JP2021182080A - Light source optical system, light source device and image projection device - Google Patents

Abstract

To provide a light source optical system, a light source device and an image projection device excellent in the utilization efficiency of light.SOLUTION: A light source optical system used with a plurality of excitation light sources emitting the first color light comprises: a wavelength conversion unit on which the first color light emitted from the plurality of excitation light sources is incident and which emits the second color light having a different wavelength from the first color light; and a first optical system and a second optical system with positive power which are provided in order on an optical path between the plurality of excitation light sources and the wavelength conversion unit. The light condensing point of each light flux emitted from the plurality of excitation light sources is formed between the first optical system and the second optical system.SELECTED DRAWING: Figure 6

Description

The present invention relates to a light source optical system, a light source device, and an image projection device.

Today, projectors (image projection devices) that magnify and project various images are widely used. The projector collects the light emitted from the light source on a spatial light modulation element such as a digital micromirror device (DMD) or a liquid crystal display element, and emits light from the spatial light modulation element modulated by the video signal on the screen. Is to be displayed as a color image.

Conventionally, a high-brightness ultra-high pressure mercury lamp or the like has been mainly used for a projector, but since the life is short, it is necessary to perform frequent maintenance. Therefore, in recent years, projectors using lasers, LEDs, or the like instead of ultra-high pressure mercury lamps are increasing. This is because lasers and LEDs have a longer life than ultra-high pressure mercury lamps, and their monochromaticity has good color reproducibility.

In a projector, an image is formed by irradiating an image display element such as a DMD with, for example, three colors of red, green, and blue, which are the three primary colors. Although it is possible to generate all of these three colors with a laser light source, it is not preferable because the luminous efficiency of the green laser and the red laser is lower than that of the blue laser. Therefore, a method of irradiating a phosphor with a blue laser as excitation light to generate red light and green light from the fluorescent light wavelength-converted by the phosphor is used. Patent Documents 1 and 2 disclose a light source optical system using (combining) such a laser light source and a phosphor.

Patent Document 1 describes an illumination optical system having an excitation light source, a phosphor unit, and a diffuser plate located on an optical path between the excitation light source and the phosphor unit to uniformly approach the intensity distribution of the excitation light. It has been disclosed. Patent Document 2 discloses a light source device having a plurality of light sources, a wavelength conversion element, and a plurality of mirror arrays and lens arrays located on an optical path between the plurality of light sources and the wavelength conversion element.

Japanese Patent No. 6090875 JP-A-2017-194523

In projectors, there is a growing demand for higher light utilization efficiency in order to realize brighter projectors. The efficiency of light conversion by the phosphor varies depending on the energy density of the excitation light incident on the phosphor, and when the energy density of the incident excitation light is high, the efficiency rises and the number of excitable electrons in the phosphor decreases. Decreases. Therefore, it is conceivable to improve the efficiency of light utilization by making the energy density uniform and increasing the spot size.

On the other hand, if the spot size of the excitation light on the phosphor is increased in order to suppress the energy density of the excitation light in the phosphor, the light beam eclipse in the subsequent (subsequent) optical system becomes large, so that the light in the entire projector is increased. Utilization efficiency decreases. That is, in order to improve the efficiency of light utilization in the projector, it is important to make the energy density uniform and obtain the optimum spot size.

In Patent Document 1 described above, by providing a diffuser plate between the excitation light source and the phosphor unit, the intensity of the excitation light incident on the phosphor unit is lowered, so that the light utilization efficiency of the entire projector is lowered. It ends up. In Patent Document 2 described above, not only the mirror array and the lens array lead to the increase in size, complexity and cost of the apparatus, but also the efficiency of the excitation light incident on the phosphor unit due to the absorption of the mirror array and the lens array and the like. Will decrease.

The present invention has been completed based on the above awareness of problems, and an object of the present invention is to provide a light source optical system, a light source device, and an image projection device having excellent light utilization efficiency.

The light source optical system of the present embodiment is a light source optical system used as a plurality of excitation light sources that emit first color light, and the first color light emitted from the plurality of excitation light sources is incident on the first color light. A wavelength conversion unit that emits a second color light having a wavelength different from that of the first color light, a first optical system provided in order on the optical path between the plurality of excitation light sources and the wavelength conversion unit, and positive power. It has a second optical system, and a focusing point of each light beam emitted from the plurality of excitation light sources is formed between the first optical system and the second optical system. It is characterized by.

According to the present invention, it is possible to provide a light source optical system, a light source device, and an image projection device having excellent light utilization efficiency.

It is a schematic block diagram which shows the projector by 1st Embodiment. It is a schematic block diagram which shows the light source apparatus by 1st Embodiment. It is a figure which shows the detailed structure of the fluorescent substance wheel by 1st Embodiment. It is a schematic block diagram which shows the color wheel. It is a figure which shows an example of the light ray passing through the 1st optical system and the 2nd optical system. It is a figure which shows the formation position of the condensing point of each light flux emitted from a plurality of laser light sources, and the formation position of the condensing point of the total luminous flux. It is a figure which shows an example of the spot in the phosphor wheel in the case of applying the light source optical system of this embodiment. It is a figure for demonstrating the conditional expression (1) which stipulated about a plurality of laser light sources and a plurality of collimator lenses. It is a schematic block diagram corresponding to FIG. 2 which shows the light source apparatus by 2nd Embodiment. It is a figure corresponding to FIG. 6 which shows the light source apparatus by 2nd Embodiment. 9 is an enlarged view showing the configuration of the optical element of FIGS. 9 and 10. It is a schematic block diagram corresponding to FIG. 2 which shows the light source apparatus by 3rd Embodiment. It is a schematic block diagram corresponding to FIG. 2 which shows the light source apparatus by 4th Embodiment. It is a figure which shows the detailed structure of the fluorescent substance wheel by 4th Embodiment. It is a schematic block diagram corresponding to FIG. 2 which shows the light source apparatus by 5th Embodiment. It is a figure which shows the detailed structure of the fluorescent substance wheel by 5th Embodiment. It is a figure which shows an example of the light ray passing through the 1st optical system and the 2nd optical system of the light source apparatus by 6th Embodiment. It is a schematic block diagram corresponding to FIG. 2 which shows the light source apparatus by 6th Embodiment. It is a schematic block diagram corresponding to FIG. 2 which shows the light source apparatus by 7th Embodiment.

<< First Embodiment >>
FIG. 1 is a schematic configuration diagram showing a projector (image projection device) 1 according to the first embodiment.

