JP2002279823A - Lighting device and lighting system using spherical mirror, and lighting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device and lighting system with improved light utilizing efficiency, which shortens the spatial distance between a light source and a part to be irradiated, and eliminates an unevenness of illuminance. SOLUTION: The lighting system is composed of a lighting device 1, comprising a spherical mirror 3 formed by arranging a light reflection surface on the inner surface of a hemispherical surface, an arc lamp 2 of which, an approximate center of the gap between arc electrodes 6 is located at the center of the sphere of the spherical mirror 3, and a condenser 4 superposing and condensing the light generated by arc and reflected by the spherical mirror 3, and the light directly traveling from the arc; and a lens plate 12 having a plurality of elementary lenses 11 dividing a flux of light into a plurality of flux of lights, a convex lens 18 making the divided flux of lights superpose on an object to be lighted, and a set of cylindrical lens arrays 14, 17, perpendicular to each other, installed in order to form an image of arc formed by the lens plate 12 having a plurality of elementary lenses 11 on the object to be lighted together with the convex lens 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination device for illuminating an object by converging an optical beam emitted from a light source, and more specifically, to converge a light source and radiation emitted by the light source. The present invention relates to an illuminating device including a spherical mirror and a lens system arranged for converged radiation.

[0002]

2. Description of the Related Art Various types of illumination systems including a light source, a concave mirror, and a lens system are known. The example shown in FIG. 14 is a lighting system disclosed in Japanese Patent Application Laid-Open No. 3-111806. In the figure, the lighting system 10
In the case of 0, the light beam emitted from the light source 102 is reflected by the concave reflector 103, and is then converted into a parallel beam by the condenser lens 104. This parallel radiation is divided into sub-beams for each lens 113 using a first macro-lens array 114 composed of a plurality of rectangular lenses 113 arranged in a matrix (for example, 6 × 8). Then, each sub-beam is divided into a second macro lens array 1 arranged in a matrix corresponding to the first macro lens array 114.
An image is formed on each of the 16 lenses 117. Each lens 117
Forms an image of the light spot formed by each lens 113 of the corresponding first macro lens array 114 on the display panel 110. A lens 119 is arranged behind the second macro lens array 116 in order to superimpose these re-imaging light spots on the surface of the display panel 110.

The first and second macro lens arrays 114 and 116 have the same aspect ratio as that of the display panel 110 (hereinafter referred to as “aspect ratio”). Has a desired uniformity, and the illumination system has a high light collection efficiency.

[0004]

However, in addition to those shown in the above-mentioned examples, there are still problems to be improved in the lighting devices and lighting systems according to the prior art. First, if the concave mirror that is generally used to reflect the light emitted from the light source is a parabolic mirror or a spheroidal mirror, it is reasonably efficient in using the reflected light,
The luminous flux emitted directly to the front is not effectively used. For this reason, only about 60 to 70% of the total luminous flux emitted by the lamp is used. That is, in the prior art, a technique for more efficiently irradiating the light from the light source to the projection target has been desired.

When a light source such as a filament that is impermeable to light is used as the light source, the reflected light is not transmitted even if a spherical mirror is used as the concave mirror for reflecting the radiated light. When an image is formed on a light source of an intense nature, the light source itself blocks the reflected light beam. In order to avoid this, it is necessary to dispose the light source at a slight offset from the spherical center of the spherical mirror, so that the emitted light is focused at one point (spherical center).
However, it was not possible to converge on the irradiation efficiency, and the irradiation efficiency was reduced.

Next, in the case of both a parabolic mirror and a spheroidal mirror, if the distance between the focal point and the reflecting surface is too small, the reflecting film is deteriorated by heat and the reflection efficiency is reduced. Become. For this reason, a certain gap is required between the two. However, if this gap is widened, the opening of the reflection surface becomes large, which makes it difficult to reduce the size, particularly the thickness, of the housing. Therefore, there has been a demand for a technique for reducing the diameter of the projection lens and reducing the size of the housing of the lighting device.

Further, the concave mirror according to the prior art, whether it is a parabolic mirror or a spheroidal mirror, has a large difference in luminous flux density near the center of the aperture and in the peripheral portion, and causes uneven illuminance on the screen. Was causing it to occur. Further, it is difficult to reduce the uneven illuminance on the screen because the burden on the integrator increases.

Accordingly, it is an object of the present invention to provide a lighting device and a lighting system with improved light use efficiency. In addition, the present invention reduces the spatial distance of the irradiated portion from the light source to obtain a smaller illumination device, and by reducing the aperture of the irradiation lens,
It is an object of the present invention to obtain a smaller illumination device and to provide an illumination device and an illumination system capable of eliminating uneven illuminance on a screen.

The present invention can be applied to a wide range of technical fields as an illumination device for illuminating an object, for example, an illumination system such as a liquid crystal projector, an overhead projector, and a slide projector.

