Light source device and projection device

Abstract

To improve color purity.SOLUTION: A light source device comprises: a first light source that emits first excitation light; a second light source that is provided separate from the first light source and emits second excitation light; a first wavelength conversion element that is excited by the first excitation light and emits first fluorescence; a second wavelength conversion element that is excited by the second excitation light and emits second fluorescence; a first optical element that is arranged on a path of the first fluorescence; and a second optical element that is arranged on a path of the second fluorescence. At least any one of the first optical element and the second optical element has a conversion unit that transmits or reflects the first fluorescence or the second fluorescence to convert the fluorescence into color light having an optical spectrum obtained by cutting a part of a wavelength band of an optical spectrum of at least any one of the first fluorescence and the second fluorescence.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] A light source device for a projector requires a light source that outputs light of red, green, yellow, blue, etc. to generate white light. The light source device uses a solid-state light source such as an LED (Light Emitting Diode) or a laser. However, solid-state light sources, particularly those for green, yellow, and red, have poor luminous efficiency and temperature characteristics, making it difficult to create a bright projector. Therefore, a conventional technology that generates colors such as yellow, green, and red by exciting a phosphor with blue laser light, which has good luminous efficiency, has already been widely used.

[0003] Patent Document 1 discloses a technology for achieving a bright projector with good color reproducibility, in which phosphors are provided on one side and the other side of a phosphor wheel, each side is excited by a light source that irradiates excitation light, and a light-guiding optical system is provided that guides the fluorescence emitted from each phosphor along the same optical path.

[0004] Patent Document 2 discloses a technology in which a phosphor wheel and a color wheel are divided into segments and driven in synchronization with each other, with the aim of providing a projector that is bright and has good color purity. Summary of the Invention [Problem to be solved by the invention]

[0005] However, according to the conventional technology, since phosphors have a wide light spectrum, if they are used as they are for illuminating a projector, there is a problem that the color purity of the projector deteriorates.

[0006] Furthermore, according to conventional technology, a color wheel with multiple dichroic filters arranged in the circumferential direction of a rotating body is used to improve color purity. In this case, it is assumed that blue, red, green, and other light beams are emitted in a time-division manner, which limits the light emission time of each color, making it difficult to create a bright projector. Furthermore, according to conventional technology, when light is irradiated between segments of the color wheel, the two colors of light mix, resulting in the problem of periods of poor color purity.

[0007] The present invention has been made in view of the above, and has an object to further increase color purity. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the present invention provides a fluorescence imaging device including a first light source that emits first excitation light, a second light source that is provided separately from the first light source and that emits second excitation light, a first wavelength conversion element that is excited by the first excitation light and emits first fluorescence, a second wavelength conversion element that is excited by the second excitation light and emits second fluorescence, a first optical element that is arranged on a path of the first fluorescence, and a second optical element that is arranged on a path of the second fluorescence. an adjusting lens provided between the first optical element and the second optical element, which adjusts the state of the first fluorescent light or the first color light emitted from the first optical element to a substantially parallel light; and at least one of the first optical element and the second optical element has a conversion section that transmits or reflects the first fluorescence or the second fluorescence, thereby converting the fluorescence into color light having an optical spectrum in which a part of a wavelength band of the optical spectrum of at least one of the first fluorescence or the second fluorescence is cut off. [Effects of the Invention]

[0009] The present invention has the effect of making it possible to further increase color purity. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram schematically illustrating a configuration of a light source device according to a first embodiment. [Figure 2]FIG. 2 is a diagram showing an example of the optical spectrum of each light. [Figure 3] FIG. 3 is a side view showing the configuration of the mirror. [Figure 4] FIG. 4 is a diagram showing an example of the transmittance spectrum of the dichroic filter layer of the mirror. [Figure 5-1] FIG. 5-1 shows the overall configuration of the light source device and illustrates the green light path. [Figure 5-2] FIG. 5-2 shows the overall configuration of the light source device and illustrates the red light path. [Figure 5-3] FIG. 5-3 shows the overall configuration of the light source device and illustrates the blue light path. [Figure 6] FIG. 6 is a diagram schematically showing a modified example of the configuration of the light source device. [Figure 7] FIG. 7 is a diagram schematically showing the configuration of a light source device according to the second embodiment. [Figure 8] FIG. 8 is a diagram showing an example of the optical spectrum of each light. [Figure 9] FIG. 9 is a diagram showing an example of the transmittance spectrum of the dichroic filter layer of the mirror. [Figure 10] FIG. 10 is a diagram schematically illustrating the configuration of a light source device according to the third embodiment. [Figure 11] FIG. 11 is a diagram schematically showing the configuration of a light source device according to the fourth embodiment. [Figure 12] FIG. 12 is a diagram showing an example of the optical spectrum of each light. [Figure 13] FIG. 13 is a diagram showing an example of the transmittance spectrum of the dichroic filter layer of the mirror. [Figure 14] FIG. 14 is a diagram schematically showing the configuration of a light source device according to the fifth embodiment. [Figure 15] FIG. 15 is a diagram showing an example of the optical spectrum of each light. [Figure 16] FIG. 16 is a diagram showing an example of the transmittance spectrum of the dichroic filter layer of the mirror. [Figure 17]FIG. 17 is a diagram showing the overall configuration of the light source device. [Figure 18] FIG. 18 is a schematic configuration diagram showing a projector according to the sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of a light source device and a projection device will be described in detail with reference to the accompanying drawings.

