JP2006113085A - Light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device excellent in usability by reducing the variation of the wavelength components and the light quantity distribution of emitted light. <P>SOLUTION: The light source device 10 has a 1st light source 12, a 2nd light source 14, an outside reflector 16, an inside reflector 18, a 1st condensing lens 20 and a 2nd condensing lens 22. The reflection surface of the outside reflector 16 is formed as a parabolic reflection surface 1606 having an optical axis O1 (center axis) and a focus 1608 positioned on the optical axis O1 and recessed forward. The inside reflector 18 has a reflection surface to reflect and diffuse the light condensed on the optical axis O1 inside the main body of the outside reflector by the 1st condensing lens 20 to the reflection surface of the outside reflector 16, and the reflection surface is constituted as an elliptical reflection surface 1802 projecting backward. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light source device.

There is a projection display device (projector) that forms an image by projecting a light beam on a screen. As such a projection display device, a light source device, an optical system that separates a light beam emitted from the light source device into a plurality of light beams having different wavelengths, and each separated light beam is combined into one light beam for image formation. And an image forming unit that emits light.
Conventionally, as the light source device, a high-pressure mercury lamp that is high in temperature during operation is often used, and a cooling means for cooling the high-pressure mercury lamp is required, which is disadvantageous for downsizing and cost reduction.
Therefore, a light source device using a semiconductor laser has been proposed (see, for example, Patent Document 1).
As shown in FIG. 100, this light source device absorbs the laser diode 1 that emits ultraviolet laser light forward, and the laser light that is disposed in front of the laser diode 1 and is collected by the condenser lens 5, and spontaneously emits light. The phosphor 6 that emits incoherent light and the laser light (ultraviolet rays) that are disposed in front of the phosphor 6 and pass through the phosphor 6 are reflected by the phosphor 6, but spontaneously emitted light (light other than ultraviolet rays) is transmitted. And, in other words, an ultraviolet reflecting mirror 7 having an optical film having a characteristic of selectively transmitting or reflecting light according to wavelength, and spontaneous emission light emitted from the phosphor 6 is reflected as parallel light 8. And a visible light reflecting mirror 9 having an object reflecting surface 9a.
JP 2003-295319 A

However, in the prior art, when the phosphor 6 absorbs the laser light output from the laser diode 1 and emits it as spontaneous emission light, a loss of output occurs due to conversion from the laser light to spontaneous emission light. . In addition, spontaneous emission light emitted from the phosphor 6 is collected by the condenser lens 5, but its emission point has a spread within the surface on which the phosphor 6 is applied, and is emitted from the visible light reflecting mirror 9. Even if the phosphor 6 is arranged at the focal point of the object reflecting surface 9a, the light emitted from a position away from the focal point is not output as the parallel light 8 and may not be effectively used as light for projection illumination. .
The present invention has been made in view of such circumstances, and an object thereof is to efficiently output, for example, a beam-shaped light beam output from a light emitting diode or the like as an illumination light beam larger than the cross-sectional area of the beam-shaped light beam. An object of the present invention is to provide a light source device that can be used and has excellent usability.

  In order to achieve the above object, a light source device of the present invention is a light source device including an outer reflector and a first light source disposed on an optical axis of the outer reflector, and the light source device is arranged at the rear end of the outer reflector. An opening is provided on the optical axis, and the first light source is disposed behind the outer reflector so as to face the opening on the optical axis of the outer reflector, and forward of the first light source on the optical axis. A first condensing lens for condensing light emitted from the first light source is disposed, and the light collected by the first condensing lens on the optical axis inside the outer reflector is used as the outer reflector. An inner reflector having a reflecting surface for reflecting and diffusing to the reflecting surface of the inner reflector is disposed, and light diffused by the reflecting surface of the inner reflector is reflected by the reflecting surface of the outer reflector. Characterized in that it is configured to emit a parallel light parallel to the optical axis in front.

According to the light source device of the present invention, the light emitted from the first light source is condensed by the first condenser lens, diffused by the reflection surface of the inner reflector, and reflected by the reflection surface of the outer reflector. It is emitted forward as parallel light parallel to the optical axis.
Therefore, unlike the prior art, the phosphor 6 that absorbs laser light and emits it as spontaneous emission light is not used, and the light emitted from the first light source is converted into parallel light using only the condenser lens and the reflecting surface. Since it is output, no output loss due to light conversion or the like occurs, which is advantageous in realizing a highly efficient light source device.

