Image projection apparatus

Abstract

The invention relates to an image projection device, and aims to provide an image projection device capable of projecting an image convenient to recognize in a bright place. The image projection apparatus includes: a light source unit; an image display element for modulating the light emitted from the light source unit and then displaying an image; and a projection optical system for projecting the image displayed by the image display element, the light source unit emitting light satisfying A > B and A > C when the radiant energy of light having a wavelength of 510-610 nm is set as A, the radiant energy of light having a wavelength of less than 510 nm is set as B, and the radiant energy of light having a wavelength of more than 610 nm is set as C, the image projected by the projection optical system is also formed by light satisfying A > B and A > C.

Description

Technical Field

[0001] The present invention relates to an image projection device. Background Art

[0002] Image projection devices such as projectors that project monochrome images are already known.

[0003] On the other hand, in order to improve the brightness of a projected image, an image projection device using Ye light having a wavelength range of around 550 nm is conventionally disclosed (for example, see Japanese Patent Application Publication No. 2013-033086). Summary of the Invention

[0004] An object of the present invention is to provide an image projection device capable of projecting an image that is easily recognizable in a bright place.

[0005] An image projection device involved in one embodiment of the present invention comprises: a light source unit; an image display element for modulating light emitted from the light source unit to display an image; and a projection optical system for projecting the image displayed by the image display element. When the radiation energy of light with a wavelength of 510 nm to 610 nm is set to A, the radiation energy of light with a wavelength less than 510 nm is set to B, and the radiation energy of light with a wavelength greater than 610 nm is set to C, the light source unit emits light satisfying A>B and A>C, and the image projected by the projection optical system is also formed by light satisfying A>B and A>C.

[0006] The present invention has the effect of providing an image projection device capable of projecting an easily recognizable image in a bright place. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is an overall schematic diagram of an image projection device according to a first embodiment of the present invention.

[0008] Figure 2 It is a schematic diagram of a first example of a light source unit included in the image projection apparatus according to the first embodiment of the present invention.

[0009] Figure 3 yes Figure 2 The schematic diagram of the fluorescent substance wheel included in the light source unit is a top view of the fluorescent substance wheel as seen in the direction of the rotation axis of the fluorescent substance wheel.

[0010] Figure 4 yes Figure 2 The second schematic diagram of the fluorescent substance wheel included in the light source unit is a cross-sectional view of the fluorescent substance wheel as viewed in a direction intersecting the rotation axis of the fluorescent substance wheel.

[0011] Figure 5 yes Figure 2Spectral distribution diagram of light emitted from the phosphor wheel included in the light source unit.

[0012] Figure 6 It is a schematic diagram of a second example of a light source unit included in the image projection apparatus according to the first embodiment of the present invention.

[0013] Figure 7 yes Figure 6 Schematic diagram of a phosphor wheel included in a light source unit.

[0014] Figure 8 This is a distribution diagram of the radiation intensity of yellow fluorescence in each wavelength region of light projected from the image projection apparatus according to the first embodiment of the present invention, showing the radiation intensity in the region of 510 nm to 610 nm.

[0015] Figure 9 This is a distribution diagram of the radiation intensity of yellow fluorescence in each wavelength region of light projected by the image projection apparatus according to the first embodiment of the present invention, showing the radiation intensity in the range of 428 nm to 688 nm.

[0016] Figure 10 It is a schematic diagram of a projection optical system included in the image projection device according to the first embodiment of the present invention.

[0017] Figure 11 It is a schematic diagram of a plurality of lenses included in the image projection device according to the first embodiment of the present invention.

[0018] Figure 12 This is a diagram showing the relationship between the reflectivity and wavelength of the reflecting mirror included in the image projection apparatus according to the first embodiment of the present invention.

[0019] Figure 13 This is a diagram showing the relationship between the transmittance of the lens included in the image projection device according to the first embodiment of the present invention and the wavelength.

[0020] Figure 14 It is a schematic diagram of a light source unit included in an image projection apparatus according to a second embodiment of the present invention.

[0021] Figure 15 It is a schematic diagram of a stationary fluorescent unit included in an image projection apparatus according to a second embodiment of the present invention.

[0022] Figure 16 It is a schematic diagram of a light source unit included in an image projection apparatus according to a third embodiment of the present invention.

[0023] Figure 17 This is a spectral distribution diagram of light emitted from a light source unit included in an image projection device according to a third embodiment of the present invention.

[0024] Figure 18 This is a color distribution diagram for each cycle of the DLP method.

[0025] Figure 19A This is an oblique view of a projection device involved in the transferred use case, that is, a wearable device.

[0026] Figure 19B This is a partial schematic diagram of a wearable display device involved in the transfer use case.

[0027] Figure 19C This is a schematic diagram of another wearable display device involved in the transferred use case.

[0028] Figure 19D This is a schematic diagram of a helmet having a visor including a light guide plate in a wearable display device involved in a transfer use case.

[0029] Figure 19E This is a schematic diagram of another wearable display device involved in the transferred use case.

[0030] Figure 20A This is a schematic diagram of an automobile equipped with a head-mounted display device as an example of a projector device used in an application.

[0031] Figure 20B This is a schematic diagram of a head-up display device involved in the transfer use case.

[0032] Figure 20C This is a schematic diagram of another head-up display device involved in the transferred use case.

[0033] Explanation of symbols

[0034] 1 Image projection device

[0035] 10 Housing

[0036] 20 light source units

[0037] 21 Excitation light source

[0038] 22 Collimating lens

[0039] 23 First Optical System

[0040] 23A First lens

[0041] 23B Second lens

[0042] 24 Polarization beam splitter

[0043] 25 1 / 4 wave plate

[0044] 26 Second optical system

[0045] 26A third lens

[0046] 26B fourth lens

[0047] 27 Phosphor Wheel

[0048] 27A Disc assembly

[0049] 27B Rotation axis

[0050] 27D fluorescent area

[0051] 28 Condenser lens

[0052] 29 Dichroic Mirror

[0053] 30 Light homogenization element

[0054] 40 Illumination Optical System

[0055] 50 Image display components

[0056] 51 multiple lenses

[0057] 60 Projection Optical System

[0058] 61 Refractive Optical System

[0059] 62 Reflector

[0060] 63 Curved Mirror

[0061] 64 Reflective Optical System

[0062] 70 screens

[0063] 101 Upper Light

[0064] 102 Main Ray

[0065] 211 light source housing

[0066] 212 First Cooler

[0067] 261 stationary phosphor unit

[0068] 261a Reflective components

[0069] 261b phosphor

[0070] 262 Second cooler

[0071] B Excitation light

[0072] CG parallel plate

[0073] LV image forming unit

[0074] S-iris

[0075] S1, S2 glass material Y fluorescence DETAILED DESCRIPTION

[0076] The following will describe in detail an image projection device according to an embodiment of the present invention with reference to the accompanying drawings. The following embodiments are examples for specifically embodying the technical concept of the image projection device according to the present embodiment and do not constitute a limitation to the present invention.

