CN107748477B

CN107748477B - Light source device and projection display device

Info

Publication number: CN107748477B
Application number: CN201711143549.6A
Authority: CN
Inventors: 山影明广; 梅雨非
Original assignee: Light Show Technology Co Ltd
Current assignee: Sonoc Beijing Technology Co ltd
Priority date: 2017-06-13
Filing date: 2017-11-17
Publication date: 2020-08-11
Anticipated expiration: 2037-11-17
Also published as: CN107748477A; JP2019003760A

Abstract

The present invention relates to a light source device and a projection display device. In a conventional light source used for a projection display device, a rotating body coated with a phosphor is used, but a plate-shaped heat sink is provided on the rotating body to cool the rotating body in order to prevent the phosphor from overheating. When the plate-shaped heat sink is used, not only noise due to wind shear noise is increased, but also the manufacturing is not easy, so that the cost is easily increased. In contrast, in the light source device of the present invention, a spiral uneven structure is provided on the side surface of the cylindrical portion (102a) of the rotating body (102), and when the rotating body rotates during light emission, an AIR flow (AIR) is generated by the spiral uneven structure to cool the fluorescent material (103). Further, since the plate-shaped heat sink is easier to manufacture than a plate-shaped heat sink, it can be manufactured at low cost.

Description

Light source device and projection display device

Technical Field

The present invention relates to a light source device including a rotating body coated with a phosphor and a projection display device using the light source device.

Background

In recent years, semiconductor lasers have been developed which output light having a short wavelength with high emission efficiency. It has been proposed to use light obtained by exciting a phosphor with output light of such a semiconductor laser and converting the wavelength of the excited light as a light source of a projection display device.

Although the phosphor can be fixed at a certain position and irradiated with excitation light, if the excitation light is always continuously irradiated to the same point of the phosphor, the temperature may be locally increased, the light emission efficiency may be decreased, and further, the material may be deteriorated. Therefore, a light source is often used in which a fluorescent material is provided on the main surface of a rotating disk in advance so that excitation light does not irradiate the fluorescent material at the same point.

For example, patent document 1 describes a light source configured to irradiate a rotating fluorescent plate with output light of an excitation light source so as not to concentrate heat at one point of the fluorescent plate.

In the case where a light source with higher luminance is required, it is attempted to provide a structure for actively dissipating heat so as to suppress deterioration of the phosphor, instead of merely rotating the phosphor plate to prevent concentrated heat storage.

For example, patent document 2 describes a light source in which a heat radiation fin for heat radiation is provided on a color wheel provided with a fluorescent material.

Patent document 1: japanese patent laid-open publication No. 2012-78488

Patent document 2: japanese laid-open patent publication No. 2012-13897

In the light source described in patent document 2, since the plate-shaped

heat radiating fins

4b and 4c are provided as shown in fig. 7 (a), (b), and (c), air is diffused by centrifugal force when the color wheel rotates, and a cooling effect can be obtained.

However, as described in paragraph [0021] of patent document 2, when such a plate-shaped heat sink is used, there is a problem that noise due to wind shear sound becomes large. Muting is highly desired for projection display devices, both for home use and for business use, and the generation of noise due to wind whispering has become a problem.

Further, the plate-shaped fin structure shown in fig. 7 (a), (b), and (c) is not easy to manufacture. If the shape accuracy of the fins is low, not only the wind shear noise becomes large, but also vibration occurs during rotation due to imbalance in weight, and it is not easy to provide plate-shaped fin portions with high accuracy, and the manufacturing cost tends to increase.

Further, since the plate-like portion of the heat sink is easily deformed by an external force, there is a possibility that the plate-like portion is accidentally deformed when contacting the heat sink when the component is carried or when the projection display device is assembled, and therefore, it is necessary to pay close attention to handling.

Therefore, a light source which is suitable for achieving a cooling effect and can suppress noise caused by wind shear sound, and which is easy to manufacture and operate is desired.

Disclosure of Invention

The present invention is a light source device for a projection display device, comprising: a rotating body made of metal; a phosphor coated on the rotating body; and an excitation light source that outputs excitation light for exciting the phosphor, wherein the rotating body has a concave-convex structure extending in a spiral shape along a side surface thereof, and a rotation direction of the rotating body is a direction in which an air flow induced by the concave-convex structure extending in the spiral shape flows in a direction of the phosphor.

Further, the present invention is a projection display device including: the light source device described above; a light modulation device; and a projection lens.

According to the present invention, it is possible to provide a light source which is suitable for achieving a cooling effect and can suppress noise caused by wind shear, and which is easy to manufacture and operate. Also, a projection display device having such a light source device and having low noise and high luminance can be provided.

Drawings

Fig. 1 (a) is a sectional view of the rotating body of the first embodiment, and fig. 1 (b) is a front view of the rotating body of the first embodiment.

Fig. 2 is a configuration diagram of a projection display device including a light source device according to a first embodiment.

Fig. 3 (a) is a cross-sectional view of the rotating body of the second embodiment, fig. 3 (b) is a front view of the rotating body of the second embodiment, and fig. 3 (c) is an external view of the rotating body of the second embodiment.

Fig. 4 (a) is a sectional view of the rotating body of the third embodiment, and fig. 4 (b) is a front view of the rotating body of the third embodiment.

