Image projection device

Abstract

To provide an image projection device capable of projecting an image that can be visually recognized easily even on a light place.SOLUTION: The image projection device according to one aspect of the disclosure comprises: a light source unit; an image display element modulating light emitted from the light source unit to display an image; and a projection optical system projecting the image displayed by the image display element. The light source unit emits light satisfying A>B and A>C, where A denotes radiation energy of light with wavelength of 510 nm or more and 610 nm or less; B denotes radiation energy of light with wavelength less than 510 nm; and C denotes radiation energy of light with wavelength exceeding 610 nm. The image projected by the projection optical system includes light satisfying A>B and A>C.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an image projection device. [Background technology]

[0002] 2. Description of the Related Art Image projection devices such as projectors that project monochrome images are known.

[0003] Also, an image projection device has been disclosed that uses Ye light having a wavelength range around 550 nm in order to increase the brightness of the projected image (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide an image projection device capable of projecting an image that is easily visible even in bright places. [Means for solving the problem]

[0005] An image projection device according to one embodiment of the present disclosure comprises a light source unit, an image display element that modulates light emitted from the light source unit to display an image, and a projection optical system that projects the image displayed by the image display element, wherein the light source unit emits light that satisfies A>B and A>C, where A is the radiant energy of light having a wavelength of 510 nm or more and 610 nm or less, B is the radiant energy of light having a wavelength less than 510 nm, and C is the radiant energy of light having a wavelength greater than 610 nm, and the image projected by the projection optical system also consists of light that satisfies A>B and A>C. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to provide an image projection device capable of projecting an image that is easily visible even in bright places. [Brief explanation of the drawings]

[0007] [Figure 1]1 is a schematic diagram showing the overall configuration of an image projection device according to a first embodiment of the present disclosure. [Figure 2] 1 is a schematic diagram showing a first example of the configuration of a light source unit included in an image projection device according to a first embodiment of the present disclosure. [Figure 3] 3 is a schematic diagram showing the configuration of a phosphor wheel included in the light source unit of FIG. 2, and is a plan view of the phosphor wheel as viewed from a direction along the rotation axis of the phosphor wheel. FIG. [Figure 4] FIG. 3 is a second schematic diagram showing the configuration of a phosphor wheel included in the light source unit of FIG. 2, and is a cross-sectional view of the phosphor wheel as viewed from a direction intersecting the rotation axis of the phosphor wheel. [Figure 5] 3 is a diagram showing the spectral distribution of light emitted from a phosphor wheel included in the light source unit of FIG. 2. FIG. [Figure 6] 4 is a schematic diagram showing a second example of the configuration of the light source unit included in the image projection device according to the first embodiment of the present disclosure. FIG. [Figure 7] 7 is a schematic diagram showing the configuration of a phosphor wheel provided in the light source unit of FIG. 6. FIG. [Figure 8] FIG. 2 is a diagram showing the ratio of the radiation intensity of yellow fluorescent light in each wavelength range of light projected from the image projection device according to the first embodiment of the present disclosure, and is a diagram showing the radiation intensity in the range of 510 nm to 610 nm. [Figure 9] FIG. 2 is a diagram showing the ratio of the radiation intensity of yellow fluorescent light in each wavelength range of light projected from the image projection device according to the first embodiment of the present disclosure, and is a diagram showing the radiation intensity in the range of 428 nm to 688 nm. [Figure 10] 1 is a schematic diagram illustrating a configuration of a projection optical system included in an image projection device according to a first embodiment of the present disclosure. [Figure 11] 1 is a schematic diagram showing the configuration of a plurality of lenses included in an image projection device according to a first embodiment of the present disclosure. [Figure 12] 3 is a diagram showing the relationship between the reflectance of a mirror included in the image projection device according to the first embodiment of the present disclosure and wavelength. FIG. [Figure 13] 4 is a diagram showing the relationship between the transmittance and wavelength of a lens included in the image projection device according to the first embodiment of the present disclosure. FIG. [Figure 14] FIG. 10 is a schematic diagram showing the configuration of a light source unit included in an image projection device according to a second embodiment of the present disclosure. [Figure 15] FIG. 10 is a schematic diagram showing the configuration of a stationary phosphor unit included in an image projection device according to a second embodiment of the present disclosure. [Figure 16] FIG. 10 is a schematic diagram showing the configuration of a light source unit included in an image projection device according to a third embodiment of the present disclosure. [Figure 17] FIG. 10 is a diagram showing the spectral distribution of light emitted from a light source unit included in an image projection device according to a third embodiment of the present disclosure. [Figure 18] FIG. 1 is a diagram illustrating color distribution per cycle in the DLP system. [Figure 19A] FIG. 1 is a schematic perspective view showing an example of the configuration of a wearable display device, which is an example of a projection device according to a conversion example. [Figure 19B] FIG. 10 is a diagram illustrating a partial configuration of a wearable display device according to a conversion example. [Figure 19C] FIG. 10 is a schematic diagram showing another example of the configuration of a wearable display device according to a conversion example. [Figure 19D] FIG. 10 is a diagram illustrating the configuration of a helmet equipped with a visor including a light guide plate in a wearable display device according to a conversion example. [Figure 19E] FIG. 10 is a schematic diagram showing yet another example configuration of a wearable display device according to a conversion example. [Figure 20A] FIG. 1 is a schematic diagram showing an example of an automobile equipped with a head-up display device, which is an example of a projection device according to a conversion example. [Figure 20B] FIG. 1 is a schematic diagram illustrating an example of a head-up display device according to a conversion example. [Figure 20C] FIG. 10 is a schematic diagram showing yet another configuration example of a head-up display device according to a conversion example. DETAILED DESCRIPTION OF THE INVENTION

[0008] An image projection device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. However, the following embodiments are merely examples of image projection devices that embody the technical concepts of the present embodiments, and are not intended to be limiting.

[0009] Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of components described in the embodiments of the present disclosure are not intended to limit the scope of the present disclosure, but are merely illustrative examples. The sizes, positional relationships, etc. of components shown in each drawing may be exaggerated for clarity. In the following description, the same names and symbols indicate the same or similar components, and detailed descriptions will be omitted as appropriate.

[0010] [First embodiment] <Configuration of image projection device according to first embodiment of the present disclosure> (Overall composition) 1 is a schematic diagram showing an example of the overall configuration of an image projection device 1 according to a first embodiment of the present disclosure. FIG. 1 shows the inside of the image projection device 1 in a see-through manner.

[0011] The image projection device 1 includes a light source unit 20, an image display element 50 that displays an image by modulating light emitted from the light source unit 20, and a projection optical system 60 that projects the image displayed by the image display element 50. The image projection device 1 enlarges and projects the image displayed by the image display element 50 onto a screen 70 by the projection optical system 60.

