JP2008070769A - Light source unit, illumination device and projector device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source unit capable of restraining the spread of a light beam emitted from a tapered rod to be much smaller, and an illumination device and a projector device. <P>SOLUTION: The light source device is equipped with an LED 2 which irradiates a body to be irradiated 6 with the light beam, and the tapered rod 1 that is a tapered light guiding part arranged like the optical path of the light beam from the LED 2 to the body to be irradiated 6. The tapered rod 1 is constituted so that an end face on a side where the light beam from the LED 2 is emitted is made larger than an end face on a side where the light beam is made incident, and the end face on the emitting side is formed of a projecting shape surface such as a rounded surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light source unit, an illumination device, and a projector device having a high light collecting function.

  In recent years, the brightness of semiconductor lasers (LEDs) has been improved, attracting attention as various illumination light sources, and has been studied as a light source for projectors. Advantages of using an LED as a light source for a projector include extending the life of the lamp and facilitating color balance.

  However, when an LED is considered as a light source of a projector, it is necessary to solve the following problems at present. The first problem is that the amount of light emitted from each LED is low due to insufficient light quantity, and it is necessary to adopt an optical system with high coupling efficiency, an array system in which a large number of LEDs are arranged, and the like.

  The second problem relates to collimating properties (parallelism of luminous flux). Since an LED cannot obtain a parallel luminous flux by surface emission, an optical path configuration with little light loss in the optical path and high light utilization efficiency is required. The third problem relates to illuminance uniformity, since the light quantity distribution is not uniform (flat), an integrator for uniform illumination is required.

  As means for solving these problems, a method is considered in which rod integrators (hereinafter referred to as taper rods) having a taper are arranged in an array and combined with a fly-eye lens.

  The taper rod has an inclination such that the cross-sectional size gradually increases from the incident surface toward the output surface. For this reason, since the reflected light gradually approaches parallel to the optical axis while being repeatedly reflected in the taper rod, the spread of the beam after emission can be suppressed much smaller than that of a normal rectangular parallelepiped rod integrator.

Further, as a conventional technique, Patent Document 1 discloses an invention that provides a method of generating illumination light that can be easily controlled with a spectral characteristic or color characteristic and can be established with a reliable technique. 3 illustrates an example in which an LED array and a tapered rod are combined.
JP 2005-049851 A

  However, even if a taper rod is used, the beam exiting the rod has a considerable spread. For this reason, if the fly-eye lens is made the same size as the exit surface of the taper rod, the loss of light quantity increases. If the size of the fly eye is increased to eliminate the loss of light quantity, the number of arrays that can be arrayed decreases. In order to suppress the loss of light quantity in the fly eye while keeping the number of arrays to some extent, it is necessary to further suppress the spread of the light beam emitted from the exit surface of the taper rod.

  In view of such a problem, an object of the present invention is to provide a light source unit, an illuminating device, and a projector device that further suppresses the spread of a light beam after being emitted from a tapered rod.

  In order to achieve the above object, the invention according to claim 1 is a light source that irradiates a light beam to an irradiated object, and a light guide that is arranged in the optical path of the light beam from the light source to the irradiated object and has a tapered shape. The light guide unit has a first end surface on the side where the light beam from the light source is emitted larger than the second end surface on the side on which the light beam is incident, and the first end surface is The light source unit has a convex shape surface.

  According to a second aspect of the present invention, in the light source unit of the first aspect, the convex-shaped surface is at least one of an R surface, a trapezoidal surface, and a plurality of planes formed along the R surface. It has any shape.

  According to a third aspect of the present invention, in the light source unit of the first or second aspect, the light guide unit includes a hollow rod surrounded by a mirror having an inclination, and the hollow rod is formed from the light source. The first end on the side from which the light beam is emitted is larger than the second end on the side on which the light beam is incident, and the convex shaped member is disposed at the first end. Features.

  According to a fourth aspect of the present invention, in the light source unit according to the third aspect, the convex shaped member includes a convex lens, a trapezoidal prism, and a plurality of planes formed along the lens shape of the convex lens. It has the shape of at least any one of these, It is characterized by the above-mentioned.

