JP2005085810A - Optical source unit and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state optical source which can be efficiently cooled down, and to provide an optical source unit which can be made simple in structure. <P>SOLUTION: The optical source unit is equipped with a solid-state optical source 21 mounted on a base stand 40, a first cooling medium 51 which is kept inside the base stand 40 so as to indirectly cool down the solid-state optical source 21, and a second cooling medium 52 that is arranged outside the base stand 40 so as to directly cool down the solid-state optical source 21. Particularly, the peripheral part of the first cooling medium 51 is preferably arranged outside the peripheral part of the mounting surface of the solid-state optical source 21. The first cooling medium 51 and/or the second cooling medium 52 can be circulated by a circulating means and cooled down by a cooling means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light source device and a projector.

  In recent years, projectors 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 a diagonal of 1.3 in to 0.5 in and an area ratio of 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.
JP-A-6-5923 JP-A-7-99372

  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 the LED 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 to solve the above-described problem, and an object of the present invention is to provide a light source device that can efficiently cool a solid-state light source and can simplify the structure. Furthermore, it aims at providing the projector which is bright and excellent in display quality.

To achieve the above object, a light source device according to the present invention includes a solid light source mounted on a base part, a first refrigerant that is disposed inside the base part and indirectly cools the solid light source, and the base And a second refrigerant that is arranged outside the unit and directly cools the solid-state light source.
According to this configuration, since the direct cooling method and the indirect cooling method are used together, it is possible to achieve both efficient cooling of the solid light source and simplification of the mounting structure of the solid light source.

The solid light source may be mounted on a mounting board of the base portion, and the first refrigerant may indirectly cool the solid light source via the mounting board.
According to this configuration, since the solid light source is mounted on the mounting substrate, the mounting structure of the solid light source can be simplified. Further, since the solid light source is indirectly cooled via the mounting substrate, the solid light source can be efficiently cooled.

In addition, it is preferable that a peripheral portion of the first refrigerant is disposed outside a peripheral portion of the mounting surface of the solid light source.
According to this configuration, since the projection area of the first refrigerant on the mounting surface of the solid light source is larger than the mounting area of the solid light source, the mounting surface of the solid light source can be efficiently cooled.

In addition, it is preferable that the distance from the peripheral edge of the mounting surface of the solid light source to the peripheral edge of the first refrigerant is greater than or equal to the distance from the solid light source to the first refrigerant.
According to this configuration, the projected area of the first refrigerant on the mounting surface of the solid light source becomes sufficiently large, and the distance from the solid light source to the first refrigerant can be compensated. Can be cooled.

In addition, it is preferable that the second refrigerant is in contact with a surface other than the mounting surface of the solid light source to directly cool the solid light source.
According to this configuration, the surface other than the mounting surface cooled by the first refrigerant can be cooled by the second refrigerant. Therefore, all surfaces of the solid light source can be efficiently cooled.

Moreover, it is desirable that the first refrigerant and / or the second refrigerant can be circulated by a circulation means.
According to this configuration, the first refrigerant and / or the second refrigerant can be continuously supplied, and the solid light source can be efficiently cooled.

The circulating means for circulating the first refrigerant and the circulating means for circulating the second refrigerant may be separately provided.
According to this configuration, different types of substances can be adopted for the first refrigerant and the second refrigerant, or the circulation speeds of the first refrigerant and the second refrigerant can be individually set. Therefore, the solid light source can be efficiently cooled.

Note that the first refrigerant and the second refrigerant may be connected to the common circulation means.
According to this configuration, the solid light source can be cooled by a single circulation means, and the structure of the light source device can be simplified and downsized.

In addition, it is desirable that the first refrigerant and / or the second refrigerant can be cooled by a cooling means.
According to this configuration, the low-temperature first refrigerant and / or the second refrigerant can be supplied, and the solid light source can be efficiently cooled.

