JPWO2014109333A1 - Wavelength conversion device, illumination optical system, and electronic apparatus using the same - Google Patents

Abstract

The illumination optical system of the present invention includes an array light source 20 that emits blue light, a reflection region 52 that reflects blue light, a first phosphor region 54 that emits red light based on blue light, and a second light that emits green light. The phosphor wheel 50 including the phosphor region 56, the dichroic mirror 30 that transmits the blue light from the array light source 20, and reflects the red light and the green light from the phosphor wheel 50, and the blue color from the phosphor wheel 50. A reflection mirror 40 for reflecting light, an optical axis C1, front group lenses L1 and L2 for condensing blue light from the array light source 20, and an optical axis C2 shifted from the optical axis C1; And rear group lenses L3 and L4 that collect blue light from the group lenses L1 and L2 on the surface of the phosphor wheel 50.

Description

  The present invention relates to an illumination optical system using a laser light source that emits laser light in a blue band, and more particularly to an illumination optical system used for a light source of an electronic device such as a projector or an optical apparatus.

  It is known that a blue laser emitter is used as a light source for a light source unit of a projector (Patent Document 1). The light source unit includes a blue laser emitter, a phosphor wheel, and a plurality of reflecting mirrors and dichroic mirrors. The phosphor wheel has a disk shape rotated by a motor, and the phosphor wheel has a transmission part that transmits blue band light, and a phosphor that emits blue band light in red band and green band. Each layer is formed.

Japanese Patent No. 4711154

  Since the light source unit shown in Patent Document 1 has a configuration in which the phosphor wheel transmits blue band light, the optical system layout and the like are limited, and the light source unit is not necessarily reduced in size and space. It was not suitable for.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a wavelength conversion device, an illumination optical system, and an electronic apparatus using the same that reduce the number of optical components to save space, reduce weight, and reduce costs.

  A wavelength conversion device according to the present invention is used in an illumination optical system, and includes a wavelength conversion region that emits light having a wavelength different from that of the blue band based on incident blue band light. Are formed concentrically at the center of rotation, and the wavelength conversion region is formed in n sets (n is an integer of 2 or more) in the radial direction. Preferably, the one wavelength conversion region includes a first phosphor region that emits red band light based on blue band light, and a second phosphor region that emits green band light based on blue band light. Including.

  The wavelength conversion device according to the present invention further includes a reflection region that reflects light in the first wavelength band, a first phosphor region that emits light in the second wavelength band based on at least light in the first wavelength band, and A first rotating member including a second phosphor region that emits light in a third wavelength band; a first transmission region that transmits light in the first wavelength band reflected from the reflection region; A second transmission region that transmits light in the second wavelength band output from the first phosphor region, and a third that transmits light in the third wavelength band output from the second phosphor region. And a second rotating member including a transmission region.

  The wavelength conversion device according to the present invention further includes a reflection region that reflects light in the first wavelength band, and a first phosphor region that emits light in the second wavelength band based on at least light in the first wavelength band. A first rotation member including a first transmission region that transmits light in the first wavelength band reflected from the reflection region, and light in the second wavelength band output from the first phosphor region. A second rotating member including a first extraction region for extracting light in the third wavelength band and a second extraction region for extracting light in the fourth wavelength band from the light in the second wavelength band; Including.

  An illumination optical system according to the present invention includes the wavelength conversion device having the above-described configuration and an optical system that causes n sets of light beams in the blue band to enter the wavelength conversion device. Preferably, the optical system includes n sets of lenses for condensing a blue-band light bundle in each of the n sets of wavelength conversion regions, and an optical axis of the blue-band light bundle is different from an optical axis of the lens. The projector and the endoscope according to the present invention are configured using the illumination optical system having the above configuration.

  According to the present invention, it is possible to provide an illumination optical system in which the number of parts is reduced, which is reduced in size, weight, and cost, and an electronic apparatus using the illumination optical system.

It is a figure explaining the principle of the illumination optical system which concerns on the 1st Example of this invention. It is a schematic sectional drawing which shows the structural example of the array light source shown in FIG. 3A is a plan view of the phosphor wheel of the present embodiment, and FIG. 3B is a cross-sectional view taken along the line XX. FIG. 4A is a diagram illustrating a state in which light in the blue band is reflected by the phosphor wheel according to the present embodiment, and FIG. 4B is a diagram illustrating the red band / green band by the phosphor wheel according to the present embodiment. It is a figure explaining a mode that light is reflected. FIG. 5A is a diagram for explaining the principle of an illumination optical system according to the second embodiment of the present invention, and FIG. 5B is a plan view of a phosphor wheel used in the second embodiment, FIG. FIG. 5C is a diagram for explaining the combined luminance of the R, G, and B lights combined according to the second embodiment. It is a graph which shows the relationship between the light emission change efficiency of a fluorescent substance, and irradiation energy density. It is a figure explaining the modification of the fluorescent substance wheel applicable to the 1st, 2nd Example of this invention. It is a figure explaining the modification of the fluorescent substance wheel applicable to the 1st, 2nd Example of this invention. It is a figure explaining the principle of the illumination optical system which concerns on the 3rd Example of this invention. It is a figure explaining the principle of the illumination optical system which concerns on the 4th Example of this invention. FIG. 10A shows a configuration of the phosphor wheel in FIG. 10, FIG. 10A is a plan view of the second wheel member, FIG. 10B is a plan view of the first wheel member, and FIG. It is a top view which shows the modification of a 2nd wheel member. It is a graph which shows the relationship between the light intensity of a green zone | band and the blue zone | band included therein, and an angle. It is a graph which shows the relationship between the light intensity and angle of the light of a green zone | band and a blue zone | band when the fluorescent substance wheel by the 4th Example of this invention is used. It is a figure which shows an example of the wavelength selected in the blue transmission area | region of a 2nd wheel member, a red transmission area | region, and a green transmission area | region. It is a figure explaining the modification of the 2nd wheel member concerning the 4th example of the present invention. It is a figure explaining the modification of the 2nd wheel member concerning the 4th example of the present invention. It is a figure explaining the modification of the 2nd wheel member concerning the 4th example of the present invention. It is a figure which shows the modification of the illumination optical system which concerns on the 4th Example of this invention. It is a figure which shows the modification of the illumination optical system which concerns on the 4th Example of this invention. It is a figure which shows the illumination optical system which concerns on the 5th Example of this invention. FIG. 21A is a plan view of a first wheel member according to the fifth embodiment, and FIG. 21B is a plan view of a second wheel member. It is a figure explaining the principle of the illumination optical system which concerns on the 6th Example of this invention. FIG. 23A is a plan view of the phosphor wheel of the sixth embodiment, and FIG. 23B is a cross-sectional view taken along the line XX of FIG. It is a figure explaining the principle of the illumination optical system which concerns on the 7th Example of this invention. It is a schematic sectional drawing of the phosphor wheel which concerns on the 7th Example of this invention. It is a figure explaining the other method of dividing | segmenting a laser beam. It is a figure explaining the modification of the illumination optical system which concerns on the 6th Example of this invention.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. In a preferred aspect of the present invention, the illumination optical system uses a blue laser element or an array light source in which blue light emitting diodes are arrayed as a semiconductor light emitting element that emits blue light having a short wavelength. In a further preferred aspect, the illumination optical system is used in a projector that reflects light by a light modulation device such as DLP or DMD. It should be noted that the scale of the drawings is emphasized for easy understanding of the features of the invention and is not necessarily the same as the scale of an actual device.

  FIG. 1 is a diagram for explaining the basic principle of an illumination optical system according to the first embodiment of the present invention. In the following description, red band light, green band light, and blue band light may be abbreviated as R, G, and B for convenience.

  The illumination optical system 10 of the present embodiment includes an array light source 20 that emits blue band laser light as excitation light, front group lenses L1 and L2 that condense the laser light from the array light source 20, and a front group lens L1. , Rear group lenses L3 and L4 for condensing the laser light collected by L2 on the phosphor wheel 50, a dichroic mirror 30 that transmits light in the blue band and reflects light in the red band and green band, Reflected by a reflection mirror 40 disposed at the rear of the dichroic mirror 30 and at the same angle as the dichroic mirror 30, a disk-shaped phosphor wheel 50, a motor 60 that rotates the phosphor wheel 50, and the dichroic mirror 30. L5 that collects the red band light and the green band light that has been reflected, and the blue band light that has been reflected by the reflecting mirror 40, and a condensing lens 5 by configured to include a light tunnel 70 that transmits the light collected. The light emitted from the light tunnel 70 is guided to a spatial modulation device such as DMD (not shown), an optical fiber, or the like. The condensing lens L5 and the light tunnel 70 are not necessarily essential, and can be replaced or changed to an optical system according to the light source of the applied electronic device.