Fig. 5 (a) is a sectional view of the rotating body of the fourth embodiment, and fig. 5 (b) is a front view of the rotating body of the fourth embodiment.

Fig. 6 (a) is a cross-sectional view of the rotating body of the fifth embodiment, and fig. 6 (b) is a front view of the rotating body of the fifth embodiment.

Fig. 7 is an external view of a conventional rotating body with plate-shaped fins.

Description of the symbols

101 … motor

102 … rotary body

102a … cylindrical part

102b … disc-shaped part

102c … circular ring-shaped bevel portion

102d … axial core part

103 … fluorescent substance

200 … light source device

210 … relay lens group

211 … excitation light source assembly

212 … exciting light source side condenser lens group

213 … polarization beam splitter

214 … quarter wave plate

215 … fluorescent body side condenser lens group

220 … color selection color wheel

221 … motor

240 … optical channel

250 … illuminating lens group

260 … light modulation device

271 … prism

272 … prism

280 … projection lens

290 … projection screen

301 … motor

302 … rotator

302a … cylindrical part

302b … disc-shaped part

302c … axial core part

303 … fluorescent substance

304 … concave part

305 … concave part

401 … electric machine

402 … rotator

402a … cylindrical part

402b … disc-shaped part

402c … axial core part

403 … phosphor

404 … recess

405 … recess

402d … spiral groove

402e … spiral groove

501 … electric motor

501H … motor hub (モータハブ)

502 … rotator

502a … cylindrical part

502b … disc-shaped part

502c … hub

503 fluorescent substance 503 …

502d … spiral groove

502e … spiral groove

504 … screw

602 … rotary body

602a … cylindrical part

603 … fluorescent substance

604 … rotor

605 … permanent magnet

606 … laminated core for stator

607 coil of stator 607 …

AIR … airflow

PR … having a red-emitting phosphor region

PG … having region of green-emitting phosphor

PY … area having phosphor emitting yellow light

RB … reflective region

RA … rotating shaft

Detailed Description

[ first embodiment ]

A light source device for a projection display device and a projection display device including the light source device according to a first embodiment of the present invention will be described with reference to the drawings. First, a rotating body included in the light source device will be described, and then the entire projection display device including the light source device will be described.

(rotating body of light Source device)

In fig. 1 (a) and (b), 101 denotes a motor, 102 denotes a rotating body, and 103 denotes a fluorescent material.

Fig. 1 (a) is a cross-sectional view of the rotor 102 taken along the rotation axis, and fig. 1 (b) is a front view of the rotor 102. In fig. 1 (a), the motor 101 is not illustrated in cross section.

The rotating body 102 includes a cylindrical portion 102a, a disc-shaped portion 102b, an annular inclined surface portion 102c, and a shaft center portion 102 d. Cylindrical portion 102a and disc-shaped portion 102b are connected via annular inclined surface portion 102c, and the surface of annular inclined surface portion 102c is coated with phosphor 103.

As shown in fig. 1 (b), the annular slope portion 102c has, on its surface: four stripe-shaped regions, i.e., a region PR having a phosphor emitting red light, a region PG having a phosphor emitting green light, a region PY having a phosphor emitting yellow light, and a reflection region RB reflecting excitation light. Each region is arranged on an arc centered on the rotation axis RA.

As rotor 102 rotates, regions PR, PG, and PY are sequentially irradiated with excitation light, and red, green, and yellow fluorescence are emitted, respectively. When the reflection region RB is irradiated with the excitation light (blue laser light), the blue light is reflected by the rotating body 102. The surface of annular slope 102c is preferably mirror-finished in advance so that the fluorescence emitted in region PR, region PG, and region PY can be efficiently emitted or the blue laser beam can be efficiently reflected in reflection region RB.

The axial center portion 102d of the rotating body 102 is fixed to the rotation shaft of the motor 101, and the rotating body 102 rotates along with the motor rotation shaft. The rotary body 102 is rotated at a high speed so that the projection display apparatus can display a color image at a high frame rate, specifically, for example, 7200rpm so as to correspond to a 120-screen-per-second color image display.

The rotary member 102 is made of a metal material having high thermal conductivity and high reflectance. For example, aluminum or an aluminum alloy is suitably used. The cylindrical portion 102a, the disc portion 102b, the annular inclined surface portion 102c, and the axial portion 102d may be manufactured separately and then joined to each other, but in order to reduce the manufacturing cost, it is preferable to form each portion by processing the entire base material.

In the present embodiment, the inner surface of the cylindrical portion 102a is provided with a groove provided in a spiral shape. When a surface closest to the rotation axis among the inner surfaces of the cylinder is taken as a reference, it is considered that a groove (concave portion) is provided, and when a bottom of the concave portion is taken as a reference, it is considered that a ridge (convex portion) extending in a spiral shape is provided. Alternatively, it is also conceivable to provide a concave-convex structure extending in a spiral shape.

In the present embodiment, as the spiral concave-convex structure, a spiral groove that is the same as or similar to the thread groove provided on the inner surface of the regular nut is provided. The pitch, which is the ratio of the angle of rotation of the helical groove to the distance traveled in the direction along the rotation axis RA, is constant, and the helical line of the helix extends at least one revolution, i.e., 360 degrees or more, around the inner surface of the cylinder. When the rotating body is rotated, the spiral grooves induce the air flow, and the induced air flow is uniform in the direction of the rotation axis by using the spiral with a fixed pitch as described above, thereby suppressing the generation of turbulence and contributing to the reduction of noise. Further, since the air flow is generated inside the cylindrical portion 102a, the rotating body itself functions as a sound insulator, and noise can be suppressed to a low level.

