JP2022085838A - Light source optical system, light source unit, light source device, and image display device - Google Patents

Abstract

To provide a light source optical system which improves illuminance distribution using a simple configuration.SOLUTION: A light source optical system is provided, comprising a first optical system (22, 23, 24, 25, 30, 31, 32, 33) for guiding a first luminous flux emitted from a light source (20) to a wavelength conversion element (26), and a second optical system (23, 24, 25, 27, 30, 31, 32, 33) for a second luminous flux (LF) wavelength-converted by the wavelength conversion element to pass, the second optical system having light guide members (23, 30, 31, 32, 33) for separating a portion of the second luminous flux in the second optical system.SELECTED DRAWING: Figure 4

Description

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

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

Conventionally, a high-brightness ultra-high pressure mercury lamp or the like has been mainly used as a light source of a projector, but the life is short and maintenance needs to be performed frequently. Therefore, in recent years, the number of projectors that use a laser, LED, or the like as a light source instead of an ultra-high pressure mercury lamp is increasing. Lasers and LEDs have the advantages of having a longer life than ultra-high pressure mercury lamps and having good color reproducibility due to their monochromaticity.

For example, when the image display element is irradiated with the three primary colors of red, green, and blue to form an image, it is possible to generate all of these three colors with a laser light source, but a green laser or red is used. There is a problem that the light emission efficiency of the 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. A light source device using such a laser light source and a phosphor is disclosed in Patent Document 1, Patent Document 2, and the like.

Japanese Patent No. 6090875 Japanese Patent No. 6364916

This type of light source device is required to make the illuminance distribution on the irradiation surface as uniform as possible. The light source optical system in the conventional light source device has room for improvement in the bias of the illuminance distribution on the irradiation surface.

In particular, in a projector, the illuminance distribution on the image display element, which is the irradiation surface of the light from the light source optical system, may affect the illuminance distribution on the screen. Further, in addition to the light source optical system, the projection optical system and the like also affect the illuminance distribution. That is, the uneven illuminance on the screen, which is a problem of the projector, may be caused by the light source device or by the projection optical system or the like ahead of the light source device. As a case where the projection optical system contributes to the uneven illuminance, for example, in an ultra-short focus type projector in which the projection optical system includes a folded mirror, the incident angle at which the projected light is incident on the screen is the height position in the vertical direction. Since it varies greatly depending on the screen, uneven illumination is likely to occur at the top and bottom of the screen.

The present invention has been made based on the above awareness of the problem, and an object of the present invention is to provide a light source optical system, a light source unit, a light source device, and an image display device capable of improving the illuminance distribution with a simple configuration.

A mode of the light source optical system of the present invention is a first optical system in which a first light beam emitted from a light source is incident on a wavelength conversion element and a second light beam transmitted by the wavelength conversion element. It has an optical system, and the second optical system includes a light guide member that separates a part of the second light source in the second optical system.

In the embodiment of the light source unit of the present invention, the first light flux emitted from the light source is incident on the wavelength conversion element by the first optical system, and the second light flux converted by the wavelength conversion element is passed through the second optical system. A light guide member that emits light and separates a part of the second light flux in the second optical system is provided in the second optical system.

A mode of the light source device of the present invention is that the light source, the first optical system for incidenting the first light flux emitted from the light source on the wavelength conversion element, and the second light flux wavelength-converted by the wavelength conversion element are transmitted. It has two optical systems, and the second optical system includes a light guide member that separates a part of the second light source in the second optical system.

An aspect of the image display device of the present invention is to form a first optical system that forms an optical path through which a first light beam passes from a light source to a wavelength conversion element, and an optical path through which a second light beam that has been wavelength-converted by the wavelength conversion element passes. It has a light source device including a second optical system, an image display element that modulates the light from the light source device to form an image, and a projection optical system that projects an image onto a projected surface. In the optical system of the above, a light source member for separating a part of the second light source in the second optical system is provided.

According to the light source optical system, the light source unit, the light source device, and the image display device of the present invention, the illuminance distribution can be improved with a simple configuration.

It is a schematic block diagram of a projector (image display device). It is a schematic block diagram which shows the light source apparatus by 1st Embodiment. It is a figure which shows the structure of the phosphor wheel which constitutes a light source apparatus, (A) is a front view, (B) is a sectional view. It is a side sectional view which shows the arrangement and operation of the light guide member of 1st Embodiment. It is a front view which shows the arrangement of the light guide member of 1st Embodiment. It is a figure which shows the improvement result of the illuminance distribution by the light source apparatus of 1st Embodiment. It is a schematic block diagram which shows the light source apparatus by 2nd Embodiment. It is a side sectional view which shows the arrangement and operation of the light guide member of 2nd Embodiment. It is a front view which shows the arrangement of the light guide member of 2nd Embodiment. It is a figure which shows the improvement result of the illuminance distribution by the light source apparatus of 2nd Embodiment. It is a front view which shows the arrangement of the light guide member in the light source apparatus of 3rd Embodiment. It is a schematic block diagram which shows the light source apparatus by 4th Embodiment. It is a side sectional view which shows the arrangement and operation of the light guide member of 4th Embodiment. It is a front view which shows the arrangement of the light guide member of 4th Embodiment. It is a figure which shows the improvement result of the illuminance distribution by the light source apparatus of 4th Embodiment. It is a schematic block diagram which shows the light source apparatus by 5th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the overall structure of a projector which is an example of an image display device. 2 and later show embodiments of a light source device (light source optical system) constituting the projector. FIGS. 2 to 6 show the first embodiment, FIGS. 7 to 10 show the second embodiment, and FIG. 11 shows the first embodiment. 3 embodiments, FIGS. 12 to 15 are the fourth embodiment, and FIG. 16 is the fifth embodiment.

The projector 10 shown in FIG. 1 includes a housing 11, a light source device (light source unit) 12, a light homogenizing element 13, an illumination optical system 14, an image display element 15, and a projection optical system 16. ing. Each component from the light source device 12 to the projection optical system 16 is housed inside the housing 11.

The light source device 12 emits light including wavelengths corresponding to the respective colors of red (R), green (G), and blue (B), for example. The internal configuration of the light source device 12 will be described in detail later.

The light homogenizing element 13 equalizes by mixing the light emitted from the light source device 12. As the light homogenizing element 13, for example, a light tunnel in which four mirrors are combined, a rod integrator made of columnar glass or the like, a fly-eye lens in which a plurality of lenses are arranged in a matrix, or the like are used.

The illumination optical system 14 illuminates the image display element 15 substantially uniformly with the light homogenized by the light homogenizing element 13. The illumination optical system 14 has, for example, one or more lenses, one or more reflecting surfaces, and the like.

The image display element 15 has, for example, a light valve (optical valve) such as a digital micromirror device (DMD), a transmissive liquid crystal panel, and a reflective liquid crystal panel. The image display element 15 forms an image by modulating the light (light from the light source device 12) illuminated by the illumination optical system 14.

The projection optical system 16 magnifies and projects the image formed by the image display element 15 onto the screen (projected surface) 17 outside the projector 10. The projection optical system 16 has, for example, one or more lenses.

FIG. 2 is a schematic configuration diagram showing a light source device 12 according to the first embodiment. The light source device 12 includes a laser light source (light source) 20, a collimator lens 21, a first lens group 22, a light guide member 23, a 1/4 wavelength plate 24, and a second, which are arranged in order in the light propagation direction. It has two lens groups 25, a phosphor wheel (wavelength conversion element) 26, a third lens group 27, and a color wheel 28. For example, the light source optical system is configured by the components (optical elements) of the light source device 12 excluding the laser light source 20.

