Light source device and projection device

Abstract

To provide a light source device that can be reduced in size and can reduce luminance unevenness and color unevenness, and a projection device.SOLUTION: The present invention comprises: a light source unit that includes an arrangement area where a plurality of light sources are arranged, in which the arrangement area is divided into division areas each including one or more light sources and the division directions of the division areas in the arrangement area are substantially aligned; and an optical system that forms a first image of the light source unit. The present invention causes the optical system to pass light beams emitted from the light sources in the vicinity of an optical axis of the optical system on an image surface on which the first image is formed, and to change optical output from the light sources included in the division areas.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a light source device and a projection device.

Background Art

[0002] Today, projectors (an example of a projection device) that enlarge and project various images are widely popular. A projector condenses light emitted from a light source onto a spatial light modulation element such as a digital micromirror device (DMD) or a liquid crystal display element, and displays the emitted light from the spatial light modulation element modulated by a video signal as a color image on a screen.

[0003] Conventionally, high-intensity ultra-high pressure mercury lamps etc. have mainly been used for projectors, but due to their short lifespan, frequent maintenance has been necessary. To solve these problems, in recent years, the number of projectors using lasers or LEDs (Light Emitting Diodes) instead of ultra-high pressure mercury lamps has been increasing. This is because lasers have a longer lifespan compared to ultra-high pressure mercury lamps, and also have good color reproducibility due to their monochromaticity.

[0004] In a projector, an image is formed by irradiating a spatial light modulation element such as the above-mentioned DMD with three colors: red, green, and blue. Although all three of these colors can be generated by a laser light source, the luminous efficiency of green lasers and red lasers is lower than that of blue lasers. For this reason, a general method is to irradiate a phosphor with blue laser light as excitation light, and generate green and red light from the fluorescent light wavelength-converted by the phosphor. Also, as a method using a laser light source, a method has been developed in which laser elements are arranged on a matrix to increase the amount of light.

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, as a method for reducing brightness unevenness and color unevenness, a method of lengthening the light tunnel can be considered, but the light source and the projector become larger in size.

[0006] The present invention has been made in view of the above, and an object thereof is to provide a light source device and a projection device that can be miniaturized and can reduce luminance unevenness and color unevenness.

Means for Solving the Problems

[0007] In order to solve the above-described problems and achieve the object, the present invention arranges a plurality of light sources Shi including an arrangement region, the arrangement region being divided into divided regions each including one or more of the light sources, and the division directions of the divided regions in the arrangement region being substantially aligned, a light source unit, an optical system that forms a first image of the light source unit, and a light homogenizing element having an aperture into which a light beam emitted from the optical system is incident in the vicinity of an image plane on which the first image is formed, the aperture being a substantially rectangular aperture having a long side and a short side in a cross section perpendicular to the traveling direction of the incident light beam, and the optical system passing the light beam emitted from the light source through the vicinity of the optical axis of the optical system on the image plane on which the first image is formed and guiding the light beam to irradiate the side surface of the long side of the aperture surface of the light homogenizing element across the optical axis, The arrangement area is rectangular, the division direction is a direction corresponding to the long side direction in the opening, and in the division direction changing the light output of the light sources included in each of the divided regions so that they are different from each other

Effects of the Invention

[0008] According to the present invention, there is an effect that it is possible to miniaturize and reduce luminance unevenness and color unevenness.

Brief Description of the Drawings

[0009]

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BEST MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, embodiments of the light source device and the projection device will be described in detail with reference to the accompanying drawings.

[0011] (First Embodiment) FIG. 1 is a diagram for explaining an outline of the features of a projector according to the first embodiment. First, with reference to FIG. 1, an outline of the features of the projector according to the present embodiment will be described. The projector (an example of a projection device) according to the present embodiment reduces luminance unevenness and color unevenness of a projected image (hereinafter referred to as a screen projected image) projected onto a screen. Specifically, as shown in FIG. 1, when the projector according to the present embodiment projects a screen projected image having a short side in the vertical direction onto the screen, the optical system (light source device or light source optical system) reduces luminance unevenness and color unevenness in the vertical and horizontal directions of the screen projected image, and controls the LD output (an example of the light output) of the LD light source (an example of the light source unit) (hereinafter referred to as LD control) to mainly reduce luminance unevenness and color unevenness in the horizontal direction of the screen projected image.

[0012] The projector according to the present embodiment adjusts the light quantity distribution of the screen projected image by changing the input current value to the LD light source to perform LD control, thereby reducing luminance unevenness and color unevenness of the screen projected image. However, for example, instead of changing the LD output of the LD light source, the light quantity passing through the liquid crystal or shutter may be adjusted by narrowing it, or both may be used.

[0013] According to the projector according to the present embodiment, luminance unevenness and color unevenness of the screen projected image that cannot be eliminated only by the light source optical system can be reduced by LD control. Further, according to the projector according to the present embodiment, when projecting a screen projected image having a long side in the vertical direction, the light source optical system can reduce luminance unevenness and color unevenness in the horizontal and vertical directions of the screen projected image, and LD control can mainly reduce luminance unevenness and color unevenness in the vertical direction.

[0014] FIG. 2 is a diagram for explaining an example of the relationship between a part of the light source optical system of the projector according to the first embodiment and an image of the light source. Next, with reference to FIG. 2, an outline of the optical system included in the projector according to the present embodiment will be described. In the following description, the lens center axis connecting the lens centers of the second optical system 205 and the condenser lens 207 is defined as the optical axis.

[0015] The LD light source light excited (emitted) from the LD light source Md is reflected by the dichroic mirror 204, condensed by the second optical system 205, and imaged as a second image, which is a conjugate image of the LD light source Md, on the light source image plane X1 (represented by a dotted line) on the phosphor wheel 206. Here, the phosphor wheel 206 functions as an example of a wavelength conversion unit that emits wavelength-converted light (fluorescent light) obtained by converting the wavelength of the LD light source light (excitation light) emitted from the LD light source Md. Further, the phosphor wheel 206 is disposed near the light source image plane X1. Also, it is assumed that the conjugate position of the wavelength-converted light emitted from the phosphor wheel 206 and the conjugate position of the LD light source light emitted from the LD light source Md substantially coincide. That is, the second optical system 205 and the condenser lens 207 form an image of the wavelength-converted light conjugate to the light source image formed on the phosphor wheel 206 near the conjugate image plane X2. The LD light source light is reflected by the mirror surface of the phosphor wheel 206, refracted by the second optical system 205, and then refracted by the condenser lens 207, and imaged as a first image, which is a conjugate image of the LD light source Md, on the conjugate image plane X2 (represented by a dotted line). In FIG. 2, the dotted line representing the conjugate image plane X2 and the opening surface of the light tunnel LT are drawn with a gap therebetween, but in actuality, it is assumed that they substantially coincide. In the present embodiment, the second optical system 205 and the condenser lens 207 function as an example of an optical system having an optical axis on which a conjugate image of the LD light source Md is formed. That is, the second optical system 205 and the condenser lens 207 form a first image conjugate to the LD light source Md on the optical path of the light beam of the LD light source light between the laser light source 201 (see FIG. 4) of the LD light source Md and the conjugate image plane X2. Then, the second optical system 205 and the condenser lens 207 guide the light beam of the LD light source light emitted from the LD light source Md so that the light beam passes through the optical axis of the optical system (the second optical system 205 and the condenser lens 207) at the conjugate image plane X2 where the first image is formed. Specifically, the LD light source light emitted from the LD light source Md is guided so as to pass through the optical axis at a substantially conjugate position (conjugate image plane X2) when viewed from the short side direction of the first image. In other words, the LD light source light emitted from the LD light source Md is at an angle θ with respect to the short side direction (corresponding to the Z axis) of the first image S (0 < θ S(<90°), and proceeds at approximately 0° with respect to the long side direction (corresponding to the Y-axis) of the first image. Also, the light tunnel LT is arranged near the position of the conjugate image plane X2 where the first image is formed, and functions as an example of a light homogenizing element having an aperture into which the light beam emitted from the second optical system 205 and the condenser lens 207 is incident. In the present embodiment, the light tunnel LT is a light tunnel having a substantially rectangular aperture in a cross section perpendicular to the traveling direction of the light beam of the LD light source light emitted from the LD light source Md (in the cross-sectional direction orthogonal to the traveling direction).

[0016] Since the first image and the second image are images obtained by reducing the LD light source light emitted from the LD light source Md, the light source device 102 can efficiently capture the LD light source light with respect to the light homogenizing element, for example, by adjusting the vertical and horizontal sizes of the first image to be less than or equal to the short side distance SE and the long side distance LE of the aperture size of the light homogenizing element (light tunnel LT).

[0017] Note that the LD light source light is refracted by the condenser lens 207 by θ in the Z-axis direction S (0° ≤ θ S ), and by θ in the Y-axis direction L (0° ≤ θ L ). For example, θ S is desirably about 5 to 60°. Also, θ L is desirably about 3 to 5°, and of course, 0° is also possible. However, θ S and θ LNeither of them will become 0°, and at least one of them will be greater than 0°. In the present embodiment, the fact that the LD light source light refracted by the condenser lens 207 travels in the optical axis direction (in other words, the light beam of the LD light source light passes near the optical axis of the optical system (condenser lens 207) at the conjugate image plane X2 by the condenser lens 207) is defined as "crossing the optical axis". Specifically, "crossing the optical axis" means that, from the viewpoint in the optical axis direction of the optical system, after the light beam of the LD light source light travels from the outer peripheral portion of the condenser lens 207 toward the optical axis and then moves away from the optical axis of the LD light source light (including the case where the center of the LD light source light does not intersect the optical axis). Also, in the present embodiment, the "vicinity" in "near the optical axis" means that after the LD light source light crosses the optical axis, it is at a distance of the short side of the opening surface of the light tunnel LT / tan(θ S ) or less or the long side / tan(θ L ) or less in the X-axis direction.

[0018] FIG. 3 is a schematic configuration diagram showing an example of a projector according to the first embodiment. Next, the schematic configuration of the projector 101 according to the present embodiment will be described with reference to FIG. 3. The projector 101 according to the present embodiment homogenizes the LD light source light emitted from the light source device 102 by mixing it with a light tunnel LT (an example of a light homogenizing element). Next, the projector 101 irradiates the image forming element 105 with the LD light source light homogenized by the light tunnel LT substantially uniformly using the illumination optical system 104, and enlarges and projects (forms an image) the image (screen projection image) formed by the image forming element 105 onto the screen SC by the projection optical system 106. The image forming element 105 functions as an example of an image forming element disposed at a position (conjugate position) where an image of the light emitting portion (opening) that emits light from the light tunnel LT is formed. Here, in FIG. 3, a configuration example of the projector 101 using a DMD is shown, but it is not limited thereto. The specific configuration of the light source device 102 will be described in detail later.