The spiral direction may be a clockwise direction or a counterclockwise direction when the light is advanced in a direction away from the motor 101, but it is preferable to be a direction in which the air flow caused by the rotation at the time of light emission flows toward the phosphor. In other words, the rotating direction of the rotating body may be set to a direction in which the air flow caused by the spiral uneven structure flows toward the phosphor. In the present embodiment, when the rotating body rotates during light emission, AIR flows toward the inner surface of annular slope portion 102c where phosphor 103 is provided, as shown as AIR flow AIR in fig. 1 (a), and thus the phosphor can be cooled efficiently.

The spiral groove of the present embodiment can be easily provided by cutting the inner surface of the cylindrical portion 102a of the rotating body 102 using, for example, a tap for thread cutting.

As described above, the light source of the present embodiment can efficiently cool the phosphor using the rotating body provided with the spiral groove. By setting the pitch of the spiral provided on the inner surface of the cylindrical portion to be constant, it is possible to suppress the generation of turbulence, and also to suppress noise due to wind shear noise to a low level even when the cylindrical portion is rotated at a high speed of, for example, 7200 rpm. Further, the rotating body of the present embodiment is easier to manufacture and handle than a rotating body including plate-shaped fins, and can be reduced in cost.

Next, a light source device including the rotating body and a projection display device using the light source device as an illumination light source will be described.

(light source device)

In fig. 2, a portion surrounded by a broken line is a light source device 200 including the rotating body 102.

First, the excitation light source assembly 211 includes a plurality of blue laser light sources arranged in an array and a plurality of collimator lenses arranged corresponding to the respective blue laser light sources, and the blue laser light sources and the collimator lenses are modularized. The blue laser light source used in the light source module is, for example, a semiconductor laser that emits S-polarized light having a wavelength of 440 nm.

Each module of the excitation light source assembly 211 includes a light emitting device array in which blue laser light sources are arranged in a matrix of 2 × 4. However, the size of the matrix arrangement included in one module is not limited to this example, and may be a larger-size matrix arrangement, or may be a matrix arrangement in which the number of vertical and horizontal directions is the same. The light output from each laser light source is emitted from the excitation light source assembly 211 as substantially parallel light rays by the action of the collimator lens.

The S-polarized blue laser light emitted from the excitation light source assembly 211 passes through the excitation light source side lens group 212, is reflected by the polarization beam splitter 213, and is condensed by the phosphor side condenser lens group 215 on the phosphor provided on the inclined surface of the rotating body 102. As described above, the fluorescent material emitting red light, green light, and yellow light is disposed in the region on the inclined surface of rotating body 102 irradiated with the excitation light. The polarization beam splitter 213 is a selective mirror, reflects the blue excitation light as S-polarized light, and transmits the fluorescence having inconsistent polarization and the P-polarized blue light reflected by the rotating body 102 and returned via the quarter-wave plate 214. The fluorescence emitted from the phosphor is condensed by the phosphor-side condenser lens group 215, passes through the polarization beam splitter 213, and is emitted toward the relay lens group 210.

(projection display device)

The projection display apparatus of fig. 2 uses the light source apparatus 200 described above as an illumination light source, and further includes a relay lens group 210, a light color selection color wheel 220, a motor 221, a light tunnel 240, an illumination lens group 250, a light modulation device 260, a prism 271, a prism 272, and a projection lens 280. There are also cases where the projection screen 290 is further provided.

The relay lens group 210 is a lens group for focusing the light emitted from the light source device 200 to the entrance port of the light tunnel 240 by setting a predetermined NA so as to be suitable for the F value of the projection lens 280. The relay lens group does not necessarily have to be constituted by one lens. In addition, in the case where NA is sufficient, the relay lens group may not be provided.

The light color selection color wheel 220 is a plate-shaped rotating body that is driven by a motor 221 to rotate about a rotation axis Ac, and includes red (R), green (G), and yellow (Y) color filters and a fan-shaped notch (light transmission section) for transmitting blue light. The color filters of the respective colors are provided to remove light in unnecessary wavelength regions to improve color purity of display light. However, since blue light is laser light having high color purity, it is not necessary to provide a filter, and thus, a notch portion is provided.

The rotating body 102 having the phosphors is rotated in synchronization with the light color selecting color wheel 220, and the rotation timing is adjusted such that the red phosphor of the former emits light while the red filter is positioned on the light path, the green filter is positioned on the light path when the green phosphor emits light, the yellow filter is positioned on the light path when the yellow phosphor emits light, and the light transmitting section is positioned on the light path when the blue excitation light is reflected. In addition, when the luminescent color purity of the phosphor is sufficiently high, there may be a case where the light color selection color wheel may or may not be provided.

The illumination lens group 250 is a lens group that shapes light propagating through the optical channel 240 into a beam suitable for illuminating the light modulation device 260, and is composed of a single or a plurality of lenses.

