JP2000275731A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a light source device constituted so that the efficiency of light utilization can be enhanced and the diameter of emitted light can be made small at the same time. SOLUTION: This light source device 1 is provided with a light source lamp 2 and four condensing lenses 3(1)-3(4) cocentrically surrounding the light emission part 2a of the lamp 2. Then, the light diverging from the lamp 2 surrounded by four lenses is radially emitted and reflected in the direction of a lamp optical axis L1 by reflectors 4(1)-4(4) arranged outside the lenses 3(1)-3(4). The reflected beams are synthesized through condensing lenses 5(1)-5(4) being light synthesizing elements arranged in front of the reflectors and made into single luminous flux whose diameter is small. Thus, the light source constituted so that the utilizing efficiency of the light is enhanced and the luminous flux whose diameter is small can be emitted can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small and efficient light source device used for a slide projector, a liquid crystal projector and the like.

[0002]

2. Description of the Related Art As a light source device used for a liquid crystal projector or the like, an apparatus as shown in FIG. 3 is known. The light source device 1A shown in this figure has a configuration including a lamp 2A such as a metal halide lamp having a light emitting section 3A, and a parabolic reflector 30 having a circular opening 30a. A lamp mounting hole 30b is formed in the center of the bottom of the parabolic reflector 30, and one end of the lamp 2A is
1 is in a fixed state.

In the light source device 1A having this configuration, the light emitted from the lamp light emitting section 3A is reflected by the parabolic reflector 30 and emitted from the front circular opening 30a as a light beam parallel to the lamp optical axis L. . The diameter of the light beam emitted from the circular opening 30a is determined by the focal length of the parabolic reflector 30 and the angle (light emission angle) of the light emitted from the lamp light emitting unit 3A.

Further, as a light source device used for a slide projector or the like, a device as shown in FIG. 4 is known. The light source device 1B shown in this figure has a lamp 2B provided with a light emitting section 3B, a spherical reflecting mirror 35 arranged on one side of the lamp light emitting section 3B with the lamp optical axis L interposed therebetween, and arranged on the other side. And a condenser lens 36.

In the light source device 1B having this configuration, the light emitted from the lamp light emitting section 3B is divided into a light component heading toward the spherical reflecting mirror 35 and a light component heading directly to the condenser lens 36. The light component heading for the spherical reflecting mirror 35 is reflected by the spherical reflecting mirror 35 and re-enters the lamp light emitting unit 3B,
Thereafter, the condenser lens 3 is moved from the light emitting section 3B.
Go to 6. Accordingly, the light emitted from the lamp light emitting section 3 is finally guided to the condenser lens 36, and is emitted by the lens 36 as a light beam having a predetermined angle.

[0006]

In recent years, there has been a demand for a light source device to increase the utilization efficiency of light emitted from a lamp and to reduce the size of the system. Also,
It is required to reduce the diameter of the emitted light beam and to increase the parallelism of the emitted light beam.

However, in the light source device 1A having the configuration shown in FIG. 3, it is necessary to increase the focal length of the parabolic reflector 30 in order to obtain a highly parallel emitted light beam. That is, it is necessary to employ a large parabolic reflector. Such an increase in the size of the parabolic reflector causes an increase in the size of the system. This leads to an increase in the occupied space of the light source device in a liquid crystal projector or the like, which leads to an increase in the size of the device incorporating the light source device. In addition, when the parabolic reflector is enlarged, the circular opening of the parabolic reflector naturally becomes large, and the diameter of the emitted light beam also becomes large.
In order to efficiently use such an emitted light beam, an optical element having a size capable of sufficiently capturing the light is required, so that the size of various optical systems included in a liquid crystal projector or the like increases. This also leads to an increase in the size of the device incorporating the light source device.

On the other hand, if the parabolic reflector is not made large, it becomes difficult to receive all the light from the lamp light-emitting unit 3 by the parabolic reflector, and the light utilization efficiency deteriorates. Therefore, as long as a parabolic reflector is used, it is difficult to simultaneously achieve miniaturization of the system and improvement of the light use efficiency.

The light source device 1B having the structure shown in FIG.
Since a parabolic reflector is not used, the size of the system can be reduced, and the diameter of the emitted light beam can be reduced. However, the light component returned to the lamp light emitting unit 3 by the spherical reflecting mirror 35 is attenuated by at least 85% due to reflection on the light emitting unit surface. The light emitted from the lamp light emitting section 3 has a donut-shaped (annular) light emission distribution centered on the lamp optical axis L. Therefore, the available light flux is limited by the numerical aperture (NA) of the condenser lens 36 and the spherical reflecting mirror 35. Therefore, in the light source device 1B having the configuration shown in FIG. 4, it is difficult to effectively use the light from the lamp light emitting unit 3B.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to improve the light use efficiency, reduce the size of the system, reduce the diameter of the emitted light,
Another object of the present invention is to propose a light source device that can improve the degree of parallelism of emitted light.

