JP6251868B2 - Illumination optical system and electronic apparatus using the same - Google Patents

Description

  The present invention relates to an illumination optical system using a light source that emits light of a wavelength 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

  The light source unit as disclosed in Patent Document 1 has insufficient prevention of color mixture in the blue band, green band, and red band, and has insufficient color rendering.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an illumination optical system that prevents color mixing of output light and has improved color rendering, and an electronic apparatus using the illumination optical system.

  An illumination optical system according to the present invention includes a light source that emits light of a first wavelength band, a reflection region that reflects light of at least the first wavelength band in a circumferential direction of the first radius, and a first wavelength band. A phosphor region that emits light of a second wavelength band based on the light, and further includes a first transmission region that transmits at least the light of the first wavelength band in the circumferential direction of the second radial direction; A rotating member that includes a second transmission region that transmits light in the wavelength band; and an optical axis that is shifted from the optical axis of the principal ray in the first wavelength band that is emitted from the light source. 1st optical means which condenses the light of 1 wavelength band to the area | region of the 1st radius of the said rotation member, the light of the 1st wavelength band reflected by the said reflection area of the said rotation member, and the said fluorescent substance A second wavelength band of light emitted from the second wavelength band of the rotating member; A second optical means for condensing light in the direction area, and the light of the first wavelength band reflected by the reflection area is transmitted through the first transmission area and emitted from the phosphor area. The reflection region, the phosphor region, and the first and second transmission regions are arranged so that light in the second wavelength band is transmitted through the second transmission region.

  In a preferred embodiment, the light source includes first mirror means between the light source and the first optical means, and the first mirror means emits light of the first wavelength band emitted from the light source to the first optical means. Is substantially incident on one side of the optical axis. In a preferred aspect, the illumination optical system further includes second and third mirror means between the first optical means and the second optical means, and the second and third mirror means are the first and second mirror means. Light in the first and second wavelength bands emitted from the optical means is incident on the second optical means. In a preferred aspect, the illumination optical system further includes fourth mirror means for reflecting the light of the first wavelength band transmitted through the second mirror means toward the third mirror means, and the second mirror means The mirror means is a dichroic mirror that transmits light in the first wavelength band and reflects light in the second wavelength band. In a preferred aspect, the angle difference between the first scanning area by the first optical means and the second scanning area by the second optical means is smaller than 180 degrees. In a preferred aspect, the first transmission region includes a diffusion portion that diffuses light in the first wavelength band. In a preferred embodiment, the first wavelength band is a blue band, and the second wavelength band is either a red band, a green band, or a yellow band. In a preferred embodiment, the light in the second wavelength band is light in the yellow band, and the second transmission region is a red color that sorts light in the red band and light in the green band from the yellow band light that is fluorescently colored. Each of the transmission region and the green transmission region is included. In a preferred embodiment, an annular heat dissipating member is provided in a region corresponding to the phosphor region on the back surface of the rotating member. In a preferred embodiment, the first optical means includes at least one lens, and the second optical means includes at least one lens. In a preferred aspect, the rotating member includes a first base material and a second base material, the first base material is made of a metal, and the reflection region and the phosphor region are the first base material. The first and second transmission regions are formed on the second substrate.

  According to the present invention, color mixing of light in the first wavelength band and light in the second wavelength band output from the rotating member can be prevented, and color rendering can be improved.

It is a figure which shows the structure 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 applicable to an illumination optical system. FIG. 3A is a plan view of the phosphor wheel of the present embodiment, and FIGS. 3B and 3C are cross-sectional views taken along line XX. FIG. 4A is a diagram illustrating a state in which light in the blue band is regularly reflected by the phosphor wheel according to the present embodiment. 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 the light of a yellow zone | band is emitted. It is a top view which shows the structural example of the other fluorescent substance wheel used for the illumination optical system of a present Example. It is a top view which shows the structural example of the other fluorescent substance wheel used for the illumination optical system of a present Example. It is a top view which shows the structural example of the other fluorescent substance wheel used for the illumination optical system of a present Example. It is a top view which shows the structural example of the other fluorescent substance wheel used for the illumination optical system of a present Example. It is a top view which shows the structural example of the other fluorescent substance wheel used for the illumination optical system of a present Example. It is a top view which shows the structural example of the other fluorescent substance wheel used for the illumination optical system of a present Example. It is a figure which shows the structure of the illumination optical system which concerns on the 2nd Example of this invention. It is a figure which shows the structure of the illumination optical system which concerns on the 3rd Example of this invention. It is a figure which shows the structure of the illumination optical system which concerns on the 4th Example of this invention. It is a figure which shows the structure of the illumination optical system which concerns on the 5th Example of this invention. It is a figure which shows the structure 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. However, the illumination optical system of the present invention can be applied to various electronic devices and electronic devices such as home appliances, endoscopes, and vehicle lighting devices. 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, blue band light, and yellow band light may be abbreviated as R, G, B, and Y for convenience.