The laser light source 20 has a plurality of light sources (solid-state light sources). In FIG. 2, six light sources arranged in the vertical direction of the drawing are drawn, but in reality, six light sources are arranged in n rows (n is a number of 2 or more) in the direction orthogonal to the paper surface (depth direction). , 6 × n light sources are arranged in a two-dimensional array. The number of the plurality of laser light sources 20 can be arbitrarily set. It is also possible to use a single high-power laser light source instead of the plurality of laser light sources 20.

The plurality of laser light sources 20 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. Hereinafter, a plurality of light sources arranged in a two-dimensional array may be referred to as "plurality of laser light sources 20".

The plurality of laser light sources 20 are, for example, the center of emission intensity as the excitation light BL (first color light) that excites the phosphor provided in the fluorescence region 26d (FIG. 3) which is the wavelength conversion region of the phosphor wheel 26. Light in the blue band with a wavelength of 455 nm (blue laser light) is emitted. The blue laser light emitted from the plurality of laser light sources 20 is linearly polarized light having a constant polarization state, and is arranged so as to be S-polarized with respect to the incident surface (surface 23a described later) of the light guide member 23. .. The blue laser light emitted from the plurality of laser light sources 20 is coherent light. The excitation light BL emitted from the plurality of laser light sources 20 may be light having a wavelength that can excite the phosphor in the fluorescence region 26d of the phosphor wheel 26, and is limited to light in the blue band. is not.

A plurality of collimator lenses 21 are arranged in a two-dimensional array corresponding to a plurality of laser light sources 20. The plurality of collimator lenses 21 adjust each light flux (excitation light BL) emitted from the plurality of laser light sources 20 so as to be parallel light or convergent light. The number of collimator lenses 21 may be increased or decreased as long as it corresponds to the number of light sources of the laser light source 20 and can be increased or decreased according to the increase or decrease in the number of light sources of the laser light source 20.

The first lens group 22 has positive power as a whole, and has a positive lens 22a and a negative lens 22b in order from the laser light source 20 toward the light propagating direction toward the phosphor wheel 26. .. The first lens group 22 guides the excitation light BL incident from the collimator lens 21 as parallel light or convergent light to the light guide member 23 while converging. The first lens group 22 may have a negative power instead of a positive power.

The light guide member 23 is located on the optical path between the first lens group 22 and the second lens group 25. The light guide member 23 is a flat plate-shaped (plate type) polarizing beam splitter, and while reflecting S polarization (first polarization component) in the wavelength band of the excitation light BL derived from the first lens group 22, it is excited. A coating is applied so as to transmit the P polarization (second polarization component) of the wavelength band of the light BL and the fluorescent light YL (second color light) from the phosphor wheel 26.

In the present embodiment, the light guide member 23 reflects the S polarization in the wavelength band of the excitation light BL and transmits the P polarization, but on the contrary, it reflects the P polarization in the wavelength band of the excitation light BL. S polarized light may be transmitted.

The 1/4 wave plate 24 is arranged in a state where the optical axis is tilted by 45 degrees with respect to the linear polarization of the excitation light BL reflected by the light guide member 23. The 1/4 wave plate 24 converts the excitation light BL reflected by the light guide member 23 from linearly polarized light to circularly polarized light.

The second lens group 25 has a positive power as a whole, and has a positive lens 25a and a positive lens 25b in order from the laser light source 20 toward the light propagating direction toward the phosphor wheel 26. .. The second lens group 25 guides the excitation light BL, which is converted into circularly polarized light by the 1/4 wave plate 24 and incident, to the phosphor wheel 26 while converging.

The excitation light BL guided from the second lens group 25 is incident on the phosphor wheel 26. FIG. 3 is a diagram showing a detailed structure of the phosphor wheel 26. The phosphor wheel 26 has a disk member 26a and a drive motor 26c that rotationally drives the disk member 26a around a rotation shaft 26b. As the disk member 26a, for example, a transparent substrate or a metal substrate (aluminum substrate or the like) can be used, but the disk member 26a is not limited thereto.

Most of the disk member 26a of the phosphor wheel 26 in the circumferential direction (in the present embodiment, an angle range larger than 270 °) is partitioned into the fluorescent region 26d, and one of the circumferential directions excluding the range of the fluorescent region 26d. A portion (an angle range smaller than 90 ° in this embodiment) is partitioned into an excitation light reflection region 26e.

The fluorescent region 26d is configured by laminating a reflective coating 26d1, a phosphor layer 26d2, and an antireflection coating 26d3 in this order from the lower layer side to the upper layer side.

The reflection coat 26d1 has a property of reflecting light in the wavelength region of the fluorescent light YL by the phosphor layer 26d2. When the disk member 26a is made of a metal substrate having a high reflectance, it is possible to omit the reflection coat 26d1 (the disk member 26a has the function of the reflection coat 26d1).

As the fluorescent material layer 26d2, for example, a material in which a fluorescent material is dispersed in an organic / inorganic binder, a material in which crystals of the fluorescent material are directly formed, or a rare earth phosphor such as Ce: YAG type can be used. .. For the wavelength band of the fluorescent light YL by the phosphor layer 26dd2, for example, the wavelength bands of yellow, blue, green, and red can be used, but in the present embodiment, the case of using the fluorescent light YL having the yellow wavelength band is used. Illustrate. 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 coating 26d3 has a property of preventing the reflection of light on the surface of the phosphor layer 26d2.

A reflection coat 26e1 having a characteristic of reflecting light in the wavelength region of the excitation light BL derived from the second lens group 25 is laminated on the excitation light reflection region 26e. When the disk member 26a is made of a metal substrate having a high reflectance, it is possible to omit the reflection coat 26e1 (the disk member 26a has the function of the reflection coat 26e1).

By rotationally driving the disk member 26a by the drive motor 26c, the irradiation position of the excitation light BL on the phosphor wheel 26 moves with time. As a result, the excitation light BL incident on the phosphor wheel 26 is converted into fluorescent light YL having a wavelength different from that of the excitation light BL in the fluorescence region 26d and emitted, and the excitation light BL incident on the phosphor wheel 26 is emitted. Is time-divided into a state in which the excitation light BL is reflected and emitted as it is in the excitation light reflection region 26e.

The number and range of the fluorescence region 26d and the excitation light reflection region 26e 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.

The light source device 12 will be described again with reference to FIG. The excitation light BL reflected in the excitation light reflection region 26e of the phosphor wheel 26 becomes circularly polarized light in the opposite direction traveling from the phosphor wheel 26 toward the light guide member 23, and is substantially parallel to the diffused light beam by the second lens group 25. It is converted into a light beam and converted into P-polarized light by the 1/4 wave plate 24. The excitation light BL converted to P-polarization passes through the light guide member 23 and is incident on the color wheel 28 through the third lens group 27 having a condensing action. In the present embodiment, the third lens group 27 is composed of a single lens.

The excitation light BL incident on the fluorescent region 26d of the phosphor wheel 26 is converted into fluorescent light YL and emitted. This fluorescent light YL is converted from a diffused luminous flux to a substantially parallel luminous flux by the second lens group 25, passes through the 1/4 wave plate 24 and the light guide member 23, and is incident on the color wheel 28 through the third lens group 27. do.