The projector 1 includes a housing 10, a light source device 20, a light homogenizing element 30, an illumination optical system 40, an image forming element (image display element) 50, and a projection optical system 60.

The housing 10 houses the light source device 20, the light homogenizing element 30, the illumination optical system 40, the image forming element 50, and the projection optical system 60.

The light source device 20 emits light including wavelengths corresponding to each color of RGB, for example. The internal configuration of the light source device 20 will be described in detail later.

The light homogenizing element 30 is homogenized by mixing the light emitted from the light source device 20. As the light homogenizing element 30, for example, a light tunnel combining four mirrors, a rod integrator, a fly-eye lens, or the like is used.

The illumination optical system 40 illuminates the image forming element 50 substantially uniformly with the light homogenized by the light homogenizing element 30. The illumination optical system 40 has, for example, one or more lenses, one or more reflecting surfaces, and the like.

The image forming element 50 has, for example, a light bulb such as a digital micromirror device (DMD), a transmissive liquid crystal panel, and a reflective liquid crystal panel. The image forming element 50 forms an image by modulating the light illuminated by the illumination optical system 40 (light from the light source optical system of the light source device 20).

The projection optical system 60 magnifies and projects the image formed by the image forming element 50 onto the screen (projected surface) 70. The projection optical system 60 has, for example, one or more lenses.

FIG. 2 is a schematic configuration diagram showing a light source device 20 according to the first embodiment.

The light source device 20 includes a laser light source (excitation light source) 21, a collimator lens 22, a first optical system 23, a polarization beam splitter (polarization optical element) 24, and 1 /, which are arranged in order in the light propagation direction. It has a four-wave plate 25, a second optical system 26, a phosphor wheel (wave wave conversion unit, phosphor unit) 27, a light source lens 28, and a color wheel 29. For example, the "light source optical system" is configured by the components of the light source device 20 excluding the laser light source 21.

The laser light source 21 has a plurality of light sources (solid-state light sources). In FIG. 2, six light sources arranged in the vertical direction are drawn, but in reality, six light sources are arranged in four rows in the direction perpendicular to the paper surface (depth direction), and 6 × 4 = 24 light sources. Are arranged in a two-dimensional array. Hereinafter, a plurality of light sources arranged in a two-dimensional array may be referred to as "a plurality of laser light sources (excitation light sources) 21". The plurality of laser light sources 21 are, for example, the center wavelength of the emission intensity as the excitation light B (first color light) that excites the phosphor provided in the fluorescence region (wavelength conversion region) 27D (described later) of the phosphor wheel 27. Emits light in the blue band of 455 nm (blue laser light). The blue laser light emitted from the plurality of laser light sources 21 is linearly polarized light having a constant polarization state, and is arranged so as to be S-polarized light with respect to the incident surface of the polarization beam splitter 24. The blue laser light emitted from the plurality of laser light sources 21 is coherent light. The excitation light B emitted from the plurality of laser light sources 21 may be light having a wavelength capable of exciting the phosphor in the fluorescence region 27D of the phosphor wheel 27, and is not limited to light in the blue band. .. The number of the plurality of laser light sources 21 is not limited to 24, and may be 2-23 or 25 or more. The plurality of laser light sources 21 can be configured as, for example, a light source unit in which a plurality of light sources are arranged in an array on a substrate, but there is a degree of freedom in the specific embodiment thereof.

A plurality of collimator lenses 22 are arranged in a two-dimensional array corresponding to a plurality of laser light sources 21. Twenty-four collimator lenses 22 are provided corresponding to the 24 light sources of the laser light source 21. The plurality of collimator lenses 22 adjust each light flux (excitation light B) emitted from the plurality of laser light sources 21 so as to be parallel light or convergent light. The number of collimator lenses 22 may be increased or decreased as long as it corresponds to the number of light sources of the laser light source 21 and can be increased or decreased according to the increase or decrease in the number of light sources of the laser light source 21.

As in the second embodiment (FIGS. 9 and 10) described later, the light is emitted from the plurality of laser light sources 21 between the plurality of laser light sources 21 (plural collimator lenses 22) and the first optical system 23. An optical element 200 can be arranged so that each light source is incident on the first optical system 23 as parallel light or convergent light. On the other hand, in the first embodiment, the functions of the optical element 200 are combined (combined) with the plurality of collimator lenses 22.

The first optical system 23 has positive power as a whole, and has a positive lens 23A and a negative lens 23B in this order from the side of the laser light source 21 toward the side of the phosphor wheel 27. The first optical system 23 guides the excitation light B incident from the collimator lens 22 as parallel light or convergent light to the polarizing beam splitter 24 while converging. The first optical system 23 may have a negative power instead of a positive power.

The polarization beam splitter 24 is located on the optical path between the first optical system 23 and the second optical system 26. The polarized beam splitter 24 reflects S-polarized light (first polarized light component) in the wavelength band of the excitation light B derived from the first optical system 23, while the excitation light B derived from the first optical system 23. A coating is applied so as to transmit P-polarized light (second polarized light component) and fluorescent light (second colored light) from the phosphor wheel 27 in the wavelength band of. In the first embodiment, a flat plate-shaped polarizing beam splitter 24 is used, but a prism type polarizing beam splitter 24 can also be used. Further, in the first embodiment, the polarized beam splitter 24 reflects the S-polarized light in the wavelength band of the excitation light B and transmits the P-polarized light, but on the contrary, the P in the wavelength band of the excitation light B. Polarized light may be reflected and S-polarized light may be transmitted.

Further, the polarizing beam splitter 24 located on the optical path between the first optical system 23 and the second optical system 26 passes through the excitation light B (first color light) and emits fluorescent light (second color light). Or may have the property of reflecting the excitation light B (first color light) and transmitting the fluorescent light (second color light).

The 1/4 wave plate 25 is arranged in a state where the optical axis is tilted by 45 degrees with respect to the linearly polarized light of the excitation light B reflected by the polarization beam splitter 24. The 1/4 wave plate 25 converts the excitation light B reflected by the polarization beam splitter 24 from linearly polarized light to circularly polarized light.

The second optical system 26 has positive power as a whole, and has a positive lens 26A and a positive lens 26B in this order from the side of the laser light source 21 toward the side of the phosphor wheel 27. The second optical system 26 guides the excited light B, which is converted into circularly polarized light from the 1/4 wave plate 25 and incident, to the phosphor wheel 27 while converging. The lens on the incident side of the second optical system 26 (positive lens 26A) may have an aspherical surface or a free curved surface. By arranging an aspherical surface or a free curved surface near the focusing point of the light flux from each light source of the laser light source 21, it is easy to individually correct the light flux of each light source of the laser light source 21, and the spot shape on the phosphor is shaped. It becomes possible to do.