[0012] Here, for example, image projection devices such as monochrome projectors that project monochrome images are known. In recent years, image projection devices have increasingly been used for purposes such as guide displays and drawing projection, which emphasize brightness over the color gamut. For such applications, image projection devices are required to have improved luminosity and brightness, making projected images more visible even in brightly lit areas.

[0013] In the first embodiment of the present disclosure, the light source unit 20 emits light that satisfies A>B and A>C, where A is the radiant energy of light with a wavelength of 510 nm or more and 610 nm or less, B is the radiant energy of light with a wavelength less than 510 nm, and C is the radiant energy of light with a wavelength greater than 610 nm. The image projected by the projection optical system 60 is also made up of light that satisfies A>B and A>C.

[0014] Light that satisfies A>B and A>C has high luminosity. For example, light with a wavelength of 510 nm or greater and 610 nm or less has the same power (radiant flux "W"), but the degree of brightness "lm" perceived by the human eye varies depending on the wavelength, with the 555 nm wavelength perceived as the brightest. Relative luminosity is the ratio of brightness at other wavelengths to the perceived brightness at 555 nm, taken as 100%. According to JIS Z 8785:2019, the relative luminosity is 50% or greater for wavelengths between 510 nm and 610 nm, with 510 nm and 610 nm roughly corresponding to the inflection points of the curve. Image projection device 1 emits light that satisfies A>B and A>C and projects an image composed of light that satisfies A>B and A>C, thereby projecting an image that is easy to see. For example, the image projection device 1 can project an image that is easy to see by emitting light that satisfies A>B and A>C and projecting an image made of light with a high relative luminosity factor at a wavelength of 510 nm or more and 610 nm or less. As described above, the first embodiment of the present disclosure can provide an image projection device 1 that can project an image that is easy to see even in bright places.

[0015] From the viewpoint of projecting an image that is easily visible even in bright places, it is more preferable that the light source unit 20 emits light that satisfies A>B+C, and even more preferable that it emits light that satisfies at least one of A≧2B and A≧2C.

[0016] The image projection device 1 shown in FIG. 1 includes a housing 10, a light uniformizing element 30, and an illumination optical system 40. The housing 10 houses a light source unit 20, a light uniformizing element 30, an illumination optical system 40, an image display element 50, and a projection optical system 60. The light uniformizing element 30 uniformizes the light emitted from the light source unit 20 by mixing the light. The light uniformizing element 30 can be, for example, a light tunnel formed by combining four mirrors, a glass rod, a microlens array, or a diffuser. The illumination optical system 40 substantially uniformly illuminates the image display element 50 with the light uniformized by the light uniformizing element 30. The illumination optical system 40 includes, for example, one or more lenses or one or more reflective surfaces. The image display element 50 is, for example, a light valve such as a digital micromirror device (DMD), a transmissive liquid crystal panel, a reflective liquid crystal panel, or a mask substrate (a photomask, a plate with holes where light is desired to pass). The DMD is an image display element in which the micromirrors of each pixel are tilted by switching each pixel ON (lighted) or OFF (lighted out), and the light from the ON-state micromirrors is directed to the projection optical system 60. The projection optical system 60 has one or more lenses and enlarges and projects the image formed by the image display element 50 onto the screen 70.

[0017] (light source unit 20) (Example 1) A first example of the configuration of the light source unit 20 included in the image projection device 1 according to the first embodiment of the present disclosure will be described with reference to FIGS. 2 to 5. FIG. 2 is a schematic diagram showing a first example of the configuration of the light source unit 20 included in the image projection device 1 according to the first embodiment of the present disclosure. FIG. 3 is a first schematic diagram showing the configuration of the phosphor wheel 27 included in the light source unit 20 of FIG. 2, and is a plan view of the phosphor wheel 27 viewed from a direction along the rotation axis of the phosphor wheel 27. FIG. 4 is a second schematic diagram showing the configuration of the phosphor wheel 27 included in the light source unit 20 of FIG. 2, and is a cross-sectional view of the phosphor wheel 27 viewed from a direction intersecting the rotation axis of the phosphor wheel 27. FIG. 5 is a diagram showing the spectral distribution of light emitted from the phosphor wheel 27 included in the light source unit 20 of FIG. 2.

[0018] The light source unit 20 includes an excitation light source 21 and a phosphor wheel 27 that receives light emitted from the excitation light source 21 and emits light with a wavelength different from that of the light emitted from the excitation light source 21. In the example shown in FIG. 2, the light source unit 20 includes a collimator lens 22, a first optical system 23, a polarizing beam splitter 24, a quarter-wave plate 25, a second optical system 26, and a condenser lens 28. The excitation light source 21, the collimator lens 22, the first optical system 23, the polarizing beam splitter 24, the quarter-wave plate 25, the second optical system 26, the phosphor wheel 27, and the condenser lens 28 are arranged in this order in the light propagation direction. For example, the components of the light source unit 20 excluding the excitation light source 21 constitute a "light source optical system." The first optical system 23 includes a first lens 23A and a second lens 23B. The second optical system 26 includes a third lens 26A and a fourth lens 26B.

[0019] Excitation light source 21 has a plurality of semiconductor lasers as the plurality of solid-state light sources. By using a plurality of solid-state light sources as excitation light source 21, it is possible to increase the light extraction efficiency from light source unit 20 while miniaturizing light source unit 20. In excitation light source 21 shown in FIG. 2, six semiconductor lasers are arranged in four rows in the depth direction. Within an imaginary side plane intersecting the light emission direction of excitation light source 21, 6 × 4 = 24 semiconductor lasers are aligned two-dimensionally. Each of the plurality of semiconductor lasers included in excitation light source 21 emits, for example, light in the blue band (blue laser light) with a center wavelength of 455 nm in emission intensity as excitation light P for exciting phosphors provided in fluorescent region 27D of phosphor wheel 27.

[0020] The excitation light P emitted from each of the multiple semiconductor lasers included in the excitation light source 21 is linearly polarized light with a constant polarization state and is coherent light. The multiple semiconductor lasers included in the excitation light source 21 are arranged so that the light is S-polarized with respect to the incident surface of the polarizing beam splitter 24. Note that the excitation light P emitted from each light source of the excitation light source 21 may be light of a wavelength that can excite the phosphor in the fluorescent region 27D of the phosphor wheel 27, and is not limited to light in the blue wavelength range. Furthermore, the number of light sources in the excitation light source 21 is not limited to 24, but may be 1 to 23 or less, or 25 or more. The excitation light source 21 can be configured, for example, as a light source array in which multiple light sources are arranged in an array on a substrate, and the specific form thereof is flexible.