The color wheel 28 has a disk member 28a and a drive motor 28c that rotationally drives the disk member 28a around a rotating shaft 28b. Although not shown, the disk member 28a has a blue region, a yellow region, a red region, and a green region partitioned in the circumferential direction. The blue region corresponds to the excitation light reflection region 26e of the phosphor wheel 26, and the yellow region, the red region, and the green region are synchronized so as to correspond to the fluorescence region 26d of the phosphor wheel 26, respectively. The yellow region transmits the yellow wavelength region emitted from the phosphor wheel 26 as it is. By using a dichroic mirror in each of the red region and the green region, light in an unnecessary wavelength region is reflected from the yellow wavelength to obtain high-purity color light.

As shown in FIG. 1, the light of each color created by time division by the color wheel 28 is guided (irradiated) from the light homogenizing element 13 to the image display element 15 through the illumination optical system 14, and the image corresponding to each color. Is formed and magnified and projected onto the screen 17 by the projection optical system 16 to obtain a color image. That is, the image display element 15 modulates the light from the light source device 12 to form an image, and the projection optical system 16 magnifies and projects the image formed by the image display element 15 onto the screen 17.

In the light source optical system of the light source device 12 constituting the projector 10 described above, the first lens group 22 to the second lens group 25 make the first light beam emitted from the laser light source 20 incident on the phosphor wheel 26. It becomes the first optical system (forming the optical path through which the first light source passes). The collimator lens 21 may be included in the first optical system.

Further, in the light source optical system of the light source device 12, the second lens group 25 to the third lens group 27 transmit the second luminous flux whose wavelength is converted by the phosphor wheel 26 (the optical path through which the second luminous flux passes). It becomes the second optical system (to be formed). The optical axis LX and the second luminous flux LF of the second optical system are shown in FIGS. 2, 4 and 5. FIG. 5 is a front view of the light guide member 23 seen from the phosphor wheel 26 side along the optical axis LX.

In the first optical system, the light guide member 23 functions as a reflecting element that reflects the first light flux incident from the first lens group 22 side toward the phosphor wheel 26 side. Further, in the second optical system, the light guide member 23 guides a part of the second luminous flux toward the third lens group 27 from the second lens group 25 to guide the light and separate it in the second optical system. Functions as an optical element. The configuration and function of the light guide member 23 will be described below.

The light guide member 23 has a parallel flat plate shape made of glass, a transparent resin, or the like, and has a front surface 23a and a back surface 23b that are parallel planes to each other on the front and back surfaces. In order for the light guide member 23 to function as a polarizing beam splitter, S polarization in the wavelength band of the excitation light BL is reflected on the surface 23a side, and P polarization and fluorescent light YL in the wavelength band of the excitation light BL are transmitted. Coat is formed.

The peripheral edge portion of the light guide member 23 includes a pair of parallel long side end faces (first end face) 23c and long side end faces (second end face) 23d extending in the longitudinal direction of the light guide member 23, and the light guide member 23. The long side end face 23c and the long side end face 23d, and the short side end face 23e and the short side end face 23f, which are composed of a pair of parallel short side end faces 23e and short side end faces 23f extending in the short side direction, are surface 23a, respectively. And a plane substantially perpendicular to the back surface 23b. Further, the long side end surface 23c and the long side end surface 23d are planes substantially perpendicular to the short side end surface 23e and the short side end surface 23f. The light guide member 23 is supported and fixed on the outside of the second luminous flux LF near the short side end faces 23e and 23f by a support means (not shown).

The direction in which the optical axis of the first lens group 22 extends is the M1 direction. The M1 direction is perpendicular to the optical axis LX of the second optical system. The light guide member 23 is arranged so as to face the longitudinal direction in the M1 direction and the M2 direction perpendicular to the optical axis LX.

As shown in FIG. 4, the light guide member 23 has a front surface 23a and a back surface 23b of about 45 degrees with respect to the optical axis LX when viewed from the side in the M2 direction (the side of the short side end surface 23e and the short side end surface 23f). It is arranged so as to be the intersection angle of. The front surface 23a is located on the phosphor wheel 26 (second lens group 25) side and the back surface 23b is located on the color wheel 28 (third lens group 27) side in the direction along the optical axis LX.

As shown in FIG. 5, in the front view of the light guide member 23 along the optical axis LX, the surface 23a and the long side end surface 23c face the phosphor wheel 26 side. The surface 23a having a large projected area in this front view is the first surface, the long side end surface 23c having a small projected area is the second surface, and the surface 23a, which is the first surface, fluoresces the first luminous flux. It is reflected on the body wheel 26 side.

When the light guide member 23 is viewed from the opposite side of FIG. 5 along the optical axis LX, the back surface 23b and the long side end surface 23d face the third lens group 27 (color wheel 28) side. The projected area in the rear view is larger on the back surface 23b than on the long side end surface 23d.

The light guide member 23 is arranged so that the optical axis LX passes through the center of the outer shape in the front view and the rear view. More specifically, in the front view of the light guide member 23 shown in FIG. 5, the optical axis LX is located at the center of the lateral dimension from the long side end surface 23c to the long side end surface 23d, and the short side end surface 23e to the short side. The optical axis LX is located at the center of the longitudinal dimension up to the end face 23f. As shown in FIG. 5, when the virtual plane S1 including the optical axis LX and along the M1 direction and the virtual plane S2 including the optical axis LX and along the M2 direction are set, the light guide member 23 in the front view and the rear view becomes , The shape is symmetric with respect to both the virtual plane S1 and the virtual plane S2 (the virtual plane S1 passes through the center of the light guide member 30 in the longitudinal direction, and the virtual plane S2 passes through the center in the lateral direction).

In the M1 direction, the entire lateral dimension of the light guide member 23 in the front view is within the range of the second luminous flux LF. That is, in the M1 direction, both the long side end surface 23c and the long side end surface 23d are located within the range of the optical path through which the second luminous flux LF passes.

In the M2 direction, the longitudinal dimension of the light guide member 23 is slightly larger than the luminous flux diameter of the second luminous flux LF, and a part of the vicinity of both ends in the longitudinal direction of the light guide member 23 is outside the range of the second luminous flux LF. Is located in.

Therefore, the front surface 23a and the back surface 23b, the long side end surface 23c, and the long side end surface 23d of the light guide member 23 are within the range of the second luminous flux LF except for a part near both ends in the M2 direction (longitudinal direction). positioned. On the other hand, the short side end surface 23e and the short side end surface 23f are located outside the range of the second luminous flux LF.

The second luminous flux LF containing the fluorescent light YL wavelength-converted in the fluorescent region 26d of the phosphor wheel 26 and the excitation light BL reflected in the excitation light reflection region 26e is substantially from the diffused flux by the second lens group 25. It is converted into a parallel luminous flux and reaches the light guide member 23. As shown in FIG. 5, most of the regions of the light guide member 23 located on the second light flux LF are the front surface 23a and the back surface 23b, and in the region, the light guide member 23 has the second light flux LF. As it is, it is transmitted toward the third lens group 27. The light guide member 23 further has a long side end surface 23c at a position where a part of the second light flux LF from the phosphor wheel 26 side is incident.