On the other hand, a projector according to the present invention includes the light source device described above.
Since the above-described light source device can cool the solid light source efficiently, it is possible to increase the input current and increase the luminance. Therefore, by providing the light source device described above, it is possible to provide a bright projector with excellent display quality.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

ただし、λは熱媒体の熱伝導率、Ｓは低熱源の接触面積、Ｗは高熱源と低熱源との距離、θ２は高熱源の温度、θ１は低熱源の温度である。ここで、高熱源から低熱源に対して効率よく熱移動させる方法として、（１）低熱源の温度θ１を下げる方法、（２）熱伝導率λの大きい熱媒体を用いる方法、（３）高熱源と低熱源との距離Ｗを小さくする方法、（４）低熱源の面積Ｓを大きくする方法が考えられる。このうち（３）および（４）は、数式１のＳ／Ｗを大きくすることに一致する。 (High heat source cooling method)
First, a cooling method for a high heat source based on the law of heat conduction will be described with reference to FIGS. FIG. 6 is an explanatory diagram of the law of heat conduction, and FIG. 7 is an explanatory diagram of the cooling method of the high heat source.
As shown in FIG. 6, when the high heat source (heating element) is cooled by the low heat source (cooling means) through the heat medium, the heat transfer amount dQ per unit time from the high heat source to the low heat source is expressed by the following equation. Is done.

Where λ is the thermal conductivity of the heat medium, S is the contact area of the low heat source, W is the distance between the high heat source and the low heat source, θ2 is the temperature of the high heat source, and θ1 is the temperature of the low heat source. Here, as a method of efficiently transferring heat from a high heat source to a low heat source, (1) a method of lowering the temperature θ1 of the low heat source, (2) a method of using a heat medium having a large thermal conductivity λ, (3) high A method of reducing the distance W between the heat source and the low heat source, and (4) a method of increasing the area S of the low heat source are conceivable. Of these, (3) and (4) coincide with increasing the S / W of Equation 1.

  Therefore, even when a light emitting diode (LED) that is a high heat source is cooled by a refrigerant that is a low heat source, it is desirable to cool the light emitting diode (LED) so that the S / W of Formula 1 is small. As a specific method, a cooling method shown in FIGS. 7A to 7C can be considered. FIG. 7A shows a method in which the coolant 50 is brought into contact with the entire surface of the LED 21 and directly cooled. In this case, the S / W can be minimized. 7B, the flow path of the first refrigerant 51 is brought into contact with the lower surface of the LED 21, and the flow path of the second refrigerant 52 is brought into contact with the upper surface of the LED 21, so that the partition walls of the respective refrigerant flow paths are used as the heat medium. Thus, the LED 21 is indirectly cooled. This is a method of sandwiching the LED 21 from above and below with a low heat source, paying attention to the fact that the LED 21 is a flat plate. In this case, since each refrigerant | coolant 51 and 52 does not contact LED21 directly, the choice of a refrigerant | coolant increases. The applicant of the present application has applied for a patent on the light source device adopting the cooling method of FIGS. 7A and 7B.

  FIG. 7 (c) is a compromise between the direct cooling method of FIG. 7 (a) and the indirect cooling method of FIG. 7 (b). First, the 2nd refrigerant | coolant 52 which is a low heat source is made to contact the upper surface and side surface (exposed surface) of LED21 which is a high heat source, and it cools directly. In this case, since there is nothing corresponding to the heat medium, the distance W between the high heat source and the low heat source is zero. Moreover, the flow path of the 1st refrigerant | coolant 51 which is a low heat source is made to contact the lower surface (mounting surface) of LED21 which is a high heat source, and is indirectly cooled. Note that heat radiation from the side surface of the LED 21 can be efficiently absorbed by sufficiently increasing the area S of the first refrigerant flow path relative to the mounting area of the LED 21. 7C, the S / W can be increased as compared with the indirect cooling method of FIG. 7B, and the LED 21 can be compared with the direct cooling method of FIG. 7A. The mounting structure is simplified. The present application relates to an invention of a light source device adopting the cooling method of FIG.

[Light source device]
FIG. 1 is an explanatory diagram of a light source unit in the light source device of the present embodiment, and is a side cross-sectional view taken along the line AA of FIG. FIG. 2 is a plan view of the light source unit. The light source unit 20 in the light source device of the present embodiment includes a solid light source 21 mounted on the base unit 40, a first refrigerant 51 that is disposed inside the base unit 40 and indirectly cools the solid light source 21, and a base unit And a second refrigerant 52 that is disposed outside 40 and directly cools the solid-state light source 21. As shown in FIG. 4, the light source unit 20 described above, circulation pumps 56a and 56b for circulating the first refrigerant 51 and the second refrigerant 52, and cooling fins 57a for cooling the first refrigerant 51 and the second refrigerant 52, 57b, the light source device 10 of the present embodiment is configured. Furthermore, the projector 500 shown in FIG. 8 is configured by the light source device of the present embodiment including the solid light source that emits red light, green light, and blue light.

