JP2005202195A - Light source device and projection type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device suitable for a compact projection type display device, made compact and having high luminance, and also to provide a projection type display device using the light source device. <P>SOLUTION: The light source device has a solid light source 21 for emitting light, a compression means 30 for compressing a coolant, a heat radiation means 40 for radiating the heat of the compressed coolant to the outside, a decompression means 50 for decompressing the coolant whose heat has been radiated, and a heat absorption means 60 for making the decompressed coolant absorb the heat. The solid light source 21 and the heat absorption means 60 are thermally connected. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light source device and a projection display device.

  In recent years, projectors (projection display devices) have been reduced in size, increased in brightness, extended in lifetime, reduced in price, and the like. For example, with respect to miniaturization, the size of the liquid crystal panel (light modulation element) has been reduced from 1.3 inches diagonal to 0.5 inches, with the area ratio being slightly over 1/6.

On the other hand, miniaturization by using a light emitting diode (LED) light source which is a solid light source as a light source of a projector has been proposed. The LED light source has a merit as a light source for a projector, such as being small in size including a power source, capable of instantaneous lighting / extinguishing, and wide color reproducibility and long life. Further, since it does not contain harmful substances such as mercury, it is preferable from the viewpoint of environmental protection.
Japanese Patent Laid-Open No. 06-005923 Japanese Patent Application Laid-Open No. 07-099372

  However, in order to use an LED light source as a light source for a projector, the brightness as a light source is insufficient, and it is necessary to ensure at least the brightness of a discharge type light source lamp level (high brightness, low etendue). . Here, etendue is a numerical value represented by the product of the area and the solid angle, which is the spatial extent in which a luminous flux that can be effectively utilized exists, and is optically stored. As described above, since the liquid crystal panel is downsized and the etendue of the liquid crystal panel is becoming smaller, the etendue of the light source needs to be equal or less.

  However, as the brightness of the LED light source is increased, heat generation from the LED light source increases more and the luminous efficiency decreases as the temperature of the LED light source rises. Therefore, it is necessary to take some heat generation measures. In general, the forced air cooling method using a fan has insufficient cooling efficiency, and fan noise is a problem. Therefore, a method for forcibly cooling the LED light source using a liquid has been proposed. According to the liquid cooling method, an effect is also expected to eliminate the noise of the forced air cooling method (see, for example, Patent Documents 1 and 2).

  In the LED light source in Patent Document 1, a cooling material such as liquid nitrogen is allowed to flow around the LED, thereby forcibly cooling the LED and the cooling material in direct contact with each other. However, the configuration of the LED light source is complicated, such as the need for a heat insulating case, and the manufacture thereof is not practical. Therefore, there is a problem that it is difficult to ensure at least the brightness of the discharge type light source lamp.

  In the LED light source in Patent Document 2, an insulating inert liquid is sealed around an LED chip (light emitting chip) to cool the LED chip. However, there is no means for actively cooling the insulating inert liquid, the cooling effect is low, and it is difficult to cool the LED chip for a long time, and at least the brightness of the discharge type light source lamp level is ensured. There was a problem of difficulty.

  The present invention has been made in order to solve the above-described problems, and provides a small and high-brightness light source device suitable for a small projection display device and a projection display device using the light source device. Objective.

  In order to achieve the above object, a light source device according to the present invention includes a solid-state light source that emits light, a compression unit that compresses a refrigerant, a heat radiation unit that releases heat of the compressed refrigerant to the outside, and a refrigerant that has radiated heat. It has a pressure reducing means for reducing pressure and a heat absorbing means for absorbing heat by the reduced pressure refrigerant, and the solid light source and the heat absorbing means are thermally connected.