[0021] There are provided 24 collimator lenses 22 corresponding to the 24 light sources of the excitation light source 21. Each collimator lens 22 adjusts the excitation light B emitted by each light source of the excitation light source 21 to become approximately parallel light. The number of collimator lenses 22 only needs to correspond to the number of light sources of the excitation light source 21, and can be increased or decreased according to an increase or decrease in the number of light sources of the excitation light source 21.

[0022] The polarizing beam splitter 24 is coated so as to reflect S-polarized light in the wavelength band of the excitation light P guided from the first optical system 23, while transmitting P-polarized light in the wavelength band of the excitation light P guided from the first optical system 23 and the fluorescent light Y, which is yellow fluorescence from the phosphor wheel 27. In the example shown in FIG. 2, a flat polarizing beam splitter 24 is used, but a prism-type polarizing beam splitter 24 can also be used. In the example shown in FIG. 2, the polarizing beam splitter 24 reflects S-polarized light in the wavelength band of the excitation light P and transmits P-polarized light. However, the polarizing beam splitter 24 may be configured to reflect P-polarized light in the wavelength band of the excitation light P and transmit S-polarized light.

[0023] The quarter-wave plate 25 is disposed with its optical axis tilted by 45 degrees with respect to the linearly polarized light of the excitation light P reflected by the polarizing beam splitter 24. The quarter-wave plate 25 converts the excitation light P reflected by the polarizing beam splitter 24 from linearly polarized light to circularly polarized light.

[0024] The second optical system 26 has a positive power overall, and includes, in order from the excitation light source 21 side to the phosphor wheel 27 side, a third lens 26A which is a positive lens and a fourth lens 26B which is also a positive lens. The second optical system 26 converges and guides the excitation light P that has been converted into circularly polarized light by the quarter-wave plate 25 and is incident thereon to the phosphor wheel 27. The excitation light P guided from the second optical system 26 is incident on the phosphor wheel 27.

[0025] The phosphor wheel 27 corresponds to a wavelength conversion unit that receives light emitted from the excitation light source 21 and emits light with a wavelength different from that of the light emitted from the excitation light source 21. As shown in FIGS. 3 and 4, the phosphor wheel 27 has a disk member 27A and a drive motor 27C that rotates the disk member 27A around a rotation axis 27B. The disk member 27A may be, for example, a transparent substrate or a metal substrate. However, the present invention is not limited to this. The metal substrate may be, for example, an aluminum substrate.

[0026] Most of the circumferential area of phosphor wheel 27 is divided into fluorescent regions 27D. In this embodiment, the fluorescent region preferably has an angular range greater than 270 degrees. In the example shown in FIG. 3, fluorescent region 27D is 360 degrees. Fluorescent region 27D is configured by laminating, from the bottom to the top, a reflective coating 27D1, a phosphor layer 27D2, and an anti-reflection coating 27D3.

[0027] The reflective coating 27D1 has the property of reflecting light in the wavelength region of the fluorescent light Y emitted by the phosphor layer 27D2. If the disk member 27A is made of a metal substrate with high reflectivity, the reflective coating 27D1 can be omitted. It is also possible to give the disk member 27A the function of the reflective coating 27D1.

[0028] The phosphor layer 27D2 may be, for example, a phosphor material dispersed in an organic or inorganic binder, a phosphor material crystallized directly, or a rare earth phosphor such as Ce:YAG. The wavelength band of the fluorescent light Y emitted by the phosphor layer 27D2 may be, for example, a yellow or green wavelength band. In this specification, a case where fluorescent light Y having a yellow wavelength band is used will be described as an example. The wavelength conversion unit is not limited to the phosphor wheel 27, and a phosphor, a nonlinear optical crystal, or the like may also be used.

[0029] The anti-reflection coating 27D3 has the property of preventing light from being reflected on the surface of the phosphor layer 27D2.

[0030] A reflective coating 27E1 having the property of reflecting light in the wavelength region of the excitation light P guided from the second optical system 26 is laminated on the excitation light reflection region 27E. If the disk member 27A is made of a metal substrate with high reflectivity, the reflective coating 27E1 can be omitted. Alternatively, the disk member 27A can be given the function of the reflective coating 27E1.

[0031] By rotating disk member 27A using drive motor 27C, the irradiation position of excitation light P on phosphor wheel 27 moves over time. As a result, a portion of excitation light P incident on phosphor wheel 27 is converted into fluorescent light Y having a wavelength different from that of excitation light P in fluorescent region (wavelength conversion region) 27D and emitted.

[0032] 5, most of the light emitted from light source unit 20 has a wavelength in the range of 510 nm to 610 nm, and is yellow light with high visibility. Other wavelength ranges are also included in the visible light range of 428 nm to 688 nm. Therefore, light source unit 20 can provide image projection device 1 with light with excellent visibility.

[0033] The term "majority" in this specification indicates that A>B and A>C, where A(W) is the radiant energy in the wavelength region of green to yellow light corresponding to wavelengths of 510 nm or more and 610 nm or less, B(W) is the radiant energy of light with wavelengths less than 510 nm, and C(W) is the radiant energy of light with wavelengths longer than 610 nm.

[0034] 2, excitation light P incident on fluorescent region 27D of phosphor wheel 27 is converted into fluorescent light Y and emitted. This fluorescent light Y is made into approximately parallel light by second optical system 26, passes through quarter-wave plate 25, transmits polarizing beam splitter 24, passes through condenser lens 28, and is incident on light homogenizing element 30.

[0035] The fluorescent light Y is guided from the light uniformizing element 30 through the illumination optical system 40 to the image display element 50, where it forms an image. The image is then enlarged and projected onto a screen 70 by the projection optical system 60, thereby obtaining the image formed by the fluorescent light Y, i.e., a yellow monochromatic image. While this embodiment uses a yellow phosphor as an example, a green monochromatic image can be obtained if a green phosphor is used as the phosphor. A monochromatic image is an image expressed by the shading (light and shade) of monochromatic light with a certain spectral distribution. The shading can be generated by controlling the brightness of each pixel using the image display element 50. A monochromatic image can also be called a monochrome image.

[0036] Here, we will calculate the simplest configuration for a full-color display using a single-panel DMD system, using an image projection device that outputs the minimum monochrome colors R (red), G (green), and B (blue). The proportion of each color when displaying an R, G, and B image in one frame is assumed to be 360 degrees, which is one cycle of the color wheel, and the image projection device divides each color into three equal parts, each at 120 degrees.

