JPH04281441A - Lighting device - Google Patents

Abstract

PURPOSE:To irradiate an object surface with all light which is emitted by a light source in all directions by surrounding the light source with the concave reflecting mirror which consists of an elliptic surface and a circular arcuate surface and making the light incident on a parallel light converting lens from an opening provided in the circular arcuate surface as to the lighting device which lights the surface with the light from the light source efficiently in a specific direction and in parallel or nearly in parallel. CONSTITUTION:The concave reflecting surface is so sectioned as to have the circular arcuate surface having the opening centering on the optical axis is front of the light source and the elliptic surface behind the light source; and the light source is arranged at an a 1st nearly focus position of the elliptic surface and the circular arcuate surface is positioned at a 2nd nearly focus position. The elliptic surface and the circular arcuate surface have the 1st nearly focus position and the nearly focus position at the same position.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device that efficiently irradiates light from a light source in a specific direction and in a parallel or nearly parallel state.

0002

[Prior Art] Conventionally, in a liquid crystal projection type image display device, etc., in which light is irradiated from the back of a liquid crystal and the image presented on the liquid crystal is enlarged and projected by a projection optical system, lighting for irradiating the liquid crystal with light is used. The performance of the device is required to be able to irradiate each pixel of the liquid crystal with light in the perpendicular direction, that is, as parallel as possible, due to the light incident angle characteristics of the liquid crystal.

As a condensing optical system for an illumination device that achieves this purpose, (1) as shown in FIG. The light source 1 is placed at the focal position A of the parabolic reflector 2 in combination with a parabolic reflector 2 whose cross-sectional shape with respect to the axis is a paraboloid and is arranged so as to partially surround the light source 1. (2) a condensing optical system that irradiates parallel light onto an irradiated surface 3 such as a liquid crystal by reflecting a part of the irradiated light from 1 by a parabolic reflector 2;
As shown in FIG. 8, a light source 1 is combined with an arcuate reflector 4 and a positive lens (convex lens) 5 whose cross-sectional shape with respect to the optical axis is an arcuate surface and surrounds a part of the light source 1. Focal position B where the focal point and the focal point of the positive lens 5 are the same
The light source 1 is placed at lens 5
(3) As shown in FIG. 9, the light source 1 has an elliptical cross-sectional shape with respect to the optical axis. The light source 1 is placed at one focal point C of the ellipsoidal reflector 6 by combining an ellipsoidal reflector 6 that surrounds a part of the light source 1 with a surface and a positive lens 7, and the light source 1 is A part of the light is reflected and condensed by the ellipsoidal reflector 6, and after passing through a focal point D where the other focus of the ellipsoidal reflector 6 and the focus of the positive lens 7 are the same, the positive lens 7
A condensing optical system (Japanese Patent Publication No. 1-25046) is known, which irradiates parallel light onto the irradiated surface 3 by making it incident on the irradiated surface. A light source is placed at or near the focal point of the mirror (approximately the focal point), and a portion of the light emitted from the light source is directly irradiated onto the irradiated surface using a reflecting mirror, or a portion of the light emitted from the light source is irradiated directly onto the irradiated surface using a combination of a reflecting mirror and a positive lens. It is an optical system that efficiently condenses the irradiated light from the light source using a reflecting mirror, positive lens, etc.

0004

[Problems to be Solved by the Invention] In the conventional condensing optical system, the light source 1 theoretically has the characteristic of emitting light evenly in all directions (angle α is 360 degrees in FIGS. 7 to 9). If the surface 3 is irradiated with all the light at an angle of 360 degrees from the light source 1, the light utilization efficiency of the light source 1 becomes 100%.

However, in all of the conventional condensing optical systems described above, out of the light emitted from the light source 1, only light within a range where the angle α is narrower than 360 degrees is reflected due to the optical characteristics of the reflecting mirror and the positive lens. The reality is that the light from the remaining angle β (=360 degrees - α), that is, a part of the direct light from light source 1, cannot be made to enter a mirror or positive lens, so the light source There is a problem in that the light utilization efficiency in No. 1 cannot be made 100%.