[0019] Here, as the light homogenizing element, a light tunnel combining four mirrors, a rod integrator, a fly-eye lens, or the like is used. Further, as the image forming element 105, for example, a light valve such as a DMD, a transmissive liquid crystal panel, or a reflective liquid crystal panel is used. Specific examples of the illumination optical system 104 and the projection optical system 106 are omitted here.

[0020] The meanings of various symbols in this embodiment are as follows. f: Focal length of the entire system R: Radius of curvature (in the case of an aspherical surface, the paraxial radius of curvature) D: Spacing between surfaces Nd: Refractive index vd: Abbe number K: Conic constant of the aspherical surface Ai: Aspherical coefficient of the i-th order The aspherical shape is represented by a well-known formula using the reciprocal of the paraxial radius of curvature (paraxial curvature): C, the height from the optical axis: H, the conic constant: K, and the aspherical coefficients of the above respective orders, with X being the aspherical amount in the optical axis direction, and the shape is specified by giving the paraxial radius of curvature, the conic constant, and the aspherical coefficients.

[0021] FIG. 4 is a schematic configuration diagram of an example of the light source device according to the first embodiment. Next, with reference to FIG. 4, the schematic configuration of the light source device 102 according to this embodiment will be described. In this embodiment, the light source device 102 includes a laser light source 201 which is a solid light source, a collimator lens 202 corresponding to each laser light source 201, a first optical system 203, a dichroic mirror 204, a second optical system (condensing optical system) 205, a phosphor wheel 206, a condensing lens 207, and a color wheel 208. In this embodiment, the light source device 102 is arranged in the propagation direction of the excitation light (LD light source light) emitted from the laser light source 201 in the order of the collimator lens 202, the first optical system 203, the dichroic mirror 204, the second optical system (condensing optical system) 205, the phosphor wheel 206, the condensing lens 207, and the color wheel 208.

[0022] The laser light source 201 (an example of a light source) emits, for example, LD light source light (blue excitation light) in a blue band with a central wavelength of 455 nm as excitation light for exciting the phosphor included in the phosphor wheel 206 described later. The blue excitation light emitted from the laser light source 201 is linearly polarized light with a constant polarization state and is arranged to be S-polarized with respect to the dichroic mirror 204. Also, the wavelength band of the excitation light is not limited to the blue band excitation light as long as it is light with a wavelength capable of exciting the phosphor included in the phosphor wheel 206 described later. Further, although the laser light source 201 is shown by taking as an example the use of a plurality of laser light sources, a single laser light source may also be used. Also, as the plurality of laser light sources, a light source unit arranged in an array on a substrate may be used, but it is not limited thereto. Here, the center line of the light beam formed by the plurality or single laser light source is defined as the principal ray.

[0023] The excitation light emitted from the plurality of laser light sources 201 becomes substantially parallel light by the collimator lens 202 corresponding to each laser light source 201. The excitation light that has become substantially parallel light enters the first optical system 203. The optical axis of the first optical system 203 is arranged to pass through the center of the light source array of the laser light source 201. That is, the principal ray of the excitation light coincides with the optical axis of the first optical system 203. The excitation light that has passed through the first optical system 203 is guided to the dichroic mirror 204 arranged at an angle of 45 degrees with respect to the optical axis of the first optical system 203. Here, in the present embodiment, a configuration in which the dichroic mirror 204 is arranged at an angle of 45 degrees is shown, but other angles may also be used. The dichroic mirror 204 is coated so as to reflect light in the wavelength band of the excitation light and transmit the fluorescence light generated from the phosphor of the phosphor wheel 206 described later. Also, in the present embodiment, a flat dichroic mirror 204 is used, but a prism-type dichroic mirror 204 may also be used. The excitation light reflected by the dichroic mirror 204 has its optical path rotated by 90 degrees and enters the second optical system 205 (condensing optical system). Here, the optical axes of the first optical system 203 and the second optical system 205 (condensing optical system) are substantially eccentric.

[0024] FIG. 5 is a diagram showing an example of the configuration of a first optical system, a reflecting surface, and a second optical system (condensing optical system) included in the projector according to the first embodiment. When a plane including the incident surface (reflecting surface) of the excitation light of the dichroic mirror 204 is defined as a first plane Y1, an intersection point of the first plane Y1 and the optical axis of the first optical system 203 is defined as a point P, and an intersection point of the first plane Y1 and the optical axis of the second optical system 205 (condensing optical system) is defined as a point Q, a maximum distance among distances between the point P and the point Q in a direction within a plane perpendicular to the optical axis of the second optical system 205 (condensing optical system) is defined as ΔL. As a result, the excitation light is incident on the second optical system 205 (condensing optical system) in an eccentric state. Here, as shown in FIG. 5, an outer diameter of an optical element disposed on the incident side of the second optical system 205 (condensing optical system) is defined as D, and a plane including a surface vertex of the optical element on the incident side of the second optical system 205 (condensing optical system) and perpendicular to the optical axis of the second optical system 205 (condensing optical system) is defined as a second plane Y2.

[0025] FIG. 6 is a diagram showing an example of an image of the excitation light projected onto the second plane in the projector according to the first embodiment. Specifically, FIG. 6 is a diagram showing an image of the light beam of the excitation light (first color light) passing through the second plane Y2 projected onto the second plane Y2 in an optical path from the laser light source 201 to the wavelength conversion element (phosphor wheel 206) in the projector 101 according to the first embodiment, and an image of the second plane Y2 projected onto the incident surface side of the second optical system 205 (condensing optical system). Here, the area of the light beam of the first color light represents an area of a portion having an intensity equal to or higher than 1 / e^2 of the peak intensity.

[0026] The excitation light that has passed through the second optical system 205 (condensing optical system) is guided to the phosphor wheel 206. In the present embodiment, the spot diameter of the excitation light guided onto the surface of the phosphor wheel 206 is increased by shifting it from a conjugate surface (light source image plane X1) on the phosphor wheel 206, and the fluorescence conversion efficiency is improved by reducing the amount of heat in the phosphor region of the phosphor wheel 206. Since the excitation light is incident on the second optical system 205 (condensing optical system) eccentrically, the excitation light is incident obliquely on the phosphor wheel 206.

[0027] FIG. 7 is a schematic diagram showing an example of a light beam incident on the phosphor wheel in the projector according to the first embodiment. In the projector 101 according to the present embodiment, the optical axis of the second optical system 205 and the light beam of the excitation light incident on the phosphor wheel 206 form an angle θ.

[0028] FIG. 8 is a diagram showing an example of the configuration of the phosphor wheel included in the projector according to the first embodiment. In the projector 101 according to the present embodiment, the phosphor wheel 206 on the disk is attached to the drive motor 801, and by rotating the phosphor wheel 206 at high speed, the position where the LD light source light is irradiated on the phosphor wheel 206 is moved in time. In the present embodiment, the phosphor of the phosphor wheel 206 is divided into a phosphor region 206a where the phosphor is applied and an excitation light reflection region 206b that reflects the LD light source light. In the present embodiment, an example in which the phosphor wheel 206 is divided into two regions, the phosphor region 206a and the excitation light reflection region 206b, is shown, but the phosphor region 206a may be divided into a plurality of regions, and the excitation light reflection region 206b may be divided into a plurality of regions.

[0029] As the substrate 802 of the phosphor wheel 206, a transparent substrate or a metal substrate such as aluminum can be used, but it is not limited thereto. In the excitation light reflection region 206b, for example, a reflection coat 802a having a high reflectance may be formed on the substrate 802 by the LD light source light, or the substrate 802 itself can be used as the excitation light reflection region 206b by using the substrate 802 as a metal substrate. The phosphor region 206a shows an example in which a reflection coat 206c that reflects light in the wavelength region of the light emitted from the phosphor, a phosphor layer 206d, and a reflection coat 206e (AR coat) that reduces reflection on the phosphor surface are formed, but it is not limited thereto. By using the substrate 802 as a metal, it is also possible to eliminate the reflection coat 206e. As the phosphor layer 206d, a phosphor material dispersed in an organic or inorganic binder or a crystal of the phosphor material directly formed may be used. As the phosphor material, for example, a rare earth phosphor such as a Ce:YAG system can be used, but it is not limited thereto, and a phosphor, a nonlinear optical crystal, or the like may be used. The wavelength band of the light emitted from the phosphor can be, for example, those in the wavelength bands of yellow, blue, green, and red. In the present embodiment, only the case of using fluorescent light having a yellow wavelength band will be described.

[0030] Returning to FIG. 4, since the excitation light reflected by the excitation light reflection region 206b of the phosphor wheel 206 is specularly reflected by the excitation light reflection region 206b, as shown in FIG. 4, it passes through the side opposite to the incident side of the second optical system 205 (condensing optical system) and is emitted from the second optical system 205 (condensing optical system).

[0031] The excitation light emitted from the second optical system 205 (condensing optical system) enters the condenser lens 207 without passing through the dichroic mirror 204, passes through the color wheel 208, and is guided to the light homogenizing element 209 near the position of the conjugate surface (conjugate image plane X2) of the LD light source Md. In this embodiment, a configuration is shown in which the excitation light reflected by the phosphor wheel 206 does not pass through the dichroic mirror 204. However, it is also possible to use a dichroic mirror 204 with a larger size, where the coating on half of the surface has the property of reflecting the excitation light and transmitting the fluorescence light, and the remaining half of the surface has the property of transmitting both the excitation light and the fluorescence light. Also, when the excitation light enters the region coated with the phosphor, the fluorescence light is emitted from the incident surface side of the excitation light and enters the second optical system 205 (condensing optical system). A part of the excitation light that has passed through the second optical system 205 (condensing optical system) passes through the excitation light reflection part of the dichroic mirror 204, enters the condenser lens 207, and is guided to the color wheel 208 and the light tunnel LT. At this time, the conjugate positions of the excitation light and the wavelength-converted light (fluorescence light) with respect to the LD light source Md are substantially coincident.

[0032] The condenser lens 207 is a single optical element, and both surfaces are spherical surfaces that can be rotated. Note that the condenser lens 207 is not limited to spherical surfaces and may be aspherical on one or both sides. An image (first image) of the light source unit (LD light source Md) is formed at the conjugate position by the optical system including the condenser lens 207. In terms of FIG. 4, it is the position after passing through the color wheel 208. The excitation light (LD light source light) is guided obliquely with respect to the optical axis (i.e., crossing the optical axis) near the conjugate position when the optical axis of the condenser lens 207 is viewed from the direction of the paper surface, and forms an image (first image) of the LD light source Md. Before and after the formation of the image of the LD light source Md, as shown in FIG. 4, it follows an optical path as if crossing the optical axis.

[0033] FIG. 9 is a diagram showing an example of the configuration of a color wheel included in the projector according to the first embodiment. In the present embodiment, the color wheel 208 is divided into four regions: a blue region B, a yellow region Y, a red region R, and a green region G. The blue region B corresponds to the excitation light reflection region 206b of the phosphor wheel 206 shown in FIG. 5, and the color wheel 208 and the phosphor wheel 206 rotate synchronously so that the yellow region Y, the red region R, and the green region G respectively correspond to the phosphor regions 206a of the phosphor wheel 206.

