Light source device, image projection apparatus, and adjustment method

Abstract

To provide a light source device, an image projection apparatus, and an adjustment method capable of improving the utilization efficiency of light during a spoke time.SOLUTION: A light source device includes: a first light source module that includes a first light source and a first phosphor wheel having a plurality of regions that emit light source light with mutually different wavelengths from the light source light emitted by the first light source; a second light source module that includes a second light source and a second phosphor wheel having a plurality of regions that emit light source light with mutually different wavelengths from the light source light emitted by the second light source; and a color wheel having a plurality of filter regions. The color wheel is arranged such that a color spoke, which is a boundary portion between the plurality of filter regions, passes in the order from a first color side spot to a second color side spot, or from the second color side spot to the first color side spot.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a light source device, an image projection device, and an adjustment method. [Background technology]

[0002] A commonly known lighting technology involves rotating a disc-shaped color wheel with multiple filters, such as multiple dichroic filters, arranged around the circumference of a rotating body, to sequentially switch between the multiple filters and use the colors obtained by each filter as illumination. When using a color wheel, the borders (spokes) of the filters pass through a spot of light from a light source during the spoke time, during which adjacent filters with different transmission characteristics pass through the spot, resulting in color mixing. Because this spoke time cannot be eliminated, it is necessary to shorten the time required for color mixing.

[0003] As a technology using such a color wheel, a technology has been disclosed in which a phosphor wheel (wavelength conversion wheel) having a wavelength conversion region and a reflective region is rotated, and light source light is sequentially irradiated onto the wavelength conversion region and the reflective region, thereby using two light source units that generate the color of the light source light (e.g., blue) and a color in a wavelength band different from the light source light (e.g., yellow), in time sequence, and the timing of the rotation of the phosphor wheel of each light source unit is synchronized (e.g., Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the rotation timing of the phosphor wheels of the two light source units is synchronized, there is a problem in that the light utilization efficiency during spoke time decreases.

[0005] The present invention has been made in view of the above, and has an object to provide a light source device, an image projection device, and an adjustment method that can improve the light utilization efficiency in spoke times. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the present invention provides a first light source module including a first light source and a first phosphor wheel having a plurality of regions each emitting light source light of a wavelength different from that of the light source light emitted from the first light source, or a plurality of regions including a region emitting light source light emitted from the first light source and a region emitting light source light of a wavelength different from that of the light source light, and the first phosphor wheel rotating around a rotation axis at the center of a disk shape; a second light source module including a second light source and a second phosphor wheel having a plurality of regions each emitting light source light of a wavelength different from that of the light source light emitted from the second light source, or a plurality of regions including a region emitting light source light emitted from the second light source and a region emitting light source light of a wavelength different from that of the light source light; and a color wheel that includes a plurality of filter regions having different transmittances and rotates around the center of the disk shape as an axis of rotation, wherein first phosphor side spots are formed on the first phosphor wheel by light source light irradiated from the first light source, and second phosphor side spots are formed on the second phosphor wheel by light source light irradiated from the second light source, and first color side spots are formed on the color wheel by light source light generated by the first light source module and second color side spots are formed by light source light generated by the second light source module, and color spokes that are boundaries of the plurality of filter regions are arranged so that they pass from the first color side spot to the second color side spot or from the second color side spot to the first color side spot. [Effects of the Invention]

[0007] According to the present invention, it is possible to improve the light utilization efficiency in spoke time. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating the basic configuration of a light source device according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an example of the configuration of a phosphor wheel and a color wheel of the light source device according to the embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of the configuration of the image projection device according to the embodiment. [Figure 4] FIG. 4 is a diagram illustrating the optical path of fluorescent light in the image projection device according to the embodiment. [Figure 5] FIG. 5 is a diagram illustrating a spot of light source light incident on an incident surface of a light tunnel of a light source device according to an embodiment. [Figure 6] FIG. 6 is a diagram illustrating an example of a hardware configuration of the image projection device according to the embodiment. [Figure 7] FIG. 7 is a diagram illustrating the timing of spoke times of the phosphor wheel and the color wheel in the light source device according to the embodiment. [Figure 8] FIG. 8 is a diagram showing the positional relationship (time T1) between the phosphor wheel, the spokes of the color wheel, and the spot of the light source light in the light source device according to the embodiment. [Figure 9] FIG. 9 is a diagram showing the positional relationship (time T2) between the phosphor wheel, the spokes of the color wheel, and the spot of the light source light in the light source device according to the embodiment. [Figure 10] FIG. 10 is a diagram showing the positional relationship (time T3) between the phosphor wheel, the spokes of the color wheel, and the spot of the light source light in the light source device according to the embodiment. [Figure 11] FIG. 11 is a diagram showing the positional relationship (time T4) between the phosphor wheel, the spokes of the color wheel, and the spot of the light source light in the light source device according to the embodiment. [Figure 12] FIG. 12 is a diagram showing the positional relationship (time T5) between the phosphor wheel, the spokes of the color wheel, and the spot of the light source light in the light source device according to the embodiment. [Figure 13] FIG. 13 is a diagram illustrating a case where the timing at which the spokes of two phosphor wheels pass the spot is synchronized in the light source device according to the embodiment. [Figure 14] FIG. 14 is a diagram illustrating the time it takes for a spoke of a color wheel in a light source device according to an embodiment to pass between two spots. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of a light source device, an image projection device, and an adjustment method according to the present invention will be described in detail with reference to the drawings. Furthermore, the present invention is not limited to the following embodiments, and the components in the following embodiments include those that can be easily conceived by a person skilled in the art, those that are substantially the same, and those that are within the scope of what is called equivalents. Furthermore, various omissions, substitutions, modifications, and combinations of the components can be made without departing from the spirit of the following embodiments.

[0010] (Basic configuration of light source device) Fig. 1 is a diagram illustrating the basic configuration of a light source device according to an embodiment. Fig. 2 is a diagram illustrating an example of the configuration of a phosphor wheel and a color wheel of a light source device according to an embodiment. The basic configuration of a light source device 10 according to this embodiment will be described with reference to Figs. 1 and 2. Note that Fig. 1 illustrates the configuration of a basic unit in which light source light emitted from one light source LD enters a light tunnel LT, and the configuration of a light source device 10 according to this embodiment having two such basic unit configurations will be described later with reference to Fig. 3.