As shown in FIG. 4, a part of the second light flux LF is incident on the light guide member 23 from the long side end surface 23c, is propagated by repeating total reflection a plurality of times in the light guide member 23, and is propagated on the long side end surface. It is ejected from 23d. Specifically, the light incident on the light guide member 23 from the long side end surface 23c is reflected a plurality of times by the front surface 23a and the back surface 23b, respectively, and is guided to the long side end surface 23d. As described above, the light guide member 23 not only allows the second light flux LF to pass through the front surface 23a and the back surface 23b as it is, but also separates a part of the second light flux LF in the second optical system. As a result, in the second optical system, the light amount distribution in the second luminous flux LF is different before and after the light guide member 23.

More specifically, the light guide member 23 positions the long side end surface 23c on the incident side in one region in the M1 direction divided by the virtual plane S2 shown in FIG. 5, and in the other region in the M1 direction on the injection side. The long side end surface 23d is positioned. Therefore, the light guide member 23 guides a part of the second luminous flux LF from the above one region sandwiching the virtual plane S2 to the other region.

By providing the light guide member 23 functioning as described above in the second optical system, it is possible to change the illuminance distribution on the irradiation surface (image display element 15) of the illumination light emitted from the light source device 12. can. Then, by appropriately managing the direction and degree of the light guide by the light guide member 23, the illuminance distribution on the irradiation surface (image display element 15) can be improved.

The light guide member 23 reflects the first luminous flux emitted from the laser light source 20 in the first optical system toward the phosphor wheel 26, and is provided in the second optical system to provide the second luminous flux LF. Separate a part of. Therefore, it is possible to improve the illuminance distribution by a simple configuration with a small number of parts.

A part of the light guide of the second light flux LF by the light guide member 23 is performed within the range of the optical path of the second optical system (inside the light flux diameter of the second light flux LF). Therefore, it is possible to prevent the light amount loss caused by the light guide in the light guide member 23 and improve the illuminance distribution without lowering the light utilization efficiency in the light source device 12.

In addition, the effect of increasing the range of change in the illuminance distribution can be obtained by totally reflecting the light light a plurality of times when the light guide member 23 guides the light.

As shown in FIG. 5, the light guide member 23 has a size in the longitudinal direction crossing the light flux diameter of the second light flux LF. Therefore, in the longitudinal direction (M2 direction) of the light guide member 23, the effect of the light guide member 23 can be obtained in the entire second light flux LF.

In the projector 10, there is a correlation between the illuminance distribution of the illumination light at the location of the image display element 15 and the illuminance distribution on the screen 17. Then, by setting the light separation action of the light guide member 23 in the second optical system in consideration of the influence of the projection optical system 16 and the like on the illuminance distribution, not only the light source device 12 but also the entire projector 10 is set. It is possible to improve the light distribution characteristics of the screen 17 and reduce the uneven illuminance on the screen 17.

The results of experiments and measurements demonstrating the effect of the light guide member 23 are shown in FIG. In FIG. 6, an embodiment in which a part of the second light flux LF is separated (light guide) by using the light guide member 23 and a second light flux LF are separated (light guide) by the light guide member 23. The illuminance distribution on the screen 17 is shown for each of the non-comparative examples. In the embodiment, the long side end surface 23c and the long side end surface 23d of the light guide member 23 are configured as light transmission surfaces, and light is incident from the long side end surface 23c into the light guide member 23 and from the long side end surface 23d. It is designed to emit light. In the comparative example, the long side end surface 23c and the long side end surface 23d of the light guide member 23 are configured as light absorption surfaces, and the light incident from the long side end surface 23c into the light guide member 23 and the light from the long side end surface 23d. I am trying to prevent the emission of light. When projection was performed on the screen 17 under the same conditions other than this, the illuminance distribution shown in FIG. 6 was obtained.

As can be seen from FIG. 6, in the examples, the variation in the illuminance distribution is smaller than in the comparative example, and the illuminance unevenness on the screen 17 is improved. In particular, in the region from the center to the upper left portion of the screen 17, the lack of light amount that has occurred in the comparative example is improved in the example.

As an example, the evaluation of the illuminance distribution on the screen 17 is performed as follows. First, the maximum value of the illuminance on the screen 17 is standardized as 100%. Then, the range in which the projection by the projector 10 is performed on the screen 17 is equally divided into nine rectangular regions, and the average value of the illuminance is calculated for each region. Further, the average value of the illuminance in the nine regions is calculated. By referring to the values calculated in this way, the unevenness of the illuminance on the screen 17 can be quantitatively evaluated.

Table 1 in FIG. 6 shows the average value of the illuminance of each of the nine regions on the screen 17 in the example, and Table 2 shows the illuminance of each of the nine regions on the screen 17 in the comparative example. Shows the average value of. The average value of the illuminance calculated based on the data in Tables 1 and 2 is 88.0% in the example and 86.9% in the comparative example, and the illuminance on the screen 17 in the example is compared with the comparative example. The unevenness of the distribution is reduced.

Further, in this embodiment, the angle formed by the normal of the second surface (long side end surface 23c) of the light guide member 23 and the optical axis LX of the second optical system is 45 degrees, and the light guide member 23 The average value W ₃ of the lengths of the second surface (long side end surface 23c) in the direction perpendicular to the ridge line between the first surface (surface 23a) and the second surface (long side end surface 23c) is 0.9 mm. The diameter φ _L of the second light beam LF at the position of the ridge line between the first surface (surface 23a) and the second surface (long side end surface 23c) of the light guide member 23 of the second optical system is 20 mm. be. The diameter φ L of the second luminous flux LF is the diameter φ _L of the second luminous flux LF in the plane perpendicular to the optical axis LX at the end position on the phosphor wheel 26 (wavelength conversion element) side of the light guide member 23. The diameter (luminous flux diameter).
here,
With the light guide member projected onto a plane perpendicular to the optical axis of the second optical system, the average value of the lengths of the second planes in the direction perpendicular to the ridgeline of the first plane and the second plane is calculated. W ₂ ,
The diameter of the second luminous flux on the optical surface immediately before the light guide member of the second optical system is φ _L ,
The distance between the optical axis of the second optical system and the center line of the long side of the incident side surface ( _23c ) of the long side end faces of the light guide member is set to Hi.
The distance between the optical axis of the second optical system and the center line of the long side of the injection side surface (23d) of the long side end faces of the light guide member is _Ho .
When
W ₂ = 0.64 mm
φ _L = 20 mm
Hi ₌ 7.07 mm
Ho = _7.07 mm
Will be. Therefore,
W ₂ / φ _L = 0.032
Will be.

W ₂ / φ _L is a measure of the amount of light guided by the light guide member, and it is desirable that the following conditional expression (1) is satisfied.
(1) 0.018 <W ₂ / φ _L <0.035

When W ₂ / φ _L is smaller than 0.018, the amount of light guided is too small to obtain the effect. When W ₂ / φ _L is larger than 0.032, the amount of light guided is too large and there is a high possibility that the luminous flux will be adversely affected.

More preferably, it is preferable to satisfy the following conditional expression (2).
(2) 0.022 <W ₂ / φ _L <0.033

The evaluation of the illuminance distribution on the screen 17 may be performed by a method different from the above. For example, the number of regions on the screen 17 for obtaining the average value of the illuminance can be set to other than nine. Further, the shape of each region on the screen 17 can be made into a shape other than the equally divided rectangle.

FIG. 7 is a schematic configuration diagram showing the light source device 12 according to the second embodiment. The light source device 12 of the second embodiment includes a light guide member 30 instead of the light guide member 23 of the first embodiment.