  The array light source 20 includes a plurality of semiconductor laser elements (or blue light-emitting diodes) that emit blue-band laser light in an array. The plurality of semiconductor laser elements are arranged one-dimensionally or two-dimensionally, and the plurality of semiconductor laser elements are driven at the same time, so that laser light is emitted from each semiconductor laser element all at once.

  FIG. 2 is a schematic cross-sectional view showing one configuration example of the array light source. As shown in the figure, a substrate on which a plurality of semiconductor laser elements are mounted is supported by a support member 22 made of a metal material having high thermal conductivity, such as aluminum. A lens 24 for collimating the laser light emitted from each semiconductor laser element is attached to the surface of the support member 22. Further, a reflection mirror 26 is disposed on the side facing the support member 22, and the reflection mirror 26 reflects blue band light emitted from each semiconductor laser element in a certain direction to generate a laser beam bundle Lb.

  The front group lens L1 is composed of, for example, a plano-convex lens and condenses the laser beam Lb from the array light source 20, and the front group lens L2 is composed of, for example, a concave lens, and the front group lenses L1 and L2 from the array light source 20 The laser beam Lb is condensed into parallel light. The optical axis C1 of the front group lenses L1 and L2 is the center of the lenses L1 and L2. The front group lenses L1 and L2 may be any optical system that can collect the laser beam bundle Lb from the array light source 20, and the number of lenses constituting the front group lens may be one. Or three or more. Further, the lens may be either a spherical lens or an aspheric lens.

  The rear group lenses L3 and L4 are composed of, for example, a combination of a spherical lens such as a convex lens and a concave lens, or an aspheric lens, and the laser beam bundle Lb collected by the front group lenses L1 and L2 is further collected on the phosphor wheel 50. Shine. The optical axis C2 of the rear group lenses L3 and L4 is the center of the lenses L3 and L4. The rear group lenses L3 and L4 may be any optical system that can focus the laser beam bundle Lb on the phosphor wheel 50, and the number of lenses constituting the rear group lens may be one. Or three or more. It should be noted that the illumination optical system 10 of this embodiment is an optical system in which the optical axis C2 of the rear group lenses L3 and L4 is shifted from the optical axis C1 of the front group lenses L1 and L2. The shifts of the optical axes C1 and C2 are adjusted so that the laser beams condensed by the group lenses L1 and L2 are incident on one half of the rear group lens L3.

  The dichroic mirror 30 is disposed on the optical axes C1 and C2, and intersects the optical axes C1 and C2 at an angle of approximately 45 degrees. The dichroic mirror 30 has an optical property of transmitting blue band light and reflecting red band and green band light. For this reason, the light in the blue band collected by the front lens groups L1 and L2 passes through the dichroic mirror 30 and enters one half of the rear lens groups L3 and L4. Further, the dichroic mirror 30 reflects light in the red band and the green band reflected by the phosphor wheel 50 almost at right angles to the optical axis, as will be described later.

  The reflection mirror 40 disposed at the same angle as the dichroic mirror 30 is located at the rear part of the dichroic mirror 30 and reflects the blue band light normally reflected by the phosphor wheel 50 in a direction orthogonal to the optical axes C1 and C2. To do. The reflection mirror 40 can be configured by a total reflection mirror that reflects all wavelengths, or a dichroic mirror that reflects light in the blue band and transmits light in the red and green bands. When the reflection mirror 40 is composed of the latter dichroic mirror, the reflection mirror 40 may be disposed behind or in front of the dichroic mirror 30. More preferably, the reflection mirror 40 is positioned so as not to block the laser light Lb collected by the front lens groups L1 and L2, and coincides with the optical axis of the condenser lens L5. However, the positional relationship may be such that the laser beam Lb overlaps the reflection mirror 40.

  The condensing lens L5 condenses the light reflected by the dichroic mirror 30 and the reflecting mirror 40 and makes the collected light enter the light tunnel 70. The optical axis C3 of the lens L5 is the center of the lens L5, and the optical axis C3 is the same as the optical axes of the reflection mirror 40 and the dichroic mirror 30, and is orthogonal to the optical axes C1 and C2. Therefore, the light reflected by the dichroic mirror 30 and the reflection mirror 40 is condensed on the same optical path by the condenser lens L5.

  As described above, the rear lens groups L3 and L4 are arranged between the dichroic mirror 30 and the phosphor wheel 50, and condense the light in the blue band transmitted through the dichroic mirror 30 on the surface of the phosphor wheel 50. As shown in FIG. 3, the phosphor wheel 50 is a disk-like rotating body that is rotated at a constant speed by a motor 60, and the surface thereof reflects the light in the blue band in the circumferential direction. The region 52 includes a first phosphor region 54 that emits light in the red band when excited by light in the blue band, and a second phosphor region 56 that emits light in the green band when excited by light in the blue band. It is out. The reflection region 52, the first phosphor region 54, and the second phosphor region 56 have a certain width in the radial direction, and this width is the width of the spot P collected by the rear group lenses L3 and L4. Somewhat larger than the diameter. In addition, the circumferential lengths of the reflection region 52, the first phosphor region 54, and the second phosphor region 56, that is, the respective inner angles thereof, depend on the required R, G, B luminances, etc. It is selected appropriately.

  In a preferred embodiment, the phosphor wheel 50 includes a base material made of glass, resin, or metal. In a preferred example, the surface of the rotator constitutes a reflecting mirror that reflects light of R, G, and B wavelengths, and the first phosphor region 54 and the second phosphor region 56 are the surfaces of the reflecting mirror. The phosphor layers 54a and 54b are laminated. Further, a reflective layer that reflects at least blue band light may be formed on the surface of the substrate. Further, the reflection region 52 may be formed with irregularities on its surface so as to diffuse the incident blue band light minutely.

  As described above, the first phosphor region 54 includes the phosphor layer 54a that is excited by the blue band laser light and emits the red band light on the surface of the base material. The phosphor layer 54a may be formed on the surface of the base material, or may be formed on the reflective layer by forming a reflective layer on the surface of the base material. It should be noted that the thickness of the phosphor layer 54a shown in FIG. 3B is exaggerated. Similarly, the second phosphor region 56 includes a phosphor layer 56a that is excited by blue band light and emits green band light. The phosphor materials constituting the phosphor layers 54a and 56a include YAG (yttrium, aluminum, garnet), TAG (terbium, aluminum, garnet), sialon, BOS (barium orthosilicate), and nitride compounds. It has been known. The phosphor layers 54a and 56a are, for example, applied on the surface of the base material mixed with a phosphor material and a resin material or a ceramic material, or pasted on the surface of the base material and a sheet-like material mixed with the phosphor material. You may make it attach. Thus, the surface of the phosphor wheel 50 is irradiated with the light in the blue band of the spot P, and the phosphor wheel 50 is rotated so that the reflection region 52 and the first and second phosphor regions 54 and 56 are formed. The spot P is optically scanned.

  In the above example, the phosphor wheel 50 is formed with the phosphor layers 54a and 56a for emitting light in the red band and the green band. However, the light excited by the blue laser light is not necessarily red. It is not limited to light in the band and the green band. For example, a phosphor layer that excites light in the yellow, magenta, and cyan bands may be formed.

  Next, an operation of sequentially generating R, G, and B light will be described with reference to FIG. FIG. 4A shows a state in which blue band light is regularly reflected by the reflection region 52 of the phosphor wheel 50. That is, the parallel light bundles Lb from the front lens groups L1 and L2 are transmitted through the dichroic mirror 30 and incident on one half of the rear lens groups L3 and L4 shifted from the optical axis C2. The light beam Lb irradiates the reflection region 52 of the phosphor wheel 50 by the rear lens groups L3 and L4. At this time, the light beam Lb is regularly reflected, that is, the incident angle and the reflection angle of the light beam Lb with respect to the optical axis C2 are substantially equal. Accordingly, the light beam Lb reflected by the phosphor wheel 50 is emitted from the opposite side of the rear lens groups L3 and L4, and the light Lb passes through the dichroic mirror 30 and is reflected by the reflecting mirror 40 at a substantially right angle. And condensed by the condenser lens L5.