[0011] In FIG. 1, the light source device 10 includes a light source LD, lenses L1 and L2, a microlens array MLA, a dichroic mirror DM, lenses L3 and L4, a phosphor wheel PW, a lens L5, a color wheel CW, and a light tunnel LT.

[0012] The light source LD is a laser array light source arranged in an array and emitting, for example, blue excitation light. The light source LD is preferably, for example, a semiconductor laser light source in order to emit blue excitation light. The light source LD is preferably a blue laser light source whose excitation light has a peak between 440 and 465 nm. To increase the irradiation power, the light source LD uses multiple LDs (laser diodes) and emits light with a power of several tens to several hundred watts. The light source LD has a collimator lens array that focuses the light emitted from each LD into approximately parallel light, depending on the number of LDs in the LD array (e.g., 7 × 2, 7 × 4, etc.). Hereinafter, the light transmitted, reflected, or diffused by each subsequent optical system, originating from the excitation light emitted from the light source LD, may be collectively referred to as "light source light."

[0013] The lenses L1 and L2 are optical system components that converge the parallel light emitted from the light source LD, convert it into a thin beam, and guide it to the dichroic mirror DM.

[0014] The microlens array MLA is an optical system component that splits the light source light that has passed through lenses L1 and L2 into multiple beams and superimposes some or all of the split beams. This makes it possible to uniformize the irradiation density of the light source light that is incident on the phosphor wheel PW, which is located downstream of the light source light's optical path. Note that in FIG. 1, the microlens array MLA is located downstream of lens L2, but this is not limiting and it may be located, for example, between lenses L1 and L2.

[0015] The dichroic mirror DM is an optical system component that bends the light path by reflecting the light source light (blue light) emitted from the microlens array MLA and leads it to the lens L3.

[0016] Lenses L3 and L4 are optical system components that condense the light source light reflected by the dichroic mirror DM and guide it to the phosphor wheel PW.

[0017] The phosphor wheel PW is a disk-shaped optical component that reflects or wavelength-converts the source light (blue light) emitted from the lens L4 to light of another color. As shown in FIG. 2(a), the phosphor wheel PW is divided into a circular shape and includes a reflective region BAR that reflects the source light (blue light) emitted from the lens L4, a wavelength conversion region YAR in which a phosphor that wavelength-converts the source light to yellow light is formed, and a wavelength conversion region GAR in which a phosphor that wavelength-converts the source light to green light is formed. As shown in FIG. 2(a), the spot SP, which is the spot on the phosphor wheel PW where the source light converged by the lens L4 strikes the phosphor wheel PW, may be referred to as a "phosphor-side spot." Furthermore, the boundary between adjacent regions among the reflective region BAR, wavelength conversion region YAR, and wavelength conversion region GAR may be referred to as a "phosphor spoke." The reflective region BAR, wavelength conversion region GAR, and wavelength conversion region YAR are examples of the "multiple regions" in the present invention.

[0018] The phosphor wheel PW is rotated by a motor or the like by a phosphor wheel drive circuit 812 (described later), and the position of the phosphor-side spot formed by the light source light emitted from the lens L4 is controlled to switch sequentially between the reflection area BAR, the wavelength conversion area YAR, and the wavelength conversion area GAR in time sequence. For example, when the phosphor-side spot is located in the reflection area BAR, the reflection area BAR reflects the light source light and causes the blue light source light to enter the lens L4. When the phosphor-side spot is located in the wavelength conversion area YAR, the wavelength conversion area YAR wavelength-converts the light source light to yellow fluorescent light and causes the fluorescent light to enter the light source lighting target area L4. When the phosphor-side spot is located in the wavelength conversion area GAR, the wavelength conversion area GAR wavelength-converts the light source light to green fluorescent light and causes the fluorescent light to enter the light source lighting target area L4.

[0019] The fluorescent light wavelength-converted in wavelength conversion regions YAR and GAR is converted into approximately parallel light by lenses L4 and L3, and then part of it enters lens L5 directly, and part of it passes through dichroic mirror DM and then enters lens L5. Furthermore, the blue light source light irradiated toward reflection region BAR is reflected by reflection region BAR and turned back, then passes through lenses L4 and L3, passes near dichroic mirror DM, and enters lens L5.

[0020] The lens L5 is an optical system member that collects the light source light that has been reflected or wavelength-converted by the phosphor wheel PW and directs it to the color wheel CW.

[0021] The color wheel CW is a disk-shaped optical component that transmits the light source light emitted from the lens L5 through the filter regions of each color, causing the light source light of each color to enter the light tunnel LT in a time-sequential manner. As shown in FIG. 2(b), the color wheel CW is divided circumferentially into the following filter regions: a filter region BF that transmits the blue light source light reflected from the reflection region BAR of the phosphor wheel PW and emitted from the lens L5; a filter region YF that transmits the yellow light source light (fluorescent light) that has been wavelength-converted by the wavelength conversion region YAR of the phosphor wheel PW and emitted from the lens L5; a filter region RF that transmits the red light contained in the yellow light source light (fluorescent light); and a filter region GF that transmits the green light source light (fluorescent light) that has been wavelength-converted by the wavelength conversion region GAR of the phosphor wheel PW and emitted from the lens L5. The spot on the color wheel CW where the light source light focused by the lens L5 strikes the color wheel CW is sometimes referred to as the "color-side spot." Furthermore, the boundary portions between adjacent regions among the above-mentioned filter region BF, filter region YF, filter region RF, and filter region GF may be referred to as "color spokes" hereinafter.

[0022] The color wheel CW is rotated by a motor or the like by a color wheel drive circuit 813 (described later), and the position of the color side spot formed by the light source light emitted from the lens L5 is controlled to switch sequentially between filter areas BF, YF, RF, and GF in time. For example, when the color side spot is located in filter area BF, filter area BF transmits blue light source light and allows it to enter the light tunnel LT. When the color side spot is located in filter area YF, filter area YF transmits yellow light source light and allows it to enter the light tunnel LT. When the color side spot is located in filter area RF, filter area RF transmits red light source light and allows it to enter the light tunnel LT. When the color side spot is located in filter area GF, filter area GF transmits green light source light and allows it to enter the light tunnel LT.