[0010]

According to the present invention, a concave mirror for reflecting divergent light is formed as a spherical mirror which is a part of a spherical surface, and a center of a gap between arc electrodes of an arc lamp is arranged at a spherical center of the spherical mirror. This improves the irradiation efficiency of the lighting device, and specifically includes the following contents.

That is, according to the present invention, there is provided an arc lamp comprising a concave mirror having a light reflecting surface and a pair of arc electrodes, wherein an arc is generated between the two arc electrodes to emit divergent light. And a condensing device for condensing light rays reflected by the concave mirror after being radiated from the arc lamp, wherein the concave mirror has a hemispherical surface or an inner surface of a spherical shape smaller than a hemisphere. A spherical mirror having a light reflecting surface formed thereon, and the spherical center of the spherical mirror,
By arranging the center of the gap between the pair of arc electrodes of the arc lamp substantially coincident with each other, the light beam diverging from the arc and reflected by the spherical mirror is superimposed on the direct light diverging from the arc. The present invention relates to a lighting device that emits light to a light collecting device. By making the center of the arc lamp substantially coincide with the center of the arc lamp, the irradiation efficiency is improved.

The illumination device according to the second aspect of the present invention is characterized in that the light condensing device is constituted by an aspherical convex lens. The light collecting device is implemented with a simple configuration.

According to a third aspect of the present invention, in the illuminating device according to the present invention, the light collecting device is constituted by a plurality of convex lenses. By dividing the lens into a plurality of convex lenses, the load on each lens is reduced.

According to a fourth aspect of the present invention, in the illuminating device according to the present invention, the light condensing device is constituted by a plurality of convex lenses and at least one concave lens, and a light amount per unit area is set to a value near the center of the main optical axis. The power of the plurality of convex lenses and the power of at least one concave lens are adjusted so that the light is substantially uniform at the peripheral portion or the light amount at the peripheral portion is smaller than at the central portion.

According to a fifth aspect of the present invention, in the lighting device, one of the lenses constituting a part of the light collecting device also serves as a hood for preventing the arc lamp from scattering.

According to a sixth aspect of the present invention, the spherical mirror is formed by coating a light reflecting film on a hemispherical surface of a hollow sphere made of a transparent material, and the remaining hemispherical surface of the hollow sphere is formed. Form a hood for preventing the arc lamp from scattering. The spherical mirror and the hood are configured by effectively utilizing the hollow sphere.

According to a seventh aspect of the present invention, in the illuminating device according to the present invention, the hood formed by the hemispherical surface of the hollow sphere has a position intersecting with a main optical axis of a light beam reflected from the spherical mirror and its periphery. It is characterized in that it is formed in a flat shape close to the center of the hollow sphere. This is to reduce the length of the optical axis between the lighting device and the object to be illuminated.

The lighting device according to the present invention is characterized in that the hood also serves as one of the convex lenses constituting a part of the light collecting device. The length of the optical axis between the lighting device and the object to be illuminated is further reduced.

According to a ninth aspect of the present invention, in the illuminating device according to the present invention, the light reflecting film of the spherical mirror transmits one or both of ultraviolet light and infrared light and reflects at least light in a visible light region. It is characterized in that it is configured as a surface. The object to be illuminated is prevented from deteriorating by reflecting visible light around the center.

According to a tenth aspect of the present invention, the lighting device according to any one of the first to ninth aspects is configured to emit a light beam toward a set of integrators. The present invention relates to a lighting system characterized by the following. This realizes a system with high irradiation efficiency.

According to a twelfth aspect of the present invention, an illuminating device comprising a plurality of the illuminating devices according to any one of the first to ninth aspects emits a light beam toward a set of integrators. The present invention relates to a lighting system characterized in that: This realizes a system with high irradiation efficiency.

According to a twelfth aspect of the present invention, the illumination system according to the present invention further includes a polarizing function of aligning random light of the arc diverging from the arc lamp with one of P-polarized light and S-polarized light. It is characterized by.
This makes it possible to impart necessary polarized light to the irradiation light beam according to the purpose of use.

The illumination system according to the present invention is characterized in that the polarization function comprises a polarization alignment prism array.

The illumination system according to the present invention is characterized in that the polarization function is constituted by two polarization conversion prisms.

According to a fifteenth aspect of the present invention, a spherical mirror in which a light reflecting surface is formed on the inner surface of a hemisphere or a hemisphere or less, and the center of a gap between a pair of arc electrodes is arranged at the spherical center of the spherical mirror. An illumination device comprising an arc lamp, a light condensing device for superimposing and converging a light beam reflected by the spherical mirror on the divergent light generated from the arc lamp and a direct light divergent from the arc, and the one light beam A lens plate having a plurality of element lenses similar in shape to the screen to be illuminated, a convex lens for superimposing each of the divided luminous fluxes on the illumination target, and the plurality of element lenses. A set of cylindrical lens arrays orthogonal to each other to form an arc image created by a lens plate having the convex lens together with the convex lens on an object to be illuminated. An illumination system according to claim Rukoto. An object of the present invention is to provide a lighting system with high irradiation efficiency.

