JP2012164639A - Lighting device and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device using an LED element as a light source, in which light utilization efficiency is improved without making the device large in size and bright illumination can be obtained with a compact structure.SOLUTION: The lighting device has an LED element 1, an elliptical reflector 5, and a flat mirror 4, and light reflected by the flat mirror 4 is condensed to the converging point F2'. When an axis passing the center of the LED element 1 and the converging point F2' is made a lighting system optical axis z, the elliptical reflector 5 has an opening o1 of a circular shape with a prescribed diameter having the lighting system optical axis z as a center, and is arranged directing the reflection surface of the elliptical reflector 5 toward the rear side in the lighting system optical axis z direction. Further, the flat mirror 4 is arranged on the rear side of the LED element 1, and light reflected by the elliptical reflector 5 out of the light emitted from the LED element 1 is reflected by the flat mirror 4 and passes through the opening o1, and is condensed toward the converging point F2'.

Description

  The present invention relates to an illuminating device and an illuminating system, and more specifically to an illuminating device that generates illuminating light using an LED element, and an illuminating system suitable for illumination of a projection display device.

  As an illumination device used for illumination of a projection display device, there is one using an LED element as a light source. The light emitted from the LED element is diffused light. Usually, the light from the LED element is condensed using a reflector, a condensing lens, or the like, so that the light utilization efficiency is improved and a bright projection image is obtained.

Regarding such an illuminating device, for example, Patent Document 1 includes a light source using an LED element, an elliptical mirror, and a collimator lens, and at the positions of the first focal point and the second focal point in the elliptical mirror, An illumination device is disclosed in which an object point and an image point of a collimator lens are arranged.
In this illuminating device, of the light emitted from the LED element, the light near the apex direction of the LED element (near the illumination system optical axis direction) is condensed by one condenser lens. Moreover, the light near the outer peripheral direction of the LED element is reflected by an elliptical reflector (rotating body) and condensed at the same position as the condensing point by the condenser lens.

  Patent Document 2 discloses an illumination optical system that includes a light source and a reflector, and includes a substantially spherical circular reflector that returns light emitted from the light source to the outside of the illuminated area without going through the reflector. Has been. This illumination optical system is provided with a plane mirror or a substantially spherical sub-reflector that returns light illuminating the outside of the illuminated area via the reflector to the light source side.

  Patent Document 3 discloses an illumination device including a spheroid mirror, a light source, a spherical mirror, and a condenser lens. The spheroid mirror lacks a reflective portion of light that irradiates light other than the illumination target. The light traveling from the light source toward the missing portion is reflected by the spherical mirror on the rear side of the missing portion when viewed from the light source, and is reflected again by the spheroid mirror on the side opposite to the missing portion to illuminate the object to be illuminated. .

  In both Patent Documents 2 and 3, among the light emitted from the light source arranged at the elliptical first focal point of the elliptical reflector, the light emitted backward is reflected by the elliptical reflector and becomes the elliptical second focal point. Condensate. Also, the light emitted toward the front of the light source (near the illumination system optical axis direction) returns to the light source once by the spherical reflector, passes through the light source, travels to the elliptical reflector, is reflected by the elliptical reflector, and is reflected at the second focal point of the ellipse. Condensate. Thereby, in the ellipse second focus, the light use efficiency is intended to be improved by increasing the component having a small light beam angle by the light emitted forward from the light source.

JP 2005-91383 A JP-A-5-264904 JP-A-6-250288

The illumination device of Patent Document 1 has a smaller size (imaging size) that is reflected by the elliptical reflector and condensed at the second focal point of the ellipse than the size (object image) of the light emitting portion of the LED element.
Here, the specification of the condensing lens is designed so that the light from the light source is transmitted and imaged at the same position as the second focal point of the ellipse. The size of the image formed by the light beam in the elliptical reflector path is considerably larger. For this reason, a considerable difference occurs in the condensing size at the elliptical second focal point (condensing point) depending on the path of the light beam, and the light use efficiency in the optical system after the condensing point is deteriorated.

  On the other hand, the illumination systems of Patent Documents 2 and 3 use a high-pressure discharge lamp as a light source, and cannot be applied to an illumination system using an LED element as a light source. This is because the light distribution of the high-pressure discharge lamp is completely different from the light distribution of the LED element light source. The state of the light distribution of the high pressure discharge lamp and the LED element light source will be described below.

FIG. 10 is a diagram schematically showing a configuration example of an illumination system using a high-pressure discharge lamp, in which 100 is a high-pressure discharge lamp, 101 is a light emitting unit, 102 is an electrode, 103 is a glass envelope, and 104 is an ellipse. It is a reflector. As shown in FIG. 6, the high-pressure discharge lamp 100 has a large light distribution S in the direction perpendicular to the illumination system optical axis z. The light distribution S represents the intensity of light emission according to the light emission direction.
Here, when the axis orthogonal to the illumination system optical axis z and passing through the light emitting unit 101 is the x-axis, the light distribution angle θ from the high-pressure discharge lamp 100 is about 50 ° at the maximum with respect to the x-axis. Such light distribution is distributed 360 ° around the z-axis.

  FIG. 11 is a diagram schematically showing the illumination system disclosed in Patent Documents 2 and 3, and shows a configuration in which an elliptical reflector 123 and a spherical reflector 124 are provided on the rear side and the front side of the high-pressure discharge lamp 120, respectively. . The light emitting part 121 of the high pressure discharge lamp 120 is disposed at the position of the elliptical first focal point F1 of the elliptical reflector 123. Further, the position of the first focus F1 also coincides with the center position of the circle of the spherical reflector 124.

  Of the light emitted from the light emitting unit 121, the light reflected by the elliptical reflector 123 is collected at the elliptical second focal point F2. The light reflected by the spherical reflector 124 disposed in front of the high-pressure discharge lamp 120 returns to the light-emitting portion 121 of the high-pressure discharge lamp 120 once, passes through the high-pressure discharge lamp 120, and is reflected again by the elliptical reflector 123. Condensed to the elliptical second focal point F2.