That is, in the light source device of the present invention, since the solid light source and the heat absorbing means are thermally connected, the light absorbing device is cooled by the refrigerant having a temperature lower than the ambient temperature in the heat absorbing means. After the refrigerant is compressed by the compression means and becomes high temperature and high pressure, the heat is released to the outside at the heat radiating section, and is adiabatically expanded by the pressure reduction means to become a low temperature and low pressure, and flows into the heat absorption means. . Therefore, the temperature difference between the solid light source and the refrigerant becomes large, and the cooling efficiency of the solid light source is improved. Therefore, the power that can be input to the solid light source can be increased, and the amount of light that can be emitted from the solid light source can be increased.
In addition, since the temperature of the refrigerant in the heat absorption means can be kept substantially constant without being affected by the ambient temperature, the cooling efficiency of the solid light source can be kept constant and high efficiency. Therefore, the amount of light that can be emitted from the solid light source can be increased without being affected by the ambient temperature.
Further, even if the area of the solid light source is reduced to reduce the etendue and the light source device is downsized, the solid light source can be cooled and the input power can be increased, so that high luminance can be maintained.

In order to realize the above-described configuration, more specifically, a circulation unit that circulates a liquid medium that transports heat generated from the solid light source is disposed between the solid light source and the heat absorption unit. It is desirable that a circulation means for circulating the liquid medium is disposed.
According to this configuration, since the circulation part through which the liquid medium circulates is disposed between the solid light source and the heat absorption means, the flow path through which the refrigerant circulates can be shortened. Since the flow path through which the refrigerant circulates includes a high pressure region and a low pressure region due to the compression means and the pressure reduction means, a configuration capable of withstanding the pressure difference from the surroundings is required. Then, since the thickness of the member which comprises a flow path etc. increases, size reduction of a light source can be achieved by shortening the flow path through which a refrigerant circulates.

More specifically, in order to realize the above-described configuration, it is desirable that a heat exchanging unit for transferring the heat of the liquid medium to the heat absorbing unit is disposed in the circulation unit.
According to this configuration, by arranging the heat exchange means in the circulation part, the heat of the liquid medium is more easily transferred to the refrigerant. That is, for example, the amount of heat transfer can be increased by using a material having high thermal conductivity for the heat exchange means, or by increasing the contact area between the heat exchange means and the heat absorption means. Efficiency can be improved.

  A projection display device according to the present invention includes a light source device that emits light, a light modulation unit that modulates light from the light source device, and a projection unit that projects light modulated by the light modulation unit. A light source device is the light source device of the present invention.

That is, the projection display device of the present invention includes the light source device of the present invention,
The size of the projection display device can be reduced, and the brightness of the displayed image can be improved.

[Light source device]
[First Embodiment]
Hereinafter, a light source device according to a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic view of a light source device according to the present invention.
As shown in FIG. 1, the light source device 10 includes a light source unit 20 that emits light, a compressor (compression unit) 30 that compresses the refrigerant to high temperature and high pressure, and a radiator that releases heat of the compressed refrigerant to the outside. (Heat dissipation means) 40, an expansion valve (pressure reduction means) 50 for adiabatically expanding and depressurizing the radiated refrigerant, and a heat absorber (heat absorption means) 60 for absorbing the heat generated in the light source by the reduced pressure refrigerant. It is configured.

As shown in FIG. 1, the light source unit 20 includes an LED chip (solid light source) 21 that emits light, a reflection unit 22 that reflects the light emitted to the side to the illumination area, and the emitted light. And a lens 23 that condenses or collimates the light toward the illumination area.
The LED chip 21 is placed on the heat absorber 60. The reflector 22 is disposed on the same plane as the LED chip 21 and is formed in an annular shape centering on the LED chip 21 in plan view. On the surface of the reflecting portion 22 that faces the LED chip 21, a reflecting surface that is inclined outward toward the illuminated region is formed.

  The lens 23 is disposed on the reflecting portion 22, and the upper portion of the lens 23 is formed in a convex shape so that the light emitted from the LED chip 21 is condensed or collimated to the illuminated area. The lens 23 is made of a material having an optical function of transmitting the light emitted from the LED chip 21 without being damaged, for example, glass, acrylic resin, polycarbonate, or the like.

As the compressor 30, a known type of compressor such as a rotary compressor, a piston compressor, a scroll compressor, or the like can be used, and the compressor 30 is not particularly limited.
The radiator 40 includes, for example, heat radiation fins 41 formed of a metal such as Fe, Cu, Al, Mg, or a material having excellent thermal conductivity, and the surface area is increased by the fins. Increases heat dissipation capability.