The light guide member 30 is arranged eccentrically with respect to the optical axis LX in the traveling direction (M1 direction) of the first light flux from the laser light source 20 toward the light guide member 30. The light guide member 30 is not a polarized beam splitter like the light guide member 23, but a dichroic mirror that reflects light in the wavelength band of the excitation light BL and transmits light in the wavelength band of the fluorescent light YL. A 1/4 wave plate is not provided between the light guide member 30 and the second lens group 25. The above is the difference between the first embodiment and the second embodiment. Other configurations are the same as those of the light source device 12 of the first embodiment, and the description of common parts will be omitted.

The light guide member 30 has a parallel flat plate shape made of glass, a transparent resin, or the like, and has a front surface 30a and a back surface 30b that are parallel to each other. The surface 30a side is coated with a coating that reflects light in the wavelength band of the excitation light BL and transmits light in the wavelength band of the fluorescent light YL so that the light guide member 30 functions as a dichroic mirror.

As shown in FIG. 9, when the virtual plane S1 including the optical axis LX and along the M1 direction and the virtual plane S2 including the optical axis LX and along the M2 direction are set, the front view and the rear view along the optical axis LX are set. The light guide member 30 has a shape symmetrical with respect to the virtual plane S1 (the virtual plane S1 passes through the center of the light guide member 30 in the longitudinal direction). On the other hand, the light guide member 30 in the front view and the rear view does not overlap with the virtual plane S2 and is located at a position deviated from the optical axis LX in the M1 direction.

The first light beam emitted from the laser light source 20 is incident on the phosphor wheel 26 by the first optical system from the first lens group 22 to the second lens group 25. Further, the second light beam wavelength-converted by the phosphor wheel 26 is incident on the color wheel 28 through the second optical system from the second lens group 25 to the third lens group 27. In the second optical system, only the fluorescent light YL passes through the light guide member 30 in the region where the light guide member 30 is arranged, and the fluorescent light YL and the excitation light BL are transmitted in the region where the light guide member 30 is not arranged. Both reach the color wheel 28. Since the light guide member 30 is eccentrically arranged in the M1 direction with respect to the optical axis LX, the excitation light BL can pass through a wide region including the vicinity of the optical axis LX in the second optical system.

As shown in FIGS. 8 and 9, the peripheral edge portion of the light guide member 30 includes a pair of parallel long side end faces (first end face) 30c and long side end faces (second end face) 30d extending in the longitudinal direction. The long side end face 30c and the long side end face 30d, and the short side end face 30e and the short side end face 30f, which are composed of a pair of parallel short side end faces 30e and short side end faces 30f extending in the short side direction, are surface 30a, respectively. And a surface substantially perpendicular to the back surface 30b. Further, the long side end surface 30c and the long side end surface 30d are planes substantially perpendicular to the short side end surface 30e and the short side end surface 30f. The light guide member 30 is supported and fixed on the outside of the second luminous flux LF near the short side end faces 30e and 30f by a support means (not shown).

As shown in FIG. 8, the light guide member 30 has a front surface 30a and a back surface 30b of about 45 degrees with respect to the optical axis LX when viewed from the side in the M2 direction (the side of the short side end surface 30e and the short side end surface 30f). It is arranged so that it is at the angle of. The front surface 30a is located on the phosphor wheel 26 (second lens group 25) side and the back surface 30b is directed on the color wheel 28 (third lens group 27) side in the direction along the optical axis LX.

As shown in FIG. 9, in the front view of the light guide member 30 along the optical axis LX, the surface 30a and the long side end surface 30c face the phosphor wheel 26 side. The surface 30a having a large projected area in this front view is the first surface, the long side end surface 30c having a small projected area is the second surface, and the surface 30a, which is the first surface, fluoresces the first luminous flux. It is reflected on the body wheel 26 side.

When the light guide member 30 is viewed from the opposite side of FIG. 9 along the optical axis LX, the back surface 30b and the long side end surface 30d face the third lens group 27 (color wheel 28) side. The projected area in the rear view is larger on the back surface 30b than on the long side end surface 30d.

In the M1 direction, the entire lateral dimension of the light guide member 30 in the front view is within the range of the second luminous flux LF. That is, in the M1 direction, both the long side end surface 30c and the long side end surface 30d are located within the range of the optical path through which the second luminous flux LF passes.

In the M2 direction, the longitudinal dimension of the light guide member 30 is slightly larger than the luminous flux diameter of the second luminous flux LF, and a part of the vicinity of both ends in the longitudinal direction of the light guide member 30 is outside the range of the second luminous flux LF. Is located in.

Therefore, the front surface 30a and the back surface 30b, the long side end surface 30c, and the long side end surface 30d of the light guide member 30 are within the range of the second luminous flux LF except for a part near both ends in the M2 direction (longitudinal direction). positioned. On the other hand, the short side end surface 30e and the short side end surface 30f are located outside the range of the second luminous flux LF.

As shown in FIG. 8, a part of the second luminous flux LF is incident on the light guide member 30 from the long side end surface 30c, is propagated by repeating total reflection a plurality of times in the light guide member 30, and is propagated on the long side end surface. It is ejected from 30d. That is, the light guide member 30 separates a part of the second luminous flux LF in the second optical system. As a result, in the second optical system, the light amount distribution in the second luminous flux LF is different before and after the light guide member 30.

Unlike the light guide member 23 of the first embodiment, the light guide member 30 is arranged eccentrically in the M1 direction without intersecting the optical axis LX. The long side end surface 30c on which a part of the second luminous flux LF is incident is located near the peripheral edge of the second luminous flux LF. Further, the long side end surface 30d from which the light propagating in the light guide member 30 is emitted is located near the center near the optical axis LX. Therefore, the light guide member 30 functions to bring a part of the light passing through the peripheral edge side of the second luminous flux LF closer to the optical axis LX in the M1 direction. In other words, the light guide member 30 in the second optical system has an effect of adjusting the illuminance distribution so as to brighten the vicinity of the center of the image display element 15 and the screen 17.

The light guide member 30 has a size in the longitudinal direction crossing the light flux diameter of the second light flux LF. Therefore, in the longitudinal direction (M2 direction) of the light guide member 30, the effect of the light guide member 30 can be obtained in the entire second light flux LF.

The results of experiments and measurements demonstrating the effect of the light guide member 30 are shown in FIG. In FIG. 10, the light guide member 30 is used to separate (light guide) a part of the second luminous flux LF, and the light guide member 30 is not used to separate (light guide) the image display element 15. The illuminance distribution on the screen 17 with each of the comparative examples is shown. In the embodiment, the long side end surface 30c and the long side end surface 30d of the light guide member 30 are configured as light transmitting surfaces, and light is incident from the long side end surface 30c into the light guide member 30 and from the long side end surface 30d. It is designed to emit light. In the comparative example, the long side end surface 30c and the long side end surface 30d of the light guide member 30 are configured as light absorption surfaces, and the light incident from the long side end surface 30c into the light guide member 30 and the light from the long side end surface 30d. I am trying to prevent the emission of light. When projection was performed on the screen 17 under the same conditions other than this, the illuminance distribution shown in FIG. 10 was obtained.

As can be seen from FIG. 10, in the examples, the variation in the illuminance distribution is smaller than in the comparative example, and the illuminance unevenness on the screen 17 is improved. In particular, in the region near the upper center of the screen 17, the range in which a higher amount of light can be obtained in the examples is wider than in the comparative example.