  The illumination optical system 10 of the present embodiment includes a first dichroic mirror M1 that reflects laser light from an array light source (not shown) that emits blue band laser light as excitation light, a first lens L1, and It is reflected by the disk-shaped phosphor wheel 20, the rotation drive unit 30 that rotates the phosphor wheel 20, the second mirror M2 that reflects the light emitted from the phosphor wheel 20, and the second mirror M2. A third mirror M3 that reflects the reflected light, a second lens L2 that condenses the light reflected by the third mirror M3 toward the phosphor wheel 20, and a rear surface side of the phosphor wheel 20. And the light tunnel LT. The light emitted from the light tunnel LT is guided to a spatial modulation device such as DMD, an optical fiber, or the like via a relay optical system (not shown).

  FIG. 2 is a schematic cross-sectional view showing one configuration example of the array light source. The array light source 40 includes a plurality of semiconductor laser elements (or blue light-emitting diodes) that emit blue-band laser light in an array. For example, the blue laser element outputs light having a wavelength of 445 nm. 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. As shown in FIG. 2, a substrate on which a plurality of semiconductor laser elements are mounted is supported by a support member 42 made of a metal material having high thermal conductivity, such as aluminum. A lens 44 for collimating the laser light emitted from each semiconductor laser element is attached to the surface of the support member 42. Further, a reflection mirror 46 is disposed on the side facing the support member 42, and the reflection mirror 46 reflects blue band light emitted from each semiconductor laser element in a certain direction to generate a laser beam bundle Lb. The configuration in FIG. 2 is an example, and the array light source 40 may have another configuration.

  The first mirror M1 is a dichroic mirror that reflects light in the blue band and transmits light in the other bands. The first mirror M1 is disposed between the first lens L1 and the second mirror M2, and receives blue band light Lb from the array light source 40 as shown in FIG. Reflected toward L1. In the example of the figure, the first mirror M1 is shown inclined at 45 degrees, but it does not necessarily have to be inclined at 45 degrees.

  The first lens L1 condenses the laser beam bundle Lb from the array light source 40 on the first scanning region F1 of the phosphor wheel 20. The first lens L1 may be an optical system capable of condensing the laser beam bundle Lb from the array light source 40, and the number of lenses constituting the first lens L1 may be one. There may be more than one. Although a plano-convex lens is shown in the figure, the first lens L1 may be either a spherical lens or an aspheric lens. The second lens L2 condenses the light reflected by the third mirror M3 in the second scanning region F2 of the phosphor wheel 20. The second lens L2 may be an optical system that can collect incident light in the second scanning region F2, and even if the number of lenses constituting the second lens L2 is one. There may be more than one. Although a plano-convex lens is shown in the figure, the second lens L2 may be either a spherical lens or an aspheric lens.

  It should be noted here that a shift optical system in which the optical axis of the laser beam Lb in the blue band is offset (separated) from the optical axis C1 of the first lens L1 is formed. In the example of FIG. 1, the center of the first mirror M1 or the optical axis C0 of the light beam Lb does not coincide with the optical axis L1 of the first lens L1, and is offset or shifted therefrom. For this reason, all or most of the light flux Lb in the blue band reflected by the first mirror M1 is incident on one half of the optical axis C1 of the first lens L1 (in the example shown in FIG. It is incident on the left side of the lens L1). In the preferred embodiment, the light flux Lb in the blue band reflected by the first mirror M1 does not overlap the optical axis C1 of the first lens L1, but only a part of the light flux Lb in the blue band is on the optical axis C1. It may overlap.