  FIG. 4B shows a state in which red band or green band light is reflected by the first or second phosphor regions 54 and 56 of the phosphor wheel 50. That is, as in the case of FIG. 4A, the light flux Lb in the blue band irradiates the first phosphor region 54. The phosphor layer 54a excited by the light beam Lb emits light in the red band. At this time, the light in the red band becomes light spreading in a Lambertian shape (uniform diffusion). The red band light Lr reflected in a Lambertian shape is condensed by the lenses L4 and L3, and further reflected by the dichroic mirror 30 at a substantially right angle and is incident on the condensing lens L5. This operation is the same when the second phosphor region 56 emits green band light Lg.

  In this way, R, G, and B laser beam bundles are sequentially generated using the blue-band laser light source and directed from the light tunnel 70 to a digital mirror device (DMD) or the like. Although not shown in detail here, the DMD has a plurality of mirror elements formed in a two-dimensional array, and each mirror element is tilted to the first angle or the second angle according to the digital image data and reflected by the DMD. The R, G, and B light generated generates a projection image.

  Thus, according to the present embodiment, the phosphor wheel 50 reflects all of R, G, and B, and the dichroic mirror 30 and the reflection mirror 40 selectively reflect R, G, and B light. Since it did in this way, the optical member required for the illumination optical system 10 can be reduced, and a compact structure can be obtained. In particular, the dichroic mirror 30 and the reflection mirror 40 are arranged so as to overlap in the same direction, and the rear group lenses L3 and L4 are interposed between the dichroic mirror 30 and the phosphor wheel 50, so that space saving is achieved. More promoted.

  Next, a second embodiment of the present invention will be described. FIG. 5 is a diagram showing the principle of the illumination optical system 10A according to the second embodiment. In the second embodiment, two sets of the dichroic mirror 30, the reflection mirror 40, and the rear group lens L used in the first embodiment are provided, and R, G, and B are respectively obtained from two beam bundles separated by the beam splitter. Generated and synthesized at the end. However, a plurality of phosphor wheels are used instead of a single one, and two sets of reflection regions and first and second phosphor regions are formed on the surface in the circumferential direction. Further, the rear lens group L is constituted by a single lens.

  As shown in the figure, the parallel light bundles Lb from the front lens groups L1 and L2 are separated into two light bundles Lb1 and Lb2 by the beam splitter 200. As for the separated light bundle Lb1, as in the first embodiment, R, G, and R via the dichroic mirror 30, the rear group lens L, the phosphor wheel 50A, the dichroic mirror 30 or the reflection mirror 40 are used. The B light is incident on the condenser lens L5. As shown in FIG. 5B, the light beam Lb1 is focused on the outer peripheral side of the phosphor wheel 50A, and the reflection region 52, the first and second phosphor regions 54, 56 are optically moved at the spot P. Scan.

  The other light beam Lb2 is reflected substantially at right angles by the reflecting mirror 210 and is made parallel to the light beam Lb1. The center of the reflection mirror 210 or the optical axis C4 is shifted from the optical axis C2 of the rear group lens LA, and the light beam Lb2 is incident on one half of the rear group lens LA via the dichroic mirror 30A. The incident light bundle Lb2 is focused on the spot Q on the inner peripheral side of the phosphor hole 50A by the rear group lens LA, and the reflection region 82 and the first and second phosphor regions 84 and 86 are optically reflected by the spot Q. To scan. The light Lb2 in the blue band reflected by the phosphor wheel 50A is reflected almost at right angles by the reflecting mirror 40A via the dichroic mirror 30A, and the light in the red band and the green band reflected by the phosphor wheel 50A is The light is reflected at a substantially right angle by the dichroic mirror 30A and enters the condenser lens L5. FIG. 5C represents the combined luminance when the luminances of R, G, and B of the spot P and the spot Q are combined. The arrangement of the reflection region 52 on the outer peripheral side on the phosphor wheel 80A, the first and second phosphor regions 54 and 56, the reflection region 82 on the inner peripheral side, and the first and second phosphor regions 84 and 86 The arrangement is adjusted so that the timings at which R, G, and G are generated are synchronized.

  FIG. 6 shows the relationship between the emission conversion amount of the phosphor and the irradiation energy density of the excitation light. As characteristics of the phosphor, a linear region in which the luminescence conversion efficiency increases (conversion efficiency is constant) with increasing light irradiation energy density, a saturated region in which the luminescence conversion amount is saturated (conversion efficiency decreases), and luminescence conversion amount. Is known to have a degradation region in which the degradation occurs. For this reason, when the first and second phosphor layers 54, 56, 84, 86 are irradiated with blue light having a certain energy or more, the light emission conversion amount is saturated or deteriorated, and the phosphor is thermally damaged or deteriorated. Resulting in. In order to prevent thermal damage or the like, it is necessary to cool the phosphor layer or phosphor wheel. Furthermore, the phosphor has a deterioration in light emission conversion efficiency even with a change with time.

  In the second embodiment, even when the irradiation energy of the blue band light as the excitation light is increased, the blue band light is divided into two, and two sets of phosphor layers are formed on the phosphor wheel. Therefore, the irradiation energy with which the phosphor layer is irradiated can be substantially halved. As a result, the phosphor can be used in a linear region, and deterioration of the light emission conversion amount can be prevented. At the same time, thermal damage or thermal deterioration of the phosphor layer can be suppressed, and the lifetime of the phosphor can be extended.

  In the second embodiment, an example in which the light bundle Lb is separated into two is shown. However, the light bundle Lb is divided into n pieces, and n sets of dichroic mirrors, reflection mirrors, lenses, and n sets of reflection areas. The illumination optical system may be formed by a phosphor wheel in which the phosphor region is formed.

Next, some structural examples of the phosphor wheel of the present embodiment will be described with reference to FIG.
FIG. 7A is a plan view of the phosphor wheel 300, and FIG. 7B is a sectional view taken along line XX. 7 (C1) to (C4) show various modifications of the first phosphor region 320, and FIGS. 7 (D1) to (D3) show various modifications of the reflection region 310. FIG.

  In FIG. 7C 1, a doughnut-shaped reflection layer 324 is formed on a base material 322 such as a disk-shaped glass or resin constituting the phosphor wheel 300, and the first fluorescence is formed on the reflection layer 324. A body 320A is formed. The first phosphor 320A emits red light when excited by blue light. Although the luminous efficiency of the phosphor is improved by providing the reflective layer 324, if the reflective layer 324 reflects all wavelengths of R, G, and B, the blue light transmitted through the first phosphor 320A can be reduced. There is a possibility that red and blue colors are mixed by being reflected by the reflective layer 324.

  Therefore, as shown in FIG. 7C2, a dichroic mirror 326 that reflects the fluorescent emission color and absorbs or transmits blue light is coated immediately below the first phosphor 320A. More preferably, a layer 326 that reflects R, G, and (Y) and transmits or absorbs blue light is formed. The same applies to the second phosphor 330. Thereby, the color mixture of the fluorescence emission color and the blue light can be prevented.

  Further, as shown in FIG. 7C3, the reflection layer 324 may be inclined so that the end portion of the base material 322A is thickened. By providing such an inclination, it is possible to prevent the blue light transmitted through the first phosphor 320A from being mixed with the fluorescent color. That is, since the blue light incident from the half surface of the lens 70 has a certain incident angle, the blue light is reflected toward the incident direction by tilting the reflective layer 324. Therefore, it does not enter the reflection mirror 60. The same applies to the second phosphor region 330.

  As shown in FIG. 7 (C4), a reflective member 328 having a height exceeding the phosphor layer 320A may be formed on the side surface of the base material 322. In this case, the blue light transmitted through the phosphor layer 320A is reflected by the reflection layer 324, but since the blue light traveling toward the reflection mirror 60 is reflected by the reflection member 328, color mixing with the fluorescent color is prevented. . The same applies to the second phosphor region 330.

  On the other hand, as shown in FIG. 7D1, the reflective region 310 that reflects blue light has a reflective layer 314 formed on the surface of the base material 312 so that the blue light is efficient regardless of the material of the base material 312. Reflected well. Further, as shown in FIG. 7D2, a diffusion region 316 may be formed on the surface of the reflection region 310. Since the blue laser light is coherent light, speckle is generated. In order to remove this, the coherent component can be removed by using a diffusing surface having irregularities. Further, as shown in FIG. 7 (D3), the reflecting surface 314 is inclined by providing an inclination so that the thickness of the base material 312A of the reflecting region 310 becomes thinner toward the end portion, so that blue light and phosphor It is possible to prevent color mixing by separating the optical axes of the emission colors as much as possible.

  Note that the phosphor wheel can be configured by one or more combinations shown in FIGS. 7C1 to 7D3.