According to a twelfth aspect of the present invention, in the illumination system according to the first aspect, the illumination system aligns the random light generated by the arc lamp with one of S-polarized light and P-polarized light. It is characterized by further including a polarization function of irradiating light. This makes it possible to impart necessary polarized light to the irradiation light beam according to the purpose of use.

According to the present invention, there is provided an illumination method for reflecting a light beam diverged from an arc lamp with a concave mirror and condensing the reflected light beam to illuminate an object to be illuminated. Wherein the concave mirror is constituted by a spherical mirror in which a light reflecting surface is formed on the inner surface of a hemisphere or a hemisphere or less, and the spherical center of the spherical mirror substantially coincides with the center of the gap between the electrodes for generating the arc. Accordingly, the present invention relates to an illumination method characterized in that light rays diverging from the arc and reflected by the spherical mirror and direct light diverging from the arc are overlapped and condensed. It is an object of the present invention to provide an illumination method that can improve irradiation efficiency with a simple structure.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A lighting device according to a first embodiment of the present invention will be described with reference to the drawings. Hereinafter, the same reference numerals are used for the same components including the other embodiments. FIG. 1 shows an illumination device 1 according to the present embodiment in which an arc lamp 2 typified by a high-pressure mercury lamp or a metal halide lamp is used as a light source, and a light beam generated from the arc lamp 2 can be effectively applied to an illumination target. The basic principle of is shown. FIG. 1A is a side view of the lighting device 1, and FIG. 1B is a front view of the same.

In both figures, an illumination device 1 includes an arc lamp 2 serving as a light source, a hemispherical spherical mirror 3 arranged such that the arc lamp 2 is located at a spherical center, and a spherical mirror 3 with respect to the arc lamp 2. And an aspheric convex lens 4 which is a condensing device disposed on the opposite side. In addition, the spherical mirror 3 here includes not only a case where the mirror surface reflecting the light source is a hemisphere, but also a case where the mirror surface is a hemisphere or less.

Generally, the arc lamp 2 is used horizontally. Therefore, as shown in FIG. 1 (b), the spherical mirror 3 is arranged such that the center of the gap between the two electrodes 6 of the arc is almost at the spherical center C, and the arc lamp 2 is extended in a state where both the electrodes 6 extend horizontally right and left. Are arranged right beside. However,
As long as the center between the spherical center C of the spherical mirror 3 and the two arc electrodes 6 of the arc lamp 2 substantially coincides with each other, the spherical mirror 3 may be arranged in any rotation. For example, there is no problem even if it is upward, downward, or inclined at 45 ° or any angle.

As shown in FIGS. 1 (a) and 1 (b), if the focal point of the aspherical convex lens 4 is disposed so as to overlap the spherical center C of the spherical mirror 3, parallel light can be obtained about its main optical axis. Can be. That is, of the light generated at the spherical center C, the spherical mirror 3
In the direction toward the side, light traveling in any direction of the solid angle of 180 ° is reflected by the reflection surface of the spherical mirror 3, and then passes through the spherical center C toward the aspheric convex lens 4. On the other hand, of the light generated at the spherical center C, the light that directly goes to the aspherical convex lens 4 follows the same optical path as the reflected light, and
Reach

As described above, in principle, all the light generated at the spherical center C passes through the aspherical convex lens 4 and can be used as parallel light thereafter. In practice, Figure 1
The glass tube 7 for supporting the electrode of the arc lamp 2 shown in FIG. 2B becomes a shadow, and the aspherical convex lens 4 has a limit of covering a solid angle of about 160 °. . However, the loss can be significantly reduced by discarding the light radiated directly from the aperture, such as a parabolic mirror or a spheroid mirror according to the prior art.

In the recent arc lamp 2, the distance between the electrodes 6 is very short, and the distance between the electrodes 6 is usually less than 2 mm.
Furthermore, it is about 1 mm. In any case, as long as there is a gap between the electrodes 6 of the arc lamp 2, by arranging the center of the gap substantially at the spherical center C of the spherical mirror 3, the arc lamp 2 becomes transparent to its own reflected light. That is, the arc generated by the arc lamp 2 is
Is emitted at the spherical center C, and the emitted light from the generated arc is reflected by the spherical mirror 3 and then converges on the spherical center C.
Since the spherical center C forms a gap between the electrodes 6, all of the reflected light thereafter goes to the aspherical convex lens 4.

As the distance between the electrodes 6 becomes shorter,
The size of the arc image is also reduced to about 1 to 1.5 mm. Therefore, although the effects of arc fluctuations and uneven distribution are becoming smaller, the effects of arc fluctuations and uneven distribution cannot be essentially eliminated in the conventional parabolic mirror and spheroidal mirror. That is, a temporal change in the arc generation position appears as a temporal change in illuminance unevenness on the illumination target.

