JP2012181309A - Rotary wheel optical system and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To implement a light source where surface deflection of a fluorescent wheel is reduced, and a projector including a light source where surface deflection of a fluorescent wheel is reduced.SOLUTION: A rotary wheel optical system 700 includes a first member 51 in front of a rotary wheel 30 and includes a second member 52 at the rear of the rotary wheel 30, and the first member 51 and the second member 52 overlap with each other in plan view when the rotary wheel 30 is viewed from a direction parallel with a revolving shaft of the rotary wheel 30.

Description

  The present invention relates to a rotating wheel optical system and a projector.

  In the field of projectors, conventionally, a discharge lamp such as an ultra-high pressure mercury lamp has been mainly used as a light source. In contrast, in recent years, light emitting diodes (Light Emitting Diodes, hereinafter abbreviated as “LEDs”), light sources that emit light from a fluorescent material using light from a solid light source such as a laser as excitation light, and use the light have been proposed. (For example, refer to Patent Document 1).

The light source device of Patent Document 1 includes an excitation light source composed of an LED, a laser emitter, and the like, and a rotatable fluorescent wheel having three regions of a red phosphor forming region, a green phosphor forming region, and a diffusion layer forming region. I have. In this light source device, when the blue wavelength band light is emitted as excitation light from the excitation light source, and the excitation light is irradiated to the fluorescent wheel, the excitation light is irradiated to the red phosphor forming region at the same time as rotating the fluorescent wheel. During the period when red light fluoresces, green light fluoresces during the period when the excitation light is irradiated on the green phosphor formation region, and it is excitation light during the period when the excitation light is irradiated on the diffusion layer formation region Blue light is diffused and emitted.
According to Patent Document 1, it is described that visible light having lower energy than ultraviolet light is irradiated as excitation light, so that deterioration over time of optical components irradiated with excitation light can be suppressed and performance can be maintained over a long period of time. ing.

JP 2009-277516 A JP 2004-53692 A

In the light source device of Patent Document 1, even if the laser light applied to the phosphor is a laser light in the visible light region having lower energy than ultraviolet light, if the intensity of the laser light is high, conversion loss in the phosphor As a part of the heat is changed into heat, the phosphor wheel generates heat. On the other hand, the fluorescent wheel can be cooled to some extent by adopting a configuration in which light is irradiated from a laser emitter to a predetermined position of the fluorescent wheel while rotating the fluorescent wheel.
This is because the area of the fluorescent wheel is sufficiently large with respect to the irradiation area of the laser light, and the effect that heat is diffused, and the irradiation area is continuously changed by the rotation of the fluorescent wheel, and is irradiated per spot. This is because the effect of shortening the time and the effect of cooling the whole wheel by rotating the fluorescent wheel can be expected.
Here, if it is going to improve the output of a light source device, it is necessary to increase the irradiation amount of a laser beam further, In that case, the improvement of the further cooling performance is desired. Therefore, it is conceivable to increase the rotation speed of the fluorescent wheel. However, when the rotation speed of the fluorescent wheel increases, the surface shake of the fluorescent wheel tends to occur.
Here, “surface runout” is a phenomenon in which the rotating surface is tilted. For example, a state in which the rotating surface is perpendicular to the optical axis direction is an initial state, and a state where the rotating surface is out of a state perpendicular to the optical axis direction is referred to as “surface vibration”.

  Further, in the apparatus of Patent Document 2, a measure is taken such that a cooling fan is installed in the vicinity of the wheel, and cooling air from the cooling fan is blown onto the wheel to suppress an increase in the temperature of the wheel. However, when a duct is formed so as to cover one side, there is a problem that the shape becomes complicated in order not to block the optical path. In addition, there is a problem that the wheel may run out due to increase or decrease of the air volume.

  Such surface wobbling of the fluorescent wheel causes a shift of the light emission position in the optical axis direction and a fluctuation in the light distribution of light emission. As a result, light loss in the optical path increases and brightness decreases.

  Accordingly, the present invention has been made to solve at least a part of the above-described problems, and includes a rotating wheel optical system in which the surface shake of the fluorescent wheel is reduced, and a light source device in which the surface shake of the fluorescent wheel is reduced. For the purpose of realizing the projector, it can be realized as the following forms or application examples.

  The rotating wheel optical system according to the present invention is disposed on a first wheel side of the rotating wheel that is rotatable around a predetermined rotation axis, and guides a first coolant onto the first surface. A first member configured to be capable of being disposed on the second surface side of the rotating wheel, and configured to be capable of guiding a second cooling medium onto the second surface. A second member, and the first member and the second member at least partially overlap each other in plan view when the rotary wheel is viewed from a direction parallel to the rotation axis. It is characterized by.