Excitation light B guided from the second optical system 26 is incident on the phosphor wheel 27. FIG. 3 is a diagram showing a detailed structure of the phosphor wheel 27. The phosphor wheel 27 has a disk member (board) 27A and a drive motor (drive member) 27C that rotationally drives the disk member 27A around the rotation shaft 27B. As the disk member 27A, for example, a transparent substrate or a metal substrate (aluminum substrate or the like) can be used, but the disk member 27A is not limited thereto.

The phosphor wheel 27 (disk member 27A) has a large portion in the circumferential direction (an angle range larger than 270 ° in the first embodiment) partitioned by the fluorescent region 27D, and a small portion in the circumferential direction (first embodiment). The angle range smaller than 90 °) is partitioned into the excitation light reflection region 27E.

The fluorescence region 27D is configured by laminating a reflection coat 27D1, a phosphor layer 27D2, and an antireflection coat (AR coat) 27D3 in order from the lower layer side to the upper layer side.

The reflection coat 27D1 has a property of reflecting light in the wavelength region of the fluorescent light (emitted light) by the phosphor layer 27D2. When the disk member 27A is made of a metal substrate having a high reflectance, the reflective coat 27D1 can be omitted (it is also possible to give the disk member 27A the function of the reflective coat 27D1).

As the phosphor layer 27D2, for example, one in which the phosphor material is dispersed in an organic / inorganic binder, one in which crystals of the phosphor material are directly formed, and a rare earth phosphor such as Ce: YAG type can be used. .. As the wavelength band of the fluorescent light (emitted light) by the phosphor layer 27D2, for example, a wavelength band of yellow, blue, green, and red can be used, but in the first embodiment, fluorescent light having a wavelength band of yellow (emission light). The case of using (emission light) will be described as an example. Further, although a phosphor is used as the wavelength conversion element in this embodiment, a phosphorescent body, a nonlinear optical crystal, or the like may be used.

The antireflection coat 27D3 has a property of preventing the reflection of light on the surface of the phosphor layer 27D2.

A reflection coat (reflection surface) 27E1 having a characteristic of reflecting light in the wavelength region of the excitation light B derived from the second optical system 26 is laminated on the excitation light reflection region 27E. When the disk member 27A is made of a metal substrate having a high reflectance, the reflective coat 27E1 can be omitted (it is also possible to give the disk member 27A the function of the reflective coat 27E1).

By rotationally driving the disk member 27A by the drive motor 27C, the irradiation position of the excitation light B on the phosphor wheel 27 moves with time. As a result, a part of the excitation light B (first color light) incident on the phosphor wheel 27 is fluorescent light Y (first color light) having a wavelength different from that of the excitation light B (first color light) in the fluorescence region (wavelength conversion region) 27D. The other portion of the excitation light B incident on the phosphor wheel 27 is reflected and emitted as the excitation light B in the excitation light reflection region 27E.

The number and range of the fluorescence region 27D and the excitation light reflection region 27E have a degree of freedom, and various design changes are possible. For example, each of the two fluorescence regions and the excitation light reflection region may be alternately arranged at intervals of 90 ° in the circumferential direction.

This will be described again with reference to FIG. The excitation light B reflected by the excitation light reflection region 27E of the phosphor wheel 27 becomes circularly polarized light in the opposite direction, passes through the second optical system 26 and the 1/4 wave plate 25 again, and is converted into P-polarized light. The excitation light B converted to P-polarized light passes through the polarization beam splitter 24 and is incident on the color wheel 29 through the condenser lens 28.

On the other hand, the excitation light B incident on the fluorescence region 27D of the phosphor wheel 27 is converted into the fluorescence light Y and emitted. The fluorescent light Y is made substantially parallel light by the second optical system 26, passes through the 1/4 wave plate 25, passes through the polarizing beam splitter 24, and is incident on the color wheel 29 through the condenser lens 28.

FIG. 4 is a schematic configuration diagram showing the color wheel 29. The color wheel 29 has a blue region B, a yellow region Y, a red region R, and a green region G partitioned in the circumferential direction. The blue region B corresponds to the excitation light reflection region 27E of the phosphor wheel 27, and the yellow region Y, the red region R, and the green region G are synchronized so as to correspond to the fluorescent region 27D of the phosphor wheel 27, respectively. By arranging a transmission diffuser plate (not shown) in the blue region B, the coherence of the laser light source 21 can be reduced, and the speckle on the screen 70 can be reduced. The yellow region Y transmits the yellow wavelength region emitted from the phosphor wheel 27 as it is. By using a dichroic mirror in each of the red region R and the green region G, light in an unnecessary wavelength region is reflected from the yellow wavelength to obtain high-purity color light. Each color created by time division by the color wheel 29 is guided from the light equalizing element 30 to the image forming element 50 through the illumination optical system 40 to form an image corresponding to each color, and is magnified and projected onto the screen 70 by the projection optical system 60. By doing so, a color image can be obtained. That is, the image forming element (image display element) 50 modulates the light from the light source optical system to form an image, and the projection optical system 60 displays the image formed by the image forming element 50 on the screen (projected surface) 70. Enlarge and project to.

In the first embodiment, as a component of the light source optical system, the first positive power is sequentially provided on the optical path between the plurality of laser light sources (excitation light sources) 21 and the phosphor wheel (wavelength conversion unit) 27. It has an optical system 23 and a second optical system 26 with positive power.

The S-polarized excitation light B passes through the first optical system 23, but the fluorescent light Y does not. The S-polarized excitation light B, the P-polarized excitation light B, and the fluorescent light Y pass through the second optical system 26. As described above, the first optical system 23 and the second optical system 26 are separated in that the former allows the fluorescent light Y to pass through and the latter does not allow the fluorescent light Y to pass through. Further, the first optical system 23 and the second optical system 26 are separated at the location of the maximum air spacing.

The lens data and aspherical surface data of the first optical system 23 and the second optical system 26 are shown below.