  Since the light emitting unit 121 is located between the pair of lamp electrodes 122 and there is no obstacle here, the light emitted from the light emitting unit 121 can be transmitted by returning the light once emitted to the light emitting unit 121, and this is reflected by the elliptical reflector. The light beam angle at the second focal point F2 can be reduced by reflecting at 123 and condensing at the second focal point F2.

FIG. 12 is a diagram schematically showing a light distribution when an LED element is used as a light source. In the figure, 110 is an LED element, and 111 is an LED element substrate.
In the example of FIGS. 10 and 11, since the high-pressure discharge lamp is used as the light source, the light utilization efficiency is improved by reflecting the light with the spherical reflector arranged in front and transmitting the high-pressure discharge lamp again to reflect it. I was doing. On the other hand, when the LED element 110 is used as the light source, the light distribution S of the LED element 110 emits completely diffuse light around the illumination system optical axis z. At this time, the light distribution angle θ with respect to the illumination system optical axis z is about 90 ° at the maximum. Such light distribution is distributed 360 ° around the z-axis.

Even when the LED element 110 having such characteristics is applied to the configuration using the high-pressure discharge lamp as shown in FIG. 11, the light reflected by the spherical reflector 124 passes through the LED element 110 provided on the LED element substrate 111. It cannot penetrate.
That is, when it is going to comprise the illuminating device which uses a LED element as a light source, the illuminating device for high pressure discharge lamps cannot be applied. Therefore, an illuminating device having a unique configuration using an LED element as a light source is required. At this time, there is a demand for an illumination device that can perform bright illumination with improved light utilization efficiency without increasing the size of the device. In addition, since the illumination system that illuminates the projection display device includes a plurality of illumination devices as described above (usually, three for RGB), there is a compact and highly efficient light utilization system in the entire illumination system. Desired.

  The present invention has been made in view of the above circumstances, and in a lighting device using an LED element as a light source, the light utilization efficiency is improved without increasing the size of the device, thereby performing bright illumination with a compact configuration. It is an object of the present invention to provide an illuminating device which can be used, and an illumination system for illumination of a projection display device using the illuminating device.

  In order to solve the above-described problem, the first technical means of the present invention includes an LED element, an elliptic reflector made of an elliptic rotating body that reflects light emitted from the LED element, and light reflected by the elliptic reflector again. An illumination device for reflecting light reflected by the mirror member toward a condensing point, the illumination system light having an axis passing through the center of the LED element and the condensing point When the axis is an axis, the elliptical reflector includes a reflecting surface having a shape obtained by rotating at least a part of the shape of the ellipse around the illumination system optical axis, and has a circular shape with a predetermined diameter around the illumination system optical axis. And the reflective surface is disposed toward the rear side in the illumination system optical axis direction, and the mirror member is disposed on the rear side in the illumination system optical axis direction of the LED element, and the LED element. Out of the light emitted from The light reflected by the elliptical reflector is reflected by the mirror member, towards said focal point through said aperture is obtained characterized by collecting light.

  A second technical means is the first technical means, wherein the mirror member is a flat mirror having a reflective surface in a planar shape, and the LED element is disposed at a first focal position of an ellipse of the elliptical reflector, The elliptical reflector is formed in a shape for condensing the light emitted from the LED element at the second focal position of the ellipse, and the reflection surface of the mirror member is provided perpendicular to the illumination system optical axis, The condensing point is a position corresponding to a plane-symmetrical position of the second focal position when the reflecting surface of the mirror member is a symmetrical plane.

  A third technical means acts on at least a part of the light emitted from the LED element toward the inside of the opening among the light emitted from the LED element in the first or second technical means, and the condensing point. And a condensing lens for condensing the light.

  The fourth technical means is the rod that acts on at least part of the light emitted from the LED element toward the inside of the opening in the light emitted from the LED element in any one of the first to third technical means. The rod lens has a lens, and is arranged at a position where light that is reflected by the flat mirror and goes toward the condensing point is incident.

  According to a fifth technical means, in the first technical means, the mirror member has a reflecting surface formed by rotating a hyperbola formed on a surface including the illumination system optical axis around the illumination system optical axis. A hyperbolic mirror, wherein the LED element is disposed at a first focal position of the ellipse of the elliptical reflector, and the elliptical reflector is configured to condense light emitted from the LED element at a second focal position of the ellipse. In the positional relationship between the two curves and the two focal points of the hyperbola formed and forming the reflecting surface of the mirror member, the condensing point is not the first focal point close to the curve forming the reflecting surface of the mirror member. The second focal point is close to the other curve.

  According to a sixth technical means, in the fifth technical means, the reflection surface of the elliptical reflector is defined by one of the regions on both sides of the illumination system optical axis on the surface including the illumination system optical axis. A part of the elliptical shape is formed as a rotating body rotated about the illumination system optical axis, and the position of the second focal point of the ellipse forming the part of the elliptical shape is shifted from the optical axis of the illumination system. It is characterized by being.

  According to a seventh technical means, in the sixth technical means, the reflecting surface of the hyperbolic mirror is defined by one of the regions on both sides of the illumination system optical axis on the surface including the illumination system optical axis. A part of the hyperbola is formed as a rotating body that is rotated about the optical axis of the illumination system, and forms the first focal point of the hyperbola that forms part of the hyperbola and the part of the ellipse. The second focal point of the ellipse coincides with the second focal point of the hyperbola and is located on the optical axis of the illumination system.

  The eighth technical means includes the LED element substrate on which the LED element is mounted behind the mirror member in the illumination system optical axis direction in any one of the first to seventh technical means, and the LED The element is installed on an LED element base provided on the LED element substrate, and the mirror member is installed at a position for condensing the light reflected by the elliptical reflector to the condensing point through the opening. It is characterized by.

  The ninth technical means includes a plurality of illumination devices according to any one of the first to eighth technical means, and a plurality of first collections for condensing each of the light emitted from the plurality of illumination devices. An illumination system comprising: an optical lens; and a cross dichroic prism that combines light emitted from the plurality of first condenser lenses.