  By arranging the first member on the first surface side of the rotating wheel, the first coolant capable of flowing the first cooling medium between the first member and the first surface of the rotating wheel is provided. A flow path is formed. Further, by arranging the second member on the second surface side of the rotating wheel, the second coolant can flow between the second member and the second surface of the rotating wheel. Two flow paths are formed. According to this, when the first cooling medium is caused to flow through the first flow path and the second cooling medium is caused to flow through the second flow path, a force is applied from both sides of the rotating wheel to reduce surface runout. Can do. The internal pressure applied to the flow path (pressure that pushes the wall in the flow path) is determined by the density of the cooling medium in the flow path. If there is no complicated structure such as a restriction in the flow path to avoid pressure loss, the density of the coolant inside the flow path is determined by the difference between the pressure at the supply port of the flow path and the pressure at the discharge port. Assuming that the area of the supply port, the area of the discharge port, the characteristics of the cooling medium supply means, and the characteristics of the cooling medium discharge destination are equal in the first and second flow paths, The internal pressure of the flow path is equal. Here, the supply means includes a fan, a pump, and the like, and the discharge destination includes an open air release and a coolant circulation pipe. Assuming that the internal pressures of the first and second flow paths are equal, the force applied to the rotating wheel is proportional to the area of the overlapping portion of the flow path and the rotating wheel. Therefore, by rotating the first member and the second member at least partially overlapping each other in a plan view, the rotating wheel rotates in the region sandwiched between the first member and the second member. The same level of force can be applied from both sides of the wheel, and a high surface runout reduction effect can be obtained.

  In the rotating wheel optical system described above, the rotating wheel is disposed at an intermediate position between the first member and the second member.

  Since the rotating wheel is disposed at an intermediate position between the first member and the second member, the distance between the first member and the rotating wheel is substantially equal to the distance between the second member and the rotating wheel. . The gap between the first member and the rotating wheel and the gap between the second member and the rotating wheel are considered to be part of the cooling medium discharge port because of leakage of the cooling medium. Therefore, since the distance between the first member and the rotating wheel is equal to the distance between the second member and the rotating wheel, it is easy to make the internal pressures of the first and second flow paths equal to each other. By making the internal pressures of the first and second flow paths equal to each other, the same force can be applied from both sides of the rotating wheel, and a high surface vibration reduction effect can be obtained. Furthermore, since the internal pressure (density of the cooling medium) of the first and second flow paths is the same, for example, the distance between the first member and the rotating wheel is reduced, and the distance between the second member and the rotating wheel is reduced. When the pressure spreads, the pressure in the first flow path increases and the pressure in the second flow path decreases, thereby generating a force for returning the rotating wheel to the original state. Therefore, by arranging the rotating wheel at an intermediate position between the first member and the second member, not only can the size of the surface runout be reduced, but the shaked surface can be returned to the original position.

  In the rotating wheel optical system described above, the predetermined light irradiation region irradiated with light when the rotating wheel is rotating is such that the first member and the second member are rotated in plan view. It can be provided in a region different from the region overlapping the wheel.

  By preventing the first member from overlapping the light irradiation region, a material that is not colorless and transparent can be selected as the material of the first member. For example, plastics that are low in cost and excellent in workability, and materials such as resins are often colored, and colored ones are relatively cheaper than transparent ones. Furthermore, the material present on the optical path requires not only transparency but also refractive index uniformity and surface accuracy. Similarly, a material that is not colorless and transparent can be selected as the material of the second member.

  In the rotating wheel optical system described above, on the circumference including the center of the light irradiation region and centering on the rotation axis, the center of the light irradiation region is a starting point, and the first member is a flat surface. When the center of the region overlapping with the wheel is regarded as the end point, the rotation angle of the wheel can be 180 degrees or less.

  When the angle of rotation from the light irradiation region is 180 degrees or less, that is, within a half circumference, cooling can be started immediately after heat generation (light irradiation). In the forced cooling, the cooling effect increases as the temperature difference between the cooling medium and the heat generating portion increases. Therefore, high cooling efficiency can be realized by starting cooling immediately after heat generation.

  In the rotating wheel optical system described above, the first member and the second member can be provided so as to avoid the rotating shaft.

  When the first member is provided in the radial direction of the rotating wheel without avoiding the rotating shaft of the rotating wheel, the rotating shaft becomes an obstacle, so it is difficult to increase the distance of the first flow path, and pressure loss is also caused. There is a drawback that becomes larger. On the other hand, by providing the first member so as to avoid the rotating shaft, it is easy to lengthen the first flow path and there is no pressure loss due to a failure, so that high cooling efficiency can be realized. The same can be said for the second member.

  The rotary wheel optical system described above further includes a cooling medium supply unit that supplies the first cooling medium and the second cooling medium, and is formed between the first member and the first surface. The internal pressure of the first flow path and the internal pressure of the second flow path formed between the second member and the second surface can be made equal to each other.

  By making the internal pressure of the first flow path and the internal pressure of the second flow path equal to each other, the region where the rotary wheel is sandwiched between the first member and the second member can be mutually connected from both sides of the rotary wheel. The same level of force can be applied. Therefore, the surface shake reduction effect can be enhanced.

  In the projector according to the aspect of the invention, the rotating wheel optical system described above, a light source disposed in front of the rotating wheel optical system, a light modulation element that modulates light that has passed through the rotating wheel optical system, and the light modulation A projection optical system that projects light modulated by the element onto a projection surface.