  According to a fifth aspect of the present invention, in the light source unit according to any one of the first to fourth aspects, the light source is disposed in the vicinity of the second end face and in the vicinity of the second end portion.

  The invention according to claim 6 is the light source unit according to any one of claims 1 to 4, wherein the convex shaped surface and the convex shaped member are configured to emit light emitted from the outermost portion of the light beam emitting end, It is characterized by being shaped parallel to the optical axis or condensing with respect to the optical axis.

  According to a seventh aspect of the present invention, there is provided a light source unit according to any one of the first to sixth aspects, a lens array in which a plurality of microscopic lenses having light transmissivity are arranged, and a light collecting unit. When the light beam irradiated from the light source to the irradiated object is transmitted, the emission end shapes of the light beams in the light source unit, the lens array, and the condensing optical system are superimposed on the irradiated object. It is a lighting device that illuminates.

  According to an eighth aspect of the present invention, in the illumination device according to the seventh aspect, the light emitting unit has an emission end shape that is similar to the shape of the irradiated object.

  A ninth aspect of the invention includes the illumination device according to the seventh or eighth aspect, a light modulation element that is arranged in an array and modulates a light beam, and a projection optical system, and the surface to be irradiated is irradiated from a light source. When the light beam is transmitted, the light beam emitting end shape of the illumination device is illuminated on the light modulation element, and the illuminated light modulation element is projected onto the irradiated surface by the projection optical system. It is characterized by that.

  According to a tenth aspect of the present invention, in the projector device according to the ninth aspect, the shape of the light beam exit end in the illumination device is formed to be similar to the shape of the light modulation element.

  According to an eleventh aspect of the present invention, in the projector device according to the ninth or tenth aspect, a polarization conversion element is provided in an optical path between the light source unit and the lens array provided in the illumination device.

  According to a twelfth aspect of the present invention, in the projector device according to any one of the ninth to eleventh aspects, the illumination device includes illumination lights of red light, green light, and blue light as light emission sources, respectively, and illumination light. It is provided for each.

  According to a thirteenth aspect of the present invention, in the projector device according to any one of the ninth to eleventh aspects, the illumination device includes white illumination light as a light source, and the projector device is illuminated from the illumination device. It has a spectroscopic means for splitting illumination light into red light, green light, and blue light.

  According to a fourteenth aspect of the present invention, in the projector device according to any one of the ninth to eleventh aspects, the illumination device includes illumination light of red light, green light, blue light, and white light as a light source. In addition, the projector device is arranged in an array so that the color balance of each color in the light emitting source is equalized, and the projector device has a spectroscopic unit that splits the illumination light illuminated from the illumination device into red light, green light, and blue light. It is characterized by that.

  As described above, according to the light source unit, the illumination device, and the projector device of the present invention, it is possible to further suppress the spread of the light beam after being emitted from the taper rod.

  In this embodiment, it is possible to further suppress the spread of the beam by making the exit end face of the tapered rod convex. Examples of the convex shape include an R surface, a trapezoidal shape, and a shape along a minute plane along the R surface.

  Further, the taper rod is made of a transparent glass material or plastic material, and a hollow taper rod combined with a mirror is also conceivable. In this case, although the exit end face does not exist, an equivalent effect can be obtained by arranging another member having a light collecting function on the exit end face.

  Hereinafter, the light source unit, the illumination device, and the projector device of the present embodiment will be described with reference to the drawings. In addition, this embodiment is not limited to what is described below, A various change is possible in the range which does not deviate from the meaning.

FIG. 1 is a diagram schematically illustrating a light guide unit of a conventional light source unit and a light guide unit of the light source unit of the present embodiment.
In FIG. 1, the basic unit in the light guide part of the light source unit of this embodiment is shown in comparison with a conventional rod integrator and a tapered rod.
FIG. 1A shows a case where an LED chip light source is arranged in the vicinity of an incident end face of a rectangular parallelepiped rod generally used as a rod integrator. In this case, since the light beam emitted from the emission end face exits at the same angle as that at the time of incidence, the spread of the beam becomes large.