  A further modification of the phosphor wheel is shown in FIG. As shown in FIG. 8A, a phosphor layer 410 for emitting red, green, yellow, or the like is formed on the phosphor wheel base material 400. When the surface is smooth, excitation occurs. The light beam Lb in the blue band, which is light, undergoes regular reflection on its surface (incident angle θ1 = exit angle θ2 with respect to the optical axis C2). When regular reflection occurs, the light Lb ′ is reflected by the reflection mirror 40 via the dichroic mirror 30, so that the light in the blue band is mixed with the light in the red band and the green band.

  As a countermeasure against this, as shown in FIG. 8B, a diffused surface 420 having irregularities is formed on the surface of the phosphor layer 410, thereby preventing regular reflection of light in the blue band. . Alternatively, as another countermeasure, as shown in FIG. 8C, an antireflection film 430 for preventing reflection of light in the blue band is formed on the surface of the phosphor layer 410, or as shown in FIG. As described above, it is desirable to form the transparent member 440 having the diffusion surface or the antireflection film formed on the phosphor layer 410.

  Next, a third embodiment of the present invention will be described. In the first and second embodiments, the R and G lights reflected by the dichroic mirror 30 and the B light reflected by the reflecting mirror 40 travel along the same optical path. In the embodiment, the optical axis of the reflecting mirror is shifted from the optical axis of the dichroic mirror.

  The blue band light regularly reflected by the phosphor wheel is the laser light itself, and speckles are generated. In order to suppress this, the optical axis of the reflection mirror 40 that reflects the light Lb in the blue band is shifted from the optical axis of the dichroic mirror 30, and a speckle removal optical system is provided on the optical path of the blue band light. After passing, they are combined in the same optical path by a dichroic mirror or the like.

  FIG. 9 is a diagram for explaining the principle of the third embodiment. As shown in the figure, the reflection mirror 40 is arranged such that its optical axis is shifted from the optical axis of the dichroic mirror 30. The light Lb in the blue band reflected by the reflection mirror 40 is reflected at a right angle by the reflection mirror 510 via the speckle removal optical system 500, and further, the light Lb is reflected by the dichroic mirror 520 at a right angle to collect the light. The light enters the lens L5. The dichroic mirror 520 has the same optical axis as the dichroic mirror 30, and the dichroic mirror 520 transmits the red band light Lr and the green band light Lg reflected by the dichroic mirror 30, and transmits the blue band light Lb. reflect. In this way, the speckle-removed blue band light Lb and the fluorescent lights Lr and Lg are condensed on the light tunnel 70 via the condenser lens L5.

  In the example shown in FIG. 9, the speckle removing optical system 500 is interposed between the reflecting mirror 40 and the reflecting mirror 510, but the speckle removing optical system 500 may be omitted. In this case, it is desirable that the reflecting mirror 40 be a diffusing surface, or a surface that reflects light in the blue band of the phosphor wheel be a diffusing surface.

  Next, an illumination optical system according to the fourth example of the present invention will be described. FIG. 10 is a diagram illustrating the principle of the illumination optical system 10B according to the third example. The illumination optical system 10B according to the present embodiment includes a dichroic mirror 600 that reflects the laser light Lb in the blue band from the array light source 20 (see FIG. 1) described in the first embodiment, a condensing lens 610, Phosphor wheel 620, motor 60 for rotating phosphor wheel 620, and dichroic mirror that reflects blue band laser light Lb output from phosphor wheel 620 and transmits red band and green band lights Lr and Lg 630 and a dichroic mirror 640 that reflects light Lr and Lg in the red band and green band that are fluorescently developed by the phosphor wheel 620 and transmits light in the blue band.

  A characteristic point in the present embodiment is that the phosphor wheel 620 includes two wheel members, and one wheel member 620-1 generates light in a blue band, a red band, and a green band, and the other wheel member 620. -2 effectively removes light in the blue band included in the light in the red band and green band that are fluorescently colored by -2. This prevents light in the blue band from being mixed with light in the red and green bands.

  The blue-band laser light Lb output from the array light source 20 is reflected by the dichroic mirror 600 at a substantially right angle. The laser light Lb in the blue band reflected by the dichroic mirror 600 is shifted from the optical axis of the condenser lens 610 so as to be a shift optical system, and is incident on one half of the condenser lens 610. The incident light Lb is The light is condensed on the phosphor wheel 620. As a result, the rotating phosphor wheel 620 is optically scanned with the blue band laser light Lb. As a result, the phosphor wheel 620 emits blue band light Lb, red band light Lr, and green band light. Lg is sequentially output. The blue band light Lb regularly reflected by the phosphor wheel 620 is incident on the opposite half of the condensing lens 610 and collected on the dichroic mirror 630. The dichroic mirror 630 reflects the light Lb in the blue band in a substantially right angle direction. The red band and green band lights Lr and Lg that are fluorescently colored by the phosphor wheel 620 are uniformly diffused in a Lambertian pattern and are collected by the condenser lens 610. The condensed lights Lg and Lr are transmitted through the dichroic mirrors 600 and 630 and reflected by the dichroic mirror 640 in a substantially right angle direction.

  The phosphor wheel 620 includes two first and second wheel members 620-1 and 620-2 that are rotated in synchronization with each other, and both wheel members are connected by a connecting member 622. Plan views of these wheel members 620-1 and 620-2 are shown in FIGS. The first wheel member 620-1 has substantially the same configuration as the phosphor wheel of the first embodiment, that is, the blue reflection region 620-1B that reflects light in the blue band, and the blue band. And a red fluorescent region 620-1R that emits red color light when excited by the light of the blue light, and a green fluorescent region 620-1G that emits green color light when excited by the blue band light. .

  The second wheel member 620-2 is mounted coaxially with the first wheel member 620-1, and is rotated together with the first wheel member 620-1. Preferably, the second wheel member 620-2 has a smaller radius (or diameter) than the first wheel member 620-1, and the periphery of the second wheel member 620-2 is the optical axis C1 of the condenser lens 610. The outer diameter of the second wheel member 620 is selected so as not to overlap. If the edge of the second wheel member 620-2 exists on the optical path of the light emitted from the first wheel member 620-1, the edge may be reflected. In order to solve this problem, in another preferred example, the second wheel member 620-2 ′ may have a peripheral edge that exceeds the optical axis C1 of the condenser lens 610. ), The circumferential portion of the second wheel member 620 includes a transparent region 620-2C that transmits R, G, and B light, and the transparent region 620-2C includes the light Lb in the blue band. And the light Lr and Lg in the red band and the green band that are fluorescently colored by the first wheel member.

  The second wheel member 620-2 has a blue band at positions corresponding to the blue reflective region 620-1B, the red fluorescent region 620-1R, and the green fluorescent region 620-1G of the first wheel member 620-1. Blue transmissive region 620-2B that transmits light, red transmissive region 620-2R that reflects blue band light and transmits red band light, and green transmissive region 620 that reflects blue band light and transmits green band light. -2G is formed. In a preferred embodiment, the interior angles of the blue reflective region 620-1B, the red fluorescent region 620-1R, and the green fluorescent region 620-1G are the blue transmissive region 620-2B, the red transmissive region 620-2R, and the green transmissive region 620-2G. That is, the blue band light reflected by the blue reflection area 620-1B is incident on the blue transmission area 620-2B, and the red band light fluorescently developed by the red fluorescence area 620-1R is transmitted through red. The green band light that is incident on the region 620-2R and fluorescently developed in the green fluorescent region 620-1G is incident on the green transmission region 620-2G.

  P <b> 1 on the first wheel member 620-1 in FIG. 11B represents the spot diameter of the blue band laser light Lb collected by the condenser lens 610. P2 on the second wheel member 620-2 in FIG. 11A represents the spot diameter of the light output from the first wheel member 620-1. Since the light Lr and Lg in the red band and the green band are uniformly diffused by fluorescent color development, the diameter of the spot P2 is larger than the spot diameter P2 of the light Lb in the blue band. Further, P3 shown in FIG. 11C represents the blue band light Lb incident from the condenser lens 610 to the second wheel member.

  The blue transmissive region 620-2B may be made of a transparent material that directly transmits the light Lb in the blue band reflected by the first wheel member 620-1, or may be an opening or a through hole. The red transmission region 620-2R is configured by an optical filter (for example, a dichroic mirror or a dichroic filter) that transmits the fluorescently colored red band light and reflects at least the blue band light. The green transmission region 620-2G is configured by an optical filter (for example, a dichroic mirror or a dichroic filter) that transmits the fluorescently colored green band light and reflects at least the blue band light. For example, the second wheel member 620-2 is affixed with an optical film or an optical mirror that transmits light in the red band and the green band on the glass substrate, or such an optical filter on the glass substrate. It can be formed by vapor-depositing the constituent material.