[0077] The sizes, materials, shapes, and relative arrangements of components described in the embodiments of the present invention, unless otherwise specified, do not limit the scope of the present invention to these sizes, materials, shapes, and relative arrangements; they are merely illustrative. For clarity, the sizes and positional relationships of components shown in the drawings may be exaggerated. Furthermore, in the following description, identical names and symbols represent identical or homogeneous components, and repeated descriptions will be omitted.

[0078] [First embodiment]

[0079] <Configuration of Image Projection Device According to First Embodiment of the Present Invention>

[0080] Overall composition

[0081] Figure 1 It is a schematic diagram showing an example of the overall structure of the image projection device 1 according to the first embodiment of the present invention. Figure 1 It is a perspective view of the interior of the image projection device 1 .

[0082] The image projection device 1 includes a light source unit 20, an image display element 50 that forms an image using modulated 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 using the projection optical system 60.

[0083] Known image projection devices include, for example, monochrome projectors that project monochrome images. In recent years, demand for image projection devices has been increasing for applications such as guidance displays and graphic projection, which prioritize brightness over color gamut. These applications require improved visibility and brightness, ensuring that projected images are easily visible even in brightly lit areas.

[0084] In the first embodiment of the present invention, when the radiant energy of light with a wavelength of 510 nm to 610 nm is set to A, the radiant energy of light with a wavelength less than 510 nm is set to B, and the radiant energy of light with a wavelength greater than 610 nm is set to C, the light source unit 20 emits light that satisfies A>B and A>C. The image projected by the projection optical system 60 is also formed by light that satisfies A>B and A>C.

[0085] Light that satisfies A>B and A>C is light with high visibility. For example, light between 510nm and 610nm satisfies A>B and A>C. Even if it is light of the same power (radiant flux "W"), the degree of brightness "lm" perceived by the human eye will vary depending on the wavelength, with light at 555nm being the brightest. Assuming that the brightness at 555nm is 100%, the brightness of other wavelengths expressed as a ratio is the spectral luminous efficiency. According to JISZ8785:2019, within the wavelength range between 510nm and 610nm, the spectral luminous efficiency is 50% or more, and 510nm and 610nm are roughly located at the inflection point of the curve. The image projection device 1 can project an easily recognizable image by emitting light that satisfies A>B and A>C and projecting an image formed by light that satisfies A>B and A>C. For example, the image projection device 1 can project an easily recognizable image by emitting light that satisfies A>B and A>C and projecting an image formed by light having a high spectral luminous efficiency of 510 nm or more and 610 nm or less. As described above, the first embodiment of the present invention can provide an image projection device 1 that can project an easily recognizable image even in bright places.

[0086] From the perspective of projecting an easily recognizable image even in a bright place, the light source unit 20 preferably emits light satisfying A>(B+C), and more preferably emits light satisfying at least one of A≥2B and A≥2C.

[0087] Figure 1 The image projection device 1 shown includes a housing 10, a light homogenizing element 30, and an illumination optical system 40. The housing 10 houses a light source unit 20, the light homogenizing element 30, the illumination optical system 40, an image display element 50, and a projection optical system 60. The light homogenizing element 30 homogenizes the light emitted from the light source unit 20 by mixing the light. The light homogenizing element 30 can be formed using, for example, a light tunnel comprising four reflective mirrors, a glass rod, a microlens array, a diffuser, or the like. The illumination optical system 40 illuminates the image display element 50 substantially uniformly with the light homogenized by the light homogenizing 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 DMD (Digital Mirror Device), a transmissive liquid crystal panel, a reflective liquid crystal panel, or a mask substrate (a plate with holes formed in areas where light is desired to pass, i.e., a photomask). The DMD is an image display element that operates by switching each pixel on (lit) or off (extinguished), tilting the micromirrors in each pixel, and then directing light from the micromirrors in the on state to the projection optical system. The projection optical system 60 includes one or more lenses and magnifies the image formed by the image display element 50 and projects it onto the screen 70.

[0088] Light source unit 20

[0089] -First example-

[0090] See also Figures 2 to 5 Next, a configuration example of the light source unit 20 included in the image projection apparatus 1 according to the first embodiment of the present invention will be described. Figure 2 1 is a schematic diagram showing a configuration of an example of the light source unit 20 included in the image projection apparatus 1 according to the first embodiment of the present invention. Figure 3 yes Figure 2 The first schematic diagram of the structure of the fluorescent substance wheel 27 included in the light source unit 20 is a top view of the fluorescent substance wheel 27 viewed along the direction of the rotation axis of the fluorescent substance wheel 27. Figure 4 yes Figure 2 The second schematic diagram of the structure of the fluorescent substance wheel 27 included in the light source unit 20 is a cross-sectional view of the fluorescent substance wheel 27 as viewed in a direction intersecting the rotation axis of the fluorescent substance wheel 27 . Figure 5 It is from Figure 2 Spectral distribution diagram of light emitted from the fluorescent wheel 27 included in the light source unit 20.

[0091] The light source unit 20 includes an excitation light source 21 and a fluorescent wheel 27. When the light emitted by the excitation light source 21 is incident on the fluorescent wheel 27, the fluorescent wheel 27 emits light of a wavelength different from that of the light emitted by the excitation light source 21. Figure 2 In the example shown, the light source unit 20 includes a collimating 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, collimating lens 22, first optical system 23, polarizing beam splitter 24, quarter-wave plate 25, second optical system 26, fluorescent wheel 27, and condenser lens 28 are arranged in this order along the direction of light propagation. For example, the components of the light source unit 20 other than the excitation light source 21 constitute the "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.

[0092] The excitation light source 21 includes a plurality of semiconductor lasers as a plurality of solid light sources. By using a plurality of solid light sources as the excitation light source 21, the light source unit 20 can be miniaturized while improving the light extraction efficiency of the light source unit 20. Figure 2In the illustrated excitation light source 21, six semiconductor lasers are arranged in four rows in the depth direction. In other embodiments, additional semiconductor lasers are sometimes arranged in rows along the depth direction. For example, in an embodiment in which four semiconductor lasers are included in each row arranged along an imaginary side surface intersecting the light emission direction of the excitation light source 21, 6×4=24 semiconductor lasers are arranged two-dimensionally within an imaginary side surface intersecting the light emission direction of the excitation light source 21 in which 6×4=24 semiconductor lasers are arranged as a two-dimensional array.