  By using the rotating wheel optical system of the present invention, a bright and long-life projector can be realized.

It is a schematic block diagram of the projector of one Embodiment of this invention. It is the schematic which shows the example of the phosphor wheel used for this projector, (A) is the top view which looked at the phosphor wheel from the direction parallel to the rotating shaft, (B) is the side view of a phosphor wheel is there. It is the schematic which shows the example of the rotation wheel optical system used for this projector, (A) is the top view which looked at the rotation wheel optical system from the direction parallel to the rotating shaft of a fluorescent substance wheel, (B) is FIG. It is BB 'sectional drawing of (A). It is the schematic which shows the example of the rotation wheel optical system used for this projector, (A) is the top view which looked at the rotation wheel optical system from the direction parallel to the rotating shaft of a fluorescent substance wheel, (B) is FIG. It is CC 'sectional drawing of (A).

[First Embodiment]
Hereinafter, a rotating wheel optical system 700 and a projector PJ according to a first embodiment of the present invention will be described with reference to the drawings. In all the drawings below, dimensions and ratios are appropriately changed depending on the components in order to make each component easy to see.

FIG. 1 is a schematic configuration diagram illustrating a light source device 100 and a projector PJ according to the present embodiment.
As shown in FIG. 1, the projector PJ includes a light source device 100, a color separation optical system 200, a liquid crystal light valve (light modulation element) 400R, a liquid crystal light valve 400G, a liquid crystal light valve 400B, a dichroic prism (color combining element) 500, A projection optical system 600 is included.

  The projector PJ generally operates as follows. The light emitted from the light source device 100 is separated into a plurality of color lights of different colors by the color separation optical system 200. The plurality of color lights separated by the color separation optical system 200 are incident on the corresponding liquid crystal light valve 400R, liquid crystal light valve 400G, and liquid crystal light valve 400B and modulated. The plurality of color lights modulated by the liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B enter the dichroic prism 500 and are combined. The light synthesized by the dichroic prism 500 is enlarged and projected onto the projection surface of the screen SCR by the projection optical system 600, and a full-color projection image is displayed.

Hereinafter, each component of the projector PJ will be described.
The light source device 100 includes a laser light source 10 (a solid light source for excitation light), a condensing lens 22, a rotating wheel optical system 700, a collimating optical system 60, a lens array 120, a lens array 130, a polarization conversion element 140, and a superimposing lens 150. They are arranged in order.

  The rotating wheel optical system 700 includes a phosphor wheel (rotating wheel) 30, a motor 50, a first member 51, and a second member 52.

  The laser light source 10 is a blue laser light source that emits blue laser light having an emission intensity peak of, for example, 445 nm as excitation light that excites a phosphor layer provided in the phosphor wheel 30 described later. Here, a single laser light source is provided as the laser light source 10, but a plurality of laser light sources may be provided. Further, it may be a laser light source that emits colored light having a peak wavelength other than 445 nm as long as it is light having a wavelength that can excite a phosphor layer to be described later.

  The condenser lens 22 is a convex lens. When a plurality of laser light sources 10 are provided, one condensing lens is arranged corresponding to each laser light source 10, and one convex lens common to all the laser light sources is arranged at the subsequent stage. good. The condensing lens 22 is disposed on the optical axis of the laser light emitted from the laser light source 10 and condenses the excitation light emitted from the laser light source 10.

  The phosphor wheel 30 transmits a part of the excitation light (blue laser light) emitted from the laser light source 10, and the remaining part is absorbed by the phosphor, so that the peak of the emission intensity becomes yellow fluorescence of, for example, about 550 nm. It has a function to convert. Accordingly, white light is emitted from the phosphor wheel 30 as a result of combining a part of the blue light that is the excitation light and the yellow light emitted from the phosphor.

FIG. 2 is a schematic view showing the phosphor wheel 30 of the present embodiment. 2A is a plan view of the phosphor wheel 30 viewed from a direction parallel to the rotation axis thereof, and FIG. 2B is a side view of the phosphor wheel 30. FIG.
As illustrated in FIG. 2, the phosphor wheel 30 includes a base body 40 having a circular planar shape and a phosphor layer 42 provided on the base body 40 along the circumferential direction. The phosphor wheel 30 is arranged such that, of the two main surfaces of the base body 40, the first surface 40 a on the side where the phosphor layer 42 is formed faces the condenser lens 22, and the condenser lens The focal position of the excitation light condensed by 22 is arranged so as to coincide with the position of the phosphor layer 42. For example, the diameter of the circular phosphor wheel 30 is 50 mm, and the phosphor wheel 30 is provided so that the excitation light is incident at a position about 22.5 mm away from the center of the phosphor wheel 30 in plan view. Then, the fluorescence emitted from the phosphor layer 42 is emitted from the second surface 40 b on the side where the phosphor layer 42 is not formed, of the two main surfaces of the base body 40. In the present specification, the first surface 40 a of the base body 40 is referred to as the first surface 40 a of the phosphor wheel 30, and the second surface 40 b of the base body 40 is referred to as the second surface 40 b of the phosphor wheel 30.