The heat absorber 60 is made of, for example, a metal such as Fe, Cu, Al, or Mg or a material that includes these and has excellent thermal conductivity. Preferably, only the surface on which the LED chip 21 is placed is preferably formed from the above-described material, and more preferably, only the contact surface with the LED chip 21 is formed from the above-described material. .
Various refrigerants such as CFC-12, HFC-134a, HFC-410a, or CO2, which is a so-called natural refrigerant, can be used as the refrigerant, and are not particularly limited.

As described above, the radiator 40 and the expansion valve 50 may be directly connected by piping.
As shown in FIG. 2, a receiver 45 that separates the liquefied refrigerant in the radiator 40 and preferentially sends the liquefied refrigerant to the expansion valve 50 may be disposed between the radiator 40 and the expansion valve 50. Good. By disposing the receiver 45, liquid refrigerant is always supplied to the expansion valve 50 and the heat absorber 60, so that fluctuations in the heat absorption capability of the heat absorber 60 can be suppressed, and stable cooling capability can be exhibited.

Next, the operation of the light source device 10 having the above configuration will be described.
First, light emission from the light source unit 20 will be described.
When power is supplied to the LED chip 21, part of the supplied power is converted into light, and light is emitted from the LED chip 21 toward the periphery. The light emitted upward propagates through the lens 23 and is condensed or collimated toward the illuminated area and emitted. Further, the light emitted to the side and incident on the reflecting portion 22 is reflected toward the lens 23 and is condensed or collimated toward the illuminated area and emitted.

Next, cooling of the light source unit 20 will be described.
The remainder of the electric power supplied to the LED chip 21 is converted into heat and transmitted from the LED chip 21 to the heat absorber 60. The heat transferred to the heat absorber 60 is absorbed by the low-temperature and low-pressure liquid refrigerant flowing through the heat absorber 60. The liquid refrigerant that has absorbed the heat evaporates and vaporizes, becomes a gaseous refrigerant, and is sucked into the compressor 30. The gaseous refrigerant is compressed by the compressor 30, becomes a high-temperature and high-pressure gaseous refrigerant, and flows into the radiator 40. The high-temperature and high-pressure refrigerant releases its heat (including heat taken from the LED chip 21) to the outside in the radiator 40 and condenses to become a liquid refrigerant. The refrigerant that has become liquid is decompressed and expanded by flowing through the expansion valve 50, becomes a low-temperature and low-pressure refrigerant, flows again into the heat absorber 60, and absorbs the heat of the LED chip 21.
As described above, in the radiator 40 and the heat absorber 60, the refrigerant may be in a gas-liquid two-layer state. For example, as in the supercritical cycle using CO2, the refrigerant is set in the supercritical state in the radiator 40. There is no particular limitation.

According to said structure, since LED chip 21 is mounted on the heat absorber 60, the LED chip 21 is cooled by the refrigerant | coolant used as the temperature lower than the circumference | surroundings in the heat absorber 60. FIG. Therefore, the temperature difference between the LED chip 21 and the refrigerant increases, and the cooling efficiency of the LED chip 21 is improved. Therefore, the power that can be input to the LED chip 21 can be increased, and the amount of light that can be emitted from the LED chip 21 is increased. be able to.
In addition, since the refrigerant that has taken heat from the LED chip 21 is changed to a high-temperature and high-pressure refrigerant by the compressor 30, the heat taken from the LED chip 21 in the radiator 40 can be easily released to the surroundings. The cooling efficiency of 21 can be improved.

  Further, since the temperature of the refrigerant in the heat absorber 60 can be kept substantially constant without being affected by the ambient temperature, the cooling efficiency of the LED chip 21 can be kept constant and high efficiency. Therefore, the amount of light that can be emitted from the solid light source can be increased without being affected by the ambient temperature.

  Further, even if the area of the LED chip 21 is reduced to reduce the etendue and the light source device 10 is downsized, the LED chip 21 can be cooled, so that the input power can be increased and high luminance can be maintained. .