[0093] The plurality of semiconductor lasers included in the excitation light source 21 each emits light (blue laser light) in a blue band with a central wavelength of 455 nm, for example, as excitation light P that excites the phosphor provided in the phosphor region 27D of the phosphor wheel 27 .

[0094] The excitation light P emitted by each of the multiple semiconductor lasers in the excitation light source 21 is linearly polarized light with a fixed polarization state, and is coherent light. The multiple semiconductor lasers in the excitation light source 21 are configured to become S-polarized light relative to the incident plane of the polarization beam splitter 24. The excitation light P emitted by each light source of the excitation light source 21 only needs to be light of a wavelength that can excite the phosphor in the fluorescent area 27D of the phosphor wheel 27, and is not limited to light in the blue band. The number of light sources of the excitation light source 21 is not limited to 24, and can be more than 1 and less than 23, or more than 25. The excitation light source 21 can be configured as a light source array in which multiple light sources are arranged in an array shape on a substrate, and its specific form has a degree of freedom.

[0095] Twenty-four collimating lenses 22 are provided to correspond to the 24 light sources of the excitation light sources 21. Each collimating lens 22 is adjusted so that the excitation light B emitted by each light source of the excitation light sources 21 becomes substantially parallel light. The number of collimating lenses 22 only needs to correspond to the number of light sources in the excitation light sources 21, and can be increased or decreased accordingly.

[0096] The polarization beam splitter 24 is coated to reflect the S-polarized light in the wavelength band of the excitation light P guided by the first optical system 23, while allowing the P-polarized light in the wavelength band of the excitation light P guided by the first optical system 23 and the yellow fluorescence, i.e., fluorescence Y, emitted by the fluorescence wheel 27 to pass through. Figure 2 In the example of , a flat plate polarization beam splitter 24 is used, but a prism type polarization beam splitter 24 may also be used. Figure 2 In the example shown, the polarization beam splitter 24 reflects S-polarized light in the wavelength band of the excitation light P and transmits P-polarized light. However, the reverse may be true, whereby the polarization beam splitter 24 reflects P-polarized light in the wavelength band of the excitation light P and transmits S-polarized light.

[0097] The quarter-wave plate 25 is arranged so that its optical axis is tilted by 45 degrees with respect to the linearly polarized light of the excitation light P reflected by the polarization beam splitter 24. The quarter-wave plate 25 converts the excitation light P reflected by the polarization beam splitter 24 from linearly polarized light to circularly polarized light.

[0098] The second optical system 26 has positive optical power as a whole and comprises, in order from the excitation light source 21 toward the phosphor wheel 27, a third lens 26A (a positive lens) and a fourth lens 26B (a positive lens). The second optical system 26 converges the incident excitation light P, which has been converted into circularly polarized light by the quarter-wave plate 25, and simultaneously guides it toward the phosphor wheel 27. The excitation light P guided by the second optical system 26 enters the phosphor wheel 27.

[0099] The phosphor wheel 27 corresponds to a wavelength conversion unit, into which the light emitted from the excitation light source 21 is incident, and then emits light having a wavelength different from that of the light emitted from the excitation light source 21. Figure 3 and Figure 4 As shown, the fluorescent wheel 27 includes a disk member 27A and a drive motor 27C that drives the disk member 27A to rotate about a rotation axis 27B. The disk member 27A may be made of, for example, a transparent substrate or a metal substrate, but is not limited thereto. The metal substrate may be an aluminum substrate, for example.

[0100] Most of the circumferential direction of the fluorescent wheel 27 is divided into a fluorescent area 27D. In this embodiment, the angle range of the fluorescent area is preferably greater than 270 degrees. Figure 3 In the example of FIG, the fluorescent area 27D is 360 degrees. The fluorescent area 27D is composed of a reflective coating layer, a fluorescent layer, and an anti-reflective coating layer stacked in this order from the bottom layer to the top layer.

[0101] The reflective coating has the property of reflecting light in the wavelength range of the fluorescent light Y generated by the fluorescent layer. If the disk member 27A is formed of a metal substrate with high reflectivity, the reflective coating can be omitted. The disk member 27A can also have the function of a reflective coating.

[0102] The phosphor layer can be made of, for example, a material in which a fluorescent material is dispersed in an organic or inorganic binder, a material that directly crystallizes the fluorescent material, or a rare earth phosphor such as Ce:YAG. The wavelength band of the fluorescent light Y in the phosphor layer can be, for example, yellow or green. This article uses fluorescent light Y in the yellow wavelength band as an example. The wavelength conversion unit is not limited to the phosphor wheel 27; phosphors or nonlinear optical crystals can also be used.

[0103] The anti-reflection coating has a property of preventing light from being reflected from the surface of the phosphor layer.

[0104] A reflective coating is laminated on the excitation light reflection region. The reflective coating has the property of reflecting light in the wavelength range of the excitation light P guided by the second optical system 26. If the disk member 27A is formed of a metal substrate with a high reflectivity, the reflective coating may be omitted. Alternatively, the disk member 27A may also function as a reflective coating.

[0105] As the drive motor 27C rotates the disk member 27A, the irradiation position of the excitation light P on the fluorescent wheel 27 moves over time. As a result, a portion of the excitation light P incident on the fluorescent wheel 27 is converted by the fluorescent region (wavelength conversion region) 27D into fluorescent light Y having a wavelength different from that of the excitation light P and then emitted.

[0106] like Figure 5 As shown, the majority of the light emitted from the light source unit 20 is yellow light with a wavelength range of 510 nm to 610 nm, which is highly visible. Other wavelengths also include the visible light range of 428 nm to 688 nm. Therefore, the light source unit 20 can provide image projection device 1 with light of excellent visibility.

[0107] The term "most" herein means that, when the radiant energy of the wavelength region corresponding to green to yellow light with a wavelength of 510 nm to 610 nm is set to A (W), the radiant energy of light with a wavelength less than 510 nm is set to B (W), and the radiant energy of light with a wavelength greater than 610 nm is set to C (W), A>B and A>C.

[0108] like Figure 2 As shown, excitation light P incident on fluorescent region 27D of fluorescent wheel 27 is converted into fluorescent light Y and then emitted. This fluorescent light Y is converted into substantially parallel light by second optical system 26, passes through quarter-wave plate 25, and then through polarization beam splitter 24, condenser lens 28, and enters light homogenization element 30.