[0037] Each color is projected as a single color for a duration of 120 degrees. However, in reality, the illumination light crosses the color boundaries due to its spread (spot size), resulting in color mixing. To account for this, the signal for this portion of the projector is often turned off to account for the so-called spoke time (SP). Since the typical SP time is between 5 and 15 degrees, for example, considering a 10-degree spot size, an image projection device designed to achieve equal angles for each color is designed to have 110 degrees for each RGB color, with three 10-degree SPs, for a total of 360 degrees. In other words, the ratio of R:G:B:SP is 11:11:11:3. If the total radiant energy is 1, then R is 11 / 36, G is 11 / 36, B is 11 / 36, and SP is 3 / 36. Consider a projector designed for a brightness of 5,000 lumens.

[0038] Since the RGB monochromatic colors are distributed at wavelengths other than the dominant wavelength of each monochromatic color, they cannot be calculated simply. However, in order to explain the effects of this embodiment, we will simplify the calculation and, based on the luminosity characteristics, assume that B and R are each 0.2, while G is 1. In other words, the 5000 lumens of each color is the sum of the 4583 lumens output by excluding 3 / 36, or 1 / 12, of the SP, which is the sum of the RGB monochromatic colors. In other words, R and B are each 655 lumens, and G is 3273 lumens.

[0039] In this embodiment, monochromatic light is projected, i.e., a single light in the wavelength range from green to yellow is output as light, so all of the R and B time can be allocated to the G region. Since the relative luminosity of B and R is approximately 0.2, if the same amount of radiant energy as R and B is output as G, the human eye will perceive it as five times brighter than R and B. In other words, it is five times 655 lumens, so 3274 lumens from R to G, 3274 lumens from B to G, and the same 3274 lumens from G, added to the original 3274 lumens for G, the total brightness is 3274 lumens x 3 = 9822 lumens.

[0040] Since all SP components can be projected in green, at least 417 lumens, or 1 / 12 of 5,000 lumens, is added, resulting in 10,238 lumens, further improving brightness. In practice, there are limitations in actual use, such as setting a time for the DMD to be turned off (turned off). However, it is clear that using a single color, particularly the green to yellow range, can have a significant effect on improving brightness. In this way, by having an image projection device designed for the desired brightness to output full color primarily project light in the green wavelength range, it is possible to achieve a nearly two-fold improvement in brightness.

[0041] (Example 2) A second example of the configuration of the light source unit included in the image projection device according to the first embodiment of the present disclosure will be described with reference to Figures 6 to 10. Note that the same names and symbols as those in the already described embodiments indicate the same or similar members or configurations, and detailed descriptions will be omitted as appropriate. This also applies to the examples and embodiments described below.

[0042] Fig. 6 is a schematic diagram showing a second example of the configuration of the light source unit 20 included in the image projection device 1 according to the first embodiment of the present disclosure. Fig. 7 is a schematic diagram showing an example of the configuration of the phosphor wheel 27 included in the light source unit 20 of Fig. 6. Fig. 8 is a diagram showing the ratio of the radiant intensity of yellow fluorescent light in each wavelength range of light projected from the image projection device 1 according to the first embodiment of the present disclosure, and is a diagram showing the radiant intensity of 510 nm or more and 610 nm or less. Fig. 9 is a diagram showing the ratio of the radiant intensity of yellow fluorescent light in each wavelength range of light projected from the image projection device 1 according to the first embodiment of the present disclosure, and is a diagram showing the radiant intensity of 428 nm or more and 688 nm or less.

[0043] The second example shown in FIGS. 6 to 8 differs from the first example shown in FIGS. 2 to 5 mainly in that it has a dichroic mirror 29 that reflects blue light and transmits fluorescent light Y.

[0044] Let us consider the case where fluorescent light Y is output by irradiating a phosphor with a wavelength band from green to yellow using a blue light source. In this case, there are four monochromatic colors: R (red), G (green), B (blue), and Y (yellow). For example, when white is output by mixing the monochromatic colors R, G, B, and Y, the ratio of the monochromatic colors (monochromatic luminance ratio) is R:G:B:Y=0.08:0.3:0.03:0.3. Note that the difference of 0.29 between the sum of R, G, B, and Y and 1 represents the spoke time. In terms of luminous flux, if the brightness of the image projection device 1 is 5,000 lumens, the brightness of R is 400 lumens, the brightness of G is 1,500 lumens, the brightness of B is 150 lumens, and the brightness of Y is 500 lumens. On the other hand, the radiant energy ratio is R:G:B:Y = 0.10:0.16:0.26:0.17 (spoke time is 0.30).

[0045] 6, if the total of 0.1 + 0.16 + 0.26 = 0.52 for R, G, and B other than Y is allocated to Y, the result is 0.52 / 0.17 x 1500 = 4588, which is an increase of 4588 lumens. In other words, the brightness of the image projection device 1 becomes 1500 + 4588 = 6088, which is an increase of 6088 lumens.

[0046] In terms of the radiant energy ratio, the Y component is 0.36, with 0.1 for R and 0.26 for B. Furthermore, doubling each of the R and B colors results in 0.2 or 0.52, which is at least 0.52 for the Y component. Furthermore, if the 0.3 for the spoke time is allocated to the Y radiant output, the result is 0.3 / 0.17 x 1500 = 2647, which is an additional 2647 lumens. Furthermore, the result is 6088 + 2048 = 8735 lumens, an improvement of 1.75 times, further increasing the radiant energy ratio by more than 2x. If almost all of the B is converted to the Y component, the ratio of the Y component to the B component becomes infinitely large.

[0047] In the case of fluorescent light Y in this embodiment, as shown in FIG. 8, energy E1 between 510 nm and 610 nm is 77%, energy E2 below 510 nm is 4%, and energy E3 above 610 nm is 19%.

[0048] Since E1 (77%) > E2 (4%) and E1 (77%) > E3 (19%), and E1 (77%) > E2 (4%) + E3 (19%), it can be said that "the majority of the emitted light is green to yellow light with a wavelength of 510nm to 610nm, which has a high visibility range." Furthermore, since E1 (77%) > 2 x E2 (19% x 2) and E1 (77%) > 2 x E3 (4% x 2), it can be said that it is monochromatic light in a more desirable wavelength range.

[0049] Furthermore, as shown in Figure 9, the radiant energy in the visible light range of 428 nm to 688 nm accounts for 98% of the total energy of fluorescent light Y, so it can be said that the wavelength of fluorescent light Y emitted from the light source unit is within the visible light wavelength range, and most of the radiant energy contributes to visibility. In other words, fluorescent light Y is an efficient light for providing brighter, easier-to-view projected images.

[0050] (Projection optical system 60) A projection optical system 60 provided in the image projection device according to the first embodiment of the present disclosure will be described with reference to Fig. 10 and Fig. 11. Fig. 10 is a schematic diagram showing an example of the configuration of the projection optical system 60 provided in the image projection device 1 according to the first embodiment of the present disclosure. Fig. 11 is a schematic diagram showing an example of the configuration of a plurality of lenses 51 provided in the image projection device 1 according to the first embodiment of the present disclosure.