  The phosphor wheel 20 is a disk-shaped rotating body that is rotated by a rotary drive unit 30 including a motor and the like, and is a reflective region that reflects light in the blue band in the circumferential direction of the first radius (r1). And a phosphor region that emits a fluorescent color excited by laser light in a blue band. Further, the phosphor wheel 20 includes a transmission filter region for selectively filtering the light in the blue band and the fluorescent color emitted by the phosphor region in the circumferential direction of the second radius (r2 <r1). It is out. The transmission filter region selectively transmits a specific wavelength from among the wavelengths of light emitted when scanning the circumferential direction of the first radius, improves color rendering, and other wavelengths are mixed. To prevent.

  FIG. 3 shows a specific configuration of the phosphor wheel of this example. 3A is a plan view of the phosphor wheel, and FIG. 3B is a sectional view taken along the line XX. The phosphor wheel 20 includes, in the circumferential direction of the first radius r1, a blue reflecting region 22B that reflects blue band light, a red phosphor region 22R that emits a red band fluorescent color when excited by the blue band light, A green phosphor region 22G that emits a green color fluorescent light when excited by blue band light and a yellow phosphor region 22Y that emits a yellow color fluorescent light when excited by blue light are configured. In addition, a blue transmission filter 24B that selectively transmits the wavelength of the blue band and a red transmission filter that selectively transmits the wavelength of the red band in the circumferential direction of the second radius r2 inside the first radius r1. 24R, a green transmission filter 24G that selectively transmits wavelengths in the green band, and a yellow transmission filter 24Y that selectively transmits wavelengths in the yellow band.

  In the example shown in FIG. 3, the interior angles of the blue reflection region 22B, the red phosphor region 22R, the green phosphor region 22G, and the yellow phosphor region 22Y are 90 degrees, respectively, and the blue transmission filter 24B and the red transmission filter 24R. The internal angles of the green transmission filter 24G and the yellow transmission filter 24Y are each 90 degrees. Then, the blue transmission filter 24B is located on the opposite side of the blue reflection region 22B, that is, the position where the blue reflection region 22B is rotated 180 degrees, and similarly, the red transmission filter 24R is located on the opposite side of the red phosphor region 22R. The green transmission filter 24G is positioned on the opposite side of the green phosphor region 22G, and the yellow transmission filter 24Y is positioned on the opposite side of the yellow phosphor region 22Y.

  As shown in FIG. 3B, the phosphor wheel 20 includes a base 26 made of glass, resin, or metal, and a reflective layer 27 is formed in the circumferential direction of the first radius r1, A phosphor layer 28 is formed thereon. In a preferred embodiment, the reflective layer 27 is formed by a dichroic coat that reflects light having a wavelength other than the blue band. When the phosphor layer 28 is irradiated with the laser beam Lb in the blue band, the R, G, and Y light that has been fluorescently developed spreads in all directions. Therefore, by forming the reflective layer 27 in the lower layer, the phosphor R, G, and Y light are efficiently extracted from the surface side of the wheel 20. Further, the conversion efficiency of the laser beam bundle Lb in the blue band is not 100%, that is, a part of the laser beam bundle Lb in the blue band is not used for fluorescent color development, and therefore the blue band light is absorbed by the reflection layer 27. As a result, the blue band light that has not been used for wavelength conversion is prevented from being mixed with the R, G, and Y fluorescent colors.

  In the case of the blue reflective region 22 </ b> B, when the base material 26 is made of glass or resin, a reflective layer 27 that reflects light in the blue band is formed on the base material 26. When the base material 26 is made of metal, the reflective layer 27 is not necessarily required by making the metal surface a mirror surface. It should be noted that the reflective layer 27 and the phosphor layer 28 shown in FIG. 3B are exaggerated in thickness.

The phosphor layer 28 is configured using a known material. Known phosphor materials that emit fluorescence in the red band include, for example, CaAlSiN ₃ : Eu ²⁺ , Sr ₂ Si ₅ N ₈ : Eu ²⁺ , and SrAlSi ₄ N ₇ : Eu ²⁺ . In addition, as phosphor materials emitting fluorescence in the green band and yellow band, for example, YAG (yttrium, aluminum, garnet), TAG (terbium, aluminum, garnet), sialon, BOS (barium, orthosilicate), Nitride compound systems are known. For example, the phosphor layer 28 may be a mixture of a phosphor material, a resin material, or a ceramic material, or may be a sheet-like material that is a mixture of phosphor materials.