  As shown in FIG. 2, a motor 50 is connected to the center of the base body 40 via a shaft 44. Therefore, the phosphor wheel 30 can rotate with the normal line passing through the center of the shaft 44, that is, the center of the phosphor wheel 30 as the rotation axis. The motor 50 rotates the phosphor wheel 30 at, for example, 7500 rpm. In this case, the irradiation area (beam spot) of the excitation light on the phosphor wheel 30 moves at about 18 m / second. That is, the motor 50 functions as a position displacement unit that displaces the position of the beam spot on the phosphor wheel 30. Thereby, since excitation light does not continue irradiating the same position on the fluorescent substance wheel 30, the thermal deterioration of an irradiation area | region can be prevented and a rotating optical wheel system can be lengthened. The functions of the first member 51 and the second member 52 will be described later as an explanation of the rotating wheel optical system 700.

As described above, the phosphor layer 42 transmits part of the excitation light (blue laser light) emitted from the laser light source 10 and absorbs the remaining part to absorb yellow (emission intensity peak: about 550 nm). Is emitted. The light emitted from the phosphor layer 42 forms white light by mixing a part of blue excitation light and yellow fluorescence.
Further, the phosphor layer 42 includes a light-transmitting base material, a plurality of phosphor particles that emit fluorescence, and a plurality of filler particles that are particulate substances having light transmittance. The base material contains a plurality of phosphor particles and a plurality of filler particles. As the material for forming the base material, a resin material having optical transparency can be used. For example, a silicone resin having a high heat resistance (refractive index: about 1.4) can be suitably used.

The phosphor particles are particulate fluorescent materials that absorb excitation light emitted from the laser light source 10 shown in FIG. 1 and emit fluorescence. For example, the phosphor particles include a substance that emits fluorescence when excited by blue laser light having a wavelength of about 445 nm, and a part of the excitation light emitted by the laser light source 10 is changed from the red wavelength band to the green color. It is converted into light including the wavelength band, that is, converted into yellow light and emitted.
As such phosphor particles, those having an average particle diameter of about 1 μm to several tens of μm are known to exhibit high luminous efficiency. As the phosphor particles, known YAG (yttrium / aluminum / garnet) phosphors can be used. For example, a YAG phosphor (refractive index: about 1.8) having an average particle size of 10 μm and a composition represented by (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce can be used. In addition, the constituent material of the phosphor particles may be one kind, or a mixture of particles made of two or more kinds of constituent materials may be used as the phosphor particles.

The filler particles have a function of diffusing excitation light incident on the phosphor layer 42 and fluorescence emitted from the phosphor particles. As a constituent material of the filler particles, a wide variety of materials such as a resin material and an inorganic material can be used as long as they are particulate substances having light transmittance. Among them, an inorganic material having high heat resistance can be suitably used. For example, Al ₂ O ₃ (refractive index: about 1.8) having an average particle diameter of 10 μm can be used.

  As shown in FIG. 1, the collimating optical system 60 includes a first lens 62 that suppresses the spread of light from the phosphor wheel 30 and a second lens 64 that substantially collimates the light incident from the first lens 62. The light emitted from the phosphor wheel 30 as a whole is made parallel. The first lens 62 and the second lens 64 are configured as convex lenses.

The lens array 120 and the lens array 130 make the luminance distribution of the light emitted from the collimating optical system 60 uniform. The lens array 120 includes a plurality of first microlenses 122, and the lens array 130 includes a plurality of second microlenses 132. The first microlens 122 has a one-to-one correspondence with the second microlens 132.
The light emitted from the collimating optical system 60 is spatially divided and incident on the plurality of first microlenses 122. The first micro lens 122 forms an image of the incident light on the corresponding second micro lens 132. Thereby, a secondary light source image is formed on each of the plurality of second microlenses 132. Note that the outer shapes of the first microlens 122 and the second microlens 132 are substantially similar to the outer shapes of the image forming regions of the liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B.

The polarization conversion element 140 aligns the polarization state of the light L emitted from the lens array 120 and the lens array 130. The polarization conversion element 140 receives the light L from the phosphor wheel 30 and is a polarization separation element that separates two lights having different polarization directions included in the incident light L, for example, P polarization and S polarization, A retardation plate that converts the polarization direction of one of the two lights having different polarization directions into the polarization direction of the other light. Further, the polarization separation element has a polarization separation film (hereinafter referred to as a PBS film) and a mirror according to the incident position of the light L from each second microlens 132 of the lens array 130.
The light L incident on each incident region is separated into P-polarized light (P-polarized light with respect to the PBS film) and S-polarized light (P-polarized light with respect to the PBS film) by the PBS film. One of the P-polarized light and S-polarized light (for example, S-polarized light) is reflected by the mirror and then enters the phase difference plate. The S-polarized light incident on the retardation plate is converted into the polarization state of the other polarized light (here, P-polarized light) by the retardation plate, and converted into one of the P-polarized light and S-polarized light (here, P-polarized light). Become and is injected.