[0012] (First embodiment) FIG. 1 is a diagram illustrating a schematic configuration of a light source device 1 according to a first embodiment, and FIG. 2 is a diagram illustrating an example of the optical spectrum of each light. As shown in FIG. 1, the light source device 1 includes three laser light sources 11, 12, and 13 that emit laser light, two phosphor wheels 21 and 22 that are provided with phosphors 41 and 42 that emit fluorescence when irradiated with laser light, and two mirrors 31 and 32 that are arranged to transmit the laser light and reflect the fluorescence. As shown in FIG. 1, the light source device 1 irradiates light onto a light uniformizing element 90. When light enters the light uniformizing element 90, it mixes the incident light and outputs the mixed light as uniform light. The light uniformizing element 90 may be configured, for example, with a light tunnel, a rod integrator, or a fly's eye lens.

[0013] Laser light sources 11, 12, and 13 are blue laser light sources with a peak wavelength of, for example, 455 nm. Blue laser light (first excitation light) emitted from laser light source 11, which is a first light source, is used to excite phosphor 41 in phosphor wheel 21 via mirror 31. Blue laser light (second excitation light) emitted from laser light source 12, which is a second light source, is used to excite phosphor 42 in phosphor wheel 22 via mirror 32. Blue laser light emitted from laser light source 13, which is a third light source, is used as blue light (third colored light) as it is via mirrors 31 and 32.

[0014] In this embodiment, the same light source is used for all the laser light sources, but this is not limited thereto, and laser light sources 11 and 12 may be any light source that excites the phosphors 41 and 42 of the phosphor wheels 21 and 22. Laser light source 13 may be any light source with an arbitrary peak wavelength. The light source is not limited to a laser light source, and may be any light source that performs the above-mentioned functions.

[0015] Phosphor wheels 21 and 22 are disk-shaped and rotated by a motor. Phosphor wheel 21, which is a first wavelength conversion element, includes phosphor 41 that, when irradiated with laser light, converts the light into light with a longer wavelength than the laser light and emits fluorescence. Phosphor wheel 22, which is a second wavelength conversion element, includes phosphor 42 that, when irradiated with laser light, converts the light into light with a longer wavelength than the laser light and emits fluorescence. When blue laser light emitted from laser light source 11 is irradiated via mirror 31, fluorescent light 71 is emitted from phosphor 41 of phosphor wheel 21. When blue laser light emitted from laser light source 12 is irradiated via mirror 32, fluorescent light 72 is emitted from phosphor 42 of phosphor wheel 22.

[0016] For example, a green phosphor having a peak wavelength of about 515 nm is used as phosphor 41 of phosphor wheel 21. For example, a yellow phosphor having a peak wavelength of about 540 nm is used as phosphor 42 of phosphor wheel 22.

[0017] The phosphors 41 and 42 can be selected arbitrarily to suit the characteristics of the light desired to be used as projector illumination light. For example, a red phosphor with a peak wavelength of approximately 610 nm may be used as phosphor 41 of phosphor wheel 21. The same phosphor may also be used for phosphor 41 of phosphor wheel 21 and phosphor 42 of phosphor wheel 22.

[0018] Furthermore, in this embodiment, disk-shaped phosphor wheels 21, 22 that are driven to rotate by a motor are used, but the present invention is not limited to this and may be a fixed phosphor directly attached to a heat sink, etc. However, since the temperature of each phosphor 41, 42 rises when fluorescent light is emitted, rotating phosphor wheels 21, 22 can provide a cooling effect.

[0019] Fig. 3 is a side view showing the configuration of mirrors 31 and 32. As shown in Fig. 3, mirrors 31 and 32 are mainly made of, for example, a glass plate 35 that transmits visible light. Mirrors 31 and 32 are provided with a dichroic filter layer 36 on the surface of glass plate 35 that has the property of transmitting or reflecting light of a desired wavelength. Mirror 31 is a first optical element, and mirror 32 is a second optical element.

[0020] The dichroic filter layer 36, which is the conversion section, can arbitrarily determine the optical spectrum of the transmittance of the dichroic filter layer 36 (hereinafter referred to as the transmittance spectrum) in accordance with the characteristics of the light desired to be used as illumination light for the projector. The optical spectrum is an emission characteristic value that represents the intensity of light emitted from a light source for each wavelength.

[0021] 4 is a diagram showing an example of the transmittance spectrum of the dichroic filter layer 36 of the mirrors 31 and 32. In the transmittance spectrum shown in FIG. 4, light in a wavelength range where the vertical axis indicates 1 is transmitted, and light in a wavelength range where the vertical axis indicates 0 is reflected. It goes without saying that the transmittance does not have to be 100% or 0%.

[0022] 4, in this embodiment, the transmittance spectrum of the dichroic filter layer 36 of the mirror 31 is designed to reflect only green wavelengths of approximately 475 to 600 nm and transmit all other wavelengths. Also, in this embodiment, the transmittance spectrum of the dichroic filter layer 36 of the mirror 32 is designed to reflect only red wavelengths of approximately 600 nm or more and transmit all other wavelengths.

[0023] 2 and 4, the dichroic filter layer 36 of the mirror 31 converts the optical spectrum of the fluorescence 71 into colored light 81 having an optical spectrum that cuts off wavelengths other than those between 475 and 600 nm. Also, as shown in FIGS. 2 and 4, the dichroic filter layer 36 of the mirror 32 converts the optical spectrum of the fluorescence 72 into colored light 82 having an optical spectrum that cuts off wavelengths of 600 nm or less.