  Further, as shown in FIG. 3B, a blue transmission filter 24B, a red transmission filter 24R, a green transmission filter 24G, and a yellow transmission filter 24Y are provided in the region of the second radius r2 inside the phosphor layer 28. A transmissive filter region 29 for forming is formed. In a preferred embodiment, when the substrate 26 is made of glass, a dichroic coat for selecting B, R, G, and Y wavelength bands is applied to the glass surface. Alternatively, the glass itself may be an optical filter that selects B, R, G, and Y wavelengths. For example, the blue transmission filter 24B highly transmits a wavelength band of about 500 nm or less and highly reflects a wavelength band larger than that. For example, the red transmission filter 24R highly transmits a wavelength band of about 580 nm or more and highly reflects a wavelength band smaller than that. For example, the green transmission filter 24G highly transmits a wavelength band between about 480 nm and about 600 nm, and highly reflects other wavelengths. For example, the yellow transmission filter 24Y highly transmits a wavelength band of about 480 nm or more and highly reflects wavelengths smaller than that. Further, the yellow transmission filter 24Y may be replaced with a red transmission filter 24R or a green transmission filter 24G.

  As a more preferable embodiment, the blue transmission filter 24B includes a diffusion plate or a diffusion layer 29a in order to suppress speckle of the laser light in the blue band. For example, the blue band light may be diffused by forming irregularities on the surface of the blue transmission filter 24B.

  As a more preferable aspect, the phosphor wheel 20 may be configured such that a heat dissipating member 25 is formed on the back surface as shown in FIG. The heat radiating member 25 is made of a material having high thermal conductivity, for example, a metal such as aluminum, iron, or copper, and can be attached to the phosphor wheel 20 with an adhesive having excellent thermal conductivity. The heat radiating member 25 is preferably formed in an annular shape so as to correspond to the position of the phosphor layer 28, but may have other shapes. The phosphor layer 28 generates heat when irradiated with the laser beam Lb in the blue band as excitation light, and the light emission conversion light quantity decreases as the temperature increases. By forming the heat dissipating member 25, the temperature rise of the phosphor layer 28 is suppressed, and the light emission conversion light quantity can be prevented from decreasing.

  The first lens L1 condenses the laser light Lb in the blue band at the scanning position F1 in the vicinity of the first radius r1 of the phosphor wheel 20, and thereby the first radius r1 of the phosphor wheel 20 is increased. The area is optically scanned in the circumferential direction. In addition, as will be described later, the second lens L2 condenses at the scanning position F2 in the vicinity of the second radius r2 of the phosphor wheel 20, and thereby the region of the second radius r2 of the phosphor wheel 20 Are optically scanned in the circumferential direction.

  In the above example, the phosphor wheel 20 is formed with the phosphor layer 28 for emitting light in the red band, the green band, and the green band. When it is desired to obtain light, the phosphor layer may include a red phosphor region and a green phosphor region, and, of course, a phosphor region that is a combination of other fluorescent colors is formed. You may do it. Furthermore, in the above example, an example is shown in which the inner angles of the blue reflection region 22B, the red phosphor region 22R, the green phosphor region 22G, and the yellow band phosphor region 22Y are 90 degrees. It is possible to appropriately change the brightness according to the brightness and other design matters. In this case, for example, if the internal angle of the blue reflection region 22 is 60 degrees, the internal angle of the blue transmission filter 24B is also set to 60 degrees, and similarly, if the internal angle of the red phosphor region 22R is 120 degrees. Correspondingly, the inner angle of the red transmission filter 22R is also set to 120 degrees.

