Color wheel, light source device and projection device

Abstract

To provide a color wheel excellent in color development, while enhancing a color purity of an original color.SOLUTION: A color wheel includes a first filter group / second filter group with a plurality of color filters respectively having different light permeation characteristics aligned therein. The first filter group and the second filter group are arranged so that the plurality of color filters in respective groups are aligned in a circumferential direction. The first filter group and the second filter group are arranged to form at least one location where color filters having same or similar light permeation characteristics are adjacent, from among the plurality of color filters. Respective areas or center angles for different colors are set nonuniform in the plurality of color filters respectively arranged in the first filter group and the second filter group. An area ratio or an angle ratio of the center angles of respective colors in the plurality of color filters composing the first filter group is substantially equal to an area ratio or an angle ratio of the center angles of respective colors in the plurality of color filters composing the second filter group.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a color wheel, and a light source device and a projection device equipped with the color wheel. [Background technology]

[0002] Projectors using the Digital Light Processing method already use a technology in which a color wheel equipped with circular color filters with various transmittance characteristics is rotated, and light is passed through the color wheel to output light of each color, such as red, blue, green, and yellow, in a time-division manner (see, for example, Patent Documents 1 to 4). When using a color wheel, the wheel is generally rotated continuously, generating one frame per revolution. The period when light is incident simultaneously across different adjacent color filters on the color wheel is called spoke time, and the colors of the multiple color filters mix, reducing the color purity of the light and making it impossible to treat it as pure color light. An increase in spoke time can lead to a deterioration in color performance due to a decrease in color purity, or a decrease in projector brightness due to the inability to use colored light in that area, so it is desirable to minimize this as much as possible.

[0003] In image projection devices using such a color wheel, a method is known in which the number of divisions (number of segments) of the color filter of the color wheel is doubled to generate two frames per rotation, with the aim of improving the frame rate and image quality by achieving pseudo-4K. However, doubling the number of segments on the color wheel simply doubles the spoke time.

[0004] In addition, to ensure the brightness of the projector, a configuration is also known in which two laser light sources and two phosphor modules are combined to use as illumination light. In this configuration, two spots are aligned on the color wheel, which raises concerns that the spoke time may become even longer. Furthermore, even with a conventional single light source system, there was a concern that the spoke time would increase if the diameter of the spot on the color wheel increased, particularly if the spot extended in the spoke scanning direction. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made to solve the above problems, and has as its object to provide a color wheel that increases the number of color filter segments while reducing the spoke time and improving color purity. [Means for solving the problem]

[0006] The color wheel of the present invention includes a first filter group in which a plurality of color filters having different light transmission characteristics are arranged, and a second filter group in which a plurality of color filters having different light transmission characteristics are arranged, and the first filter group and the second filter group are arranged so that the plurality of color filters of the first filter group and the plurality of color filters of the second filter group are lined up in the circumferential direction, and the first filter group and the second filter group are arranged so that, of the plurality of color filters arranged in each, color filters having the same or similar light transmission characteristics are adjacent to each other in at least one location, and the areas or central angles of the different colors of the plurality of color filters arranged in each of the first filter group and the second filter group are set unevenly, and the area ratio of each color or the angular ratio of the central angles of the plurality of color filters that make up the first filter group is approximately equal to the area ratio of each color or the angular ratio of the central angles of the plurality of color filters that make up the second filter group. [Effects of the Invention]

[0007] According to the present invention, it is possible to increase the number of segments of a color filter while reducing the spoke time and improving color purity. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing an example of the configuration of an image projection device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing an example of the configuration of a control unit of the image projection device. [Figure 3] 1 is a schematic diagram of a light source device to which an embodiment of the present invention can be applied. [Figure 4] FIG. 4 is a diagram illustrating an example of the configuration of a wavelength conversion element illustrated in FIG. [Figure 5] 4 is a diagram illustrating an example of a segment configuration of the color wheel illustrated in FIG. 3. FIG. [Figure 6] FIG. 1 is a diagram showing a comparative example of a segment configuration of a conventional color wheel. [Figure 7] FIG. 1 is a schematic diagram illustrating the concept of spoke times in a color wheel. [Figure 8] FIG. 6 is a diagram showing a first modified example of FIG. 5. [Figure 9] FIG. 6 is a diagram showing a second modified example of the configuration of the segments of the color wheel shown in FIG. [Figure 10] FIG. 6 is a diagram showing a third modified example of the configuration of the segments of the color wheel shown in FIG. [Figure 11] FIG. 7 is a diagram showing a fourth modified example of the configuration of the segments of the color wheel shown in FIG. [Figure 12] FIG. 1 is a diagram showing an example of a configuration to which the present invention is applied in a light source device having two light sources. [Figure 13] 13 is a diagram showing an example of transmitted light in the color wheel shown in FIG. 12. FIG. [Figure 14] FIG. 10 is a diagram showing an example in which two incident lights are arranged along the radial direction of a color wheel. [Figure 15]1 is a schematic diagram showing the optical axis for illustrating the incident position of transmitted light and the resulting effect in the present invention. FIG. [Figure 16] 16 is a schematic diagram showing an example of the positional relationship between the incident position of the transmitted light in FIG. 15 and the color wheel. FIG. [Figure 17] FIG. 1 is a diagram showing the relationship between the effective period and the central angle in a conventional color wheel. [Figure 18] FIG. 18 is a diagram showing a comparative example in which the number of plates in the configuration shown in FIG. 17 is simply increased to eight. [Figure 19] FIG. 1 is a diagram showing an example of the arrangement of segments in a color wheel of the present invention. [Figure 20] FIG. 20 is a diagram illustrating an example of rotation and validity period of the configuration illustrated in FIG. 19. [Figure 21] FIG. 10 is a diagram showing an example of a method for calculating a spot diameter in the present invention. [Figure 22] FIG. 10 is an enlarged view showing an example of the configuration of the spot diameter. [Figure 23] 10A and 10B are diagrams illustrating an example of a method for calculating the shape of a spot diameter based on light intensity in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] FIG. 1 is a diagram showing an example of the configuration of an image projection device 100 including a light source device 10 according to a first embodiment of the present invention. The image projection device 100 includes a light source device 10 serving as an illumination device, a DMD (Digital Micromirror Device) 101 serving as a spatial light modulator that modulates the illumination light generated by the light source device 10, an illumination optical system 102 that illuminates the light output from the light source device 10 approximately uniformly and directs it to the DMD 101, and a projection optical system 103 that enlarges and projects the light spatially modulated by the DMD 101 onto a projection surface 104. With this configuration, the image projection device 100 generates a projection image on the projection surface 104 .

[0010] The DMD 101 is a two-dimensional optical modulator that adds image information to the light beam emitted from the light source device 10 by reflecting the incident light beam with micromirrors arranged on the surface. In this embodiment, the DMD 101 is used as the two-dimensional optical modulator, but other types such as a transmissive liquid crystal element or a reflective liquid crystal element may also be used.