[0051] Fig. 10 shows the image display element 50 and the projection optical system 60. Fig. 11 shows an enlarged view of the image display element 50 shown in Fig. 10 and a plurality of lenses 51 included in part of the refractive optical system 61 in the projection optical system 60. The image display element 50 has an image forming unit LV as a part that forms the image to be projected. The image formed in the image forming unit LV of the image display element 50 is illuminated by illumination light from the illumination optical system 40.

[0052] The following description will be given assuming that the image display element 50 is a DMD, and that the image display element does not have the ability to emit light itself. The projection optical system 60 according to this embodiment is not limited to this configuration. A self-illuminating element capable of emitting light to generate an image may also be used, or a light valve other than a DMD may also be used. Furthermore, the combination of the projection optical system 60 may further include a lighting device, a mirror, dustproof glass, etc., as long as it includes the image display element 50 and the projection optical system 60.

[0053] As shown in FIG. 10, a parallel plate CG is disposed near the image display element 50 on the image forming unit LV side. The parallel plate CG is a light-transmitting flat plate and serves as a cover glass (sealing glass) for the image forming unit LV. The projection optical system 60 enlarges and projects an image formed by the image forming unit LV onto a screen 70 (see FIG. 1), and includes, in order from the image forming unit LV to the screen 70, a refractive optical system 61 including multiple lenses 51 and a reflective optical system 64 including a reflective surface with power. The multiple lenses 51 shown in FIG. 11 have an aperture stop S. Light from the image forming unit LV that has passed through the parallel plate CG passes through the multiple lenses 51 along the optical path shown in FIG. 10, passes through the refractive optical system 61, and is projected onto the screen 70 via a reflective optical system 64 including a reflective mirror 62, a curved mirror 63, etc.

[0054] For example, by designing the reflectance characteristics of the reflective mirror 62 and the curved mirror 63 so that they have high reflectance in the wavelength band of the projected light, it is possible to realize an image projection device that is brighter and has better visibility. Furthermore, it is known that the image quality deteriorates, particularly with the curved mirror 63, when unreflected light generates heat and deforms the mirror. Improving the reflectance helps to suppress this, resulting in a projected image that is easier to see.

[0055] (Mirrors and lenses included in the image projection device 1) Fig. 12 is a diagram showing an example of the relationship between the reflectance and wavelength of a mirror included in the image projection device 1 according to the first embodiment of the present disclosure. Fig. 13 is a diagram showing the relationship between the transmittance and wavelength of a lens included in the image projection device 1 according to the first embodiment of the present disclosure.

[0056] FIG. 12 shows the reflectance of a mirror designed to achieve high reflectance across the wavelength range of light projected from the image projection device 1. While it would be ideal to use a mirror with 100% reflectance across all wavelength ranges, this is difficult. It is necessary to design or select a mirror by determining which wavelength ranges require high reflectance and which wavelength ranges require sacrifice. The reflectance characteristics shown in FIG. 12 indicate that the reflectance in the wavelength range from 510 nm to 550 nm, where the intensity was highest in the spectral distribution of the fluorescent light Y shown in FIG. 5, is higher than the reflectance at 450 nm or 650 nm. In other words, the projection optical system 60 includes a mirror, and the reflectance of the mirror for light with a wavelength of 510 nm to 610 nm is higher than the reflectance of the mirror for light with a wavelength of 450 nm or 650 nm. Using such a mirror enables the provision of brighter projected images with better visibility. In addition, the reflectance of the mirror included in at least one of the projection optical system 60 and the light source unit 20 for light having a wavelength of 510 nm or more and 610 nm or less may be higher than the reflectance of the mirror for light having a wavelength of 450 nm or 650 nm, without being limited to the mirror included in the projection optical system 60.

[0057] To realize a mirror having the characteristics shown in Fig. 12, it is necessary to devise a reflective coating for the mirror. For example, one method is to vapor-deposit aluminum onto a resin substrate and then coat the surface with an enhanced reflection film. However, other methods may also be used, such as using silver instead of aluminum. A mirror having the characteristics shown in Fig. 12 can be applied to the projection optical system 60, mirrors in the light source unit 20, micromirrors in the image display element 50, etc.

[0058] Here, of the radiant energy of light projected as an image displayed by the image display element 50, the radiant energy in the green to yellow range of 510 nm to 610 nm is defined as A', and the radiant energy outside the green to yellow range of 510 nm to 610 nm is defined as (B'+C'). In this case, when a mirror having the characteristics shown in FIG. 12 is used in the projection optical system 60, A / (B+C)<=A' / (B'+C') By configuring it in this way, it is possible to realize an image projection device 1 that efficiently projects light in the wavelength band of 510 nm or more and 610 nm or less, which has high visibility. Note that A / (B+C)<=A' / (B'+C') means that the loss of radiant energy in the range of 510 nm or more and 610 nm or less in the projection optical system 60, etc. is smaller than in other ranges.

[0059] The transmittance characteristics of glass materials used in the lenses of the image projection device 1 include, for example, glass materials S1 and S2 shown in FIG. 13. For a wavelength of 460 nm, the transmittance of glass material S1 is higher than that of glass material S2. For wavelengths of 550 nm and 650 nm, the transmittance of glass material S2 is higher than that of glass material S1. In other words, the projection optical system 60 includes a lens, and the transmittance of the lens for light with a wavelength of 510 nm or more and 610 nm or less is higher than the transmittance of the lens for light with a wavelength of 450 nm. For example, a glass material such as glass material S2, which has high transmittance for 550 nm light, which has high luminosity, is suitable for use in the projection optical system 60. Using lenses made of such glass material S2 can achieve a bright image projection device with good visibility. In addition, the transmittance of the lens included in at least one of the projection optical system 60 and the light source unit 20 for light having a wavelength of 510 nm or more and 610 nm or less may be higher than the transmittance of the lens for light having a wavelength of 450 nm or 650 nm, without being limited to the lens included in the projection optical system 60.

[0060] [Second embodiment] Next, an image projection device according to a second embodiment of the present disclosure will be described with reference to Fig. 14 and Fig. 15. Fig. 14 is a schematic diagram showing an example of the configuration of a light source unit 20 included in the image projection device according to the second embodiment of the present disclosure. Fig. 15 is a schematic diagram showing an example of the configuration of a stationary phosphor unit 261 included in the image projection device according to the second embodiment of the present disclosure.