Prism 271 and prism 272 together form a Total Internal Reflection (TIR) prism. The TIR prism totally internally reflects the illumination light to enter the light modulator 260 at a predetermined angle, and transmits the reflected light modulated by the light modulator 260 toward the projection lens 280.

The light modulation Device 260 modulates incident light based on an image signal, and uses a Digital Micromirror Device (DMD) in which Micromirror devices are arranged in an array. Other reflective light modulation devices, such as reflective liquid crystal devices, may be used.

The projection lens 280 is a lens for projecting the light modulated by the light modulation device 260 as an image, and is composed of a single or a plurality of lenses.

The projection screen 290 is used when constituting a rear projection type display device, and is often provided also in a front projection type display device, but is not necessarily provided when a user projects a picture onto an arbitrary wall surface or the like.

The overall operation of the projection display device will be described below.

The illumination light with suppressed color shading (color unevenness) emitted from the light source device is incident on the prism 271, which is a TIR prism, via the relay lens group 210, the light color selection color wheel 220, the light tunnel 240, and the illumination lens group 250. The light reflected by the total reflection surface of the prism 271 enters the light modulation device 260 at a predetermined angle.

The light modulation device 260 has micromirror devices arranged in an array, and drives the micromirror devices in accordance with respective color component signals of an image in synchronization with color switching of illumination light to reflect image light at a predetermined angle toward the prism 271. The image light passes through the prism 271 and the prism 272, is guided to the projection lens 280, and is projected onto the projection screen 290.

The projection display device of the present embodiment can display a high-luminance image with low noise because the light modulation element can be illuminated using the light source device having high power and high degree of silence.

[ second embodiment ]

A second embodiment including a rotating body having a structure different from that of the first embodiment will be described.

(rotating body of light Source device)

In fig. 3 (a), (b), and (c), 301 denotes a motor, 302 denotes a rotating body, and 303 denotes a fluorescent material.

Fig. 3 (a) is a cross-sectional view of rotor 302 taken along the rotation axis, fig. 3 (b) is a front view of rotor 302, and fig. 3 (c) is an external view of rotor 302. In fig. 3 (a), the motor 301 is not illustrated in cross section.

The rotating body 302 includes a cylindrical portion 302a, a disc-shaped portion 302b, and a shaft center portion 302 c. The cylindrical portion 302a and the axial core portion 302c are joined via a disc-shaped portion 302 b. In order to reduce the weight of the rotating body 302 and improve the air cooling efficiency, a concave portion 304 and a concave portion 305 are provided across the disc-shaped portion 302 b.

Further, a band-shaped fluorescent material 303 is provided on the outer surface of the cylindrical portion 302a on the tip side. Although not shown, the fluorescent material 303 in a band shape includes: a region PR having a phosphor emitting red light, a region PG having a phosphor emitting green light, and a region PY having a phosphor emitting yellow light. A reflection region RB that reflects the excitation light is further provided adjacent to the band-shaped fluorescent material 303 on the outer surface.

As rotor 302 rotates, region PR, region PG, and region PY are sequentially irradiated with excitation light, and red, green, and yellow fluorescence are emitted, respectively. When the reflection region RB is irradiated with the excitation light (blue laser light), the blue light is reflected by the rotating body 302. The surface of the outer surface of the cylindrical portion 302a on the distal end side is preferably mirror-finished in advance so that the fluorescence emitted in the region PR, the region PG, and the region PY can be efficiently emitted or the blue laser beam can be efficiently reflected in the reflection region RB.

Axial center portion 302c of rotary body 302 is fixed to the rotation shaft of motor 301, and rotary body 302 rotates with the motor rotation shaft. The rotating body 302 rotates at a high speed so that the projection display apparatus can display a color image at a high frame rate, specifically, for example, 7200rpm so as to correspond to a 120-screen-per-second color image display.

The rotating body 302 is formed of a metal material having high thermal conductivity and high reflectance. For example, aluminum or an aluminum alloy is suitably used. Although the cylindrical portion 302a, the disc-shaped portion 302b, and the axial portion 302c may be manufactured separately and then joined, it is preferable to form each portion by machining the entire base material in order to reduce manufacturing costs.

In the present embodiment, a groove 302d provided in a spiral shape is provided on the outer surface of the cylindrical portion 302 a. The groove (concave portion) may be provided when a surface of the cylindrical outer surface farthest from the rotation axis is taken as a reference, and the ridge (convex portion) extending in a spiral shape may be provided when the bottom of the concave portion is taken as a reference. Alternatively, it is also conceivable to provide a concave-convex structure extending in a spiral shape.

In the present embodiment, as shown in the external view of fig. 3 (c), a spiral groove similar to or the same as a thread groove provided in a general bolt is used as the spiral groove 302 d. The pitch, which is the ratio of the rotation angle of the spiral groove 302d to the distance of advance in the direction along the rotation axis RA, is constant, and the spiral line of the spiral extends so as to rotate at least one turn (360 degrees) around the outer surface of the cylinder. When the rotating body is rotated, the spiral grooves induce the air flow, and the induced air flow is uniform in the direction of the rotation axis by using the spiral with a fixed pitch as described above, thereby suppressing the generation of turbulence and contributing to the reduction of noise.