[0023] The light tunnel LT is an optical system component that superimposes and homogenizes the light source light of each color that has passed through the color wheel CW by repeatedly total reflecting it at internal interfaces. The light tunnel LT has an entrance surface with an aspect ratio that is approximately the same as the aspect ratio of a digital micromirror device used in the image projection device 1 (described later) in which the light source device 10 is installed.

[0024] In the light source device 10 shown in FIG. 1, the timing at which the phosphor spokes of the phosphor wheel PW pass through the phosphor-side spot and the timing at which the color spokes of the color wheel CW pass through the color-side spot are synchronized. This minimizes the time required for color mixing. However, if there are multiple basic unit configurations in which light source light emitted from a single light source LD enters the light tunnel LT, as shown in FIG. 1, multiple color-side spots corresponding to each configuration are formed on the color wheel CW. In this case, if the layout of the light source device 10 can be freely designed, the conventional technology can be used as is by arranging the multiple color-side spots so that the color spokes pass through multiple color-side spots simultaneously. However, due to the need to reduce the size of the image projection device 1 or constraints on the layout of the light source device 10, it may not be necessary to arrange the color spokes so that they pass multiple color-side spots simultaneously, or it may be desirable to freely position the center of rotation of the color wheel CW. In this embodiment, a light source device 10 with high light utilization efficiency is realized even in such cases.

[0025] (Configuration of image projection device) Fig. 3 is a diagram showing an example of the configuration of an image projection device according to an embodiment. Fig. 4 is a diagram illustrating the optical path of fluorescent light in an image projection device according to an embodiment. Fig. 5 is a diagram illustrating the spot of light source light incident on the incident surface of the light tunnel of the light source device according to an embodiment. With reference to Figs. 3 to 5, the configuration of light source device 10 according to this embodiment, which has two basic unit structures where light source light emitted from light source LD enters light tunnel LT, and the configuration of image projection device 1 including light source device 10 will be described.

[0026] As shown in Fig. 3, the image projection device 1 according to this embodiment includes a light source device 10, an illumination optical system 11, a digital micromirror device DMD, and a projection lens 12 (projection optical system). Also, as shown in Fig. 3, the light source device 10 includes a light source module Mda (first light source module), a light source module Mdb (second light source module), a prism PR, a color wheel CW, and a light tunnel LT. The light source modules Mda and Mdb correspond to the configuration of the basic unit described above.

[0027] As shown in Fig. 3, the light source module Mda includes a light source LDa (first light source), lenses L1a and L2a, a microlens array MLAa, a dichroic mirror DMa, lenses L3a and L4a, a phosphor wheel PWa (first phosphor wheel), and a lens L5a. As shown in Fig. 3, the light source module Mdb includes a light source LDb (second light source), lenses L1b and L2b, a microlens array MLAb, a dichroic mirror DMb, lenses L3b and L4b, a phosphor wheel PWb (second phosphor wheel), and a lens L5b. The functions of light sources LDa and LDb, lenses L1a and L1b, lenses L2a and L2b, microlens arrays MLAa and MLAb, dichroic mirrors DMa and DMb, lenses L3a and L3b, lenses L4a and L4b, phosphor wheels PWa and PWb, and lenses L5a and L5b are similar to those of light source LD, lens L1, lens L2, microlens array MLA, dichroic mirror DM, lenses L3 and L4, phosphor wheel PW, and lens L5 shown in Figure 1. The function of color wheel CW is as described in Figure 1.

[0028] In addition, when referring to any particular component or collectively referring to light sources LDa, LDb, lenses L1a, L1b, lenses L2a, L2b, microlens arrays MLAa, MLAb, dichroic mirrors DMa, DMb, lenses L3a, L3b, lenses L4a, L4b, phosphor wheels PWa, PWb, and lenses L5a, L5b, they will be referred to simply as "lens L1," "lens L2," "microlens array MLA," "dichroic mirror DM," "lens L3," "lens L4," "phosphor wheel PW," and "lens L5," respectively.

[0029] The optical members constituting the light source modules Mda and Mdb are arranged on a plane parallel to the ZX plane (horizontal plane), and the light source modules Mda and Mdb are arranged on planes spaced a predetermined distance apart in the y direction.

[0030] The prism PR is an optical element that reflects the light source light emitted from the light source module Mdb (i.e., the light source light emitted from the lens L5b) and causes it to enter the light tunnel LT via the color wheel CW. As described above, the light source modules Mda and Mdb are arranged on planes spaced a predetermined distance apart in the y direction, and therefore the light source light emitted from the light source module Mda (i.e., the light source light emitted from the lens L5a) passes through the front side of the prism PR as viewed from the plane of FIG. 3 (without passing through the prism PR) and enters the light tunnel LT directly via the color wheel CW. Note that a plane mirror, for example, may be provided instead of the prism PR to reflect the light source light emitted from the light source module Mdb.

[0031] The light tunnel LT superimposes and homogenizes the light source light from the light source modules Mda and Mdb that has passed through the color wheel CW by repeatedly total reflecting it at internal interfaces. The light tunnel LT is made of a material with a refractive index, such as a glass material, and may be, for example, a glass rod that utilizes total reflection inside. The light source light emitted from the light source modules Mda and Mdb is most concentrated near the entrance surface of the light tunnel LT. As shown in FIG. 5, the entrance surface of the light tunnel LT is rectangular with a long side approximately in the y direction and a short side approximately in the x direction. Similarly, the exit surface of the light tunnel LT is rectangular with a long side approximately in the y direction and a short side approximately in the x direction. As shown in FIG. 5, the focusing points of the light source light from the light source modules Mda and Mdb that enter the entrance surface of the light tunnel LT are spaced apart from each other. In this case, the light tunnel LT is arranged so that the direction in which the focusing points are aligned approximately coincides with the long side direction of the entrance surface (i.e., approximately the y direction), as shown in FIG. 5. Furthermore, the light source light from the light source modules Mda and Mdb also passes through the color wheel CW, which is positioned immediately before the entrance surface of the light tunnel LT, forming two color spots on the color wheel CW. The aspect ratio of the entrance surface and exit surface of the light tunnel LT is approximately the same as the aspect ratio of the digital micromirror device DMD. It is sufficient that the aspect ratios of the exit surface of the light tunnel LT and the digital micromirror device DMD are approximately the same; the entrance surface and exit surface of the light tunnel LT do not necessarily have to have the same shape.