[0011] The projection optical system 103 is located downstream of the DMD 101 in the optical path, and is an optical system for projecting light onto a projection surface 104, which is a screen. The illumination optical system 102 is an optical system for guiding illumination light from the light source device 10 toward the DMD 101. These optical systems are composed of optical elements including lenses and mirrors, and are built into the housing 105 of the image projection device 100.

[0012] 2 is a hardware configuration diagram of a control unit of the image projection device 100. The image projection device 100 includes a CPU (Central Processing Unit) 801, a ROM (Read Only Memory) 802, a RAM (Random Access Memory) 803, a media I / F (Interface) 807, an operation unit 808, a power switch 809, a bus line 810, a network I / F 811, an LD (Laser Diode) drive circuit 814, a light source 11, a projection device 816, a projection lens 817, an external device connection I / F (Interface) 818, a fan drive circuit 819, and a cooling fan 820. Of these, the CPU 801 controls the overall operation of the image projection device 100. The ROM 802 stores programs used to drive the CPU 801. The RAM 803 is used as a work area for the CPU 801. A media I / F 807 controls reading and writing (storing) of data from and to a recording medium 806 such as a flash memory. The operation unit 808 is provided with various keys, buttons, LEDs, etc., and is used by the user to perform various operations other than turning on / off the power of the image projection device 100. 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. The power switch 809 is a switch for switching the power of the image projection device 100 on and off. The bus line 810 is an address bus, a data bus, or the like for electrically connecting the components such as the CPU 801. The network I / F 811 is an interface for performing data communication using a communication network such as the Internet. The LD drive circuit 814 controls the turning on and off of the light source 11 under the control of the CPU 801 . When light source 11 is turned on under the control of LD drive circuit 814, it irradiates projection light onto projection device 816. Light source 11 includes a light emitting element such as a laser diode (LD) module or an LED (Light Emitting Diode) module, and a solid light source element, and forms a light source unit. The projection device 816 is a control driver that operates the DMD 101 by spatial light modulation based on image data provided via an external device connection I / F 818, etc. The LD drive circuit 814, light source 11, projection device 816, and projection lens 817 function as a whole as a projection unit (projection means) that projects a projection image onto a projection surface based on image data. The external device connection I / F 818 is directly connected to a PC (Personal Computer) and receives control signals and image data from and to the PC. The fan drive circuit 819 is connected to the CPU 801 and the cooling fan 820 , and drives / stops the cooling fan 820 based on a control signal from the CPU 801 . The cooling fan 820 rotates to exhaust air from inside the image projection device 100 and cool the inside of the image projection device 100 . Furthermore, when power is supplied from the power supply, the CPU 801 starts up according to a control program pre-stored in the ROM 802, sends a control signal to the LD drive circuit 814 to turn on the light source 11, and sends a control signal to the fan drive circuit 819 to rotate the cooling fan 820 at a predetermined rated rotation speed. Furthermore, when the supply of power from the power supply circuit begins, the image projection device 100 puts the projection device 816 into a state where it can display an image, and furthermore, power is supplied from the power supply circuit to various other components. Furthermore, when the power switch 809 of the image projection device 100 is turned off, the power switch 809 sends a power-off signal to the CPU 801, and when the CPU 801 detects the power-off signal, it sends a control signal to the LD drive circuit 814 to turn off the light source 11. After a predetermined time has elapsed, the CPU 801 then sends a control signal to the fan drive circuit 819 to stop the cooling fan 820, and terminates its own control processing, and finally sends an instruction to the power supply circuit to stop the supply of power from the power source.

[0013] As shown in FIG. 3, light source device 10 functions as a lighting device that provides uniform illumination light by directing light as a light source module into light tunnel 3, which is a light uniformizing element. The light source device 10 includes a light source 11 as a laser light source that is a source of excitation light, a collimator lens array 12 arranged opposite the light source 11, a light source optical system 13, a focusing element 14, a dichroic mirror 15, a wavelength conversion element 17, a first focusing optical system 16, and a second focusing optical system 18. A light tunnel 3 is disposed at the end of the light source device 10, and functions as a light mixing element for homogenizing the light emitted from the light source 11 and outputting illumination light with a homogenized illuminance and light intensity distribution.

[0014] The light source 11 is a laser light source in this embodiment, and is a multi-chip laser diode unit in which a plurality of light-emitting sections 11A are arranged on a two-dimensional plane. A collimator lens array 12 is disposed at a position facing the light emitting unit 11A, and converts the excitation light emitted from the light emitting unit 11A into a parallel beam. The light source optical system 13 is a lens that condenses the excitation light that has been converted into parallel light by the collimator lens array 12 . Here, the center of the light source 11 generally coincides with the optical axis of the excitation light emitted from the light source 11. Therefore, the light source optical system 13 is provided so that the center of the light source and the optical axis of the light source optical system 13 are aligned. In this embodiment, the excitation light emitted by the light source 11 is preferably a blue laser light source having an emission oscillation wavelength of 440 nm to 465 nm.

[0015] The light-collecting element 14 is a lens disposed after the light source optical system 13 . Of the light beams transmitted through the condensing element 14, only light of a specific wavelength is reflected by the dichroic mirror 15, and an irradiation spot P1 is generated at a desired position on the wavelength conversion element 17 by the first condensing optical system 16. In other words, the wavelength conversion element 17 is provided near the irradiation spot P1. The irradiation spot P1 is an irradiation area having a certain range, and its position substantially coincides with the focal position of the first light collecting optical system 16.

[0016] The wavelength conversion element 17 is a disc-shaped phosphor wheel as shown in FIG. 4, and is attached to a drive motor to rotate at high speed, thereby moving the position of the irradiation spot P1 on the circumference of the wavelength conversion element 17 over time. In this embodiment, the wavelength conversion element 17 has a first phosphor region 32 coated with a yellow phosphor, an excitation light reflection region 33 that reflects excitation light, and a second phosphor region 34 coated with a green phosphor, and the position of the irradiation spot P1 is arranged to be located at either the first phosphor region 32, the second phosphor region 34, or the excitation light reflection region 33 by rotating the wavelength conversion element 17. Although an example in which the wavelength conversion element 17 is divided into three regions is shown here, the first phosphor region 32 and the second phosphor region 34 may be treated as one phosphor region, or may be divided into two or more regions as in this embodiment. Also, there may be multiple excitation light reflection regions 33 on the wavelength conversion element 17. With this configuration, when blue light having a central wavelength of 455 nm in luminous intensity is used as the excitation light emitted from the light source 11, the wavelength conversion element 17 outputs blue light when the irradiation spot P1 is located in the excitation light reflection region 33, outputs yellow fluorescence when the irradiation spot P1 is located in the first phosphor region 32, and outputs green fluorescence when the irradiation spot P1 is located in the second phosphor region 34. In this way, the wavelength conversion element 17 can irradiate light of a plurality of wavelengths in a time-division manner by rotating.