[0024] The mirrors 31 and 32 do not necessarily have to have the configuration shown in FIG. 2, and any configuration is possible as long as an arbitrary transmittance spectrum can be obtained.

[0025] Next, each optical path in the light source device 1 will be described.

[0026] As shown in FIG. 1 , laser light 61 emitted from laser light source 11 passes through mirror 31 and is irradiated onto phosphor 41 of phosphor wheel 21. Phosphor 41 of phosphor wheel 21 is excited by laser light 61 and emits fluorescent light 71. Due to the characteristics of dichroic filter layer 36 provided on mirror 31, only specific wavelengths, primarily green light, of fluorescent light 71 emitted from phosphor 41 of phosphor wheel 21 are reflected, resulting in colored light 81 having a different optical spectrum from that of fluorescent light 71 and traveling toward mirror 32. All of colored light 81 is transmitted through mirror 32 and travels toward light homogenizing element 90.

[0027] Laser light 62 emitted from laser light source 12 passes through mirror 32 and is irradiated onto phosphor 42 of phosphor wheel 22. Phosphor 42 of phosphor wheel 22 is excited by laser light 62 and emits fluorescent light 72. Due to the characteristics of dichroic filter layer 36 provided on mirror 32, only specific wavelengths, primarily red light, of the fluorescent light 42 emitted from phosphor 42 of phosphor wheel 22 are reflected, resulting in colored light 82 having a different optical spectrum from that of fluorescent light 72, which then travels toward light homogenizing element 90.

[0028] The laser light 63 emitted from the laser light source 13 passes through the mirror 31 and the mirror 32 and travels toward the light uniformizing element 90 .

[0029] As described above, the light source device 1 can generate white color by combining the colored light 81 (green component), the colored light 82 (red component), and the laser light 63 (blue component).

[0030] Regarding the relationship between light spectrum and color, a broad light spectrum results in low color purity due to the mixture of various colors, while a narrow light spectrum results in high color purity. Using light with high color purity broadens the range of colors that can be expressed. As shown in Figure 2, fluorescent light 71 and fluorescent light 72 have a very broad light spectrum and poor color purity. Therefore, it is better to use a dichroic filter or similar to enhance the color purity before using them as illumination. While conventionally, this was achieved using a color wheel equipped with a dichroic filter, this method uses a fixed dichroic filter layer 36. This solves the problem of a color wheel equipped with a dichroic filter limiting the emission time of each color (e.g., blue, red, green) and preventing a bright projector.

[0031] Here, another example of improving color purity will be given.

[0032] Fluorescence is generated by wavelength conversion of blue laser light using a phosphor, but not all of the blue laser light is converted into fluorescence, and some of it is emitted in the same direction as the fluorescence. When blue laser light mixes with fluorescence in this way, the color purity of the fluorescence deteriorates.

[0033] Even in such a case, with the configuration of this embodiment, the laser light 61 mixed with the fluorescent light 71 passes through the mirror 31 and can be separated from the colored light 81. Similarly, the laser light 62 mixed with the fluorescent light 72 passes through the mirror 32 and can be separated from the colored light 82.

[0034] Furthermore, each mirror 31, 32 has two functions: to guide the fluorescence 71, 72 emitted from the phosphors 41, 42 to the light homogenizing element 90, and to increase the color purity, so that the number of elements is small, making it possible to create a small, low-cost light source device.

[0035] Another problem with using a color wheel is the need for a motor to rotate the color wheel, which can lead to problems with lifespan and noise. Of all the elements used in a projector, the motor has the shortest lifespan and is therefore the bottleneck in the projector's lifespan. Currently, a phosphor wheel is often used in addition to the color wheel, and as more heat is added, the phosphor wheel is the bottleneck in the lifespan. However, many fixed phosphors that do not use motors have been developed, and it is expected that fixed phosphors will become the mainstream in the future. When this happens, the advantages of the method of the present invention, which does not use a color wheel, will become even more apparent.

[0036] Another problem with color wheels is the angle of incidence onto the dichroic filter. Color wheels are typically placed at a narrowed light spot (where the light spot is small) to minimize the time that two colors of light mix. Because focusing light requires a lens, as in Reference 2, light is incident on the color wheel at various angles. Dichroic filters are typically designed for a specific angle of incidence, and if light is incident at a different angle, the spectral characteristics of the transmitted light change. Incident light at such various angles can cause problems, such as the light used as illumination not having the desired spectral characteristics or reduced brightness. The method of the present invention does not require focusing light before passing through the dichroic filter, allowing all light to be incident at the angle specified by the dichroic filter's design, eliminating the above-mentioned problems.

[0037] Next, the lenses in the light source device 1 and the diffusion and collection states of light will be described in detail.

[0038] 5-1 to 5-3 are diagrams showing the overall configuration of the light source device 1. Fig. 5-1 shows the green light path in the light source device 1, Fig. 5-2 shows the red light path in the light source device 1, and Fig. 5-3 shows the blue light path in the light source device 1.

[0039] First, the green light path will be described. As shown in Fig. 5-1, laser light 61 emitted from laser light source 11 is collected by lens 51, approximately collimated by lens 52, and transmitted through mirror 31. Lenses 51 and 52 form a first lens group. Laser light 61 transmitted through mirror 31 is further collected by lenses 53 and 54 and irradiated onto phosphor 41 on phosphor wheel 21 with a small spot diameter of about Φ1 mm.