As shown in the above lens data and aspherical surface data, in the first optical system 23, the positive lens 23A has a biconvex shape, and the negative lens 23B has a biconcave shape. Further, in the second optical system 26, the positive lens 26A has a biconvex shape, and the normal lens 26B has a plano-convex shape convex toward the object side. Aspherical surfaces are formed on both sides of the positive lens 26A. The configuration of the second optical system 26 is not limited to this, and for example, an aspherical surface may be formed on only one surface of the positive lens 26A, or an aspherical surface may be formed on both sides or one surface of the positive lens 26B. Further, in the first optical system 23, additional lenses may be provided in the positive lens 23A and the negative lens 23B, and in the second optical system 26, additional lenses may be provided in the positive lens 26A and the positive lens 26B. It is also good. Although not shown, an aperture stop for adjusting the amount of excitation light B is provided at any position on the optical path of the light source optical system (for example, immediately before the positive lens 23A of the first optical system 23). It may be provided.

FIG. 5 is a diagram showing an example of light rays passing through the first optical system 23 and the second optical system 26. As shown in FIG. 5, in the first optical system 23, when a light ray parallel to the optical axis A of the first optical system 23 is incident, the light ray emitted from the first optical system 23 is on the optical axis A. It has optical characteristics such that it is incident on the second optical system 26 while approaching (condensing) at a predetermined angle.

Here, in the present embodiment, a blue laser beam (first color light) is guided to the phosphor wheel 27 in order to improve the light utilization efficiency in the projector 1 by making the energy density uniform and obtaining the optimum spot size. The characteristics of the optical system are specified by focusing on "condensing points F for each of a plurality of laser light sources (excitation light sources) 21 (positions)". Each condensing point F corresponds to an intermediate image formed by each of the plurality of laser light sources 21. In a normal (conventional) light source optical system, an intermediate image is not formed by each of a plurality of laser light sources (has no focusing point), and the light is simply focused in the vicinity of the phosphor. Further, in the present embodiment, by appropriately setting the incident light flux to the first optical system 23, the uniformity of the spot in the phosphor wheel 27 and the damage of the phosphor layer (wavelength conversion layer) are prevented.

FIG. 6 is a diagram showing the formation position of the focusing point F of each light flux emitted from the plurality of laser light sources 21 and the forming position of the focusing point Fall of the total luminous flux.

The condensing point F of each light flux emitted from the plurality of laser light sources 21 is formed between the first optical system 23 and the second optical system 26. As a result, the fluorescence spot size of the phosphor wheel 27 can be made appropriate and the energy density can be made uniform without using a homogenizing element such as a diffuser plate or a microlens array. The conversion efficiency can be improved, and the light utilization efficiency of the entire projector 1 can be improved. Further, by forming the condensing point F in a portion without the optical member, it is possible to prevent the optical member from being destroyed by the concentration of light energy and the refractive index distribution from being changed.

Further, the plurality of collimator lenses 22 have a function of an "optical element" in which each light flux incident from the plurality of laser light sources 21 is incident on the first optical system 23 as parallel light or convergent light. As a result, the spots on the phosphor wheel 27 can be made uniform and the wavelength conversion efficiency can be improved. As the "optical element", for example, a lens array, a diffractive optical element, a hologram, or the like can be used, but in FIG. 6, as a configuration example of the plurality of collimator lenses 22, the first is corresponding to a plurality of laser light sources 21. An example is a lens array 22Y provided with a plurality of positive lenses (positive lens groups) 22X protruding toward the optical system 23 of the above. As a result, the "optical element" can be configured with high efficiency and low cost.

In FIG. 6, the light rays emitted from the plurality of laser light sources 21 each form a light beam, and the light rays are incident on a plurality of positive lenses (positive lens group) 22X corresponding to the plurality of laser light sources 21, so that each light beam is parallel light. Alternatively, it becomes convergent light and is emitted from a plurality of positive lenses (positive lens group) 22X. The plurality of positive lenses (positive lens group) 22X are a plurality of collimator lenses 22 that collimate the light beam of the light source, and by moving the plurality of collimator lenses 22 in the optical axis direction, a plurality of positive lenses (positive lens group) are used. ) It is also possible to make the light beam emitted from 22X a parallel light or a convergent light.

Here, when each light flux to the first optical system 23 is divergent light, the spots on the phosphor wheel 27 are not uniformized, and an image corresponding to a plurality of laser light sources 21 is formed, which is very difficult. The spot diameter becomes small, the light collection density in the phosphor wheel 27 increases, the wavelength conversion efficiency decreases, and the wavelength conversion layer becomes burnt.

In this respect, in the present embodiment, the parallel light or the convergent light emitted from the plurality of positive lenses (positive lens group) 22X is further converged by the first optical system 23, and the first optical system 23 and the second optical system are further converged. A light collecting point F is formed between the systems 26, particularly in the vicinity of the transmission surface / reflection surface of the polarizing beam splitter 24. As a result, it is possible to improve the efficiency of light utilization in the projector 1 by making the energy density uniform and obtaining the optimum spot size, and to prevent the phosphor layer (wavelength conversion layer) from being destroyed by heat.

At least half (50% or more) of the focusing point F of each light flux emitted from the plurality of laser light sources 21 is located closer to the first optical system 23 than to the second optical system 26. Is preferable. As a result, the uniformity of the spot on the phosphor wheel 27 can be further improved. It should be noted that 70% or more, 80% or more, 90% or more, or 100% (all) of the light collection points F of each light flux emitted from the plurality of laser light sources 21 are higher than those of the second optical system 26. It may be located on the side closer to the optical system 23 of 1.

At least half (50% or more) of the light flux focusing points F emitted from the plurality of laser light sources 21 are the transmission surface of the first optical system 23 and the polarizing beam splitter (polarizing optical element) 24 (transmissive surface). It is preferably located between the reflective surfaces). As a result, the uniformity of the spot on the phosphor wheel 27 can be further improved. Further, it is possible to prevent the light energy from concentrating on the transmissive surface / reflective surface of the polarizing beam splitter 24 and prevent damage to the reflective coat or the like of the polarizing beam splitter 24. It should be noted that 70% or more, 80% or more, 90% or more or 100% (all) of the focusing points F of the light flux emitted from the plurality of laser light sources 21 are the first optical system 23 and the polarizing beam. It may be located between the splitters (polarizing optical elements) 24 (transmission surface / reflection surface).

At least half (50% or more) of the condensing point F of each light beam emitted from the plurality of laser light sources 21 is the first with reference to the polarizing beam splitter (polarizing optical element) 24 (transmission surface / reflection surface). It is preferably located closer to the first optical system 23 than to the second optical system 26. As a result, the uniformity of the spot on the phosphor wheel 27 can be further improved. Further, it is possible to prevent the light energy from concentrating on the transmissive surface / reflective surface of the polarizing beam splitter 24 and prevent damage to the reflective coat or the like of the polarizing beam splitter 24. The focusing point F of each light beam emitted from the plurality of laser light sources 21 is 70% or more, 80% or more, 90% or more, or 100% (all) of the polarizing beam splitter (polarizing optical element) 24. It may be located closer to the first optical system 23 than the second optical system 26 with reference to (transmission surface / reflection surface).