  For example, for the purpose of realizing a light source device that can efficiently output a beam-shaped light beam output from a light emitting diode or the like as a light beam for illumination larger than the cross-sectional area of the beam-shaped light beam, the light source is emitted from the first light source. The light is condensed by the first condenser lens, diffused by the reflection surface of the inner reflector, reflected by the reflection surface of the outer reflector, and emitted as parallel light parallel to the optical axis in front of the first light source.

Embodiments of a light source device according to the present invention will be described below with reference to the drawings.
In this embodiment, a case where the light source device is incorporated in a projection display device will be described.
1 is a configuration diagram illustrating a main part of a projection display device according to a first embodiment, FIG. 2 is a cross-sectional perspective view of the light source device 10 according to the first embodiment, FIG. 3 is a perspective view of the light source device 10 according to the first embodiment, and FIG. FIG. 5 is a cross-sectional view of the light source device 10 in the first embodiment, FIG. 5 is an explanatory diagram of the light source device 10 in the first embodiment, and FIG. 6 is an explanatory diagram of the principle of the outer reflector and the inner reflector of the light source device 10 in the first embodiment.

As shown in FIG. 1, the projection display device 100 includes three light source devices 10, three liquid crystal panels 50, a cross dichroic prism 60, a projection lens (not shown), and the like according to the present invention.
One of the three light source devices 10 emits a red (R) light beam to the corresponding liquid crystal panel 50, and the other one of the three light source devices 10 supports a green (G) light beam. The remaining one of the three light source devices 10 is configured to emit a blue (B) light beam to the corresponding liquid crystal panel 50.
Each liquid crystal panel 50 displays image information of the corresponding three colors of red (R), green (G), and blue (B), so that the light beams emitted from the respective light source devices 10 pass therethrough. It is configured.
The cross dichroic prism 60 is configured to combine the three light beams transmitted through the three liquid crystal panels 50 into one light beam A and project it as a color image on the screen via the projection lens.

As shown in FIGS. 2 to 4, each light source device 10 includes a first light source 12, a second light source 14, an outer reflector 16, an inner reflector 18, a first condenser lens 20, a second condenser lens 22, and the like. have.
The outer reflector 16 has a main body 1602 formed in an open shape in the front, and a reflection surface is formed on the inner surface of the main body 1602, and the reflection surface is formed on the optical axis O1 (central axis) and the optical axis O1. It is formed as a concave parabolic reflecting surface 1606 in the front having a focal point 1608 (corresponding to the third focal point in the claims).
At the rear end of the main body 1602 of the outer reflector 16, an opening 1604 is provided on the optical axis O1.
A cylindrical body 17 is connected to the rear end of the main body 1602 of the outer reflector 16 so as to face the opening 1604.
The cylindrical body 17 includes a cylindrical wall portion 1702 coaxial with the optical axis O1, and an end surface wall 1704 connected to the rear end of the cylindrical wall portion 1702. The cylindrical body 17 is provided at a position of the end surface wall 1704 through which the optical axis O1 passes. Has a hole 1706 formed therethrough.

The first light source 12 is disposed behind the outer reflector 16 on the optical axis O1 of the outer reflector 16 so as to face the opening 1604, and any one of red (R), green (G), and blue (B) light. It is comprised by the light emitting diode (LED) which radiates | emits.
Specifically, the first light source 12 is accommodated and held in a space portion 17A that is open in the front formed in the cylindrical body 17, and the light emission point is located on the optical axis O1 and emits light forward. It is arranged to do.
More specifically, as shown in FIGS. 3 and 4, the first light source 12 includes a shaft portion 1202 having a smaller outer diameter than the hole 1706 of the rear end surface 1704 of the cylindrical body 17, and a shaft portion. And a light emitting portion 1604 that is attached to the front end of 1202 and emits light.
The first light source 12 is positioned by an adjustment jig (not shown) so that the light emitting point of the light emitting unit 1604 and the optical axis O1 coincide with the shaft 1202 inserted through the hole 1706. The gap between the outer periphery of the shaft portion 1202 and the inner periphery of the hole 1704 is filled with an adhesive, and the adhesive is cured to be attached to the cylindrical body 17.