  The red fluorescent region 620-1R and the green fluorescent region 620-1G fluorescently develop red band light and green band light excited by the blue band laser light Lb, but the conversion efficiency of the blue band light Lb is 100. %is not. That is, part of the laser light Lb in the blue band is regularly reflected on the surface of the red fluorescent region 620-1R, and further, part of the laser light Lb that has traveled inside the red fluorescent region 620-1R becomes fluorescent. Reflected from the surface of the red fluorescent region 620-1R without being used. The same applies to the green fluorescent region 620-1G. As a result, when the fluorescence-colored red band light is output from the first wheel member 620-1, the blue-band light regularly reflected on the surface thereof and the blue-band light not used for the fluorescence color development. Are also output at the same time. Even when the green band light is output, the blue band light regularly reflected on the surface and the blue band light not used for fluorescence development are simultaneously output.

  FIG. 12 is a graph illustrating blue band light included when green band light is output. The vertical axis represents the light intensity ratio, and the horizontal axis represents the angle formed with the surface of the phosphor wheel (perpendicular to the surface). Direction is 90 degrees). However, FIG. 12 shows the light component of the green band when the phosphor wheel includes only the first wheel member, and is output from the phosphor wheel including the second wheel member as in this embodiment. It should be noted that it does not represent the light component of the green band.

  As shown in FIG. 12, it can be seen that the light Lg in the green band that is fluorescently developed from the phosphor wheel becomes light that is uniformly diffused in a Lambertian shape, and therefore has little angle dependency. The uniformly diffused green band light Lg is condensed by the condenser lens 610. On the other hand, the undesired blue band light Ln output from the phosphor wheel is converted into a fluorescent color within the fluorescent region and the angle-dependent light component regularly reflected on the surface of the fluorescent region as described above. A synthesis of components of diffused light that were not utilized. For this reason, the undesired blue band light Ln has an angle-dependent light intensity, that is, a large light intensity in the vicinity of the direction of regular reflection (in the vicinity of an angle of 90 degrees). Lg + Ln represents the intensity when the light of both components is combined.

  In the present embodiment, the phosphor wheel 620 includes a second wheel member 620-2 for cutting the blue band light Ln in order to effectively remove such unwanted blue band light Ln. . The green band light Lg output from the green fluorescent region 620-1G of the first wheel member 620-1 passes through the green transmissive region 620-2G of the second wheel member 620-2, but the green band light. Undesired blue band light Ln included in Lg is reflected by the green transmission region 620-2G. Similarly, the red band light Lr output from the red fluorescent region 620-1R passes through the red transmission region 620-2R, but the undesired blue band light Ln included in the red band light Lr is red. Reflected by the transmissive region 620-2R.

  FIG. 13 is a graph showing components of the green band light Lg output from the dichroic mirrors 630 and 640 when the second wheel member 620-2 according to the present embodiment is provided. The light intensity of the green light Lg that is fluorescently colored is almost the same, but of the unwanted blue band light Ln, it is used for regularly reflected light within a range of about 0 to 90 degrees, and for fluorescent color development. The missing light component is removed by the second wheel member 620-2. Further, the undesired blue band light Ln within the range of about 90 to 180 degrees is transmitted through the second wheel member 620-2, but the light is reflected by the dichroic mirror 600 and is dichroic mirror 640. Therefore, the green band light Lg is not mixed. This principle is the same for the red band light Lr. As described above, in this embodiment, it is possible to effectively prevent the light Ln in the undesired blue band from being mixed with the light in the red band and the green band that are fluorescently colored.

  Next, various modifications of the second wheel member will be described. In the above example, the function of the second wheel member 620-2 is mainly to prevent the color mixing of the light in the blue band, but the second wheel member can be used for each of R, G, and B at the same time. A function of correcting the color can be provided.

  The blue transmissive region 620-2B formed in the second wheel member 620-2 has been shown as an example of an opening or a through-hole. However, when a color correction function is provided, the blue transmissive region 620- 2B includes an optical filter or an optical mirror that transmits the selected wavelength range λb1 to λb2 in the blue band. Similarly, the red transmissive region 620-2R and the green transmissive region 620-2G are configured by optical filters or optical mirrors that transmit the selected wavelength ranges λr1 to λr2 and λg1 to λg2, respectively. For example, as shown in FIG. 14, the blue transmission region 620-2B selectively transmits the 450 nm band, the red transmission region 620-2R selectively transmits the 630 nm band, and the green transmission region 620-2G It is configured to selectively transmit the 520 nm band. If the phosphor wheel 620 includes a fluorescent region that fluoresces yellow band light, the yellow transmission region of the second wheel member is configured to selectively transmit the 550 nm band.

  Moreover, in the said Example, although the 2nd wheel member 620-2 was adjoined to the 1st wheel member 620-1 and the example arrange | positioned at the entrance plane side of the condensing lens 610 was shown, the 2nd wheel was shown. The member 620-2 may be inserted at an arbitrary position as long as it is on the optical path of the red band and the green band. FIG. 15 shows an example in which the second wheel member 620-2 is disposed between the condenser lens 610 and the dichroic mirror 630. Also in this case, the first and second wheel members 620-1 and 620-2 are coupled by the connecting member 622 and are simultaneously rotated.

  FIG. 16 shows another configuration example of the illumination optical system of the present embodiment. When the second wheel member 620-2 is disposed between the condensing lens 610 and the dichroic mirror 630, the spot diameter of the light incident on the second wheel member 620-2 is increased, and accordingly. Light loss increases. Therefore, as shown in FIG. 16, the second wheel member 620-2 is disposed between the two condenser lenses 650 and 660, and the spot diameter of the light incident on the second wheel member 620-2 is reduced. By doing so, it becomes possible to suppress the loss of the light amount.

  FIG. 17 shows another modification of the second wheel member. As shown in FIG. 17A, the second wheel member 620-2 includes a plurality of sets of transmission regions in the radial direction. In the illustrated example, the first set on the outermost periphery includes a first blue transmission region 620-2B, a green transmission region 620-2G, and a red transmission region 620-2R. A second blue transmissive region 620-2B ′, a green transmissive region 620-2G ′, and a red transmissive region 620-2R ′ are included. For example, the first set and the second set of transmission regions are configured to select different wavelength bands.

  The phosphor wheel 620 is movable in the horizontal direction H as shown in FIG. 17B, and when the phosphor wheel 620 is at the position d1, the light emitted from the first wheel member 620-1 is When the first set of transmission regions of the second wheel member 620-2 are irradiated with the spot P2 and the phosphor wheel 620 is at the position d2, the light emitted from the first wheel member 620-1 is second. The second transmission region of the wheel member 620-2 is irradiated with the spot P2 ′. By enabling such switching, it is possible to easily select or fine-tune the colors of R, G, and B.

  In the above embodiment, an example is shown in which the side on which the laser light Lb from the array light source 20 is incident and the side on which the laser light Lb, Lr, and Lg are emitted face each other, as shown in FIG. Of course, if the direction of the dichroic mirror 600 is reversed, the incident side of the laser beam Lb and the emission side of the laser beams Lb, Lr, and Lg can be made the same side. Further, by using other optical systems, those skilled in the art can understand that the incident direction of the laser beam Lb and the emitting directions of the laser beams Lb, Lr, and Lg can be appropriately changed. In the above embodiment, the dichroic mirror 630 is disposed on the front side and the dichroic mirror 640 is disposed on the rear side. However, this order may be reversed. Furthermore, the illumination optical system according to the fourth embodiment can of course be used in combination with the illumination optical system described in the first to third embodiments.

  Moreover, in the said Example, although the 1st wheel member 620-1 showed the example which reflects the light Lb of blue band toward the 2nd wheel member side, it is not restricted to this, The light Lb of blue band is The first wheel member 620-1 may be transmitted. In this case, the blue reflection region 620-1B of the first wheel member 620-1 is made of a material that transmits the light lb in the blue band, or a through hole or opening. FIG. 19 shows an illumination optical system when the first wheel member 620-1 transmits the light Lb in the blue band. The light Lb in the blue band that has passed through the first wheel member 620-1 is extracted in a desired direction by, for example, the total reflection mirror 630A.