Furthermore, since the light source 1 generally uses a halogen bulb, metal halide lamp, short arc type xenon lamp, etc., the irradiated surface 3 is irradiated not only with visible light but also with ultraviolet rays and infrared rays. Therefore, there is a risk that they may cause trouble (deterioration of characteristics, damage, etc.) to the liquid crystal etc. arranged on the irradiated surface 3.

[0007]

[Means for Solving the Problems] The present invention includes a light source whose light emitting portion is point-like, and whose cross-sectional shape is a compound curved surface of an elliptical surface and an arc surface.
and a concave reflecting mirror that surrounds the light source, and a parallel light conversion lens that converts the reflected light from the concave reflecting mirror and the irradiated light from the light source into parallel light, and the concave reflecting mirror is arranged in front of the light source. The side is an arcuate surface having an opening at the center of the optical axis, and the rear side of the light source is an elliptical surface, and the light source is arranged at a first approximate focal position of the ellipsoidal surface, and the arcuate surface is arranged at a second approximate focal position of the ellipsoidal surface. , is an illumination device in which the first approximate focal point position of the ellipsoidal surface and the approximately focal position of the circular arc surface are made the same.

The present invention is also characterized in that the size of the aperture provided at the center of the optical axis of the arcuate surface of the concave reflecting mirror is variable.

Furthermore, the present invention has the characteristic that the elliptical surface of the concave reflector transmits ultraviolet rays and infrared rays and reflects visible light.
The arcuate surface has a characteristic of reflecting ultraviolet rays, visible light, and infrared rays, and the parallel light conversion lens has a characteristic of transmitting visible light and reflecting ultraviolet rays and infrared rays.

The present invention is also characterized in that the light source, the concave reflecting mirror, and the parallel light conversion lens are arranged on the same optical axis, and the parallel light conversion lens is moved parallel to the optical axis.

[0011]

[Operation] In the present invention, in the concave reflecting mirror, the light irradiated from the light source in the direction away from the irradiated surface (to the rear side of the light source) is focused at the second approximate focal point by the elliptical surface. After that, the light enters the parallel light conversion lens and is focused on the irradiated surface as parallel light. On the other hand, most of the light emitted in the direction approaching the irradiated surface (in front of the light source) is returned to the light source position by the arc surface (approximately the focal position of the arc surface and the same position as the first approximately focal position of the ellipsoid surface). After the light is focused at a second approximate focal point by the elliptical surface, it enters the parallel light conversion lens and is focused on the irradiated surface as parallel light. Further, of the light irradiated from the light source, the remaining light irradiated in a direction approaching the irradiated surface directly exits the aperture of the arcuate surface and enters the parallel light conversion lens. Due to the above-mentioned effects, all the light radiated from the light source in all directions can be irradiated onto the irradiated surface.

In addition, by adjusting and varying the size of the aperture provided at the center of the optical axis of the arcuate surface of the concave reflecting mirror, even if the light source has a certain size, the irradiation light from the light source can be adjusted. A part of the parallel light can be effectively input to the parallel light conversion lens without being blocked by the arcuate aperture.

Furthermore, in the concave reflecting mirror, of the light irradiated from the light source, the elliptical surface transmits ultraviolet rays and infrared rays, only visible light is reflected and enters the parallel light conversion lens, and the arcuate surface transmits ultraviolet rays and visible rays. , Infrared rays reach the ellipsoidal surface after being reflected and returned to the light source position, and ultraviolet rays and infrared rays are transmitted, and only visible light is reflected and enters the parallel light conversion lens, so visible light does not appear on the irradiated surface. can only be irradiated.