As shown in FIG. 6, the focusing point Fall of the total luminous flux emitted from the plurality of laser light sources 21 is a phosphor in the optical path rather than the polarizing beam splitter (polarizing optical element) 24 (transmission surface / reflection surface). It is located near the wheel 27. Here, the "total luminous flux emitted from the plurality of laser light sources 21" means a bundle including all the light rays emitted from the plurality of laser light sources 21 (all light sources). Further, the focusing point Fall of the total luminous flux emitted from the plurality of laser light sources 21 is located so as to overlap with at least a part of the second optical system 26 in the optical path. In the example of FIG. 6, the focusing point Fall of the total luminous flux emitted from the plurality of laser light sources 21 is located so as to overlap with the positive lens 26B of the second optical system 26. As a result, the spot on the phosphor wheel 27 can be blurred and made uniform, and a high-efficiency, compact, and low-cost light source optical system can be realized.

FIG. 7 is a diagram showing an example of a spot on the phosphor wheel 27 when the light source optical system of the present embodiment is applied. From FIG. 7, it can be understood that the spots on the phosphor wheel 27 are made uniform, and the efficiency of light utilization in the projector 1 can be improved.

As described above, the plurality of laser light sources 21 and the plurality of collimator lenses 22 are arranged in a two-dimensional array so as to correspond to each other. Here, as shown in FIG. 8, when the direction in which the divergence angle of the plurality of laser light sources 21 is maximized is defined as the X direction, the divergence angle in the X direction is θx, and the pitch of the plurality of laser light sources 21 in the X direction. Is Px, and when the distance between the plurality of laser light sources 21 and the plurality of collimator lenses 22 is L, it is preferable that the following conditional expression (1) is satisfied.
(1) 0.5 <Px / L · tanθx <2

By satisfying the conditional expression (1), the optimum setting can be made while suppressing the distance between the profiles of each emission point of the plurality of laser light sources 21, so that the overall profile becomes dense and the phosphor wheel 27 is reduced. Sometimes a uniform profile can be obtained and the fluorophore conversion efficiency can be improved.

When the upper limit of the conditional expression (1) is exceeded, the distance between the emission points of the plurality of laser light sources 21 and, by extension, the distance between the profiles of the emission points becomes large. Therefore, when it is desired to obtain a desired spot size in the phosphor wheel 27, the reduction ratio becomes too large, the image of each light emitting point becomes small, the focusing density in the phosphor wheel 27 becomes large, and the wavelength conversion efficiency becomes large. Will drop.

Below the lower limit of the conditional equation (1), it is easy to obtain a uniform profile with the phosphor wheel 27, but the light from each light emitting point is incident on the adjacent collimator lens 22, and a part of the light rays travels in an unintended direction. As a result, not only is it stray light, but the efficiency of the optical system is reduced.

<< Second Embodiment >>
The projector 1 according to the second embodiment will be described in detail with reference to FIGS. 9 to 11. The same reference numerals are given to the configurations common to those of the first embodiment, and duplicate description will be omitted.

In the first embodiment described above, the function of the "optical element" that causes each light beam emitted from the plurality of laser light sources 21 to be incident on the first optical system 23 as parallel light or convergent light is combined with the plurality of collimator lenses 22. I had it (I had it double). On the other hand, in the second embodiment, a plurality of collimator lenses 22 and an optical element 200 of a separate member are provided between the plurality of collimator lenses 22 and the first optical system 23.

The light rays emitted from the plurality of laser light sources 21 each form a light beam and are incident on the plurality of collimating lenses 22 corresponding to the plurality of laser light sources 21, so that each light beam becomes parallel light or divergent light and a plurality of collimators. It is emitted from the lens 22 and incident on the optical element 200. The optical element 200 is composed of a lens array 220 provided with a plurality of positive lenses (positive lens groups) 210 corresponding to the plurality of laser light sources 21 and projecting to the side of the first optical system 23 (see FIG. 11). ).

Here, the power of the plurality of positive lenses (positive lens group) 210 of the optical element 200 is weaker than the power of the positive lenses (positive lens group) of the plurality of collimating lenses 22. Therefore, each light flux that has passed through the optical element 200 becomes parallel light or convergent light, is emitted from the optical element 200, and is incident on the first optical system 23. Each light beam emitted from the optical element 200 is converged by the first optical system 23, and is split between the first optical system 23 and the second optical system 26 from the transmission surface / reflection surface of the polarization beam splitter 24. A condensing point F is formed in the foreground. Further, the focusing point Fall of the total luminous flux emitted from the optical element 200 is located on the side closer to the phosphor wheel 27 than the transmissing surface / reflecting surface of the polarizing beam splitter 24 in the optical path. Further, the focusing point Fall of the total luminous flux emitted from the optical element 200 is located in the optical path so as to overlap with at least a part of the second optical system 26 (here, the positive lens 26B).

<< Third Embodiment >>
The projector 1 according to the third embodiment will be described in detail with reference to FIG. The same reference numerals are given to the configurations common to those of the first embodiment, and duplicate description will be omitted.

The third embodiment differs from the first embodiment in the following points. That is, the excitation light B emitted from the laser light source 21 is P-polarized light, and the polarization beam splitter 24 transmits the P-polarized light excitation light B derived from the first optical system 23, while the 1/4 wavelength plate. It has the property of reflecting the excitation light B and the fluorescent light Y converted into S-polarized light from the 25, the second optical system 26, and the phosphor wheel 27.

<< Fourth Embodiment >>
The projector 1 according to the fourth embodiment will be described in detail with reference to FIGS. 13 and 14. The same reference numerals are given to the configurations common to those of the first embodiment, and duplicate description will be omitted.

In the fourth embodiment, in the first embodiment, the condenser lens 28 and the color wheel 29 are omitted, and the configurations of the phosphor wheel 27 are different.

FIG. 14 is a diagram showing a detailed structure of the phosphor wheel 27 according to the fourth embodiment. The phosphor wheel 27 of the fourth embodiment is not divided into a fluorescence region 27D and an excitation light reflection region 27E in the circumferential direction as in the first embodiment, and is not divided into a fluorescence region (wavelength conversion region) over the entire circumference in the circumferential direction. ) 27G is provided.