  The superimposing lens 150 superimposes the light emitted from the polarization conversion element 140 on the liquid crystal light valves (illuminated areas) 400R, 400G, and 400B. The light emitted from the light source device 100 is spatially divided and then superimposed, whereby the luminance distribution is made uniform and the axial symmetry around the light axis 100ax is enhanced.

The color separation optical system 200 includes a dichroic mirror 210, a dichroic mirror 220, a mirror 230, a mirror 240, a mirror 250, a relay lens 260, and a relay lens 270.
The dichroic mirror 210 and the dichroic mirror 220 are obtained by, for example, laminating a dielectric multilayer film on a glass surface. The dichroic mirror 210 and the dichroic mirror 220 have a characteristic of selectively reflecting color light in a predetermined wavelength band and transmitting color light in other wavelength bands. Here, the dichroic mirror 210 has a characteristic of reflecting green light and blue light and transmitting red light. The dichroic mirror 220 has a characteristic of reflecting green light and transmitting blue light among green light and blue light transmitted through the dichroic mirror 210.

  The light L emitted from the light source device 100 enters the dichroic mirror 210. The red light R of the light L enters the mirror 230 through the dichroic mirror 210, is reflected by the mirror 230, and enters the field lens 300R. The red light R is collimated by the field lens 300R and then enters the liquid crystal light valve 400R for red light modulation.

  Green light G and blue light B in the light L are reflected by the dichroic mirror 210 and enter the dichroic mirror 220. The green light G is reflected by the dichroic mirror 220 and enters the field lens 300G. The green light G is collimated by the field lens 300G and then enters the liquid crystal light valve 400G for green light modulation.

  On the other hand, the blue light B that has passed through the dichroic mirror 220 passes through the relay lens 260 and is reflected by the mirror 240, then passes through the relay lens 270, is reflected by the mirror 250, and enters the field lens 300B. The blue light B is collimated by the field lens 300B and then enters the liquid crystal light valve 400B for blue light modulation.

The liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B are configured by a light modulation device such as a transmissive liquid crystal light valve. The liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B are electrically connected to a signal source (not shown) such as a personal computer that supplies an image signal including image information.
The liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B modulate the incident light for each pixel based on the supplied image signal to form an image. The liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B form a red image, a green image, and a blue image, respectively. The light (formed image) modulated by the liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B enters the dichroic prism 500.

The dichroic prism 500 has a structure in which four triangular prisms are bonded to each other. The surface to be bonded in the triangular prism is the inner surface of the dichroic prism 500. On the inner surface of the dichroic prism 500, a mirror surface that reflects red light and transmits green light and a mirror surface that reflects blue light and transmits green light are formed orthogonal to each other.
The green light incident on the dichroic prism 500 is emitted as it is through the mirror surface. The red light and blue light incident on the dichroic prism 500 are selectively reflected or transmitted by the mirror surface and emitted in the same direction as the emission direction of the green light. In this way, the three color lights (images) are superimposed and synthesized, and the synthesized color lights are enlarged and projected onto the screen SCR by the projection optical system 600.

FIG. 3 is a schematic diagram showing a rotating wheel optical system 700 of the present embodiment. 3A is a plan view of the rotating wheel optical system 700 viewed from a direction parallel to the rotation axis of the phosphor wheel 30, and FIG. 3B is a cross-sectional view taken along the line BB ′ of FIG. FIG.
As shown in FIG. 3, the rotating wheel optical system 700 includes a phosphor wheel 30 (rotating wheel), a motor 50, a first member 51, a second member 52, and a fan 53. The first member 51 is provided on the first surface 40 a side of the phosphor wheel 30, and the second member 52 is provided on the second surface 40 b side of the phosphor wheel 30. The optical configuration of the phosphor wheel 30 and the principle of light emission are as described above. In addition, as described above, the phosphor wheel 30 can be rotated around the rotation axis in order to prevent thermal deterioration of the light irradiation region A described later.

  In FIG. 3A, the region indicated by the symbol A is a light irradiation region in which the phosphor wheel 30 is irradiated with excitation light. Although the relative positional relationship between the light irradiation region A and the first member 51 and the relative positional relationship between the light irradiation region A and the second member 52 are fixed, the phosphor wheel 30 has a rotational axis. Actually, the light irradiation area A on the phosphor wheel 30 moves around the rotation axis because it rotates around.

  Here, functions of the first member 51 and the second member 52 will be described. As shown in FIG. 3B, the cross section of the first member 51 is not cylindrical, but has a shape opened toward the first surface 40a of the phosphor wheel 30. 3B has a rectangular shape, it may have, for example, a U-shaped cross-sectional shape. As a result, a first flow path X through which the first cooling medium is guided is formed between the first member 51 and the first surface 40 a of the phosphor wheel 30. The cross section of the second member 52 is not cylindrical, but has a shape that opens toward the second surface 40b of the phosphor wheel 30. As a result, a second flow path Y through which the second cooling medium is guided is formed between the second member 52 and the second surface 40b of the phosphor wheel 30.