[0011]

A light source device according to the present invention has a lamp, a condenser lens, a reflecting mirror, and a photosynthesis element. The condenser lens is composed of a plurality of condenser lens elements, and these condenser lens elements are arranged concentrically around the lamp optical axis so as to surround the light emitting portion of the lamp. The reflector includes a number of reflector elements corresponding to each condenser lens element, and each reflector element reflects a light beam emitted from the corresponding condenser lens element in a lamp optical axis direction of the lamp. It is arranged as follows.
Further, the light combining element combines the light flux reflected by each reflecting mirror element and traveling in the lamp optical axis direction into a single light flux.

In the light source device of the present invention, the divergent light from the lamp light-emitting portion is efficiently taken into the plurality of condensing lens elements surrounding the light-emitting portion, and the plurality of light beams radiate in the direction perpendicular to the lamp optical axis. It is converted into a luminous flux. These light beams are reflected by the corresponding reflecting mirror elements in the direction of the lamp optical axis. The plurality of light beams that are reflected and travel in the lamp optical axis direction are combined into a single light beam by a light combining element disposed in front.

As described above, in the light source device according to the present invention, the light emitted from the lamp light emitting portion is not returned to the lamp light emitting portion again. In addition, almost all of the light emitted from the lamp light-emitting unit is taken into the condenser lens and can be used as emitted light.
Therefore, light use efficiency can be improved. Further, since there is no need to use a large parabolic reflector, the size of the system can be reduced, and the diameter of the emitted light does not increase. Furthermore, the degree of parallelism of the light emitted from the light source device can be increased.

Here, the light combining element may be a single or a plurality of condensing lenses arranged on the front surface in the lamp optical axis direction with respect to the reflecting mirror element. Alternatively, the photosynthesis element may be composed of a number of condenser lenses corresponding to the number of the reflecting mirror elements. In this case, each condenser lens may be arranged in front of the corresponding reflecting mirror element in the lamp optical axis direction.

On the other hand, in the above configuration, the light beams reflected by the respective reflecting mirror elements are combined into a single light beam using a light combining element such as a condenser lens. Alternatively, by adjusting the direction of the reflecting surface of the reflecting mirror element or by making the reflecting surface a parabolic reflecting surface or the like, the reflecting mirror element can also be used as a photosynthetic element. In this case, each light beam reflected by each reflecting mirror element goes on the extension of the lamp optical axis and is combined into a single light beam.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a light source device according to the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of the light source device of this embodiment. Describing with reference to this figure, the light source device 1 of the present example includes a light source lamp 2, four condenser lenses 3 (1) to 3 (4),
It has four reflecting mirrors 4 (1) to 4 (4) and four condenser lenses 5 (1) to 5 (4) as photosynthetic elements.

The four condenser lenses 3 (1) to 3 (4)
In this example, they have the same shape and the same dimensions, and are arranged concentrically around the light source lamp optical axis L1 so as to surround the spherical light emitting portion 2a of the light source lamp 2. Each of the condenser lenses 3 (1) to 3 (4) has an optical axis of
The lamps are arranged to extend radially at 90-degree intervals on a plane perpendicular to the optical axis L1 with the lamp optical axis L1 as a center.

The four reflecting mirrors 4 are placed so as to surround the four condensing lenses 3 (1) to 3 (4) arranged in a cylindrical shape.
(1) to (4) are arranged. Each reflecting mirror 4 (1)
4 (4) have the same shape and the same dimensions in this example, and their reflection surfaces 4a have a trapezoidal shape in which the front is inclined away from the lamp optical axis and the front is wide. Light beams emitted from the respective condenser lenses 3 (1) to 3 (4) are reflected by the corresponding reflecting mirrors 4 (1) to 4 (4) and travel in a direction parallel to the lamp optical axis L1. .

Four condenser lenses 5 as photosynthesis elements
(1) to 5 (4) are arranged in front of the reflecting mirrors 4 (1) to 4 (4) in the lamp optical axis direction. The directions of the condenser lenses 5 (1) to 5 (4) are set so that the focal positions are the same. Each reflector 4
The light beams reflected by (1) to 4 (4) are combined into a single light beam after passing through each of the condenser lenses 5 (1) to 5 (4).

In the light source device 1 having this configuration, the diverging light from the spherical light emitting portion 2a of the lamp is efficiently taken into the four condensing lenses 3 (1) to 3 (4) surrounding the light. Good light utilization efficiency.