  In the present embodiment, the description has been made by adapting to a form using a so-called expansion valve cycle using the expansion valve 50. However, the present embodiment is not limited to the expansion valve cycle, and as shown in FIG. Various other refrigeration cycles such as a so-called accumulator cycle in which an orifice 56 which is a throttle is used instead of the receiver 45 and an accumulator 46 is arranged between the compressor 30 and the radiator 40 instead of the receiver 45 can be used.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
The basic configuration of the light source device according to the present embodiment is the same as that of the first embodiment, but the configuration between the light source unit and the heat absorber is different from that of the first embodiment. Therefore, in the present embodiment, only the periphery of the configuration between the light source unit and the heat absorber will be described using FIG. 4, and description of the light source unit and the like will be omitted.

FIG. 4 is a schematic view of a light source device according to the present invention.
As shown in FIG. 4, the light source device 70 includes a light source unit 20 that emits light, a compressor 30 that compresses the refrigerant, a radiator 40 that releases the heat of the refrigerant to the outside, and an expansion valve 50 that decompresses the refrigerant. A heat absorber 60 that causes the refrigerant to absorb heat, a mounting part 71 that mounts the light source part 20, and a first circulation part (circulation part) 75a that forms part of the circulation channel C through which the liquid L circulates. A second circulation part (circulation part) 75b that also forms a part of the circulation channel C, a circulation pump (circulation means) 80 that is disposed in the second circulation part 75b and circulates the liquid L; Similarly, the heat exchanger (heat exchanging means) 85 that is disposed in the second circulation portion 75 b and releases the heat of the liquid L to the heat absorber 60 is schematically configured.

The mounting unit 71 is connected to a mounting plate 72 on which the light source unit 20 is mounted, a base 73 that forms a part of the circulation channel C together with the mounting plate 72, and a first circulation unit 75a described later. And a flange 74 to be used.
The mounting plate 72 is formed of a metal material such as Cu or Al having high thermal conductivity and conductivity, and is formed in the same shape as the plan view of the base 73. Further, the platen 72 is formed to have a thickness smaller than the thickness of the side wall and the bottom of the base 73.

The base 73 is formed in a U-shape consisting of opposing side walls and a bottom surface, and by placing the mounting plate 72 so as to face the bottom surface, a part of the circulation channel C is formed therein. .
The flange 74 is formed with a hole (not shown) through which a coupling member such as a bolt used for coupling with a circulating portion 75a described later is inserted. The connecting member may be the above-described bolt or a rivet, or may be formed by forming screw holes in the flanges of the first circulating portion 75a and the second circulating portion 75b, which will be described later, and using screws. They may be screwed together and various other coupling methods can be used.

As shown in FIG. 4, the first circulation part 75 a and the second circulation part 75 b include a tubular part 76 in which a part of the circulation channel C is formed, and flanges 74 disposed at both ends of the tubular part 76. ,have. The tubular portion 76 can be freely changed in path such as a bellows-like tube or a tube formed of a flexible material.
The heat exchanging portion 85 is formed by, for example, a metal such as Fe, Cu, Al, or Mg, or a material that includes them and has excellent thermal conductivity. Preferably, only the surface in contact with the heat absorber 60 is made of the aforementioned material. In addition, the heat absorber 60 is preferably formed of the above-described material only on the surface in contact with the heat exchanging portion 85.
Furthermore, the heat exchange unit 85 and the heat absorber 60 may be provided with fins that increase the contact area between the liquid L and the refrigerant, respectively, and the contact area between the heat exchange unit 85 and the heat absorber 60 may be increased. In order to increase, for example, the contact surface may be formed in a wave shape.

As shown in FIG. 4, the circulation pump 80 and the heat exchange unit 85 are provided with a heat exchange unit 85 on the downstream side of the circulation pump 80. In addition, a first circulation part 75a is disposed between the mounting part 71 and the second circulation part 75b.
In addition, the number of the 1st circulation part 75a may be reduced as needed, or a thing with a long full length may be used. Further, as described above, the second circulation section 75b may be provided with two elements, the circulation pump 80 and the heat exchange section 85, or another element, for example, the heat of the liquid L is released to the outside. Radiating fins may be added, the same elements may be added to increase the number of elements, or the number of elements may be decreased.
Note that a liquid leakage prevention member 74a such as packing may be sandwiched between the mounting portion 71, the first circulation portion 75a, and the flange 74 of the second circulation portion 75b, If you can prevent leaks, you do n’t have to pinch anything,
Further, as described above, the circulation pump 80 and the heat exchange unit 85 may be provided in the first circulation unit 75a, and the circulation pump 80 and the heat exchange unit 85 are detachably attached to the circulation channel C, respectively. You may be comprised so that it may become.