The unevenness of the illuminance on the screen 17 was evaluated by the same evaluation criteria as in the first embodiment. Table 3 in FIG. 10 shows the average value of the illuminance of each of the nine regions on the screen 17 in the example, and Table 4 shows the illuminance of each of the nine regions on the screen 17 in the comparative example. Shows the average value of. In the second embodiment, the average value of the illuminance calculated based on the data in Tables 3 and 4 is 90.8% in the example and 90.0% in the comparative example, and the screen in the example is compared with the comparative example. The unevenness of the illuminance distribution on 17 is reduced.

Further, in this embodiment, the angle formed by the normal of the second surface (long side end surface 30c) of the light guide member 30 and the optical axis LX is 45 degrees, and the first surface (surface) of the light guide member 30 is formed. The average value W ₃ of the lengths of the second surface (long side end surface 30c) in the direction perpendicular to the ridge line between the second surface (long side end surface 30c) is 0.7 mm, and the second optical The diameter _φL of the second light flux LF at the position of the ridge line between the first surface (surface 30a) and the second surface (long side end surface 30c) of the light guide member 30 of the system is 20 mm. The diameter φ L of the second luminous flux LF is the diameter φ _L of the second luminous flux LF in the plane perpendicular to the optical axis LX at the end position on the phosphor wheel 26 (wavelength conversion element) side of the light guide member 30. The diameter (luminous flux diameter).
Therefore,
W ₂ = 0.49 mm
φ _L = 20 mm
Hi ₌ 8.04 mm
Ho = _0.96 mm
Will be. Therefore,
W ₂ / φ _L = 0.025
Therefore, the above conditional expressions (1) and (2) are satisfied.

The third embodiment of the light source device 12 shown in FIG. 11 shows only the arrangement of the light guide member 31 in the front view (and the rear view) along the optical axis LX. The configuration other than the light guide member 31 is the same as that of the second embodiment, and the illustration and description of the common portion are omitted.

The light guide member 31 has a parallel flat plate shape formed of glass, a transparent resin, or the like, and has a front surface 31a, a back surface 31b, a long side end face (first end face) 31c, and a long side end face (second end face) 31d. The short side end surface 31e and the short side end surface 31f are surfaces corresponding to the respective surfaces 30a to 30f in the light guide member 30 of the second embodiment, respectively.

The light guide member 31 has an asymmetric shape with respect to both the virtual plane S1 including the optical axis LX and along the M1 direction and the virtual plane S2 including the optical axis LX and along the M2 direction. More specifically, the light guide member 31 is arranged eccentrically with respect to the optical axis LX in the M1 direction (without overlapping with the virtual plane S2), similarly to the light guide member 30 of the second embodiment. The light guide member 31 further positions the short side end surface 31e closer to the virtual plane S2 than the short side end surface 31f, and the short side end surface 31e is located within the range of the second luminous flux LF. That is, the light guide member 31 has a shape asymmetric with respect to the position of the optical axis LX of the second optical system (virtual plane S1) in the direction in which the long side end surface 31c and the long side end surface 31d extend (M2 direction). .. Then, in the M2 direction, there is a region where the light guide member 31 is located in the second light flux LF and can be guided, and a region where the light guide member 31 does not overlap with the second light flux LF and does not guide light. exist. The light guide member 31 is supported and fixed in the vicinity of the short side end surface 31f outside the range of the second luminous flux LF by a support means (not shown).

The virtual plane S1 includes the optical axis LX of the second optical system, and also includes light flux before and after being separated (guided) by the light guide member 31 (long-side end surface 31c and long-side end surface 31d are traversed). It is a plane. By including such asymmetry with respect to the virtual plane S1 (asymmetry with respect to the optical axis LX in the M2 direction) in the requirement for setting the position of the light guide member 31, the illuminance distribution on the image display element 15 and the screen 17 can be changed. The degree of freedom is improved.

The light guide member 31 shown in FIG. 11 has an asymmetrical shape with respect to both the virtual plane S1 and the virtual plane S2, but has a symmetrical shape with respect to the virtual plane S2 and is asymmetrical only with respect to the virtual plane S1. It is also possible to use a light guide member having a shape.

FIG. 12 is a schematic configuration diagram showing the light source device 12 according to the fourth embodiment. The light source device 12 of the fourth embodiment differs from the third embodiment only in the arrangement of the light guide member 32. It is the same as the third embodiment except for the arrangement of the light guide member 32, and the description of the common portion will be omitted.

13 and 14 are diagrams illustrating the arrangement of the light guide member 32 according to the fourth embodiment. The front surface 32a, the back surface 32b, the long side end surface 32c, the long side end surface 32d, the short side end surface 32e, and the short side end surface 32f of the light guide member 32 shown in FIGS. 13 and 14 are the respective surfaces 31a to 31f of the light guide member 31, respectively. It is a side corresponding to. The light guide member 32 of the fourth embodiment is arranged in the third embodiment in that the light guide member 32 is arranged on the first optical system side of the virtual plane S2 along the M2 direction including the optical axis LX. Is different. Other configurations are the same as those of the light source device 12 of the third embodiment, and the description of common parts will be omitted. The light guide member 32 is supported and fixed in the vicinity of the short side end surface 32f outside the range of the second luminous flux LF by a support means (not shown).

As shown in FIG. 13, a part of the second light flux LF is incident on the light guide member 32 from the long side end surface 32c, is propagated by repeating total reflection a plurality of times in the light guide member 32, and is propagated on the long side end surface. It is ejected from 32d. That is, the light guide member 32 separates a part of the second luminous flux LF in the second optical system. As a result, in the second optical system, the light amount distribution in the second luminous flux LF is different before and after the light guide member 32.

As shown in FIG. 13, in the light guide member 32, the long side end surface 32c to which a part of the second luminous flux LF is incident is located near the center near the optical axis LX. Further, the long side end surface 32d from which the light propagating in the light guide member 32 is emitted is located near the peripheral edge of the second luminous flux LF. Therefore, the light guide member 32 functions to keep a part of the light passing through the center side of the second luminous flux LF away from the optical axis LX in the M1 direction. In other words, the light guide member 32 in the second optical system has an effect of adjusting the illuminance distribution so as to brighten the vicinity of the periphery of the image display element 15 and the screen 17.

FIG. 15 is a diagram showing the results of experiments and measurements demonstrating the effect of the light guide member 32 of the fourth embodiment. In FIG. 15, the light guide member 32 is used to separate (light guide) a part of the second luminous flux LF, and the light guide member 32 is not used to separate (light guide) the image display element 15. The illuminance distribution on the screen 17 with each of the comparative examples is shown. In the embodiment, the long side end surface 32c and the long side end surface 32d of the light guide member 32 are configured as light transmission surfaces, and light is incident from the long side end surface 32c into the light guide member 32 and from the long side end surface 32d. It is designed to emit light. In the comparative example, the long side end surface 32c and the long side end surface 32d of the light guide member 32 are configured as light absorption surfaces, and the light incident from the long side end surface 32c into the light guide member 32 and the light from the long side end surface 32d. I am trying to prevent the emission of light. When projection was performed on the screen 17 under the same conditions other than this, the illuminance distribution shown in FIG. 15 was obtained.