  Next, a fifth embodiment of the present invention will be described. In the above embodiment, the phosphor wheel outputs an example of outputting a plurality of lights excited by the laser beam in the blue band (in the above embodiment, the light in the red band and the light in the green band). In the embodiment, single light is fluorescently colored by the first wheel member, and a plurality of lights are separated or extracted from the fluorescently colored light by the second wheel member. In a preferred embodiment, the first wheel member includes a blue generation region that reflects or transmits the blue band laser light Lb from the array light source, and the yellow band light by being excited by the blue band laser light Lb. And a yellow fluorescent region that fluoresces. A fluorescent substance that develops light in the yellow band has a relatively higher conversion efficiency than a fluorescent substance that develops fluorescence in the red or green band, and thus has an advantage of high output of light in the yellow band. However, in the present invention, the fluorescent material is not limited to the yellow band, but may be another band, cyan, or magenta.

  FIG. 20 is a diagram showing an illumination optical system according to the fifth example of the present invention. In the illumination optical system 10C according to the fifth example, as described above, the phosphor wheel 720 includes the first wheel member 720-1 that outputs a single fluorescent color, and a plurality of single fluorescent colors. And a second wheel member 720-2 for separating or extracting light in the wavelength band. Other configurations are the same as those in FIG. 10 (fourth embodiment), and thus the description thereof is omitted. FIG. 20B is a partially enlarged view of the phosphor wheel 720, and the first and second wheel members 720-1 and 720-2 have substantially the same diameter. The center of rotation of the phosphor wheel is C6, the radius from the center C6 to the edge of the first and second wheel members 720-1 and 720-2 is r1, and the light Lb in the blue band passes through the first wheel member 720-1. The radius from the approximate center of the spot diameter when irradiated to the rotation center C6 is r2, and the radius from the rotation center C6 to the edge of the region for selecting the wavelength of the second wheel member 720-2 is r3. Reference numeral 722 denotes a connecting member for the first and second wheel members 720-1 and 720-2.

  FIG. 21A is a plan view of the first wheel member, and FIG. 20B is a plan view of the second wheel member. The first wheel member 720-1 is formed with a blue reflective region 720-1B that reflects light in the blue band and a yellow fluorescent region 720-1Y that is excited by the light in the blue band and emits fluorescence in the yellow band. Is done. Therefore, the laser light Lb from the array light source 20 optically scans the blue reflection region 720-1B and the yellow fluorescent region 720-1Y of the rotated first wheel member 720-1, and the first wheel member 720 is scanned. From -1, blue band light and yellow band light are sequentially output.

  The second wheel member 720-2 includes a blue transmission region 720-2B that transmits blue band light from the array light source and blue band light from the blue reflection region 720-1B, and a yellow band light to red band light. It includes a red color generation region 720-2R that generates light and a green color generation region 720-2G that generates light in the green band from light in the yellow band.

The blue transmissive region 720-2B is made of, for example, an opening or a through-hole, or a transparent material that transmits at least blue band light. The red color generation region 720-2R includes at least two regions having different characteristics. That is, the red generation region 720-2R is configured by an optical filter that transmits blue band light and transmits red band light included in the yellow band in the region between r1 and r2, and is a region between r2 and r3. Is configured by an optical filter that reflects light in the blue band, reflects light in the green band included in the yellow band, and transmits light in the red band included in the yellow band.
The green generation region 720-2G includes an optical filter that transmits blue band light in the region between r1 and r2 and transmits green band light included in the yellow band, and blue in the region between r2 and r3. The optical filter reflects light in the band, reflects light in the red band included in the yellow band, and transmits light in the green band included in the yellow band.

  As described above, according to the fifth embodiment, it is possible to obtain R, G, and B light using a fluorescent material having a high intensity of fluorescent color and having little color mixing. The fifth embodiment of the present invention can be combined with the first to fourth embodiments, and the technique described therein can be applied.

  Next, a sixth embodiment of the present invention will be described. The illumination optical system 10D of the present embodiment includes front group lenses L1 and L2 that condense blue band laser light Lb as excitation light emitted from an array light source (see FIG. 2), and front group lenses L1 and L2. A first beam splitter BS1 that transmits part of the laser beam Lb collected by the laser beam and reflects the remainder in a right angle direction, and a first dichroic mirror that transmits blue band light and reflects at least red band light. 820, a condenser lens L3, a second beam splitter BS2 that transmits part of the laser light Lb reflected by the first beam splitter BS1, and reflects the rest in a right angle direction, and light in the blue band and red A second dichroic mirror 830 that transmits light in the band and reflects light in the green band; a condenser lens L4; and transmits light in the blue band and light in the red band and green band. A third dichroic mirror 840 that reflects, a reflecting mirror 850 that reflects at least light in the red band and green band, a phosphor wheel 860 disposed at a position facing the condenser lenses L3 and L4, and a phosphor wheel 860 And a drive motor 870 that rotationally drives the motor.

  The front group lens L1 is composed of, for example, a convex lens, the front group lens L2 is composed of, for example, a concave lens, and the front group lenses L1, L2 condense the laser beam Lb from the array light source into parallel light. The optical axis C1 of the front group lenses L1 and L2 is the center of the lenses L1 and L2. In this example, two combination lenses are used as the front group lens. However, the front group lens only needs to be an optical system capable of condensing the laser light Lb from the array light source, and constitutes the front group lens. The number of lenses may be one, or three or more. Further, the front lens group may be composed of either a spherical lens or an aspheric lens. Further, the front lens group may include an optical member such as a prism.

  The first beam splitter BS1 is disposed on the optical axis C1, transmits a part of the laser light Lb, for example, 1/3 light in the direction of the optical axis C1, and transmits the remaining 2/3 light to the optical axis. Reflects in a direction perpendicular to C1.

  The first dichroic mirror 20 is disposed on the optical axis C1, and transmits the laser light Lb transmitted through the first beam splitter BS1 in the direction of the optical axis C1. As will be described later, the first dichroic mirror 820 reflects the light in the red band emitted by the phosphor wheel 860 in the direction of the optical axis C4 orthogonal to the optical axis C1.

  The condenser lens L3 is disposed between the first dichroic mirror 820 and the phosphor wheel 860, and the center of the condenser lens L3 coincides with the optical axis C1. The condensing lens L3 condenses the laser light Lb transmitted through the first dichroic mirror 820 on the phosphor wheel 860. Further, the red band light Lr emitted by the phosphor wheel 860 is condensed on the first dichroic mirror 820. In the example shown in the figure, the condensing lens L3 is configured by using one lens, but the condensing lens L3 condenses the laser light Lb on the phosphor wheel 860 and is emitted from the phosphor wheel 860. As long as it is an optical system that can collect the light Lr, the number of lenses constituting the condenser lens L3 may be a plurality of combination lenses. Further, the condensing lens L3 may be composed of either a spherical lens or an aspheric lens. Furthermore, the condensing lens may include an optical member such as a prism.

  The second beam splitter BS2 is disposed on the optical axis C3 orthogonal to the optical axis C1, and a part of the laser light Lb reflected by the first beam splitter BS1, for example, 1/3 light is applied to the optical axis C3. And the remaining 2/3 of the light is reflected in a direction orthogonal to the optical axis C3.

  The second dichroic mirror 830 is disposed on the optical axis C4, transmits the laser light Lb reflected by the second beam splitter BS2 in a direction orthogonal to the optical axis C4, and reflects by the first dichroic mirror 820. The red light Lr thus transmitted is transmitted in the direction of the optical axis C4. As will be described later, the second dichroic mirror 830 reflects the light in the green band emitted by the phosphor wheel 860 in the direction of the optical axis C4.

  The condenser lens L4 is disposed between the second dichroic mirror 830 and the phosphor wheel 860, and the optical axis C2 of the condenser lens L4 is the center of the condenser lens L4. The optical axis C2 is parallel to the optical axis C1. The condensing lens L4 condenses the laser light Lb transmitted through the second dichroic mirror 830 on the phosphor wheel 860, and the green band light Lg emitted by the phosphor wheel 860 on the second dichroic mirror 830. Condensed to In the illustrated example, the condensing lens L4 is configured by using one lens, but the condensing lens L4 condenses the laser light Lb on the phosphor wheel 860 and has a green band from the phosphor wheel 860. Any optical system that can collect the light Lg may be used, and the number of lenses constituting the condenser lens L4 may be a plurality of combination lenses. Further, the condensing lens L4 may be constituted by either a spherical lens or an aspheric lens. Furthermore, the condensing lens may include an optical member such as a prism.

  The reflection mirror 850 reflects the red band light Lr transmitted through the second dichroic mirror 30 and the green band light Lg reflected by the second dichroic mirror 830 in a direction orthogonal to the optical axis C4.