[0034] A transmissive diffuser plate (an example of a diffusing member) that diffuses the light beam of the LD light source light emitted from the second optical system 205 and the condenser lens 207 is disposed in the blue region B at a position shifted from the position of the conjugate image plane X2 where the first image is formed. In the present embodiment, by disposing the transmissive diffuser plate at a position shifted from the conjugate position of the light source optical system that creates a position substantially conjugate to the LD light source Md, it is possible to reduce the coherence of the LD light source Md and reduce the speckle on the screen. The yellow region Y transmits the yellow wavelength region emitted from the phosphor wheel 206 as it is. Further, the red region R and the green region G each use a dichroic mirror 204 to reflect light in an unnecessary wavelength region from the yellow wavelength and obtain light of a highly pure color. By the color wheel 208, the colors created temporally are guided to the image forming element 105 through the illumination optical system 104, an image (screen projection image) corresponding to each color is formed, and the color image is obtained by magnifying and projecting it onto the screen by the projection optical system 106.

[0035] The input current amount of the laser light source 201 can be changed for the LD light source Md corresponding to each region of the color wheel 208. Without changing the expected value of the input current amount to the LD light source in one cycle of the color wheel 208, by reducing the LD light source light of blue with low visibility and increasing the LD light source light of red, green, and yellow, the luminance can be increased without increasing the power consumption of the laser light source 201.

[0036] Next, an example of the specific configuration of the projector 101 according to the present embodiment will be described. As shown in FIG. 4, the first optical system 203 has a positive lens and a negative lens on the incident side of the excitation light, and the second optical system 205 (condensing optical system) has an aspherical lens and a plano-convex lens having positive power, and the condensing lens 207 has a biconvex lens. The following Table 1 shows the lens data of the first optical system 203 and the second optical system 205 (condensing optical system). Those with an asterisk in the surface number in Table 1 indicate aspherical surfaces.

Table 1

[0037] Further, the condensing lens 207 has lens data as shown in the following Table 2, and is arranged at an interval of 32 mm from the vertex on the incident side of the excitation light of the second optical system 205 (condensing optical system).

Table 2

[0038] The deviation amount ΔL between the first optical system 203 and the second optical system 205 (condensing optical system) is 2.35 mm, the outer diameter of the lens on the incident side of the second optical system 205 (condensing optical system) is 23.5 mm, and the outer diameter of the lens on the emission side of the first optical system 203 is 12.3 mm. Further, the combined magnification β of the second optical system 205 (condensing optical system) and the condensing lens 207 is 2.88.

[0039] FIG. 10 is a diagram showing an example of the configuration of an LD light source included in the projector according to the first embodiment. As shown in FIG. 10, for the LD light source Md, a light source in which laser light sources (LDs) 201 are arranged on a two-dimensional array is used. In the present embodiment, a module in which a plurality of laser light sources 201 are arranged is referred to as an LD light source Md, and the laser light source 201 is assumed to be a semiconductor laser. The laser light source 201 may be not limited to an LD but an individual light-emitting element such as an LED (Light Emitting Diode), but will be described on the premise of an LD. As the laser light source 201, for example, one in which an LD is arranged in a metal block or a multi-chip product in which LD chips are arranged in an array on one substrate can be used.

[0040] In the present embodiment, among the laser light sources 201 arranged in an array included in the LD light source Md, five laser light sources 201 are arranged in the X-axis direction and four laser light sources 201 are arranged in the Y-axis direction. The distance between adjacent laser light sources 201 in the X-axis direction is Px (= 3.5 [mm]), and the distance between adjacent laser light sources 201 in the Y-axis direction is Py (= 6.0 [mm]). Also, assuming the X-axis direction is the left-right direction, the distance from the leftmost laser light source 201 to the rightmost laser light source 201 is Lx (= 14.0 [mm]), and assuming the Y-axis direction is the up-down direction, the distance from the uppermost laser light source 201 to the lowermost laser light source 201 is Ly (= 18.0 [mm]). Also, when the distance between any two laser light sources 201 is S and the maximum distance is Smax, the distance S between two points in the diagonal direction is the largest, so this is set as Smax (= 22.8 [mm]).

[0041] However, the number of laser light sources 201 is not limited to 5×4, and may be 3×5 or 4×6, and is not particularly limited. Also, the arrangement of the laser light sources 201 may be a square arrangement, but in the present embodiment, it works most effectively when the first image and the second image, which are conjugate images of the LD light source Md to be described later, have a rectangular shape with long sides and short sides matching the shape of the image forming element 105. Therefore, it is desirable that the LD light source Md forming the first image and the second image is also rectangular.

[0042] However, in the present embodiment, the arrangement of the laser light sources 201 is arranged to be rectangular according to the shape of the image forming element 105. For example, the substrate on which the laser light sources 201 are arranged may be circular or may have an arbitrary shape such as a polygon, and the arrangement of the laser light sources 201 on the substrate is not limited.

[0043] FIG. 11 is a diagram showing an example of a laser light source and a collimator lens included in the projector according to the first embodiment. When the distance from the laser light source 201 to the incident surface of the collimator lens 202 is L (= 4.3 mm) and the direction of the maximum divergence angle among the divergence angles of the laser light source 201 is X, the divergence angle in the X direction is set to θx (= 45°).

[0044] FIG. 12 is a diagram showing an example of the arrangement of laser light sources in the LD light source included in the projector according to the first embodiment. In the present embodiment, as shown in FIG. 12, the LD light source Md includes an arrangement region in which a plurality of laser light sources 201 are arranged. In the present embodiment, the arrangement region is a substantially rectangular region having a short side and a long side. And, as shown in FIG. 12, the arrangement region is divided into one or more divided regions R1 to R4 (hereinafter, when not distinguishing the divided regions R1 to R4, described as the divided region R) including one or more laser light sources 201. Further, the LD light source Md functions as an example of a light source unit in which the dividing directions of the plurality of divided regions R1 to R4 in the arrangement region are substantially aligned. In the present embodiment, the dividing directions of the plurality of divided regions R1 to R4 are parallel to the long side of the arrangement region. Each laser light source 201 in each divided region R may have a light quantity distribution for each divided region R by changing the LD output. For example, the laser light sources 201 may be connected in series for each divided region R to have the same LD output. Also, the input current amount to the common laser light source 201 can be set for each divided region R, and the laser light source 201 can be driven for each divided region R. In the present embodiment, an example in which the arrangement region of the LD light source Md is divided into four divided regions R1 to R4 in the direction in which many laser light sources 201 are arranged is described, but the number of divided regions R is not limited to this.

[0045] FIG. 13 is a diagram showing an example of the profiles of the light spots immediately after the collimator lens and on the phosphor in the projector according to the first embodiment. FIG. 13(a) shows the profile of the light spot when the pitch of the array-shaped laser light sources 201 of the LD light source Md is large, and FIG. 13(b) shows the profile of the light spot when the pitch of the array-shaped laser light sources 201 of the LD light source Md is small.

[0046] When trying to make the overall size B of the profile of the light spot on the phosphor region 206a (phosphor) of the phosphor wheel 206 the same, if the pitch of the laser light sources 201 is large, the reduction magnification has to be made larger than when the pitch of the laser light sources 201 is small. Therefore, the size of each light spot on the phosphor region 206a becomes small, the condensing density increases, and the conversion efficiency of the phosphor region 206a decreases. On the other hand, if the pitch of the laser light sources 201 is appropriate, as shown in FIG. 13(b), since each light spot is arranged so as to fill the space, a uniform distribution is obtained on the phosphor region 206a, the condensing density can be reduced, and the conversion efficiency can be improved.

[0047] FIG. 14 is a diagram showing an example of the distribution of the incident angle of the excitation light with respect to the phosphor wheel in the projector according to the first embodiment. In the projector 101 according to the present embodiment, as shown in FIG. 14, it can be seen that the incident angles of the light rays in the range where the peak intensity of the excitation light with respect to the phosphor wheel 206 is 1 / e^2 or more are distributed between 0 degrees and 50 degrees. Thereby, it becomes possible to suppress the reflectance by the surface on the phosphor wheel 206 side of the second optical system 205 (condensing optical system), and the efficiency is improved.

[0048] FIG. 15 is a diagram showing an example of the spot shape on the phosphor wheel and the spot shape at the entrance of the light tunnel in the projector according to the first embodiment. The short side SE of the opening surface of the light tunnel LT is 3.4 mm, and the long side LE is 5.7 mm.

[0049] In the projector 101 according to the present embodiment, as shown in FIG. 15, it can be seen that light enters the entrance of the light tunnel LT with almost no divergence of light rays. Further, in order to obtain a more uniform distribution on the exit surface of the light tunnel LT, it is preferable that light enters the entrance surface of the light tunnel LT with almost no divergence of light rays and with a uniform distribution. For this purpose, in each divided region R of the LD light source Md, the long side direction of the first image of the opening surface of the light tunnel LT (that is, the longitudinal direction of the opening of the light tunnel LT) and the dividing direction of the divided region R of the LD light source Md (the array direction of the images of the divided region R in the first image) are aligned, and the long side direction and the short side direction of the light tunnel LT are aligned with the first image. Thereby, it is possible to obtain a more uniform distribution because the light can be incident on the light tunnel LT so as to emit light in the short side direction of the opening of the light tunnel LT, and the light quantity distribution can be expanded in the long side direction of the light tunnel LT. However, the dividing direction of the divided region R of the LD light source Md is not limited to this. Further, in the present embodiment, the light beam of the LD light source light emitted from the second optical system 205 and the condenser lens 207 passes near the optical axis of the second optical system 205 and the condenser lens 207 along the array direction of the images of the divided region R on the conjugate image plane X2.

[0050] FIGS. 16 and 17 are diagrams showing an example of a first image formed on the opening surface of the light tunnel included in the projector according to the first embodiment. In the present embodiment, as shown in FIG. 13, on the conjugate image plane X2, the image (first image) of each laser light source 201 of the LD light source Md is substantially elliptical. As shown in FIG. 16, since the longitudinal direction of the ellipse is aligned with the longitudinal direction of the opening of the light tunnel LT, light can enter the entrance of the light tunnel LT with less divergence of light rays. Further, as shown in FIG. 17, when the short side direction of the ellipse is aligned with the longitudinal direction of the light tunnel LT, the number of laser light sources 201 arranged in the longitudinal direction of the light tunnel LT increases, but by changing the LD output, color unevenness and luminance unevenness can be adjusted more finely with respect to the left-right direction of the screen projection image.

[0051] FIG. 18 is a diagram for explaining an example of the generation process of a screen projection image by the projector according to the first embodiment. FIG. 18 shows the optical paths of the blue excitation light and the fluorescence light for generating the screen projection image projected onto the screen SC.