As can be seen from FIG. 15, in the examples, the variation in the illuminance distribution is smaller than in the comparative example, and the illuminance unevenness on the screen 17 is improved. In particular, in the region near the upper center of the screen 17, the range in which a higher amount of light can be obtained in the examples is wider than in the comparative example.

The unevenness of the illuminance on the screen 17 was evaluated by the same evaluation criteria as in the first embodiment. Table 5 in FIG. 15 shows the average value of the illuminance of each of the nine regions on the screen 17 in the example, and Table 6 shows the illuminance of each of the nine regions on the screen 17 in the comparative example. Shows the average value of. In the fourth embodiment, the average value of the illuminance calculated based on the data in Tables 5 and 6 is 89.4% in the example and 89.1% in the comparative example, and the screen in the embodiment is compared with the comparative example. The unevenness of the illuminance distribution on 17 is reduced.

Further, in this embodiment, the angle formed by the normal of the second surface (long side end surface 32c) of the light guide member 32 and the optical axis (LX) of the second optical system is 45 degrees, and the light guide member The average value W ₃ of the lengths of the second surface (long side end surface 32c) in the direction perpendicular to the ridge line of the first surface (surface 32a) and the second surface (long side end surface 32c) of 32 is 0. 7 mm, the diameter φ of the second light beam (LF) at the position of the ridge line between the first surface (surface 32a) and the second surface (long side end surface 32c) of the light guide member 32 of the second optical system. _L is 21 mm. The diameter φL of the second luminous flux LF is the diameter _φL of the second luminous flux LF in the plane perpendicular to the optical axis LX at the end position on the phosphor wheel 26 (wavelength conversion element) side of the light guide member 32. The diameter (luminous flux diameter).
Therefore,
W ₂ = 0.49 mm
φ _L = 21 mm
Hi ₌ 0.96 mm
Ho = _8.04 mm
Will be. Therefore,
W ₂ / φ _L = 0.024
Therefore, the above conditional expressions (1) and (2) are satisfied.
In addition, Hi / φ _{L =} 0.046
Will be.

H _i / φ _L is an index indicating which position in the light flux the region separated in the second light flux by the light guide member passes through, and the light guide member guides the region away from the optical axis. In this case, it is desirable to satisfy the following conditional expression (3).
(3) _Hi / φ _L <0.1

Generally, in the second luminous flux LF, the amount of light is large in the vicinity of the optical axis LX. Therefore, when guiding the light away from the optical axis LX by the light guide member, guiding the light from the vicinity of the optical axis LX reduces illuminance unevenness. Easy to adjust to. If it is larger than 0.1, it will be separated from the vicinity of the optical axis LX, and it will be difficult to reduce the uneven illuminance.

In the fourth embodiment, since the arrangement of the light guide member 32 guides the light in the central portion (the portion near the optical axis LX) in the second luminous flux LF to the peripheral portion (the portion far from the optical axis LX), the light flux The distribution of the luminous flux LF can be adjusted when the amount of light in the central portion of the LF is strong. Thereby, the illuminance distribution of the image display element 15 and the screen 17 can be uniformly adjusted.

FIG. 16 is a schematic configuration diagram showing the light source device 12 according to the fifth embodiment. In the light source device 12 of the fifth embodiment, the arrangement of the light guide member 33 guides the light in the central portion (the portion near the optical axis LX) of the second luminous flux LF to the peripheral portion (the portion far from the optical axis LX). It is common with the fourth embodiment in that it shines. The front surface 33a, the back surface 33b, the long side end surface 33c, and the long side end surface 33d of the light guide member 33 are surfaces corresponding to the respective surfaces 32a to 32d of the light guide member 32, respectively.

In the fifth embodiment, the angle formed by the optical axis LX and the normal of the second surface (long side end surface 33c) of the light guide member 33 is 35 degrees, and the first surface (surface 33a) of the light guide member 33 is set to 35 degrees. A point where the optical axis of the first optical system is tilted by 20 degrees so that the first light flux reflected by the light beam is incident on the wavelength conversion element (phosphor wheel 26) (first surface (surface 33a) of the light guide member 33). ) Is tilted so that the incident angle is 55 degrees), which is different from the fourth embodiment. That is, the normal of the second surface (long side end surface 33c) of the light guide member 33 is closer to the direction of the optical axis LX of the second optical system than in the fourth embodiment. Further, the normal of the first surface (surface 33a) of the light guide member 33 is away from the direction of the optical axis LX of the second optical system. That is, the angle between the normal of the second surface (long side end surface 33c) and the optical axis LX of the second optical system is 35 degrees, and the normal of the first surface (surface 33a) and the second surface. The angle formed by the optical axis LX is 55 degrees. Therefore, the angle formed by the normal of the second surface (long side end surface 33c) and the optical axis LX of the second optical system is the normal of the first surface (surface 33a) and the light of the second optical system. It is made smaller than the angle formed by the axis LX. Other configurations are the same as those of the light source device 12 of the fourth embodiment, and the description of common parts will be omitted.

As shown in FIG. 16, the arrangement of the laser light source 20, the collimator lens 21, and the first lens group 22 is adjusted so as to match the arrangement of the light guide member 33. The excitation light BL emitted from the first lens group 22 is reflected by the first surface (surface 33a) of the light guide member 33 and is incident on the second lens group 25 along the optical axis LX.

In the light source device 12 of the fifth embodiment, the angle formed by the normal of the second surface (long side end surface 33c) of the light guide member 33 and the optical axis LX is 35 degrees, and the first of the light guide member (33). The average value W3 of the lengths of the _second surface (long side end surface 33c) in the direction perpendicular to the ridge line of the surface (surface 33a) and the second surface (long side end surface 33c) is 0.7 mm, and the second The diameter φ _L of the second light beam LF at the position of the ridge line between the first surface (surface 33a) and the second surface (long side end surface 33c) of the light guide member 33 of the optical system is 20 mm. The diameter φ L of the second luminous flux LF is the diameter φ _L of the second luminous flux LF in the plane perpendicular to the optical axis LX at the end position on the phosphor wheel 26 (wavelength conversion element) side of the light guide member 33. The diameter (luminous flux diameter).
Therefore,
W ₂ = 0.57 mm
φ _L = 20 mm
Hi ₌ 1.63 mm
Ho = _7.37 mm
Will be. Therefore,
W ₂ / φ _L = 0.029
Therefore, the above conditional expressions (1) and (2) are satisfied.

In addition, Hi / φ _{L =} 0.082
Therefore, the above conditional expression (3) is satisfied.

In the light source device 12 of the fifth embodiment, the angle formed by the normal of the second surface (long side end surface 33c) of the light guide member 33 and the optical axis LX of the second optical system is set to the first surface (surface). By making the angle smaller than the angle formed by the normal line of 33a) and the optical axis LX of the second optical system, the light is incident on the second surface (long side end surface 33c) of the total light amount of the second luminous flux LF and guided. The amount of light guided by the optical member 33 can be increased. As a result, W ₂ / φ _L can be made large. Therefore, in the light source device 12 of the fifth embodiment, the light amount distribution of the luminous flux LF can be adjusted more efficiently by the light guide member 33.

In each of the above embodiments, the long side end faces 23c (30c, 31c, 32c, 33c) and the long side end faces 23d (30d, 31d, 32d, 33d) of the light guide member 23 (30, 31, 32, 33) are parallel to each other. Is. This configuration is preferable because the directions of the incident and the emitted light separated by the light guide member 23 (30, 31, 32, 33) in the second optical system are aligned. However, the relationship between the first end surface corresponding to the long side end surface 23c (30c, 31c, 32c, 33c) and the second end surface corresponding to the long side end surface 23d (30d, 31d, 32d, 33d) is non-parallel. It is also possible to.