According to the configuration of the present embodiment, for example, as shown in FIG. 1A, even if an arc is generated at an upper position a off the center of the electrode (in fact, such a phenomenon Is generated in many cases), and the reflected light reflected back by the spherical mirror 3 returns to the spherical center C at the arc generation position a.
An image is formed at a position a ′ that is symmetric with respect to. Therefore, it is apparently in the same state that there is a double arc near the ball center C. Thus, by using the spherical mirror 3 and making the center of the arc lamp 2 (that is, the center of the gap between the two electrodes 6) substantially coincide with the spherical center C of the spherical mirror 3, the position of the arc is substantially shifted. However, the state is always the same as when the light source is located at a position centered on the spherical center C. As a result, even if the position of the arc fluctuates somewhat, it is possible to obtain an illuminance distribution that hardly changes over time on the illumination target.

FIG. 2 shows a first mode of a lighting system using the lighting apparatus 1 according to the present embodiment shown in FIGS. 1 (a) and 1 (b). In FIG. 2, after the parallel light is obtained by the spherical mirror 3 and the aspherical convex lens 4 as described above, a liquid crystal display panel (hereinafter, referred to as “LCD”) 10 having an aspect ratio of 3: 4 to be illuminated. A lens plate (hereinafter, referred to as a “macro lens array”) 12 in which a plurality of similar element lenses (in this case, convex lenses) 11 are arranged horizontally and vertically (or in rows and columns) to form a single lens plate. Lay perpendicular to the axis.

The macrolens array 12 produces light beams equal in number to the element lenses 11, and a plurality of cylindrical lenses 13 corresponding to the horizontal or vertical of each element lens 11 of the macro lens array 12 are arranged near the focal point. A first cylindrical lens array 14 is provided.

Thereafter, a polarization alignment prism array 16 is arranged, but may be omitted if it is not necessary to align the polarization. This polarization alignment prism array 1
In the configuration of No. 6, an array of PBSs whose polarization separation plane is set at 45 ° is used for two cylindrical lenses 13 for one cylindrical lens 13.
S are arranged so as to correspond to each other, are arranged so as to have the same longitudinal direction as the cylindrical lens 13 of the first cylindrical lens array 14, and the 1 / 2λ plate 15 is placed on every other emission side of the PBS. With this configuration, either the P-polarized light or the S-polarized light can be extracted from the polarization alignment prism array 16. Which polarized light is to be obtained can be determined depending on whether the 1 / 2λ plate 15 placed at every other exit of the PBS is placed every odd number or every even number.

Thereafter, in a form orthogonal to the first cylindrical lens array 14, it corresponds to the horizontal or vertical direction of the macro lens array 12 (or vertically if the first cylindrical lens array 14 corresponds to the horizontal direction, A second cylindrical lens array 17 in which cylindrical lenses are arranged horizontally (if they correspond vertically) is arranged.

Finally, the optical axis of each light beam formed by each element lens 11 of the macro lens array 12 is set to be an LCD to be illuminated.
The condenser lens 18 whose focal length is set so as to be directed toward the center of 10 is placed, and each light beam generated by each element lens 11 is superimposed on the LCD 10 to be illuminated. A macro lens array 1 radiated from an arc lamp 2 serving as a light source, converted into parallel rays by an aspheric convex lens 4, and then disposed in the middle to converge on an LCD 10 to be irradiated.
2. The first cylindrical lens array 14, the polarization alignment prism array 16, the second cylindrical lens array 17, and the condenser lens 18 are collectively called an integrator 20. However, among them, the polarization alignment prism array 16 is an option installed when extracting polarized light as described above.

The condenser lens 19 is installed so that the light beam illuminating the LCD 10 can pass through an illumination lens (not shown) efficiently. By doing so, the surface of the LCD 10 to be illuminated can obtain uniform illuminance.

FIG. 3 uses the illumination device 1 according to the present embodiment shown in FIGS. 1A and 1B and uses a polarization conversion prism 21 instead of the polarization alignment prism array 16 shown in FIG.
2 shows a second mode of the illumination system according to the present embodiment in which two light beams are used to align random light into one polarized light beam. In the configuration shown in FIG. 3, the spherical mirror 3 and the aspherical convex lens 4
The polarized light is polarized by inserting the polarization conversion prism 21 immediately after the collimated light is generated by (1) and (2). Other configurations are the same as those described above. However, in this configuration, when the size of the spherical mirror 3 and the aspheric convex lens 4 is the same, the size of the integrator 20a for the configuration of the illumination device needs to be doubled as compared with the case shown in the first mode. Occurs.

FIG. 4 shows a third example of a lighting system using the lighting device 1 according to the present embodiment shown in FIGS. 1 (a) and 1 (b).
Is shown. This embodiment shows that the combination of the spherical mirror 3 and the aspherical convex lens 4 does not necessarily make the light parallel to the first embodiment.

That is, the output light of the aspherical convex lens 4 is not converted into parallel light but is converted into a certain amount of divergent light, and is divided into a plurality of light beams by the macro lens array 12. At this time, each of the divided optical axes diverges, but each element lens 11 of the macro lens array 12 is focused through the condenser lens 23 near the first cylindrical lens array 14. Is set to

At this time, the respective optical axes divided into a plurality of light beams by the macro lens array 12 are made parallel by the condenser lens 23 and are incident on the polarization alignment prism array 16. Subsequent steps are the same as in the first embodiment.

