetry of the opening shape,
The exit openings of the first and second light source lamps have the same shape,
It said first portion being shielded by a portion and the second shielding reflector is shielded by a shielding reflector has a same side,
The synthetic optical system includes a reflector and a condenser lens,
The first and second light source lamps are arranged such that the light source optical axes are orthogonal to each other,
On the optical path of the first outgoing light from the first light source lamp, the reflecting plate is disposed oppositely in a state inclined by 45 degrees with respect to the light source optical axis,
The first emission light reflected by the reflector and the second emission light emitted from the second emission opening of the second light source lamp are emitted as a combined light beam through the condenser lens. A light source device characterized by that.

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