  A tenth technical means is characterized in that, in the ninth technical means, a second condenser lens is provided on an outgoing light path of the light synthesized by the cross dichroic prism.

  The eleventh technical means is characterized in that, in the ninth technical means, a fly-eye lens is provided on the outgoing light path of the light synthesized by the cross dichroic prism.

  According to the present invention, in an illuminating device using an LED element as a light source, by improving light utilization efficiency without increasing the size of the illuminating device, it is possible to perform bright illumination with a compact configuration, An illumination system for illuminating a projection display device using the illumination device can be provided.

It is a figure which shows the structure of one Embodiment of the illuminating device by this invention. It is a figure which shows one Embodiment of the illumination system which concerns on this invention. It is a figure which shows 2nd Embodiment of the illumination system which concerns on this invention. It is a figure which shows the structure of 2nd Embodiment of the illuminating device by this invention. It is a figure which shows the structure of 3rd Embodiment of the illuminating device by this invention. It is a figure which shows 4th Embodiment of the illuminating device by this invention. It is a figure which shows other embodiment of the illumination system which concerns on this invention, and shows the structural example of the projection type display apparatus which uses the illuminating device of 4th Embodiment. It is a figure which shows 5th Embodiment of the illuminating device by this invention. It is a figure for demonstrating the property of the hyperbola applied to a hyperbola mirror. It is a figure which shows typically the structural example of the illumination system which uses a high pressure discharge lamp. It is a figure which shows typically the illumination system shown by patent document 2, 3. FIG. It is a figure which shows typically the light distribution when a LED element is used as a light source.

FIG. 1 is a diagram showing a configuration of an embodiment of a lighting device according to the present invention, in which 1 is an LED element, 2 is an LED element base, 3 is an LED element substrate, 4 is a plane mirror, 5 is an elliptical reflector, Reference numeral 10 denotes an illumination device. The plane mirror 4 corresponds to an embodiment of the mirror member of the present invention, and is a mirror member whose reflection surface has a planar shape.
In addition, although 2 is called the LED element base, it is a means for earning a required height from the LED element substrate 3 to the light emitting part of the LED element 1, and depending on the dimensions, the LED element 1 can be formed as it is, When it cannot be formed as it is, it is necessary to increase the height to the light emitting portion of the LED element 1 by another method.
The vertical axis at the center of the LED element 1 is defined as the illumination system optical axis z, and the traveling direction of the light emitted from the LED element 1 is defined by an angle α formed from the illumination system optical axis z. The illumination system optical axis z is an axis passing through the center of the LED element and the condensing point F2 ′ where the light reflected by the plane mirror 4 is collected.

  The elliptical reflector 5 is disposed so that the center position of the LED element 1 coincides with the first focal point F1 of the elliptical reflector 5. In addition, the elliptical reflector 5 reflects light rays having a traveling direction angle α of about 15 to 90 degrees out of the light emitted from the LED elements 1 to the rear side (the LED element substrate 3 side) in the illumination system optical axis z direction. Here, the ellipsoidal reflecting surface of the ellipsoidal reflector 5 is directed rearward in the illumination system optical axis z direction, and an opening o1 is formed in the range where the angle α is 0 to 15 degrees around the illumination system optical axis z. ing. The opening o1 is a circular opening having a predetermined radius centered on the illumination system optical axis z. Accordingly, when the outer shape of the elliptical reflector 5 is seen, the opening size of the opening o2 at the rear of the elliptical reflector is larger than the opening o1 at the front of the illumination system optical axis z direction.

Of the light emitted from the LED element 1, light having an angle α of 0 to 15 degrees passes through the opening o1 and diffuses further forward. On the other hand, light having an angle α of 15 degrees or more travels in the direction of being reflected by the elliptical reflector 5 and condensed at the second focal position F2 of the ellipse.
A shape obtained by rotating the elliptical shape as described above about the illumination system optical axis z is the reflective surface shape of the elliptical reflector 5. A total reflection film is formed on the reflection surface.

The LED element 1 is installed on an LED element base 2 provided on the LED element substrate 3. A flat mirror 4 is disposed on the front side of the LED element substrate 3 (on the elliptical reflector 5 side). A reflective film is formed on the reflective surface of the plane mirror 4, and the reflective surface is perpendicular to the illumination system optical axis z.
The light reflected by the elliptic reflector 5 and traveling toward the second focal point F2 of the ellipse is reflected by the plane mirror 4 before reaching the second focal point. The light reflected by the plane mirror 4 sequentially passes through the opening o2 at the rear and the opening o1 at the front of the elliptical reflector 5, and is condensed on the illumination system optical axis z.

  This condensing position F2 ′ is a position corresponding to the second focal position F2 of the ellipse. That is, the condensing position F2 ′ is in a position symmetrical with the second focal point F2 when the reflecting surface of the plane mirror 4 perpendicular to the illumination system optical axis z is a symmetric surface. Alternatively, the condensing position F2 ′ can be said to be a point-symmetrical position with respect to the second focal point F2 when the intersection of the reflecting surface of the plane mirror 4 and the illumination system optical axis z is a symmetric point.

  Here, the position and range of the plane mirror 4 will be further described. First, the position of the plane mirror 4 in the illumination system optical axis z direction is such that light from the LED element 1 at an angle α is light from the minimum value to the maximum value of the angle α of the light reflected by the elliptical reflector 5. 4 so that all of the reflected light can pass through the front opening o 1 of the elliptical reflector 5. In this example, the minimum value of α is about 15 °, and the maximum value is about 90 °.

In the embodiment of FIG. 1, the position of the plane mirror 4 for allowing light having an angle α to pass is located behind the LED element 1 installed at the ellipse first focal point F1 in the illumination system optical axis z direction.
In this case, the LED element substrate 3 is located further rearward of the plane mirror 4, but in order to use the light effectively by widening the area of the reflection surface of the plane mirror 4, the LED element substrate 3 is provided with an LED. The element base 2 is provided, and the LED element 1 is disposed thereon. Thereby, the distance between the flat mirror 4 and the LED element 1 can be taken, and the area where the light path is blocked by the LED element is made as small as possible to increase the light utilization efficiency.