The spiral direction may be a direction rotating clockwise or counterclockwise when advancing in a direction away from the motor 301, but is preferably a direction in which an air flow caused by rotation at the time of light emission flows toward the phosphor. That is, in the present embodiment, when the rotating body rotates during light emission, AIR flows toward the outer surface on the distal end side where the fluorescent body 303 is provided, as shown as AIR in fig. 3 (a), and therefore, the fluorescent body 303 can be efficiently cooled.

The spiral groove of the present embodiment can be easily provided by cutting the outer surface of the cylindrical portion 302a of the rotating body 302 using, for example, a tap for thread cutting.

As described above, the light source of the present embodiment can efficiently cool the phosphor using the rotating body provided with the spiral groove. By setting the pitch of the spiral provided on the outer surface of the cylindrical portion to be constant, it is possible to suppress the generation of turbulence, and also to suppress noise due to wind shear noise to a low level even when the cylindrical portion is rotated at a high speed of, for example, 7200 rpm. The rotating body of the present embodiment is easier to manufacture and handle than a conventional rotating body having plate-shaped fins, and can be reduced in cost.

The light source device including the rotating body of the present embodiment can be used in the projection display device described with reference to fig. 2, as in the light source device of the first embodiment. Since the light source device has basically the same configuration, description thereof will be omitted, but the light source device of the present embodiment differs in that the rotational axis RA of the rotating body is laid out in the direction along the Y axis of fig. 2 because the fluorescent material is provided on the side surface of the rotating body. The projection display device of the present embodiment can display a high-luminance image with low noise because the light modulation element can be illuminated using the light source device having high power and high degree of silence.

[ third embodiment ]

A third embodiment including a rotating body having a structure different from the first and second embodiments will be described.

(rotating body of light Source device)

In fig. 4 (a) and (b), 401 denotes a motor, 402 denotes a rotating body, and 403 denotes a fluorescent material.

Fig. 4 (a) is a cross-sectional view of the rotor 402 taken along the rotation axis, and fig. 4 (b) is a front view of the rotor 402. In fig. 4 (a), a cross section of the inside of the motor 401 is not shown.

The rotating body 402 includes a cylindrical portion 402a, a disc-shaped portion 402b, and a shaft portion 402 c. The cylindrical portion 402a and the axial portion 402c are joined via a disc-shaped portion 402 b. In order to reduce the weight of the rotating body 402 and improve the air cooling efficiency, a concave portion 404 and a concave portion 405 are provided across the disc-shaped portion 402 b.

Further, a band-shaped fluorescent material 403 is provided in an annular portion of the end surface on the front end side of the cylindrical portion 402 a. As shown in fig. 4 (b), the phosphor 403 in a band shape includes: a region PR having a phosphor emitting red light, a region PG having a phosphor emitting green light, and a region PY having a phosphor emitting yellow light. In the annular portion, a reflection region RB that reflects excitation light is provided in parallel with the band-shaped phosphor.

As rotating body 402 rotates, regions PR, PG, and PY are sequentially irradiated with excitation light, and red, green, and yellow fluorescence are emitted, respectively. When the reflection region RB is irradiated with the excitation light (blue laser light), the blue light is reflected by the rotating body 402. The surface of the end face on the distal end side of the cylindrical portion 402a is preferably mirror-finished in advance so that the fluorescence emitted in the region PR, the region PG, and the region PY can be efficiently emitted or the blue laser beam can be efficiently reflected in the reflection region RB.

A shaft center portion 402c of the rotating body 402 is fixed to a rotation shaft of the motor 401, and the rotating body 402 rotates along with the motor rotation shaft. The rotating body 402 rotates at a high speed so that the projection display apparatus can display a color image at a high frame rate, specifically, for example, 7200rpm so as to correspond to a 120-screen-per-second color image display.

The rotating body 402 is made of a metal material having high thermal conductivity and high reflectance. For example, aluminum or an aluminum alloy is suitably used. The cylindrical portion 402a, the disc portion 402b, and the axial portion 402c may be manufactured separately and then joined, but in order to reduce the manufacturing cost, it is preferable to form each portion by processing the entire base material.

In the present embodiment, the

grooves

402d and 402e provided in a spiral shape are provided on both the outer surface and the inner surface of the cylindrical portion 402 a. Alternatively, it is also conceivable to provide a concave-convex structure extending in a spiral shape.

In the present embodiment, as the spiral groove 402d, a spiral groove that is the same as or similar to a thread groove provided in a general bolt is used. As the spiral groove 402e, a spiral groove the same as or similar to a thread groove provided in a general nut is used.

The pitch, which is the ratio of the rotation angle of the

spiral grooves

402d and 402e to the distance advanced in the direction along the rotation axis RA, is fixed, and the spiral line of the spiral extends so as to rotate at least one turn (360 degrees) around the inner surface or the outer surface of the cylinder. When the rotating body is rotated, the spiral grooves induce the air flow, and the induced air flow is uniform in the direction of the rotation axis by using the spiral with a fixed pitch as described above, thereby suppressing the generation of turbulence and contributing to the reduction of noise.

The spiral direction may be a clockwise rotation direction or a counterclockwise rotation direction when proceeding in a direction away from the motor 401, but is preferably a direction in which an air flow caused by rotation at the time of light emission flows toward the phosphor side at the front end of the cylindrical portion 402 a. That is, in the present embodiment, when the rotating body rotates during light emission, AIR flows toward the front end side where the phosphor is provided as shown as AIR in fig. 4 (a), and therefore the phosphor can be cooled efficiently.