[0040] Laser light 61 irradiated onto phosphor 41 of phosphor wheel 21 is converted into fluorescent light 71 and reflected toward the incident side of laser light 61 with a Lambertian distribution of light. Fluorescent light 71 is approximately collimated by lenses 53 and 54, and is reflected and transmitted by mirror 31. Lenses 53 and 54 constitute a third lens group. Colored light 81 reflected by mirror 31 is slightly focused by lens 55, which corrects the parallelism of the light, and passes through mirror 32 in a state of approximately parallel light. Colored light 81 is then focused by lens 56 and enters light uniformizing element 90.

[0041] Next, the red light path will be described. As shown in Fig. 5-2, laser light 62 emitted from laser light source 12 is collected by lens 57, approximately collimated by lens 58, and transmitted through mirror 32. Lenses 57 and 58 form a second lens group. Laser light 62 transmitted through mirror 32 is further collected by lenses 59 and 60 and irradiated onto phosphor 42 on phosphor wheel 22 with a small spot diameter of about Φ1 mm.

[0042] Laser light 62 irradiated onto phosphor 42 of phosphor wheel 22 is converted into fluorescent light 72 and reflected toward the incident side of laser light 62 with a Lambertian distribution of light. Fluorescent light 72 is approximately collimated by lenses 59 and 60, and is reflected and transmitted by mirror 32. Lenses 59 and 60 constitute a fourth lens group. Colored light 82 reflected by mirror 32 is collected by lens 56 and enters light homogenizing element 90. Note that the conversion of fluorescent light 72 to colored light 82 reduces the amount of light to less than half.

[0043] Next, the blue light path will be described. As shown in Fig. 5-3, laser light 63 emitted from laser light source 13 is approximately collimated by lens 50 and passes through mirror 31. After passing through mirror 31, laser light 63 is slightly condensed by lens 55, approximately collimated, and passes through mirror 32. After passing through mirror 32, laser light 63 is condensed by lens 56 and enters light uniformizing element 90.

[0044] As described above, in this embodiment, all light reflected by and transmitted through the mirrors 31 and 32 is substantially parallel light. Since the dichroic filter layers 36 of the mirrors 31 and 32 are designed to receive light at a predetermined angle of incidence, this configuration results in little loss of efficiency in the dichroic filter layers 36.

[0045] As described above, according to this embodiment, the mirrors 31 and 32, which are optical elements that guide the fluorescence 71 and 72 emitted from the phosphors 41 and 42 to the downstream optical system, are provided with the dichroic filter layer 36 that has the property of transmitting and reflecting a desired color, thereby enabling higher color purity.

[0046] Furthermore, according to this embodiment, the blue laser light emitted from laser light source 13 can be made to pass through mirrors 31 and 32, thereby achieving the most compact configuration. With such a configuration, the blue light can be combined simply by adding laser light source 13 while using mirrors 31 and 32 for generating fluorescent light 71 and fluorescent light 72 as they are (without changing the position or adding any other elements).

[0047] In this embodiment, the transmittance spectra of the fluorescent light and the dichroic filter layer 36 are as described above, but are not limited thereto. For example, if higher color purity is desired, the colored light 82 will have higher color purity if the region where the transmittance spectrum of the dichroic filter layer 36 is 0 is narrowed. In this way, the spectrum of the light source and the transmittance spectrum of the dichroic filter layer 36 can be designed as desired depending on the required light spectrum.

[0048] Here, Fig. 6 is a diagram schematically showing a modified example of the configuration of light source device 1. Fig. 6(a) is a diagram showing the configuration of light source device 1, and Fig. 6(b) is a diagram showing the transmittance spectrum of mirror 33. In the first embodiment, laser light 63 is transmitted through mirror 31 and mirror 32 and combined, but this method is not limited to this. For example, as shown in Fig. 6, the light may be combined by inserting mirror 33 (third optical element) that reflects blue laser light with a peak wavelength of 455 nm, for example, after mirror 32.

[0049] In the light source device 1 configured as above, the mirror 33 reflects only the blue light and transmits the other light. The mirror 33 transmits the colored light 81 and the colored light 82 and reflects the laser light 13, thereby combining the RGB light.

[0050] (Second embodiment) Next, a second embodiment will be described.

[0051] The second embodiment differs from the first embodiment in that the colored light 81 is configured to be a red light component and the colored light 82 is configured to be a green light component. In the following description of the second embodiment, the description of the same parts as in the first embodiment will be omitted, and only the parts that differ from the first embodiment will be described.

[0052] In the first embodiment, both mirror 31 and mirror 32 have the function of enhancing color purity, but this is not limited thereto, and both mirror 31 and mirror 32 do not necessarily have to have the function of enhancing color purity. For example, if the optical spectrum characteristics of dichroic filter layer 36 of mirror 31 are designed to transmit only blue light and reflect all other light, colored light 82 = fluorescent light 72, and although the color purity is low, the brightness is not reduced and the light can be used as illumination light. This example will be described in the second embodiment.

[0053] Here, Fig. 7 is a diagram schematically showing the configuration of light source device 1 according to the second embodiment, and Fig. 8 is a diagram showing an example of the optical spectrum of each light. As shown in Fig. 7, in this embodiment, phosphor 41 of phosphor wheel 21 is a red phosphor with a peak wavelength of 610 nm, and phosphor 42 of phosphor wheel 22 is a green phosphor with a peak wavelength of 515 nm.

[0054] 9 is a diagram showing an example of the transmittance spectrum of the dichroic filter layer 36 of the mirrors 31 and 32. In the transmittance spectrum shown in Fig. 9, light in the wavelength region where the vertical axis indicates 1 is transmitted, and light in the wavelength region where the vertical axis indicates 0 is reflected.