As described above, in the configuration of FIG. 1, the minimum value of the angle α of the light reflected by the elliptical reflector 5 is about 15 °, and in the illustrated state, it cannot be directly used from the LED element 1 through the opening o1. Looks like there are many rays. However, if the light emission distribution from the LED element 1 is completely diffused, the light having an angle α of up to 15 ° is only about several percent of the total light emitted from the LED element 1 if it is verified three-dimensionally. There is no loss.
Actually, by placing a rod lens at the position of the condensing point F2 ′, or by arranging an optical system after the condensing point F2 ′, light having an angle α of about 0 to 5 ° can be effectively used. . For this reason, light having an angle α other than 5 to 15 ° can be effectively used as illumination light.

  Moreover, the illuminating device of embodiment which concerns on this invention has the largest angle of the light ray condensed on a condensing point compared with the conventional illuminating device. However, even if the maximum angle is large, the condensing size can be further reduced, and the illumination magnification can be freely designed by the optical system after the condensing point, so that higher light utilization efficiency can be obtained.

  That is, the greatest feature of the illumination device according to the present invention is that the image formation size (condensation size) at the condensing point F2 ′ can be reduced with respect to the light emission size of the LED element 1 that diffuses and emits light. Although the maximum light beam angle at F2 ′ is large, the light loss can be comprehensively reduced as compared with other conventional methods, and high light utilization efficiency can be obtained.

FIG. 2 is a diagram showing an embodiment of an illumination system according to the present invention. The illumination system of the present embodiment is for application as an illumination system of a projection display device such as a DLP (Digital Light Processing) (registered trademark) projector.
The illumination system includes three illumination devices 10a to 10c having the same configuration as the illumination device 10 of FIG. The three illumination devices 10a to 10c have single-color LED elements of red (R) LED elements, green (G) LED elements, and blue (B) LED elements, respectively, as the LED elements 1a to 1c. Each of the lighting devices 10a to 10c is provided with elliptical reflectors 5a to 5c, LED element bases 2a to 2c, LED element substrates 3a to 3c, and plane mirrors 4a to 4c, respectively, and light beams reflected by the elliptical reflectors 5a to 5c. Are reflected by the plane mirrors 4a to 4c and condensed.

  The RGB light emitted from each of the illuminating devices 10a to 10c is subjected to a condensing action by the first condensing lenses 11a to 11c provided corresponding to each of the illuminating devices 10a to 10c. Then, the light enters the cross dichroic prism 12 and is synthesized by the cross dichroic prism 12. The synthesized light is condensed by the second condenser lens 13 and used as illumination light for the projection display device. For example, a rod lens is disposed after the second condenser lens 13, and then a predetermined optical system is disposed (both not shown), which is used as illumination light for illuminating a DMD (Digital Micromirror Device) of a DLP projector. can do.

  FIG. 3 is a diagram showing a second embodiment of the illumination system according to the present invention. As in FIG. 2, the illumination system of this embodiment includes three illumination devices 10 a to 10 c, first condenser lenses 11 a to 11 c provided corresponding to the illumination devices 10 a to 10 c, and a cross dichroic prism 12. The light emitted from each of the lighting devices 10a to 10c is synthesized by the cross dichroic prism 12. The illumination system of this embodiment is different from the configuration of FIG. 2 in that a fly-eye lens 14 is provided on the optical path after the cross dichroic prism 12. The light made uniform using the fly-eye lens 14 can be used as illumination light for a liquid crystal panel of a liquid crystal projector.

  As the illumination system used for the projection display device as shown in FIGS. 2 and 3, a size merits can be obtained by using a cross dichroic prism system that combines three colors of single-color LED elements. If the cross dichroic prism 12 does not allow the light beam to be incident to a certain degree of telecentricity, the light use efficiency deteriorates due to the film characteristics. Therefore, by using the first condenser lenses 11a to 11c as shown in FIG. 2 and FIG.

  2 and 3, if the focal lengths of the first condenser lenses 11 a to 11 c and the second condenser lens 13 are changed, the transmitted light of the second condenser lens 13 is condensed. The size and maximum beam angle can be changed freely. Here, when the number of lenses is minimized, lens aberration is particularly important. Therefore, an optimum aspherical shape should be designed so as to minimize lens aberration.

  A method of combining a plurality of monochromatic lights includes a sequential mirror method, which is inferior in terms of space saving compared to the cross dichroic prism method, but the sequential mirror method is advantageous in terms of cost. Therefore, the light emitted from the illumination device according to the present invention may be sequentially combined by the mirror method and used as illumination light for the projection display device.

  Further, as a lighting system for a projection display device, since the brightness efficiency per unit power is good, a configuration using the RGB single color LED element as described above is generally adopted, but a white LED element is used. You may take the structure which uses it as illumination light. In this case, a plurality of illumination devices 10 using white LED elements are provided to synthesize the light of each illumination device 10. Or you may make it obtain illumination light using the single illuminating device 10 using a white LED element.

FIG. 4 is a diagram showing a configuration of a second embodiment of the illumination device according to the present invention. In FIG. 4, 6 is a condenser lens, and other parts having the same functions as those in FIG. 1 are denoted by the same reference numerals as in FIG.
The illuminating device 10 of this embodiment arrange | positions the condensing lens 6 ahead of the illumination element optical axis z direction of the LED element 1. FIG. The light having a smaller angle α emitted from the LED element 1 is condensed at the condensing position F2 ′ by the condensing lens 6. F2 ′ is located symmetrically with the second focal point F2 when the reflecting surface of the plane mirror 4 perpendicular to the illumination system optical axis z is a symmetric surface. That is, the condensing lens 6 of the illuminating device 10 of the present embodiment acts on at least a part of the light traveling from the LED element 1 to the inside of the opening o1 of the elliptical reflector 5, and condenses it on the condensing point F2 ′. is there.