By configuring the integrator 20 in this manner, the focal length of the aspherical convex lens 4 can be easily set, and the thickness of the convex lens 4 can be reduced.

Next, a lighting device and a lighting system according to a second embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a plurality of illuminating devices 1 including the arc lamp 2, the spherical mirror 3, and the aspherical convex lens 4 shown in the first embodiment are used, and the illuminance of the irradiation target is approximately doubled or further increased. Things. The point that the center of the arc lamp 2 substantially coincides with the spherical center C of the spherical mirror 3 is the same as in the first embodiment. FIG. 5 shows a first mode of the lighting system according to the present embodiment.

The example shown in FIG.
In this method, the focus F is once focused, and the collimator lens 27 returns to the parallel light again. The functions after the integrator 20 are exactly the same as those in the first mode (see FIG. 2) in the first embodiment. In the example shown in FIG. 5, a case where two lighting devices 1 are used vertically is shown, but three lighting devices 1 may be arranged in an equilateral triangle, or four lighting devices 1 may be formed into a square. The same can be applied to the arrangement. Increasing the number naturally increases the illuminance.

FIG. 6 shows a second mode according to the present embodiment. In the example shown in FIG. 6, the parallel light obtained by the illuminating device 1 is arranged, and the integrator 20 is not directly focused. It is what leads to. Also in this case, as in the first embodiment, the number of lighting devices 1 may be three, four, or the like.

When a plurality of illumination devices 1 shown in FIG. 6 are used, by using the polarization conversion prism 21 shown in the second mode of the first embodiment (see FIG. 3), the horizontal or horizontal direction can be obtained. Since the vertical spread can be covered, the lighting system can be configured more efficiently than when only one lighting device 1 is used. FIGS. 7A to 7D show specific examples of the arrangement of the lighting device 1. FIG.
FIG. 7A shows an arrangement example in which two illumination devices 1 are vertically arranged, and FIG. 7B shows a polarization conversion prism 21 at that time.
2 shows the distribution of the emitted light beam formed after passing through. Two polarization conversion prisms 21 are provided in a direction perpendicular to the drawing.

FIG. 7C shows an example in which two lighting devices 1 are arranged side by side (perpendicularly to the drawing).
(D) shows the distribution of irradiation light rays formed after passing through the polarization conversion prism 21 at that time. FIG.
As is clear from both figures (b) and (d), regardless of whether the illuminating devices 1 are arranged vertically or horizontally, the front surface can be formed by appropriately arranging the polarization conversion prism 21 in any case. When viewed from above, the emitted light can be distributed in a square. Thereby, the compatibility with the optical system after the integrator 20 for converging the parallel rays can be improved.

Next, a lighting device and a lighting system according to a third embodiment of the present invention will be described with reference to the drawings. The illumination device according to the present embodiment is configured such that the aspheric convex lens 4 which is a light condensing device included in the illumination devices 1 according to the first and second embodiments includes a plurality of lenses. As described in each of the embodiments described above, both the radiation light directly radiated from the arc lamp 2 and the reflection light reflected by the spherical mirror 3 are converted into parallel rays by a single aspheric convex lens 4 or close to parallel rays. In order to form a light beam, it is difficult and difficult to shape the aspherical convex lens 4. In order to solve this problem, in the present embodiment, the aspherical convex lens 4 is divided into a plurality of lens groups. The fact that the spherical center C of the spherical mirror 3 substantially coincides with the center of the arc lamp 2 is the same as in the previous embodiments.

FIG. 8 shows a first mode of the lighting apparatus according to the present embodiment. In the figure, the lighting device 3 according to the present embodiment
In the case of 0, the first convex lens 31 and the second convex lens 32 are arranged at a position facing the spherical mirror 3 perpendicular to the main optical axis. The radiation beam emitted by the arc lamp 2 is directly or after being reflected by the spherical mirror 3, is once refracted by the first convex lens 31, and further becomes a parallel beam by the second convex lens 32. After becoming a parallel ray, integrator 2
Since the convergence by 0 is the same as in the lighting system according to the first embodiment (see FIG. 2), the display of the entire lighting system is omitted in the drawing. In the lighting device 30 according to the present embodiment, the first convex lens 31
Can also be used as a hood for the spherical mirror 3 depending on the design as described later.

FIG. 9 shows a second mode of the lighting apparatus according to the present embodiment. The example shown in FIG. 9 is intended to make the light flux density of the parallel light constant. In the figure, a first convex lens 35 and a concave lens 3 perpendicular to the main optical axis are provided at positions facing the spherical mirror 3 with respect to the arc lamp 2.
6, the second convex lenses 37 are arranged in this order. The radiation emitted by the arc lamp 2 is directly or after being reflected by the spherical mirror 3,
After passing through 6, 37, they become parallel rays.