[0052] The blue excitation light from the LD light source Md is irradiated onto the phosphor region 206a and the excitation light reflection region 206b of the phosphor wheel 206, and is thus divided into two types: blue excitation light and fluorescence light. In FIG. 18, for the sake of easy understanding, the optical paths between the phosphor wheel 206 and the light tunnel LT are drawn vertically side by side corresponding to the segments (phosphor region 206a, excitation light reflection region 206b) of the phosphor wheel 206 in FIG. 18. However, in reality, since the phosphor wheel 206 rotates and the phosphor moves onto the optical path of the blue excitation light, the optical paths are in the same space. The fluorescence light is emitted from the phosphor layer (phosphor region 206a) at an angle close to Lambertian light and enters the light tunnel LT. On the other hand, the blue excitation light is condensed until it is reflected by the excitation light reflection region 206b of the phosphor wheel 206 and passes through the diffusion region of the color wheel 208. Therefore, as shown by the different arrow sizes of the blue excitation light and the fluorescence light in FIG. 18, the light quantity distributions at the opening surface of the light tunnel LT for the blue excitation light and the fluorescence light are different.

[0053] Humans perceive by synthesizing the screen projection image on the screen composed of the blue excitation light generated in a time-division manner and the screen projection image on the screen SC composed of the fluorescence light. If the shapes of the synthesized light quantity distributions are different, for example, as in the screen projection image shown in FIG. 18, since the illuminance differences are different between the central part and the peripheral part, humans will perceive it as color unevenness.

[0054] FIGS. 19 and 20 are cross-sectional conceptual diagrams of the central part of the screen projection image cut in the horizontal direction. In FIGS. 19 and 20, the horizontal axis represents the horizontal position of the central part of the screen projection image, and the vertical axis represents the luminance. In FIGS. 19 and 20, assuming that the LD light source Md emits the same light quantity in all divided regions R, the cross-sections of the light quantity distributions of the blue excitation light and the fluorescence light are graphed.

[0055] Below the graphs in FIGS. 19 and 20, the light emission amounts for each divided region R of the LD light source Md are represented by three lines. Briefly, this number represents the magnitude of the light amount of the laser light source 201, and the larger the number, the larger the light amount and the higher the illuminance. In the case of the light amount distribution in FIG. 19, the blue excitation light has a high illuminance in the left-right direction of the screen SC, and the fluorescent light has a high illuminance in the central part of the screen SC. Therefore, the illuminance difference is different between the central part and the peripheral part of the screen SC. This difference in illuminance difference results in color unevenness when the screen projection image of the blue excitation light and the screen projection image of the fluorescent light are combined. On the other hand, as shown in FIG. 20, when the illuminance difference does not change at any position on the screen SC with respect to the light amount distribution of the blue excitation light and the light amount distribution of the fluorescent light, projection can be performed without color unevenness.

[0056] FIG. 21 is a diagram showing an example of the light amount distribution of the blue excitation light and the fluorescent light when the light tunnel is made sufficiently long. As a method of taking color unevenness in the screen projection image, for example, there is a method of lengthening the light tunnel LT. For example, as shown in FIG. 21, when the length of the light tunnel LT is in the gray region, the light amount distributions of the blue excitation light and the fluorescent light shown in FIG. 19 are obtained. Assume that when the length of the light tunnel LT is increased, the light amount distributions of the blue excitation light and the fluorescent light shown in FIG. 21 can be obtained.

[0057] When the light tunnel LT is lengthened, as in the light amount distribution shown in FIG. 21, the light amount distributions of both the blue excitation light and the fluorescent light can obtain a uniform light amount distribution in the left-right direction of the screen SC, and color unevenness can be improved. However, by lengthening the light tunnel LT, the optical system becomes larger, leading to an increase in the size of the projector 101. Therefore, in the present embodiment, the arrangement region of the LD light source Md is divided into a plurality of divided regions R, and by changing the LD output between the plurality of divided regions R, color unevenness in the screen projection image is reduced. For example, in the present embodiment, the projector 101 changes the LD output of at least one laser light source 201 included in each divided region R.

[0058] FIG. 22 is a diagram showing an example of the light quantity distribution of blue excitation light and fluorescent light in the projector according to the first embodiment. As shown in FIG. 22, when the illuminance of the blue excitation light is high around the screen SC, by reducing the LD outputs of the divided regions R1 and R4, the light quantity distribution of the screen projection image of the blue excitation light can be made to match the light quantity distribution of the screen projection image of the fluorescent light, and color unevenness can be eliminated. That is, the projector 101 changes the LD output of each divided region R so that the light quantity distribution of the LD source light emitted from the LD source Md matches the light quantity distribution of the fluorescent light emitted from the phosphor wheel 206 on the screen SC. FIG. 22 shows the light quantity distribution of the blue excitation light and the light quantity distribution of the fluorescent light with the LD outputs of the divided regions R1 and R4 reduced compared to the LD outputs of the divided regions R2 and R3. The LD power source at the bottom of the graph shown in FIG. 22 represents the LD outputs of the divided regions R1 and R4 by a single line and the LD outputs of the divided regions R2 and R3 by a triple line, indicating that the LD outputs of the divided regions R2 and R3 are larger.

[0059] As a method for reducing color unevenness, for the sake of easy understanding, attention was paid to the color unevenness in the horizontal direction of the screen SC, but it is desirable to reduce color unevenness also for the two-dimensional light quantity distribution including the vertical direction of the screen SC. Here, that the light quantity distribution of the screen projection image composed of excitation light matches the light quantity distribution of the screen projection image composed of fluorescent light means, for example, in the two-dimensional light quantity distribution acquired from the illuminance meter, the error of the maximum illuminance difference between the excitation light and the fluorescent light is within 50% (preferably within 30%) at any position of the light quantity distribution. When the light quantity distribution of the screen projection image composed of excitation light matches the light quantity distribution of the screen projection image composed of fluorescent light, it can be said that the color unevenness is improved. Also, when the illuminance difference of the two-dimensional light quantity distribution is made into a histogram, it is sufficient if it is satisfied in an area of 68% or more, and preferably, if the illuminance difference is within 50% to 30% in an area of 95% or more.

[0060] If the shape of the horizontal light quantity distribution on the screen SC is different, humans will perceive it as brightness unevenness. For example, as shown in FIG. 21, when there is a constant light quantity distribution in the horizontal direction on the screen SC, no brightness unevenness occurs. On the other hand, in the case of the light quantity distribution as shown in FIG. 22 in the horizontal direction on the screen SC, the central part of the screen SC is bright and the peripheral part is dark. Therefore, it is preferable that the two-dimensional light quantity distribution including the vertical direction on the screen SC provides uniform illuminance at any position of the screen projection image.

[0061] Therefore, the LD output between the divided regions R1 to R4 of the LD light source Md may be changed so that the luminance of the light quantity distribution of the screen projection image composed of fluorescent light becomes uniform. That is, the projector 101 according to the present embodiment changes the LD output of the LD light source Md so that the light quantity distribution of the fluorescent light emitted from the phosphor wheel 206 becomes uniform at the screen SC (an example of a desired irradiation position). Then, by matching the light quantity distribution of the excitation light with the light quantity distribution of the wavelength-converted light (fluorescent light) that has been made uniform, both brightness unevenness and color unevenness can be improved.

[0062] FIG. 23 is a diagram showing an example of the horizontal light quantity distribution at a certain position of the screen projection image. For example, when the light quantity distribution of the screen projection image in the case where all pixels of the input image are the same color (for example, white) is the light quantity distribution shown in FIG. 23, the illuminance difference between the maximum illuminance of the wavelength-converted light (fluorescent light) emitted from the phosphor wheel 206 and the average illuminance of the entire screen SC is within 50% (more preferably within 30%) with respect to the maximum illuminance, the light quantity distribution is called uniform. Also, when the illuminance difference of the two-dimensional light quantity distribution is made into a histogram, it is sufficient to satisfy that the illuminance difference is within 50% in an area of 68% or more, and preferably the illuminance difference is within 50% to 30% in an area of 95% or more.

[0063] From the above, when reducing the luminance unevenness of the light quantity distribution of the screen projection image with respect to the screen SC, it is preferable to change the LD output between the divided regions R1 to R4 at the timing of irradiating the phosphor region 206a of the phosphor wheel 206 with excitation light. Further, when reducing the color unevenness of the light quantity distribution of the screen projection image, it is preferable to change the LD output between the divided regions R1 to R4 at the timing of irradiating the screen SC with blue excitation light.

[0064] The reason for this is that since the blue excitation light has a lower scotopic sensitivity than the wavelength-converted light, the color unevenness can be adjusted while having less influence on the luminance unevenness. Conversely, since the fluorescence light has a higher scotopic sensitivity than the blue excitation light, it is possible to adjust the luminance unevenness by changing the LD output between the divided regions R1 to R4 when irradiating the screen projection image with the fluorescence light.

[0065] FIG. 24 is a diagram showing an example of the correspondence relationship of the light quantity distribution of the LD light source, the opening surface of the light tunnel, and the screen projection image in the projector according to the first embodiment. FIG. 25 is a diagram showing an example of the light quantity distribution of the light emitting surface of the LD light source of the projector according to the first embodiment. FIG. 26 is a diagram showing an example of the light quantity distribution of the opening surface of the light tunnel of the projector according to the first embodiment. FIG. 27 is a diagram showing an example of the light quantity distribution of the screen projection image of the projector according to the first embodiment. The light quantity distributions shown in FIGS. 24 to 27 are the light quantity distributions when only the specific laser light source 201 is lit, instead of changing the LD output for each divided region R, in order to show the correspondence relationship of the light quantity distributions of the LD light source Md, the opening surface of the light tunnel LT, and the screen projection image.

[0066] In this embodiment, when the divided region R above the LD light source Md, for example, the divided region R1 emits light, the illuminance of the light quantity distribution on the left side of the screen projection image increases. When the divided region R below the LD light source Md, for example, the divided region R4 emits light, the illuminance of the light quantity distribution on the right side of the screen projection image increases. However, the optical path may be folded back using a mirror to change the correspondence relationship between the light quantity distributions of the light emitting surface of the LD light source Md and the opening surface of the light tunnel LT, or the correspondence relationship between the light quantity distributions of the opening surface of the light tunnel LT and the screen projection image may be changed.

[0067] The LD light source Md, the incident position of the light tunnel LT, the exit of the light tunnel LT, the image forming element 105, and the screen SC are each in an optically conjugate relationship. Depending on the folding by the mirror and the presence or absence of an intermediate image, the LD light source Md, the incident position of the light tunnel LT, the exit of the light tunnel LT, the image forming element 105, and the screen SC are inverted vertically or horizontally. For the purpose of explaining this embodiment, in FIG. 24, schematically, the positions of the individual LD light sources Md, the positions on the light tunnel LT, and the position of the screen SC are shown.