As shown in FIG. 6, the first condenser lens 20 is disposed behind the outer reflector 16 on the optical axis O <b> 1 and in front of the first light source 12 so as to face the opening 1604.
The 1st condensing lens 20 condenses the light emitted from the 1st light source 12, and has the focus 2002 which converges the said light.
As shown in FIGS. 2 and 4, the first condenser lens 20 is disposed in the space portion 17 </ b> A via a stay 1620 connected to an inner portion of the main body 1602 of the outer reflector 16.

The inner reflector 18 has a reflecting surface that reflects and diffuses the light collected by the first condenser lens 20 on the optical axis O1 inside the main body 1202 of the outer reflector 12 to the reflecting surface of the outer reflector 16; This reflection surface is configured as an elliptical reflection surface 1802 that is convex rearward.
In the present embodiment, the inner reflector 18 is disposed near the rear end of the outer reflector 16, and the inner reflector 18 is disposed at the inner portion of the main body 1602 of the outer reflector 16 as shown in FIGS. 2 and 4. It is disposed through a connected stay 1620.
The outline of the inner reflector 18 as viewed from the direction of the optical axis O <b> 1 is formed with a size smaller than that of the first condenser lens 20.
As shown in FIG. 6, the elliptical reflecting surface 1802 includes a first focal point 1804 and a second focal point 1806 that are located on the optical axis O <b> 1 and opposite to the first light source 12 with respect to the elliptical reflecting surface 1802. And the first focal point 1804 is positioned in front of the second focal point 1806. In FIG. 6, the elliptical reflection surface 18 is indicated by a solid line, and a broken line continuous with the solid line indicates an elliptical virtual line including the elliptical reflection surface 1802.
The elliptical reflecting surface 1802 is configured such that the first focal point 1804 coincides with the focal point 2002 of the first condenser lens 20 and the second focal point 1806 coincides with the focal point 1608 of the parabolic reflecting surface 1606 of the outer reflector 16. ing.
The parabolic reflection surface 1606 and the elliptical reflection surface 1802 are arranged such that the light emitted from the first light source 12 is collected by the first condenser lens 20 and diffused by the elliptical reflection surface 1802 of the inner reflector 18, and then the outer reflector. It is configured to be reflected by 16 parabolic reflecting surfaces 1806 and emitted as parallel light parallel to the optical axis O 1 in front of the first light source 12.

The second light source 14 is a light source different from the first light source 12 and is disposed in the main body 1606. More specifically, the second light source 14 is disposed on the optical axis O1 in front of the inner reflector 18 and close to the inner reflector 18, and emits light having the same wavelength as that of the first light source 12 toward the front. It consists of a light emitting diode.
The second light source 14 is formed in a size smaller than the outline of the inner reflector 18 when viewed from the optical axis O1 direction.
As shown in FIGS. 2 and 4, the second light source 14 is disposed via a stay 1620 connected to an inner portion of the main body 1602 of the outer reflector 16.

The second condenser lens 22 is disposed in front of the second light source 14 so as to emit light from the second light source 14 forward as parallel light parallel to the optical axis O1.
The second condenser lens 22 is formed in a size larger than the contour of the second light source 14 when viewed from the optical axis O1 direction.
As shown in FIGS. 2 and 4, the second light source 14 is disposed via a stay 1620 connected to an inner portion of the main body 1604 of the outer reflector 16.

