JP2002116501A - Illuminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such an illuminator that the size of a light source image formed on a 2nd fly-eye surface is made smaller like a point light source by much more improving the parallelism of luminous flux made incident on an integrator optical system. SOLUTION: Parallel beams reflected by a rotating parabolic mirror 4 are emitted toward the integrator optical system 5 through a window 14 formed of the non mirror surface of a plane mirror 12, while light emitted from a light source 3 and not entering the mirror 4 directly is reflected by the mirror 12 made orthogonal to the optical axis of the parallel beams, returned to the mirror 4 again and reflected thereby, and passes through a focal position and is reflected by the mirror 4 again so as to be emitted as the parallel beams, whereby almost all the luminous flux being the light source light is efficiently utilized, and also the parallelism of the luminous flux emitted toward the optical system 5 is not lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device suitable for illuminating a rectangular object such as a liquid crystal panel.

[0002]

2. Description of the Related Art As an illumination optical system for uniformly illuminating a rectangular projection object such as a liquid crystal panel, a conventional illumination optical system has been proposed.
An integrator optical system combining two sets of fly-eye lens arrays is known, for example, from JP-A-3-111806.

The integrator optical system disclosed in the publication discloses a first fly-eye lens array which receives a light beam from a light source having a reflector such as a parabolic reflector, an elliptical reflector, or a hyperboloid reflector. The secondary light source images are formed by being divided by a plurality of rectangular condensing lenses, and these secondary light source images are made to correspond to the plurality of rectangular condensing lenses of the first fly-eye lens array. This is configured to form a superimposed image on the same projection object via a second fly-eye lens array having a plurality of condenser lenses. According to such an integrator optical system, it is described that the utilization efficiency of the light from the light source is improved and the light intensity distribution on the surface of the projection target can be made substantially uniform. In particular, the shape of each condenser lens in the first fly-eye lens array is made to correspond to the aspect ratio of the rectangular projection object, for example, 4: 3
The use efficiency and the intensity distribution of light can be made uniform by forming a rectangular shape with a certain ratio.

That is, in Japanese Patent Laid-Open No. 3-111806, a macro lens array having a rectangular lens as a first lens and a second macro lens array having a lens corresponding to the first lens are used as an integrator optical system. , So that irradiation with an aspect ratio suitable for the object to be irradiated can be performed. According to FIG. 23 of the publication as a configuration example on the light source side, according to FIG. 23, a light source is placed at a first focal point of a spheroidal mirror, a collimator lens is placed after a second focal point, and then guided to an integrator optical system. Like that.

FIG. 7 shows an example of a configuration using a rotating parabolic mirror instead of the spheroidal mirror shown in FIG. 23 in JP-A-3-111806. In FIG. 7, basically, a macro lens array (first fly-eye lens) 101 having a rectangular lens as a first lens of an integrator optical system 100 and a second lens having a lens corresponding to the first lens The macro lens array (second fly-eye lens) 102 is used to perform irradiation with an aspect ratio suitable for the LCD 103 that is the irradiation object. As the light source side, the focal point F1 of the rotating parabolic mirror 104
Parabolic mirror 104 emitted from a light source 105 disposed in
The collimated lens 1 focuses the light collimated by the reflection by the convex lens 106 at a position corresponding to the second focal point F2.
07, the light is incident on the integrator optical system 00. In FIG. 7, reference numeral 108 denotes a polarization alignment prism array for aligning only the P-polarization component or only the S-polarization component with respect to the light source light in which the P-polarization component and the S-polarization component are mixed, and 109 and 110 denote lenses.

[0006] Although the number of parts is increased by one as compared with the example in the publication, the size of the reflector (collectively referred to as a rotating parabolic mirror, a spheroidal mirror, etc.) and the position of the focal point can be set freely.

According to Japanese Patent Application Laid-Open No. 10-16065, a light source is placed at the focal position of a parabolic mirror, parallel light is obtained, narrowed by a convex lens, returned to parallel light again by a concave lens, and then polarized. There has been proposed an illumination device for guiding to a conversion means or an integrator optical system.

FIG. 8 illustrates an illuminating device based on the concept of the example of Japanese Patent Application Laid-Open No. Hei 10-161665. FIG.
In contrast to the above, the collimating lens 111 is disposed closer to the light source side (the light source side) than the position corresponding to the second focal point F2, and the collimator lens 107 is omitted.