In the parabolic mirror and the spheroid mirror according to the prior art, the light around the main optical axis has a high intensity but the peripheral intensity is extremely weak, and the integrator 20 compensates for this. . As can be seen from the basic principle of the present invention described with reference to FIG. 1, according to the structure of the lighting device according to the present invention, the light emitted from the arc lamp 2 is directly or the spherical mirror 3.
When parallel light is obtained by the aspheric convex lens 4 after being reflected by
Contrary to a parabolic mirror or a spheroidal mirror, the luminous flux density at the periphery increases. Integrator 20 to correct it
However, the light emitted from the element lenses 11 around the macro lens array 12 becomes stronger,
The intensity of the light having the largest incident angle to 10 becomes strong. This is not very desirable due to the characteristics of the LCD 10, such as lowering the light use efficiency of the LCD 10 and lowering the ON / OFF effect.

In order to solve this problem, as shown in FIG. 9, a concave lens 36 is provided between two convex lenses 35 and 37 in the condensing device including a plurality of lenses according to the present embodiment. By inserting the light, the density of the luminous flux in the peripheral portion is also diffused, and the density can be made similar to that in the central portion. Alternatively, if necessary, the degree of diffusion of the luminous flux density in the peripheral portion can be increased. As described above, by including at least one concave lens in the lens group forming the light collecting device, the above-described adverse effects can be reduced.

When the luminous flux densities of the central portion and the peripheral portion are set to be almost the same, the above-described integrator 20 is omitted, and the irradiation target (in this case, LC
D10) may be directly applied. Of course, the condenser lens 19 for adjusting to the screen of the irradiation countermeasure
(See FIG. 2) does not depart from the essence of the present embodiment.

Next, a lighting device according to a fourth embodiment of the present invention will be described with reference to the drawings. In general, if an arc lamp is simply attached to a spherical mirror, it is dangerous because the arc lamp may be damaged. In particular, when a high-pressure mercury lamp is used as an arc lamp, mercury may be scattered due to damage. The present embodiment provides a lighting device provided with a hood that can prevent scattering of arc lamp components such as glass and mercury even if the arc lamp is broken.

According to the prior art, a hemispherical hood having the same diameter as the spherical mirror may be provided at a position facing the spherical mirror with respect to the arc lamp. In this case, the lighting device has a spherical shape as a whole including the hood. FIG.
This shows a lighting device 40 having such a configuration, in which a hemispherical glass hood 41 is arranged on the front surface of the spherical mirror 3.

However, in the case of such a configuration,
It takes time and effort to manufacture and assemble the spherical mirror 3 and the hood 41 separately. In addition, since the lens is entirely spherical, it is difficult to design a lens group outside the lens group. Even if the lens group is formed, the lens group and the housing become considerably large. The present embodiment solves these problems, and provides a lighting device with a scattering prevention hood that is easy to manufacture or that can be miniaturized, and a lighting system using the same.

First, a first mode according to the present embodiment is as follows.
One of the convex lenses arranged to face the spherical mirror 3 described in the third embodiment with reference to FIG. 8 is also used as a hood. That is, in FIG.
Outer diameter of the convex lens 31 (outer diameter in the direction perpendicular to the optical axis)
With the outer diameter of the spherical mirror 3 and this first convex lens 31
Cover the front surface of the arc lamp 2. Lighting device 3
With this configuration of the first convex lens 31 even if the arc lamp 2 is broken,
Prevents the components of the arc lamp 2 from scattering.

Next, in the prior art, the spherical mirror 3 and the hood 41 are different from each other as shown in FIG. FIG.
In a second mode according to the present embodiment shown in FIG.
5 is formed of a hollow sphere 46 made of a transparent material such as glass, and the arc lamp 2 is accommodated in the center of the sphere. Then, a semi-spherical portion corresponding to half of the hollow sphere 46 with respect to the arc lamp 2 is coated with a reflective film 47 to form a spherical mirror. The remaining hemisphere portion of the hollow sphere 46 is used as a hood. The use of the hollow spheres 46 eliminates the need to manufacture and assemble a separate hood, thereby increasing the efficiency of production.

According to this aspect, since the reflector and the hood are integrally formed, the manufacture is easier than in the prior art. However, the spherical shape is the same as the conventional technology (see FIG. 10). When the lens group is arranged on the front surface of the lighting device 45, the size becomes large as a whole. FIG. 12 shows a third embodiment according to the present embodiment for solving the problem of the increase.
3 shows the lighting device of the embodiment. In the figure, the spherical mirror 3
The hood 51 is formed in a flat shape approaching the arc lamp 2 at a portion intersecting with the optical axis and at a peripheral portion thereof (upper portion in the figure) while maintaining a spherical shape.