  FIG. 4A shows a state in which the blue reflection region 22B of the phosphor wheel 20 is irradiated with the laser light in the blue band. The light flux Lb in the blue band reflected by the first mirror M1 is incident on one half of the first lens L1, and scans the scanning region F1 of the phosphor wheel 20. While the light beam Lb scans the blue reflection region 22B, the light beam Lb is regularly reflected by the blue reflection region 22B. That is, the incident angle θ1 and the reflection angle θ2 of the light beam Lb with respect to the blue reflection region 22B are substantially equal. Accordingly, the light beam Lb ′ regularly reflected by the blue reflection region 22B is emitted from the opposite side of the optical axis C1 of the first lens L1, and is condensed into substantially parallel light.

  FIG. 4B shows a state when the red phosphor region 22R, the green phosphor region 22G, and the yellow phosphor region 22Y of the phosphor wheel 20 are scanned. When the light beam Lb in the blue band irradiates the red phosphor region 22R, the light in the red band excited by the light beam Lb fluoresces. The fluorescently colored red band light is emitted from the surface of the phosphor wheel 20 in a Lambertian shape (uniform diffusion). The red band light Lr emitted in a Lambertian shape is condensed into a substantially parallel light bundle by the first lens L1. Similarly, when the green phosphor region 22G and the yellow phosphor region 22Y are irradiated with the laser beam of the blue band, the green color light Lg and the yellow band light Ly that are fluorescently emitted are emitted in a Lambertian shape.

  Refer to FIG. 1 again. The second mirror M2 is configured by, for example, a total reflection mirror so as to reflect light in the R, G, B, and Y wavelength bands, and is inclined at approximately 45 degrees with respect to the optical axis C1. The third mirror M3 is also composed of, for example, a total reflection mirror so as to reflect light in the R, G, B, and Y wavelength bands, and is inclined at approximately 135 degrees with respect to the optical axis C1. Thus, the light flux Lb in the blue band emitted from the phosphor wheel 20 is emitted from the opposite side of the optical axis C1 of the first lens L1 toward the second mirror M2, and the second and third mirrors M2 , M3, and reflected at right angles, again incident on one side of the optical axis C2 of the second lens L2, and condensed on the second scanning region F2 of the phosphor wheel 20. The R, G, and Y light emitted from the phosphor wheel 20 is transmitted through the first dichroic mirror M1, reflected at right angles by the second and third mirrors M2 and M3, and the second lens L2. Thus, the light is condensed on the second scanning region F2 of the phosphor wheel 20.

  As shown in FIG. 3A, the first scanning region F1 is a region in the circumferential direction with the first radius r1, and the second scanning region F2 is in the circumferential direction with the second radius r2. It is an area. Further, the scanning region F2 and the scanning region F1 have an angular difference of 180 degrees with respect to the center O. Accordingly, the B light output during the scanning of the blue reflection region 22B is incident on the blue transmission filter 24B, and the R light output during the scanning of the red phosphor region 22R is incident on the red transmission filter 24R. The G light output during scanning of the green fluorescent region 22G is incident on the green transmission filter 24G, and the Y light output during scanning of the yellow fluorescent region 22Y is incident on the yellow transmission filter 24Y. The R, G, and Y light generated when the phosphor region is scanned may include blue band light that is excitation light that has not been used for fluorescent color development. Since light does not pass through the transmission filter regions 24R, 24G, and 24Y, it is possible to prevent B light from being mixed with R, G, and Y light.

  A light tunnel LT (or an optical integrator) arranged close to the second scanning region F2 of the phosphor hole 20 receives B, R, G, and Y light continuously output from the phosphor wheel 20. This is supplied to a light modulation device such as a digital mirror device (DMD). The DMD modulates R, G, B, and Y light in accordance with the digital image data to generate a projection image.

  Next, another configuration example of the phosphor wheel of this embodiment will be described. FIG. 5 shows another configuration example of the phosphor wheel. The phosphor wheel 20A is obtained by removing the yellow phosphor region 22Y and the yellow transmission filter region 24Y from the phosphor wheel 20 shown in FIG. 3, and the other configurations are the same. That is, a blue reflection region 22B, a red phosphor region 22R, and a green phosphor region 22G are formed in the circumferential direction of the first radius, and a blue transmission filter region 24B and a red transmission region are formed in the circumferential direction of the second radius. A filter region 24R and a green transmission filter region 24G are formed. Then, R, G, and B light is output from the back side of the phosphor wheel 20A.