Further, as shown in FIG. 9, a light source 105 is provided at a first focal point F1 of a spheroidal mirror (rotating parabolic mirror 104) as in the case of the above-mentioned Japanese Patent Application Laid-Open No. 3-111806.
Is placed, the collimator lens 107 is placed after the second focal point F2, and then guided to the integrator optical system 100.
The luminous flux that does not enter the spheroidal mirror 104 is converted to the first focus F
The light source 105 is returned to the light source 105 by the concave mirror 112 of
Some have made available most of the light flux emanating from them.

[0010]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Laid-Open No. 3-11 / 1991.
The idea disclosed in Japanese Patent Publication No. 1806 is to reduce the size of the entire integrator optical system 100 by once condensing a light beam emitted from the light source 105 and to convert the light beam into parallel light by a collimator lens 107, thereby satisfying a global purpose. It is. However, in this configuration, the size of the light source image at the focal point where the luminous flux diverging from the light source 105 is collected again is magnified many times as large as the original light source image.
There is a limit in trying to make parallel light at 07, and the light use efficiency in the integrator optical system 100 is reduced. This property shows the same tendency as the combination of the paraboloid of revolution 104 and the convex lens 107 even when a spheroidal mirror is used instead of the paraboloid of revolution 104.

In addition, even if it is configured as disclosed in Japanese Patent Application Laid-Open No. H10-16065, the parallel light output from the parallelizing lens (concave lens) 111 is in principle the same as the parallel light obtained by the collimator lens 107 shown in FIG. Only about parallel light can be obtained. Also in this method, similarly to the above-described conventional example, this property is such that even if the parallelizing lens 111 is placed in front of the second focal point F2 using a spheroidal mirror,
It shows the same tendency as the combination of the lens 04 and the parallelizing lens 111.

Further, in the example shown in FIG. 9, the first focus F
By disposing the concave mirror 112 whose spherical center coincides with the position 1, the light that cannot be captured on the mirror surface of the rotating parabolic mirror 104 is used recursively, thereby improving the use efficiency of the luminous flux emitted from the light source 105. ing. However, the idea of once condensing the light flux and making it parallel light by the collimator lens 107 to reduce the size of the entire integrator optical system 100 and satisfy the global purpose is the same as the conventional example shown in FIG. Things. Therefore, in this configuration, the size of the light source image at the focal point where the luminous flux diverging from the light source 105 is collected again is multiplied by many times the original light source image. However, there is a limit, and there is no substitute for reducing the light use efficiency in the integrator optical system 100.

Accordingly, the present invention further reduces the size of a light source image formed on the second fly-eye lens surface of the integrator optical system to a point light source shape by further improving the parallelism of a light beam incident on the integrator optical system. It is an object of the present invention to provide a lighting device that can perform the lighting.

[0014]

According to the first aspect of the present invention,
A light source is provided near the focal point of the rotating parabolic mirror, and in a lighting device for emitting parallel light emitted from the light source and reflected by the rotating parabolic mirror toward an integrator optical system,
A plane mirror having a non-mirror surface window having substantially the same size as the outer size of the input section of the integrator optical system and having a light-transmitting property is disposed orthogonal to the optical axis of the parallel light.

Therefore, the parallel light basically reflected by the rotating parabolic mirror is emitted toward the integrator optical system through the non-mirror window of the plane mirror, while being emitted from the light source and directly directed to the rotating parabolic mirror. The light that does not enter is reflected by a plane mirror perpendicular to the optical axis of the parallel light, and is reflected back to the rotating parabolic mirror again. Since the light can be emitted, almost all of the light flux of the light source light can be used efficiently, and the parallelism of the light flux emitted toward the integrator optical system can be improved. Furthermore, since the size of the non-mirror surface window having the same size as the outer size of the input portion of the integrator optical system and having translucency can be restricted, the size of the integrator optical system can be reduced.

According to a second aspect of the present invention, in the lighting device of the first aspect, the plane mirror is provided integrally with a front glass provided at an outlet of the parabolic mirror.

Therefore, by providing the plane mirror integrally with the front glass provided at the exit of the paraboloid of revolution, the structure can be simplified and the precision can be maintained.

According to a third aspect of the present invention, in the lighting device according to the first aspect, the flat mirror is provided between a front glass provided at an outlet of the paraboloid of revolution and a light emitting portion of the light source. ing.