  As a specification of the condenser lens 6, the light is condensed at the condensing point F 2 ′, and the condensing size by the condensing lens 6 is reflected by the flat mirror 4 via the elliptical reflector 5 and collected at the condensing point F 2 ′. It is necessary to make it as close as possible to the light collection size and not to block the light beam that has passed through the elliptical reflector 5 with the condenser lens 6. Further, the lens aberration of the condenser lens 6 is also important, and it is necessary to cope with an aspherical lens shape.

  In the configuration according to the present embodiment, the spatial constraints around the LED element 1 such as the relationship between the LED element 1 and the flat mirror 4 are relatively loose, and the degree of freedom in design increases. In addition, the configuration of the present embodiment may be suitable when the light emitted from the LED element 1 has a large amount of light with a small light beam angle α.

  The illumination device 10 of the present embodiment can be used as an illumination system for a projection display device as shown in FIGS. In this case, an illumination system can be configured by replacing the illumination device 10 (10a to 10c) illustrated in FIGS. 2 and 3 with the illumination device 10 including the condenser lens 6 of the present embodiment.

FIG. 5 is a diagram showing a configuration of a third embodiment of the illumination device according to the present invention. In FIG. 5, reference numeral 7 denotes a rod lens, and the other parts having the same functions as those in FIG.
In the illumination device 10 of the present embodiment, the rod lens 7 is disposed in front of the LED element 1 in the illumination system optical axis z direction. Light with a small angle α (approximately α = 25 °) emitted from the LED element 1 is directly incident on the rod lens 7, and light with α = 25 to 90 ° is reflected by the elliptical reflector 5 and the plane mirror 4 to be condensed. The light is condensed at a position F2 ′. In this case, since the condensing point F2 ′ is inside the rod lens 7, the reflected light from the plane mirror 4 is acted on by the rod lens 7 before condensing on the condensing point F2 ′. Here, the reason why the condensing point F2 ′ is inside the rod lens 7 is to maximize the light utilization efficiency, and the position of the rod lens 7 is determined in consideration of matching with the illumination system after the rod lens 7. Just decide.
That is, the rod lens 7 of the illuminating device 10 of the present embodiment acts on at least a part of the light traveling from the LED element 1 to the inside of the opening o1 of the elliptical reflector 5, and is reflected by the flat mirror 4 to be a condensing point. It is arrange | positioned in the position into which the light which goes to F2 'enters.

In the case of the configuration of the present embodiment, the LED element base 2 needs to be elongated and the LED element 1 needs to be installed, but even with such a configuration, there is a space merit in the entire illumination system using the illumination device 10. May be obtained.
For example, an illumination system for illumination of a projection display device as shown in FIGS. 2 and 3 can be configured using the present illumination device 10. Here, the configuration shown in FIG. 2 can be preferably applied to a DLP projector.

  At this time, by using the illumination device 10 of the present embodiment, the first condenser lenses 11a to 11c of the illumination system are arranged after the rod lens 7 included in the illumination device 10 (10a to 10c), and the cross dichroic prism 12 is disposed. Can synthesize light of three colors. As a result, the rod lens between the cross dichroic prism 12 and the DMD can be omitted, the focal length of the second condenser lens 13 is lengthened, and the DLP projector is placed at the condensing position by the second condenser lens 13. DMDs can be placed. Therefore, although the space from the illumination device 10 to the cross dichroic prism 12 is somewhat enlarged, the space after the cross dichroic prism 12 can be reduced, and the overall illumination system can be reduced in size.

  FIG. 6 is a diagram showing a fourth embodiment of a lighting device according to the present invention. Unlike the first embodiment, the fourth embodiment includes a hyperbolic mirror 8 having a reflective surface having a hyperbolic shape instead of the flat mirror that reflects the light reflected by the elliptical reflector 5. The reflected light is focused on the second focal point of the hyperbola. The hyperbolic mirror 8 corresponds to another example of a mirror member in the present invention.

In the configuration of this embodiment, the vertical axis at the center of the LED element 1 is set as the illumination system optical axis z, and the traveling direction of the light emitted from the LED element 1 is determined from the illumination system optical axis z as in the above embodiment. Is defined by an angle α formed by Further, all of the configurations shown in FIG. 6 have a rotationally symmetric shape with respect to the illumination system optical axis z.
The elliptic reflector 5 is disposed so that the center position of the LED element 1 coincides with the first focal point F1 of the ellipse of the elliptic reflector 5. Here, the elliptical reflector 5 reflects a light beam having a light beam traveling angle α of about 15 to 90 degrees from the LED element 1 in the backward direction of the illumination system optical axis z (on the LED element substrate 3 side). In other words, when looking at the outer shape of the elliptical reflector 5, the opening size of the opening o2 at the rear of the elliptical reflector 5 is larger than the opening o1 at the front of the illumination optical axis system z direction. The ellipse shape determined in this way is rotated about the illumination system optical axis z as the reflection surface shape of the ellipsoidal reflector 5. A total reflection film is formed on the reflection surface.

The LED element 1 is installed on an LED element base 2 provided on the LED element substrate 3. A hyperbolic mirror 8 is provided on the front side (the elliptical reflector 5 side) of the LED element substrate 3. The hyperbolic mirror 8 is formed with a reflective film.
Of the light scattered and emitted from the LED element 1, light having an angle α in the range of about 15 to 90 degrees is reflected by the elliptical reflecting surface of the elliptical reflector 5 and travels in the direction of the second focal point F2 of the ellipse. The light is reflected by the hyperbolic mirror 8 before reaching the second focal point F2. The hyperbolic mirror 8 reflects all the light traveling from the elliptical reflector 5 and sequentially passes through the rear opening o2 and the front opening o1 of the elliptical reflector 5 to the condensing point F3 on the illumination system optical axis z. Collect light.