Furthermore, by arranging the light source, the concave reflecting mirror, and the parallel light conversion lens on the same optical axis, and moving the parallel light conversion lens parallel to the optical axis, the parallel light conversion lens and As the distance from the approximate focal point changes, part of the irradiated light from the parallel light conversion lens converges or diverges.
Not only can it irradiate light that matches the light incident angle characteristics of the irradiated surface, but also the intensity (brightness) of the light to the irradiated surface can be adjusted arbitrarily.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view showing the configuration of a condensing optical system for an illumination device according to the present invention. In FIG. 1, 8 is a light source with a point-like light emitting portion (for example, a halogen bulb, a metal halide lamp, or a short arc type xenon lamp), which irradiates light evenly in all directions (360 degrees). Rotate 2 so as to surround this light source 8.
A concave reflecting mirror 9 having a curved surface is arranged. This concave reflecting mirror 9 has an ellipsoidal surface 10 in its rear half from the light source 8 and a curved arc surface 11 in its front half, and an aperture φ is provided at the center E of the optical axis of the arcuate surface 11. ing. Under such conditions, the first approximate focal position of the ellipsoidal surface 10 and the approximate focal position of the arcuate surface 11 are made the same and are defined as the approximate focal position F, and the light source 8 is arranged at the approximate focal position F.

On the other hand, an arcuate surface 11 is arranged so as to overlap the second approximate focal point position of the ellipsoidal surface 10. Since this position is the same as the aperture φ of the arcuate surface 11, this position is defined as a substantially focal position E (=optical axis center E).

In the concave reflecting mirror 9, the junction point between the ellipsoidal surface 10 and the arcuate surface 11 is G, the solid angle formed with the approximate focal point E is γ, and parallel light is generated within the range opposite to this solid angle γ. A conversion lens 12 is arranged. At this time, the focal point of the parallel light conversion lens 12 is set to approximately the same position as the focal point position E.

Note that in FIG. 1, a light source 8, a concave reflecting mirror 9
, the ellipsoidal surface 10, the arcuate surface 11, and the parallel light conversion lens 12 are all optically arranged on the same optical axis (P-P in FIG. 1).

The principle for obtaining parallel light in such a configuration will be explained below. Elliptical surface 1 from behind light source 8
Considering the irradiation path of the light toward 0, the irradiation light from the light source 8 is reflected by the ellipsoidal surface 10 and then converged toward the aperture φ of the arcuate surface 11, that is, toward the approximate focal point E.

Next, considering the irradiation path of light from the front side of the light source 8 toward the arcuate surface 11, most of the irradiation light from the light source 8, after being reflected by the arcuate surface 11, reaches the approximate focal point F, that is, the light source 8. The light returns to , converges (indicated by the broken line in FIG. 1), and heads toward the ellipsoidal surface 10 as if it were irradiated from the light source 8. After being reflected at the ellipsoidal surface 10 in the same manner as described above, the light converges toward the aperture φ of the arcuate surface 11, that is, toward the approximate focal point E.

Further, a portion of the light directed toward the arcuate surface 11 from the front side of the light source 8 directly travels to approximately the focal point E.

As described above, it can be seen that the irradiated light from the light source 8 in any direction tends to finally converge at the approximate focal point E by the ellipsoidal surface 10 or the circular arc surface 11 in the concave reflecting mirror 9.

The irradiated light from the approximate focal position E diverges again and enters the parallel light conversion lens 12, and is finally converted into parallel light to irradiate the illuminated surface 13 such as a liquid crystal.

Next, a second embodiment of the present invention will be explained based on the attached drawings. FIG. 2 is a sectional view showing the configuration of a condensing optical system for a lighting device according to the present invention. In FIG. 2, the basic positional relationships and names of the constituent parts are the same as in the first embodiment described above, and their explanation will be omitted in this embodiment.

The difference in the second embodiment from the first embodiment is that the size φD of the opening φ provided in the arcuate surface 10 of the concave reflecting mirror 9 is different from the direction perpendicular to the optical axis PP. The structure is designed to change.

In the first embodiment of the present invention, the light source 8 is a point light source, but in reality, the light emitting portion of the light source has a certain size.