[0017] The light beam reflected by wavelength conversion element 17 passes through first focusing optical system 16 again and is focused by second focusing optical system 18, and then passes through color wheel 20 and enters light tunnel 3. In addition, because dichroic mirror 15 transmits fluorescence, the fluorescence irradiated onto first phosphor region 32 and second phosphor region 34 of wavelength conversion element 17 also passes through first focusing optical system 16 and second focusing optical system 18, passes through color wheel 20, and enters light tunnel 3. As shown in Figure 5, the color wheel 20 is a disk with an integrated filter divided into segments for the red region R, blue region B, green region G, and yellow region Y. It is an optical element that rotates while passing incident light F1 from the light source device 10 through it, converting the transmitted light into time-divided light of red, blue, green, and yellow. The blue region B corresponds to the excitation light reflection region 33 of the phosphor wheel, which is the wavelength conversion element 17 shown in Figure 4, and the yellow region Y, red region R, and green region G are synchronized to correspond to the phosphor regions 32 of the wavelength conversion element 17 shown in Figure 4, respectively. By placing a transmissive diffuser plate in the blue region B, it is possible to reduce the coherence of the light source 11 and reduce speckles on the projection surface 104. The yellow region Y and green region G transmit the wavelength regions of the yellow and green fluorescence emitted from the first phosphor region 32 and the second phosphor region 34, respectively. Furthermore, by using a dichroic mirror in the red region R, light in unnecessary wavelength regions from the wavelength of the yellow fluorescence L2 is reflected, thereby obtaining light of a highly pure color.

[0018] In light tunnel 3, the colored light with increased color purity is homogenized by being reflected and superimposed several times at internal interfaces. Furthermore, the opening of light tunnel 3 has an aspect ratio that is approximately the same as that of DMD 101, which is the image forming element, and the light emitted from the exit of light tunnel 3 is emitted as illumination light that is projected onto DMD 101 as shown in Figure 1. In this way, the light of each color generated over time by the wavelength conversion element 17 and the color wheel 20 is guided to the DMD 101 through the illumination optical system 102 to form an image corresponding to each color, which is then enlarged and projected onto the projection surface 104 by the projection optical system 103.

[0019] The color wheel 20 in this embodiment has a first filter group 21 in which segments of the red region R, yellow region Y, green region G, and blue region B are arranged in a fan shape within a semicircle, and a second filter group 22 in which segments of the red region R, yellow region Y, green region G, and blue region B are similarly arranged in a fan shape within a semicircle. The first filter group 21 is arranged in the order of R, Y, G, and B along the clockwise direction, which is the rotation direction 20r, when viewed from the incident side of the transmitted light. On the other hand, the second filter group 22 is arranged in the order of B, G, Y, and R along the rotation direction, which is the reverse order of the first filter group 21. Thus, in this embodiment, the color wheel 20 includes "a first filter group in which a plurality of color filters having different light transmission characteristics are arranged, and a second filter group in which a plurality of color filters having different light transmission characteristics are arranged." Furthermore, the plurality of color filters of the first filter group 21 and the plurality of color filters of the second filter group 22 are arranged so as to line up in the circumferential direction.

[0020] The reason for using the two filter groups, first filter group 21 and second filter group 22, will be explained below. In a conventional color wheel 300 such as that shown in FIG. 6, a method is known in which four colors obtained in one rotation in the order of B, Y, R, and G along the direction of rotation are used as primary colors to reproduce colors. When using a color wheel 300 such as that shown in Figure 6, one frame is generated per rotation, so if you want to speed up one frame to improve the frame rate or double the number of frames to artificially increase the resolution, you will need to increase the rotation speed. However, when the response speed of the DMD 101 and the wavelength conversion element 17, the durability and precision of the rotation drive unit, etc. are taken into consideration, there is a limit to simply increasing the rotation speed in this way.

[0021] On the other hand, in a configuration in which two filter groups corresponding to each color are provided as in this embodiment, it is possible to generate two frames of images by rotating the color wheel 20 once. In this way, by having multiple filter groups in the color wheel 20, the same number of frames as the filter groups can be generated per rotation, making it possible to double the number of frames without increasing the rotation speed. It should be noted that first filter group 21 and second filter group 22 each generate one frame with a half rotation.

[0022] That is, in this embodiment, the yellow region Y of the first filter group 21 and the yellow region Y of the second filter group 22 have the same area and the same central angle θY. A similar relationship holds for the green region G, the blue region B, and the red region R. In other words, in this embodiment, the color filters of the color wheel 20 are arranged symmetrically with respect to the line segment separating the first filter group 21 and the second filter group 22. In this way, the area ratio of each color or the angular ratio of the central angles of the multiple color filters that make up the first filter group 21 is set to be equal to the area ratio of each color or the angular ratio of the central angles of the multiple color filters that make up the second filter group 22. Here, the angle ratio being approximately equal means that if the difference between the central angle of a color filter in the first filter group 21 and the central angle of a color filter in the second filter group 22 is within ±5 degrees, then the angle ratio of those central angles can also be said to be approximately equal.

[0023] Incidentally, the illumination spot P2 on the color wheel has a finite size, more specifically, a size that is finite enough to fit within the size of the entrance of the light tunnel 3. In such an irradiation spot P2, the irradiation spot P2 may be located across a plurality of adjacent regions, for example, a yellow region Y and a green region G as shown in Fig. 7. This state is known as a spoke time. During spoke time, the light passing through the color wheel enters the light tunnel 3 with color components from both the yellow region Y and the green region G, which means that light with low color purity will be used if left as is. One possible solution is to avoid using light with such low color purity, but this would result in a decrease in light utilization efficiency by the amount of spoke time. Also, while it is possible to increase the output of light source 11 to ensure the illuminance of each color light, there is a problem in that the conversion efficiency of first phosphor region 32 and second phosphor region 34 using laser light has a fixed peak, and it is not possible to simply increase the light output.

[0024] Now, spoke time occurs where filters of different colors are adjacent, and it is preferable to keep it as small as possible. Naturally, when using multiple filter groups as in this embodiment, there is a concern that simply arranging multiple filter groups will double the spoke time.

[0025] Therefore, in this embodiment, with the aim of reducing such spoke time, the first filter group 21 and the second filter group 22 each have a plurality of color filters R, G, B, and Y arranged in a clockwise direction, which is the rotation direction, in the order of R, Y, G, and B. On the other hand, the second filter group 22 has filters B, G, Y, and R arranged in the rotation direction, which is the reverse order of the first filter group 21. With this configuration, at both ends of the first filter group 21 and the second filter group 22, the red region R of the first filter group 21 and the red region R of the second filter group 22, which are color filters with the same or similar light transmission characteristics, are adjacent to each other, and the blue region B of the first filter group 21 and the blue region B of the second filter group 22 are adjacent to each other, so an increase in spoke time is suppressed.