The fluorescence region 27G is configured by laminating a first reflection coat 27G1, a phosphor layer 27G2, and a second reflection coat 27G3 in order from the lower layer side to the upper layer side.

The first reflection coat 27G1 has a characteristic of reflecting the light in the wavelength region of the excitation light B derived from the second optical system 26 and the light in the wavelength region of the fluorescent light (emission light) by the phosphor layer 27G2. Have.

As the phosphor layer 27G2, for example, a phosphor material dispersed in an organic / inorganic binder, a fluorophore material crystal directly formed, or a rare earth phosphor such as Ce: YAG can be used. By setting the wavelength band of the fluorescent light (emitted light) by the phosphor layer 27G2 to yellow, for example, white light can be obtained by combining with the blue color of the excitation light.

The second reflection coat 27G3 reflects a part of the excitation light B derived from the second optical system 26, while the other part of the excitation light B derived from the second optical system 26 and the phosphor layer 27G2. It has the property of transmitting fluorescent light (emitted light).

The excitation light B reflected by the second reflection coat 27G3 of the phosphor wheel 27 becomes circularly polarized light in the opposite direction, passes through the second optical system 26 and the 1/4 wave plate 25 again, and is converted into P-polarized light. NS. The excitation light B converted to P-polarized light passes through the polarization beam splitter 24 and is incident on the light homogenizing element 30. On the other hand, the excitation light B transmitted through the second reflection coat 27G3 of the phosphor wheel 27 is converted into fluorescent light Y by the phosphor layer 27G2 and reflected by the first reflection coat 27G1. The fluorescent light Y is made into substantially parallel light by the second optical system 26, passes through the 1/4 wave plate 25, passes through the polarizing beam splitter 24, and is incident on the light homogenizing element 30.

<< Fifth Embodiment >>
The projector 1 according to the fifth embodiment will be described in detail with reference to FIGS. 15 and 16. The same reference numerals are given to the configurations common to those of the first embodiment, and duplicate description will be omitted.

In the fifth embodiment, the polarization beam splitter 24, the quarter wave plate 25, the condenser lens 28, and the color wheel 29 are omitted in the first embodiment. Further, a dichroic mirror 90 is provided at a position where the polarization beam splitter 24 was located. Further, a blue light source 91, a collimator lens 92, and a third optical system 93 are provided on the side opposite to the first optical system 23 sandwiching the dichroic mirror 90.

The blue light source 91 has a plurality of light sources (solid light sources). Each light source of the blue light source 91 emits light in a blue wavelength region (blue laser light) different from the excitation light B. A plurality of collimator lenses 92 are provided corresponding to a plurality of light sources of the blue light source 91. In FIG. 15, three blue light sources 91 and a collimator lens 92 arranged in the vertical direction are drawn, but the set of the blue light source 91 and the collimator lens 92 is arranged in a plurality of rows in the direction perpendicular to the paper surface (depth direction). It may be (may be two-dimensionally arranged). The collimator lens 92 adjusts the blue laser light emitted by each light source of the blue light source 91 so as to be parallel light. The number of the blue light source 91 and the collimator lens 92 can be increased or decreased as appropriate. The third optical system 93 has a biconvex positive lens 93A and a biconcave negative lens 93B, and passes through a blue laser beam from a blue light source 91 and a collimator lens 92 to form a dichroic mirror 90. Guide. As the blue light source 91, for example, a light emitting diode may be used in addition to the laser light source.

The dichroic mirror 90 reflects the excitation light B derived from the first optical system 23 toward the second optical system 26, and the blue laser light guided from the third optical system 93 is reflected by the optical homogenizing element 30. Reflects towards. Further, the dichroic mirror 90 transmits the fluorescent light from the phosphor wheel 27 toward the light homogenizing element 30. The excitation light B reflected by the dichroic mirror 90 passes through the second optical system 26 and is incident on the phosphor wheel 27.

FIG. 16 is a diagram showing a detailed structure of the phosphor wheel 27 according to the fifth embodiment. The phosphor wheel 27 of the fifth embodiment is not divided into a fluorescence region 27D and an excitation light reflection region 27E in the circumferential direction as in the first embodiment, and is not divided into a fluorescence region (wavelength conversion region) over the entire circumference in the circumferential direction. ) 27H is provided.

The fluorescence region 27H is configured by laminating a reflection coat 27H1, a phosphor layer 27H2, and an antireflection coat (AR coat) 27H3 in order from the lower layer side to the upper layer side.

The reflection coat 27H1 has a property of reflecting light in the wavelength region of the fluorescent light (emitted light) by the phosphor layer 27H2. When the disk member 27A is made of a metal substrate having a high reflectance, the reflective coat 27H1 can be omitted (it is also possible to give the disk member 27A the function of the reflective coat 27H1).

As the phosphor layer 27H2, for example, one in which the phosphor material is dispersed in an organic / inorganic binder, one in which crystals of the phosphor material are directly formed, and a rare earth phosphor such as Ce: YAG type can be used. .. The wavelength band of the fluorescent light (emitted light) by the phosphor layer 27H2 is, for example, white light obtained by combining with the blue laser light emitted from each light source of the blue light source 91.

The antireflection coat 27H3 has a property of preventing the reflection of light in the phosphor layer 27H2.

The excitation light B incident on the fluorescence region 27H of the phosphor wheel 27 is converted into the fluorescence light Y and emitted. The fluorescent light Y is made substantially parallel light by the second optical system 26, passes through the dichroic mirror 90, and is incident on the light homogenizing element 30. On the other hand, the blue laser light emitted from each light source of the color light source 91 is converted into parallel light by the collimator lens 92, passes through the third optical system 93, and is reflected by the dichroic mirror 90, whereby the light homogenizing element 30 is used. Incident to.

<< 6th Embodiment >>
The projector 1 according to the sixth embodiment will be described in detail with reference to FIGS. 17 and 18. The same reference numerals are given to the configurations common to those of the first embodiment, and duplicate description will be omitted.

In the sixth embodiment, in the first embodiment, the 1/4 wave plate 25 between the polarizing beam splitter 24 and the second optical system 26 is omitted, and the dichroic mirror (color) is located at the position where the polarizing beam splitter 24 is located. Separation optical element) 100 is provided. The dichroic mirror 100 located on the optical path between the first optical system 23 and the second optical system 26 transmits the excitation light B (first color light) and reflects the fluorescent light (second color light). Or, it can have a property of reflecting the excitation light B (first color light) and transmitting the fluorescent light (second color light).