Next, the function and effect will be described.
The light emitted from the first light source 12 is collected by the first condenser lens 20, diffused by the elliptical reflecting surface 1802 of the inner reflector 18, and reflected by the parabolic reflecting surface 1806 of the outer reflector 16. Is emitted as parallel light parallel to the optical axis O1. This parallel light is emitted so as to pass through a region extending in an annular shape excluding a circular region including the outline of the inner reflector 18 with the optical axis O1 as the center when viewed from the optical axis O1 direction.
The light emitted from the second light source 14 is collected by the second condenser lens 22, emitted forward as parallel light, and emitted so as to pass through a circular region including the outline of the inner reflector 18. .
Therefore, according to the present embodiment, the light emitted from the first light source 12 and collected by the first condenser lens 20 is diffused by the elliptical reflecting surface 1802 of the inner reflector 18 to be parabolic reflecting surface of the outer reflector 16. The light is reflected at 1606 and emitted in front of the first light source 12 as parallel light parallel to the optical axis O1.
That is, the light emitted from the first condenser lens 20 so as to be condensed at the second focal point 1806 of the elliptical reflecting surface 1802 is reflected by the elliptical reflecting surface 1802, but the reflected light is as shown in FIG. The light is virtually diffused from the elliptical reflecting surface 1802 as light of a path output from the first focus 1804. Since the first focal point 1804 of the elliptical reflecting surface 1802 and the focal point 1608 of the parabolic reflecting surface 1806 of the outer reflector 16 are arranged to coincide with each other, the light diffused from the elliptical reflecting surface 1802 is parabolically reflected. The light is reflected by the surface 1806 and output as parallel light.
As described above, the light emitted from the first light source 12 is collected by the first condenser lens 20, and the collected light is reflected by the inner reflector 18 and the outer reflector 16 to be emitted forward as parallel light. In addition, the light emitted from the first light source 12 can be efficiently converted into parallel light, and can be expanded to a wider range by using two reflecting surfaces of the inner reflector 18 and the outer reflector 16. This is advantageous for emitting parallel light, and is advantageous for ensuring the quality of an image formed on the screen by the projection display device 100.
Further, according to the present embodiment, the light emitted from the first light source 12 is an annular shape excluding a circular region including the outline of the inner reflector 18 with the optical axis O1 as the center when viewed from the optical axis O1 direction. Therefore, the amount of light in the circular region including the outline of the inner reflector 18, in other words, the region around the optical axis O <b> 1 is reduced. However, the light emitted from the second light source 14 and collected by the second condenser lens 22 passes through a circular region including the outline of the inner reflector 18 as parallel light in front of the second light source 14. Since the light is emitted, it is possible to prevent a decrease in the amount of light in the portion including the contour of the inner reflector 18 when viewed from the direction of the optical axis O1, which is advantageous in achieving a uniform light amount distribution. This is advantageous in ensuring the quality of the image formed on the top.
Further, in this embodiment, since the light emitting diodes are used as the first and second light sources 12 and 14, since there is little heat generation, it is not necessary to provide a cooling means, so that the size and cost can be reduced. It will be advantageous.

Next, Example 2 will be described.
The difference between the second embodiment and the first embodiment is mainly the configuration of the inner reflector.
FIG. 7 is an explanatory diagram of the light source device 10 according to the second embodiment. In the following description, parts and members similar to those in the first embodiment are denoted by the same reference numerals.
As shown in FIG. 7, the first condenser lens 24 is configured to condense light from the first light source 12 that passes through the first condenser lens 24 into parallel light parallel to the optical axis O1. ing.
The outer reflector 16 has a reflecting surface, and this reflecting surface is a parabolic reflecting surface 1606 that is concave in the rear and has a first focal point 1630 located in front of the first condenser lens 24, as in the first embodiment. It is configured.
The inner reflector 22 has a reflective surface, which comprises a forwardly concave parabolic reflective surface 2202 having a second focal point 2204 that coincides with the first focal point 1630.
The outline of the inner reflector 22 as viewed from the direction of the optical axis O <b> 1 is formed with substantially the same size as the first condenser lens 24.
The parabolic reflection surface 1606 of the outer reflector 16 and the parabolic reflection surface 2202 of the inner reflector 22 are arranged such that light emitted from the first light source 12 is collected by the first condenser lens 20 and parabolic reflection of the inner reflector 22. After being diffused by the surface 2202, the light is reflected by the parabolic reflection surface 1806 of the outer reflector 16 and emitted to the front of the first light source 12 as parallel light parallel to the optical axis O 1.
Similarly to the first embodiment, the second light source 14 is disposed on the optical axis O1 in front of the inner reflector 22 and in the vicinity of the inner reflector 22, and the second light source 14 includes the first light source 12 and the second light source 14. The light emitting diode is configured to emit light of the same wavelength toward the front.
The second light source 14 is formed with a size smaller than the contour of the inner reflector 22 when viewed from the direction of the optical axis O1.
The second condenser lens 22 is arranged in front of the second light source 14 so as to emit the light from the second light source 14 forward as parallel light parallel to the optical axis O1, and the second condenser lens 22 is It is formed in a size larger than the contour of the second light source 14 when viewed from the optical axis O1 direction.