[0061] As shown in FIG. 14, the image projection device of this embodiment differs from the image projection device of the first embodiment of the present disclosure in that it has a stationary phosphor unit 261 that is not rotated, a first cooler 212 that cools the excitation light source 21 in the light source unit 20, and a second cooler 262 that cools the stationary phosphor unit 261.

[0062] Fig. 15 shows the stationary phosphor unit 261 viewed from a direction perpendicular to the incident direction of the blue light. As shown in Fig. 15, the stationary phosphor unit 261 is configured by stacking phosphor 261b, which is a wavelength conversion member, on a reflective member 261a that reflects excitation light. For example, when viewed from the incident direction of the blue light, the reflective member 261a and phosphor 261b have an approximately rectangular outer edge shape. The phosphor 261b is applied onto the reflective member 261a.

[0063] The stationary phosphor unit 261 corresponds to a wavelength conversion unit that receives light emitted from an excitation light source and emits light with a wavelength different from the wavelength of the light emitted from the excitation light source. When blue light is incident on the stationary phosphor unit 261, the blue light acts as excitation light for the phosphor 261b and is wavelength-converted by the phosphor 261b. As a result, the blue light becomes fluorescent light Y that includes a yellow wavelength range with a center of emission intensity of 550 [nm], for example, and is subjected to Lambertian reflection by the action of the phosphor 261b and the reflecting member 261a.

[0064] A portion of the blue light incident on the stationary phosphor unit 261 does not act as excitation light and is reflected by the reflecting member 261a. Therefore, when blue light is incident on the stationary phosphor unit 261, the blue light and fluorescent light Y are simultaneously emitted. The fluorescent light Y emitted from the stationary phosphor unit 261 corresponds to "light that satisfies A>B and A>C, where A is the radiant energy of light having a wavelength of 510 nm or more and 610 nm or less, B is the radiant energy of light having a wavelength less than 510 nm, and C is the radiant energy of light having a wavelength greater than 610 nm."

[0065] The stationary phosphor unit 261 does not rotate, unlike the phosphor wheel 27 in the first embodiment. A second cooler 262 can be connected to the surface of this reflecting member 261a opposite to the surface on which the phosphor 261b is laminated. By connecting the second cooler 262, heat generation by the phosphor 261b can be suppressed, and high wavelength conversion efficiency can be expected, thereby providing a brighter and easier-to-view image projection device.

[0066] The light source unit 20 shown in FIG. 14 is a package in which multiple excitation light sources 21 are housed in a light source housing 211. For example, by arranging a first cooler 212 on the side of the light source unit 20 opposite to the surface from which excitation light is emitted, heat generation from the excitation light sources 21 can be suppressed. A metal member or a carbon member with excellent heat conductivity can be used for the first cooler 212. Since the excitation light sources 21 have temperature characteristics in which the amount of light emitted increases as the temperature decreases, cooling using such a first cooler 212 increases the light emission efficiency. This makes it possible to realize an image projection device 1 that is brighter and easier to view.

[0067] [Third embodiment] An image projection device according to a third embodiment of the present disclosure will be described with reference to Fig. 16 to Fig. 18. Fig. 16 is a schematic diagram showing an example of the configuration of light source unit 20 included in the image projection device according to the third embodiment of the present disclosure. Fig. 17 is a diagram showing the spectral distribution of light emitted from light source unit 20 included in the image projection device according to the third embodiment of the present disclosure.

[0068] The image projection device according to this embodiment differs from the image projection device according to the first embodiment in that the light source unit 20 emits green light G.

[0069] 16, green light G emitted from each of the multiple excitation light sources 21 is adjusted by the corresponding collimator lens 22 to become approximately parallel light, then condensed by the first lens 23A, and enters the light uniformizing element 30. The behavior of the light after exiting the light uniformizing element 30 is the same as that shown in FIG. 1. The green light G is guided from the light uniformizing element 30 through the illumination optical system 40 to the image display element 50. The image projection device according to this embodiment can display a green monochrome image by enlarging and projecting an image displayed on the image display element 50 onto a screen 70 using the projection optical system 60.

[0070] The excitation light source 21 that emits green light G can be, for example, one that emits laser light with a wavelength of 525 nm, one that emits laser light with a wavelength of 532 nm, one that emits laser light with a wavelength of 518 nm, or a combination of these. By combining green excitation light sources 21 with different wavelengths, the green hue can be adjusted according to the color or material of the screen 70 or the viewer's preference, thereby further improving visibility. The excitation light source 21 is not limited to one that emits green light G, and an image projection device with excellent visibility can be realized as long as the wavelength is 510 nm or more and 610 nm or less.

[0071] The excitation light source 21 in this embodiment emits green light G in an extremely narrow wavelength band, as shown in the spectral distribution of Fig. 17. Since all of the light energy of green light G is included in the region with high relative luminosity, energy A between 510 nm and 610 nm is 100%, energy B below 510 nm is 0%, and energy C above 610 nm is 0%. This makes it possible to realize an image projection device that is even brighter and has better visibility.

[0072] Since A(100%) > B(0%) and A(100%) > C(0%), and A(100%) > B(0%) + C(0%), this can be said to be "light that satisfies A>B and A>C, where A is the radiant energy of light with a wavelength of 510 nm or greater and 610 nm or less, B is the radiant energy of light with a wavelength less than 510 nm, and C is the radiant energy of light with a wavelength greater than 610 nm." Furthermore, since A(100%) > 2B(0% x 2) and A(100%) > 2 x C (0% x 2), this can be said to be monochromatic light with a more desirable wavelength band. The brightness of the image projection device according to this embodiment is further improved when it is equipped with the first cooler 212 shown in FIG. 14.

[0073] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0074] For example, in the embodiment, the brightness of the projection light can be improved. Here, FIG. 18 is a diagram illustrating color distribution per cycle in the DLP system. In a DLP image projection device, each color is projected in a time-division manner, so that wavelengths with high luminosity are projected for only a portion of one cycle (one frame). In the example shown in FIG. 18, they are projected for one-fourth of one frame. To project a bright image, it is ideal that the time during which light with wavelengths with high luminosity is emitted is 100% of one cycle (one frame). By projecting a monochromatic image, the time during which light with wavelengths with high luminosity is emitted can be 100% of one cycle (one frame).

[0075] All ordinal numbers, quantitative numbers, and other figures used in the description of the embodiments are provided as examples to specifically explain the technology of the present disclosure, and the present disclosure is not limited to the illustrated figures. Furthermore, the connection relationships between components are provided as examples to specifically explain the technology of the present disclosure, and do not limit the connection relationships that realize the functions of the present disclosure.

[0076] Various examples of applications of the image projection device according to the embodiment will be described below.

[0077] <Head-mounted display device> FIG. 19A is a schematic perspective view showing an example of the configuration of a wearable display device 600, which is an example of a projection device, and FIG. 19B is a schematic view showing a part of the wearable display device 600 shown in FIG. 19A.