At least half (50% or more) of the focusing point F of each luminous flux emitted from the plurality of laser light sources 21 is located between the first optical system 23 and the dichroic mirror (color separation optical element) 100. Is preferable.

At least half (50% or more) of the condensing points F of each light beam emitted from the plurality of laser light sources 21 are higher than those of the second optical system 26 with reference to the dichroic mirror (color separation optical element) 100. It is preferably located on the side closer to the optical system 23 of 1.

It is preferable that the focusing point Fall of the total luminous flux emitted from the plurality of laser light sources 21 is located closer to the phosphor wheel 27 than the dichroic mirror (color separation optical element) 100 in the optical path.

Further, the optical axis X of the first optical system 23 and the optical axis Y of the second optical system 26 are eccentric in a direction perpendicular to the optical axis. As a result, the excitation light B emitted from the first optical system 23 is incident on one side of the second optical system 26 (the lower side of the optical axis Y in FIG. 17). Here, in the sixth embodiment, the behavior of light when the optical axis X of the first optical system 23 and the optical axis Y of the second optical system 26 are aligned is the same as that of the first embodiment.

In the first embodiment, the polarization direction (S-polarized light, P-polarized light) is defined, but in the sixth embodiment, the polarized light may be arranged in any direction. The light emitted from the laser light source 21 is converted into a parallel light beam by the collimator lens 22, then passes through the first optical system 23, is reflected by the excitation light B, and is reflected by the dichroic mirror 100 that transmits the fluorescent light Y. It is guided to the optical system 26 of 2. By arranging the first optical system 23 so as to be eccentric with respect to the second optical system 26, the excitation light B is incident from one side of the second optical system 26 and is oblique to the phosphor wheel 27. Is incident on. The excitation light B incident on the fluorescence region 27D of the fluorescence wheel 27 is converted into fluorescence light Y and guided to the light homogenizing element 30 through the same optical path as in the first embodiment.

On the other hand, since the excitation light B incident on the excitation light reflection region 27E of the phosphor wheel 27 is specularly reflected, the side incident on the second optical system 26 (left side in FIG. 18) is as shown in FIG. It is emitted from the second optical system 26 through the opposite side (right side in FIG. 18). The excitation light B emitted from the second optical system 26 does not pass through the dichroic mirror 100, but is incident on the condenser lens 28 and is guided to the color wheel 29 and the light homogenizing element 30.

In the sixth embodiment, the excitation light B reflected by the excitation light reflection region 27E of the phosphor wheel 27 does not pass through the dichroic mirror 100, but the dichroic mirror 100 is enlarged and the coat on half of the surface is excited. It is also possible to use a dichroic mirror 100 having a characteristic of reflecting light B and transmitting fluorescent light Y, and having a characteristic of transmitting the excitation light B and the fluorescent light Y for the other half.

<< 7th Embodiment >>
The projector 1 according to the seventh embodiment will be described in detail with reference to FIG. The same reference numerals are given to the configurations common to those of the first embodiment, and duplicate description will be omitted.

In the seventh embodiment, in the sixth embodiment, in addition to the set of the laser light source 21 and the collimator lens 22, the set of the laser light source 21X and the collimator lens 22X located below the laser light source 21 is included. The set of the laser light source 21 and the collimator lens 22 and the set of the laser light source 21X and the collimator lens 22X both emit P-polarized excitation light B.

The light source device 20 synthesizes the excitation light B emitted by the set of the laser light source 21 and the collimator lens 22 and the set of the laser light source 21X and the collimator lens 22X, and emits the combined optical system 110 to the first optical system 23. have.

The synthetic optical system 110 includes a 1/2 wave plate 112, a reflection mirror 114, and a polarizing beam splitter 116.

The 1/2 wave plate 112 converts the excitation light B emitted by the set of the laser light source 21X and the collimator lens 22X from P-polarized light to S-polarized light.

The reflection mirror 114 reflects the excitation light B converted into S-polarized light by the 1/2 wave plate 112 toward the polarizing beam splitter 116.

The polarization beam splitter 116 has a property of reflecting S-polarized excitation light B while transmitting P-polarized excitation light B. The polarization beam splitter 116 transmits the P-polarized excitation light B emitted by the set of the laser light source 21 and the collimator lens 22 and guides the polarization beam splitter 116 to the first optical system 23. The polarization beam splitter 116 reflects the S-polarized excitation light B reflected by the reflection mirror 114 and guides it to the first optical system 23. In this way, the P-polarized light and the S-polarized light B are combined and incident on the first optical system 23.

The laser light source 21 and the laser light source 21X are each formed on independent substrates, and the distance at which the distance between any two light emitting points of the laser light source 21 is maximized is Smax1, and the laser light source 21X emits light. When the distance at which the distance between any two light source points is maximized is Smax2, the larger of Smax1 and Smax2 can be Smax. For example, when the same light source array is used as the laser light source 21 and the laser light source 21X, Smax1 = Smax2 = Smax is established.

Here, the case where the set of the laser light source 21 and the collimator lens 22 and the set of the laser light source 21X and the collimator lens 22X both emit P-polarized excitation light B has been described as an example. The excitation light B may be emitted. Further, although the case where the excitation light B is synthesized by using the polarizing beam splitter 116 has been described as an example, it is also possible to synthesize the excitation light B by using a comb tooth mirror or the like.

As described above, in the light source optical system, the light source device, and the projector (image projection device) of the present embodiment, the condensing point of each light source emitted from the plurality of laser light sources (excitation light sources) 21 is the first optical. It is formed between the system 23 and the second optical system 26. As a result, the efficiency of light utilization can be improved by making the energy density uniform and obtaining the optimum spot size. Further, since it is not necessary to use a homogenizing element such as a diffuser plate or a microlens array, it is possible to reduce the size, simplification and cost.

In addition, although the preferred embodiment of the present invention is shown in each of the above-described embodiments, the present invention is not limited to the contents thereof. In particular, the specific shapes and numerical values of each part exemplified in each embodiment are merely examples of the embodiment of the present invention, and the technical scope of the present invention may be construed in a limited manner by these. It shouldn't be. As described above, the present invention is not limited to the contents described in the present embodiment, and can be appropriately modified without departing from the gist thereof.