  The condensing point F3 coincides with the second focus among the two focal points of the hyperbola that forms the reflecting surface of the hyperbolic mirror 8. Here, in the positional relationship between the two curves of the hyperbola that forms the reflecting surface and the two focal points, the focal point that is close to the curve that forms the reflecting surface of the hyperbolic mirror 8 is the first focal point, and the focal point that is close to the other curve is the first focal point. When the two focal points are used, the condensing point F3 is made coincident with the second focal point of the hyperbola.

  According to the configuration of the present embodiment, since the peripheral portion of the hyperbolic mirror 8 is curved in a direction close to the LED element substrate 3 side, the light emitting portion of the LED element 1 is made somewhat higher than the LED element substrate 3. Must. The structure for this is not limited, but in this example, the LED element base 2 is provided.

  In FIG. 6, the minimum value of the angle α with respect to the illumination system optical axis z is about 15 degrees, and it seems that there are many light rays that cannot be used, but if the light emitted from the LED element 1 is completely diffused light, the angle Since the light flux with α up to 15 degrees is only about 3.4% of the total light flux, the light quantity loss is not particularly large. In fact, there is a high possibility that a rod lens is installed at the condensing point F3, and that a light beam having an angle α of about 0 to 5 degrees can be effectively used by an optical system after the condensing point F3. Therefore, assuming that the LED element 1 is a completely diffusing light source, approximately 97% of the light emitted from the LED element 1 can be used substantially having an angle α other than 5 to 15 degrees.

  The configuration of the present embodiment is larger in the maximum angle of the light beam condensed at the condensing point F3 corresponding to the second hyperbolic focus than the conventional illumination method, but the condensing size at the condensing point F3 is small. It can be made smaller. In addition, since the illumination magnification can be freely designed in the optical system after the condensing point F3, the maximum angle of the light beam at the condensing point F3 is not a problem. This is because the light collection size and the maximum angle of the light beam are in a trade-off relationship, but the light use efficiency of the configuration according to the present embodiment is high even if both are taken into consideration.

The greatest feature of this embodiment is that the image formation size (condensation size) at the condensing point F3 can be reduced with respect to the light emission size of the light diffusely emitted from the LED element 1, and Although the maximum light beam angle is large, the total light loss can be made very small compared to other methods, so that the light utilization efficiency is high.
In addition, as another feature of the present embodiment, the light collecting performance is the same as that of the configurations of the first to third embodiments, and the necessary space as an illumination system can be further reduced. Specifically, the distance from the LED element substrate 3 to the condensing point F3 of the illumination system and the maximum diameter of the elliptical reflector 5 can be reduced. For this reason, it has the feature that it can reduce in size with the same illumination system performance.

FIG. 7 is a diagram showing a third embodiment of the illumination system according to the present invention, and shows a configuration example of a projection type display device using the illumination device of the fourth embodiment. The configuration of this example is the same configuration as the illumination system shown in FIG. 2 using the illumination device of the first embodiment, and the illumination device using the hyperbolic mirror 8 of the fourth embodiment is used as the illumination device. It corresponds to.
The lighting system includes three lighting devices 10a to 10c having the same configuration as the lighting device 10 of FIG. 6, and these three lighting devices 10a to 10c are respectively red (R) LED elements as LED elements 1a to 1c, It has a single color LED element of a green (G) LED element and a blue (B) LED element. Each of the lighting devices 10a to 10c includes elliptic reflectors 5a to 5c, LED element bases 2a to 2c, LED element substrates 3a to 3c, and hyperbolic mirrors 8a to 8c. Are reflected by the hyperbolic mirrors 8a to 8c and condensed.

The RGB light emitted from each of the illuminating devices 10a to 10c is subjected to a condensing action by the first condensing lenses 11a to 11c provided corresponding to each of the illuminating devices 10a to 10c. Then, the light enters the cross dichroic prism 12 and is synthesized by the cross dichroic prism 12. The synthesized light is condensed by the second condenser lens 13 and used as illumination light for the projection display device.
For example, a rod lens is arranged after the second condenser lens 13, and the incident surface of the rod lens is made to coincide with the condensing point position after the second condenser lens 13. After that, a predetermined optical system is arranged (none of which is shown), and can be used as illumination light for illuminating a DMD (Digital Micromirror Device) of the DLP projector. Further, the condensing position of the second condensing lens 13 can be the object image position of the illumination system lens for changing the imaging magnification.

  As a lighting system used in the projection display device, a size merits can be obtained by using a cross dichroic prism system that synthesizes three color LED elements for red, green, and blue. If the cross dichroic prism 12 does not allow the light beam to be incident to a certain degree of telecentricity, the light use efficiency deteriorates due to the film characteristics. Therefore, by using the configuration using the first condenser lenses 11a to 11c, an illumination system that is advantageous in terms of space can be obtained.

  Further, if the focal lengths of the first condenser lenses 11a to 11c and the second condenser lens 13 are changed, the condensing size and the maximum ray angle of the transmitted light of the second condenser lens 13 can be freely changed. be able to. Here, when the number of lenses is minimized, lens aberration is particularly important. Therefore, an optimum aspherical shape should be designed so as to minimize lens aberration.

  A method of combining a plurality of monochromatic lights includes a sequential mirror method, which is inferior in terms of space saving compared to the cross dichroic prism method, but the sequential mirror method is advantageous in terms of cost. Therefore, the emitted light from the illumination device may be sequentially combined by the mirror method and used as illumination light for the projection display device.

  In the configuration of FIG. 7, an illumination system that realizes telecentric illumination can be configured by removing the second condenser lens 13. Further, a fly-eye lens 14 (see FIG. 3) can be provided at the position of the second condenser lens 13 on the optical path after the cross dichroic prism 12. This corresponds to the illumination device in the configuration of FIG. 3 replaced with the illumination device having the hyperbolic mirror shown in FIG. The light made uniform using the fly-eye lens 14 can be used as illumination light for a liquid crystal panel of a liquid crystal projector.