  The liquid L is selected from liquids that are non-corrosive to the members provided in the light source device 70. More preferably, a liquid having a low vapor pressure, a low freezing point, excellent thermal stability, and high thermal conductivity is desired. Examples of liquids applicable to the present invention include organic liquid media such as biphenyl diphenyl ether, alkyl benzene, alkyl biphenyl, triaryl dimethane, alkyl naphthalene, hydrogenated terphenyl, and diaryl alkane. Can be mentioned. Silicone and fluorine liquids are also applicable. Among these, the light source device is selected in consideration of the application, required performance, environmental conservation and the like.

Next, the operation of the light source device 70 having the above configuration, particularly the cooling of the light source unit 20 will be described. Since the light emission from the light source unit 20 is the same as that of the first embodiment, the description thereof is omitted.
A part of the electric power supplied to the LED chip 21 is converted into heat, and the heat is transmitted from the LED chip 21 to the mounting plate 72 and taken away from the mounting plate 71 by the liquid L. The liquid L whose temperature has been removed due to heat removal is transported from the mounting portion 71 to the heat exchanging portion 85 by the circulation pump 80. The liquid L that has flowed into the heat exchanging portion 85 is deprived of heat by the low-temperature refrigerant flowing in the heat absorber 60, becomes the low-temperature liquid L, flows into the mounting portion 71 again, and deprives the LED chip 21 of heat. Cooling.

  In the heat absorber 60, the refrigerant evaporates by taking heat from the liquid L, becomes a gaseous refrigerant, is sucked into the compressor 30, and is pumped to the radiator 40 as a high-temperature and high-pressure refrigerant. In the radiator 40, the high-temperature and high-pressure refrigerant releases its heat (including the heat taken from the liquid L) to the surroundings and condenses to become a liquid refrigerant. The refrigerant that has become liquid is depressurized and expanded by flowing through the expansion valve 50, becomes a low-temperature and low-pressure refrigerant, flows again into the heat absorber 60, and absorbs the heat of the liquid L.

  According to said structure, since the circulation channel C through which the liquid L circulates is arrange | positioned between the LED chip 21 and the heat absorber 60, the channel through which a refrigerant circulates can be shortened. The flow path through which the refrigerant circulates includes a high-pressure region and a low-pressure region due to the compressor 30 and the expansion valve 50, and thus a configuration that can withstand the pressure difference from the surroundings is required. Then, since the thickness of the member which comprises a flow path etc. increases, size reduction of a light source device can be achieved by shortening the flow path through which a refrigerant circulates.

Increase the amount of heat transfer by using a material with high thermal conductivity for the heat exchanging portion 85 arranged in the second circulation portion 75b or by increasing the contact area between the heat exchanging portion 85 and the heat absorber 60. The cooling efficiency of the LED chip 21 can be improved.
In addition, by using a material having high thermal conductivity only for the contact surface between the heat exchanging portion 85 and the heat absorber 60, it is possible to prevent the refrigerant from depriving the surrounding heat, and the cooling efficiency of the liquid L, and thus A decrease in the cooling efficiency of the LED chip 21 can be prevented.

  As described above, the light source device may have a single light source unit and a set of compressors, radiators, expansion valves, and heat absorbers. As shown in FIG. The light source unit and a plurality of sets of compressors, radiators, expansion valves, and heat absorbers may be included, and the number is not particularly limited.

[Projection type display device]
FIG. 6 is an explanatory diagram of a projection display device 500 including the light source device according to the present embodiment. In the figure, reference numerals 512, 513, and 514 denote light source devices of the present embodiment, 522, 523, and 524 denote liquid crystal light valves (light modulation means), 525 denotes a cross dichroic prism (color light synthesis means), and 526 denotes a projection lens (projection means). ).

  The projection display device 500 of FIG. 6 includes three light source devices 512, 513, and 514 configured as in the present embodiment. Each of the light source devices 512, 513, and 514 employs LEDs that emit light in red (R), green (G), and blue (B). As a uniform illumination system for making the illuminance distribution of the light source light uniform, a rod lens or fly-eye lens may be arranged in front of each light source device.