[0032] The illumination optical system 11 is an optical system unit for illuminating the digital micromirror device DMD with uniformed light from the light source emitted from the light tunnel LT.

[0033] The digital micromirror device DMD is a two-dimensional light modulator that converts light from a light source emitted from an illumination optical system 11 into image light containing an image using a large number of movable micromirrors. The image light converted by the digital micromirror device DMD is incident on a projection lens 12.

[0034] The projection lens 12 is an optical system member for projecting the image light converted by the digital micromirror device DMD onto a screen or the like.

[0035] 4 shows the optical paths of fluorescent light obtained by wavelength conversion of light source light incident on the wavelength conversion regions of the phosphor wheels PWa and PWb. The fluorescent light passes through lenses L4a and L3a and lenses L4b and L3b, respectively, and enters the light tunnel LT via the color wheel CW.

[0036] (Hardware configuration of image projection device) 6 is a diagram showing an example of the hardware configuration of the image projection device according to the embodiment, The hardware configuration of the image projection device 1 according to the present embodiment will be described with reference to FIG.

[0037] As shown in FIG. 6, the image projection device 1 includes a CPU (Central Processing Unit) 801, a ROM (Read Only Memory) 802, a RAM (Random Access Memory) 803, a media I / F 807, an operation unit 808, a power switch 809, a network I / F 811, a phosphor wheel driving circuit 812, a color wheel driving circuit 813, and a light source driving circuit 814.

[0038] The CPU 801 is a computing device that controls the overall operation of the image projection device 1. The ROM 802 is a non-volatile storage device that stores programs used to drive the CPU 801. The RAM 803 is a volatile storage device that is used as a work area for the CPU 801.

[0039] The media I / F 807 is an interface circuit that controls reading and writing (storing) of data from and to a recording medium 806 such as a flash memory.

[0040] The operation unit 808 is provided with various keys, buttons, LEDs (Light Emitting Diodes), etc., and is an input device used by the user to perform various operations other than turning on / off the power of the image projection device 1. For example, the operation unit 808 accepts instruction operations such as operations to adjust the size of the projection image, operations to adjust the color tone, operations to adjust the focus, operations to adjust the keystone, etc., and outputs the contents of the accepted operations to the CPU 801.

[0041] The power switch 809 is a switch for switching the power of the image projection device 1 on and off.

[0042] The bus 810 is an address bus, a data bus, etc. for electrically connecting the components such as the CPU 801 shown in FIG.

[0043] The network I / F 811 is an interface circuit for performing data communication using a network such as the Internet.

[0044] The phosphor wheel drive circuit 812 is a drive circuit for controlling the rotation of the phosphor wheel PW (phosphor wheels PWa, PWb) via a motor or the like.

[0045] The color wheel driving circuit 813 is a driving circuit for controlling the rotation of the color wheel CW via a motor or the like.

[0046] The light source drive circuit 814 is a drive circuit that controls the turning on and off of the light sources LD (light sources LDa and LDb) under the control of the CPU 801.

[0047] The digital micromirror device DMD is a device that converts light source light from the light source LD (light source light emitted from the illumination optical system 11) into image light by a spatial light modulation method using a large number of movable micromirrors (micromirrors) based on image data input from an external device connection I / F 818 or the like, and projects the image light onto a projection surface such as a screen through the projection lens 12. Note that a liquid crystal panel may be used instead of the digital micromirror device DMD.

[0048] The external device connection I / F 818 is an interface circuit to which an information processing device such as a PC (Personal Computer) is connected, for transmitting and receiving control signals and image data to and from the information processing device.

[0049] The fan drive circuit 819 is connected to the CPU 801 and the cooling fan 820 , and is a drive circuit that drives / stops the cooling fan 820 based on a control signal from the CPU 801 .

[0050] The cooling fan 820 is a fan that rotates to exhaust air from inside the image projection device 1 and cool the inside of the image projection device 1.

[0051] Furthermore, when power is supplied to the image projection device 1, the CPU 801 executes a control program pre-stored in the ROM 802, sends a control signal to the light source drive circuit 814 to turn on the light source LD, and sends a control signal to the fan drive circuit 819 to rotate the cooling fan 820 at a predetermined rated speed. When the supply of power from the power supply circuit begins, the digital micromirror device DMD enters an image displayable state, and power is supplied from the power supply circuit to various other components. When the power switch 809 is turned OFF, the image projection device 1 sends a power-off signal from the power switch 809 to the CPU 801. Upon detecting the power-off signal, the CPU 801 sends a control signal to the light source drive circuit 814 to turn off the light source LD. After a predetermined time has elapsed, the CPU 801 sends a control signal to the fan drive circuit 819 to stop the cooling fan 820, terminates the control process, and finally sends an instruction to the power supply circuit to stop the supply of power.

[0052] (Rotation of phosphor wheel and color wheel) FIG. 7 is a diagram illustrating the timing of spoke times of the phosphor wheel and color wheel in the light source device according to the embodiment. FIG. 8 is a diagram illustrating the positional relationship (time T1) between the spokes of the phosphor wheel and color wheel and the spot of light source light in the light source device according to the embodiment. FIG. 9 is a diagram illustrating the positional relationship (time T2) between the spokes of the phosphor wheel and color wheel and the spot of light source light in the light source device according to the embodiment. FIG. 10 is a diagram illustrating the positional relationship (time T3) between the spokes of the phosphor wheel and color wheel and the spot of light source light in the light source device according to the embodiment. FIG. 11 is a diagram illustrating the positional relationship (time T4) between the spokes of the phosphor wheel and color wheel and the spot of light source light in the light source device according to the embodiment. FIG. 12 is a diagram illustrating the positional relationship (time T5) between the spokes of the phosphor wheel and color wheel and the spot of light source light in the light source device according to the embodiment. FIG. 13 is a diagram illustrating a case where the timing at which two phosphor wheel spokes pass through spots in the light source device according to the embodiment is synchronized. FIG. 14 is a diagram illustrating the time at which a color wheel spoke passes between two spots in the light source device according to the embodiment. With reference to Figures 7 to 14, we will explain the timing at which the phosphor spokes of the phosphor wheel PW pass through the phosphor side spots and the timing at which the color spokes of the color wheel CW pass through the color side spots in the light source device 10 of this embodiment.