[0109] Furthermore, if the excitation light source is cyan or the like and is not used as illumination light, that is, if it is used exclusively for excitation, the quarter-wave plate 25 is not necessarily required. Alternatively, the polarization beam splitter 24 may be a dichroic mirror that reflects the wavelength band of the excitation light and transmits the wavelength band of the fluorescence.

[0110] After emitting from the light homogenizing element 30, the fluorescent light Y is guided by the illumination optical system 40 to the image display element 50, forming an image. This image is then magnified and projected onto a screen 70 by the projection optical system 60, resulting in an image formed by the fluorescent light Y, namely, a yellow monochromatic image. While this embodiment uses a yellow phosphor as an example, a green monochromatic image can also be obtained if a green phosphor is used as the phosphor. A monochromatic image is an image represented by the shades (brightness and darkness) of monochromatic light with a certain spectral distribution. Shading can be achieved by controlling the brightness of each pixel in the image display element 50.

[0111] Here, as the simplest configuration for full-color display in a single-chip DMD system, calculations were performed using an image projection device that outputs minimally monochromatic R (red), G (green), and B (blue). The image projection device displays R, G, and B images in one frame, with each color allocated 120 degrees in three equal parts, with one frame representing one 360-degree cycle of the color wheel.

[0112] A single color can be obtained by dividing the time by 120 degrees for each color. However, considering that the diffusion of illumination light (equivalent to the spot size) across the color boundaries causes color mixing, this is called spoke time (hereinafter referred to as SP), and most signals in this area are cut off. The typical SP time is roughly 5 to 15 degrees. For example, considering a spot size of 10 degrees, in the case of an image projection device with equal angles for each color, each RGB color has 110 degrees, and there are 3 SP locations of 10 degrees, 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. At this time, the design is considered for a brightness of 5000 lumens.

[0113] RGB monochromatic output is distributed at wavelengths other than the dominant wavelength of the monochromatic color, making it difficult to calculate. However, to illustrate the effectiveness of this embodiment, a simplified approach has been employed, assuming, based on visibility characteristics, that for every 1 for G, each for B and R is 0.2. In other words, if we subtract 3 / 36 (1 / 12) of the SP output from each color of 5000 lumens, the remaining 4583 lumens is the sum of the RGB monochromatic outputs. This translates to 655 lumens for each of R and B, and 3273 lumens for G.

[0114] In this embodiment, since monochromatic light is projected, meaning a single wavelength range from green to yellow, the output light can allocate both the R and B time to the G region. The spectral luminous efficiency of B and R is approximately 0.2. Therefore, if the same radiant energy as that of R and B is output as G, the user will perceive it as five times brighter than R and B. In other words, the brightness is five times that of 655 lumens: 3274 lumens from R to G, and 3274 lumens from B to G. Adding the original 3274 lumens from G, the total brightness is 3274 lumens x 3 = 9822 lumens.

[0115] Since the SP portion is also projected entirely in G, adding at least 1 / 12 of 5000 lumens, or 417 lumens, yields a total of 10238 lumens, further improving brightness. In practice, there are practical limitations on how long to temporarily shut down (turn off) the DMD drive. However, it is understood that using a single color, particularly in the green to yellow wavelength range, significantly improves brightness. Thus, to achieve full-color output, a nearly two-fold brightness increase can be achieved simply by designing an image projection device designed for the required brightness to primarily project in the green wavelength range.

[0116] - Second example -

[0117] refer to Figures 6 to 10 The following describes the configuration of a second example light source unit included in the image projection apparatus according to the first embodiment of the present invention. The same names and symbols as those in the previously described embodiments represent identical or homogeneous components or configurations, and detailed descriptions thereof will be omitted as appropriate. This applies to the examples and embodiments described below.

[0118] Figure 6 It is a schematic diagram showing a configuration of a second example of the light source unit 20 included in the image projection apparatus 1 according to the first embodiment of the present invention. Figure 7 yes Figure 6 FIG. 2 is a schematic diagram showing an example of the structure of the fluorescent wheel 27 included in the light source unit 20 . Figure 8 This is a graph showing the proportion of the radiation intensity of yellow fluorescence in each wavelength range of light projected by the image projection device 1 according to the first embodiment of the present invention. The radiation intensity is between 510 nm and 610 nm. Figure 9 This is a graph showing the proportion of the radiation intensity of yellow fluorescence in each wavelength range of light projected by the image projection device 1 according to the first embodiment of the present invention. The radiation intensity is from 428 nm to 688 nm.

[0119] Figures 6 to 8 The second example shown is the same as Figures 2 to 5 The main difference of the first example shown is that a dichroic mirror 29 is provided which reflects blue light and transmits fluorescent light Y.

[0120] Here, consider irradiating a phosphor with a wavelength range from green to yellow with a blue light source, resulting in Y fluorescence output. 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 R, G, B, and Y, the ratio of the monochromatic colors (monochromatic brightness ratio) is R:G:B:Y = 0.08:0.3:0.03:0.3. The difference of 0.29 between the sum of R, G, B, and Y and 1 is the spoke time. As for the beam flux, when the brightness of the image projection device 1 is 5000 lumens, the brightness of R is 400 lumens, the brightness of G is 1500 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).

[0121] For the above, Figure 6 In the configuration shown, if the total of 0.1+0.16+0.26=0.52 of R, G, and B, excluding Y, is allocated to Y, then 0.52 / 0.17×1500=4588, which increases the brightness by 4588 lumens. That is, as the image projection device 1, 1500+4588=6088, which increases the brightness by 6088 lumens.

[0122] In the radiant energy ratio, 0.1 of R and 0.26 of B, totaling 0.36 or more, is the Y component. Even if the R and B values are doubled, the total is still 0.2 or 0.52, or at least 0.52 of the Y component. Furthermore, if 0.3 of the spoke time is also allocated to the Y radiant power, the result is 0.3 / 0.17 x 1500 = 2647 lumens, a further increase of 2647 lumens. This becomes 6088 + 2048 = 8735 lumens, a 1.75-fold increase, more than doubling the radiant energy ratio. If nearly all of the B is converted to the Y component, the ratio of the Y component to the B component increases infinitely.

[0123] In the case of the fluorescent light Y in this embodiment, as Figure 8 As shown, the energy E1 above 510nm and below 610nm is 77%, the energy E2 below 510nm is 4%, and the energy E3 above 610nm is 19%.