Therefore, in order to realize the first aspect of the present invention, the overall size can be further reduced.

According to a fourth aspect of the present invention, in the illumination device of the first aspect, the plane mirror is provided integrally with a first fly-eye lens or a corresponding member of the integrator optical system.

Therefore, by providing the plane mirror integrally with the first fly-eye lens or the corresponding member of the integrator optical system, the structure can be simplified and the accuracy can be maintained.

[0022]

FIG. 1 shows a first embodiment of the present invention.
It will be described based on.

The illuminating device A1 of this embodiment uses a rectangular liquid crystal panel 1 having a vertical and horizontal aspect ratio of 4: 3 as an object to be projected, and collects light for each liquid crystal element on the front surface. A condenser lens 2 for emitting light is provided. For such a liquid crystal panel 1, the illumination device A1 of the present embodiment includes a point light source 3, a rotating parabolic mirror 4 as a reflector in which the light source 3 is provided, and an integrator optical system. 5 and a condenser lens 6.

As the light source 3, an arc lamp such as a high-pressure mercury lamp, a metal halide lamp, and a xenon lamp is used. The light source 3 is disposed at the position of the focal point F of the rotating parabolic mirror 4 having a mirror surface 4a whose inner peripheral surface is formed by rotating the paraboloid. Therefore, the mirror surface 4 of the rotating parabolic mirror 4
“a” has an optical characteristic of emitting parallel light when receiving light from the light source 3. Such a rotating parabolic mirror 4
Is closed by a front glass 8.

The integrator optical system 5 is known, for example, from the above-mentioned Japanese Patent Application Laid-Open No. 3-111806, and is composed of a combination of a first fly-eye lens 9 and a second fly-eye lens 10. The two fly's eye lens 10 includes two cylindrical lens arrays 10a, 1
0b are arranged orthogonally. In the present embodiment, a polarization alignment prism array 11 in which a PBS (polarization beam splitter) array and a half-wave plate are combined is provided between the cylindrical lens arrays 10a and 10b, as is well known. I have. The condenser lens 6 arranged at the subsequent stage of the cylindrical lens array 10b plays a role of superimposing each light beam split by the fly-eye lens on the liquid crystal panel 1.

In the basic configuration of such a lighting device A, in the present embodiment, a plane mirror 12 is integrally provided using the inner side surface of the front glass 8 orthogonal to the optical axis of the parallel light beam. . The plane mirror 12 has a mirror surface formed on a part of the inner side surface of the front glass 8, and has a non-mirror surface window substantially the same size as the outer size of the first fly-eye lens 9 serving as an input portion of the integrator optical system 5. 13 is formed in the center. That is, the window 13 has a light transmitting property with respect to the light of the light source 3. An AR coat 14 for improving the light transmission efficiency is provided on the front glass 8 with respect to the window 13.

Therefore, in the illumination device A1 of this embodiment, the optical system including the collimator lens 107, the convex lens 106, the concave lens 111, and the like in the conventional example is omitted, and the reflector using the rotating parabolic mirror 4 is formed. The parallel light is directly input to the integrator optical system 5. However, since the entire light beam emitted from the light source 3 cannot be used by this alone, the light beam that is not directly input to the integrator optical system 5 is reflected by the plane mirror 12 arranged orthogonal to the optical axis of the parallel light generated by the rotating parabolic mirror 4. Return to the rotating parabolic mirror 4 again. The returned luminous flux is returned by the rotating parabolic mirror 4 to its focal point F, that is, the light emitting position of the light source 3. Here, in the present embodiment, an arc lamp such as a high-pressure mercury lamp, a metal halide lamp, or a xenon lamp is used as the light source 3, so that the returned luminous flux passes between the electrodes (actually, the focus made here is the light source And a part of the luminous flux is shielded by the electrode because it is slightly larger than the light source image generated when the light is first emitted.), And reaches the mirror surface 4a of the rotating parabolic mirror 4 again. After being reflected again, it becomes parallel light and travels from the window 13 to the integrator optical system 5.