1 Projector (image projection device)
10 Housing 20 Light source device 21 21X Laser light source (excitation light source)
22 22X Collimator lens (light source optical system)
22X Multiple positive lenses (positive lens group)
22Y lens array 23 first optical system (light source optical system)
23A Positive lens 23B Negative lens 24 Polarized beam splitter (light source optical system, polarized optical element)
25 1/4 wave plate (light source optical system)
26 Second optical system (light source optical system)
26A Positive lens 26B Positive lens 27 Fluorescent wheel (light source optical system, wavelength conversion unit, phosphor unit)
27A disk member (board)
27B rotary shaft 27C drive motor (drive member)
27D fluorescence region (wavelength conversion region)
27D1 Reflective coat 27D2 Fluorescent layer 27D3 Anti-reflective coat (AR coat)
27E Excited light reflection region 27E1 Reflection coat (reflection surface)
27G fluorescence region (wavelength conversion region)
27G1 First reflection coat 27G2 Fluorescent material layer 27G3 Second reflection coat 27H Fluorescent region (wavelength conversion region)
27H1 Reflective coat 27H2 Fluorescent layer 27H3 Anti-reflective coat (AR coat)
28 Condensing lens (light source optical system)
29 color wheel (light source optical system)
30 Optical homogenization element 40 Illumination optical system 50 Image forming element (image display element)
60 Projection optical system 70 Screen (projected surface)
90 Dichroic mirror (light source optical system)
91 Blue light source (light source optical system)
92 Collimator lens (light source optical system)
93 Third optical system (light source optical system)
100 Dichroic mirror (color separation optical element)
110 Synthetic optical system 112 1/2 wave plate 114 Reflection mirror 116 Polarization beam splitter 200 Optical element 210 Multiple positive lenses (positive lens group)
220 lens array

Claims (17)

A light source optical system used with a plurality of excitation light sources that emit first colored light.
A wavelength conversion unit in which the first color light emitted from the plurality of excitation light sources is incident and emits a second color light having a wavelength different from that of the first color light.
A first optical system and a second optical system of positive power, which are sequentially provided on the optical path between the plurality of excitation light sources and the wavelength conversion unit,
Have,
The condensing point of each light flux emitted from the plurality of excitation light sources is formed between the first optical system and the second optical system.
A light source optical system characterized by that. It has an optical element for incidenting each light flux emitted from the plurality of excitation light sources into the first optical system as parallel light or convergent light.
The light source optical system according to claim 1. The optical element has a plurality of positive lenses corresponding to the plurality of excitation light sources.
The light source optical system according to claim 2. It has a plurality of collimator lenses in which each light flux emitted from the plurality of excitation light sources is incident on the plurality of positive lenses as parallel light or divergent light.
The light source optical system according to claim 3. At least half of the focusing points of the respective luminous fluxes emitted from the plurality of excitation light sources are located closer to the first optical system than to the second optical system.
The light source optical system according to any one of claims 1 to 4, wherein the light source optical system is characterized by the above. It is located on the optical path between the first optical system and the second optical system, and at the same time, it transmits one of the first polarization component and the second polarization component of the first color light and reflects the other. In addition, it has a polarizing optical element that transmits or reflects the second color light.
At least half of the focusing points of the respective luminous fluxes emitted from the plurality of excitation light sources are located between the first optical system and the polarizing optical element.
The light source optical system according to any one of claims 1 to 5. It is located on the optical path between the first optical system and the second optical system, and at the same time, it transmits one of the first polarization component and the second polarization component of the first color light and reflects the other. In addition, it has a polarizing optical element that transmits or reflects the second color light.
At least half of the focusing points of the light fluxes emitted from the plurality of excitation light sources are located closer to the first optical system than the second optical system with respect to the polarizing optical element. ,
The light source optical system according to any one of claims 1 to 5. It is located on the optical path between the first optical system and the second optical system, and at the same time, it transmits one of the first polarization component and the second polarization component of the first color light and reflects the other. In addition, it has a polarizing optical element that transmits or reflects the second color light.
The condensing point of the total luminous flux emitted from the plurality of excitation light sources is located closer to the wavelength conversion unit than the polarizing optical element in the optical path.
The light source optical system according to any one of claims 1 to 7. The condensing point of the total luminous flux emitted from the plurality of excitation light sources is located in the optical path so as to overlap with at least a part of the second optical system.
The light source optical system according to claim 8. The plurality of excitation light sources are arranged in a two-dimensional array, and the plurality of excitation light sources are arranged in a two-dimensional array.
It has a plurality of collimator lenses arranged in a two-dimensional array corresponding to the plurality of excitation light sources.
When the direction in which the divergence angle of the plurality of excitation light sources is maximized is defined as the X direction, the divergence angle in the X direction is θx, the pitch of the plurality of excitation light sources in the X direction is Px, and the plurality of excitation light sources. And when the distance between the plurality of collimator lenses is L, the following conditional equation (1) is satisfied.
The light source optical system according to any one of claims 1 to 9.
(1) 0.5 <Px / L · tanθx <2 The lens on the incident side of the second optical system has an aspherical surface or a free curved surface.
The light source optical system according to any one of claims 1 to 10. It is located on the optical path between the first optical system and the second optical system, and at the same time, it transmits the first color light and reflects the second color light, or reflects the first color light. It has a color separation optical element that transmits the second color light.
At least half of the focusing points of the respective luminous fluxes emitted from the plurality of excitation light sources are located between the first optical system and the color separation optical element.
The light source optical system according to any one of claims 1 to 5. It is located on the optical path between the first optical system and the second optical system, and at the same time, it transmits the first color light and reflects the second color light, or reflects the first color light. It has a color separation optical element that transmits the second color light.
At least half of the focusing points of the light fluxes emitted from the plurality of excitation light sources are located closer to the first optical system than the second optical system with respect to the color separation optical element. do,
The light source optical system according to any one of claims 1 to 5. It is located on the optical path between the first optical system and the second optical system, and at the same time, it transmits the first color light and reflects the second color light, or reflects the first color light. It has a color separation optical element that transmits the second color light.
The condensing point of the total luminous flux emitted from the plurality of excitation light sources is located closer to the wavelength conversion unit than the color separation optical element in the optical path.
The light source optical system according to any one of claims 1 to 5, 12, 12, and 13. A light source device having the plurality of excitation light sources and the light source optical system according to any one of claims 1 to 14. The plurality of excitation light sources emit coherent light as the first color light.
The light source device according to claim 15. With the plurality of excitation light sources,
The light source optical system according to any one of claims 1 to 14.
An image display element that modulates the light from the light source optical system to form an image, and
A projection optical system that magnifies and projects the image onto the projected surface,
An image projection device characterized by having.

Images