As shown in FIG. 3A, the first cooling medium supplied from the fan 53, which is an example of the cooling medium supply means, flows on the first surface 40a along the first flow path X. The phosphor wheel 30 is cooled. Further, the second cooling medium supplied from the fan 53 flows on the second surface 40b along the second flow path Y, thereby cooling the phosphor wheel 30. In the present embodiment, air is used as the cooling medium.
When the phosphor wheel 30 is viewed from a direction parallel to the rotation axis, the first member 51 and the second member 52 overlap each other in plan view. Further, as shown in FIG. 3B, the phosphor wheel 30 is disposed at an intermediate position between the first member 51 and the second member 52 in a state where the phosphor wheel 30 is not rotating. Yes.
That is, the cross-sectional area of the first flow path X (cooling path) formed between the first surface 40a of the phosphor wheel 30 and the first member 51 when the phosphor wheel 30 is not rotating. Is equal to the cross-sectional area of the second flow path Y (cooling path) formed between the second surface 40b of the phosphor wheel 30 and the second member 52. A second member 52 is configured. In addition, by distributing the coolant supplied from one fan 53 to the first coolant and the second coolant, the flow rate of the first coolant supplied to the first flow path X is the first. The flow rate of the first cooling medium supplied to the first flow path X is equal to the flow rate of the second cooling medium supplied to the second flow path Y, and the second flow rate supplied to the second flow path Y is the second flow rate. It is equal to the flow rate of the cooling medium. That is, the internal pressure of the first flow path is equal to the internal pressure of the second flow path. The first member 51 and the second member 52 are arranged at 90 degrees which is within a half circumference (180 degrees) from the light irradiation region A. The first member 51 is arranged so that the first cooling medium flows in the circumferential direction of the phosphor wheel 30, and the second member 52 is arranged so that the second cooling medium flows in the circumferential direction of the phosphor wheel 30. Has been placed. That is, the direction in which the first cooling medium flows and the direction in which the second cooling medium flows match the rotation direction of the phosphor wheel 30.

In the phosphor wheel 30 according to the present embodiment, the first member 51 and the second member 52 overlap each other in plan view when the phosphor wheel 30 is viewed from a direction parallel to the rotation axis. . A force corresponding to the internal pressure of the first flow path X is applied to the phosphor wheel 30 from the first member 51 side, and a force corresponding to the internal pressure of the second flow path Y is applied to the phosphor wheel 30 on the second member 52. Take from the side.
In this way, the first cooling medium is caused to flow through the first flow path X, and the second cooling medium is caused to flow through the second flow path Y, whereby the phosphor wheel 30 and the second member 51 are moved to the second flow path Y. A force can be applied to the region sandwiched between the members 52 from both sides of the phosphor wheel 30. For this reason, the surface shake of the phosphor wheel 30 can be reduced.

  The force applied to the phosphor wheel 30 from the first member 51 side is proportional to the area where the phosphor wheel 30 and the first member 51 overlap each other, and the phosphor wheel 30 is applied to the phosphor wheel 30 from the second member 52 side. The force is proportional to the area where the phosphor wheel 30 and the second member 52 overlap each other. Therefore, if the internal pressure of the first flow path X is made equal to the internal pressure of the second flow path Y, the phosphor wheel 30 is fluorescent in the region sandwiched between the first member 51 and the second member 52. The same level of force can be applied from both sides of the body wheel 30. Therefore, it is possible to realize further reduction in surface vibration.

  Further, in the phosphor wheel 30 according to the present embodiment, the phosphor wheel 30 is disposed at an intermediate position between the first member 51 and the second member 52, so that the first member 51 and the phosphor wheel 30 The distance between the first surface 40a and the distance between the second member 52 and the second surface 40b of the phosphor wheel 30 are substantially equal. That is, the first member 51 and the second member are set so that the cross-sectional area of the first flow path X is equal to the cross-sectional area of the second flow path Y when the phosphor wheel 30 is not rotating. 52.

A first cooling medium and a second cooling medium having the same flow rate (amount of cooling medium flowing per unit time) are respectively supplied to the first flow path X and the second flow path Y having the same cross section. By supplying, it is possible to apply the same force to the first surface 40a and the second surface 40b of the phosphor wheel 30, and it is possible to reduce surface vibration. Furthermore, for example, when the distance between the first member 51 and the rotating wheel 30 is reduced and the distance between the second member 52 and the rotating wheel 30 is increased, the flow rate per channel area in the first channel X increases. As a result, the pressure rises, the flow rate per channel area in the second channel Y decreases, and the pressure decreases, thereby generating a force for returning the rotating wheel to the original state.
Therefore, by arranging the phosphor wheel 30 at an intermediate position between the first member 51 and the second member 52, not only the surface shake is reduced, but also the surface that is shaken when the surface shake occurs is returned to the original position. It is also possible to obtain a surface shake correction effect that returns to

Further, in the phosphor wheel 30 according to the present embodiment, the light irradiation region A to which light is irradiated when the phosphor wheel 30 is rotated is the first member 51 and the second member 52 in plan view. It is provided in a region different from the region overlapping with the phosphor wheel 30.
By preventing the first member 51 from overlapping the light irradiation region A, a material that is not colorless and transparent can be selected as the material of the first member 51. For example, plastics that are low in cost and excellent in workability, and materials such as resins are often colored, and colored ones are relatively cheaper than transparent ones. Furthermore, it is not necessary to consider refractive index uniformity and surface accuracy, and the cost can be reduced. Similarly, by preventing the second member 52 from overlapping the light irradiation region A, a material that is not colorless and transparent can be selected as the material of the second member.