By forming the illumination device 50 in a deformed spherical shape in this manner, the lens group arranged on the front surface of the illumination device can be arranged at a position closer to the arc lamp 2, and the entire illumination system can be made more compact. can do. In the illustrated example, the illuminating device 50 is of a type in which the spherical mirror 3 and the hood 51 are combined. As in the case described with reference to FIG. If a hollow sphere having a body shape is used and a reflection film is provided at a portion corresponding to a spherical mirror, the number of components is reduced, and manufacturing is facilitated.

FIG. 13 shows a fourth embodiment of a lighting device 60 according to the present embodiment, which is an extension of this embodiment.
The arc lamp 2 is disposed inside a hollow sphere 61 including a flat spherical surface. A hood portion that is a part of the hollow sphere 61 forms a first convex lens 62 of the light collecting device. By forming the hood portion as the convex lens 62 in this way, it becomes possible to make the lens group below the second convex lens 63 closer to the arc lamp 2 as compared with the third embodiment, and further downsize the entire lighting system. be able to. The reflection film 47 is formed on a part of the hollow sphere 61,
The point that a spherical mirror is used is the same as in the second embodiment. Furthermore, as shown in FIG. 9, if a concave lens is inserted between the biconvex lenses 62 and 63, it becomes possible to obtain parallel light having a uniform luminous flux density.

[0066]

According to the illumination device of the present invention in which the center of the arc gap of the arc lamp is disposed at the spherical center of the hemispherical spherical mirror, the light emitted from the light source can be efficiently applied to the projection object. Becomes That is, an illumination device using a parabolic mirror or an ellipsoidal mirror generally used in the prior art is known.
While the light use efficiency is about 0 to 70%, in the lighting device according to the present invention, the efficiency can be made 90% or more. Therefore, if the illuminance is made equal to that of the illumination device according to the related art, the lens diameter can be made smaller, and further, the size of the housing of the illumination device can be made smaller.

More specifically, when a parabolic mirror or an elliptical mirror is used as a reflecting surface of an arc lamp of 120 to 150 W, the diameter of the illuminating device is limited to 50 mm even if the aperture is small. . In the lighting device according to the present invention, the opening has a diameter of 3
Since the diameter can be reduced to about 0 mm and the diameter including the condenser lens can be reduced to 40 mm, the size, particularly the thickness, of the housing can be reduced.

According to the illumination device of the present invention, the light generated from the arc is irradiated almost perpendicularly to the reflection film of the spherical mirror. Therefore, in any part of the spherical mirror, for example, it is possible to form a uniform reflective film that transmits ultraviolet light and infrared light and reflects only visible light, thereby efficiently transmitting only visible light to an irradiation target. Therefore, it is possible to prevent deterioration of an irradiation target or a member such as an integrator in the middle.

According to the illuminating device of the present invention, it is possible to reduce the burden on the integrator for reducing the illuminance unevenness on the screen by setting the condenser lens. Further, by combining the spherical mirror, the condenser lens, and the integrator, the illuminance unevenness on the illumination target can be reduced, and the illuminance unevenness on the screen can be reduced.

Further, according to the illumination device of the present invention in which the spherical mirror and the condenser lens are integrated, it is possible to provide a small illumination device which also prevents scattering of dangerous debris such as glass when the arc lamp is broken. it can.

According to the lighting device of the present invention,
By using a polarization alignment array and a polarization conversion prism together with a spherical mirror, a condensing lens, and an integrator, it is possible to obtain an LCD illumination device with higher illuminance.

[Brief description of the drawings]

FIG. 1 is a side view showing the principle of a lighting device according to the present invention,
It is a front view.

FIG. 2 is a side view showing a lighting system using the lighting device according to the present invention.

FIG. 3 is a side view showing another lighting system using the lighting device according to the present invention.

FIG. 4 is a side view showing still another lighting system using the lighting device according to the present invention.

FIG. 5 is a side view showing a lighting system using a plurality of lighting devices according to the present invention.

FIG. 6 is a side view showing another lighting system using a plurality of lighting devices according to the present invention.

FIG. 7 is a side view showing still another lighting system using a plurality of lighting devices according to the present invention.

FIG. 8 is a side view showing another embodiment of the lighting device according to the present invention.

FIG. 9 is a side view showing still another embodiment of the lighting device according to the present invention.

FIG. 10 is a side view showing a conventional lighting device provided with a hood.

FIG. 11 is a side view showing a lighting device according to the present invention including a hood.

FIG. 12 is a side view showing another embodiment of the illumination device according to the present invention having a hood.

FIG. 13 is a side view showing still another embodiment of a lighting device according to the present invention including a hood.

FIG. 14 is a side view illustrating an example of a lighting device according to the related art.