[0026] Furthermore, with this configuration, there will be some colors for which the spoke time can be reduced and some for which it cannot. For example, in this embodiment, since both the red region R and the blue region B have the effect of reducing the spoke time, the color purity may increase and the color intensity may become uneven. Alternatively, the uneven color intensity may also be caused by differences in the light emission characteristics or light intensity of the wavelength conversion element 17. Therefore, in this embodiment, as shown in FIG. 5, the areas or central angles of the different colors of the plurality of color filters arranged in each of the first filter group and the second filter group are set to be different. For example, in the diagram shown in FIG. 5, the area of ​​the yellow region Y of the first filter group 21 is different from the area of ​​the green region G of the first filter group 21, and similarly, the central angle θY is different from the central angle θG. This configuration can even out uneven color intensity caused by the arrangement of each filter on the color wheel 20, making it easier to ensure the illuminance of the illumination light emitted from the light source device 10 and also contributing to equalizing the illuminance.

[0027] As a first embodiment, a color wheel 20 arranged as shown in FIG. 5 has been described. However, the arrangement of the red region R, yellow region Y, green region G, and blue region B filters in the color wheel 20 is not limited to this configuration, and various modifications will be shown below.

[0028] FIG. 8 shows a modified example of the first embodiment, in which the wavelength characteristics of the red region R of the first filter group 21 and the red region R' of the second filter group 22 are different. It is preferable that the difference in wavelength characteristics be within a range that does not affect the color or gradation of the projected image. Specifically, when the cutoff wavelength of the red region R of the first filter group 21 is 600 nm, if the cutoff wavelength of the red region R' of the second filter group 22 is in the range of 600 nm ± 20 nm, it is possible to make the wavelength characteristics different between the red regions of the first filter group 21 and the second filter group 22 while still obtaining the effect of reducing the spoke time.

[0029] The color wheel 20 in the modified example of FIG. 9 is an example that is configured with only three colors, a red area R, a green area G, and a blue area B, in order to increase the hues of the primary colors and produce a vivid image. In this way, even when there are three or more segment regions due to the wavelength characteristics of the color wheel 20, it is possible to increase the number of segments of the color filter while reducing the spoke time and improving color purity.

[0030] Alternatively, as shown in the modified example of FIG. 10, more segment areas may be added to the color wheel 20, for example, a cyan area C and a magenta area M may be added. In this case, the segment areas of each filter in the first filter group 21 are formed in the rotational direction in the order of red region R, magenta region M, yellow region Y, green region G, cyan region C, and blue region B, and the segment areas of each filter in the second filter group 22 are similarly formed in the order of blue region B, cyan region C, green region G, yellow region Y, magenta region M, and red region R.

[0031] As shown in the modified example of FIG. 11, the blue region B and the green region G may be arranged in such an order that they are adjacent to each other.

[0032] As a second embodiment of this embodiment, an example in which light source device 10 is provided with light source units Md1 and Md2 as two light source modules will also be described. In the second embodiment, components common to the first embodiment will be assigned the same numbers and descriptions thereof will be omitted as appropriate. In this embodiment, when a description of directions is particularly required, the direction perpendicular to the paper surface is defined as the Z direction, and the X and Y directions perpendicular to the Z direction are defined as shown in FIG.

[0033] As shown in Figure 12, the light source device 10 is broadly divided into two light source units, a first light source unit Md1 and a second light source unit Md2, and is a device for extracting uniform illumination light by combining light emitted from the first light source unit Md1 and the second light source unit Md2, which are separate light sources, using a prism 2 and allowing the light to enter a light tunnel 3, which is a light homogenizing element.

[0034] The prism 2 is an optical element whose purpose is to guide the light F1 from the first light source unit Md1 in the same direction as the light F2 from the second light source unit Md2. In this embodiment, the prism 2 is a polyhedron having four or more faces, and one of the faces of the prism 2 onto which the light F1 from the first light source unit Md1 is incident forms a reflecting surface 2A. The prism 2 is a means for combining and guiding light from two or more light source units in approximately the same direction, and is not limited to such a configuration; it may also have a more multifaceted configuration in order to combine light from three or more light source units. The reflecting surface 2A may be configured, for example, by a triangular prism with the reflecting surface 2A formed on an inclined surface, or may be configured by a plane mirror formed on one side. This embodiment is used in at least two light source units. In the case of a lighting device having two light source units, for example, as shown in Fig. 12, the present invention is used in a first light source unit Md1 as one light source unit and a second light source unit Md2 as the other light source unit. As such, the present invention can be used with any two of at least two light source units, but the following embodiments will focus particularly on the first light source unit Md1 and the second light source unit Md2. Furthermore, the third, fourth, and other additional light source units other than the two light source units to which the present invention is applied do not necessarily have to be light sources that use phosphor wheels, and may be light source units that emit monochromatic or multiple wavelengths of light. Furthermore, the third, fourth, and other additional light source units other than the two light source units may be provided in a manner that they are attached to the outside of the housing of light source device 10. Furthermore, the prism 2 may be provided with, for example, a diffusing surface. By providing a diffusing surface in this way, it is possible to eliminate unevenness in the color and brightness of the light passing through the diffusing surface. Note that, as a method for eliminating such unevenness in color and brightness, providing a separate diffusing plate is also an option, and the configuration is not limited to providing a diffusing surface.

[0035] With this configuration, the prism 2 reflects the light F1 from the first light source unit Md1 and guides it to the light tunnel 3, which is a light homogenizing element, as a light beam traveling in approximately the same direction as the light F2 from the second light source unit Md2 passing near the prism 2 (for example, above the paper in the Z direction).

[0036] The light tunnel 3 functions as a light mixing element for homogenizing the incident light and outputting illumination light in which the illuminance and light intensity distribution of the light F1 and F2 from the two light source units Md1 and Md2 are homogenized. The light tunnel 3 has its exit position from the prism 2 adjusted so that, at its entrance position, the light F1 from the first light source unit Md1 and the light F2 from the second light source unit Md2 are both within the limit of the incident angle of the light tunnel 3.

[0037] The first light source unit Md1 and the second light source unit Md2 have the same configuration. Furthermore, the first light source unit Md1 and the second light source unit Md2 have the same configuration as the elements described in the first embodiment, and so the same numbers are used to denote these elements, and the description thereof will be omitted where appropriate.

[0038] As described in the first embodiment, the light beam reflected by the wavelength conversion element 17 passes through the first focusing optical system 16 again and is focused by the second focusing optical system 18, and if it is light F1 from the first light source unit Md1, it is turned back by the reflecting surface 2A and passes through the color wheel 20 to enter the light tunnel 3. Alternatively, light F2 from second light source unit Md2 passes above or below prism 2 on the plane of the drawing without passing through prism 2, passes directly through color wheel 20, and enters light tunnel 3. Of course, light F2 from second light source unit Md2 is not limited to passing without passing through prism 2, and may be transmitted through the prism in part or in whole. As in the first embodiment, the color wheel 20 is a disk that integrates filters for the red region R, blue region B, green region G, and yellow region Y. As it rotates, incident light F1 and F2 from light source units Md1 and Md2 passes through it, converting the incident light into time-divided light of red, blue, green, and yellow. In this way, the light of each color generated over time by the wavelength conversion element 17 and the color wheel 20 is guided to the DMD 101 through the illumination optical system 102 to form an image corresponding to each color, which is then enlarged and projected onto the projection surface 104 by the projection optical system 103.