The spiral groove of the present embodiment can be easily provided by cutting the outer surface and the inner surface of the cylindrical portion 402a of the rotating body 402 using, for example, a cutting tool for thread cutting.

As described above, the light source of the present embodiment can efficiently cool the phosphor using the rotating body provided with the spiral groove. By fixing the pitches of the spirals provided on the inner surface and the outer surface of the cylindrical portion, it is possible to suppress the generation of turbulence, and to suppress noise due to wind shear noise to a low level even when the cylindrical portion is rotated at a high speed of, for example, 7200 rpm. Further, the rotating body of the present embodiment is easier to manufacture and handle than a rotating body including plate-shaped fins, and can be reduced in cost.

The light source device including the rotating body of the present embodiment can be used in the projection display device described with reference to fig. 2, as in the light source device of the first embodiment. Since the light source device has basically the same configuration, description thereof will be omitted, but the light source device of the present embodiment differs in that the fluorescent material is provided on the end surface of the cylindrical portion of the rotating body (the front surface of the rotating body), and the rotation axis RA of the rotating body is arranged in the direction along the X axis in fig. 2. The projection display device of the present embodiment can display a high-luminance image with low noise because the light modulation element can be illuminated using the light source device having high power and high degree of silence.

[ fourth embodiment ]

A fourth embodiment in which the method of fixing the rotating body to the motor is different from the third embodiment will be described.

In fig. 5 (a) and (b), 501 denotes a motor, 502 denotes a rotating body, and 503 denotes a fluorescent material.

Fig. 5 (a) is a cross-sectional view of the rotor 502 cut along the rotation axis, and fig. 5 (b) is a front view of the rotor 502. In fig. 5 (a), a cross section of the inside of the motor 501 is not shown.

In the third embodiment, the axial center portion 402c of the rotating body 402 is fixed to the rotating shaft of the motor 401, but in the present embodiment, the rotating shaft of the motor includes a motor hub 501H at the tip end, and the rotating body 502 is fixed to the motor hub 501H.

The rotating body 502 includes a cylindrical portion 502a, a disc-shaped portion 502b, and a shaft portion 502 c. The cylindrical portion 502a and the axial core portion 502c are joined via the disc-shaped portion 502 b.

Not shown in the sectional view of fig. 5 (a), but as seen in the front view of fig. 5 (b), the disc-shaped portion 502b is fixed to the motor hub 501H by four screws 504, and the rotary body 502 rotates with the rotation of the motor. The rotating body 502 is rotated at a high speed so that the projection display apparatus can display a color image at a high frame rate, specifically, for example, 7200rpm so as to correspond to a 120-screen-per-second color image display.

Further, a band-shaped fluorescent material 503 is provided in an annular portion of the end surface of the cylindrical portion 502a on the tip side. As shown in fig. 5 (b), the fluorescent material 503 in a band shape includes: a region PR having a phosphor emitting red light, a region PG having a phosphor emitting green light, and a region PY having a phosphor emitting yellow light. In the annular portion, a reflection region RB that reflects excitation light is provided in parallel with the band-shaped phosphor.

As the rotary 502 rotates, the regions PR, PG, and PY are sequentially irradiated with excitation light, and red, green, and yellow fluorescence are emitted, respectively. When the reflection region RB is irradiated with the excitation light (blue laser light), the blue light is reflected by the rotating body 502. The surface of the end face on the distal end side of the cylindrical portion 502a is preferably mirror-finished in advance so that the fluorescence emitted in the region PR, the region PG, and the region PY can be efficiently emitted or the blue laser light can be efficiently reflected in the reflection region RB.

The rotating body 502 is formed of a metal material having high thermal conductivity and high reflectance. For example, aluminum or an aluminum alloy is suitably used. Although the cylindrical portion 502a, the disc-shaped portion 502b, and the axial portion 502c may be manufactured separately and then joined, it is preferable to form each portion by processing the entire base material in order to reduce manufacturing costs.

In the present embodiment, the

grooves

502d and 502e provided in a spiral shape are provided on both the outer surface and the inner surface of the cylindrical portion 502 a. Alternatively, it is also conceivable to provide a concave-convex structure extending in a spiral shape.

In the present embodiment, as the spiral groove 502d, a spiral groove that is the same as or similar to a thread groove provided in a general bolt is used. As the spiral groove 502e, a spiral groove the same as or similar to a thread groove provided in a general nut is used. The ratio of the rotation angle of the

spiral grooves

502d and 502e to the distance of advance in the direction along the rotation axis RA, that is, the pitch is fixed, and the spiral line of the spiral extends so as to rotate at least one turn (360 degrees) around the inner surface or the outer surface of the cylinder. When the rotating body is rotated, the spiral grooves induce the air flow, and the induced air flow is uniform in the direction of the rotation axis by using the spiral with a fixed pitch as described above, thereby suppressing the generation of turbulence and contributing to the reduction of noise.

The spiral direction may be a clockwise rotation direction or a counterclockwise rotation direction when proceeding in a direction away from the motor 501, but is preferably a direction in which an air flow caused by rotation at the time of light emission flows toward the phosphor side at the front end of the cylindrical portion 502 a. That is, in the present embodiment, when the rotating body rotates during light emission, AIR flows toward the front end side where the phosphor is provided as shown as AIR in fig. 5 (a), and therefore the phosphor can be cooled efficiently.