  The light beam from the red light source device 512 passes through the superimposing lens 535R, is reflected by the reflection mirror 517, and enters the liquid crystal light valve 522 for red light. The light beam from the green light source device 513 passes through the superimposing lens 535G and enters the green light liquid crystal light valve 523. The light beam from the blue light source device 514 passes through the superimposing lens 535B, is reflected by the reflecting mirror 516, and enters the blue light liquid crystal light valve 524. The light flux from each light source is superimposed on the display area of the liquid crystal light valve through the superimposing lens so that the liquid crystal light valve is illuminated uniformly.

  In addition, polarizing plates (not shown) are arranged on the incident side and the emission side of each liquid crystal light valve. Then, only linearly polarized light in a predetermined direction out of the light flux from each light source passes through the incident side polarizing plate and enters each liquid crystal light valve. Further, a polarization conversion means (not shown) may be provided behind the incident side polarizing plate. In this case, it is possible to recycle the light beam reflected by the incident-side polarizing plate and make it incident on each liquid crystal light valve, thereby improving the light utilization efficiency.

  The three color lights modulated by the liquid crystal light valves 522, 523, and 524 are incident on the cross dichroic prism 525. This prism is formed by bonding four right-angle prisms, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are arranged in a cross shape on the inner surface thereof. These dielectric multilayer films combine the three color lights to form light representing a color image. The synthesized light is projected onto the projection screen 527 by the projection lens 526 which is a projection optical system, and an enlarged image is displayed.

  In the light source device of the present embodiment described above, the LEDs can be efficiently cooled, so that the input current can be increased to increase the brightness. Therefore, by providing the light source device described above, it is possible to provide a bright projector with excellent display quality.

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, in the present embodiment, an LED is used as the solid light source, but a semiconductor laser or the like may be used as the solid light source. In the present embodiment, the cooling fins are used as the cooling means, but a Peltier element or the like can also be used as the cooling means. Further, in the projector described above, a liquid crystal light valve is employed as the light modulation means, but a digital micromirror device (DMD, registered trademark) or the like may be employed as the light modulation means.

It is the schematic of the light source device which concerns on 1st Embodiment in this invention. It is the schematic of the light source device which concerns on the modification of 1st Embodiment. It is the schematic of the light source device which concerns on the modification of 1st Embodiment. It is the schematic of the light source device which concerns on 2nd Embodiment in this invention. It is the schematic of the light source device which concerns on the modification of 2nd Embodiment. It is a schematic block diagram of the projection type display apparatus using the light source device of this invention.

Explanation of symbols

10, 70, 512, 513, 514 ... Light source device, 21 ... LED chip (solid light source), 30 ... Compressor (compression means), 40 ... Radiator (heat dissipation means), ..Expansion valve (pressure reducing means), 60... Heat absorber (heat absorption means), 75 a... First circulation part (circulation part) 75 a, 75 b. ... Circulation pump (circulation means), 85 ... Heat exchange section (heat exchange means), 500 ... Projection type display device, 522, 523, 524 ... Liquid crystal light valve (light modulation means), 526 ... Projection lenses (projection means)

Claims (4)

A solid-state light source that emits light, a compression unit that compresses the refrigerant, a heat release unit that releases heat of the compressed refrigerant to the outside, a pressure reduction unit that depressurizes the released refrigerant, and an endotherm that causes the reduced pressure refrigerant to absorb heat Means,
The light source device, wherein the solid light source and the heat absorbing means are thermally connected. Between the solid light source and the heat absorption means, a circulation unit is disposed in which a liquid medium that transports heat generated from the solid light source circulates,
The light source device according to claim 1, wherein a circulation unit that circulates the liquid medium is disposed in the circulation unit.   3. The light source device according to claim 1, wherein a heat exchange unit that transmits heat of the liquid medium to the heat absorption unit is disposed in the circulation unit. A projection display device comprising: a light source device that emits light; a light modulation unit that modulates light from the light source device; and a projection unit that projects light modulated by the light modulation unit,
The projection type display device, wherein the light source device is the light source device according to claim 1.

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