[0124] Since E1(77%)>E2(4%), E1(77%)>E3(19%), and E1(77%)>E2(4%)+E3(19%), it can be said that "most of the emitted light is green to yellow light with high visibility, ranging from 510nm to 610nm." Furthermore, since E1(77%)>2×E2(19%×2) and E1(77%)>2×E3(4%×2), it can be said that this is monochromatic light with a more ideal wavelength band.

[0125] like Figure 9 As shown, the radiant energy in the visible light wavelength band of 428nm to 688nm accounts for 98% of the total energy of fluorescent light Y. Therefore, it can be said that "the wavelength of light emitted from the light source unit is within the visible light wavelength band," and most of the radiant energy contributes to visual perception. In other words, fluorescent light Y is highly efficient for providing brighter, easier-to-see projected images.

[0126] -Projection optical system 60–

[0127] refer to Figure 10 and Figure 11 Next, a projection optical system 60 included in the image projection apparatus according to the first embodiment of the present invention will be described. Figure 10 It is a schematic diagram showing an example of the configuration of the projection optical system 60 included in the image projection apparatus 1 according to the first embodiment of the present invention. Figure 11 It is a schematic diagram showing an example of the configuration of a plurality of lenses 51 included in the image projection device 1 according to the first embodiment of the present invention.

[0128] Figure 10 The image display element 50 and the projection optical system 60 are displayed. Figure 11 Is the enlarged display Figure 10 The image display element 50 and a plurality of lenses 51 included in a portion of a refractive optical system 61 in a projection optical system 60 are shown. The image display element 50 includes an image forming section LV that forms the image to be projected. The image display element 50 illuminates the image formed in the image forming section LV with illumination light from the illumination optical system 40.

[0129] The following description assumes that the DMD is the image display element 50 and does not have a self-luminous function. However, the projection optical system 60 of this embodiment is not limited to this and can use a self-luminous method that can generate luminous images, or a light valve other than a DMD. The projection optical system 60 can also be a combination of lighting equipment, reflectors, dust-proof glass, etc., as long as it includes the image display element 50 and the projection optical system 60.

[0130] like Figure 10 As shown, a parallel plate CG is provided near the image forming portion LV of the image display element 50. The parallel plate CG is a plate that allows light to pass through and serves as the cover glass (sealing glass) of the image forming portion LV. The projection optical system 60 magnifies and projects the image formed by the image forming portion LV onto a screen 70 (see FIG. Figure 1 ), there are, in order from the image forming unit LV toward the screen 70, a refractive optical system 61 including a plurality of lenses 51 and a reflective optical system 64 including a reflective surface having optical power. Figure 11 The plurality of lenses 51 shown have an aperture S. The light (including the upper ray 101 and the principal ray 102) passing through the parallel flat plate CG from the image forming unit LV is Figure 10 The light path shown passes through a plurality of lenses 51 , is emitted from a refractive optical system 61 , passes through a reflective optical system 64 including a reflective mirror 62 and a curved reflective mirror 63 , and is projected onto a screen 70 .

[0131] For example, by designing the reflectivity characteristics of the reflector 62 and the curved mirror 63 to increase reflectivity across the wavelength band of the projected light, a brighter, more visible image projection device can be achieved. Furthermore, it is known that light that is not reflected, particularly in the curved reflector 63, generates heat and deforms the reflector, leading to deterioration in image quality. Improving reflectivity can also suppress this phenomenon, resulting in a more easily viewable projected image.

[0132] -Reflecting Mirror and Lens of Pattern Projection Device 1-

[0133] Figure 12 This is a graph showing the relationship between the reflectivity and wavelength of an example of a reflecting mirror included in the image projection device 1 according to the first embodiment of the present invention. Figure 13 Graph showing the relationship between the transmittance of the lens included in the image projection device 1 according to the first embodiment of the present invention and the wavelength.

[0134] Figure 12 The reflectivity of the reflector design results that can increase the reflectivity in the wavelength band of the light projected by the image projection device 1. Although it would be ideal to use a reflector with 100% reflectivity in all wavelength bands, this is very difficult. Therefore, the reflector must be designed or selected based on the wavelength range in which high reflectivity is required and the wavelength range that can be sacrificed. Figure 12 The reflectivity characteristics of Figure 5 In the spectral distribution of the fluorescence Y shown, the reflectivity near 510 nm and below 550 nm, where the intensity is high, is higher than the reflectivity at 450 nm or 650 nm. That is, the projection optical system 60 includes a reflector whose reflectivity for light with a wavelength of 510 nm and below 610 nm is higher than the reflectivity for light with a wavelength of 450 nm or 650 nm. The use of such a reflector can provide a brighter projection image with better visibility. In addition to the reflector included in the projection optical system 60, the reflector included in at least one of the projection optical system 60 and the light source unit 20 can have a reflectivity for light with a wavelength of 510 nm and below 610 nm that is higher than the reflectivity for light with a wavelength of 450 nm or 650 nm.

[0135] In order to achieve Figure 12To achieve the characteristics shown above, it is necessary to work on the reflective coating of the reflector. For example, one can evaporating aluminum on a resin substrate and then coating the surface with a reflection-enhancing film. Alternatively, silver can be used instead of aluminum, and other methods other than the above can be used. Figure 12 The reflecting mirror having the characteristics shown can be used for the projection optical system 60, the reflecting mirror in the light source unit 20, the micromirror in the image display element 50, and the like.

[0136] Here, the radiation energy of the light projected as the image displayed by the image display element 50 is A', and the radiation energy outside the green to yellow region of 510 nm to 610 nm is (B' + C'). In this case, the projection optical system 60 is equipped with Figure 12 In the case of a reflector having the characteristics shown in FIG. 1 , by adopting a configuration that satisfies A / (B+C) ≤ A' / (B'+C'), an image projection device 1 can be realized that can effectively project light in a wavelength band of 510 nm to 610 nm with high visibility. A / (B+C) ≤ A' / (B'+C') indicates that, in the projection optical system 60 and the like, the loss of radiant energy in the region of 510 nm to 610 nm is less than that in other regions.

[0137] The transmission characteristics of the glass material used for the lens included in the image projection device 1 include, for example, Figure 13 Glass materials such as glass material S1 and glass material S2 shown in the figure. At a wavelength of 460 nm, the transmittance of glass material S1 is greater than that of glass material S2. Conversely, at wavelengths of 550 nm and 650 nm, the transmittance of glass material S2 is greater than that of glass material S1. In other words, the projection optical system 60 includes a lens whose transmittance for light with a wavelength of 510 nm to 610 nm is greater than its transmittance for light with a wavelength of 450 nm. For example, glass material S2 having high transmittance for 550 nm light, which has high visibility, is a suitable glass material for the projection optical system 60. By using a lens formed from such glass material S2, a bright image projection device with excellent visibility can be realized. In addition to the lenses included in the projection optical system 60, the lenses included in at least one of the projection optical system 60 and the light source unit 20 may also have a transmittance for light with a wavelength of 510 nm to 610 nm that is higher than its transmittance for light with a wavelength of 450 nm or 650 nm.