Therefore, according to the present embodiment, basically, the parallel light reflected by the paraboloid of revolution 4 is emitted toward the integrator optical system 5 through the window 13 formed by the non-specular surface of the plane mirror 12, while Light emitted from the light source 3 and not directly entering the rotating parabolic mirror 4 is reflected by the plane mirror 12 perpendicular to the optical axis of the parallel light, and is returned to the rotating parabolic mirror 4 again to be focused. Since the light can be reflected again by the rotating parabolic mirror 4 and emitted as parallel light after passing through the F position, almost all of the light flux of the light from the light source can be used efficiently, and the light flux emitted toward the integrator optical system 5 can be used. Is not reduced. Furthermore, since the size of the non-mirror surface window 13 having substantially the same size as the outer size of the first fly-eye lens 9 located at the input portion of the integrator optical system 5 and having translucency can be regulated,
The size of the integrator optical system 5 can also be kept small, and the utilization rate of the luminous flux from the light source 3 can be maintained almost without being influenced by the shape of the integrator optical system 5. Further, by providing the plane mirror 12 integrally with the front glass 8 provided at the exit of the paraboloid of revolution 4, the configuration can be simplified and the accuracy such as the orthogonality can be maintained.

A second embodiment of the present invention will be described with reference to FIG. The same portions as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted (the same applies to each of the following embodiments).

In the first embodiment, the plane mirror 12 is integrally formed directly on the inner surface of the front glass 8. However, in the lighting device A2 of the present embodiment, the plane mirror 15 formed of a member different from the front glass 8 is used. 8 inner surface part (or outer part)
Are provided so as to be orthogonal to the optical axis of the parallel light beam.
The flat mirror 15 is made of, for example, a high-purity aluminum plate and its light source side surface is mirror-finished. In the center, a window 16 having the same shape as the outer shape of the first fly-eye lens 9 is formed.

It is clear that the same effect as in the first embodiment can be obtained by such a configuration.

In the lighting device A2 of the present embodiment,
Instead of the condenser lens 6, a convex lens 17 is provided substantially at the center between the cylindrical lens 10b and the liquid crystal panel 1. As in the case of the condenser lens 6, the convex lens 17 also has a function of superimposing the light beam split by the integrator optical system 5 on the surface of the liquid crystal panel 1.
In particular, as in the present embodiment, since the light beams generated by the respective constituent lenses of the fly-eye lenses 9 and 10 are parallel light from the convex lens 17 to the liquid crystal panel 1, the liquid crystal projector using the reflective liquid crystal panel. In the case of (1), it is possible to reduce the occurrence of color unevenness.

FIGS. 3 and 4 show a third embodiment of the present invention.
It will be described based on. In the present embodiment, only the configuration near the paraboloid of revolution 4 is shown. In the present embodiment, a plane mirror 15 made of a member different from the front glass 8 as shown in FIG. 2 is arranged between the front glass 8 and the light source 3.
That is, the plane mirror 15 is separated from the front glass 8 and closer to the light source 3 side. The size and shape of the window 15 are the same as those in FIG.

In such a configuration, the luminous flux emitted from the light source 3 is made substantially parallel by the rotating parabolic mirror 4, but generally includes a divergence angle of 5 to 10 °. Here, according to the configuration as in the present embodiment, since the light is emitted from the light source 3 and is returned by the plane mirror 15 before its divergence becomes large, the light source image formed at the focal point F position of the returned light flux in FIG. As compared with the case, the divergence angle after being reflected by the rotating parabolic mirror 4 and converted into parallel light again can be reduced, so that the drop in efficiency in the integrator optical system 5 can be suppressed. be able to. Further, according to the configuration of the present embodiment, as shown by the two-dot chain line (cuttable position) in FIG. The housing of the projector can be made thinner. The same processing can be performed not only on the upper and lower sides but also on the left and right sides. Further, instead of cutting, the outside of the two-point difference line may be box-shaped, and the housing can be similarly thinned.

FIGS. 5 and 6 show a fourth embodiment of the present invention.
It will be described based on. In the present embodiment, only the configuration near the paraboloid of revolution 4 is shown. In the present embodiment, the plane mirror 18 is provided integrally with the first fly-eye lens 9 located at the input section of the integrator optical system 5. More specifically, a substrate 19 of the same member of the first fly-eye lens 9 is formed to have a size capable of covering the opening of the paraboloid of revolution 4, and the lens portion of the first fly-eye lens 9 is defined as a window 20. , The periphery of which is a mirror surface.