FIG. 1B shows a conventional tapered rod.
Each time the light beam is reflected by the tapered portion of the taper rod, the light beam approaches parallel to the optical axis, so that the spread of the light beam emitted from the exit end face is much smaller than that of the rectangular parallelepiped rod. However, there is a limit to suppressing the spread of the light beam, and the width of the light beam emitted from the rod end face cannot be reduced to the same size as the rod end face size.

  FIG.1 (c) is a figure which shows the taper rod with a convex surface which concerns on this embodiment. Here, an R-shaped surface is used as an example of the convex shape. By transmitting the light beam, which is made parallel to the optical axis by the taper rod, further through the convex surface (R surface), it becomes possible to bring the light beam (light beam) on the outer periphery to the center, and the light beam more parallel to the optical axis. Can be obtained.

  FIG. 2 is a view showing a light source unit of a tapered rod type with end face R of the present embodiment.

  Let's look at the coupling efficiency at the rod entrance end. A light beam emitted from a solid-state light source such as an LED is refracted at the incident end of the taper rod 1 and enters the rod. Accordingly, if the light emitting surface and the rod incident end are brought into close contact with each other, the coupling efficiency can be made 100%. Actually, even if a slight gap is provided due to heat generation or the like, it is possible to provide a considerably high coupling efficiency.

  Next, the propagation of the light beam in the taper rod 1 will be considered. For example, when the glass material is BK7 (refractive index: about 1.52), the critical angle is about 41.14 °, and therefore the angle formed by the light beam entering the tapered rod 1 from the incident end and the optical axis is 41.14. ° or less. Therefore, since these light beams are totally reflected by the side surface (tapered surface) of the taper rod 1, there is almost no loss of light quantity related to the propagation of the beam in the rod.

  If the angle of the taper surface is α, the angle of the light beam approaches the optical axis by 2α every time it is reflected once. If the taper rod 1 is infinitely long, all the light beams will reach the exit end below the rod angle.

  However, there is a limitation on the size of the emission end, and there is a limit in itself even if it is made longer. If the size of the entrance end and the exit end is fixed, the shorter the rod, the greater the taper angle, and the smaller the angle of the beam with a single reflection, the less the number of reflections. On the other hand, if the rod is lengthened, the number of reflections increases, but the beam angle decrease in one reflection becomes small. In any case, there is a beam having an angle larger than the angle of the rod at the exit end. Of these, the one with the maximum angle will be referred to as the maximum angle beam in the rod.

  Next, let us look at the behavior of the light beam on the exit surface. If the exit surface is a plane perpendicular to the optical axis, a light beam having an angle with respect to the optical axis is refracted at the exit surface and diverges as a light beam having a larger angle. In order to suppress this as much as possible, R is attached to the emission end face. In FIG. 2, this R is formed such that the maximum angle beam in the rod at the upper and lower ends of the exit end face is parallel to the optical axis after exiting the rod. Therefore, at this time, the light beam parallel region after emission can be made the longest. The length of the parallel region is effective for the light efficiency of the projector illumination system, which will be described later.

  In the present embodiment, the end shape of the taper rod 1 is not limited to the R surface, and as shown in FIGS. 3 and 4, for example, by arranging a large number of planes along the trapezoidal surface or the R surface, the same shape can be obtained. An effect can be obtained. A similar effect can be obtained by using a hollow taper rod in which four mirrors having an inclination with respect to the optical axis are combined in a quadrangular pyramid instead of the transparent taper rod 1. However, in the case of a hollow rod, since there is no exit end face, a convex surface such as an R-face or a trapezoidal face is formed by another member at the exit portion.

  Which of the above-mentioned shapes is used for the convex shape of the end face, and whether it is made of a transparent body or a reflector, depends on the lighting specifications, manufacturability and assembly cost required for the product. Selected. Various combinations are possible in this embodiment.

  Next, the case where the light source units described above are arrayed and used as an illumination device will be described. In the following description, the taper rod with the end face R is used for explanation. However, the same effect can be obtained when other end face shapes and hollow rods are used, and therefore the explanation is omitted here.

FIG. 5 is a diagram illustrating an example of a lighting device according to the present embodiment.
As shown to Fig.5 (a), the illuminating device of this embodiment has the light source unit 3, the fly-eye lens 4, the condenser lens 5, and the to-be-irradiated body 6 which arrayed the taper rod 1 and LED2 as a group. I have.