[0068] The light quantity distribution of the opening surface of the light tunnel LT shown in FIG. 25 has the horizontal axis representing the horizontal direction of the multi-chip of the LD light source Md, and the vertical axis representing the vertical direction of the multi-chip of the LD light source Md. The light quantity distribution shown in FIG. 25 becomes a whiter distribution as the illuminance is higher. When the two laser light sources 201 on the right side of the divided region R1 and the one laser light source 201 on the left side of the divided region R4 are lit as in the LD light source Md shown in FIG. 24, the illuminance at the position corresponding to the lit laser light source 201 in the light quantity distribution shown in FIG. 25 increases.

[0069] The light quantity distribution shown in Fig. 25 has the short side direction of the multi-chip of the LD light source Md as the horizontal axis (corresponding to the vertical direction on the screen SC when projecting a horizontally long screen), and the long side direction of the multi-chip of the LD light source Md as the vertical axis (similarly corresponding to the horizontal direction on the screen). The higher the illuminance, the whiter the distribution. As shown in the LD light source Md of Fig. 24, when lighting two laser light sources 201 on the right side of the divided region R1 and one laser light source 201 on the left side of the divided region R4, the illuminance at the position corresponding to the lit laser light source 201 in the light quantity distribution shown in Fig. 25 is high.

[0070] The light quantity distribution of the opening surface of the light tunnel LT shown in Fig. 26 has the horizontal direction corresponding to the short side SE of the light tunnel LT and the vertical direction corresponding to the long side LE of the light tunnel LT, and has the same light quantity distribution as the light quantity distribution of the light emitting surface of the LD light source Md shown in Fig. 25. The light quantity distribution on the screen SC shown in Fig. 27 has the region with the lowest illuminance as the region where the screen SC is not projected. In order to uniformize the blue excitation light incident on the light tunnel LT, the light quantity distribution projected on the screen SC cannot distinguish the light emitting positions of the laser light sources 201. However, the gradient of the light quantity distribution corresponds to the light emitting positions of the laser light sources 201. When lighting two laser light sources 201 on the right side in the divided region R1, on the screen SC, a light quantity distribution with a peak at the lower left appears.

[0071] FIG. 28 is a diagram showing an example of the functional configuration of a projector according to the first embodiment. The light source device 102 included in the projector 101 according to this embodiment includes an LD light source Md that is an excitation light source that emits excitation light, a phosphor wheel 206 as a wavelength conversion member that is disposed on the optical path of the excitation light and is excited by the excitation light to generate fluorescence in a predetermined wavelength band, a color wheel 208 that is disposed on the optical path of the excitation light and extracts four of a blue region B, a yellow region Y, a red region R, and a green region G from the excitation light and the fluorescence generated from the phosphor wheel 206, a light source unit control means 130 that performs emission control of the LD light source Md and phase control of the phosphor wheel 206 and also performs emission control of the LD light source Md and phase control of the phosphor wheel 206, and a second optical system 205 that collects (condenses) and emits the fluorescence generated from the phosphor wheel 206. The phosphor wheel 206 is attached to a rotation shaft 12c of a motor unit 12d (drive motor 801 shown in FIG. 8) that is a driving means such as an electric motor. The motor unit 12d is driven and controlled by a motor driving unit 17. Further, the color wheel 208 is attached to a rotation shaft 13c of a motor unit 13d that is a driving means such as an electric motor. The motor unit 13d is also driven and controlled by the motor driving unit 17.

[0072] The motor unit 12d has a function of generating a rotation detection signal MIDX1 indicating the rotation speed of the rotation shaft 12c and outputting it to the motor driving unit 17. This function may be provided inside the motor unit 12d or may be externally attached to the motor unit 12d. When this function is implemented externally, for example, an optical mark is provided on the rotation shaft 12c of the motor unit 12d or a part of a component that rotates together with this rotation shaft 12c, and a method of detecting the mark using a photosensor or the like is generally known. That is, each time the photosensor detects the mark, it generates a pulse and outputs a rotation detection signal MIDX1. Similarly to the above, the motor unit 13d also has a function of generating a rotation detection signal MIDX2 indicating the rotation speed of the rotation shaft 13c and outputting it to the motor driving unit 17.

[0073] The light source unit control means 130 includes a synchronization signal generation unit 15 that outputs a synchronization signal at a fixed period, an LD drive unit 16 that controls the light emission (turning on and off) of the LD light source Md, a motor drive unit 17 that controls the phases of the motor unit 12d of the phosphor wheel 206 and the motor unit 13d of the color wheel 208, a control unit 14 that controls these units, and a memory 18 that stores various data such as the light emission timing data of the LD light source Md, the light emission period, and the rotation phase data of the motor units 12d and 13d. Further, the LD drive unit 16, the motor drive unit 17, and the control unit 14 of the light source unit control means 130 are connected to the memory 18 via a memory bus (MBI) 20.

[0074] As the hardware configuration of the light source unit control means 130, it has a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The light source unit control means 130 drives and controls the LD light source Md, the phosphor wheel 206, and the color wheel 208 according to a program pre-stored in the ROM, using the RAM as a work memory.

[0075] The synchronization signal generation unit 15 has a function of outputting a synchronization signal SYNC (SYN_O) with a fixed period T0. Based on the output timing of this synchronization signal SYN_O, phase control of the motor units 12d and 13d by the motor drive unit 17 and light emission control of the LD light source Md by the LD drive unit 16 are performed. For example, when a periodic signal SYN_I is input to the synchronization signal generation unit 15 from the outside via an HDMI (registered trademark) cable, the synchronization signal generation unit 15 outputs a signal with the same period and phase as this periodic signal SYN_I as the synchronization signal SYN_O. As another different example of the output procedure of this synchronization signal SYN_O, a signal with an arbitrary period and phase may be generated inside the synchronization signal generation unit 15 and output as the synchronization signal SYN_O. The synchronization signal SYN_O is output to the LD drive unit 16 and the motor drive unit 17.

[0076] When the activation signal ST input from the outside is asserted via the external interface, the control unit 14 has a function of outputting a motor activation signal MST to the motor drive unit 17. Further, when a signal MGD that notifies that both the motor unit 12d and the motor unit 13d are in a normal rotation state is asserted from the motor drive unit 17, the control unit 14 asserts an LD light emission start signal LDEN and outputs it toward the LD drive unit 16.

[0077] When the motor activation signal MST from the control unit 14 is asserted, the motor drive unit 17 has a function of outputting a motor drive signal MTD to start driving the motor units 12d and 13d. The motor drive unit 17 further has a function of detecting the period of the rotation detection signal (phase signal) MIDX1 from the motor unit 12d of the phosphor wheel 206. Similarly, the motor drive unit 17 has a function of detecting the period of the rotation detection signal MIDX2 from the motor unit 13d of the color wheel 208. More specifically, when the motor activation signal MST is asserted, the motor drive unit 17 monitors whether or not the rotation detection signal MIDX1 has reached a predetermined period after the motor unit 12d of the phosphor wheel 206 starts outputting the rotation detection signal MIDX1. Similarly, the motor drive unit 17 monitors whether or not the rotation detection signal MIDX2 has reached a predetermined period after starting to output the rotation detection signal MIDX2 to the motor unit 13d of the color wheel 208. When the motor drive unit 17 detects that the rotation detection signal MIDX1 has reached a predetermined period, it asserts a signal MGD1 that notifies that the motor unit 12d of the phosphor wheel 206 is in a normal rotation state and outputs it to the control unit 14. Further, when the motor drive unit 17 detects that the rotation detection signal MIDX2 has reached a predetermined period, it asserts a signal MGD2 that notifies that the motor unit 13d of the color wheel 208 is in a normal rotation state and outputs it to the control unit 14.

[0078] The motor drive unit 17 has a function of controlling the phases of the motor units 12d and 13d respectively. For this control, the motor drive unit 17 has a register R3 internally, reads the rotation phase data T3 of the motor unit 12d of the phosphor wheel 206 stored in the memory 18, and stores it in the register R3. Then, after confirming that the motor unit 12d has entered a normal rotation state, the motor drive unit 17 detects the phase of the rotation detection signal MIDX1 with respect to the synchronization signal SYN_O (period T0), and compares the phase difference with the content of the register R3. The motor drive unit 17 controls the motor drive signal MTD so that this phase difference matches the rotation phase data T3 stored in the register R3. Specifically, in this embodiment, a three-phase brushless DC motor is used as the motor unit 12d, and the motor drive unit 17 generates a three-phase current signal as the motor drive signal MTD1. And for this three-phase current signal, it can be achieved by controlling the phase with respect to the synchronization signal SYN_O.

[0079] Similarly, the motor drive unit 17 has a register R4 internally, reads the rotation phase data T4 of the motor unit 13d of the color wheel 208 stored in the memory 18, and stores it in the register R4. Then, after confirming that the motor unit 13d of the color wheel 208 has entered a normal rotation state, the motor drive unit 17 detects the phase of the rotation detection signal MIDX2 with respect to the synchronization signal SYN_O (period T0), and compares the phase difference with the content of the register R4. The motor drive unit 17 controls the motor drive signal MTD so that this phase difference matches the rotation phase data T4 stored in the register R4. Specifically, in this embodiment, a three-phase brushless DC motor is used as the motor unit 13d, and the motor drive unit 17 generates a three-phase current signal as the motor drive signal MTD2. And for this three-phase current signal, it can be achieved by controlling the phase with respect to the synchronization signal SYN_O.

[0080] When the LD emission start signal LDEN is affirmed, the LD drive unit 16 outputs an LD drive signal LDD for driving (emitting light) the laser light source 201 of the LD light source Md by a predetermined light emission start timing (start period T1), a predetermined light emission period (light emission period T2), and a predetermined light emission amount with respect to the synchronization signal SYN_O. The start period T1 is the phase from when the LD drive signal LDD is output until the LD emits light, and is used for correction. The light emission period T2 is the time for one rotation of the phosphor wheel 206 or the color wheel 208. For example, when rotating at 120 Hz, the light emission period T2 is approximately 8.3 ms, which is 1 / 120 second. Note that the phosphor wheel 206 and the color wheel 208 rotate at the same speed. In this embodiment, the light emission amount of the laser light source 201, which is a predetermined light emission amount, outputs the input current amounts D10, D11, D12, D13 of the four divided regions R1 to R4 as the LD drive signal LDD during the start period T1 and the light emission period T2.

[0081] As an example of the specific configuration and operation of the LD drive unit 16, it can be realized as follows. First, in this embodiment, the LD drive unit 16 internally has six registers R1, R2, DR10, DR11, DR12, DR13 that read and store the light emission start timing T1, the light emission period T2, and the input current amounts D10, D11, D12, D13 stored in the memory 18, and two timers TM1, TM2. Let the time count values of the timers TM1 and TM2 be t10 and t20, respectively. After the LD emission start signal LDEN is affirmed from the control unit 14, the LD drive unit 16 starts the timer TM1 at a predetermined timing with respect to the synchronization signal SYN_O. When the time count value t10 of this timer TM1 matches the light emission start timing T1 of the register R1, the output of the LD drive signal LDD is started and the timer TM2 is started, and the LD light source Md is turned on by outputting the LD drive signal LDD with the input current amounts D10, D11, D12, D13. Also, when the time count value t20 of this timer TM2 matches the light emission period T2 of the register R2, or at the earlier timing of the output timing of the synchronization signal SYN_O in the next cycle, the output of the LD drive signal LDD is stopped and the LD light source Md is turned off.