The second embodiment of the present invention presents a condensing optical system that irradiates parallel light onto the irradiated surface 13 when the light source 8 has a certain size as described above. I will explain its principle.

In FIG. 2, the light source 8 has a size x in the direction of the optical axis P--P, and is located approximately at a focal position F. Under these conditions, the light directed toward the ellipsoid 10 from the part of the light source 8 closer to the ellipsoid 10 (the part Xr in FIG. 2) is reflected by the ellipsoid 10 and then becomes substantially parallel to the focal point E. It attempts to converge to a position Ef close to the light conversion lens 12 (the path of the irradiated light is shown by a broken line in FIG. 2).
.

Next, the light directed toward the ellipsoidal surface 10 from the portion of the light source 8 that is closer to the arcuate surface 11 (the portion Xf in FIG. 8 (indicated by the two-dot chain line in FIG. 2).

If the light source 8 is an ideal point light source, the size φD of the aperture φ of the circular arc surface 11 at the approximate focal point E is as follows.
As with the light source 8, it is sufficient if it is point-like, that is, pinhole-like. However, when the light source 8 has a size x as in the present invention, if φD is too small, the irradiated light from the light source 8 will not be able to pass through the aperture φ, and some of the light will be blocked. become. Therefore, according to the size x of the light source 8, the aperture φ
The size φD is expanded (changed) in a direction perpendicular to the optical axis P-P. By doing so, the irradiated light from the light source 8 can efficiently pass through the aperture φ and enter the parallel light conversion lens 12, so that the irradiated surface 13 can finally be irradiated with parallel light. It is something.

In the present invention, the size of the opening φD
Although it does not detail how to change the
It is possible to prepare several types of apertures φ with different φD as individual parts and install them on the arcuate surface 11 according to the size x of the light source 8, or to construct the aperture φ portion of the arcuate surface from a plurality of aperture blades. By using such a diaphragm mechanism, the size φD of the aperture φ can be changed.

Next, a third embodiment of the present invention will be explained based on the attached drawings. FIG. 3 is a sectional view showing the configuration of a condensing optical system for a lighting device according to the present invention. In FIG. 3, the basic positional relationships and names of the constituent parts are the same as in the first embodiment described above, and their explanation will be omitted in this embodiment.

The third embodiment differs from the first embodiment in that (1) the ellipsoidal surface 10 of the concave reflecting mirror 9 transmits ultraviolet and infrared rays of the light emitted from the light source 8, and transmits visible light; have the property of reflecting only (2) The parallel light conversion lens 12 has a characteristic of reflecting ultraviolet rays and infrared rays of the light emitted from the light source 8 and transmitting only visible light. It is.

In general, halogen bulbs, metal halide lamps, xenon lamps, and the like have a spectral power distribution characteristic of emitting (irradiating) light with a wide range of wavelengths from near ultraviolet to visible light to infrared. Therefore, when these light sources are incorporated into the condensing optical system of a liquid crystal projection image display device, the liquid crystal, which is the surface to be illuminated, will of course be irradiated with light of the aforementioned wide wavelength range. Problems arise when ultraviolet and infrared rays cause problems such as deterioration of characteristics and damage to liquid crystals.

The third embodiment of the present invention presents a condensing optical system that irradiates only visible light without irradiating the surface to be irradiated with ultraviolet rays and infrared rays, and the principle thereof will be described below.

In FIG. 3, a light source 8 emits mainly visible light (indicated by a solid line in FIG. 3) as well as ultraviolet rays and infrared rays (indicated by a broken line in FIG. 3).

First, considering the irradiation path of light from the light source 8 to the ellipsoidal surface 10, the irradiated light from the light source 8 is optically separated into visible light, ultraviolet rays, and infrared rays at the ellipsoidal surface 10, and only the visible light is reflected. After that, the ultraviolet rays and infrared rays converge toward the approximate focal point E, and the ultraviolet rays and infrared rays pass through the ellipsoidal surface 10 and diverge.