According to such a configuration, the light emitted from the first light source 12 is condensed by the first condenser lens 24 and diffused by the parabolic reflection surface 2202 of the inner reflector 22 as in the first embodiment. The light is reflected by the parabolic reflection surface 1806 of the reflector 16 and is emitted in front of the first light source 12 as parallel light parallel to the optical axis O1. This parallel light is emitted so as to pass through a region extending in an annular shape excluding a circular region including the outline of the inner reflector 18 with the optical axis O1 as the center when viewed from the optical axis O1 direction.
The light emitted from the second light source 14 is collected by the second condenser lens 22, emitted forward as parallel light, and emitted so as to pass through a circular region including the outline of the inner reflector 18. .
Therefore, the second embodiment can achieve the same effects as the first embodiment, which is advantageous in securing the quality of the image formed on the screen.
Further, since light emitting diodes are used as the first and second light sources 12 and 14, since there is little heat generation, there is no need to provide a cooling means, which may be advantageous for downsizing and cost reduction. The same as in the first embodiment.

Next, Example 3 will be described.
The third embodiment is different from the first embodiment in that the second light source and the second condenser lens are not provided.
FIG. 8 is an explanatory diagram of the light source device 10 according to the third embodiment.
As shown in FIG. 8, in Example 3, since the second light source 14 and the second condenser lens 22 are omitted, a circular region including the outline of the inner reflector 18, in other words, a region around the optical axis O1. The amount of light decreases.
However, by providing an optical system including two fly-eye lenses and a condensing lens in front of the light source device 10 along the optical axis O1, the luminous flux divided by the fly-eye on the irradiated surface of the liquid crystal panel 50 or the like. The light emitted from the parabolic reflection surface 1606 of the outer reflector 16 of the optical device 10 is distributed by the optical system so that the light quantity is superimposed, thereby making it possible to make the light quantity distribution uniform.
Therefore, by arranging such an optical system between the optical device 10 shown in FIG. 1 and the incident surface of the liquid crystal panel 50, light with a uniform light amount distribution can be incident on the incident surface of the liquid crystal panel 50. it can.
In the third embodiment as well, as in the first embodiment, the variation in the wavelength component of the light and the variation in the light amount distribution are suppressed, and the light amount distribution is made uniform, so that the projection type display device 100 can be placed on the screen. This is advantageous in ensuring the quality of the formed image.
In addition, since a light emitting diode is used as the first light source 12, since there is little heat generation, there is no need to provide a cooling means, which is advantageous for downsizing and cost reduction as in the first embodiment. It is.

Next, Example 4 will be described.
The fourth embodiment is different from the second embodiment in that the second light source and the second condenser lens are not provided.
FIG. 9 is an explanatory diagram of the light source device 10 according to the fourth embodiment.
As shown in FIG. 9, in Example 4 as well as Example 3, since the second light source 14 and the second condenser lens 22 are omitted, a circular region including the outline of the inner reflector 18, in other words, light The amount of light in the area around the axis O1 decreases.
However, it is emitted from the parabolic reflection surface 1606 of the outer reflector 16 of the optical device 10 by providing an optical system including two fly-eye lenses and a condensing lens in front of the light source device 10 along the optical axis O1. The light is distributed by the optical system, thereby making it possible to make the light quantity distribution uniform.
Therefore, by arranging such an optical system between the optical device 10 shown in FIG. 1 and the incident surface of the liquid crystal panel 50, light with a uniform light amount distribution can be incident on the incident surface of the liquid crystal panel 50. it can.
Accordingly, in the fourth embodiment, similarly to the third embodiment, a light source device having a high light utilization rate is realized, and the light amount distribution is made uniform so that an image formed on the screen in the projection display device 100 can be obtained. This is advantageous in ensuring quality.
In addition, since a light emitting diode is used as the first light source 12, since there is little heat generation, there is no need to provide a cooling means, which is advantageous for downsizing and cost reduction as in the third embodiment. It is.