In each of the above embodiments, the long side end faces 23c (30c, 31c, 32c, 33c) and the long side end faces 23d (30d, 31d, 32d, 33d) of the light guide member 23 (30, 31, 32, 33) are It is a plane perpendicular to the front surface 23a (30a, 31a, 32a, 33a) and the back surface 23b (30b, 31b, 32b, 33b). Then, in the first to fourth embodiments, the long side end faces 23c (30c, 31c, 32c) and the long side end faces 23d (30d, 31d, 32d) are approximately about the optical axis LX of the second optical system. It will be arranged at 45 degrees. Unlike this, the angle of the first end face and the second end face of the light guide member can be set to an angle other than 45 degrees with respect to the optical axis LX. For example, as in the fifth embodiment, the angle of the first end face and the second end face with respect to the optical axis LX is set to be larger than 45 degrees (angled) so that the view along the optical axis LX can be seen. The projected area at the time is increased, and the ratio of the second light flux LF separated by the light guide member can be increased.

The present invention is particularly useful in an image display device (projector) that projects an image onto a surface to be projected, but can be applied to other than the image display device as long as the improvement of the illuminance distribution is required. That is, the present invention can be applied as a light source optical system, a light source unit, a light source device, or the like, which does not include a projection optical system or the like as a component. Further, in the light source optical system, the light source unit, and the light source device of the present invention, the light emitted from the light source may be used for other than the projection of the image.

Each of the above embodiments is an application example to a projector, and the illuminance distribution on the screen on which the image is projected by the projector is used as an evaluation standard as shown in FIGS. 6 and 10, but the illuminance distribution is improved in a place other than the screen. May be determined. For example, the performance evaluation of the light source optical system, the light source unit, and the light source device is performed by measuring the illuminance distribution at the location of the image display element 15 of the above embodiment (the irradiation surface irradiating the light from the light source device 12). Is also possible.

The light source device 12 of the above embodiment emits light of a plurality of colors in a time division, but the light source device and the light source unit of the present invention are not limited to the type that emits light of a plurality of colors in a time division.

Although the present invention has been described above with reference to embodiments and modifications based on the accompanying drawings, the present invention is not limited to the above-described embodiments and modifications, and various changes and applications can be made without departing from the gist. It is possible. In the above-described embodiment, the configuration and the like shown in the attached drawings are not limited to this, and can be appropriately changed within the range in which the effect of the present invention is exhibited. In addition, it can be appropriately modified and implemented as long as it does not deviate from the gist of the present invention.

10 Projector (image display device)
12 Light source device (light source unit)
13 Light homogenizing element 14 Illumination optical system 15 Image display element 16 Projection optical system 17 Screen (projected surface)
20 Laser light source (light source)
21 Collimator lens 22 First lens group (first optical system)
23 Light guide member (first optical system, second optical system)
23a surface (first surface)
23b Back side 23c Long side end face (second face, first end face)
23d long edge end face (second end face)
24 1/4 wave plate (first optical system, second optical system)
25 Second lens group (first optical system, second optical system)
26 Fluorescent wheel (wavelength conversion element)
27 Third lens group (second optical system)
28 Color wheel 30 Light guide member (first optical system, second optical system)
30a surface (first surface)
30b Back side 30c Long side end face (second face, first end face)
30d long edge end face (second end face)
31 Light guide member (first optical system, second optical system)
31a surface (first surface)
31b Back side 31c Long side end face (second face, first end face)
31d long edge end face (second end face)
32 Light guide member (first optical system, second optical system)
32a surface (first surface)
32b Back side 32c Long side end face (second face, first end face)
32d long edge end face (second end face)
33 Light guide member (first optical system, second optical system)
33a surface (first surface)
33b Back side 33c Long side end face (second face, first end face)
33d long edge end face (second end face)
LF 2nd luminous flux LX Optical axis of the 2nd optical system

Claims (14)

A first optical system that causes the first luminous flux emitted from the light source to enter the wavelength conversion element, and
A second optical system through which the second luminous flux converted by the wavelength conversion element is transmitted, and
It is a light source optical system having
A light source optical system comprising, in the second optical system, a light guide member that separates a part of the second luminous flux in the second optical system. The light source member has a first surface having a large projected area and a second surface having a small projected area as seen along the optical axis of the second optical system from the wavelength conversion element side, and the separation thereof. The light source optical system according to claim 1, wherein a part of the second light beam is incident on the second surface. The light source optical system according to claim 2, wherein the light source optical system satisfies the following conditional expression.
0.018 <W ₂ / φ _L <0.035
here,
W ₂ is a state in which the light guide member is projected onto a surface perpendicular to the optical axis of the second optical system, and the second surface is in a direction perpendicular to the ridgeline between the first surface and the second surface. Represents the average value of the face length of
_φL represents the luminous flux diameter of the second light beam on the plane perpendicular to the optical axis of the second optical system at the end position of the light guide member on the wavelength conversion element side. The light source optical system according to claim 2 or 3, wherein the first surface of the light guide member reflects the first light flux toward the wavelength conversion element. The light source according to any one of claims 1 to 4, wherein a part of the second light beam to be separated is totally reflected a plurality of times inside the light guide member and then emitted. Optical system. The light guide member has a parallel flat plate shape, and a part of the separated second light beam is incident on the first end face of the peripheral edge of the light guide member and emitted from the second end face. The light source optical system according to any one of claims 1 to 5. The light guide member is arranged at a position intersecting the optical axis of the second optical system, and a part of the second light beam is transferred from one region sandwiching the plane including the optical axis to the other region. The light source optical system according to any one of claims 1 to 6, wherein the light source is guided. The light source optical system according to any one of claims 1 to 6, wherein the light guide member brings a part of the second light beam closer to the optical axis of the second optical system. The light source optical system according to any one of claims 1 to 6, wherein the light guide member keeps a part of the second light beam away from the optical axis of the second optical system. 6. The light source optical system described. The angle between the normal of the second surface and the optical axis of the second optical system is
The light source optical system according to claim 2, wherein the angle is smaller than the angle formed by the normal of the first surface and the optical axis of the second optical system. A light source unit in which a first light flux emitted from a light source is incident on a wavelength conversion element by a first optical system, and a second light flux having been wavelength-converted by the wavelength conversion element is emitted through a second optical system.
A light source unit comprising, in the second optical system, a light guide member that separates a part of the second luminous flux in the second optical system. Light source and
A first optical system that causes the first luminous flux emitted from the light source to enter the wavelength conversion element, and
A second optical system through which the second luminous flux converted by the wavelength conversion element is transmitted, and
It is a light source device having
A light source device comprising, in the second optical system, a light guide member that separates a part of the second luminous flux in the second optical system. It includes a first optical system that forms an optical path through which a first light flux passes from a light source to a wavelength conversion element, and a second optical system that forms an optical path through which a second light flux converted by the wavelength conversion element passes. Light source device and
An image display element that modulates the light from the light source device to form an image, and
A projection optical system that projects the image onto the projected surface,
It is an image display device having
An image display device comprising the light guide member for separating a part of the second luminous flux in the second optical system in the second optical system.

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