[0138] [Second embodiment]

[0139] Reference below Figure 14 and Figure 15 , an image projection device according to a second embodiment of the present invention will be described. Figure 14 It is a schematic diagram showing an example of the configuration of the light source unit 20 included in the image projection apparatus according to the second embodiment of the present invention. Figure 15 FIG. 1 is a schematic diagram showing an example of the configuration of a stationary fluorescent unit 261 included in the image projection apparatus according to the second embodiment of the present invention.

[0140] like Figure 14 As shown, the image projection device of this embodiment is different from the image projection device of the first embodiment of the present invention in that it has a stationary fluorescent body unit 261 that is not driven to rotate, a first cooler 212 for cooling the excitation light source 21 of the light source unit 20, and a second cooler 262 for cooling the stationary fluorescent body unit 261.

[0141] Figure 15 2 shows the stationary fluorescent unit 261 viewed in a direction perpendicular to the incident direction of the blue light. Figure 15 As shown, stationary fluorescent unit 261 is composed of a fluorescent body 261b, which serves as a wavelength conversion component, stacked on a reflective member 261a, which reflects excitation light. For example, when viewed in the direction of incidence of blue light, reflective member 261a and fluorescent body 261b have a generally rectangular outer edge shape. Fluorescent body 261b is applied to reflective member 261a.

[0142] The stationary phosphor unit 261 corresponds to the wavelength conversion unit. Light emitted by the excitation light source enters the stationary phosphor unit 261, which then emits light having a different wavelength than the excitation light source. When blue light enters the stationary phosphor unit 261, it acts as excitation light for the phosphor 261b, causing the wavelength to be converted by the phosphor 261b. This results in, for example, fluorescent light Y having a yellow wavelength band with a luminous intensity center around 550 nm. Simultaneously, the fluorescent light undergoes Lambertian reflection through the interaction between the phosphor 261b and the reflective member 261a.

[0143] A portion of the blue light entering the stationary fluorescent unit 261 does not function as excitation light and is reflected by the reflective member 261a. Therefore, when the blue light enters the stationary fluorescent unit 261, it is emitted simultaneously with fluorescent light Y. The fluorescent light Y emitted from the stationary fluorescent unit 261 corresponds to "light satisfying A>B and A>C, where the radiant energy of light with a wavelength between 510 nm and 610 nm is A, the radiant energy of light with a wavelength less than 510 nm is B, and the radiant energy of light with a wavelength greater than 610 nm is C."

[0144] The stationary fluorescent body unit 261 does not rotate like the fluorescent body wheel 27 in the first embodiment. A second cooler 262 can be connected to the surface of the reflective member 261a opposite to the surface on which the fluorescent body 261b is laminated. By connecting the second cooler 262, the heat generation of the fluorescent body 261b can be suppressed, and high wavelength conversion efficiency can be expected, thereby providing a brighter and more easily viewed image projection device.

[0145] Figure 14 The light source unit 20 shown is a structure in which a plurality of excitation light sources 21 are housed and encapsulated in a light source housing 211. For example, by disposing a first cooler 212 on the opposite side of the excitation light emitting surface of the light source unit 20, the heat generation of the excitation light source 21 can be suppressed. The first cooler 212 can be made of a metal component or a carbon component with good thermal conductivity. The excitation light source 21 has a temperature characteristic in which the lower the temperature, the higher the light emission. Therefore, cooling with such a first cooler 212 can improve the light emission efficiency. As a result, a brighter and easier-to-view image projection device 1 can be realized.

[0146] [Third embodiment]

[0147] refer to Figures 16 to 18 , an image projection device according to a third embodiment of the present invention will be described. Figure 16 FIG. 1 is a schematic diagram showing an example of the configuration of a light source unit 20 included in an image projection apparatus according to a third embodiment of the present invention. Figure 17 This is a spectral distribution diagram of light emitted from the light source unit 20 included in the image projection apparatus according to the third embodiment of the present invention.

[0148] The image projection apparatus of this embodiment is different from the image projection apparatus of the first embodiment in that the light source unit 20 emits green light G.

[0149] like Figure 16 As shown, the green light G emitted from each of the multiple excitation light sources 21 is adjusted to be approximately parallel light by the corresponding collimating lens 22, and then focused by the first lens 23A and enters the light homogenizing element 30. The behavior of the light after the exit of the light homogenizing element 30 is similar to Figure 1 The operation is the same as shown. After being emitted from the light homogenizing element 30, the green light G is guided by the illumination optical system 40 to the image display element 50. The image projection device of this embodiment magnifies the image displayed by the image display element 50 and projects it onto the screen 70 via the projection optical system 60, thereby displaying a green monochromatic image.

[0150] For example, the excitation light source 21 emitting green light G can be a light source emitting laser light with a wavelength of 525 nm, a light source emitting laser light with a wavelength of 532 nm, a light source emitting laser light with a wavelength of 518 nm, or a combination of these light sources. By combining green excitation light sources 21 having 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. In addition to light sources emitting green light G, any excitation light source 21 emitting light with a wavelength between 510 nm and 610 nm can achieve an image projection device with excellent visibility.

[0151] The excitation light source 21 of this embodiment is as follows Figure 17 As shown in the spectral distribution, green light G is emitted in a very narrow wavelength band. Since all the light energy of the green light G is contained within the region with high spectral luminous efficiency, 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 enables a brighter image projection device with better visibility.

[0152] Since A(100%)>B(0%), and A(100%)>C(0%), A(100%)>B(0%)+C(0%), it can be said that "when the radiation energy of light with a wavelength of 510nm or more and 610nm or less is set to A, the radiation energy of light with a wavelength less than 510nm is set to B, and the radiation energy of light with a wavelength greater than 610nm is set to C, it is light that satisfies A>B and A>C". Moreover, since A(100%)>2B(0%×2), and A(100%)>2×C(0%×2), it can be said that it is monochromatic light of a more ideal wavelength band. If the image projection device of this embodiment has Figure 14 With the first cooler 212 shown, the brightness will be further improved.

[0153] While the preferred embodiments have been described in detail above, the present invention is not limited to the above embodiments, and various modifications and substitutions of the above embodiments are permitted without departing from the scope of the claims.