[0055] As shown in FIG. 9, in this embodiment, the optical spectrum characteristics of the transmittance of the dichroic filter layer 36 of the mirror 31 are designed to reflect green and red wavelengths from approximately 475 nm and transmit all other wavelengths, while the dichroic filter layer 36 of the mirror 32 is designed to reflect only green wavelengths from approximately 510 to 560 nm and transmit all other wavelengths.

[0056] 8 and 9, the dichroic filter layer 36 of the mirror 31 converts the optical spectrum of the fluorescence 71 into colored light 81 having an optical spectrum that cuts off the wavelength band of 475 nm or less. Also, as shown in Fig. 8 and 9, the dichroic filter layer 36 of the mirror 32 converts the optical spectrum of the fluorescence 72 into colored light 82 having an optical spectrum that cuts off the wavelength band other than 510 to 560 nm.

[0057] 9, in the light source device 1 of this embodiment having such a configuration, the fluorescence 71 emitted from the phosphors 41 of the phosphor wheel 21 is entirely reflected by the mirror 31 and directed toward the light uniformizing element 90. In this way, it is not necessary for both the mirror 31 and the mirror 32 to have the function of increasing color purity.

[0058] On the other hand, of the fluorescence 72 emitted from the phosphors 42 of the phosphor wheel 22, only colored light 82 is directed toward the light homogenizing element 90 by the mirror 32. The reflection wavelength range of the dichroic filter layer 36 of the mirror 32 is designed to be narrower than that of the first embodiment, so that the colored light 82 can have higher color purity.

[0059] As described above, according to this embodiment, color purity can be further increased.

[0060] (Third embodiment) Next, a third embodiment will be described.

[0061] The third embodiment differs from the first embodiment in the positional relationship between the laser light source 11 and the phosphor wheel 21, and in that the mirror 31 is tilted by 90 degrees. In the following description of the third embodiment, the description of the same parts as in the first embodiment will be omitted, and only the parts that differ from the first embodiment will be described.

[0062] 10 is a diagram schematically showing the configuration of a light source device 1 according to the third embodiment. Note that the spectrum of each light source and the transmittance spectrum of the dichroic filter layer 36 are the same as those in the first embodiment.

[0063] As shown in FIG. 10, the light source device 1 of this embodiment differs from the first embodiment in that the positional relationship between the laser light source 11 and the phosphor wheel 21 is reversed in the vertical direction in FIG. 10, and accordingly the mirror 31 is tilted by 90 degrees.

[0064] When irradiated with laser light, the phosphors 41 and 42 of the phosphor wheels 21 and 22 become extremely hot, which also increases the ambient temperature. As the temperature of the phosphors 41 and 42 of the phosphor wheels 21 and 22 increases, the luminous efficiency of the fluorescent light decreases.

[0065] In this regard, according to the light source device 1 of this embodiment, the two phosphor wheels 21 and 22 are provided apart from each other, which improves the cooling efficiency and the luminous efficiency of the fluorescent light.

[0066] In addition, the phosphor wheels 21 and 22 have a large outer circumference and are therefore dominant in the size of the optical system. In this regard, the light source device 1 according to this embodiment arranges the two phosphor wheels 21 and 22 facing each other rather than side-by-side, thereby making it possible to reduce the size of the optical system. In particular, miniaturization is important in a configuration using two phosphor wheels.

[0067] It goes without saying that the configuration of the light source device 1 is not limited to this, and the arrangement of the optical system can be freely changed depending on the cooling efficiency, mechanical configuration, and the like.

[0068] (Fourth embodiment) Next, a fourth embodiment will be described.

[0069] The fourth embodiment differs from the first embodiment in the positional relationship between the laser light source 11, the phosphor wheel 21, and the laser light source 13, and in the transmittance spectrum of the dichroic filter layer 36 of the mirror 31. In the following description of the fourth embodiment, the same parts as those in the first embodiment will be omitted, and only the differences from the first embodiment will be described.

[0070] Here, FIG. 11 is a diagram schematically showing the configuration of a light source device 1 according to the fourth embodiment, and FIG. 12 is a diagram showing an example of the optical spectrum of each light.

[0071] As shown in FIG. 11, the light source device 1 of this embodiment differs from the first embodiment in the positional relationship between the laser light source 11, the phosphor wheel 21, and the laser light source 13, and the transmittance spectrum of the dichroic filter layer 36 of the mirror 31.

[0072] 13 is a diagram showing an example of the transmittance spectrum of the dichroic filter layer 36 of the mirrors 31 and 32. In the transmittance spectrum shown in Fig. 13, light in the wavelength region where the vertical axis indicates 1 is transmitted, and light in the wavelength region where the vertical axis indicates 0 is reflected.

[0073] 13 , in this embodiment, mirror 31 transmits only green wavelengths and reflects the rest. Therefore, laser light 61 emitted from laser light source 11 is reflected by mirror 31 and enters phosphor 41 of phosphor wheel 21. Of fluorescence 71 emitted from phosphor 41 of phosphor wheel 21, only colored light 81 (green light) is transmitted by mirror 31, and the fluorescence 71 further passes through mirror 32 and heads toward light homogenizing element 90.

[0074] On the other hand, the laser light 63 emitted from the laser light source 13 is reflected by the mirror 31 and then passes through the mirror 32 toward the light uniformizing element 90 .