[0078] The illustrated wearable display device 600 is a head-mounted display that can be worn on a human head, such as a head-mounted display device shaped like glasses or goggles. In Fig. 19A, the wearable display device 600 is composed of a front panel 600a and temples 600b, which are provided approximately symmetrically on the left and right sides. The front panel 600a can be composed of, for example, a light guide plate 610, and the optical system, control device, etc. can be built into the temples 600b.

[0079] Fig. 19B is a diagram illustrating a portion of the configuration of the wearable display device 600. Note that Fig. 19B illustrates the configuration for the left eye, but the wearable display device 600 has a similar configuration for the right eye.

[0080] The wearable display device 600 includes, for example, a control device 11, a light source unit 100 which is the light source device of this embodiment, a light intensity adjustment unit 607, a movable device 13 having a reflective surface 14, a light guide plate 610, and a half mirror 620.

[0081] The light source unit 100 is a unit that includes a laser light source, a collimator lens, a dichroic mirror, and the like, enclosed in an optical housing.

[0082] The light from the light source unit 100 is adjusted in intensity by the light intensity adjustment section 607 and then enters the movable device 13. The movable device 13 moves the reflecting surface 14 in the X and Y directions based on a signal from the control device 11, thereby two-dimensionally scanning the light from the light source unit 100. The drive control of this movable device 13 is performed, for example, in synchronization with the emission timing of the laser light source provided in the light source unit 100.

[0083] The scanning light from the movable device 13 enters the light guide plate 610. The light guide plate 610 reflects the scanning light on its inner wall surface and guides it to the half mirror 620. The light guide plate 610 is made of a resin or the like that is transparent to the wavelength of the scanning light.

[0084] The half mirror 620 reflects the light from the light guide plate 610 toward the rear side of the wearable display device 600 and emits the light toward the eye 630 of the wearer of the wearable display device 600. The half mirror 620 has, for example, a free-form surface shape. An image formed by the scanning light is formed on the retina of the wearer's eye 630 by reflection from the half mirror 620. Alternatively, an image is formed on the retina of the wearer's eye 630 by reflection from the half mirror 620 and the lens effect of the crystalline lens in the eyeball. Furthermore, spatial distortion of the image is corrected by reflection from the half mirror 620. The wearer can observe an image formed by the light scanned in the XY directions. The use of the half mirror 620 allows the wearer to observe an image formed by light from the external world and an image formed by the scanning light in a superimposed manner. Note that a mirror may be provided instead of the half mirror 620 to eliminate light from the external world and enable observation of only the image formed by the scanning light.

[0085] 19C is a schematic diagram showing another example configuration of the wearable display device 600. The control device 1000 included in the wearable display device 600 is installed in each of the left and right temples 600b so as to correspond to the light source units 100 and movable devices 13 incorporated in each of the left and right temples 600b, as shown in FIG.

[0086] In addition, the control device 1000 may be installed in a central position of the wearable display device 600 (such as the midpoint between the left and right light guide plates 610), as shown in Figure 19C (b), and the light source units 100 and movable devices 13 incorporated in each of the left and right temples 600b may be controlled by a common control device 1000.

[0087] 19D, the wearable display device 600 may be in the form of a helmet 650 equipped with a visor 640 including a light guide plate 610. In this case, the light source unit 100, the light amount adjuster 607, the movable device 13, the reflective surface 14, and the control device 11 may be built into the helmet 650 as shown in the figure.

[0088] 19E is a schematic diagram showing yet another example configuration of a wearable display device 600. The illustrated wearable display device 600 is a neckband-type display device that can be worn around a person's neck or shoulders.

[0089] 19E(a), a wearer 660 wearing a wearable display device 600 is sitting in front of a display 670 placed on a desk D. The display 670 communicates with the wearable display device 600 via short-range wireless communication such as Bluetooth, and outputs a display signal. The wearable display device 600 also includes a projector 680, which projects an image K of an input keyboard onto the upper surface of the desk D, as shown in FIG. 19E(b).

[0090] The wearable display device 600 may be equipped with a camera in addition to the projector 680. The camera detects the movement of the fingers of the wearer 660 on the image K of the input keyboard projected on the desk D. Information on the detection result of the camera is transmitted to, for example, a control device of the wearable display device 600, and the control device determines which key of the input keyboard the wearer 660 has pressed based on the information received from the camera, and causes the display 670 to display information corresponding to the determination result.

[0091] <Head-up display device> Fig. 20A is a schematic diagram showing an example of an automobile 400 equipped with a head-up display device 700, which is an example of a projection device, and Fig. 20B is a schematic diagram showing an example of the head-up display device 700. The head-up display device 700 is, for example, a projection device that projects an image by optical scanning.

[0092] 20A, the head-up display device 700 is installed near the windshield 401 of the automobile 400. Projection light L emitted from the head-up display device 700 is reflected by the windshield 401 and directed toward an observer (driver 402) who is the user. This allows the driver 402 to view an image projected by the head-up display device 700 as a virtual image. Note that a combiner may be installed on the inner wall surface of the windshield, and the user may view a virtual image by the projection light reflected by the combiner.

[0093] 20B, head-up display device 700 includes light source unit 100, which is the light source device of this embodiment. Light emitted from light source unit 100 passes through, for example, light amount adjustment unit 707 and is then deflected by movable device 13 having reflective surface 14. The deflected light then passes through a projection optical system made up of free-form surface mirror 709, intermediate screen 710, and projection mirror 711, and is projected onto the screen.

[0094] The head-up display device 700 projects an intermediate image displayed on an intermediate screen 710 onto a windshield 401 of an automobile 400, thereby allowing a driver 402 to visually recognize the intermediate image as a virtual image.

[0095] The light emitted from light source unit 100 has its light intensity adjusted by light intensity adjustment section 707, and then is two-dimensionally scanned by movable device 13 having reflecting surface 14. Projection light L scanned two-dimensionally by movable device 13 is reflected by free-form surface mirror 709, where distortion is corrected, and then focused on intermediate screen 710 to display an intermediate image. Intermediate screen 710 is composed of a microlens array in which microlenses are arranged two-dimensionally, and magnifies the projection light L incident on intermediate screen 710 in microlens units.

[0096] The movable device 13 reciprocates the reflective surface 14 in two axial directions, thereby two-dimensionally scanning the projection light L incident on the reflective surface 14. The drive control of this movable device 13 is performed, for example, in synchronization with the light emission timing of the laser light source provided in the light source unit 100.

[0097] 20C, the head-up display device 700 includes an imager 200 and a free-form surface mirror 709. Of these, the imager 200 includes a light source unit 100 which is the light source device of this embodiment.