  FIG. 6 is a plan view showing a configuration of another phosphor wheel of the present embodiment. In the phosphor wheel 20 shown in FIG. 3, the region formed in the circumferential direction of the first radius and the corresponding region formed in the circumferential direction of the second radius are in a relationship of 180 degrees with respect to the center O. In the phosphor wheel 20B shown in FIG. 6, the region formed in the circumferential direction of the first radial direction and the region formed in the circumferential direction of the second radius are 180. Arranged with a certain angular difference smaller than degrees. In other words, in the illumination optical system 10 shown in FIG. 1, the first and second lenses L1, L2 is installed, but when the phosphor wheel 20B of this example is used, the first and second scanning regions F1 and F2 do not need to be at both ends. The two lenses L1 and L2 can be arranged close to each other. As shown in FIG. 6, when the first scanning region F1 is at an angle α from the boundary between the blue reflection region 22B and the red phosphor region 22R, the second scanning region F2 is connected to the blue transmission filter region 24B and the red transmission region. Each region in the circumferential direction of the first radius and each region in the circumferential direction of the second radius are arranged so that the angle relationship is satisfied from the boundary of the filter region 24R and α = β is satisfied. Just do it. Such an illumination optical system can save space compared to the illumination optical system of FIG.

  The phosphor wheel 20C shown in FIG. 7 has the same configuration in the circumferential direction of the first radius as the phosphor wheel 20 shown in FIG. 3, but the configuration in the circumferential direction in the second radial direction is different. ing. That is, the blue transmission filter region 24B and the blue reflection region 24BR are formed in the circumferential direction of the second radius. The blue reflection region 24BR replaces the R, G, and Y transmission filter regions 24R, 24G, and 24Y. The blue reflective region 24BR is formed, for example, by applying dichroic coating that transmits light other than blue in the circumferential direction of the second radius. During the scanning period of the red phosphor region 22R, the green phosphor region 22G, and the yellow phosphor region 22Y, the blue reflecting region 24BR reflects unconverted blue light contained in R, G, and Y, and Transmits light. This prevents R, G, and Y from mixing blue light.

  FIG. 8 is a diagram illustrating a configuration example of another phosphor wheel according to the present embodiment. In this example, the phosphor wheel 20D and the first and second lenses L1 and L2 can relatively move in the horizontal direction H. The moving means is configured using a known technique. As shown in FIG. 8A, when the phosphor wheel 20D is in the first position, the first lens L1 scans the first scanning region F1A, and the second lens L2 The scanning area F2A is scanned. Further, as shown in FIG. 8B, when the phosphor wheel 20D is moved to the second position, the first lens L1 scans the first scanning region F1B, and the second lens L2 The second scanning region F2B is scanned. The phosphor wheel 20D shown in FIG. 8C is obtained by synthesizing the phosphor wheel 20B shown in FIG. 6 and the phosphor wheel 20C shown in FIG. 7, and when the phosphor hole 20D is in the first position. When the configuration of the phosphor wheel 20C shown in FIG. 7 is selected (F1A and F2A are scanned) and is in the second position, the configuration of the phosphor wheel 20B shown in FIG. 6 is selected (F1B and F2B). Is scanned). This makes it possible to select one of the two light output modes from the single phosphor hole 20D.

  Next, a configuration example of another phosphor wheel of the present embodiment is shown in FIG. The phosphor wheel 20E shown in the figure has two base materials 26A and 26B coupled on the same axis of the rotation drive unit 30. The first base material 26A is made of a material having a good thermal conductivity, for example, a metal, and the phosphor layer 28 and the blue reflective region are formed on the first base material 26A via the reflective layer 27. The second base material 26B is made of a transparent material such as glass or resin, and an optical filter is coated on the surface of the transparent base material. The blue transmission filter region 24B, the red transmission filter region 24R, and the green transmission filter region. 24G and a yellow transmission filter region 24Y are formed. In this example, the first base material 26A corresponds to the first scanning region F1, the second base material 26B corresponds to the second scanning region F2, and the laser beam in the blue band by the first lens L1. Condensation of the bundle Lb is performed on the first base material 26A, and condensing by the second lens L2 is performed on the second base material 26B.