The spiral groove of the present embodiment can be easily provided by cutting the outer surface and the inner surface of the cylindrical portion 502a of the rotating body 502 using, for example, a tap for thread cutting.

The light source device including the rotating body of the present embodiment can be used in the projection display device described with reference to fig. 2, as in the light source device of the first embodiment. Since the light source device has basically the same configuration, description thereof will be omitted, but the light source device of the present embodiment differs in that the fluorescent material is provided on the end surface of the cylindrical portion of the rotating body (the front surface of the rotating body), and the rotation axis RA of the rotating body is arranged in the direction along the Y axis in fig. 2. The projection display device of the present embodiment can display a high-luminance image with low noise because the light modulation element can be illuminated using the light source device having high power and high degree of silence.

[ fifth embodiment ]

A fifth embodiment in which the motor type is different from the first to fourth embodiments will be described.

Various types of motors can be used as the motor for driving the rotating body, and in the present embodiment, in order to improve the space utilization rate in the apparatus, an outer rotor type dc brushless motor is used so that the length from the front end of the rotating body to the rear end of the motor can be shortened.

Fig. 6 (a) is a cross-sectional view of the rotating body 602 taken along the rotation axis, and fig. 6 (b) is a front view of the rotating body 602.

In fig. 6 (a), 602 denotes a rotor, 603 denotes a phosphor, 604 denotes a rotor of an outer rotor type dc brushless motor, 605 denotes a permanent magnet provided on the rotor, 606 denotes a laminated core of a stator, and 607 denotes a coil of the stator. The rotating body 602 and the rotor 604 are aligned and fixed with the rotation axes concentric and are integrated.

A fluorescent material 603 having a band shape is provided on the front surface side of the rotating body 602. As shown in fig. 6 (b), the phosphor 603 in a band shape includes: a region PR having a phosphor emitting red light, a region PG having a phosphor emitting green light, and a region PY having a phosphor emitting yellow light. On the front surface side of the rotating body 602, a reflection region RB that reflects excitation light is provided in parallel with the band-shaped fluorescent material, and forms a circular ring as a whole.

As the rotating body 602 rotates, the regions PR, PG, and PY are sequentially irradiated with excitation light, and red, green, and yellow fluorescence are emitted, respectively. When the reflection region RB is irradiated with the excitation light (blue laser light), the blue light is reflected by the rotating body 602. The base surface of the ring is preferably mirror-finished in advance so that the fluorescence emitted in the regions PR, PG, and PY can be efficiently emitted or the blue laser light can be efficiently reflected in the reflective region RB.

The rotating body 602 is made of a metal material having high thermal conductivity and high reflectance. For example, aluminum or an aluminum alloy is suitably used. The rotating body 602 rotates at a high speed so that the projection display apparatus can display a color image at a high frame rate, specifically, for example, 7200rpm so as to correspond to a color image display of 120 screens per second.

In the present embodiment, the outer surface of the cylindrical portion 602a is provided with a groove provided in a spiral shape. The groove (concave portion) may be provided when a surface of the cylindrical outer surface farthest from the rotation axis is taken as a reference, and the ridge (convex portion) extending in a spiral shape may be provided when the bottom of the concave portion is taken as a reference. Alternatively, it is also conceivable to provide a concave-convex structure extending in a spiral shape.

The pitch, which is the ratio of the angle of rotation of the helical groove to the distance traveled in the direction along the rotation axis RA, is constant, and the helical line of the helix extends so as to rotate at least one revolution (360 degrees) around the outer surface of the cylinder. When the rotating body is rotated, the spiral grooves induce the air flow, and the induced air flow is uniform in the direction of the rotation axis by using the spiral with a fixed pitch as described above, thereby suppressing the generation of turbulence and contributing to the reduction of noise.

The spiral direction may be a clockwise direction or a counterclockwise direction when the light source advances in a direction away from the motor, but it is preferable to be a direction in which the air flow caused by the rotation at the time of light emission flows toward the phosphor. That is, in the present embodiment, when the rotating body rotates during light emission, AIR flows toward the outer surface on the distal end side where the fluorescent material 603 is provided, as shown as AIR in fig. 6 (a), and therefore, the fluorescent material 603 can be efficiently cooled.

The spiral groove of the present embodiment can be easily provided by cutting the outer surface of the cylindrical portion 602a of the rotating body 602 using, for example, a tap for thread cutting.

As described above, the light source of the present embodiment can efficiently cool the phosphor using the rotating body provided with the spiral groove. By setting the pitch of the spiral provided on the outer surface of the cylindrical portion to be constant, it is possible to suppress the generation of turbulence, and also to suppress noise due to wind shear noise to a low level even when the cylindrical portion is rotated at a high speed of, for example, 7200 rpm. Further, the rotating body of the present embodiment is easier to manufacture and handle than a rotating body including plate-shaped fins, and can be reduced in cost.

The light source device including the rotating body of the present embodiment can be used in the projection display device described with reference to fig. 2, as in the light source device of the first embodiment. Since the light source device has basically the same configuration, description thereof will be omitted, but the light source device of the present embodiment differs in that the rotational axis RA of the rotating body is laid out in the direction along the X axis of fig. 2 because the fluorescent material is provided in front of the rotating body. The projection display device of the present embodiment can display a high-luminance image with low noise because the light modulation element can be illuminated using the light source device having high power and high degree of silence.