According to the present embodiment, the structure in which the plane mirror 18 is provided can be simplified, and the number of adjustment points can be reduced, so that the cost can be reduced. In addition, a UV cut and an IR are provided between the integrator optical system 5 and the rotating parabolic mirror 4.
In the case of a configuration in which glass members such as cuts are placed, a similar effect can be obtained by leaving a light flux portion transmitting through the first fly-eye lens on these members and using the outside as a plane mirror.

[0037]

According to the illumination device of the first aspect of the present invention, the parallel light basically reflected by the paraboloid of revolution is emitted toward the integrator optical system through the non-mirror window of the plane mirror. The light emitted from the light source and not directly entering the rotating parabolic mirror is reflected by a plane mirror perpendicular to the optical axis of the parallel light, and then returned to the rotating parabolic mirror again to be reflected through the focal point position. Since it can be reflected again by the paraboloid of revolution and emitted as parallel light, almost all of the light flux of the light source light can be used efficiently, and the parallelism of the light flux emitted toward the integrator optical system is reduced. In addition, since the size of the non-mirror surface window having the same size as the outer size of the input portion of the integrator optical system and having translucency can be regulated, the size of the integrator optical system can be reduced. It is also possible to reduce the size small.

According to the second aspect of the present invention, in the lighting device of the first aspect, since the plane mirror is provided integrally with the front glass provided at the exit of the paraboloid of revolution, the configuration can be simplified. In addition, accuracy such as orthogonality can be maintained.

According to the third aspect of the present invention, in the lighting device according to the first aspect, the plane mirror is provided between the front glass provided at the exit of the rotating parabolic mirror and the light emitting portion of the light source. Therefore, in realizing the first aspect of the present invention, the overall size can be further reduced, and the light source light can be retroreflected by the plane mirror before the light diverges, so that the divergence angle is reduced. Can be suppressed.

[Brief description of the drawings]

FIG. 1 is an optical system configuration diagram showing a lighting device according to a first embodiment of the present invention.

FIG. 2 is an optical system configuration diagram showing a lighting device according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional structural view near a reflector showing a main part of a lighting device according to a third embodiment of the present invention.

FIG. 4 is a front view of the reflector.

FIG. 5 is a cross-sectional structural view showing a main part of a lighting device according to a fourth embodiment of the present invention, in the vicinity of a reflector.

FIG. 6 is a front view thereof.

FIG. 7 is an optical system configuration diagram showing a first conventional illumination device.

FIG. 8 is an optical system configuration diagram showing the vicinity of a reflector of the illumination device of the second conventional example.

FIG. 9 is an optical system configuration diagram showing the vicinity of a reflector of a third conventional illumination device.

[Explanation of symbols]

 Reference Signs List 1 Projected object, liquid crystal panel 3 Light source 4 Parabolic mirror, reflector 5 Integrator optical system, output light utilizing optical system 8 Front glass 9 First fly-eye lens 10 Second fly-eye lens 12 Plane mirror 13 Window 15 Plane mirror 16 Window 18 Plane mirror 20 windows

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Kameyama 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Kazuya Miyagaki 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Tadashi Honda 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Osamu Nagase Inside 109, Ohata 10th Land, 109, Ricoh Optical Co., Ltd. (72) Inventor Akihiro Yamakage 109, Ohata 10th Land, Hanamaki City, Iwate Prefecture Ricoh Optics Co., Ltd. 2H052 BA02 BA03 BA09 BA14 2H091 FA14Z FA21Z FA26Z FA41Z LA15 LA17 LA18

Claims (4)

[Claims] 1. A lighting device in which a light source is disposed near a focal point of a rotating parabolic mirror, and parallel light emitted from the light source and reflected by the rotating parabolic mirror is emitted toward an integrator optical system. A flat mirror formed with a non-mirror surface window having substantially the same size as the outer size of the input unit of the integrator optical system and having a light-transmitting property is disposed orthogonal to the optical axis of the parallel light. Lighting equipment. 2. The lighting device according to claim 1, wherein the plane mirror is provided integrally with a front glass provided at an outlet of the parabolic mirror. 3. The lighting device according to claim 1, wherein the plane mirror is provided between a front glass provided at an exit of the paraboloid of revolution and a light emitting unit of the light source. 4. The illumination device according to claim 1, wherein the plane mirror is provided integrally with a first fly-eye lens or a corresponding member of the integrator optical system.