  As the characteristics of the phosphor, a linear region where the light emission conversion efficiency increases as the light irradiation energy density and temperature increase (conversion efficiency is constant), a saturation region where the light emission conversion amount is saturated (conversion efficiency decreases), It is known to have a degradation region in which the amount of luminescence conversion degrades. For this reason, when the phosphor is 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. By using the phosphor wheel 20E as shown in FIG. 9, the heat dissipation characteristics of the first base material 26A can be improved, the phosphor can be prevented from thermal damage, and the deterioration of the light emission conversion amount can be prevented.

  FIG. 10 shows a configuration example of another phosphor wheel of this example. The phosphor hole 20F shown in the figure includes a blue reflection region 22B and a yellow phosphor region 22Y in the circumferential direction of the first radius. Preferably, the area of the yellow phosphor region 22Y is set larger than that of the blue reflection region 22B, that is, the scanning period of the yellow phosphor region 22Y is set longer. In this example, red and green phosphors are not used, but yellow phosphors are used. This is because the phosphor that develops yellow color has higher conversion efficiency and can increase the amount of emitted light than the phosphor that develops red and green.

  In the circumferential direction of the second radius of the phosphor wheel 20F, a blue transmission filter region 24B is formed corresponding to the blue reflection region 22B, and a red transmission filter region 24R corresponding to the yellow phosphor region 22Y and A green transmission filter region 24G is formed. Since the light colored in the yellow phosphor region 22Y includes wavelengths in the red band and the green band, the red transmission filter region 24R selectively transmits light in the red band from among the red transmission filter region 24G and the green transmission filter region 24G. Selectively transmits light in the green band. Note that the ratio of the size of the red transmission filter region 24R and the size of the green transmission filter region 24G can be set as appropriate, but by increasing the ratio of the red transmission filter region 24R relatively, the output of light in the red band can be increased. It is possible to generate an image having a color rendering property of red.

  Next, FIG. 11 shows an illumination optical system according to the second embodiment of the present invention. In the illumination optical system 10A of the second embodiment, the laser beam Lb in the blue band is incident on the first mirror M1 from the opposite direction to the illumination optical system 10 in FIG. Other configurations are the same as those in FIG.

  Next, an illumination optical system according to a third embodiment of the present invention is shown in FIG. In the illumination optical system 10B of the third example, the laser beam Lb in the blue band is incident via the second mirror M2 from the direction parallel to the optical axis C1 of the first lens L1. In this case, the second mirror M2 is composed of a dichroic mirror that transmits light in the blue band and reflects other light. The optical axis C0 or the center of the light flux Lb in the blue band constitutes a shift optical system that is offset from the optical axis C1 of the first lens L1, and the light flux Lb in the blue band is the same as that of the first lens L1. The light enters from one side and exits from the opposite side. Further, in the third embodiment, the first mirror M1 is not necessary, but the fourth mirror M4 is disposed adjacent to the rear of the third mirror M3. The fourth mirror M4 reflects the light flux Lb in the blue band transmitted through the second dichroic mirror M2 toward the third mirror M3.

  Next, FIG. 13 shows an illumination optical system according to the fourth embodiment of the present invention. The illumination optical system 10C of the fourth embodiment reflects a third lens that collects a laser beam bundle Lb in a blue band from an array light source (not shown) and a light bundle Lb emitted from the third lens L3. A first dichroic mirror M1 is included. The optical axis C0 of the light beam Lb reflected by the first mirror M1 constitutes a shift optical system that is offset from the optical axis of the first lens L1, as in FIG. The light flux Lb in the blue band emitted from the phosphor wheel 20 passes through the second dichroic mirror M2, and is reflected toward the third mirror M3 by the fourth mirror M4. In the illumination optical system 10C of this example, by adjusting the position of the fourth mirror M4, the laser beam Lb in the blue band is condensed near the optical axis of the second lens L2, and the beam bundle in the blue band is collected. The uniformity of Lb can be improved. Other configurations are the same as those in FIG.