  At the exit end of each taper rod 1, a uniform illuminance distribution is obtained by the integration action of the rod. The light beam emitted from the exit end of the taper rod 1 forms a beam parallel region by the action of the R surface provided at the exit end. By disposing the fly-eye lens 4 in this region, the light beam emitted from the taper rod 1 enters the fly-eye lens 4 without loss.

  The fly-eye lens 4 is a lens array in which microscopic single lenses having optical transparency are arranged vertically and horizontally. The fly-eye lens 4 and the condenser lens 5 project the shape of the exit end of the taper rod 1 on the irradiated body 6 in an overlapping manner. Therefore, the irradiated body 6 is illuminated in a form in which the illuminance at the end of each tapered rod 1 is combined. As described above, since the emission end of each tapered rod 1 has a uniform illuminance distribution, the irradiated surface obtained by combining these also has a uniform illuminance distribution.

  That is, by combining the LED array of the LED 2, the tapered rod array of the tapered rod 1 with the end face R, the fly-eye lens 4, and the condenser lens 5, an illumination device having a uniform illuminance distribution with little light loss can be obtained. . Although only one direction is shown in FIG. 5, considering both vertical and horizontal directions of the irradiated object 6, an efficient illumination system is configured by making the rod emitting end shape similar to the irradiated object 6.

  The LED 2 used in the illumination device of the present embodiment may be a white LED or a single color LED, but R (Red), G (Green), and B (Blue) which are the three primary colors of light as shown in FIG. May be combined on the matrix. Further, since each rod is projected onto the irradiated body with almost no difference in the amount of light, it may be combined in a mottled manner as shown on the left side of FIG. 5B, but is collected for each color as shown on the right side of FIG. You can also.

  Next, a projector device using the illumination device of this embodiment as an illumination optical system will be described. FIG. 6 is a diagram schematically showing an illumination optical system (illumination device) of the projector device according to the present embodiment. Basically, the configuration of the illumination optical system is the same as that shown in FIG.

  The first consideration is the incident angle of the light beam to a light valve (referred to as an image forming element or a light modulation element) 61 that is an object to be irradiated of the projector apparatus according to the present embodiment. In the projector device of the present embodiment, the light beam irradiated on the light valve 61 is projected onto the screen by the projection lens. When the illumination light of the light valve 61 has a large angle with respect to the optical axis, the projection lens is displaced, so it is desirable that the irradiation beam is a beam close to the optical axis. The extent to which the irradiation light from the projection lens can be tolerated is determined by the design of the projector device such as the brightness of the projection lens. As will be described later, it goes without saying that in the present invention, the light valve can be implemented by either a reflection type or a transmission type.

  In order to bring the irradiation beam close to the optical axis, it is necessary to increase the distance between the condenser lens and the light valve 61. Incidentally, in order to increase the distance between the condenser lens and the light valve 61, it is necessary to increase the distance between the rod end of the taper rod 1 and the fly-eye lens 4.

  What is effective here is the existence of a parallel region of the light beam after the emission from the rod. In the case of a conventional taper rod in which the exit end of the taper rod 1 is a flat surface or an insufficient end even if the exit end surface has an R, the light beam emitted from the taper rod 1 spreads immediately after the exit. On the other hand, in order to pick up a light beam without loss of light quantity or with reduced light quantity loss, for example, the diameter of the fly-eye lens 4 must be increased as shown in FIG. If the diameter of the fly-eye lens 4 is increased, the number of arrays is reduced, so that the amount of light cannot be earned. Therefore, by providing the beam parallel region, it is possible to capture the emitted beam from the taper rod 1 into the fly-eye lens 4 without loss while securing the number of arrays.

  In FIG. 6, the condenser lens has a two-lens configuration including a first condenser lens 51 and a second condenser lens 52. The second condenser lens 52 is for reducing the irradiation angle of the light beam that irradiates the light valve 61, and is not necessarily essential. However, in order to reduce the displacement of the projection lens, it is more preferable to use a two-lens configuration.