[0053] First, FIG. 7 illustrates a specific timing state for explaining the relationship between the positions of the color side spots on the color wheel CW of the light source device 10 according to this embodiment and the positions of the phosphor side spots on the phosphor wheels PWa and PWb. Specifically, as shown in FIG. 7(a), a phosphor side spot PSPa (first phosphor side spot) is formed by the light source light being reflected by the reflection area BARa of the phosphor wheel PWa. As shown in FIG. 7(c), a color side spot CSPa (first color side spot) is formed by the light source light being incident on the filter area BF of the color wheel CW. Also, as shown in FIG. 7(b), a phosphor side spot PSPb (second phosphor side spot) is formed by the light source light being irradiated on the wavelength conversion area GARb of the phosphor wheel PWb. As shown in FIG. 7(c), a color side spot CSPb (second color side spot) is formed by the light source light being incident on the filter area GF of the color wheel CW. Thus, in this embodiment, the color spokes are configured to sequentially pass through the multiple color side spots formed on the color wheel CW. When viewed from the positive direction of the x-axis in FIG. 4, the color wheel CW and phosphor wheel PWa rotate counterclockwise around the center of their disk shapes as shown in FIG. 7. The phosphor wheel PWb also rotates around the center of its disk shape as its axis of rotation, so as to have the same correspondence relationship in the rotational directions as the color wheel CW and phosphor wheel PWa. As shown in FIG. 7(a), in the phosphor wheel PWa, the boundary between the reflective area BARa and the wavelength conversion area GARa is designated as phosphor spoke PS1a, the boundary between the wavelength conversion area YARa and the reflective area BARa is designated as phosphor spoke PS2a, and the boundary between the wavelength conversion area GARa and the wavelength conversion area YARa is designated as phosphor spoke PS3a. Also, as shown in Figure 7(b), in the phosphor wheel PWb, the boundary between the reflective area BARb and the wavelength conversion area GARb is designated as phosphor spoke PS1b, the boundary between the wavelength conversion area YARb and the reflective area BARb is designated as phosphor spoke PS2b, and the boundary between the wavelength conversion area GARb and the wavelength conversion area YARb is designated as phosphor spoke PS3b.7(c), on color wheel CW, the boundary between filter region BF and filter region GF is designated as color spoke CS1, the boundary between filter region YF and filter region BF is designated as color spoke CS2, the boundary between filter region GF and filter region RF is designated as color spoke CS3, and the boundary between filter region RF and filter region YF is designated as color spoke CS4. The following description focuses on phosphor spoke PS1a of phosphor wheel PWa, phosphor spoke PS1b of phosphor wheel PWb, and color spoke CS1 of color wheel CW. In this case, phosphor spoke PS1a corresponds to the "first phosphor spoke" of the present invention, and phosphor spoke PS1b corresponds to the "second phosphor spoke" of the present invention.

[0054] As shown in FIG. 8(a), the time T1 is the time when the color spoke CS1 on the color wheel CW begins to pass through the color-side spot CSPa. At time T1, the phosphor spoke PS1a on the phosphor wheel PWa also begins to pass through the phosphor-side spot PSPa. At this time T1, the light source light, which has been wavelength-converted to green fluorescent light by the phosphor-side spot PSPa in the wavelength conversion region GARa of the phosphor wheel PWa, passes through the color-side spot CSPa in the filter region GF of the color wheel CW. Similarly, the light source light, which has been wavelength-converted to green fluorescent light by the phosphor-side spot PSPb in the wavelength conversion region GARb of the phosphor wheel PWb, passes through the color-side spot CSPb in the filter region GF of the color wheel CW. The graph in FIG. 8(b) shows the output of the light source light passing through the color wheel CW, which is the output of green light source light passing through the color-side spots CSPa and CSPb.

[0055] As shown in FIG. 9(a), the time T2 is when the color spoke CS1 on the color wheel CW passes near the center of the color-side spot CSPa. At time T2, the phosphor spoke PS1a on the phosphor wheel PWa also passes near the center of the phosphor-side spot PSPa. At this time T2, the light source light, wavelength-converted to green fluorescent light by the phosphor-side spot PSPb in the wavelength conversion region GARb of the phosphor wheel PWb, passes through the color-side spot CSPb in the filter region GF of the color wheel CW. Meanwhile, the phosphor-side spot PSPa is formed by the phosphor spoke PS1a on the phosphor wheel PWa, resulting in color mixing. Furthermore, the mixed light source light passes through the color spoke CS1 on the color wheel CW. Therefore, as shown in FIG. 9(b), the output of the green light source light passing through the color wheel CW decreases, and the output of the blue light source light increases because the mixed light source light contains blue.

[0056] As shown in FIG. 10(a), the time when the color spoke CS1 passes between the color-side spot CSPa and the color-side spot CSPb on the color wheel CW is T3. At time T3, the phosphor spoke PS1a on the phosphor wheel PWa finishes passing through the phosphor-side spot PSPa. At time T3, the phosphor spoke PS1b on the phosphor wheel PWb begins passing through the phosphor-side spot PSPb. At this time T3, the blue light source light reflected by the phosphor-side spot PSPa on the phosphor wheel PWa passes through the color-side spot CSPa on the filter region BF of the color wheel CW. The light source light, which has been wavelength-converted to green fluorescent light by the phosphor-side spot PSPb on the wavelength conversion region GARb of the phosphor wheel PWb, passes through the color-side spot CSPb on the filter region GF of the color wheel CW. Therefore, as shown in FIG. 10(b), the blue light source light and the green light source light passing through the color wheel CW have approximately the same output.

[0057] As shown in FIG. 11(a), the time T4 is when the color spoke CS1 on the color wheel CW passes near the center of the color-side spot CSPb. At time T4, the phosphor spoke PS1b on the phosphor wheel PWb also passes near the center of the phosphor-side spot PSPb. At this time T4, the blue light source light reflected by the phosphor-side spot PSPa on the reflection area BARa of the phosphor wheel PWa passes through the color-side spot CSPb on the filter area BF of the color wheel CW. Meanwhile, the phosphor-side spot PSPb is formed by the phosphor spoke PS1b on the phosphor wheel PWb, resulting in color mixing. Furthermore, the mixed light source light passes through the color spoke CS1 on the color wheel CW. Therefore, as shown in FIG. 11(b), the output of the green light source light passing through the color wheel CW decreases, and the output of the blue light source light increases because the mixed light source light contains blue.