FIG. 8 is a diagram showing a fifth embodiment of the illumination device according to the present invention, and FIG. 8A is a diagram partially showing an elliptic reflector and a hyperbolic mirror of the illumination device of this embodiment, and FIG. ) Is an overall configuration diagram of a lighting device having the configuration of FIG.
The fifth embodiment has an improved configuration so that a component having a small angle α emitted from the LED element 1 can also reach the condensing position. Specifically, a configuration is realized in which light flux (about 98.5%) having a light beam angle α in a range of about 10 to 90 degrees out of the light flux scattered and emitted from the LED element 1 can be condensed at a condensing point position. Is.

FIG. 8A illustrates the shape design of the elliptical shape of the elliptical reflector and the hyperbolic shape of the hyperbolic mirror.
The shape of the reflecting surface of the elliptical reflector 5 is constituted by a rotating body obtained by rotating a part of the ellipse around the illumination system optical axis z. In this case, the reflecting surface of the elliptical reflector 5 is a part of the elliptical shape defined by one of the regions on both sides of the illumination system optical axis z on the surface including the illumination system optical axis z. It is formed as a rotating body rotated about the optical axis z.

FIG. 8A shows a part of the above ellipse shape. Here, the shape of a part of the ellipse on one side (upper side in FIG. 8A) sandwiching the illumination system optical axis z is first shown. Stipulate.
Here, an elliptical shape 51 constituting a part of the ellipse is defined, and at this time, the first focal point F1 of the elliptical shape 51 is aligned with the center position of the LED element 1. In the case of this embodiment, the major axis p of the ellipse 51 is further inclined with respect to the illumination system optical axis z. The major axis p of the ellipse indicates a straight line connecting the first focus F1 and the second focus F2 of the ellipse. The direction of inclination of the long axis p is a direction in which the second focal point F2 of the ellipse is shifted to the elliptical shape 51 side with respect to the illumination optical axis z. That is, the position of the second focal point F2 of the elliptical shape 51 is not set on the illumination system optical axis z, but is shifted from the illumination system optical axis z. Thereby, the reflected light when the elliptical shape 51 is used as a reflecting surface is condensed toward a position slightly deviated from the illumination system optical axis z.

  Then, the shape of the reflecting surface of the elliptical reflector 5 is defined by rotating the elliptical shape 51 defined in FIG. 8A about the illumination system optical axis z. Since the position of the second focal point F2 of the elliptical shape 51 is deviated from the illumination system optical axis z, the condensed light of the second focal point in the elliptical reflector 5 obtained by rotating the second focal point F3 is expressed in three dimensions. The shape is a circle centered on the axis z. The second focal point F2 in FIG. 8B shows this state.

  Next, the specification of the hyperbolic mirror 8 will be described. The shape of the reflection surface of the hyperbolic mirror 8 is also constituted by a rotating body that rotates a part of the hyperbola around the illumination system optical axis z. In this case, the reflecting surface of the hyperbolic mirror 8 is a part of the hyperbolic shape defined by one of the regions on both sides of the illumination system optical axis z on the surface including the illumination system optical axis z. It is formed as a rotating body rotated about the optical axis z.

FIG. 8A shows a part of the hyperbolic shape described above. Here, a shape 81 of a part of a hyperbola on one side (upper side in FIG. 8A) across the illumination system optical axis z is first defined. Then, the hyperbola focal point V1 of the hyperbolic shape 81 is made to coincide with the position of the second focal point F2 of the elliptical reflector 5.
Further, the central axis q of the hyperbola is inclined, and the inclination angle of the central axis q and the specification of the hyperbola are determined so that the other focal point (second focal point) V2 of the hyperbola is positioned on the illumination system optical axis z. Thereby, it can design so that the condensing point F3 of the hyperbola mirror 8 obtained by rotating the hyperbola shape 81 may be located on the illumination system optical axis z. With the above configuration, the light reflected by the elliptical reflector 5 whose major axis of the ellipse is inclined can be reflected entirely by the hyperbolic mirror 8 whose central axis of the hyperbola is inclined and can be condensed on the illumination system optical axis z. .

  FIG. 9 is a diagram for explaining the nature of the hyperbola applied to the hyperbolic mirror. As shown in FIG. 9A, the hyperbola refers to two congruent curves h1 and h2. A straight line connecting the vertices of the two hyperbola h1 and h2 is called a hyperbola central axis q. The curves h1 and h2 approach the asymptotic lines r1 and r2 as much as possible from the hyperbolic center axis q. The two curves h1 and h2 have focal points V1 and V2, respectively, and these focal points V1 and V2 exist on the hyperbolic center axis q. Curves h1 and h2 are drawn by points where the difference in distance from the two focal points V1 and V2 is constant, and are composed of two point-symmetric curves extending infinitely.

  As shown in FIG. 9A, when a reflecting surface having a hyperbola shape is assumed, the light emitted from the focal point V1 (V2) of one of the curves h1 (h2) of the hyperbola is as if the other curve. Reflected in the direction of light emission from the focal point V2 (V1) of h2 (h1).

As shown in FIG. 9B, when the progress of the light in FIG. 9A is considered in reverse, the light beam traveling toward the focal point V1 (V2) of one of the hyperbolic curves h1 (h2) is The light is condensed at the focal point V2 (V1) of the other curve h2 (h1).
Utilizing this property, in the fourth and fifth embodiments of the present invention, the hyperbolic focal point V1 constituting the reflecting surface of the total reflection film of the hyperbolic mirror 8 is used as the elliptical focal point V1 of the elliptical reflector 5. Match with bifocal point F2. Further, the specification of the hyperbola is determined so that the total luminous flux reflected from the elliptical reflector 5 is condensed on the illumination system optical axis z without loss of light quantity. The light beam reflected by the hyperbolic mirror 8 designed in this way passes through the rear opening o2 and the front opening o1 of the elliptical reflector 5, and is condensed on the illumination system optical axis z. The condensing position at this time corresponds to the position of the second focal point on the other curved side, not the first focal point on the curved side constituting the reflecting surface of the hyperbolic mirror 8 out of the two curved lines constituting the hyperbola. To do.
With such a configuration, it is possible to construct an illumination system in which the elliptical shape of the elliptical reflector 5 and the hyperbolic shape of the hyperbolic mirror 8 are optimized so that the light quantity loss is minimized.