[0039] In this embodiment, when the light F1 from the first light source unit Md1 and the light F2 from the second light source unit Md2 are irradiated onto the color wheel 20, a third illumination spot P3 is formed as shown in Fig. 13. In Fig. 13, the third illumination spot P3 due to the light F1 is indicated by a dashed line P31, and the third illumination spot P3 due to the light F2 is indicated by a solid line P32. Further, a virtually defined illumination range including these two third illumination spots is a third illumination spot P3, which is roughly a rectangle enclosed by the dashed line P31 and the solid line P32 or an ellipse having a focus at the center of gravity of the illumination spot P31 of the first light source unit Md1 and the illumination spot P32 of the second light source unit Md2. The third illumination spot P3 as shown in Fig. 13 is a "virtual ellipse formed to encompass two incident lights."

[0040] Light tunnel 3 is an optical element that uniformizes the illuminance of light incident at its entrance and outputs it to its exit. Therefore, in order to make the illuminance at the entrance of light tunnel 3 uniform over as wide an area as possible, it is preferable that the fourth illumination spots P4 of light F1 and F2 are positioned at the entrance of light tunnel 3 so that they do not overlap each other. In other words, it is also preferable that the third irradiation spots P3 on the color wheel 20 in the previous stage do not overlap each other. Furthermore, in conventional technology, when combining light F1 and F2 from two light source units Md1 and Md2, it was common for the first light source unit Md1 and the second light source unit Md2 to be arranged horizontally with respect to the X direction, which is the longitudinal direction of the light tunnel 3.

[0041] Therefore, in order to form the fourth illumination spot P4 so that they do not overlap each other, a commonly known configuration is to arrange the first light source unit Md1 and the second light source unit Md2 in a staggered manner, creating a gap in the Z direction, which is the height direction.

[0042] In this case, if the first light source unit Md1 and the second light source unit Md2 are shifted in the Z direction, the respective third illumination spots P3 on the color wheel 20 will also be shifted from each other in the Z direction, as shown in Figure 14, and therefore the third illumination spots P3 of the two lights will often have a shape in which the major axis is arranged along the radial direction of the color wheel 20. With this arrangement, the third illumination spots P31 and P32 of the two lights are arranged along the radial direction of the color wheel 20, thereby preventing an unnecessary increase in spoke time. That is, when the major axis direction of the ellipse encompassing the two incident lights is substantially parallel to the radial direction of the color wheel 20, as shown in FIG. 14, an unnecessary increase in spoke time can be prevented. Note that, in this embodiment, when the difference in angle between the major axis direction of the ellipse of the third illumination spot P3 in FIG. 14 and the radial direction of the color wheel 20 is within ±10 degrees, they can be considered to be substantially parallel to each other. In this case, naturally, the fourth illumination spot P4 will also have the same shape, and the opening that is the entrance to light tunnel 3 will also have a rectangular shape that surrounds the elliptical third illumination spot P3. In other words, if the short sides of the opening of light tunnel 3 can be arranged so that they are parallel to the circumferential direction of color wheel 20, as shown in Figure 14, unnecessary increases in spoke time can be prevented even when multiple light source units Md1, Md2 are used. Regarding the range of "parallel" here, as described above, if the angle between the short sides of the opening of light tunnel 3 and the circumferential direction of color wheel 20 is within ±10 degrees, it can be considered as "parallel to the circumferential direction."

[0043] However, since the size and inclination of the opening of the light tunnel 3 are generally determined by the size of the illumination optical system 102 and DMD 101 downstream of the light source device 10, it is often difficult to achieve such an arrangement aimed solely at reducing spoke time.

[0044] Furthermore, when attempting to miniaturize the entire light source device 10, since the color wheel 20 and the wavelength conversion element 17, which is a phosphor wheel, are circular, the closer the optical axis center of the optical system of the first light source unit Md1 and the second light source unit Md2 is to the rotation axis center of the color wheel 20 and the wavelength conversion element 17, the smaller the thickness of the entire device tends to be and the easier it is to miniaturize it in the Z direction. This attempt at miniaturization is shown in Fig. 15, which shows a schematic representation of the optical path, focusing on the optical axis between the first light source unit Md1 and the second light source unit Md2. Note that Fig. 15 shows only the optical axis in a schematic manner, and does not take into account the positional relationship with each optical element, etc. Since the color wheel 20 is a circular component with a considerable area, similar to the wavelength conversion element 17, as is clear from Figure 15, if the optical axes of the first light source unit Md1 and the second light source unit Md2 are arranged so that the difference in height in the Z direction from the rotation axis of the color wheel 20 is small, the light source device 10 can be further miniaturized in the Z direction.

[0045] If such an arrangement is aimed for and the aim is to make the illuminance at the opening of the light tunnel 3 uniform over a wide range as described above, it is better to arrange the third illumination spots P31 and P32 of the light from the first light source unit Md1 and the second light source unit Md2, respectively, so that they are approximately parallel to the circumferential direction of the color wheel 20, as shown in Figure 16. In other words, the rectangular opening of light tunnel 3, having long and short sides, is arranged such that the long sides of light tunnel 3 follow the arrangement direction of third illumination spots P31, P32, which are light source spot lights, and the direction of these long sides is perpendicular to the radial direction of color wheel 20. Also, in Fig. 16, a virtual ellipse is not depicted in consideration of visibility of the drawing, but a virtual ellipse encompassing the two incident light beams may be considered using the same concept as in Figs. 13 and 14.

[0046] In this way, if the third irradiation spots P31 and P32 of the light from the first light source unit Md1 and the second light source unit Md2 are arranged side by side in the circumferential direction of the color wheel 20, as already mentioned, the problem of increased spoke time is likely to occur.

[0047] Therefore, in this embodiment, as in the first embodiment, the first filter group 21 and the second filter group 22 of the color wheel 20 are arranged so that, among the multiple color filters arranged in each, there is at least one location where color filters having the same or similar light transmission characteristics are adjacent to each other. With this configuration, even if the first light source unit Md1 and the second light source unit Md2 are arranged in a way that makes it easy for the spoke time of the color wheel 20 to increase due to various constraints, it is possible to suppress the increase in spoke time by arranging each color filter of the color wheel 20. In this way, the present invention is particularly effective even when the major axis direction of the virtual ellipse formed to encompass the two incident light beams is approximately parallel to the circumferential direction of the color wheel 20, and can suppress an increase in the spoke time of the color wheel 20.

[0048] Also in this embodiment, the areas or central angles of the multiple color filters arranged in each of the first filter group 21 and the second filter group 22 are set to be unequal for each color, and the area ratio or central angle ratio of each color of the multiple color filters that make up the first filter group 21 is set to be approximately equal to the area ratio or central angle ratio of each color of the multiple color filters that make up the second filter group 22. With this configuration, it is possible to increase the number of segments of the color filter while reducing the spoke time and improving color purity.