[0058] As shown in FIG. 12(a), the time when the color spoke CS1 on the color wheel CW finishes passing through the color-side spot CSPb is designated as T5. Also, at time T5, the phosphor spoke PS1b on the phosphor wheel PWb finishes passing through the phosphor-side spot PSPb. At this time T5, the blue light source light reflected by the phosphor-side spot PSPa on the reflective area BARa of the phosphor wheel PWa passes through the color-side spot CSPa on the filter area BF of the color wheel CW. Similarly, the blue light source light reflected by the phosphor-side spot PSPb on the reflective area BARb of the phosphor wheel PWb passes through the color-side spot CSPb on the filter area BF of the color wheel CW. Therefore, as shown in FIG. 12(b), the output is blue light source light that has passed through the color-side spots CSPa and CSPb.

[0059] Here, if, for example, when the color spoke CS1 of the color wheel CW passes through the color-side spot CSPa, not only does the phosphor spoke PS1a of the phosphor wheel PWa pass through the phosphor-side spot PSPa, but the phosphor spoke PS1b of the phosphor wheel PWb also passes through the phosphor-side spot PSPb, the light utilization efficiency during the spoke time would be reduced. For example, in this rotational timing, FIG. 13 shows the state of the color spoke CS1 at time T3 on the color wheel CW shown in FIG. 10 above. As shown in FIG. 13(a), at this time, the blue light source light reflected by the phosphor-side spot PSPa of the phosphor wheel PWa passes through the color-side spot CSPa in the filter region BF of the color wheel CW. However, the blue light source light reflected by the phosphor-side spot PSPb of the phosphor wheel PWb is incident on the color-side spot CSPb of the filter region GF of the color wheel CW, significantly reducing the utilization efficiency of the light source light. As a result, as shown in Figure 13(b), although the blue light source light passing through the color-side spot CSPa of the filter region BF passes through the color wheel CW, almost none of the blue light source light incident on the color-side spot CSPb of the filter region GF passes through the color wheel CW, so the output of the green light source light passing through the color wheel CW is almost zero, significantly reducing the utilization efficiency of light.

[0060] 8 to 12, in light source device 10 according to the present embodiment, when color spoke CS1 of color wheel CW passes through color-side spot CSPa, phosphor spoke PS1a of phosphor wheel PWa passes through phosphor-side spot PSPa, and when color spoke CS1 of color wheel CW passes through color-side spot CSPb, phosphor spoke PS1b of phosphor wheel PWb passes through phosphor-side spot PSPb. This improves the light utilization efficiency during spoke time.

[0061] Furthermore, color spoke CS1 passes through color-side spot CSPa within the time it takes phosphor spoke PS1a to pass through phosphor-side spot PSPa. Furthermore, color spoke CS1 passes through color-side spot CSPb within the time it takes phosphor spoke PS1b to pass through phosphor-side spot PSPb. This minimizes light loss within the spoke time, resulting in a light source device 10 with improved overall efficiency.

[0062] Furthermore, on the color wheel CW, the color side spot CSPa formed by the light source light from the light source module Mda and the color side spot CSPb formed by the light source light from the light source module Mdb are formed with their centers spaced apart in the scanning direction of the color spokes CS1, as shown in FIG. 14 . That is, the center of the color side spot CSPa is offset from the center of the color side spot CSPb. In this case, the color wheel CW is positioned so that the color spokes CS1 pass through the color side spot CSPa first and then the color side spot CSPb. Therefore, there is a time difference between the time when the color spokes CS1 pass near the center of the color side spot CSPa and the time when they pass near the center of the color side spot CSPb. If this time difference is defined as the passing time Tw, the light utilization efficiency during the spoke time can be improved by matching the time difference between the time when the phosphor spokes PS1a of the phosphor wheel PWa pass the phosphor side spot PSPa and the time when the phosphor spokes PS1b of the phosphor wheel PWb pass the phosphor side spot PSPb to this passing time Tw.

[0063] Furthermore, to adjust the rotation timing of the color wheel CW and phosphor wheels PWa and PWb as described above, for example, adjustments can be made as follows. First, adjustments are made so that the phosphor spokes PS1a of the phosphor wheel PWa pass through the phosphor-side spot PSPa when the color spoke CS1 of the color wheel CW passes through the color-side spot CSPa. Then, adjustments are made so that the phosphor spokes PS1b of the phosphor wheel PWb pass through the phosphor-side spot PSPb when the color spoke CS1 of the color wheel CW passes through the color-side spot CSPb. Note that the adjustments of the phosphor wheel PWa and the phosphor wheel PWb may be reversed. Alternatively, adjustments can be made as follows. First, adjustments are made so that the phosphor spokes PS1a of the phosphor wheel PWa pass through the phosphor-side spot PSPa when the color spoke CS1 of the color wheel CW passes through the color-side spot CSPa. Then, assuming that the transit time Tw, which is the time difference between when the color spoke CS1 passes near the center of the color-side spot CSPa and when it passes near the center of the color-side spot CSPb, is known, adjustment is made so that the time difference between when the phosphor spoke PS1a of the phosphor wheel PWa passes near the phosphor-side spot PSPa and when the phosphor spoke PS1b of the phosphor wheel PWb passes near the phosphor-side spot PSPb is equal to the transit time Tw. Note that the adjustment of the phosphor wheel PWa and the adjustment of the phosphor wheel PWb may be reversed. By performing this adjustment method, a light source device 10 can be realized that can improve the light utilization efficiency during spoke time. Note that while the timing described above is based on time, time depends on the distance from the rotation center of each spot or the rotation speed of each wheel, which can be complicated to handle. Therefore, the adjustment reference may be defined as an angle with 360 degrees as one cycle.

[0064] 7 to 14, the color spoke CS1 passes through the color side spot CSPa and then the color side spot CSPb, but it may pass through the color side spot CSPb and then the color side spot CSPa. Also, in the explanation of Figures 7 to 14, the phosphor spoke PS1a of the phosphor wheel PWa, the phosphor spoke PS1b of the phosphor wheel PWb, and the color spoke CS1 of the color wheel CW have been focused on, but this is not limiting, and the same applies to the other spokes of the phosphor wheels PWa, PWb, and color wheel CW.