  The illumination device having the configuration of the present embodiment can be applied to the projection display device shown in FIG. Moreover, the illumination system which implement | achieves telecentric illumination can be comprised by removing the 2nd condensing lens 13 of the structure of FIG. 7 to which the illuminating device of this embodiment is applied. In addition, a fly-eye lens 14 can be provided at the position of the second condenser lens 13 on the optical path after the cross dichroic prism 12. The light made uniform using the fly-eye lens 14 can be used as illumination light for a liquid crystal panel of a liquid crystal projector.

DESCRIPTION OF SYMBOLS 1 ... LED element, 1a-1c ... LED element, 2 ... LED element base, 2a-2c ... LED element base, 3 ... LED element board, 3a-3c ... LED element board, 4 ... Plane mirror, 4a-4c ... Plane Mirror, 5 ... Elliptic reflector, 5a-5c ... Elliptic reflector, 6 ... Condensing lens, 7 ... Rod lens, 8 ... Hyperbolic mirror, 8a-8c ... Hyperbolic mirror, 10 ... Illuminating device, 10a-10c ... Illuminating device, 11a -11c ... Condensing lens, 12 ... Cross dichroic prism, 13 ... Condensing lens, 14 ... Fly eye lens, 100 ... High pressure discharge lamp, 101 ... Light emitting part, 110 ... LED element, 111 ... LED element substrate, 120 ... High pressure Discharge lamp, 121... Light emitting part, 122... Lamp electrode, 123 .. Ellipse reflector, 124.

Claims (11)

An LED element, an elliptical reflector made of an elliptic rotating body that reflects light emitted from the LED element, and a mirror member that reflects the light reflected by the elliptical reflector again, and collects the light reflected by the mirror member. A lighting device that focuses light toward a light spot,
When an axis passing through the center of the LED element and the condensing point is an illumination system optical axis,
The elliptical reflector includes a reflective surface having a shape obtained by rotating at least a part of an ellipse about the illumination system optical axis, and has a circular opening with a predetermined diameter centered on the illumination system optical axis. , The reflective surface is disposed toward the rear side of the illumination system optical axis direction,
The mirror member is disposed on the rear side of the illumination element optical axis direction of the LED element,
Of the light emitted from the LED element, the light reflected by the elliptical reflector is reflected by the mirror member, passes through the opening, and is condensed toward the condensing point. . The lighting device according to claim 1.
The mirror member is a plane mirror having a reflecting surface having a planar shape,
The LED element is disposed at a first focal position of the ellipse of the elliptic reflector,
The elliptical reflector is formed in a shape for condensing the light emitted from the LED element at the second focal position of the ellipse,
The reflecting surface of the mirror member is provided perpendicular to the illumination system optical axis,
The condensing point is a position corresponding to a plane-symmetric position of the second focal position when the reflecting surface of the mirror member is a symmetric plane. The lighting device according to claim 1 or 2,
An illuminating device comprising a condensing lens that acts on at least a part of light emitted from the LED element toward the inside of the opening among the light emitted from the LED element, and collects the condensed light at the condensing point. In the illuminating device of any one of Claims 1-3,
Of the light emitted from the LED element, a rod lens acting on at least a part of the light from the LED element toward the inside of the opening, the rod lens being reflected by the plane mirror and the condensing point It is arrange | positioned in the position into which the light which goes to the direction injects. The lighting device according to claim 1.
The mirror member is a hyperbolic mirror having a reflecting surface formed by rotating a hyperbola formed on a surface including the illumination system optical axis around the illumination system optical axis,
The LED element is disposed at a first focal position of the ellipse of the elliptic reflector,
The elliptical reflector is formed in a shape for condensing the light emitted from the LED element at the second focal position of the ellipse,
In the positional relationship between the two curves and the two focal points of the hyperbola that forms the reflecting surface of the mirror member, the condensing point is not the first focal point close to the curve that forms the reflecting surface of the mirror member, but the other An illumination device characterized by being coincident with a second focal point close to a curve. The lighting device according to claim 5.
The reflection surface of the elliptical reflector is a part of an elliptical shape defined by one of the regions on both sides of the illumination system optical axis on the surface including the illumination system optical axis, and the illumination system optical axis is Formed as a rotating body rotated as a center,
The position of the 2nd focus of the ellipse which forms a part of said elliptical shape has shifted | deviated from the said illumination system optical axis, The illuminating device characterized by the above-mentioned. The lighting device according to claim 6.
A reflection surface of the hyperbolic mirror is a part of a hyperbolic shape defined by one of the regions on both sides of the illumination system optical axis on the surface including the illumination system optical axis, and the illumination system optical axis is Formed as a rotating body rotated as a center,
The first focal point of the hyperbola that forms part of the hyperbola shape coincides with the second focal point of the ellipse that forms part of the elliptical shape, and the second focal point of the hyperbola is on the illumination system optical axis. A lighting device characterized by being positioned. In the illuminating device of any one of Claims 1-7,
The LED element substrate on which the LED element is mounted is located behind the mirror member in the illumination system optical axis direction, and the LED element is installed on an LED element base provided on the LED element substrate,
The said mirror member is installed in the position which condenses the light reflected by the said elliptical reflector to the said condensing point through the said opening.   A plurality of illumination devices according to any one of claims 1 to 8, a plurality of first condenser lenses for condensing each of light emitted from the plurality of illumination devices, and the plurality of first condenser lenses An illumination system comprising: a cross dichroic prism that combines light emitted from one condenser lens. The lighting system according to claim 9.
An illumination system comprising a second condenser lens on an outgoing light path of light synthesized by the cross dichroic prism. The lighting system according to claim 9.
An illumination system comprising a fly-eye lens on an outgoing light path of light synthesized by the cross dichroic prism.

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