Next, considering the irradiation path of light from the light source 8 to the arcuate surface 11, most of the irradiated light from the light source 8 is reflected by the arcuate surface 11 after all of the ultraviolet rays, visible light, and infrared rays. , converges toward the approximate focal point F, that is, the light source 8, and heads toward the ellipsoidal surface 10 as if irradiated from the light source 8, and as before, ultraviolet and infrared rays are transmitted by the ellipsoidal surface 10, and only visible light is reflected. , converge toward approximately the focal position E.

Furthermore, a portion of the light that travels from the front side of the light source 8 toward the arcuate surface 11 directly travels toward approximately the focal point E and enters the parallel light conversion lens 12 . The parallel light converting lens 12 reflects the ultraviolet rays and infrared rays of the light emitted from the light source 8, and transmits only the visible light.

As described above, it can be seen that among the irradiated light from the light source 8, that is, ultraviolet rays, visible light, and infrared rays, only visible light is ultimately selected and tends to converge at approximately the focal point E. The subsequent visible light irradiation path is the same as in the first embodiment,
The irradiated light from the approximate focal point E diverges again and enters the parallel light conversion lens 12, and finally becomes parallel light and hits the irradiated surface 1.
3 will be irradiated with only visible light.

In the present invention, the means for separating visible light from ultraviolet and infrared rays is not described in detail, but methods using multilayer metal vapor deposition films are generally known.

Next, a fourth embodiment of the present invention will be explained based on the attached drawings. FIG. 4 is a sectional view showing the configuration of a condensing optical system for an illumination device according to the present invention. In FIG. 4, the basic positional relationships and names of the constituent parts are the same as in the first embodiment described above, and their explanation will be omitted in this embodiment. The difference between the fourth embodiment and the first embodiment is that the parallel light conversion lens 12 is moved parallel to the optical axis P-P with the approximate focal position E as a reference (closer to the approximate focal position E, ).

In FIG. 4, the parallel light converting lens 12 is indicated by a chain double-dashed line.
2 is moved in parallel by ΔL towards the irradiated surface 13 (
(state where the parallel light conversion lens 12 is separated from the approximate focal position E)
At this time, the approximate focal position E and the parallel light conversion lens 12
The distance from this point is L+ΔL.

Similarly, in FIG. 4, parallel light conversion lens 1
2 is shown by a broken line when the parallel light conversion lens 12 is translated by ΔL toward the approximate focal position E with respect to the distance L between the approximate focal position E and the end surface of the parallel light conversion lens 12 ( The parallel light conversion lens 12 is brought close to the approximate focal position E), and the approximate focal position E and the parallel light conversion lens 1 at this time are
The distance from 2 is L-ΔL.

Under the above conditions, considering the irradiation path of light from the light source 8 to the irradiated surface 13 via the parallel light conversion lens 12, first, when the parallel light conversion lens 12 is separated from the approximate focal point E by ΔL. At (L+ΔL), the irradiated light from the light source 8 is incident on the parallel light conversion lens 12 after being converged to approximately the focal position E. Here, the parallel light conversion lens 12
Since the light moves away from the approximate focal point E, the irradiated surface 13 is irradiated with slightly converged light (indicated by a two-dot chain line in FIG. 4). This has the function of making the irradiated surface 13 brighter in the vicinity of the optical axis P-P and darker in the area away from the optical axis.

Next, when the parallel light conversion lens 12 is brought close to the approximate focal position E (L-△L), the irradiated light from the light source 8 converges at the approximate focal position E and then passes through the parallel light conversion lens. 12. Here, since the parallel light conversion lens 12 approaches approximately the focal point E, the irradiated surface 13 is irradiated with slightly divergent light (indicated by a broken line in FIG. 4). This has the function of making the irradiated surface 13 darker in the vicinity of the optical axis PP and brighter in the area away from the optical axis PP.