  A second consideration is how to arrange the polarization conversion elements. In a projector device using a general high-pressure lamp (+ parabolic reflector), two sets (one pair) of fly-eye lenses are used, and the polarization conversion element is located immediately after the second fly-eye lens (light beam irradiation surface direction). ) Is usually placed. This is because the parallel light beam from the reflector is condensed in the vicinity of the second fly-eye lens by the first fly-eye lens. A polarization conversion element is disposed in the vicinity of the condensing position to reduce the light amount loss at the polarization conversion element unit.

  However, in the case of a system using a taper rod as in this embodiment, the light beam spreads when placed after a fly-eye lens (corresponding to a second fly-eye lens in a general projector device). That is, when the polarization conversion element is disposed after the fly-eye lens as viewed from the irradiation direction, the light amount loss becomes large. Again, the light beam parallel region after the taper rod emission is effective. That is, as shown in FIG. 7, if a polarization conversion element is arranged in this light beam parallel region, the loss of the light beam by the polarization conversion element can be suppressed.

  FIG. 8 is a diagram schematically showing a transmissive light valve type projector device including three illumination systems for each of the R, G, and B configurations described above in the projector device of the present embodiment. FIG. 9 is a diagram showing a case where one illumination system is provided and separated into R, G, and B by a dichroic mirror. FIG. 10 is an external view schematically showing a reflective light valve type projector apparatus having three illumination systems of R, G, and B. As shown in FIG.

  The light beam emitted from the LED array is separated into colors of the dichroic mirrors R, G, and B in the optical path, and is incident on the cross prism 10 via the red LCD 91, the green LCD 92, and the blue LCD 93, which are light valves, respectively. It is sent to the projection lens 11 which is a projection optical system. The LED may be a white LED, or may have a matrix arrangement in which R, G, and B are arranged in an appropriate balance as illustrated in the upper part of FIG. By arranging in this way, it is possible to adopt an LED light source configuration in consideration of color balance.

  In the case of the projector device shown in FIG. 10, a PBS (deflection beam splitter) 12 and an LCOS (Liquid Crystal On Silicon: reflection type light valve) 13 are used instead of the dichroic mirror 8 and the LCDs 91 to 93 for each color. . Also by using such a configuration, a configuration of an LED light source in consideration of color balance can be taken.

  As described above, by using the tapered rod with the emission end face R, it is possible to provide a projector device of an LED light source that has high light utilization efficiency, is easily arrayed, and has uniform illuminance.

  According to the light source unit, the illuminating device, and the projector device of the present embodiment, a light source unit that suppresses the spread of a light beam after emission even with a solid light source having a large light emitting area can be obtained by using a tapered rod with an end surface that is convex. It is done. In particular, by setting the shape of the emission end so that the emitted light beams at the upper and lower ends on the emission end side are parallel to the optical axis, the parallel region of the emitted light beam can be made long.

  According to the present embodiment, by combining a tapered rod having a convex end surface, a fly-eye lens, and a condenser lens, a lighting device or a projector device with high light utilization efficiency, uniform illuminance distribution, and easy arraying can be obtained. Can be provided.

  In addition, a combination of a tapered rod with a convex end face, a fly-eye lens, and a condenser lens, and a polarization conversion element disposed immediately after the exit end of the tapered rod, makes it possible to produce a solid-state light source having a large light emitting surface such as an LED. Even if it is used, it is possible to configure an illumination system that does not lose light amount such as vignetting.

  Further, the projector apparatus according to the present embodiment includes a configuration in which the LED illumination system using the taper rod is provided with three systems of R, G, and B, or one of the R, G, and B3 systems and is provided with a dichroic mirror. , B, or an illumination system in which LEDs are arrayed, etc., an LED light source configuration that takes color balance into consideration is possible.

(A) And (b) is a figure which shows the light guide part of the conventional light source unit, (c) is a figure which shows the light guide part of the light source unit of this embodiment. It is sectional drawing which shows typically an example of the light guide part of the light source unit of this embodiment. It is sectional drawing which shows typically another example of the light guide part of the light source unit of this embodiment. It is sectional drawing which shows the example of a shape of the output side end surface of a light guide part. (A) is a figure which shows the illuminating device of this embodiment, (b) is a figure which shows typically the example of arrangement | positioning of the LED array for every R, G, B. (A) is a figure which shows the illumination optical system when the lens diameter of a fly eye lens is made small, (b) is a figure which shows the illumination optical system when the lens diameter of a fly eye lens is enlarged. It is a figure which shows the case where a polarization conversion element is provided in the illuminating device. It is a figure which shows the projector apparatus provided with the illuminating device for every color of R, G, B. It is a figure which shows an example of the projector apparatus which has an illuminating device provided with the LED array comprised by the matrix arrangement | sequence of each color of white or R, G, B. It is a perspective view which shows typically the external appearance of the projector apparatus of this embodiment.