[0082] The memory 18 stores, as information, the rotation phase data T3 of the motor unit 12d of the phosphor wheel 206 described above, the rotation phase data T4 of the motor unit 13d of the color wheel 208 described above, the light emission start T1 and the light emission period T2 of the LD light source Md, and the input current amounts D10, D11, D12, D13 at the light emission timing of the light emission period T2. These pieces of information are read out from the memory 18 via the memory bus (MBI) 20, for example, when the power supply of the light source device 10 is turned on, and written (stored) into the register R3 and register R4 of the motor drive unit 17 and the registers R1, R2, DR10, DR11, DR12, DR13 of the LD drive unit 16. Thereby, the operation of the light source device 10 reflecting the content of the memory 18 can be realized. Further, as the memory 18, a RAM may be used, or an external storage device such as an HDD or a USB can be used.

[0083] Note that the rotation phase data T3, the rotation phase data T4, the light emission start timing T1, the light emission period T2, and the input current amounts D10, D11, D12, D13 stored in the memory 18 can be rewritten from the outside. Specifically, a control signal CNT is input to the control unit 14 from the outside, and this control signal CNT includes an interface signal with the outside. Based on this interface signal, the control unit 14 rewrites the rotation phase data T3 of the phosphor wheel 206 in the memory 18, the rotation phase data T4 of the color wheel 208, the light emission start T1 for controlling the light emission of the LD light source Md, or the light emission period T2. By making the content of the memory 18 rewritable in this way, for example, when an illumination device including the light source device 102 is used in an image display device or a projection display device, the following operation becomes possible. That is, the frame frequency of the output video signal to be projected may change depending on the type and frame frequency of the video signal input to these image display devices or projection display devices. By rewriting the data in the memory 18 in response to such a change in the frame frequency or the like, it is possible to emit fluorescence (illumination light) corresponding to the frame frequency, and to suppress luminance unevenness and the like, and emit fluorescence with a good light emission state.

[0084] FIG. 29 is a flowchart showing an example of the operation flow of a light source device included in the projector according to the first embodiment. FIG. 30 is a timing chart of signal control for driving the LD light source in the projector according to the first embodiment. In the timing chart shown in FIG. 30, the horizontal axis represents time, and the vertical axis represents the synchronous signal SYN_I, the rotation detection signal MIDX1 of the phosphor wheel 206, the rotation detection signal MIDX2 of the color wheel 208, and the signal value of the LD drive signal LDD, which are triggers for the light emission of the LD light source Md. When the signal is OFF, the signal value is "0", and when the signal is ON, the signal value is "1".

[0085] First, when the start signal ST input from the outside via the external interface is affirmed, the control unit 14 inputs the synchronous signal SYN_I to the synchronous signal generation unit 15, and the synchronous signal generation unit 15 outputs the synchronous signal SYN_O with a period T0 (step S2901). Further, when the start signal ST is affirmed, the motor drive unit 17 outputs the motor start signal MST1 of the phosphor wheel 206 and the motor start signal MST2 of the color wheel 208 (step S2902).

[0086] When both the motor start signals MST1 and MST2 are affirmed, the motor drive unit outputs the motor drive signal MTD1 of the phosphor wheel 206 composed of the three-phase current signals Iu1, Iv1, Iw1 and the motor drive signal MTD2 of the color wheel 208 composed of the three-phase current signals Iu2, Iv2, Iw2 to the motor units 12d and 13d, and starts driving the motor units 12d and 13d (step S2903). The motor units 12d and 13d are rotationally driven by these motor drive signals MTD1 and MTD2, and the rotation detection signal MIDX1 of the phosphor wheel 206 and the rotation detection signal MIDX2 of the color wheel 208 are output to the motor drive unit 17 (step S2904).

[0087] The motor drive unit 17 acquires the phase data of the rotation detection signal MIDX1 of the phosphor wheel 206 and the phase data of the rotation detection signal MIDX2 of the color wheel 208 with respect to the synchronization signal SYN_O. Then, the motor drive unit 17 determines whether the rotation phase data T3 of the register R3 of the phosphor wheel 206 matches the rotation detection signal MIDX1 (step S2905). Similarly, the motor drive unit 17 determines whether the rotation phase data T4 of the register R4 of the color wheel 208 matches the rotation detection signal MIDX2 (step S2905).

[0088] When the rotation phase data T3 of the register R3 of the phosphor wheel 206 does not match the rotation detection signal MIDX1, for example, when the rotation detection signal MIDX1 does not match the rotation phase data T4 of the register R3 during the rising of the drive of the motor unit 12d, such as when the rotation of the motor unit 12d is in the middle of rising at the start of the drive of the motor unit 12d, the motor drive unit 17 controls Iu1, Iv1, and Iw1 of the motor drive signal MTD1 and repeats the determination of whether the rotation phase data T3 matches the rotation detection signal MIDX1 (step S2905). The same process is performed for the color wheel 208.

[0089] When the rotation phase data T3 matches the rotation detection signal MIDX1 in the phosphor wheel 206 and the rotation phase data T4 also matches the rotation detection signal MIDX2 in the color wheel 208, assuming that both the phosphor wheel 206 and the color wheel 208 are in a normal rotation state of the motor units 12d and 13d, the motor drive unit 17 affirms the rotation normal signal MGD and outputs it to the control unit 14 (step S2906). That is, when at least one of them is not in a normal rotation state, the rotation normal signal MGD is not output to the control unit 14. When the rotation normal signal MGD is affirmed, the control unit 14 affirms the LD emission start signal LDEN and outputs it to the LD drive unit 16 (step S2907).

[0090] When the LD emission start signal LDEN is affirmed, the LD drive unit 16 outputs the LD drive signal LDD to the LD light source Md for the emission start timing T1 of the register R1 and for the emission period T2 of the register R2 with respect to the synchronization signal SYN_O, causing the LD light source Md to emit light.

[0091] When the LD light source Md is caused to emit light at the light emission start timing T1 with respect to the synchronization signal SYN_O, the LD light source Md will emit light with a delay of approximately the period of the light emission start timing T1. The delay of the light emission start timing T1 that occurs during the first light emission of the LD light source Md is allowed, and for the light emission timings after the second time, the LD light source Md is caused to emit light earlier by only the light emission start timing T1 so that the light emission timing becomes the same as that of the synchronization signal SYN_O, thereby synchronizing the light emission timing of the synchronization signal SYN_O and the LD light source Md. Not limited to this synchronization method, for example, an input current detection unit for the LD light source Md may be provided, and feedback control may be used so that the synchronization signal SYN_O arrives at the timing when the current is detected.

[0092] The LD light source Md stops the output of the LD drive signal LDD and turns off the LD light source Md at the earlier of the timing that coincides with the light emission period T2 and the timing at which the synchronization signal SYN_O of the next cycle is output. That is, the LD light source Md is turned on only for a period that satisfies MIN(T2, T0 - T1). Note that MIN(A, B) compares A and B and returns the same value or the smaller value.

[0093] By the above operations, as shown in the timing chart of FIG. 30, with respect to the synchronization signal SYN_O, in the first cycle of the phosphor wheel 206, the rotation detection signal MIDX1 from the motor unit 12d transitions from "0" to "1" after the period of the rotation phase data T3. After the second cycle and later, the rotation detection signal MIDX1 from the motor unit 12d is transitioned from "0" to "1" earlier by the period of the rotation phase data T3 than the previous cycle, thereby synchronizing the synchronization signal SYN_O and the phosphor wheel 206. The same processing as described above is also performed for the color wheel 208.

[0094] From the above, after the second cycle of the synchronization signal SYN_O, the timings of the light emission of the LD, the start of rotation of the phosphor wheel 206, and the start of rotation of the color wheel 208 can be made substantially simultaneous.

[0095] FIG. 31 is a timing chart for one cycle of the input current amount for each divided region of the laser light source included in the LD light source in the projector according to the first embodiment. In the present embodiment, the LD output between the divided regions R1 to R4 of the LD light source Md is made the same during the yellow period, red period, blue period, and green period in which the excitation light of the LD light source Md is incident on the yellow region Y, red region R, blue region B, and green region G of the color wheel 208, and the LD output (input current amounts D10, D11, D12, D13) is changed. By increasing the input current amounts D10, D11, D12, D13 during the red period, green period, and yellow period with high visibility and decreasing the input current amounts D10, D11, D12, D13 during the blue period with low visibility, the monochromatic luminance ratio can be improved without changing the power consumption.

[0096] Since the phosphor wheel 206 is divided into a phosphor region 206a coated with a phosphor and an excitation light reflection region 206b that reflects excitation light, the fluorescent light excited from the phosphor region 206a and the blue light emitted from the excitation light reflection region 206b are combined and projected onto the screen SC. That is, in order to obtain a uniform light amount distribution of color unevenness, it is necessary to approximate the light amount distribution obtained by the fluorescent light and the light amount distribution obtained by the blue light.

[0097] FIG. 32 is a diagram showing an example of the light quantity distribution of the fluorescent light projected onto the screen by the projector according to the first embodiment. FIG. 33 is a diagram showing an example of the light quantity distribution of the excitation light projected onto the screen by the projector according to the first embodiment. As shown in FIG. 32, the light quantity distribution of the fluorescent light projected onto the screen SC by the projector 101 according to the present embodiment has a peak at the lower center and the luminance (light quantity) decreases as it approaches the peripheral portion. On the other hand, as shown in FIG. 33, the light quantity distribution of the excitation light (blue excitation light) projected onto the screen SC by the projector 101 according to the present embodiment has peaks at the lower center and on its left and right, and is different from the light quantity distribution and its shape of the fluorescent light. Therefore, when the light quantity distribution of the fluorescent light shown in FIG. 32 and the light quantity distribution of the blue excitation light shown in FIG. 33 are synthesized, color unevenness occurs in the screen projection image on the screen SC in its horizontal direction and at the lower center.