[0098] Light emitted from the light source unit 100 passes through, for example, an illumination system 201 and then is irradiated onto an image forming unit 202. The image forming unit 202 includes a light modulation unit such as a micromirror device or a liquid crystal panel. A control device 203 controls the light emission drive of the light source provided in the light source unit 100 and the drive of the light modulation unit provided in the image forming unit 202. An image generated by the image forming unit 202 is formed as an intermediate image on an intermediate screen 205 by a projection lens 204.

[0099] The head-up display device 700 reflects the image formed on the intermediate screen 205 onto the windshield 401 of the vehicle via the free-form surface mirror 709, allowing the driver 402 to view the virtual image I. Note that a folding mirror may be placed between the free-form surface mirror 709 and the windshield 401 as required for layout purposes.

[0100] The intermediate screen 205 is configured, for example, with a microlens array in which microlenses are arranged two-dimensionally. In this embodiment, the microlens array is used to control the viewing angle characteristics, thereby enhancing the viewing angle characteristics of the image projected onto the intermediate screen 205 and generating a brighter virtual image.

[0101] The projection device is not limited to the configurations of the projector, wearable display device, and head-up display device described above. The projection device is not limited to being attached to an automobile or a human body, but may also be mounted on, for example, a railway vehicle, an airplane, or a ship. The projection device may also be mounted on a mobile object such as a robot capable of autonomous or remote-controlled movement, a drone, or an unmanned aerial vehicle, or a non-mobile object such as a work robot that operates a manipulator or other drive object without moving from its location.

[0102] Aspects of the present disclosure are, for example, as follows. <1> An image projection device comprising: a light source unit; an image display element that modulates the light emitted from the light source unit to display an image; and a projection optical system that projects the image displayed by the image display element, wherein the light source unit emits light that satisfies A>B and A>C, where A is the radiant energy of light having a wavelength of 510 nm or more and 610 nm or less, B is the radiant energy of light having a wavelength less than 510 nm, and C is the radiant energy of light having a wavelength greater than 610 nm, and the image projected by the projection optical system is also made up of light that satisfies A>B and A>C. <2> the light source unit emits light that satisfies A>B+C; <1> 2. The image projection device according to claim 1, <3> the light source unit emits light that satisfies either A≧2B or A≧2C; <1> or the above <2> 2. The image projection device according to claim 1, <4> The wavelength of the light emitted from the light source unit is within the wavelength band of visible light. <1> From the above <3> The image projection device according to any one of the above items. <5> At least one of the projection optical system and the light source unit includes a mirror, and the reflectance of the mirror for light having a wavelength of 510 nm or more and 610 nm or less is higher than the reflectance of the mirror for light having a wavelength of 450 nm or 650 nm. <1> From the above <4> The image projection device according to any one of the above items. <6> At least one of the projection optical system and the light source unit includes a lens, and the transmittance of the lens for light having a wavelength of 510 nm or more and 610 nm or less is higher than the transmittance of the lens for light having a wavelength of 450 nm. <1> From the above <5> The image projection device according to any one of the above items. <7> the light source unit includes a solid-state light source; <1> From the above <6> The image projection device according to any one of the above items. <8> the light source unit includes an excitation light source and a wavelength conversion unit that receives light emitted from the excitation light source and emits light having a wavelength different from the wavelength of the light emitted from the excitation light source, <1> From the above <7> The image projection device according to any one of the above items. <9> a first cooler for cooling the excitation light source; <8> 2. The image projection device according to claim 1, <10> a second cooler for cooling the wavelength conversion unit, the wavelength conversion unit being a stationary phosphor unit that is not rotated; <8> 2. The image projection device according to claim 1, [Explanation of symbols]

[0103] 1. Image projection device 10. Cabinet 20 Light source unit 21 Excitation light source 22 Collimator lens 23 First Optical System 23A 1st lens 23B Second lens 24 Polarizing Beam Splitter 25 1 / 4 wave plate 26 Second Optical System 26A Third lens 26B 4th lens 27 Phosphor Wheel 27A Disc member 27B Rotating shaft 27D Fluorescent Area 28 Condenser Lens 29 Dichroic Mirror 30 Light uniformizing element 40 Illumination optical system 50 Image display element 51 Multiple Lenses 60 Projection optical system 61 Refractive Optics 62 Reflective mirror 63 Curved Mirror 64 Reflective optical system 70 screens 101 Upper Ray 102 Chief ray 211 Light source housing 212 First Cooler 261 Stationary Phosphor Unit 261a Reflective member 261b Phosphor 262 Second Cooler B Excitation light CG parallel plate LV image forming section S aperture stop S1, S2 Glass material Y fluorescent light [Prior art documents] [Patent documents]

[0104] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-033086

Claims

1. A light source unit; an image display element that displays an image by modulating the light emitted from the light source unit; a projection optical system that projects the image displayed by the image display element, the light source unit emits light that satisfies A>B and A>C, where A is the radiant energy of light having a wavelength of 510 nm or more and 610 nm or less, B is the radiant energy of light having a wavelength less than 510 nm, and C is the radiant energy of light having a wavelength greater than 610 nm; The image projected by the projection optical system is also made of light that satisfies A>B and A>C.

2. 2. The image projection device according to claim 1, wherein the light source unit emits light that satisfies A>B+C.

3. 2. The image projection device according to claim 1, wherein the light source unit emits light that satisfies at least one of A.gtoreq.2B and A.gtoreq.2C.

4. The image projection device of claim 1 , wherein the wavelength of the light emitted from said light source unit is within the wavelength band of visible light.

5. At least one of the projection optical system and the light source unit includes a mirror, 2. The image projection device according to claim 1, wherein the reflectance of the mirror to light having a wavelength of 510 nm or more and 610 nm or less is higher than the reflectance of the mirror to light having a wavelength of 450 nm or 650 nm.

6. At least one of the projection optical system and the light source unit includes a lens, 2. The image projection device according to claim 1, wherein the transmittance of said lens for light having a wavelength of 510 nm or more and 610 nm or less is higher than the transmittance of said lens for light having a wavelength of 450 nm.

7. The image projection device of claim 1 , wherein the light source unit includes a solid-state light source.

8. The light source unit is an excitation light source; 2. The image projection device according to claim 1, further comprising: a wavelength conversion unit that receives the light emitted from the excitation light source and outputs light having a wavelength different from the wavelength of the light emitted from the excitation light source.

9. 9. The image projection device according to claim 8, further comprising a first cooler that cools the excitation light source.

10. a second cooler for cooling the wavelength conversion unit; 9. The image projection device according to claim 8, wherein the wavelength conversion unit is a stationary phosphor unit that is not driven to rotate.

Images