[0075] 12 and 13, the dichroic filter layer 36 of the mirror 31 converts the optical spectrum of the fluorescence 71 into colored light 81 having an optical spectrum that cuts off wavelengths other than those between 475 and 600 nm. Also, as shown in Fig. 12 and 13, the dichroic filter layer 36 of the mirror 32 converts the optical spectrum of the fluorescence 72 into colored light 82 having an optical spectrum that cuts off wavelengths equal to or shorter than 600 nm.

[0076] In this way, if the transmittance spectrum of the dichroic filter layer 36 is appropriately set, the laser light may be reflected by the mirror 31 and incident on the phosphor 41 of the phosphor wheel 21 .

[0077] As described above, according to this embodiment, by providing the two phosphor wheels 21 and 22 at a distance from each other, the cooling efficiency is improved, and the luminous efficiency of the fluorescent light can be improved. In addition, the mirror 31 can be a mirror that reflects blue light as well as a type that transmits blue light, which increases the degree of freedom in layout. For example, it becomes easier to install a cooling device that cools the laser light source.

[0078] In this embodiment, only the laser light 61 emitted from the laser light source 11 and the laser light 63 emitted from the laser light source 13 are reflected by the mirror, but the configuration may also be such that the laser light 62 emitted from the laser light source 12 is reflected by the mirror, and the configuration can be freely changed depending on conditions other than the light source device 1 (such as mechanical placement restrictions or restrictions due to the cooling device).

[0079] (Fifth embodiment) Next, a fifth embodiment will be described.

[0080] The fifth embodiment differs from the first embodiment in the mirror configuration and the transmittance spectrum of the dichroic filter layer. In the following description of the fifth embodiment, the same parts as those in the first embodiment will be omitted, and only the differences from the first embodiment will be described.

[0081] Here, Fig. 14 is a diagram schematically illustrating the configuration of light source device 1 according to the fifth embodiment, and Fig. 15 is a diagram illustrating an example of the optical spectrum of each light. The light source device 1 shown in Fig. 14 differs from the light source device 1 of the fourth embodiment in the configuration of the mirror and the transmittance spectrum of the dichroic filter layer.

[0082] 16 is a diagram showing an example of the transmittance spectrum of the dichroic filter layer 36 of the mirrors 31 and 32. In the transmittance spectrum shown in Fig. 16, light in the wavelength region where the vertical axis indicates 1 is transmitted, and light in the wavelength region where the vertical axis indicates 0 is reflected.

[0083] 16, in this embodiment, mirror 31 is composed of mirror 311 (first dichroic mirror) and mirror 312 (second dichroic mirror). Mirror 311 is designed to transmit blue to green light, and mirror 312 is designed to reflect only blue light.

[0084] 15 and 16, the dichroic filter layer 36 of the mirror 31 converts the optical spectrum of the fluorescence 71 into colored light 81 having an optical spectrum that cuts off wavelengths other than those between 475 and 600 nm. Also, as shown in Fig. 15 and 16, the dichroic filter layer 36 of the mirror 32 converts the optical spectrum of the fluorescence 72 into colored light 82 having an optical spectrum that cuts off wavelengths of 600 nm or less.

[0085] 17 is a diagram showing the overall configuration of light source device 1. As shown in FIG. 17, laser light 61 emitted from laser light source 31 is reflected by mirror 312 and enters phosphor 41 of phosphor wheel 21. A portion of fluorescence 71 emitted from phosphor 41 of phosphor wheel 21 passes through mirror 312.

[0086] Fluorescence 71 emitted from phosphor 41 of phosphor wheel 21 is approximately collimated by lenses 53 and 54 and travels toward mirror 311 with a beam width. Fluorescence 71 near the optical axis passes through mirror 312. Of the portion of fluorescence 71 that passes through mirror 312 and the remaining fluorescence 71, only colored light 81 is transmitted by mirror 312 and travels toward mirror 32. Colored light 81 passes through mirror 23 and travels toward light homogenizing element 90.

[0087] Laser light 63 emitted from the laser light source 13 is substantially collimated by the lens 50 and the lens 50a, passes through the mirror 311, and is reflected by the mirror 312. The laser light 63 reflected by the mirror 312 passes through the mirror 311 again toward the mirror 32, and then passes through the mirror 32 toward the light uniformizing element 90. As a result, the spectrum incident on the light uniformizing element 90 is equivalent to that of the first embodiment, etc. In this embodiment, an adjusting lens 110 is provided between the mirror 31 and the mirror 32, which adjusts the state of the fluorescent light 71 or colored light 81 emitted from the mirror 31 to substantially collimated light.

[0088] As described above, the mirror is not limited to being composed of a single element, but may be a combination of multiple mirrors. Also, the mirror may be configured, for example, by providing different dichroic filter layers on the surface of the same glass plate.

[0089] For example, a bandpass filter such as the transmittance spectrum of the dichroic filter layer 36 of the mirror 31 in the fourth embodiment may be more difficult to manufacture and more expensive than a lowpass filter or a highpass filter. According to this embodiment, a configuration using a lowpass filter and a highpass filter instead of a bandpass filter can be used, thereby reducing costs.

[0090] (Sixth embodiment) Next, a sixth embodiment will be described.

[0091] The sixth embodiment differs from the first to fifth embodiments in that the sixth embodiment is an image projection device including the light source device 1 of any one of the first to fifth embodiments. In the following description of the sixth embodiment, the description of the same parts as the first to fifth embodiments will be omitted, and only the parts that differ from the first to fifth embodiments will be described.

[0092] FIG. 18 is a schematic diagram showing the configuration of a projector 100 according to the sixth embodiment.