Further, a single light beam having a small diameter can be obtained by the four condenser lenses 5 (1) to 5 (4) as the light combining elements. Therefore, unlike the case of using a large parabolic reflector, the diameter of the light emitted from the light source device does not increase, and the parallelism of the light emitted from the light source device can be increased.

FIG. 2 shows a schematic configuration of an illumination device provided with a light source device according to a modification of the light source device of FIG. The light source device 10 shown in this figure has the same configuration as the above light source device 1 except that a single condenser lens 5A is used as a light combining element. Therefore, corresponding parts are denoted by the same reference numerals, and description thereof will be omitted.

The illustrated lighting device 20 includes a light source device 10,
It has a rod lens 21 through which a focused light beam obtained from the light source device 10 passes, and a collimating lens optical system 22 arranged on the exit side of the rod lens 21. By using the illumination device 20, a small-diameter parallel light beam having high parallelism and an averaged light intensity distribution can be obtained as illumination light.

(Other Embodiments) In the light source device of FIG. 1, four condensing lenses 3 (1) to 3 (4) are used, but the number of condensing lenses can be three, and And five or more. In this case, a reflecting mirror may be arranged corresponding to each condenser lens.

A condenser lens 5 as a photosynthesis element
(1) to 5 (4), omitting 5A, and reflecting mirrors 4 (1) to
4 (4) may be provided with a photosynthetic function. In this case, the direction and / or shape of the reflecting surface of each reflecting mirror may be changed. For example, by adopting a parabolic reflection surface or the like as the reflection surface, it is possible to converge the respective reflected light beams at one point on the extension of the lamp optical axis and combine them into a single light beam.

[0027]

As described above, in the light source device of the present invention, since a plurality of condenser lenses are arranged so as to surround the lamp light emitting portion, the efficiency of using the divergent light from the lamp can be improved. Light beams radially emitted from the respective condenser lenses are combined via a reflecting mirror and a photosynthetic element to form a single small-diameter light beam. Alternatively, the light is reflected and combined by a reflector having a light combining function to form a single small-diameter light beam.

As described above, according to the present invention, the use efficiency of the divergent light of the light source lamp can be increased without using a large-diameter reflector or the like. In contrast, the emitted light diameter does not increase. Therefore, by using the light source device of the present invention, the optical system can be manufactured in a small size and at low cost.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a light source device to which the present invention is applied.

FIG. 2 is a schematic configuration diagram illustrating an example of an illumination device in which a modified example of the light source device of FIG. 1 is incorporated.

FIG. 3 is a schematic cross-sectional configuration diagram of a light source device using a conventional parabolic reflector.

FIG. 4 is a schematic configuration diagram of a light source device using a conventional spherical reflecting mirror and a condenser lens.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source device 2 Light source lamp 2a Light emitting part 3 (1) -3 (4) Condensing lens (condensing lens element) 4 (1) -4 (4) Reflecting mirror (reflecting mirror element) 5 (1) -5 ( 4) 5A condenser lens (photosynthesis element) 10 light source device 20 illumination device 21 rod lens 22 collimating optical system

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[Procedure amendment]

[Submission date] May 21, 1999 (1999.5.2
1)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

Claims (4)

[Claims] 1. A condensing lens comprising a lamp, a condensing lens, a reflecting mirror, and a photosynthesis element, wherein the condensing lens comprises a plurality of condensing lens elements,
These condensing lens elements are arranged concentrically around the lamp optical axis so as to surround the light emitting portion of the lamp. The reflecting mirrors are provided in a number corresponding to each condensing lens element. And each reflecting mirror element is arranged so as to reflect a light beam emitted from the corresponding condensing lens element in the lamp optical axis direction of the lamp, and the light combining element is reflected by each reflecting mirror element. A light source device for combining light beams directed toward the lamp optical axis into a single light beam. 2. The light source device according to claim 1, wherein the light combining element is a single or a plurality of condensing lenses disposed on a front surface of the reflecting mirror element in a lamp optical axis direction. 3. The light combining element according to claim 1, wherein the light combining element includes a number of condenser lenses corresponding to the number of the reflecting mirror elements, and each of the condensing lenses is arranged in a lamp optical axis direction with respect to the corresponding reflecting mirror element. A light source device, which is disposed forward. 4. A light source comprising: a lamp; a condenser lens; and a reflector, wherein the condenser lens comprises a plurality of condenser lens elements;
These condensing lens elements are arranged concentrically around the lamp optical axis so as to surround the light emitting portion of the lamp. The reflecting mirrors are provided in a number corresponding to each condensing lens element. And each reflecting mirror element reflects a light beam emitted from the corresponding condensing lens element toward a point on an extension of the lamp optical axis of the lamp, and is reflected by each of the reflecting mirror elements. A light source device characterized in that each of the divided light beams is combined into a single light beam.