  Next, FIG. 14 shows an illumination optical system according to the fifth embodiment of the present invention. The illumination optical system 10D of the fifth embodiment divides the phosphor wheel used in the illumination optical system of FIG. 1 into two, and the first and second phosphor wheels 20-1 and 20-2 are orthogonal to each other. The first and second phosphor wheels 20-1 and 20-2 are rotated in synchronization with each other. The first phosphor wheel 20-1 has a blue reflection region 22B, a red phosphor region 22R, a green phosphor region 22G, and a yellow phosphor region 22Y, which serve as a first scanning region in the circumferential direction with a first radius. It is comprised including. The light reflected at right angles by the second mirror M2 is condensed on the second scanning region F2 of the second phosphor wheel 20-2 by the second lens L2. In the second scanning region F2, a blue transmission filter region 24B, a red transmission filter region 24R, a green transmission filter region 24G, and a yellow transmission filter region 24Y are formed. In this example, the second phosphor wheel 20-2 is added, but the third mirror M3 is unnecessary.

  Next, FIG. 15 shows an illumination optical system according to the sixth embodiment of the present invention. The illumination optical system 10E of the sixth example is a modification of the fifth example. As shown in the figure, the first and second phosphor wheels 20-1 and 20-2 are arranged in parallel, and the first and second phosphor wheels 20-1 and 20-2 are arranged in parallel. It is rotated synchronously. In the illumination optical system 10E of this example, the optical axis C1 of the first lens L1 and the optical axis L2 of the second lens L2 are parallel, and the light from the first lens L1 is transmitted by the second lens l2. The light is condensed on the second scanning region F2 of the second phosphor wheel 20-2. Compared with the illumination optical system 10D of the fifth embodiment shown in FIG. 14, the second mirror M2 is not required, so that the space of the illumination optical system 10E can be saved. The first and second phosphor wheels 20-1 and 20-2 may be configured such that both rotation axes are connected.

  In the above embodiment, the diffusion layer 29a is formed on the surface of the blue transmission region 24B of the phosphor wheel 20. However, a diffusion member for suppressing speckles on the optical path of the laser beam Lb in the blue band is shown. It may be arranged. Furthermore, the size of the phosphor region formed on the phosphor wheel, the color of the fluorescent color, and the like can be appropriately changed according to the purpose.

  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, 10D, 10E: illumination optical system 20, 20A, 20B, 20C, 20D, 20E, 20F: phosphor wheel 22B: blue reflection region 22R: red phosphor region 22G: green phosphor region 22Y : Yellow phosphor region 24B: Blue transmission filter region 24R: Red transmission filter region 24G: Green transmission filter region 24Y: Yellow transmission filter regions 26, 26A, 26B: Base material 27: Reflective layer 28: Phosphor layer 29: Transmission filter Area 29A: Diffuse surface 30: Rotation drive unit 40: Array light source L1: First lens L2: Second lens M1: First mirror M2: Second mirror M3: Third mirror M4: Fourth mirror LT: light tunnel F1: first scanning region F2: second scanning region

Claims (5)

A light source that emits light in a first wavelength band;
The light of the first wavelength band emitted from the light source is incident, and the reflection region for reflecting the light of the first wavelength band and the light of the second wavelength band excited by the first wavelength band are generated. First generation means including a phosphor region;
A first transmission region for transmitting light in the first wavelength band and light in the first wavelength band and light in the second wavelength band generated by the first generation means; Second generation means including a second transmission region that transmits light,
First generating means may have a light axis that is shifted from the optical axis of the principal ray of the first wavelength band, the first generation means comprises a lens, one half of the light of the first wavelength band lens The light of the first wavelength band that is incident only from and reflected by the reflection region is emitted only from the opposite half of the lens,
The rotating members of the first generating unit and the second generating unit are the same rotating member, and the first generating unit includes at least the reflection region and the phosphor region in the circumferential direction of the first radius. An illumination optical system in which the second generation means forms at least the first transmission region and the second transmission region in the circumferential direction of the second radius . The first generation means includes a dichroic mirror that reflects light from the light source toward the lens, and the dichroic mirror reflects light in a first wavelength band and is generated in the phosphor region. The illumination optical system according to claim 1, which transmits light in two wavelength bands. The illumination optical system according to claim 1, wherein the first generation unit includes a rotating member in which at least the reflection region and the phosphor region are formed in a circumferential direction. The illumination optical system according to any one of claims 1 to 3, wherein the second generation unit includes a rotating member in which at least the first transmission region and the second transmission region are formed in a circumferential direction. . An electronic device comprising the illumination optical system according to claim 1.

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