[0154] For example, in an embodiment, the brightness of the original projection light can be increased. Figure 18 This is a schematic diagram of the color distribution per cycle of the DLP method. In the DLP method image projection device, each color is projected in a time-division manner, so the wavelength with high visibility is projected only for a part of the time in one cycle (one frame). Figure 18In the example, a quarter of a frame is projected. To project a bright image, it is ideal to emit light with a wavelength that is highly visible for 100% of the time in one cycle (one frame). By projecting a monochromatic image, the time for emitting light with a wavelength that is highly visible can be set to 100% of the time in one cycle (one frame).

[0155] All numbers, such as ordinal numbers and quantities, used in the description of the embodiments are provided for the purpose of illustrating the technical aspects of the present invention, and the present invention is not limited to the numbers shown as examples. The connections between the components are provided for the purpose of illustrating the technical aspects of the present invention, and the connections for achieving the functions of the present invention are not limited thereto.

[0156] Various examples of application of the image projection device according to the embodiment will be described below.

[0157] <Head-mounted display device>

[0158] Figure 19A is a simplified stereoscopic diagram of a wearable display device 600 as an example of a projection device. Figure 19B yes Figure 19A A schematic diagram of a portion of the wearable display device 600 is shown.

[0159] The illustrated wearable display device 600 is a head-mounted display that can be worn on a person's head, for example, a head-mounted display device having a shape similar to glasses or goggles. Figure 19A In the embodiment, the wearable display device 600 is composed of a set of front parts 600a and temples 600b respectively arranged approximately symmetrically on the left and right. The front part 600a can be composed of a light guide plate 610, for example, and the optical system and control device can be built into the temples 600b.

[0160] Figure 19B This is a partial example diagram of the structure of the wearable display device 600. Figure 19B The configuration for the left eye is illustrated, but the wearable display device 600 for the right eye also has the same structure.

[0161] The wearable display device 600 includes, for example, a control device 11, a light source unit 100 as a light source device of this embodiment, a light quantity adjustment unit 607, a movable device 13 having a reflecting surface 14, a light guide plate 610, and a half-reflecting mirror 620.

[0162] The light source unit 100 is a unit composed of a laser light source, a collimating lens, a dichroic mirror, etc., via an optical housing.

[0163] Light from the light source unit 100 is adjusted in intensity by the light intensity adjustment unit 607 before entering the movable device 13. The movable device 13 moves the reflective surface 14 in the X and Y directions in response to a signal from the control device 11, thereby two-dimensionally scanning the light from the light source unit 100. The drive control of the movable device 13 is synchronized with the emission timing of the laser light source provided in the light source unit 100, for example.

[0164] 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 the scanning light to the half mirror 620. The light guide plate 610 is formed of a resin or the like that is transmissive to the wavelength of the scanning light.

[0165] The half-mirror 620 reflects the light from the light guide plate 610 to one side of the back side of the wearable display device 600, and emits it in the direction of the eye 630 of the wearer of the wearable display device 600. The half-mirror 620 has, for example, a free-form surface shape. The image formed by the scanned light is formed on the retina of the wearer's eye 630 by reflection from the half-mirror 620. Alternatively, the 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 body in the eyeball. The spatial distortion of the image is compensated by the reflection from the half-mirror 620. The wearer can see the image formed by the light scanned in the XY direction. By using the half-mirror 620, the wearer can overlap and observe the image formed by the light from the outside world and the image formed by the scanned light. It is also possible to eliminate the light from the outside world by setting a reflector instead of the half-mirror 620, so that only the image based on the scanned light can be observed.

[0166] Figure 19C Schematic diagram of another example of the structure of the wearable display device 600. As shown in (a), the control device 1000 of the wearable display device 600 is respectively provided in the left and right temples 600b, corresponding to the light source unit 100 and the movable device 13 respectively assembled in the left and right temples 600b.

[0167] The control device 1000 may also be as follows Figure 19C As shown in (b), it is set at the central position of the wearable display device 600 (the middle position of the left and right light guide plates 610, etc.), and the light source unit 100 and the movable device 13 assembled in the left and right temples 600b are controlled by a common control device 1000.

[0168] The wearable display device 600 can be as follows Figure 19D As shown, a helmet 650 is provided with a visor 640 including a light guide plate 610. In this case, the light source unit 100, the light quantity adjustment section 607, the movable device 13, the reflecting surface 14, and the control device 11 may also be built into the helmet 650 as shown.

[0169] Figure 19E 2 is a schematic diagram of the structure of another example of a wearable display device 600. The wearable display device 600 illustrated is a neckband display device that can be worn on a person's neck or shoulder.

[0170] exist Figure 19E In (a), a wearer 660 wearing a wearable display device 600 sits in front of a display 670 placed on a table 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 is equipped with a projector 680, which Figure 19E The image K of the input keyboard shown in (b) is projected onto the table D.

[0171] In addition to the projector 680, the wearable display device 600 may also be equipped with a camera. The camera detects the movement of the wearer's 660 finger on the image K of the input keyboard projected on the table D. The camera's detection result information is transmitted to, for example, the control device of the wearable display device 600. Based on the information received from the camera, the control device determines which key on the input keyboard the wearer 660 has pressed and displays information corresponding to the determination result on the display 670.

[0172] <Head-up display>

[0173] Figure 20A is a schematic diagram of an example of a car 400 equipped with a head-up display device 700 as an example of a projection device. Figure 20B 1 is a schematic diagram of an example of a head-up display device 700. The head-up display device 700 is a projection device that projects an image by, for example, light scanning.

[0174] like Figure 20A As shown, a head-up display device 700 is installed near the windshield 401 of a vehicle 400. Projection light L emitted from the head-up display device 700 is reflected by the windshield 401 and directed toward the driver 402 (observer), who is a user. This allows the driver 402 to visually perceive the image projected by the head-up display device 700 as a virtual image. Alternatively, a combiner may be provided on the inner wall of the windshield so that the projected light reflected by the combiner allows the user to perceive the virtual image.

[0175] like Figure 20BAs shown, the head-up display device 700 includes a light source unit 100, which is a light source device according to this embodiment. Light emitted from the light source unit 100 passes through a light intensity adjustment unit 707, for example, and is then deflected by a movable device 13 having a reflective surface 14. The deflected light then passes through a projection optical system consisting of a free-form mirror 709, an intermediate screen 710, and a projection mirror 711, and is projected onto a screen.

[0176] The head-up display device 700 projects an intermediate image displayed on the intermediate screen 710 onto the windshield 401 of the car 400 , allowing the driver 402 to visually recognize the intermediate image as a virtual image.