[0049] Now, the relationship between the color wheel, incident light, and spoke time will be described in detail. FIG. 17 shows the time change in the projection of incident light, which is a light source spot light, onto color wheel 300 in the conventional color wheel 300 shown in FIG. The projection of light projected onto color wheel 300 is shown as fifth illumination spot P5. FIGS. 17(a) and 17(b) show the positional relationship of incident light in each color filter from the start to the end of color processing. The time during which incident light is available in color wheel 300 starts from the state shown in FIG. 17(a) in which the entire fifth illumination spot P5, which is the projection of incident light shown as an ellipse, is completely within a specific color filter of color wheel 300, and ends at the moment when the blue region B, which is one color section, is completed and part of fifth illumination spot P5 crosses the boundary line with other colors, as shown in FIG. 17(b). This period is referred to as the valid period.

[0050] As already mentioned, the light source device 10 performs color processing for each filter within the effective period, and since during the effective period color processing of the pure filter can be performed without mixing with other colors, the longer the effective period, the brighter the colors that can be expressed and the better the gradation. The effective period is the angle of the filter minus the time required for the incident light to pass through the angle in the circumferential direction (spoke time). In Figure 17, if the angular velocity ω of the rotation of the color wheel 300 is a constant, the spoke time is the time it takes for the spoke to scan the fifth illumination spot P5 indicated by θα, and is therefore θα / ω. That is, the effective period T, which is the color processing time in the color wheel 300, is determined by the angle θ of any color filter of the color wheel 300. X , and can be expressed as follows using spoke time Ts:

[0051]

number

[0052] That is, effective period (color processing time) = filter angle (time) - spoke time (time). As is clear from Equation 1, the effective period is uniquely determined by each filter angle.

[0053] 2, the effective period is set long enough to allow sufficient color processing to be performed on the spatial light modulator, and is performed within the projection device 816. The effective period required for processing is determined by the filter angles in the color wheel 300 of the projection device 816. Therefore, when designing the color wheel, the spoke time and filter angle must be taken into consideration in order to calculate the required effective period. In many cases, the angles of the color filters are not set at equal intervals, and the filter in the blue region B, which has the least effect on brightness among the three primary colors of light, is set at the narrowest angle. In this way, narrowing the filter in the blue region B, which has the least effect on brightness among the filters, naturally expands the angle over which Y, G, and R can be distributed, thereby increasing the degree of freedom in setting the brightness and color temperature between each color.

[0054] FIG. 18 shows an example of an embodiment of the present invention in which the total angle of each color is kept the same as that of the color wheel 300 shown in FIG. 17, but the number of filters is doubled to achieve double-speed driving. That is, while the four color filters shown in FIG. 17 have a red region R, a blue region B, a green region G, and a yellow region Y, FIG. 18 is configured with eight color filters including a first filter group 21 having a red region R, a blue region B, a green region G, and a yellow region Y, and a second filter group 22 similarly having a red region R, a blue region B, a green region G, and a yellow region Y. In this way, by doubling the number of plates while keeping the total angle of each color per rotation of the color wheel the same, the color changes twice per rotation, making it possible to easily double the speed without increasing the rotation speed.

[0055] In this color wheel 20, the sum of the angles of the first filter group 21 and the second filter group 22 is set to match that of the color wheel 300. In other words, the total angle of each color filter per revolution of the color wheel is the same. However, if the number of color filters were simply increased to eight as shown in FIG. 18, the spoke time would double accordingly. Furthermore, because the above-mentioned effective period is calculated for each color filter, there is the problem that the effective period for each color process is inevitably reduced. Thus, while simply using eight color filters can easily double the speed, it also results in a color wheel with poor color reproducibility due to an increase in spoke time, which is inconvenient for color processing, and a corresponding decrease in the effective period.

[0056] Therefore, in order to solve this problem, Figure 19 shows a configuration of a color wheel 20 having a first filter group 21 arranged so that the filters switch in the order of blue region B, green region G, yellow region Y, and red region R along the rotation direction 20r, and a second filter group 22 arranged so that the filters switch in the reverse order of the first filter group 21 along the rotation direction 20r, i.e., red region R, yellow region Y, green region G, and blue region B. With this configuration, there is no boundary between R / R at the positions of the red region R and the blue region B where the first filter group 21 and the second filter group 22 are adjacent, so they can be treated as one color and there is no spoke time. Therefore, the effective period required for color processing can be sufficiently secured, and a bright color wheel with excellent color gradation can be realized.

[0057] A specific operation of such a configuration is shown in FIG. The dashed line a shown in FIG. 20 is an imaginary boundary between the filters of the first filter group 21 and the second filter group 22, which are adjacent to each other. The color wheel 20 rotates clockwise as shown in the rotation direction 20r in Figure 20, and performs color processing of the filter shown as blue area B within the period from the point shown in Figure 20(a), which is the start timing of the effective period, to the point shown in Figure 20(c), which is the end timing of the effective period. 20(a) to 20(c), the timing at which the dashed line a, which is the boundary between the first filter group 21 and the second filter group 22, is passed is shown as FIG. 20(b). Although the processes performed by the first filter group 21 and the second filter group 22 are different, at the timing shown in Fig. 20(b), the blue region B and the red region R between the first filter group 21 and the second filter group 22 are adjacent to each other and have the same or similar colors. Therefore, it is possible to perform color processing on the adjacent filters as a single filter. With this configuration, spoke time does not occur at the timing shown in Figure 20(b), and the effective period required for color processing can be sufficiently secured, making it possible to realize a bright color wheel with excellent color gradation.

[0058] The size of the spot incident on the color filter and the central angle of the filter will also be discussed. As shown in FIG. 21, in this embodiment, a case will be considered in which the projection of incident light that is incident on the color filters is schematically represented by a sixth illumination spot P6. The length of the sixth irradiation spot P6 along the circumferential direction of the color wheel 20, or the length of the spot in the direction in which the boundary line of the color filter scans, is defined as α. The central angle θ corresponding to the circumferential length α of the sixth irradiation spot P6 is defined as α The central angle θ α In other words, when lines are drawn radially from the rotation center O of the color wheel 20 to the sixth irradiation spot P6, this is the maximum angle formed by the lines passing through the sixth irradiation spot P6. This central angle θ α is the central angle θ of each color filter R , θ B , θ G , θ YWhen compared with the central angle θ of an arbitrary color filter, a smaller angle is advantageous because it allows for a longer effective period. X For θ X <θ α If this happens, it will be inappropriate because it will be impossible to obtain a valid period, as is clear from Equation 1.