[0093] The projector (projection device) 100 includes a light source device 1, a light uniformizing element 90, an illumination optical system 111, an image forming element (image display element) 112, and a projection optical system 113.

[0094] The light source device 1 emits light containing wavelengths corresponding to the respective colors of RGB, for example.

[0095] The light uniformizing element 90 uniformizes the light emitted from the light source device 1 by mixing it. More specifically, the light uniformizing element 90 receives a light beam incident from its incident side surface, propagates it through its interior while repeatedly reflecting it, and emits it from its exit surface. The light uniformizing element 90 forms a uniform surface light source on its exit surface by internally reflecting the light beam incident from its incident side surface multiple times. Examples of the light uniformizing element 90 include a light tunnel with a hollow interior and four mirrors on the inner surface, a rod integrator formed into a prism made of a transparent material such as glass, and a fly's eye lens. For example, when a light tunnel is used as the light uniformizing element 90, the shape of the light tunnel exit is set to be approximately the same as the aspect ratio of the image forming element (image display element) 112, and the shape of the light tunnel exit is projected onto the surface of the image forming element (image display element) 112, thereby enabling efficient illumination of the surface of the image forming element (image display element) 112 without waste.

[0096] The illumination optical system 111 is illuminated approximately uniformly with the light homogenized by the light homogenizing element 90. The illumination optical system 111 has, for example, one or more lenses and one or more reflecting surfaces.

[0097] The image forming element (image display element) 112 has a light valve such as a digital micromirror device (DMD), a transmissive liquid crystal panel, a reflective liquid crystal panel, etc. The image forming element (image display element) 112 forms an image by modulating the light illuminated by the illumination optical system 111 (light from the light source optical system of the light source device 1).

[0098] The projection optical system 113 enlarges and projects the image formed by the image forming element (image display element) 112 onto a screen (projection surface). The projection optical system 113 has, for example, one or more lenses. The projection optical system 113 has a conjugate relationship such that the image on the surface of the image forming element (image display element) 112 is focused as an enlarged image at a desired position on the screen (projection surface), and therefore, the spatially modulated image is enlarged and projected onto the surface of the image forming element (image display element) 112.

[0099] As described above, according to this embodiment, the light source device 1 is used, so that a bright projector with good color purity can be obtained.

[0100] Although the above-described embodiments show preferred examples of the present invention, the present invention is not limited to those examples.

[0101] In particular, the specific shapes and numerical values ​​of each part illustrated in each of the above-mentioned embodiments are merely examples of the embodiments that may be implemented when carrying out the present invention, and the technical scope of the present invention should not be interpreted in a limited manner based on these.

[0102] As described above, the present invention is not limited to the details explained in the above-described embodiments, and can be modified as appropriate within the scope of the gist thereof. [Explanation of symbols]

[0103] 1 Light source device 11 First Light Source 12 Second Light Source 13 The Third Light Source 21 First wavelength conversion element 22 Second wavelength conversion element 31 First optical element 32 Second Optical Element 33 Third Optical Element 36 Conversion unit 41,42 Phosphors 51,52 First lens group 53,54 Third lens group 57,58 Second lens group 59,60 Fourth lens group 61 First excitation light 62 Second excitation light 63 The Third Colored Light 90 Light uniformizing element 100 Projection device 110 Adjustable Lens 112 Image display element 113 Projection optical system 311 First dichroic mirror 312 Second dichroic mirror [Prior art documents] [Patent documents]

[0104] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-116905 [Patent Document 2] U.S. Patent No. 8,840,253

Claims

1. a first light source that emits first excitation light; a second light source provided separately from the first light source and emitting second excitation light; a first wavelength conversion element that is excited by the first excitation light and emits first fluorescence; a second wavelength conversion element that is excited by the second excitation light and emits second fluorescence; a first optical element disposed on a path of the first fluorescent light; a second optical element disposed on a path of the second fluorescent light; an adjusting lens provided between the first optical element and the second optical element, which adjusts the state of the first fluorescent light or the first color light emitted from the first optical element to a substantially parallel light; Equipped with at least one of the first optical element and the second optical element has a conversion unit that converts the first fluorescence or the second fluorescence into color light having an optical spectrum in which a part of a wavelength band of an optical spectrum of at least one of the first fluorescence or the second fluorescence is cut by transmitting or reflecting the first fluorescence or the second fluorescence; A light source device characterized by:

2. A first light source that emits first excitation light; a second light source provided separately from the first light source and emitting second excitation light; a first wavelength conversion element that is excited by the first excitation light and emits first fluorescence; a second wavelength conversion element that is excited by the second excitation light and emits second fluorescence; a first optical element disposed on a path of the first fluorescent light; a second optical element disposed on a path of the second fluorescent light; Equipped with at least one of the first optical element and the second optical element has a conversion unit that converts the first fluorescent light or the second fluorescent light into color light having an optical spectrum in which a part of a wavelength band of an optical spectrum of at least one of the first fluorescent light or the second fluorescent light is cut by transmitting or reflecting the first fluorescent light or the second fluorescent light, The first optical element includes a first dichroic mirror and a second dichroic mirror. A light source device characterized by:

3. A first light source that emits first excitation light; a second light source provided separately from the first light source and emitting second excitation light; a first wavelength conversion element that is excited by the first excitation light and emits first fluorescence; a second wavelength conversion element that is excited by the second excitation light and emits second fluorescence; a first optical element disposed on a path of the first fluorescent light; a second optical element disposed on a path of the second fluorescent light; Equipped with at least one of the first optical element and the second optical element has a conversion unit that converts the first fluorescent light or the second fluorescent light into color light having an optical spectrum in which a part of a wavelength band of an optical spectrum of at least one of the first fluorescent light or the second fluorescent light is cut by transmitting or reflecting the first fluorescent light or the second fluorescent light, the second optical element combines either the first fluorescent light or a first colored light having an optical spectrum obtained by cutting a part of a wavelength band of the optical spectrum of the first fluorescent light, and either the second fluorescent light or a second colored light having an optical spectrum obtained by cutting a part of a wavelength band of the optical spectrum of the second fluorescent light, the amount of light is reduced to half or less by converting the second fluorescent light into the second color light; A light source device characterized by:

4. the second optical element combines either the first fluorescent light or a first colored light having an optical spectrum obtained by cutting a part of a wavelength band of the optical spectrum of the first fluorescent light, and either the second fluorescent light or a second colored light having an optical spectrum obtained by cutting a part of a wavelength band of the optical spectrum of the second fluorescent light.

3. The light source device according to claim 1, wherein:

5. the first excitation light is incident on the first wavelength conversion element via the first optical element, The second excitation light is incident on the second wavelength conversion element via the second optical element.

5. The light source device according to claim 1, wherein the light source device is a light source unit.

6. The first wavelength conversion element and the second wavelength conversion element include phosphors having different wavelengths.

6. The light source device according to claim 1, wherein the light source device is a light source unit.

7. the first wavelength conversion element comprises a green phosphor; The second wavelength conversion element comprises a yellow phosphor.

7. The light source device according to claim 6.

8. the first wavelength conversion element comprises a green phosphor; The second wavelength conversion element comprises a red phosphor.

7. The light source device according to claim 6.

9. The first wavelength conversion element and the second wavelength conversion element include phosphors of the same wavelength.

6. The light source device according to claim 1, wherein the light source device is a light source unit.

10. The first wavelength conversion element and the second wavelength conversion element include a yellow phosphor.

10. The light source device according to claim 9.

11. the amount of light is reduced to half or less by converting the second fluorescent light into the second color light; 5. The light source device according to claim 4.

12. the optical spectrum obtained by cutting a part of the wavelength band of the optical spectrum of the second fluorescence has a half-value on the short wavelength side of about 590 nm; 5. The light source device according to claim 3, wherein the light source device is a light source unit.

13. a third light source provided separately from the first light source and the second light source and emitting a third color light; 13. The light source device according to claim 1, wherein the light source device is a light source unit.

14. the third color light emitted from the third light source is transmitted through or reflected by the first optical element, and is combined with either the first fluorescent light or a first color light having an optical spectrum obtained by cutting a part of a wavelength band of the optical spectrum of the first fluorescent light; 14. The light source device according to claim 13.

15. the third color light emitted from the third light source is transmitted through or reflected by the second optical element, and is combined with either the second fluorescent light or second color light having an optical spectrum obtained by cutting a part of the wavelength band of the optical spectrum of the second fluorescent light; 14. The light source device according to claim 13.

16. a third optical element disposed on a path of the third color light; the third optical element combines the third color light with either the first fluorescent light or a first color light having an optical spectrum obtained by cutting a part of a wavelength band of the optical spectrum of the first fluorescent light, or either the second fluorescent light or a second color light having an optical spectrum obtained by cutting a part of a wavelength band of the optical spectrum of the second fluorescent light.

14. The light source device according to claim 13.

17. the first fluorescent light or the first colored light having an optical spectrum obtained by cutting a part of the wavelength band of the optical spectrum of the first fluorescent light is green light, the second fluorescent light or the second colored light having an optical spectrum obtained by cutting a part of the wavelength band of the optical spectrum of the second fluorescent light is red light, the third color light is blue light; 17. The light source device according to claim 13, wherein the light source device is a light source unit.

18. a first lens group that substantially collimates the first excitation light; a second lens group that substantially collimates the second excitation light; Equipped with the first excitation light is transmitted through or reflected by the first optical element in a substantially parallel state; the second excitation light is transmitted through or reflected by the second optical element in a substantially parallel state; 18. The light source device according to claim 1, wherein the light source device is a light source unit.

19. a third lens group that substantially collimates the first fluorescence emitted from the first wavelength conversion element; a fourth lens group that approximately collimates the second fluorescence emitted from the second wavelength conversion element; Equipped with the first fluorescent light is transmitted through or reflected by the first optical element in a substantially parallel state; the second fluorescent light is transmitted through or reflected by the second optical element in a substantially parallel state; 19. The light source device according to claim 1, wherein the light source device is a light source unit.

20. an adjusting lens provided between the first optical element and the second optical element, which adjusts the state of the first fluorescent light or the first color light emitted from the first optical element to a substantially parallel light; 20. The light source device according to claim 2, wherein the light source device is a light source unit.

21. The first optical element includes a first dichroic mirror and a second dichroic mirror.

21. The light source device according to claim 1, 3 or 20.

22. the first excitation light is reflected by the first dichroic mirror and enters the first wavelength conversion element; The first fluorescent light is incident on the first dichroic mirror and converted into the color light by the second dichroic mirror.

22. The light source device according to claim 2 or 21.

23. the first optical element, the second optical element, and the third optical element do not use a band-pass filter; 17. The light source device according to claim 16.

24. A light source device according to any one of claims 1 to 23; a light uniformizing element that uniformizes the light incident from the light source device and emits the uniform light; an image display element that modulates the light from the light uniformizing element to form an image; a projection optical system that enlarges and projects the image onto a projection surface; A projection device comprising:

Images