[Explanation of symbols]

1. Lighting device, 2. Arc lamp, 3. Spherical mirror,
4. Aspheric convex lens, 6. Electrodes, 7. Glass tube, 1
0. Liquid crystal display panel, 11. Element lens, 12. Macro lens array, 13. Cylindrical lens, 1
4. 1st cylindrical lens array, 15.1
/ 2λ plate; 17. polarization alignment prism array,
17. a second cylindrical lens array; Condenser lens, 19. Condenser lens, 20.
Integrator, 21. 30. polarization conversion prism,
Lighting device, 31. First convex lens, 32. 36. second convex lens, Concave lens, 40. Lighting equipment, 4
1. Glass hood, 45. Lighting device, 46. Hollow sphere, 47. Reflective film, 50. Lighting device, 55. Lighting device, 60. Lighting equipment.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F21V 7/22 G03B 21/14 A G02F 1/13 505 H04N 5/74 Z 1/13357 F21Y 101: 00 G03B 21/14 F21M 1/00 R H04N 5/74 7/00 H // F21Y 101: 00

Claims (17)

[Claims] 1. An arc lamp which comprises a concave mirror having a light reflecting surface, a pair of arc electrodes, generates an arc between the two arc electrodes and emits divergent light, and after being radiated from the arc lamp A light condensing device that condenses the light beam reflected by the concave mirror, wherein the concave mirror is a hemispherical surface or a spherical mirror having a light reflecting surface formed on the inner surface of a spherical surface smaller than the hemispherical surface, By arranging the spherical center of the spherical mirror and the center of the gap between the pair of arc electrodes of the arc lamp substantially coincident with each other, light rays diverging from the arc and reflected by the spherical mirror and direct rays diverging from the arc are emitted. An illuminating device, wherein the illuminating device emits light to the light collecting device while superimposing the light. 2. The illumination device according to claim 1, wherein the light condensing device is formed by an aspheric convex lens. 3. The lighting device according to claim 1, wherein the light collecting device is constituted by a plurality of convex lenses. 4. The light-collecting device comprises a plurality of convex lenses and at least one concave lens, and a light amount per unit area is substantially uniform near a center of a main optical axis and a peripheral portion, or The lighting device according to claim 1, wherein the powers of the plurality of convex lenses and the at least one concave lens are adjusted so that the peripheral portion is smaller than the vicinity of the center of the main optical axis. 5. The apparatus according to claim 2, wherein one of the lenses constituting a part of the light-collecting device also functions as a hood for preventing the arc lamp from scattering. Lighting equipment. 6. The spherical mirror is formed by coating a light reflecting film on a hemisphere of a hollow sphere made of a transparent material, and the remaining hemisphere of the hollow sphere forms a hood for preventing the arc lamp from scattering. The lighting device according to any one of claims 1 to 4, wherein the lighting device is used. 7. A hood formed by a hemispherical surface of the hollow sphere, a position intersecting with a main optical axis of a light beam reflected from the spherical mirror, and its periphery formed in a flat shape close to the spherical center of the hollow sphere. The lighting device according to claim 6, wherein: 8. The lighting device according to claim 6, wherein the hood also serves as one of the convex lenses forming a part of the light collecting device. 9. The light reflecting film of the spherical mirror is formed as a light reflecting surface that transmits one or both of ultraviolet light and infrared light and reflects at least light in a visible light region. The lighting device according to any one of claims 1 to 8. 10. A lighting system, wherein the lighting device according to any one of claims 1 to 9 is configured to emit a light beam to a set of integrators. 11. An illuminating device comprising a plurality of the illuminating devices according to claim 1, wherein the illuminating device is configured to emit a light beam toward a set of integrators. Lighting system. 12. The apparatus according to claim 10, further comprising a polarization function for aligning random light of an arc diverging from the arc lamp to one of P-polarized light and S-polarized light. The lighting system according to claim 1. 13. The illumination system of claim 12, wherein the polarization function comprises a polarization-aligned prism array. 14. The illumination system according to claim 12, wherein the polarization function includes two polarization conversion prisms. 15. A spherical mirror in which a light reflecting surface is formed on the inner surface of a hemisphere or a hemisphere or less, a arc lamp in which a center of a gap between a pair of arc electrodes is arranged at a spherical center of the spherical mirror, and an arc lamp generated from the arc lamp. An illumination device comprising: a light condensing device that superimposes and converges the light beam reflected by the spherical mirror and the direct light divergent from the arc; and divides the one light beam into a plurality of light beams. A lens plate having a plurality of element lenses similar in shape to the screen to be illuminated, a convex lens for superimposing each of the divided light beams on the illumination target, and an arc created by a lens plate having the plurality of element lenses A pair of mutually orthogonal cylindrical lens arrays for forming an image together with the convex lens on an object to be illuminated. Ming system. 16. The illumination system further includes a polarization function of irradiating the illumination target by aligning random light generated by the arc lamp with one of S-polarized light and P-polarized light. The lighting system according to claim 15, wherein: 17. An illumination method in which a light beam diverged from an arc lamp is reflected by a concave mirror, and the reflected light beam is condensed and used to illuminate an object to be illuminated. A spherical mirror having a light reflecting surface formed on the inner surface of the following spherical surface, wherein the spherical center of the spherical mirror and the center of the gap between the electrodes for generating the arc substantially coincide with each other, whereby the spherical mirror diverges from the arc. A light beam reflected by the light source and a direct light beam diverging from the arc are converged and collected.