[0098] Therefore, in the projector 101 according to the present embodiment, as a method for eliminating this color unevenness (in other words, a method for approximating the light quantity distribution of the fluorescence light and the light quantity distribution of the excitation light), a plurality of laser light sources 201 included in the LD light source Md are divided into a plurality of divided regions R as shown in FIG. 12, and the input current amounts D10, D11, D12, D13 (LD output) are controlled for each divided region R by the light source unit control means 130, thereby adjusting the light quantity distributions of the fluorescence light and the excitation light. As other methods for eliminating color unevenness, there are a method of making the light tunnel LT, which is a light homogenizing element, longer to homogenize the light quantity distribution, and a method of adjusting the position of the optical system so that the light quantity distributions of the fluorescence light and the excitation light are approximated. However, the method of making the light tunnel LT longer has a problem that the illumination optical system 104 becomes larger, leading to an increase in the size of the projector 101. Further, when adjusting the position of the optical system, it is not possible to cope with the occurrence of color unevenness due to mechanical differences after the product is shipped. Therefore, for example, when there are differences in color unevenness and luminance due to mechanical differences when superimposed use is desired, it can be adjusted by rewriting six registers R1, R2, DR10, DR11, DR12, DR13 that read and store the input current amounts D10, D11, D12, D13 from the outside. The method of changing the LD output between the divided regions R1 to R4 is simpler, and in addition to adjusting the light quantity distribution by optical design, the light quantity distribution can also be adjusted by controlling the LD output, so that the light quantity distribution can be controlled more finely and the color unevenness can be homogenized.

[0099] FIG. 34 is a diagram showing an example of the light quantity distribution of a screen projection image projected onto a screen by the projector according to the first embodiment. FIG. 35 is a timing chart for one cycle of the input current amount to the laser light source in each divided region of the LD light source in the projector according to the first embodiment. In the present embodiment, as shown in FIG. 35, the light source unit control means 130 reduces the input current amounts of the divided regions R1 and R4 during the blue period. Therefore, the light quantity distribution of the fluorescent light does not change. The light quantity distribution of the screen projection image shown in FIG. 34 has a peak at the center and the luminance decreases as it approaches the peripheral part. That is, the light quantity distribution of the screen projection image shown in FIG. 34 can obtain a shape having the same characteristics as the light quantity distribution of the fluorescent light shown in FIG. 32, and color unevenness on the screen SC can be further reduced by changing the LD output between the divided regions R1 to R4 of the LD light source Md. Note that the LD output between the divided regions R1 to R4 of the LD light source Md may be changed at the timing of irradiating the fluorescent light. For example, when the wiring connected to the divided region R1 of the LD light source Md is disconnected and the LD in the region L1 stops emitting light, the light source unit control means 130 can make the light quantity distribution of the fluorescent light uniform by increasing the LD output of the divided region R2 above the LD outputs of the divided regions R3 and R4 even during the light emission period T2 of the fluorescent light.

[0100] In the present embodiment, although the description is omitted, as shown in FIG. 22, when the light quantity distribution of the fluorescent light on the screen SC has a light quantity distribution in which the illuminance at the center is high and the peripheral part in the horizontal direction is low, at the timing when the blue excitation light is irradiated on the wavelength conversion region of the phosphor wheel 206, that is, at the timing when the fluorescent light is emitted from the phosphor wheel 206, by increasing the LD output (for example, the LD outputs of the divided regions R1 and R4), the luminance unevenness of the peripheral part in the horizontal direction of the screen SC can be improved like the light quantity distribution shown in FIG. 21.

[0101] FIG. 36 is a diagram showing an example in which screen projection images of projectors of the same model are superimposed by multi-projection. When superimposing screen projection images of the same model projector 101 by multi-projection, luminance unevenness and color unevenness may occur in the entire superimposed screen projection image due to differences in the projectors 101. The screen projection images shown in FIG. 36 are an example in which screen projection images are projected onto the screen SC by the same two projectors 101. However, the screen projection image on the left side is projected darkly, and although there is no color unevenness in the entire screen projection image, luminance unevenness occurs. The factors causing the luminance unevenness include individual differences in the LD light source Md and aging deterioration of the projection lens. For luminance unevenness due to superimposed use, it is advisable to adjust the brightness of the projector 101 that can be projected brightly to match the darker one. The reason is that if we try to adjust the darker projector 101 to match the brighter one, the power consumption will increase, and there is a possibility that the internal temperature of the projector will exceed the specified temperature and the lifespan will be shortened. To darken the brighter projector 101, it is advisable to proportionally reduce the overall LD output. That is, for example, during the yellow period, red period, blue period, and green period of the LD output in the time chart of the input current amounts for the divided regions R1 to R4 in the projector 101, each should be decreased at the same ratio.

[0102] FIG. 37 is a diagram showing another example in which screen projection images of projectors of the same model are superimposed by multi-projection. As shown in FIG. 37, when there is color unevenness such that the upper left of the screen projection image projected by the left projector 101 onto the screen SC becomes dark, for example, when the light quantity distribution on the left side of the screen projection image corresponds to the divided region R1 as in the time chart shown in FIG. 35, the color unevenness can be improved by reducing the LD output during the blue period of the divided region R1 more than that of the other divided regions R2 to R4.

[0103] As described above, according to the projector 101 according to the first embodiment, without adjusting the light quantity distribution by optical design, the light quantity distribution can be adjusted by controlling the LD output of the divided region R. Therefore, it is possible to reduce luminance unevenness and color unevenness without increasing the size of the projection device.

[0104] (Second Embodiment) This embodiment is an example of LD control when the phosphor wheel includes an excitation light reflection region (mirror) and two or more phosphor regions (wavelength conversion regions). In the following description, the description of the same configuration as that of the first embodiment will be omitted.

[0105] FIG. 38 is a diagram showing an example of the configuration of the phosphor wheel included in the projector according to the second embodiment. FIG. 39 is a timing chart for one cycle of the input current amount for each divided region of the LD light source in the projector according to the second embodiment. In this embodiment, as shown in FIG. 38, the phosphor wheel 206 includes an excitation light reflection region 206b and a plurality of phosphor regions 206a (first phosphor region 206a1, second phosphor region 206a2). That is, in this embodiment, the phosphor wheel 206 includes two or more phosphor layers (first phosphor region 206a1, second phosphor region 206a2). When the divergence angles of the fluorescent lights of the plurality of phosphor regions 206a are different from each other, the light amount distributions of the projected images (screen projected images) fluoresced for each phosphor region 206a are different. Therefore, the LD output between the divided regions R1 to R4 of the LD light source Md incident on each phosphor region 206a may be changed.

[0106] For example, the first phosphor region 206a1 emits yellow fluorescent light, and the second phosphor region 206a2 emits green fluorescent light. In this case, the yellow fluorescent light emitted from the first phosphor region 206a1 passes through the yellow region Y and the red region R of the color wheel 208. Therefore, by changing the LD output during the yellow period corresponding to the yellow region Y, the light amount distribution of the screen projected image of the first phosphor region 206a1 is changed (generated). Similarly, the green fluorescent light emitted from the second phosphor region 206a2 also passes through the red region R of the color wheel 208. Therefore, by changing the LD output during the red period corresponding to the red region R, the screen projected image of the second phosphor region 206a2 is changed (generated). The blue excitation light reflected by the excitation light reflection region 206b forms the light amount distribution of the blue excitation light on the screen projected image after passing through the diffusion region.

[0107] From the above, when synthesizing (changing) the light quantity distribution of the screen projection images of the first phosphor region 206a1, the second phosphor region 206a2, and the excitation light reflection region 206b, the LD output between the divided regions R1 to R4 is changed so that color unevenness does not occur in the screen projection image. When the fluorescent light emitted from one phosphor region 206a passes through a plurality of regions of the color wheel 208, for example, when the first phosphor region 206a1 passes through the yellow region Y and the red region R of the color wheel 208, it is desirable to change the LD output between the divided regions R1 to R4 at the same magnification. The reason is that the shapes of the light quantity distributions of the screen projection images passing through the yellow region Y and the red region R of the color wheel 208 are approximately the same because they are the light quantity distributions of the fluorescent light emitted from the same phosphor region 206a. If the LD output is not changed at the same magnification, an illuminance difference will occur and color unevenness will result.

[0108] FIG. 40 and FIG. 41 are diagrams showing an example of the horizontal light quantity distribution of the central portion of the screen projection image projected by the projector according to the second embodiment. Here, for example, an example of a method of adjusting (changing) the LD output between the divided regions R1 to R4 of the LD light source Md is described so that the light quantity distributions of the yellow fluorescent light, the green fluorescent light, and the blue excitation light in the horizontal direction of the central portion of the screen projection image projected by the projector 101 according to the present embodiment become the target light quantity distribution (hereinafter referred to as the target distribution). For example, when approximating the light quantity distribution of the screen projection image to the target distribution by reducing the LD output of the divided region R1 of the fluorescent light emitted from the first phosphor region 206a1 by 50%, the LD output of the divided region R1 in the yellow period and the red period is reduced by 50%. Similarly, when approximating the light quantity distribution of the screen projection image to the target distribution by reducing the LD output of the divided region R4 of the fluorescent light emitted from the second phosphor region 206a2 by 60%, the LD output of the divided region R4 is reduced by 60% only in the green period.

[0109] Here, for the sake of illustration, the light quantity distributions of yellow fluorescent light and green fluorescent light were adjusted by changing the LD outputs among the divided regions R1 to R4 of the LD light source Md. However, the target distribution can be arbitrarily determined. For example, as shown in FIG. 41, a target distribution approximated to the light quantity distribution of green fluorescent light can be set, and the LD outputs among the divided regions R1 to R4 of the LD light source Md can be changed so that the light quantity distribution of fluorescent light approximates the light quantity distribution of blue excitation light.

[0110] Also, there is a limit to the input current values input to each of the divided regions R1 to R4 of the LD light source Md. For example, there is an allowable current value that does not reach the temperature at which the lens or the phosphor region 206a of the phosphor wheel 206 burns. Therefore, it is preferable to change the LD outputs among the divided regions R1 to R4 of the LD light source Md so that the average current amount of the input current amount with respect to the lighting time of the LD light source Md is equal to or less than the allowable current amount. Instead of the input current value, the LD outputs among the divided regions R1 to R4 may be changed by power consumption, and it is preferable not to accelerate the deterioration of the lens or the phosphor wheel 206.

[0111] Thus, according to the projector 101 according to the second embodiment, the same operational effects as those of the first embodiment can be obtained.

[0112] (Third Embodiment) This embodiment is an example in which the optical system other than the light tunnel of the light source device is arranged so that the excitation light on the side surface in the long side direction of the opening surface of the light tunnel is irradiated. In the following description, the description of the same configuration as that of the above-described embodiment will be omitted.

[0113] Figures 42 and 43 are diagrams showing an example of the positional relationship between the optical system other than the light tunnel included in the light source optical system of the projector according to the third embodiment and the light tunnel. In the present embodiment, the optical system other than the light tunnel LT included in the light source device (light source optical system) 102 is arranged such that blue excitation light is irradiated onto the side surface of the long side (LE = 5.7 mm) of the opening surface of the light tunnel LT, as shown in FIG. 42. In this case, the optical system other than the light tunnel LT included in the light source device 102 has a Y-axis in the vertical direction (the direction corresponding to the long side direction LE of the light tunnel LT), an X-axis in the horizontal direction corresponding to the depth direction of the light tunnel LT, and a Z-axis in the horizontal direction corresponding to the short side direction SE of the light tunnel LT.