With the above configuration, the parallel light conversion lens 12
By changing the position of the light in the direction of the optical axis P-P and making adjustments such as slightly converging or diverging a part of the irradiated light, light that matches the light incident angle characteristics of the irradiated surface 13 can be produced. Not only can it be irradiated, but also the irradiated surface 13
The intensity (brightness) of the light can be adjusted arbitrarily.

Next, a fifth embodiment of the present invention will be explained based on the attached drawings. FIG. 5 is a sectional view showing the configuration of a condensing optical system for an illumination device according to the present invention. In FIG. 5, the basic positional relationships and names of the constituent parts are the same as in the second embodiment described above, and their explanation will be omitted in this embodiment.

The difference between the fifth embodiment and the second embodiment is that the concave reflecting mirror 9 is moved parallel to the optical axis P-P with the end face of the parallel light conversion lens 12 as a reference (parallel light conversion (bringing it closer to or away from the lens 12). In FIG. 5, the concave reflecting mirror 9 is indicated by a chain double-dashed line, and the end surface of the parallel light conversion lens 12 and the approximate focal point E.
The concave reflecting mirror 9 is moved in parallel by ΔM toward the light source 8 with respect to the distance L from the parallel light converting lens 12 (the concave reflecting mirror 9 is separated from the parallel light converting lens 12). 12 and the concave reflecting mirror 9 is L+ΔM.

Similarly, in FIG. 5, the concave reflecting mirror 9 is indicated by a broken line because the concave reflecting mirror 9 is indicated by a broken line with respect to the distance L between the end surface of the parallel light converting lens 12 and the approximate focal point E. 12 (the concave reflecting mirror 9 is brought close to the parallel light converting lens 12), and the distance between the parallel light converting lens 12 and the concave reflecting mirror 9 at this time is L - ΔM. becomes.

Under the above conditions, considering the irradiation path of light from the light source 8 to the irradiated surface 13 via the parallel light conversion lens 12, first, if the concave reflector 9 is separated from the parallel light conversion lens 12 by ΔM. , the irradiated light from the light source 8 is reflected by the elliptical surface 10 and the circular arc surface 11, and then reaches the approximate focal point E.
The light converges toward r and enters the parallel light conversion lens 12. Here, since the concave reflecting mirror 9 moves away from the parallel light conversion lens 12, the irradiated surface 13 is irradiated with slightly convergent light (indicated by a two-dot chain line in FIG. 5). This has the effect of making the area near the optical axis PP brighter on the irradiated surface 13.

Next, the concave reflecting mirror 9 is replaced with a parallel light converting lens 1.
2 by ΔM, the irradiated light from the light source 8 is reflected by the ellipsoidal surface 10 and the circular arc surface 11, converges toward the approximate focal point Ef, and enters the parallel light conversion lens 12. Here, since the concave reflecting mirror 9 approaches the parallel light conversion lens 12, the irradiated surface 13 is irradiated with slightly divergent light (indicated by a broken line in FIG. 5). This has the effect of making the portions of the irradiated surface 13 farther away from the optical axis PP brighter.

With the above configuration, by changing the position of the concave reflecting mirror 9 and making adjustments such as slightly converging or diverging a part of the irradiated light from the parallel light conversion lens 12, the irradiated surface can be adjusted. Not only can it irradiate light that matches the light incident angle characteristics of 13, but also the irradiated surface 1
The intensity (brightness) of the light to 3 can be adjusted arbitrarily.

Next, a sixth embodiment of the present invention will be described based on the accompanying drawings. FIG. 6 is a sectional view showing the configuration of a condensing optical system for a lighting device according to the present invention. In FIG. 6, the basic positional relationships and names of the constituent parts are the same as in the second embodiment described above, and their explanation will be omitted in this embodiment. The difference between the sixth embodiment and the second embodiment is that the light source 8 is moved along the optical axis P with the approximate focal point E as a reference.
−P (to move it closer to or away from the approximate focal point E).