Explanation of symbols

1 Taper rod 2 LED
DESCRIPTION OF SYMBOLS 3 Light source unit 4 Fly eye lens 5 Condenser lens 51 1st condenser lens 52 2nd condenser lens 6 Object 61 Light valve 7 Polarization conversion element 8 Dichroic mirror 91 Red LCD
92 Green LCD
93 Blue LCD
10 Cross prism 11 Projection lens 12 Deflection beam splitter 13 LCOS

Claims (14)

A light source for irradiating the irradiated object with a light beam;
A light guide unit disposed in the optical path of the light beam from the light source to the irradiated body, and having a tapered shape;
In the light guide section, the first end surface on the side where the light beam from the light source is emitted is larger than the second end surface on the side on which the light beam is incident, and the first end surface is convex. A light source unit characterized by being a mold-shaped surface.   2. The convex shape surface according to claim 1, wherein the convex shape surface has at least one of an R surface, a trapezoid surface, and a plurality of planes formed along the R surface. Light source unit. The light guide has a hollow rod surrounded by a mirror having an inclination,
The hollow rod has a first end on the side from which the light beam is emitted from the light source is larger than a second end on the side on which the light beam is incident, and the first rod The light source unit according to claim 1, wherein a convex shape member is disposed at an end portion.   The convex-shaped member has at least one of a shape of a convex lens, a trapezoidal prism, and a plurality of planes formed along the lens shape of the convex lens. 3. The light source unit according to 3.   5. The light source unit according to claim 1, wherein the light source is disposed in the vicinity of the second end surface and in the vicinity of the second end portion. 6.   The convex shape surface and the convex shape member are shaped so as to condense outgoing light at the outermost part of the outgoing end of the light beam parallel to the optical axis or condensing with respect to the optical axis. The light source unit according to claim 1, wherein the light source unit is a light source unit. The light source unit according to any one of claims 1 to 6, arranged in a matrix, a lens array in which a plurality of microscopic lenses having light transmittance are arranged, and a condensing optical system,
When transmitting the light beam emitted from the light source to the irradiated object, the respective emission end shapes of the light beams in the light source unit, the lens array, and the condensing optical system are superimposed on the irradiated object. A lighting device characterized by illuminating.   The lighting device according to claim 7, wherein the shape of the emission end of the light source unit is similar to the shape of the irradiated object. A lighting device according to claim 7 or 8, a light modulation element that is arranged in an array and modulates a light beam, and a projection optical system,
When transmitting the light beam emitted from the light source to the illuminated surface, the light beam emitting end shape of the illumination device is illuminated on the light modulation element, and the illuminated light modulation element is illuminated by the projection optics. Projecting onto the irradiated surface by a system.   The projector device according to claim 9, wherein the shape of the light emitting end of the light beam in the illumination device is formed to be similar to the shape of the light modulation element.   11. The projector device according to claim 9, further comprising a polarization conversion element in an optical path between the light source unit and the lens array provided in the illumination device.   The projector device according to claim 9, wherein the illumination device includes illumination light of red light, green light, and blue light as light emission sources, and is provided for each illumination light. . The illumination device includes white illumination light as a light source,
The projector according to any one of claims 9 to 11, wherein the projector device includes a spectroscopic unit that splits the illumination light illuminated from the illumination device into red light, green light, and blue light. apparatus. The illumination device includes illumination light of red light, green light, blue light, and white light as a light source, and is arranged in an array so that the color balance of each color in the light source is equalized,
The projector according to any one of claims 9 to 11, wherein the projector device includes a spectroscopic unit that splits the illumination light illuminated from the illumination device into red light, green light, and blue light. apparatus.

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