[0065] As described above, in the light source device 10 according to this embodiment, the light source module Mda includes the light source LDa and the phosphor wheel PWa, which has a plurality of regions for emitting light source light of a plurality of wavelengths different from one another from the light source light emitted from the light source LDa and rotates around the center of the disk shape as a rotation axis; the light source module Mdb includes the light source LDb and the phosphor wheel PWb, which has a plurality of regions for emitting light source light of a plurality of wavelengths different from one another from the light source light emitted from the light source LDb and rotates around the center of the disk shape as a rotation axis; the color wheel CW includes a plurality of filter regions having different transmittances from one another and rotates around the center of the disk shape as a rotation axis; On the PWa, a phosphor side spot PSPa is formed by light source light emitted from light source LDa. On the phosphor wheel PWb, a phosphor side spot PSPb is formed by light source light emitted from light source LDb. On the color wheel CW, a color side spot CSPa is formed by light source light generated by light source module Mda. A color side spot CSPb is formed by light source light generated by light source module Mdb. The color spokes CS1, which are the boundaries of the multiple filter regions, are arranged so that they pass from the color side spot CSPa to the color side spot CSPb, or from the color side spot CSPb to the color side spot CSPa. This improves light utilization efficiency during spoke time. Furthermore, because the color spokes CS1 can be arranged so that they pass from the color side spot CSPa to the color side spot CSPb, or from the color side spot CSPb to the color side spot CSPa, the center of rotation of the color wheel CW can be freely positioned while maintaining high light utilization efficiency, thereby realizing a compact image projection device 1. It also becomes possible to freely arrange the layout of the light source device 10, thereby realizing a compact image projection device 1 while maintaining high light utilization efficiency. Furthermore, although the light source LDa constituting the light source module Mda and the light source LDb constituting the light source module Mdb have been described as being configured as separate light sources, a configuration may also be adopted in which the light source light emitted from a single light source is split into multiple parts using a half mirror or polarizing beam splitter that transmits part of the light source light and reflects part of it, and the split light is then guided to the phosphor wheels PWa and PWb of the multiple light source modules Mda and Mdb, respectively.

[0066] In the above-described embodiments, when at least one of the functional units of the image projection device 1 is realized by executing a program, the program is provided by being pre-installed in a ROM or the like. In the above-described embodiments, the program executed by the image projection device 1 may be provided by being recorded in an installable or executable file format on a computer-readable recording medium such as a CD-ROM (Compact Disc Read Only Memory), a flexible disk (FD), a CD-R (Compact Disk-Recordable), or a DVD (Digital Versatile Disc). In the above-described embodiments, the program executed by the image projection device 1 may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. In the above-described embodiments, the program executed by the image projection device 1 may be provided or distributed via a network such as the Internet. In the above-described embodiments, the program executed by the image projection device 1 has a modular configuration including at least one of the functional units. In actual hardware, the CPU 801 reads and executes the program from the storage device (e.g., the ROM 802) described above, thereby loading and generating the functional units described above into a main storage device (RAM 803).

[0067] The aspects of the present invention are as follows. <1> a first light source module including a first light source; and a first phosphor wheel having a plurality of regions each emitting light source light of a wavelength different from the wavelength of the light source light emitted from the first light source, or a plurality of regions including a region emitting light source light emitted from the first light source and a region emitting light source light of a wavelength different from the light source light, the first phosphor wheel rotating around a center of a disk shape as a rotation axis; a second light source module including a second light source; and a second phosphor wheel having a plurality of regions each emitting light source light of a wavelength different from the wavelength of the light source light emitted from the second light source, or a plurality of regions including a region emitting light source light emitted from the second light source and a region emitting light source light of a wavelength different from the light source light, the second phosphor wheel rotating around a center of a disk shape as a rotation axis; a color wheel including a plurality of filter regions having different transmittances and rotating around a center of a disk shape as a rotation axis; Equipped with a first phosphor side spot is formed on the first phosphor wheel by light source light irradiated from the first light source; a second phosphor side spot is formed on the second phosphor wheel by light source light irradiated from the second light source; The color wheel is a first color spot is formed by the light source light generated by the first light source module; a second color spot is formed by the light source light generated by the second light source module; The light source device is arranged so that color spokes, which are the boundaries of the multiple filter regions, pass through in the order from the first color side spot to the second color side spot, or from the second color side spot to the first color side spot. <2> The center of the first color spot is shifted from the center of the second color spot. <1> 2. The light source device according to claim 1 . <3> When the color spokes pass through the first color-side spot, a first phosphor spoke, which is a boundary portion of the plurality of regions of the first phosphor wheel, passes through the first phosphor-side spot; When the color spoke passes through the second color-side spot, the second phosphor spoke, which is a boundary of the plurality of regions of the second phosphor wheel, passes through the second phosphor-side spot. <1> or <2> 2. The light source device according to claim 1 . <4> the time difference between when the color spoke passes through the center of the first color-side spot and when it passes through the center of the second color-side spot is equal to the time difference between when the first phosphor spoke passes through the first phosphor-side spot and when the second phosphor spoke passes through the second phosphor-side spot; <3> 2. The light source device according to claim 1 . <5> The color spoke passes through the first color side spot within the time it takes for the first phosphor spoke to pass through the first phosphor side spot. <3> 2. The light source device according to claim 1 . <6> The color spoke passes through the second color side spot within the time it takes for the second phosphor spoke to pass through the second phosphor side spot. <3> 2. The light source device according to claim 1 . <7> the first light source and the second light source emit blue light as the source light, The plurality of regions include a wavelength conversion region that converts the blue light into a wavelength longer than the wavelength of the blue light. <1> ~ <6> 10. The light source device according to claim 9, wherein: <8> The aforementioned <1> ~ <7> the light source device according to any one of the preceding claims, a light tunnel for homogenizing the light source light that has passed through the color wheel by making it incident on a rectangular entrance surface having long sides and short sides; Including, This is an image projection device in which the direction in which the convergence point of the light source light from the first light source module incident on the incident surface and the convergence point of the light source light from the second light source module are aligned coincides with the long side direction of the incident surface. <9> a two-dimensional light modulator that converts the light source light that has passed through the light tunnel into image light containing an image; a projection optical system that projects the image light converted by the two-dimensional light modulator; The above-mentioned <8> 2. The image projection device according to claim 1, wherein: <10> The aforementioned <3> ~ <6> 10. A method for adjusting the light source device according to claim 9, adjusting the first phosphor spoke of the first phosphor wheel to pass through the first phosphor side spot when the color spoke of the color wheel passes through the first color side spot; adjusting the second phosphor spokes of the second phosphor wheel so that the second phosphor spokes pass through the first phosphor side spot when the color spokes of the color wheel pass through the second color side spot; This is an adjustment method having the following. <11> The aforementioned <3> ~ <6> 10. A method for adjusting the light source device according to claim 9, adjusting the first phosphor spoke of the first phosphor wheel to pass through the first phosphor side spot when the color spoke of the color wheel passes through the first color side spot; a step of matching a time difference between when the first phosphor spoke of the first phosphor wheel passes over the first phosphor-side spot and when the second phosphor spoke of the second phosphor wheel passes over the second phosphor-side spot with a time difference between when the color spoke passes over the center of the first color-side spot and when it passes over the center of the second color-side spot; This is an adjustment method having the following. [Explanation of symbols]