In the first to fifth embodiments of the present invention,
Although the configuration and principle have been described under the condition that the light source 8 is arranged at approximately the focal position F of the concave reflecting mirror 9, it is not necessarily arranged at approximately the focal position F due to the positional accuracy of the arrangement of the light source 8. do not have.

In the sixth embodiment of the present invention, when the light source 8 is disposed at a position shifted from the approximate focal point F as described above, a condensing optical system is used to irradiate the irradiated surface 13 with parallel light. The principle is described below.

In FIG. 6, from the approximate focal point F, the ellipsoidal surface 1
The broken line showing the light source 8 at the position Fr closer to the 0 side shows the state where the light source 8 has been moved in parallel by ΔN towards the ellipsoidal surface 10, and the approximate focal position E and the light source 8 at this time are The distance is N with respect to the distance N between the approximate focal position F and the approximate focal position E.
+ΔN.

Similarly, in FIG. 6, the reason why the light source 8 is indicated by a broken line at a position Ff closer to the arcuate surface 11 than the approximate focal point F is to move the light source 8 toward the arcuate surface 11 on the optical axis P-P. ΔN
The distance between the approximate focal position E and the light source 8 at this time is the approximate focal position F and the approximate focal position E.
The distance N between the two points is N - ΔN.

Under the above conditions, considering the irradiation path of light from the light source 8 to the irradiated surface 13 via the parallel light conversion lens 12, first, when the light source 8 is placed at approximately the focal position Fr, the light source 8 After being reflected by the ellipsoidal surface 10, the irradiated light is converged toward approximately the focal point Ef and enters the parallel light conversion lens 12. Here, since the light source 8 is closer to the parallel light conversion lens 12 than the approximate focal point E, the irradiated surface 13
In contrast, the light is irradiated as slightly divergent light (indicated by a broken line in FIG. 6). This has the function of making the area near the optical axis PP darker with respect to the irradiated surface 13, and making the area farther away from the optical axis PP brighter.

Next, when the light source 8 is placed at approximately the focal position Ff, the irradiated light from the light source 8 is reflected by the ellipsoidal surface 10, and then converged toward the approximately focal position Er, and the parallel light converting lens 12. Here, since the light source 8 is away from the parallel light conversion lens 12 from the approximate focal point E, the irradiated surface 13
The light is irradiated as slightly convergent light (indicated by a two-dot chain line in FIG. 6). This has the function of making the area near the optical axis PP brighter on the irradiated surface 13, and making the area farther away from the optical axis PP darker.

With the above configuration, even if the position of the light source 8 changes on the optical axis P-P due to variations in the position of the light source 8, this position can be adjusted and a part of the irradiated light from the parallel light conversion lens 12 can be changed. By making adjustments such as slightly converging or diverging, it is possible not only to irradiate light that matches the light incident angle characteristics of the irradiated surface 13, but also to increase the intensity (brightness) of the light to the irradiated surface 13. ) can be adjusted arbitrarily.

In the fourth to sixth embodiments of the present invention, the means for moving the light source 8, concave reflecting mirror 9, and parallel light conversion lens 10 in parallel to the optical axis P-P will be described in detail. However, it can be realized by using a sliding mechanism using linear motion or a feeding mechanism using rotational motion, and combining this mechanical system with a drive system such as a motor, a spring, or a manual drive system.

[0064]

[Effects of the Invention] As described above, in the present invention, the following effects can be obtained.

(1) The shape of the concave reflecting mirror is such that the front side of the light source is an arcuate surface with an opening at the center of the optical axis, and the rear side of the light source is an ellipsoidal surface, and the light source is placed at the first approximate focal point of the ellipsoidal surface. By arranging the arcuate surface at the second approximate focal point and making the first approximate focal point of the elliptical surface and the approximate focal point of the arcuate surface the same, all the light emitted from the light source in all directions can be directed to the irradiated surface. It can be irradiated.