  In addition, although each Example demonstrated the case where the light source device 10 was integrated in the projection type display apparatus 100, the light source device 10 is not limited to what is integrated in the projection type display apparatus 100, Other various apparatuses, such as illumination equipment. Of course, it can be applied to various devices.

1 is a configuration diagram illustrating a main part of a projection display device in Embodiment 1. FIG. 1 is a cross-sectional perspective view of a light source device 10 in Embodiment 1. FIG. 1 is a perspective view of a light source device 10 in Embodiment 1. FIG. It is sectional drawing of the light source device 10 in Example 1. FIG. It is explanatory drawing of the light source device 10 in Example 1. FIG. It is principle explanatory drawing of the outer side reflector of the light source device 10 in Example 1, and an inner side reflector. It is explanatory drawing of the light source device 10 in Example 2. FIG. It is explanatory drawing of the light source device 10 in Example 3. FIG. It is explanatory drawing of the light source device 10 in Example 4. FIG. It is explanatory drawing of the conventional light source device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Light source device, 12 ... 1st light source, 14 ... 2nd light source, 16 ... Outer reflector, 1604 ... Aperture, 18 ... Inner reflector, 20 ... 1st condensing lens, 22 ... ... second condenser lens, O1 ... optical axis.

Claims (11)

A light source device comprising an outer reflector and a first light source disposed on the optical axis of the outer reflector,
An opening is provided on the optical axis at the rear end of the outer reflector,
The first light source is disposed behind the outer reflector, facing the opening on the optical axis of the outer reflector,
A first condenser lens for condensing the light emitted from the first light source on the optical axis and in front of the first light source;
An inner reflector having a reflecting surface that reflects and diffuses the light collected by the first condenser lens on the optical axis inside the outer reflector is disposed on the reflecting surface of the outer reflector,
The light diffused by the reflecting surface of the inner reflector is reflected by the reflecting surface of the outer reflector and is configured to be emitted as parallel light parallel to the optical axis in front of the outer reflector.
A light source device characterized by that.   The light source device according to claim 1, wherein the first condenser lens is disposed behind the outer reflector so as to face the opening.   The light source device according to claim 1, wherein the inner reflector is disposed near a rear end of the outer reflector. The first condenser lens has a focal point for converging light from the first light source passing through the first condenser lens;
The reflective surface of the inner reflector has an elliptical reflection that is convex rearward and has a first focal point and a second focal point that are located on the opposite side to the first light source with respect to the reflective surface inside the outer reflector. The first focal point is located at a position ahead of the second focal point,
The reflection surface of the outer reflector is configured with a rear-side concave parabolic reflection surface having a third focal point,
2. The light source device according to claim 1, wherein the first focal point coincides with a focal point of the first condenser lens, and the second focal point coincides with the third focal point.   The light source device according to claim 4, wherein an outline of the inner reflector viewed from the optical axis direction is formed to be smaller than the first condenser lens. The first condenser lens is configured to condense light from the first light source that passes through the first condenser lens into parallel light;
The reflection surface of the outer reflector is configured with a concave concave parabolic reflection surface having a first focal point located at a front location of the first condenser lens,
2. The light source device according to claim 1, wherein the reflection surface of the inner reflector is configured by a concave parabolic reflection surface having a second focal point that coincides with the first focal point.   The light source device according to claim 6, wherein an outline of the inner reflector viewed from the optical axis direction is formed to have substantially the same size as the first condenser lens.   The light source device according to claim 1, wherein the first light source is a light emitting diode.   A second light source different from the first light source that emits light toward the front is disposed on the optical axis in front of the inner reflector, and the second light source is disposed in front of the second light source. The light source device according to claim 1, further comprising: a second condenser lens that emits light from the front as parallel light parallel to the optical axis.   The light source device according to claim 9, wherein the second light source is disposed at a location close to the inner reflector. The light source device according to claim 9, wherein the second light source is a light emitting diode, and is configured to emit light having the same wavelength as that of the first light source.

Images