[0059] In the red region R where the first filter group 21 and the second filter group 22 are adjacent to each other, the central angle θ of the red filters is R In reality, the two red filters of the first filter group 21 and the second filter group 22 are combined. α <θ R The condition above is insufficient because it includes a configuration in which the color filter crosses the broken line a at the same time as it leaves the boundary line of the color filter. As shown in FIGS. 21 and 22, in the case of adjacent color filters, 2θ α <θ R , 2θ α <θ B If this is not true, the validity period will not be obtained. In this way, in the red region R and the blue region B where the first filter group 21 and the second filter group 22 are adjacent to each other, the central angle θ X θ α <2θ X Set it so that: That is, in this embodiment, the sum of the central angles θ of two adjacent color filters is R , θ B is the central angle θ corresponding to the spot diameter of the light incident on the plurality of color filters. α is more than twice the This configuration makes it possible to provide a color wheel that has a longer effective period and is capable of bright color processing with a rich color gradation.

[0060] 22, the size (spot diameter) of the sixth irradiation spot P6 in a direction perpendicular to the boundary scanning direction is indicated as β. β is the spot diameter in a direction perpendicular to the scanning direction, and is the length of the sixth irradiation spot P6 along the radial direction of the color wheel 20. In this embodiment, when the circumferential length of the sixth irradiation spot P6 is set to α and the radial length thereof is set to β, the relationship is set to β>α. In this way, when the lengths of α and β are different, i.e., there is anisotropy, it is desirable to adjust the irradiation direction of the sixth irradiation spot P6 so that the length β in the direction perpendicular to the scanning direction of the boundary of the color filter is longer than the length α in the scanning direction of the boundary of the color filter. By using the arrangement shown in Figure 22, the time it takes for the boundary of the color filters to pass can be shortened, so the spoke time can be shortened compared to an arrangement where α > β, and a longer effective period can be ensured. With this configuration, it is possible to ensure a sufficient effective period for color processing, thereby realizing a bright color wheel with excellent color gradation.

[0061] As described above, in order to shorten the spoke time and extend the effective period, β>α is set, but the relationship between α and β is determined according to the arrangement of the light source units. Therefore, depending on the arrangement of the light source units, there may be restrictions on the arrangement of the color wheel 20 in order to satisfy the relationship β>α. As shown in FIG. 12, in addition to the color wheel 20, the light source device 10 also contains the light source 11, the wavelength conversion element 17, the circuits and electronic boards that drive them, the cooling fan, and so on. Therefore, depending on the positioning of the color wheel 20 that satisfies β>α, the color wheel 20 may protrude beyond the other components, resulting in an increase in the size of the entire device. Therefore, in order to reduce the overall size of the light source device 10 in relation to other components that make up the light source device 10 (such as the light source 11 and wavelength conversion element 17), the ratio α may be set to be greater than β. Even if the configuration satisfies α>β, as shown in FIG. 22, the total central angle θ of two adjacent color filters is X is the central angle θ corresponding to the spot diameter of the light incident on the multiple color filters. α If the value is set to be at least twice as large as the above, the spoke time can be reduced. In this way, the present invention can shorten the spoke time and extend the effective period regardless of the relationship between α and β of the spot.

[0062] Furthermore, the embodiment has been described using a composite spot formed by two spots from the first light source unit Md1 and the second light source unit Md2, but it is of course also possible to apply this to a spot obtained by a single light source unit. Furthermore, whether it is a single spot or a composite spot formed by two or more light source units, the shape of the spot does not matter: whether it is elliptical, circular, rectangular, or any other shape, the color wheel configuration of the present invention is effective in reducing spoke time.

[0063] In addition, such α and β are, for example, a general example of a method for measuring the size of a beam spot, where the light intensity is 1 / e 2 The width of the base can be treated as the spot diameter. Furthermore, when multiple incident light spots are arranged in a line along the circumferential direction in the configurations shown in Figures 15 and 16, valleys may occur in the light intensity distribution as shown in Figure 23. Furthermore, these valleys may occur when the light intensity temporarily drops to 1 / e 2 It may be less than that. Therefore, when there are multiple incident light spots, the light intensity between the multiple incident light spots is 1 / e 2 Even if there is a position where the normalized light intensity is less than 1 / e 2 Among the multiple positions where the distance is less than 1 / 2, the distance between the two most distant points may be used as the "spot diameter" as shown in FIG. By defining the spot diameter in this way, the spot diameter can be determined from the overall size of the multiple incident light beams, regardless of the position of each individual incident light beam, even when multiple light source spot lights are incident on color wheel 20. With this configuration, even when the incident light beams are somewhat separated from one another, it is possible to adjust the incident position appropriately while maintaining the effect of reducing spoke time, thereby providing a color wheel capable of bright color processing with a rich color gradation.

[0064] The aspects of the present invention are as follows, for example. [1] The color wheel 20 of the present invention includes a first filter group 21 in which a plurality of color filters having different light transmission characteristics are arranged, and a second filter group 22 in which a plurality of color filters having different light transmission characteristics are arranged, and is a color wheel in which the first filter group 21 and the second filter group 22 are arranged so that the plurality of color filters of the first filter group 21 and the plurality of color filters of the second filter group 22 are aligned in the circumferential direction. In addition, the first filter group 21 and the second filter group 22 are arranged so that, among the multiple color filters arranged in each, there is at least one location where color filters having the same or similar light transmission characteristics are adjacent to each other. The area or central angle of each of the different colors of the multiple color filters arranged in each of the first filter group 21 and the second filter group 22 is set to be uneven, and the area ratio or central angle ratio of each color of the multiple color filters constituting the first filter group 21 is approximately equal to the area ratio or central angle ratio of each color of the multiple color filters constituting the second filter group 22. Here, the angle ratio being approximately equal specifically means that the difference between the central angle of a color filter in the first filter group 21 and the central angle of a color filter in the second filter group 22 is within ±5 degrees. With this configuration, it is possible to increase the number of segments of the color filter while reducing the spoke time and improving color purity.

[0065] [2] In addition to the configuration described in [1], the color wheel 20 of the present invention is characterized in that the combined central angle of two adjacent color filters is at least twice the spot diameter of the light incident on the plurality of color filters. With this configuration, it is possible to provide a color wheel that can achieve a longer effective period and can perform bright color processing with a rich color gradation.

[0066] [3] In addition to the configurations described in [1] and [2], the spot diameter of the color wheel 20 of the present invention is characterized in that it is determined by the length α of the projection of the incident light in the direction in which the boundary of the color filter scans. This configuration reduces the spoke time of light incident on the color wheel 20, making it possible to extend the effective period, and provides a color wheel capable of bright color processing with a rich color gradation.

[0067] [4] In addition to the configuration described in any one of [1] to [3], the color wheel 20 is characterized in that, when the length of the projection of light incident on the color filter in the direction in which the boundary of the color filter scans is α and the length in the direction perpendicular to the scanning direction of the boundary of the color filter is β, β>α. This configuration further reduces the spoke time of light incident on the color wheel 20, making it possible to extend the effective period, and provides a color wheel capable of bright color processing with a rich color gradation.