[0068] 1. Image projection device 10 Light source device 11 Illumination optical system 12 Projection lens 801 CPU 802 ROM 803 RAM 806 Media 807 Media I / F 808 Operation section 809 Power Switch 810 Bus 811 Network I / F 812 Phosphor wheel drive circuit 813 Color wheel driver circuit 814 Light source driving circuit 818 External device connection I / F 819 Fan drive circuit 820 Cooling Fan BAR, BARa, BARb reflection area BF filter area CS1~CS4 color spokes CSPa, CSPb color side spots CW Color Wheel DM, DMa, DMb Dichroic Mirror DMD Digital Micromirror Device GAR, GARa, GARb wavelength conversion region GF Filter Area L1~L5 lenses L1a~L5a lenses L1b~L5b lenses LD, LDa, LDb light source LT Light Tunnel Mda, Mdb light source module MLA, MLAa, MLAb Microlens Array PR Prism PS1a, PS1b, PS2a, PS2b, PS3a, PS3b Phosphor Spokes PSPa, PSPb phosphor spot PW, PWa, PWb phosphor wheels RF Filter Area SP Spot YAR, YARa, YARb wavelength conversion region YF filter area [Prior art documents] [Patent documents]

[0069] [Patent Document 1] Japanese Patent Publication No. 2022-090609

Claims

1. a first light source module including: a first light source; and a first phosphor wheel having a plurality of regions each emitting light source light of a wavelength different from the wavelength of the light source light emitted from the first light source, or a plurality of regions including a region emitting the light source light emitted from the first light source and a region emitting light source light of a wavelength different from the light source light, the first phosphor wheel rotating around a center of a disk shape as a rotation axis; a second light source module including: a second light source; and a second phosphor wheel having a plurality of regions each emitting light source light of a wavelength different from the wavelength of the light source light emitted from the second light source, or a plurality of regions including a region emitting the light source light emitted from the second light source and a region emitting light source light of a wavelength different from the light source light, the second phosphor wheel rotating around a center of a disk shape as a rotation axis; a color wheel including a plurality of filter regions having different transmittances and rotating around a center of a disk shape as a rotation axis; Equipped with a first phosphor side spot is formed on the first phosphor wheel by light source light irradiated from the first light source; a second phosphor side spot is formed on the second phosphor wheel by light source light irradiated from the second light source; The color wheel is a first color spot is formed by the light source light generated by the first light source module; a second color spot is formed by the light source light generated by the second light source module; A light source device arranged so that color spokes, which are the boundaries of the multiple filter regions, pass through the first color side spot in the order from the first color side spot to the second color side spot, or from the second color side spot to the first color side spot.

2. 2. The light source device according to claim 1, wherein the center of the first color side spot is offset from the center of the second color side spot.

3. When the color spoke passes through the first color-side spot, a first phosphor spoke, which is a boundary portion of the plurality of regions of the first phosphor wheel, passes through the first phosphor-side spot; 3. The light source device according to claim 1, wherein when the color spoke passes through the second color side spot, the second phosphor spoke, which is the boundary between the plurality of regions of the second phosphor wheel, passes through the second phosphor side spot.

4. 4. The light source device of claim 3, wherein the time difference between when the color spoke passes through the center of the first color side spot and when it passes through the center of the second color side spot is the same as the time difference between when the first phosphor spoke passes through the first phosphor side spot and when the second phosphor spoke passes through the second phosphor side spot.

5. 4. The light source device of claim 3, wherein the color spokes pass through the first color-side spot within the time it takes the first phosphor spokes to pass through the first phosphor-side spot.

6. 4. The light source device according to claim 3, wherein the color spokes pass the second color-side spot within the time it takes the second phosphor spokes to pass the second phosphor-side spot.

7. the first light source and the second light source emit blue light as the source light, 3. The light source device according to claim 1, wherein the plurality of regions includes a wavelength conversion region that converts the blue light into a wavelength longer than the wavelength of the blue light.

8. The light source device according to claim 1 or 2; a light tunnel for homogenizing the light source light that has passed through the color wheel by making it incident on a rectangular entrance surface having long sides and short sides; Including, An image projection device in which the direction in which the convergence point of the light source light from the first light source module incident on the incident surface and the convergence point of the light source light from the second light source module are aligned coincides with the long side direction of the incident surface.

9. a two-dimensional light modulator that converts the light source light that has passed through the light tunnel into image light containing an image; a projection optical system that projects the image light converted by the two-dimensional light modulator; The image projection device according to claim 8 , comprising:

10. 4. A method for adjusting a light source device according to claim 3, adjusting the first phosphor spoke of the first phosphor wheel to pass through the first phosphor side spot when the color spoke of the color wheel passes through the first color side spot; adjusting the second phosphor spokes of the second phosphor wheel so that the second phosphor spokes pass through the first phosphor side spot when the color spokes of the color wheel pass through the second color side spot; The adjustment method has the following features.

11. 4. A method for adjusting a light source device according to claim 3, adjusting the first phosphor spoke of the first phosphor wheel to pass through the first phosphor side spot when the color spoke of the color wheel passes through the first color side spot; a step of matching a time difference between when the first phosphor spoke of the first phosphor wheel passes over the first phosphor-side spot and when the second phosphor spoke of the second phosphor wheel passes over the second phosphor-side spot with a time difference between when the color spoke passes over the center of the first color-side spot and when it passes over the center of the second color-side spot; The adjustment method has the following features.

Images