  The third dichroic mirror 840 is disposed on the optical axis C3, transmits the laser light Lb transmitted through the second beam splitter BS2 in the direction of the optical axis C3, and is reflected by the reflection mirror 850 and is reflected in the red band and the green band. Are reflected in the direction of the optical axis C3. Thereby, R, G, and B light is extracted from the third dichroic mirror 840, and white light can be obtained by synthesizing the light. The white light emitted from the third dichroic mirror 840 is then separated into R, G, and B, and can be used, for example, as a light source for a liquid crystal projector. In the example of FIG. 22, R / G / B light is extracted in the direction of the optical axis C3. However, in the direction orthogonal to the optical axis C3 using an optical member such as a mirror, or any other direction. R / G / B light can be extracted.

  Next, the phosphor wheel will be described. The phosphor wheel 860 is disposed at a position facing the condenser lenses L4 and L5, and emits light in the red band and the green band when irradiated with the blue laser light Lb. The surface of the phosphor wheel 860 is excited by the blue band laser light and emits red band light, and the annular first phosphor region 862R is excited by the blue band laser light and emits the green band light. An annular second phosphor region 862G that emits light is formed. The first and second phosphor regions 862R and 862B are arranged concentrically, and in the example shown in the figure, the first phosphor region 862R is formed on the outer peripheral side with respect to the second phosphor region 862G. This relationship may be the opposite.

  The first phosphor region 862R has a certain width in the radial direction, and preferably the center of the radial width coincides with the optical axis C1. The condensing lens L3 adjusts the size of the spot P of the laser light Lb so that the laser light Lb in the blue band falls within the width of the first phosphor region 862R. Similarly, the second phosphor region 862G has a constant width in the radial direction, and preferably the center of the radial width coincides with the optical axis C2. The condenser lens L4 adjusts the size of the spot Q of the laser beam Lb so that the laser beam Lb in the blue band falls within the width of the second phosphor region 862G.

  The phosphor wheel 860 is rotated at a constant speed by a driving motor 870, and the first and second phosphor regions 862R and 862G are optically continuously scanned by the spots P and Q. The first phosphor region 862R emits red band light Lr excited by the laser light Lb in a Lambertian shape (uniform diffusion). The emitted light Lr is condensed on the first dichroic mirror 820 by the condenser lens L3, and is reflected in the direction of the optical axis C4 orthogonal to the optical axis C1. The second phosphor region 862G emits the green band light Lg excited by the laser light Lb in a Lambertian shape (uniform diffusion). The emitted light Lg is condensed by the condenser lens L4 onto the second dichroic mirror 830, where it is reflected in the direction of the optical axis C4 orthogonal to the optical axis C2.

  Examples of the phosphor material constituting the first and second phosphor regions 862R and 862G include YAG (yttrium, aluminum, garnet), TAG (terbium, aluminum, garnet), sialon, BOS (barium Orthosilicate) and nitride compounds are known. The first and second phosphor regions 862R and 862G are, for example, sheet-like ones obtained by applying a mixture of a phosphor material and a resin material or a ceramic material on the surface of the base material, or mixing a phosphor material. And may be affixed to the substrate surface.

  FIG. 23A is a plan view of the phosphor wheel, and FIG. 23B is a cross-sectional view of the phosphor wheel taken along line XX. Circles indicated by P and Q in the figure represent spots of light Lb in the blue band collected by the condenser lenses L3 and L4.

  The phosphor wheel 860 includes a reflective layer 864 that reflects light in the blue band, the red band, and the green band on the surface of the disc-shaped support substrate 866, and first and second phosphors formed on the reflective layer 864. Regions 862R and 862G. The material of the support substrate 866 is not particularly limited, and is made of, for example, a metal material, a resin material, a glass material, or the like. Note that since the temperature of the phosphor wheel 860 is increased by irradiation with the laser light Lb, the support substrate 866 desirably has a material or a shape excellent in heat dissipation characteristics. The support substrate 866 is preferably circular, but is not necessarily limited to such a shape, and may be, for example, a polygonal or elliptical shape.

  When the first phosphor region 862R is irradiated with the laser light Lb, the phosphor material is excited by the laser light Lb, and the red band light Lr is emitted. Since the red band light Lr isotropically diffuses in a Lambertian shape from the light emitting point, a part of the light travels toward the support substrate 866. However, since such light Lr is reflected by the reflective layer 864 without being transmitted to the back side of the phosphor wheel 860, the red band light Lr can be efficiently extracted. Similarly, the green band light Lg emitted from the second phosphor region 862B is also reflected by the reflective layer 864, so that the green band light Lg can be efficiently extracted.

  A part of the light Lb in the blue band does not contribute to wavelength conversion of the red band and the green band in the first and second phosphor regions 862R and 862G, and the first and second phosphor regions 862R, Some of them pass through 862G. However, such transmitted laser light Lb is reflected by the reflective layer 864 and returned again to the first and second phosphor regions 862R and 862G, and is used for wavelength conversion. Can be improved.

  Furthermore, as shown in FIG. 23C, an antireflection film that prevents reflection of light in the blue band Lb on the entire surface of the phosphor wheel 860 or on the first and second phosphor regions 862R and 862G. 868 can be formed. Thereby, the light Lb in the blue band is suppressed from being reflected from the surfaces of the first and second phosphor regions 862R and 862G, and the conversion efficiency by the phosphor can be improved.

  Thus, according to the present embodiment, it is possible to generate light in the red band and the green band by using the light in the blue band emitted from the array light source. By appropriately selecting the phosphor material formed on the phosphor wheel, the light subjected to wavelength conversion can be light in the yellow band or other bands. Furthermore, since the blue band light Lb is laser light itself and coherent light, speckles are generated. As a measure against this speckle, an optical member such as a diffusion plate can be installed on the optical path of the laser beam in the blue band. The diffusing plate includes, for example, a diffusing surface having irregularities formed on the surface, and can remove or alleviate the coherent component. For example, a diffusion surface can be formed on the surface of the first beam splitter, or a speckle removal optical system can be added on the optical path of the laser light Lb.

  Further, in the above embodiment, as shown in FIG. 23, an example in which the phosphor wheel 60 is optically scanned at the positions of the spots P and Q has been shown, but the blue band to be divided by adding a beam splitter or the like. It is possible to further increase the number of the light beams Lb (for example, four) and increase the number of spots P and Q. In this case, it is necessary to add an optical system for collecting R and G light emitted by irradiation of the added spots P and Q. On the other hand, the phosphor material of the phosphor wheel 860 is heat or the like. Therefore, the irradiation energy of one spot can be reduced and the life of the phosphor wheel can be improved by increasing the number of divisions of the laser beam Lb.

  Next, the principle of the illumination optical system according to the seventh example of the present invention will be described with reference to FIG. In the first illumination optical system 10E, the phosphor wheel 860 is configured to reflect the light in the red band and the green band excited by the light in the blue band from the incident surface side. 10E is configured to emit red band and green band light excited by blue band light from the exit surface side. The same components as those shown in FIG. 22 are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 24, the surface of the phosphor wheel 860A is irradiated with the laser light Lb in the blue band by the condenser lens L3. The laser light Lb is incident on the first phosphor region 862R formed on the emission surface side of the phosphor wheel 860A, and excites the red band light there. As a result, red band light Lr is emitted in a Lambertian shape from the emission surface side of the phosphor wheel 860A. Similarly, the blue band light condensed by the condenser lens L4 irradiates the second phosphor region 862G, and the green band light excited by the second phosphor region 862G is emitted from the phosphor wheel 860A. The light is emitted from the surface side.

  FIG. 25 is a schematic sectional view showing the structure of the phosphor wheel according to the eighth embodiment. The phosphor wheel 860A transmits the blue band light and reflects the red band and green band light, and the first and second phosphor regions 862R and 862G formed on the back surface of the dichroic mirror 864A. And have. The blue band light Lb is incident on the first phosphor region 862R via the dichroic mirror 864A, and the red band light Lr excited there is emitted from the emission surface side of the phosphor wheel 860A. A part of the red band light Lr is reflected by the dichroic mirror 864A and emitted from the emission surface side of the phosphor wheel 860A. Similarly, the light in the green band excited by the second phosphor region 862G is extracted from the emission surface side of the phosphor wheel 860A.

  The red band light Lr emitted from the emission surface side of the phosphor wheel 860A is collected by the condenser lens L5 and then reflected in the optical axis C4 direction by the reflection mirror 820A that reflects at least the red band light. . The reflection mirror 820A may be composed of a dichroic mirror as in the sixth embodiment. The green band light Lb emitted from the emission surface side of the phosphor wheel 860A is collected by the condenser lens L6 and then reflected by the second dichroic mirror 830 in the direction of the optical axis C4. Thus, the third dichroic mirror 840 emits R / G / B light in the direction of the optical axis C3.