Further, in the phosphor wheel 30 according to the present embodiment, the center of the light irradiation region A is set as the starting point on the circumference including the center of the light irradiation region A and the rotation axis of the phosphor wheel 30 as the center. When the center of a region where one member 51 overlaps the phosphor wheel 30 in plan view is the end point, the rotation angle of the phosphor wheel 30 is set to 90 degrees.
When the rotation angle from the light irradiation region A is 90 degrees or less, cooling can be started immediately after heat generation (light irradiation). In the forced cooling, the cooling effect increases as the temperature difference between the cooling medium and the heat generating portion increases. Therefore, high cooling efficiency can be realized by starting cooling immediately after heat generation. Conversely, when the light irradiation region A is separated from the first member 51 and the second member 52, the arrangement of the first member 51 and the arrangement of the second member 52 are facilitated. The restriction on the shape of the member 51 and the restriction on the shape of the second member 52 are reduced. In the present embodiment, the angle of rotation from the light irradiation region A is set to 90 degrees in consideration of the size of the cooling effect and the ease of arrangement. Considering only the cooling effect, by setting the rotation angle to 180 degrees or less (within half a circle), the temperature of the heat generating part is higher than when the rotation angle is larger than 180 degrees, so that the cooling efficiency can be increased.

  Further, in the phosphor wheel 30 according to the present embodiment, the first flow path X formed between the first surface 40 a of the phosphor wheel 30 and the first member 51 is the rotation axis of the phosphor wheel 30. Do not cross with. More specifically, the first member 51 is provided so as to avoid the shaft 44 of the motor 50. When the first member 51 is provided in the radial direction of the phosphor wheel 30, the rotation axis becomes an obstacle, so that the first channel X (cooling channel) is difficult to lengthen and the pressure loss increases. is there. On the other hand, by providing the first member 51 so as to avoid the shaft 44 of the motor 50, it is easy to lengthen the first flow path X (cooling path), and there is no pressure loss due to a failure. Can be increased. By arranging the second member 52 in the same form as the first member 51, the cooling efficiency can be further increased.

  Further, in the phosphor wheel 30 according to the present embodiment, the direction in which the cooling medium flows coincides with the rotation direction of the phosphor wheel 30. The temperature of the cooling medium rises during the cooling process. By matching the direction in which the coolant flows and the direction of rotation of the phosphor wheel 30, forced cooling (air cooling) can be started from a state in which the coolant is at the lowest temperature and the heat generating portion is at the highest temperature. The greater the temperature difference between the temperature of the cooling medium and the heat generating part, the greater the cooling effect, and thus the cooling efficiency can be further increased.

Further, in the phosphor wheel 30 according to the present embodiment, it is assumed that the flow rate of the cooling medium is high. However, when the flow rate of the cooling medium is low, the cooling medium is caused to flow in the direction opposite to the rotation direction of the phosphor wheel 30. Thus, the relative flow rate with respect to the phosphor wheel 30 can be increased.
Thereby, when the flow rate of the cooling medium is slow, the cooling efficiency can be greatly improved by increasing the relative flow rate. When the flow rate of the cooling medium is high, the effect of the increase in the flow rate on the cooling efficiency is reduced. Therefore, as described in this embodiment, it is better to match the rotation direction of the phosphor wheel 30 and the direction of the cooling medium. preferable.

[Second Embodiment]
FIG. 4 is a schematic diagram illustrating a rotating wheel optical system 800 according to the second embodiment. 4A is a plan view of the rotating wheel optical system 800 as viewed from a direction parallel to the rotation axis of the phosphor wheel 30, and FIG. 4B is a cross-sectional view taken along the line CC ′ of FIG. It is.
The rotating wheel optical system 800 is different from the rotating wheel optical system 700 of the first embodiment in the shape of the first member and the shape of the second member. As shown in FIG. 4, each of the first member 54 and the second member 55 has a portion curved in an arc shape in plan view, and is provided around the rotation axis.