[0114] Further, as shown in FIG. 43, the optical system other than the light tunnel LT of the light source device 102 can also be arranged such that blue excitation light is irradiated onto the side surface of the short side direction SE (= 3.4 mm) of the opening surface of the light tunnel LT. The optical system other than the light tunnel LT of the light source device 102 has a Z-axis in the vertical direction (the direction corresponding to the long side direction LE of the light tunnel LT), an X-axis in the horizontal direction corresponding to the depth direction of the light tunnel LT, and a Y-axis in the horizontal direction corresponding to the short side direction SE of the light tunnel LT.

[0115] However, when the excitation light is incident in the long side direction LE of the light tunnel LT, the number of reflections in the light tunnel LT increases compared to when it is incident in the short side direction SE, and it has a more uniform effect. The blue excitation light is incident on the light incident on the condenser lens 207 at a position where the image of the laser light source 201 is formed, and when the image is viewed from the short side SE side, the light rays are emitted at an angle of 0 < θ < 90 [deg]. That is, in the light source device 102 shown in FIG. 42, the light rays are emitted in the Z-axis direction at an angle of 0 < θ < 90 [deg]. Also, in the light source device 102 shown in FIG. 43, the light rays are emitted in the Y-axis direction at an angle of 0 < θ < 90 [deg]. The light emitted from the condenser lens 207 passes through the diffusion region of the color wheel 208 and then enters the light tunnel LT. Since the exit surface of the condenser lens 207 and the entrance surface of the light tunnel LT are parallel, the angle of the incident light with respect to the opening surface of the light tunnel LT has a vertical angle to the exit angle of the condenser lens 207. The distance until the light rays incident on the light tunnel LT are reflected by the end face in the light tunnel LT and then reflected by the opposite end face is, in the case of the light source device 102 shown in FIG. 42, the short side direction SE / tanθ [mm], and in the case of the light source device 102 shown in FIG. 43, the long side direction LE / tanθ [mm], and short side direction SE / tanθ < long side direction LE / tanθ. Therefore, as shown in FIG. 42, when the light rays are incident in the long side direction LE (Z-axis direction) of the opening surface of the light tunnel LT, compared to when they are incident in the short side direction SE (Y-axis direction) of the opening surface of the light tunnel LT as shown in FIG. 43, the number of reflections in the light tunnel LT increases, and the light uniformity effect becomes higher.

[0116] Also, in the case of the light source device 102 shown in FIG. 42, since the light homogenization effect by the light tunnel LT increases in the short side direction SE of the light tunnel LT, the light quantity distribution on the projection surface of the screen conjugate with the exit surface of the light tunnel LT can reduce color unevenness and luminance unevenness in the short side direction SE of the light tunnel LT, that is, in the vertical direction which is the short side of the screen SC. From the above, since the light homogenization effect in the short side direction SE of the light tunnel LT can be enhanced by the light rays entering obliquely with respect to the long side direction LE of the light tunnel LT, color unevenness and luminance unevenness can be reduced. Further, by the optical system such as the condenser lens 207, the light from the LD light source Md is guided so as to cross the optical axis at a substantially conjugate position when viewed from the short side direction of the first image of the LD light source Md, the long side of the first image is aligned with the long side direction LE of the light tunnel LT, and the short side of the first image is aligned with the short side direction SE of the light tunnel LT. Then, by changing the LD output between the divided regions R1 to R4 obtained by dividing the arrangement region of the LD light source Md in the long side direction LE of the light tunnel LT to adjust the light quantity distribution of the fluorescent light, luminance unevenness can be reduced, and by adjusting the blue excitation light, color unevenness can be reduced. Therefore, the light homogenization effect in the long side direction LE of the light tunnel LT can be enhanced. Thus, in the present embodiment, since the light homogenization effects in the short side direction SE and the long side direction LE of the light tunnel LT can be enhanced, luminance unevenness and color unevenness of the screen projection image on the screen SC can be reduced.

[0117] FIG. 44 is a diagram showing an example of the arrangement relationship between the light source optical system and the illumination optical system in the projector according to the third embodiment. When the excitation light is incident in the short side direction SE of the light tunnel LT, since the light quantity distributions of the DMD of the illumination optical system 104 and the exit surface of the light tunnel LT have a conjugate relationship, it is necessary to rotate the light source device 102 and the heat sink from the horizontal direction to the vertical direction with the light tunnel LT as the center. Therefore, since the long side direction when the light source device 102 and the heat sink are regarded as a set is different from the long side direction when the illumination optical system and the projection optical system are regarded as a set, there is a problem that the entire projector 101 becomes large. When the excitation light is incident in the long side direction LE of the light tunnel LT, since the long side directions are substantially aligned, the projector 101 can be miniaturized.

[0118] Further, when the blue excitation light is incident in the long side direction LE of the opening surface of the light tunnel LT, the number of reflections in the light tunnel LT increases and the light is made more uniform than when it is incident in the short side direction SE. Since the fluorescent light becomes Lambertian light in the phosphor region 206a and is incident on the light tunnel LT, the light is already uniform, and the homogenization effect by the light tunnel LT is less than that of the blue excitation light.

[0119] Figs. 45 to 48 are diagrams showing an example of the light quantity distribution on the DMD in the projector according to the third embodiment. Fig. 45 is a diagram showing an example of the light quantity distribution of the blue excitation light on the DMD when the blue excitation light is incident in the long side direction LE of the light tunnel LT. Fig. 46 is a diagram showing an example of the light quantity distribution of the blue excitation light on the DMD when the LD light source Md is rotated by 90 degrees. Fig. 47 is a diagram showing an example of the light quantity distribution of the fluorescent light on the DMD when the fluorescent light is incident in the short side direction SE of the light tunnel LT. Fig. 48 is a diagram showing an example of the light quantity distribution of the fluorescent light when the LD light source Md is rotated by 90 degrees. Since the exit surface of the light tunnel LT and the image on the DMD are in a conjugate relationship, the long side direction LE of the light tunnel LT and the long side direction of the DMD, and the short side direction SE of the light tunnel LT and the short side direction of the DMD correspond to each other. In the light quantity distributions shown in Figs. 45 to 48, the higher the numerical value, the higher the luminance, and the lower the numerical value, the lower the luminance. The light quantity distribution of the blue excitation light shown in Fig. 46 varies greatly on the DMD due to the difference in the incident direction of the light rays to the light tunnel LT. On the other hand, the light quantity distribution of the fluorescent light shown in Fig. 48 does not change much compared to the light quantity distribution of the blue excitation light on the DMD. The reason is that the blue excitation light continues to be condensed by the condenser lens group until it passes through the diffusion plate in front of the light tunnel LT, while the fluorescent light emits Lambertian light in the wavelength conversion region (phosphor region 206a) of the phosphor wheel 206, so light rays with all incident angles enter the light tunnel LT, and the uniform effect by the light tunnel LT is small. And the condensed light rays of the blue excitation light can increase the number of reflections when the light rays are incident in the long side direction LE of the light tunnel LT, so the light uniformity is greatly improved. From the above, it can be seen that the incident surface of the LD light source Md to the light tunnel LT greatly contributes to light uniformity.

[0120] Thus, according to the projector 101 according to the third embodiment, by making the excitation light enter in the long side direction LE of the light tunnel LT, the number of reflections in the light tunnel LT can be increased more than when it enters in the short side direction SE, and the homogenization effect by the light tunnel LT can be improved. Therefore, the luminance unevenness and color unevenness of the screen projection image on the screen SC can be further reduced.

Explanation of Signs

[0121] 101 Projector 102 Light source device 104 Illumination optical system 105 Image forming element 106 Projection optical system 201 Laser light source 202 Collimator lens 203 First optical system 204 Dichroic mirror 205 Second optical system 206 Phosphor wheel 206a Phosphor region 206b Excitation light reflection region 207 Condensing lens 208 Color wheel LT Light tunnel SC Screen R1~R4 Division region Md LD light source

Prior Art Documents

Patent Documents

[0122]

Patent Document 1

Claims

1. A light source device including an arrangement region in which a plurality of light sources are arranged, the arrangement region being divided into one or more divided regions each including the light source, and the dividing directions of the divided regions in the arrangement region being substantially aligned; an optical system that forms a first image of the light source unit; a light homogenizing element having an aperture into which a light beam emitted from the optical system is incident in the vicinity of an image plane where the first image is formed; and comprising: The aperture is a substantially rectangular aperture having a long side and a short side in a cross section perpendicular to the traveling direction of the incident light beam; The optical system passes a light beam emitted from the light source through the vicinity of the optical axis of the optical system on the image plane where the first image is formed, and guides the light beam to irradiate the side surface of the long side of the aperture surface of the light homogenizing element across the optical axis; The arrangement region is rectangular, and the dividing direction is a direction corresponding to the long side direction of the aperture; A light source device that varies the light output of the light sources included in the respective divided regions in the dividing direction so as to be different from each other.

2. The optical system forms a second image of the light source unit on the optical path of the light beam between the light source and the first image; The light beam emitted from the light source unit passes through the vicinity of the optical axis in the vicinity of the image plane where the second image is formed. The light source device according to claim 1.

3. The light source device according to claim 1 or 2, wherein the longitudinal direction of the aperture and the arrangement direction of the images of the divided regions in the first image are aligned.

4. The light beam emitted from the optical system passes through the vicinity of the optical axis along the arrangement direction of the images of the divided regions on the image plane of the first image. The light source device according to claim 3.

5. The light source device according to any one of claims 1 to 4, further comprising a diffusion member that is disposed offset from the position of the image plane where the first image is formed and diffuses the light beam emitted from the optical system.

6. Further comprising a wavelength conversion unit that emits wavelength-converted light obtained by converting the wavelength of the light emitted from the light source, The wavelength conversion unit is disposed near the image plane where the second image is formed, The optical system forms an image of wavelength-converted light conjugate with the image of the light source formed on the wavelength conversion unit near the image plane where the first image is formed. The light source device according to claim 2.

7. The light source device according to claim 6, wherein the light output of the light source included in each divided region is changed so that the light quantity distribution of the wavelength-converted light becomes uniform at a desired irradiation position.

8. The light source device according to claim 6 or 7, wherein the light output of each divided region is changed so that the light quantity distribution of the light emitted from the light source unit matches the light quantity distribution of the wavelength-converted light at a desired irradiation position.

9. At the image plane where the first image is formed, the images of the respective light sources are substantially elliptical, The light source device according to any one of claims 1 to 4, wherein the longitudinal direction of the ellipse and the longitudinal direction of the opening of the light homogenizing element are aligned.

10. At the image plane where the first image of each light source is formed, the images of the respective light sources are substantially elliptical, The light source device according to any one of claims 1 to 4, wherein the short-axis direction of the ellipse and the longitudinal direction of the light homogenizing element are aligned.

11. The light source device according to any one of claims 1 to 4, An illumination optical system that forms an image of an emission part from which light is emitted from the light homogenizing element, An image forming element disposed at a position where the image of the emission part is formed, A projection optical system that forms an image of the image formed by the image forming element on a screen, And a projection device comprising the same.

Images