  Next, another method for separating laser light is shown in FIG. In the illumination optical systems shown in FIGS. 22 and 24, the laser light is separated by the beam splitter, but the laser light can be separated by using other optical systems. As shown in FIG. 26, when the laser light Lb travels toward the optical axis C, the two convex lenses 900 and 910 are arranged so that the optical axes are parallel to the optical axis C, and the laser light Lb. Is incident on one half of each of the lenses 900 and 910. Thereby, the laser beam Lb is condensed by the lenses 900 and 910, respectively, and separated into the laser beams Lb1 and Lb2. If the sizes of the lenses 900 and 910 are the same and the lenses 900 and 910 are arranged symmetrically with respect to the optical axis C, the laser beam Lb is separated into ½ laser beams Lb1 and Lb2, respectively.

  Next, a modification of the sixth embodiment will be described with reference to FIG. In the sixth and seventh embodiments, an example in which light in a blue band, a red band, and a green band is combined has been shown, but the present invention is not limited to such an illumination optical system. That is, as shown in FIG. 27, the illumination optical system 10F of the present invention may be configured to extract R, G, and B light individually.

  In the illumination optical system 10F shown in FIG. 27, the first dichroic mirror 820 rotates the direction in FIG. 22 by 180 degrees. Therefore, the red band light Lr emitted from the phosphor wheel 860 is reflected by the first dichroic mirror 820 in the direction of the optical axis C4. That is, the light Lr in the red band is reflected in a direction 180 degrees opposite to that in FIG. Further, as shown in FIG. 27, if the reflection mirror 850 and the third dichroic mirror 840 are omitted, the light Lb in the blue band and the light Lg in the green band can be extracted individually. As will be apparent to those skilled in the art, the individually extracted blue band light Lb, red band light Lr, and green band light Lg may be obtained using an optical system such as a lens, mirror, or prism. It is possible to be directed in the direction of or to synthesize their light.

  In the above embodiment, the phosphor wheel 860 / 860A is formed with the first and second phosphor regions 862R and 862G for emitting light in the red band and the green band, but is excited by the blue laser light. The light subjected to wavelength conversion is not necessarily limited to light in the red band and green band. For example, it may include a phosphor layer that excites light in the yellow, magenta, and cyan bands. A dichroic mirror is synonymous with a dichroic filter, and a reflective layer, a reflective mirror, and an antireflection film are synonymous with a reflective member, a reflective filter, and the like.

  The illumination optical system according to the present invention can be applied to light sources of various electronic devices. For example, it can be used for a light source such as a projector, a rear projector, an endoscope, and an illumination device.

  The preferred embodiment of the present invention has been described in detail above, but the present invention is not limited to the specific embodiment, and various modifications can be made within the scope of the present invention described in the claims. Deformation / change is possible.

10, 10A, 10B, 10C: illumination optical system, 20: array light source, 30, 30A: dichroic mirror, 40: reflection mirror, 50, 50A: phosphor wheel, 52, 82: reflection region, 54, 84: phosphor Region (R), 56, 86: Phosphor region (G), 60: Motor, 70: Light tunnel, 200: Beam splitter, 210: Reflecting mirror, L1, L2: Front group lens, L3, L4: Rear group lens , L5: condenser lens, 312, 322: base material, 316: diffusing surface, 324, 314: reflective layer, 326: dichroic mirror, 328: reflective member, 600: dichroic mirror, 610: condenser lens, 620: fluorescence Body wheel, 620-1: first wheel member,
620-1B: Blue reflection region, 620-1R: Red fluorescence region, 620-1G: Green fluorescence region,
620-2: second wheel member, 620-2B: blue transmission region, 620-2R: red transmission region, 620-2G: green transmission region, 630: dichroic mirror, 640: dichroic mirror, 720: phosphor hole, 720-1: First wheel member, 720-1B: Blue reflection region, 720-1Y: Yellow fluorescent region, 720-2: Second wheel member, 720-2B: Blue transmission region, 720-2R: Red color generation Area, 720-2G: Green generation area

Claims (25)

A wavelength conversion device used in an illumination optical system,
Including a wavelength conversion region that emits light having a wavelength different from that of the blue band based on incident blue band light, and one wavelength conversion region is formed concentrically around the rotation center, and the wavelength conversion region is formed in a radial direction. A wavelength conversion device in which n sets (n is an integer of 2 or more) are formed. The one wavelength conversion region includes: a first phosphor region that emits red band light based on blue band light; and a second phosphor region that emits green band light based on blue band light. The wavelength conversion device according to claim 1, comprising: The first phosphor region and the second phosphor region are arranged so that the light in the red band and the light in the green band emitted from each wavelength conversion region of the n sets of wavelength conversion regions are respectively synchronized. The wavelength conversion device according to claim 2. The wavelength conversion device according to claim 1, wherein the wavelength conversion region includes a region that reflects light in a blue band. The wavelength conversion device according to claim 4, wherein an absorption region that absorbs light in a blue band is formed on the back surfaces of the first and second phosphor regions. The wavelength conversion device according to claim 4, wherein a transmissive region that transmits light in a blue band is formed on the back surfaces of the first and second phosphor regions. The wavelength conversion device according to any one of claims 1 to 6, wherein a reflection region for reflecting light in a red band and a green band is formed on the back surfaces of the first and second phosphor regions. 6. The wavelength conversion device according to claim 4, wherein a diffusion surface for diffusing light in a blue band is formed on the surfaces of the first and second phosphor regions. The wavelength conversion device according to claim 46, wherein the reflective region is inclined toward a peripheral direction. A reflective region that reflects light in the first wavelength band, a first phosphor region that emits light in the second wavelength band based on at least light in the first wavelength band, and light in the third wavelength band are emitted. A first rotating member including a second phosphor region;
A first transmission region that transmits light in the first wavelength band reflected from the reflection region; a second transmission region that transmits light in the second wavelength band output from the first phosphor region; And a second rotating member including a third transmission region that transmits light in the third wavelength band output from the second phosphor region,
Including wavelength conversion device. The wavelength conversion device according to claim 10, wherein the second transmission region reflects light in the first wavelength band, and the third transmission region reflects light in the first wavelength band. The second transmission region transmits a wavelength selected from a second wavelength band, and the third transmission region transmits a wavelength selected from a third wavelength band. The wavelength conversion device according to 10 or 11. 13. The wavelength conversion according to claim 10, wherein the second rotating member includes n sets in the radial direction including a first transmission region, a second transmission region, and a third transmission region. device. The wavelength conversion device according to claim 10, wherein the first wavelength band is a blue band, the second wavelength band is a red band, and the third wavelength band is a green band. A first rotating member that includes a reflective region that reflects light in the first wavelength band, and a first phosphor region that emits light in the second wavelength band based on at least light in the first wavelength band;
A first transmission region that transmits light in the first wavelength band reflected from the reflection region, and light in a third wavelength band from light in the second wavelength band that is output from the first phosphor region. A second rotating member including a first extraction region to be extracted and a second extraction region for extracting light in the fourth wavelength band from light in the second wavelength band;
Including wavelength conversion device. 16. The first extraction region includes a region that reflects light in a first wavelength band, and the second extraction region includes a region that reflects light in a first wavelength band. Wavelength conversion device. The first wavelength band is a blue band, the second wavelength band is a yellow band, the third wavelength band is a red band, and the fourth wavelength band is a green band. The wavelength conversion device according to 15 or 16. The wavelength conversion device according to any one of claims 1 to 9,
And an optical system that makes n sets of light beams in the blue band incident on the wavelength conversion device. 19. The illumination optical system according to claim 18, wherein the optical system includes n sets of lenses that collect a light flux in a blue band in each of the n sets of wavelength conversion regions. The illumination optical system according to claim 19, wherein the optical axis of the light flux in the blue band is different from the optical axis of the lens. The illumination optical system according to any one of claims 18 to 20, wherein the optical system includes a dichroic member that transmits blue band light from a light source and reflects red band light and green band light. A wavelength conversion device according to any one of claims 10 to 17,
A first optical system for supplying light of a first wavelength band to the wavelength conversion device;
A second optical system that outputs light from the wavelength conversion device;
An illumination optical system. The illumination optical system according to claim 22, wherein the first optical axis of the first optical system is shifted from the second optical axis of the second optical system.
A projector comprising the illumination optical system according to any one of claims 18 to 23. An endoscope including the illumination optical system according to any one of claims 18 to 23.

Images