The first cooling medium supplied from the fan 53 which is an example of the cooling air supply means flows on the first surface 40a along the first flow path X, thereby cooling the phosphor wheel 30. Further, the second cooling medium supplied from the fan 53 flows on the second surface 40b along the second flow path Y, thereby cooling the phosphor wheel 30. In the present embodiment, air is used as the cooling medium.
When the phosphor wheel 30 is viewed from a direction parallel to the rotation axis, the first member 54 and the second member 55 overlap with each other in a plan view, and further, as shown in FIG. The wheel 30 is disposed at an intermediate position between the first member 54 and the second member 55.
Further, each of the first member 54 and the second member 55 has an arc shape in accordance with the shape of the phosphor wheel 30 and is provided so as to avoid the shaft 44 of the motor 50. By making the first member 54 arc-shaped, the first flow path X formed by the first surface 40a of the phosphor wheel 30 and the first member 54 can be lengthened. Moreover, the 2nd flow path formed with the 2nd surface 40b of the fluorescent substance wheel 30 and the 2nd member 55 can be lengthened by making the 2nd member 55 into circular arc shape. Therefore, compared with the rotating wheel optical system 700 of the first embodiment, it is possible to increase the area of the region where the force is applied to the phosphor wheel 30. Therefore, it is possible to further enhance the surface shake reduction effect, the surface shake correction effect, and the cooling effect. Moreover, since the 1st flow path and the 2nd flow path do not bend at an acute angle, pressure loss can be reduced.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, as the phosphor wheel 30, the example in which the phosphor layer 42 is formed on the substrate 40 has been shown, but the phosphor may be dispersed in the substrate 40. Further, the shape of the phosphor wheel (rotating wheel) 30 is not limited to a circle, and a quadrangle or a polygon may be used. Even when a polygon is used as the rotating wheel 30, if the laser irradiation area is inside the rotating wheel 30, the locus of the laser irradiation spot is a circle. Therefore, even when a polygon is used as the rotating wheel 30, the locus of the laser irradiation spot is circular.

The base body 40 may be configured by combining a plurality of parts (for example, fan-shaped parts). A plurality of phosphor layers 42 may be provided on the substrate 40. For example, a plurality of regions are set on one substrate 40, a phosphor type, a phosphor layer thickness, and the presence or absence of a phosphor layer are selected for each region, and a rotating wheel whose emission color changes in a time-sharing manner is selected. It can also be manufactured.
Even when the base 40 is composed of a plurality of parts (for example, a fan shape), the type of phosphor, the thickness of the phosphor layer, and the presence or absence of the phosphor layer are selected for each part, and the rotating wheel whose emission color changes in a time-sharing manner. Can also be manufactured.

  Moreover, about the combination of the wavelength range of the light inject | emitted from a light source, and fluorescent substance material, it can change suitably. The shape of the first member, the shape of the second member, the arrangement of the first member, the arrangement of the second member, the cooling air supply means, the flow rate, and the flow rate can be changed as appropriate.

  Further, the phosphor wheel 30 may be housed in a sealed container, and a liquid may be used as a cooling medium.

  In the first embodiment and the second embodiment described above, the example in which the first member and the second member are completely overlapped with each other in plan view is shown, but this is not essential.

  The specific configuration, arrangement, shape, number, and the like of each optical element of the projector PJ are not limited to the above embodiment, and can be changed as appropriate. For example, the rotating wheel is not necessarily the phosphor wheel 30 and may be a color separation element that separates light of a white light source in a time division manner. The color separation element is, for example, a color wheel manufactured by combining a dichroic mirror.

  DESCRIPTION OF SYMBOLS 10 ... Laser light source (excitation light source), 30 ... Phosphor wheel (rotating wheel), 44 ... Shaft (rotating shaft), 50 ... Motor, 51 ... First member, 52 ... Second member, 54 ... First 1 member 55 55 second member 100 light source device 140 polarization conversion element 400R, 400G, 400B liquid crystal light valve (light modulation element) 600 projection optical system 700, 800 rotating wheel optics System, PJ ... Projector.

Claims (7)

A rotating wheel rotatable around a predetermined rotation axis;
A first member disposed on the first surface side of the rotating wheel and configured to be able to guide the first cooling medium onto the first surface;
A second member disposed on the second surface side of the rotating wheel and configured to be able to guide a second cooling medium onto the second surface;
When the rotary wheel is viewed from a direction parallel to the rotation axis, the first member and the second member at least partially overlap each other in plan view.   The rotating wheel optical system according to claim 1, wherein the rotating wheel is disposed at an intermediate position between the first member and the second member.   A predetermined light irradiation region irradiated with light when the rotating wheel is rotating is provided in a region different from a region where the first member and the second member overlap the rotating wheel in plan view. The rotating wheel optical system according to claim 1, wherein the rotating wheel optical system is provided. On the circumference including the center of the light irradiation region and centering on the rotation axis,
The center of the light irradiation area as a starting point,
When the center of the region where the first member overlaps the wheel in plan view is the end point,
The rotating wheel optical system according to any one of claims 1 to 3, wherein an angle of rotation of the wheel is 180 degrees or less.   5. The rotating wheel optical system according to claim 1, wherein the first member and the second member are provided so as to avoid the rotation shaft. 6. A cooling medium supply means for supplying the first cooling medium and the second cooling medium;
An internal pressure of a first flow path formed between the first member and the first surface, and a second flow path formed between the second member and the second surface. 6. The rotating wheel optical system according to claim 1, wherein the internal pressure is equal to each other. A rotating wheel optical system according to any one of claims 1 to 6;
A light source disposed in front of the rotating wheel optical system;
A light modulation element that modulates light that has passed through the rotating wheel optical system;
A projection optical system that projects the light modulated by the light modulation element onto the projection surface;
A projector characterized by comprising:

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