[0177] Light emitted from the light source unit 100 is adjusted in intensity by the light intensity adjustment unit 707 before being two-dimensionally scanned by the movable mechanism 13 having a reflective surface 14. Projection light L, two-dimensionally scanned by the movable mechanism 13, is reflected by the free-form surface reflector 709, where distortion is compensated, and then converged onto the intermediate screen 710, displaying an intermediate image. The intermediate screen 710 comprises a microlens array with microlenses arranged two-dimensionally, and amplifies the projection light L incident on the intermediate screen 710 on a microlens basis.

[0178] The movable device 13 reciprocates the reflecting surface 14 in two axial directions to two-dimensionally scan the projection light L incident on the reflecting surface 14. The driving control of the movable device 13 is synchronized with the emission timing of the laser light source provided in the light source unit 100, for example.

[0179] like Figure 20C As shown, the head-up display device 700 includes an imager 200 and a free-form surface mirror 709. The imager 200 includes a light source unit 100 as a light source device of this embodiment.

[0180] Light emitted from the light source unit 100 passes through, for example, an illumination system 201 before being irradiated onto an image forming unit 202. The image forming unit 202 includes a light modulator, such as a micromirror device and a liquid crystal panel. A control device 203 controls the operation of the light source included in the light source unit 100 and the operation of the light modulator included in the image forming unit 202. The image generated by the image forming unit 202 is projected through a projection lens 204, forming an intermediate image on an intermediate screen 205.

[0181] The head-up display device 700 reflects the image formed on the center screen 205 onto the windshield 401 of the car via the free-form surface mirror 709, allowing the driver 402 to visually recognize the virtual image I. A folding mirror may be disposed between the free-form surface mirror 709 and the windshield 401 as required for the layout.

[0182] The intermediate screen 205 is formed by, for example, a two-dimensional array of microlenses. In this embodiment, the microlens array is used to control viewing angle characteristics, improve viewing angle characteristics of the image projected onto the intermediate screen 205, and produce a brighter virtual image.

[0183] Projection devices are not limited to the projectors, wearable display devices, and head-up display devices described above. They are also not limited to being mounted on vehicles or the human body; they can also be mounted on, for example, railway vehicles, aircraft, and ships. Projection devices can also be mounted on mobile objects such as robots, drones, and unmanned aircraft that can move autonomously or remotely, or on non-mobile objects such as working robots that operate manipulators and other driven objects without leaving the site.

[0184] The present invention has the following aspects, for example.

[0185] <1> An image projection device, comprising:

[0186] light source unit;

[0187] an image display element for displaying an image after modulating the light emitted from the light source unit; and

[0188] a projection optical system for projecting the image displayed by the image display element,

[0189] When the radiation energy of light with a wavelength of 510 nm to 610 nm is set to A, the radiation energy of light with a wavelength less than 510 nm is set to B, and the radiation energy of light with a wavelength greater than 610 nm is set to C, the light source unit emits light satisfying A>B and A>C, and the image projected by the projection optical system is also formed by light satisfying A>B and A>C.

[0190] <2> according to <1> The image projection device is characterized in that the light source unit emits light that satisfies A>(B+C).

[0191] <3> according to <1> or <2> The image projection device, wherein the light source unit emits at least one light satisfying A≥2B and A≥2C.

[0192] <4> according to <1> to <3> The image projection device according to any one of the preceding claims, wherein the wavelength of the light emitted from the light source unit is within a wavelength band of visible light.

[0193] <5> according to <1> to <4> The image projection device according to any one of the preceding claims, wherein:

[0194] At least one of the projection optical system and the light source unit includes a reflecting mirror,

[0195] The reflectivity of the reflector to light with a wavelength of 510 nm to 610 nm is greater than the reflectivity of the reflector to light with a wavelength of 450 nm or 650 nm.

[0196] <6> according to <1> to <5> The image projection device according to any one of the preceding claims, wherein:

[0197] At least one of the projection optical system and the light source unit includes a lens,

[0198] The transmittance of the lens to light with a wavelength of 510 nm to 610 nm is greater than the transmittance of the lens to light with a wavelength of 450 nm.

[0199] <7> according to <1> to <6> The image projection device according to any one of the preceding claims, wherein the light source unit comprises a solid light source.

[0200] <8> according to <1> to <7> The image projection device according to any one of the preceding claims, wherein the light source unit includes an excitation light source and a wavelength conversion unit that emits light having a wavelength different from that of the light emitted from the excitation light source upon receiving light emitted from the excitation light source.

[0201] <9> according to <8> The image projection device comprises a first cooler for cooling the excitation light source.

[0202] <10> according to <8> The image projection device, wherein:

[0203] having a second cooler for cooling the wavelength conversion unit,

[0204] The wavelength conversion unit is a stationary phosphor unit that is not rotationally driven.

Claims

1. An image projection device, wherein: have: light source unit; an image display element for displaying an image after modulating the light emitted from the light source unit; and a projection optical system for projecting the image displayed by the image display element, When the radiation energy of light with a wavelength of 510 nm to 610 nm is set to A, the radiation energy of light with a wavelength less than 510 nm is set to B, and the radiation energy of light with a wavelength greater than 610 nm is set to C, the light source unit emits light satisfying A>B and A>C, and the image projected by the projection optical system is also formed by light satisfying A>B and A>C.

2. The image projection device according to claim 1, wherein The light source unit emits light satisfying A>(B+C).

3. The image projection device according to claim 1, wherein The light source unit emits at least one light satisfying A≥2B and A≥2C.

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

5. The image projection device according to claim 1, wherein At least one of the projection optical system and the light source unit includes a reflecting mirror, The reflectivity of the reflector to light with a wavelength of 510 nm to 610 nm is greater than the reflectivity of the reflector to light with a wavelength of 450 nm or 650 nm.

6. The image projection device according to claim 1, wherein: At least one of the projection optical system and the light source unit includes a lens, The transmittance of the lens to light with a wavelength of 510 nm to 610 nm is greater than the transmittance of the lens to light with a wavelength of 450 nm.

7. The image projection device according to claim 1, wherein: The light source unit includes a solid light source.

8. The image projection device according to claim 1, wherein: The light source unit includes an excitation light source and a wavelength conversion unit. The wavelength conversion unit emits light having a wavelength different from the wavelength of the light emitted from the excitation light source after light emitted from the excitation light source is incident thereon. 9 . The image projection apparatus according to claim 8 , further comprising a first cooler for cooling the excitation light source.

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

Images