(2) In a concave reflecting mirror, by adjusting and varying the size of the aperture provided at the center of the optical axis of the arcuate surface, even if the light source has a certain size, the irradiation from the light source can be controlled. Part of the light is not blocked by the arcuate opening,
The parallel light can be effectively input to the parallel light conversion lens.

(3) In a concave reflecting mirror, of the light emitted from the light source, the elliptical surface transmits ultraviolet and infrared rays, only visible light is reflected and enters the parallel light conversion lens, and the arcuate surface transmits ultraviolet and visible light. Both light and infrared rays are reflected and returned to the light source position before reaching the ellipsoidal surface, where ultraviolet rays and infrared rays are transmitted, and only visible light is reflected and enters the parallel light conversion lens, so there is no visible light on the irradiated surface. Only light can be irradiated.

(4) By arranging a light source, a concave reflecting mirror, and a parallel light conversion lens on the same optical axis, and moving the parallel light conversion lens parallel to the optical axis, a parallel light conversion lens can be formed. As the distance between the focal point and the focal point changes, part of the irradiated light from the parallel light conversion lens converges or diverges, so it is possible to irradiate light that matches the light incident angle characteristics of the irradiated surface. The intensity (brightness) of the light to the illuminated surface can be adjusted arbitrarily.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a lighting device in a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a lighting device that changes the size of the aperture of an arcuate surface in a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a device that irradiates only visible light onto an irradiated surface in a third embodiment of the present invention.

FIG. 4 is a configuration diagram of an illumination device that moves a parallel light conversion lens parallel to the optical axis in a fourth embodiment of the present invention.

[Figure 5
] A configuration diagram of an illumination device that moves a concave reflecting mirror parallel to the optical axis in a fifth embodiment of the present invention.

FIG. 6 is a configuration diagram of an illumination device that moves a light source parallel to the optical axis in a sixth embodiment of the present invention.

[Figure 7] Configuration diagram of a condensing optical system using a conventional parabolic reflector

[Figure 8] Configuration diagram of a condensing optical system using a conventional arcuate reflector and a positive lens

[Figure 9] Configuration diagram of a condensing optical system using a conventional ellipsoidal reflector and a positive lens

[Explanation of symbols]

8 Light source 9 Concave reflector 10 Ellipsoid 11 Arc surface 12 Parallel light conversion lens 13 Irradiated surface

Claims (6)

[Claims] 1. A light source with a point-like light emitting portion, a concave reflector whose cross-sectional shape is a compound curved surface of an elliptical surface and an arcuate surface and surrounds the light source, and light reflected from the concave reflector and from the light source. and a parallel light conversion lens that converts the irradiated light of , and disposing the light source at a first approximate focal position of the ellipsoidal surface, and arranging the arcuate surface at a second approximately focal position of the ellipsoidal surface,
An illumination device characterized in that a first approximate focal point position of the ellipsoidal surface and an approximately focal position of the arcuate surface are made the same. 2. The illumination device according to claim 1, wherein the concave reflecting mirror has a variable opening size. 3. In a concave reflecting mirror, the elliptical surface has the property of transmitting ultraviolet rays and infrared rays and reflecting visible light, and the arcuate surface has the property of reflecting both ultraviolet rays, visible light, and infrared rays.
3. The illumination device according to claim 1, wherein the parallel light converting lens has characteristics of transmitting visible light and reflecting ultraviolet rays and infrared rays, respectively. 4. The optical axis of the light source, the concave reflecting mirror, and the parallel light conversion lens are all on the same optical axis, and the parallel light conversion lens moves parallel to the optical axis. 3. The lighting device according to 1, 2 or 3. 5. The optical axis of the light source, the concave reflecting mirror, and the parallel light conversion lens are all on the same optical axis, and the concave reflecting mirror moves parallel to the optical axis. ,2
, 3 or 4. The lighting device according to . 6. The optical axis of the light source, the concave reflecting mirror, and the parallel light conversion lens are all on the same optical axis, and the light source moves parallel to the optical axis. The lighting device according to any one of.