[0068] [5] In addition to the configuration described in any one of [1] to [3], the color wheel 20 is characterized in that, when the length of the projection of light incident on the color filter in the direction in which the boundary of the color filter scans is α and the length in the direction perpendicular to the scanning direction of the boundary of the color filter is β, α>β. This configuration contributes to the miniaturization of the entire light source device 10 without changing the spot shape of the light incident on the color wheel 20 in the light source device 10, and also reduces the spoke time, making it possible to extend the effective period, thereby providing a color wheel that is bright and capable of color processing with a rich color gradation.

[0069] [6] In addition to the configuration described in any one of [1] to [5], the color wheel 20 is characterized in that two or more lights are incident on the color filters. According to this configuration, even when a plurality of incident light beams are used by utilizing a plurality of light source units such as the first light source unit Md1 and the second light source unit Md2, the spoke time can be reduced and color purity can be increased.

[0070] [7] In addition to the configuration described in any one of [1] to [3] or [5], the color wheel 20 is characterized in that the long axis direction of the virtual ellipse formed to encompass two or more incident light beams is approximately parallel to the circumferential direction of the color wheel 20. According to this configuration, even if the arrangement is such that the two third irradiation spots P31, P32 of the incident light are arranged side by side along the circumferential direction, which is likely to increase the spoke time, it is possible to prevent an increase in the spoke time and increase the color purity.

[0071] [8] In addition to the configuration described in any one of [1] to [7], the color wheel 20 is characterized in that the two or more incident lights are each generated from a different light source. According to this configuration, even if there are two third irradiation spots P31 and P32 of incident light, it is possible to prevent an increase in spoke time and to improve color purity.

[0072] [9] In addition to the configuration described in any one of [1] to [8], the color wheel 20 is characterized in that, among the multiple color filters arranged in each of the first filter group 21 and the second filter group 22, adjacent color filters with the same light transmittance are made from a single component. With this configuration, for example, there is no transition portion between the blue region B of the first filter group 21 and the blue region B of the second filter group 22 that are adjacent to each other, so the spoke time can be further reduced, and since the blue region B of the first filter group 21 and the blue region B of the second filter group 22 that are adjacent to each other can be produced from the same material, costs can be reduced by reducing the number of labor hours and parts.

[0073]

[10] In addition to the configuration described in any one of [1] to [9], a rectangular light tunnel 3 having long and short sides is provided after passing through the color wheel 20, and the long side of the opening of the light tunnel 3 is arranged along the arrangement direction of the irradiation spots P3. According to this configuration, even when a plurality of light source units Md1 and Md2 are used, it is possible to prevent an unnecessary increase in spoke time.

[0074]

[11] The present invention is characterized by a light source device 10 having a color wheel 20 having the configuration described in any one of [1] to

[10] . With this configuration, it is possible to maintain the illuminance of the illumination light emitted from the light source device 10 uniform, and obtain light with a short spoke time and high color purity.

[0075]

[12] The present invention is characterized by an image projection device 100 having a light source unit equipped with a color wheel 20 described in any of the configurations [1] to

[10] , and a projection optical system 103 that irradiates the light source light emitted from the light source unit onto a DMD 101 and enlarges and projects the modulated image. With this configuration, it is possible to maintain the illuminance of the illumination light emitted from the light tunnel 3 uniform, and to obtain light with a short spoke time and high color purity.

[0076] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and unless otherwise specifically limited in the above description, various modifications and changes are possible within the scope of the spirit of the present invention as described in the claims. The effects described in the embodiments of the present invention are merely examples of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention. [Explanation of symbols]

[0077] 3...Light mixing element (light tunnel) 10…Light source device 20...Color Wheel 21...First filter group 22...Second filter group 100...Projection device 101... Two-dimensional optical modulator (DMD) 103...Projection optical system θG, θY…center angle θα: central angle corresponding to the spot diameter α: Spot diameter in the direction in which the boundary of the color filter scans β: Spot diameter in the direction perpendicular to the scanning direction of the color filter boundary Md1, Md2...light source modules [Prior art documents] [Patent documents]

[0078] [Patent Document 1] Japanese Patent Publication No. 2023-099536 [Patent Document 2] Patent No. 6205835 [Patent Document 3] Patent No. 4281385 [Patent Document 4] US Patent US10634901

Claims

1. a first filter group in which a plurality of color filters having different light transmission characteristics are arranged; a second filter group in which a plurality of color filters having different light transmission characteristics are arranged; Including, a color wheel in which the first filter group and the second filter group are arranged so that the plurality of color filters of the first filter group and the plurality of color filters of the second filter group are aligned in a circumferential direction, the first filter group and the second filter group are arranged so that, among the plurality of color filters arranged in each of the first filter group and the second filter group, color filters having the same or similar light transmission characteristics are adjacent to each other in at least one location; The areas or central angles of the different colors of the plurality of color filters arranged in each of the first filter group and the second filter group are set to be unequal, and A color wheel characterized in that the area ratio of each color of the plurality of color filters constituting the first filter group or the angular ratio of the central angles thereof is approximately equal to the area ratio of each color of the plurality of color filters constituting the second filter group or the angular ratio of the central angles thereof.

2. 10. The color wheel of claim 1, A color wheel characterized in that the combined central angle of two adjacent color filters is at least twice the central angle corresponding to the spot diameter of light incident on the plurality of color filters.

3. 3. A color wheel according to claim 2, A color wheel according to claim 1, wherein the spot diameter is defined by a length of the projection of the light in a scanning direction of the boundary of the color filter.

4. 10. The color wheel of claim 1, A color wheel characterized in that, when the length of the projection of light incident on the color filter in the direction in which the boundary of the color filter scans is α and the length of the projection of the light incident on the color filter in the direction perpendicular to the scanning direction of the boundary of the color filter is β, β>α.

5. 10. The color wheel of claim 1, A color wheel characterized in that, when the length of the projection of light incident on the color filter in the scanning direction of the boundary of the color filter is α and the length of the projection of the light incident on the color filter in the scanning direction of the boundary of the color filter is β, α>β.

6. 10. The color wheel of claim 1, A color wheel characterized in that two or more light beams are incident on the color filters.

7. The color wheel of claim 5 A color wheel, characterized in that the major axis direction of the virtual ellipse formed to encompass the two or more incident light beams is approximately parallel to the circumferential direction of the color wheel.

8. 7. A color wheel according to claim 6, A color wheel, wherein the two or more incident lights are generated from different light sources.

9. 10. The color wheel of claim 1, A color wheel characterized in that, among the plurality of color filters arranged in each of the first filter group and the second filter group, adjacent color filters having the same light transmittance are made from a single component.

10. 8. A color wheel according to claim 7, A color wheel characterized in that a rectangular light mixing element (light tunnel) having long and short sides is provided after the light passes through the color wheel, and the long sides of the light mixing element are arranged along the arrangement direction of the light source spot light.

11. A light source device comprising the color wheel according to any one of claims 1 to 10.

12. a light source module comprising the color wheel according to any one of claims 1 to 10; a projection optical system that irradiates the light source light emitted from the light source module onto a two-dimensional light modulator and enlarges and projects a modulated image.

Images