Further, since the outer rotor type dc brushless motor is used, the length from the front end of the rotating body to the rear end of the motor can be shortened, and the space utilization rate in the apparatus can be improved. In the above embodiment, the fluorescent material and the rotating body having the spiral grooves are joined to the outer rotor, but the fluorescent material and the spiral grooves may be provided on the outer surface of the rotor itself of the outer rotor type dc brushless motor, depending on the case.

[ other embodiments ]

In the above-described embodiments, the concave-convex structure extending in the spiral shape is provided on one or both of the outer side surface and the inner side surface of the cylindrical portion of the rotating body, but the rotating body of the present invention is not limited to the above-described examples, and various modifications and combinations may be made. For example, the combination of the form of the rotating body and the type of the motor (inner rotor motor, outer rotor motor, etc.) is not limited to the example of the above embodiment.

The portion of the rotating body provided with the spiral concave-convex structure need not be a complete cylindrical portion having the same radius in the rotation axis direction, and may be, for example, an outer surface or an inner surface of a hollow conical shape having a radius varying in the rotation axis direction. Further, the solid portion may be provided on the outer surface of the solid portion, even if the side surface of the hollow cylindrical portion is not provided.

The rotation speed of the rotator is not limited to 7200rpm as exemplified in the embodiment, and may be set to 10800rpm when a color image is displayed at a display speed of 180 screens/second, for example. The rotating body having a spiral structure of the present invention has a characteristic that wind shear noise is small even when rotating at a high speed, and thus can be applied to projection display devices of various specifications.

In the above-described embodiment, the helical uneven structure which is the same as or similar to the thread groove used in the ordinary bolt (male thread) or nut (female thread) is used, because the uneven structure is required to have an equal pitch in order to prevent turbulence from occurring, and the manufacturing is also easy. The cross-sectional shape of the concave portion or the convex portion may be, for example, a shape used for a thread such as a triangular thread, a square thread, a trapezoidal thread, a zigzag thread, or a circular thread, and the number of thread teeth may be appropriately selected in accordance with the generation efficiency of the air flow and the noise. The spiral uneven structure of the present invention is easier to process and handle than a conventional rotating body having plate-shaped fins, and can be manufactured at a lower cost.

However, since the spiral concave-convex structure of the present invention is used not for connecting members but for generating an air flow for cooling, various modifications are possible with respect to factors such as the winding direction, the number of heads, the shape, diameter, and pitch of the screw groove. For example, these elements need not be completely fixed throughout the entire area of the spiral uneven structure, and may be partially modified. The shape of the recess and projection used for the conventional screw is not limited as long as the air flow can be induced by the rotation.

Further, the base and the reflective surface of the fluorescent surface of the rotating body are preferably mirror-finished as described above to improve the light utilization efficiency, but the surface of the rotating body other than the base and the reflective surface of the fluorescent surface may be a rough oxide film with fine irregularities (natural color) or a black rough oxide film, so that the heat dissipation efficiency can be further improved by increasing the surface area.

The fluorescent material provided on the rotating body is not limited to the three colors R, B, Y exemplified in the embodiment, and the type and the number of colors may be changed.

Further, the side surface, the inclined surface, and the front surface of the rotating body are shown as examples of the position where the phosphor is provided, but the present invention is not limited thereto, and the phosphor may be provided at a plurality of positions by combining these positions on one rotating body, for example.

The projection display device using the light source of the present invention is not limited to the form illustrated in fig. 2, and various modifications are possible. For example, the light modulation device that modulates the illumination light from the light source is not limited to a reflective light modulation device such as a DMD or a reflective liquid crystal device. For example, a three-plate type projection display apparatus can also be constituted using a transmissive light modulation device such as a transmissive liquid crystal panel and a color separation optical system.

Claims

1. A light source device for a projection display device, comprising:

a rotating body made of metal;

a phosphor coated on the rotating body; and

an excitation light source that outputs excitation light for exciting the phosphor,

the rotating body has a concavo-convex structure extending in a spiral shape along a side surface thereof,

the rotating direction of the rotating body is a direction in which an air flow induced by the spirally extending concave-convex structure flows in the direction of the fluorescent material.

2. The light source device according to claim 1,

the rotating body has a cylindrical portion, and the spirally extending concave-convex structure is provided on at least one of an inner side surface and an outer side surface of the cylindrical portion.

3. The light source device according to claim 1 or 2,

the spirally extending concave-convex structure is provided so that the ratio of the rotation angle to the distance of advance in the direction of the rotation axis of the rotating body is constant.

4. The light source device according to claim 1,

the spiral of the concave-convex structure extending in the spiral shape is rotated by 360 degrees or more.

5. The light source device according to claim 1,

the phosphor is coated on the inclined surface of the rotating body.

6. The light source device according to claim 1,

the phosphor is coated on the front surface of the rotating body.

7. The light source device according to claim 1,

the fluorescent material is coated on the side surface of the rotating body.

8. A projection display device is characterized by comprising:

the light source device of any one of claims 1 to 7;

a light modulation device; and

and a projection lens.