(Solid light source)
As shown in FIG. 1, a light emitting diode (LED) 21 is employed as a solid light source in the light source unit 20 in the light source device of the present embodiment. An LED is a diode that emits light when a current flows through a pn junction. In a homojunction type LED in which the same semiconductor material is joined, there is no barrier against carriers injected into the light emitting portion, so that the carriers spread to the diffusion distance in the semiconductor. On the other hand, in a heterojunction LED in which different semiconductor materials are joined, a barrier against carriers is created in the structure, so that the density of carriers injected into the light emitting portion can be greatly increased. In particular, in a double heterojunction LED in which a light emitting layer is sandwiched between cladding layers, the carrier density can be increased as the width of the light emitting layer is narrowed, and the internal quantum efficiency can be improved. On the other hand, in the homojunction type LED, the material in contact with the outside world and the material of the light emitting part are the same, and thus the light emission is absorbed by its own material. In contrast, in a double heterojunction type LED, a light emitting layer made of a material having a narrow band gap is sandwiched between clad layers made of a material having a wide band gap, so that self-absorption is reduced and light extraction efficiency is reduced. Can be improved. Therefore, it is desirable to employ a double heterojunction type LED having excellent luminous efficiency.

An LED that emits blue light and green light is formed by growing a GaInN-based compound semiconductor crystal on the surface of a substrate such as sapphire (Al ₂ O ₃ ). A double heterojunction structure in which a light emitting layer made of InGaN is sandwiched between a clad layer made of n-GaN and a clad layer made of p-GaN is adopted. The LED emitting red light is formed by growing an AlGaInP-based compound semiconductor crystal on a substrate such as gallium arsenide (GaAs). Since the GaAs substrate absorbs visible light, there is a limit to improving the light extraction efficiency of the LED. Therefore, it is desirable to remove the GaAs substrate after growing the semiconductor crystal and attach a gallium phosphide (GaP) substrate transparent to the emission wavelength at a high temperature and high pressure. Then, a double heterojunction structure is employed in which an AlGaInP light emitting layer is sandwiched between an n-GaP clad layer and a p-GaP clad layer.

  By the way, when a semiconductor crystal is grown on the surface of the electrically insulating substrate, an n-type electrode cannot be formed on the back surface of the substrate. Therefore, both electrodes of pn are formed on the growth surface of the semiconductor crystal. Specifically, a p-type electrode is formed on the surface of the p-type cladding layer, and an n-type electrode is formed on the surface of the n-type cladding layer that is exposed by etching away a part of the p-type cladding layer and the light emitting layer. Form. If the p-type electrode and / or the n-type electrode is made of a transparent material, light can be extracted from the electrode side, but light loss is unavoidable when passing through the electrode. Therefore, the p-type electrode and the n-type electrode are mounted on the base portion 40, and light is extracted from the transparent electrically insulating substrate. In this case, if the p-type electrode and the n-type electrode are made of a highly reflective metal material, the light extraction efficiency can be further improved.

(Base)
The base unit 40 mainly includes a mounting substrate 45 and a mounting surface cooling unit 46. The mounting substrate 45 is formed in a disk shape from an epoxy resin mixed with glass fiber. A pair of mounting terminals 41 is formed on the upper surface of the mounting substrate 45 by a conductive material such as Al or Cu. The p-type electrode and the n-type electrode of the LED 21 described above are connected to the pair of mounting terminals 41 by flip chip bonding or the like. Thus, by mounting the LED 21 on the mounting substrate 45, the mounting structure of the LED 21 can be simplified. Note that a gap between the LED 21 and the mounting substrate 45 is filled with an underfill 43 made of a resin material. In addition, lead terminals 42 extend from the mounting terminals 41 to the outside of the mounting substrate 45 so that the LEDs 21 can be energized from the outside of the light source unit 20.

A mounting surface cooling unit 46 is disposed on the lower surface of the mounting substrate 45. The mounting surface cooling unit 46 mainly cools the back surface (the mounting surface on the mounting substrate 45) of the LED 21 with the first refrigerant 51 disposed inside the first refrigerant flow path 31.
3A and 3B are explanatory views of the mounting surface cooling unit, in which FIG. 3A is a side cross-sectional view taken along the line AA in FIG. 2, and FIG. 3B is a BB line in FIG. FIG. The mounting surface cooling unit 46 mainly includes a base body 46a, a lid member 46b, and a first refrigerant 51. The base body 46 a and the lid member 46 b are made of a material having high thermal conductivity and having corrosion resistance against the first refrigerant 51. The flow path 31 of the first refrigerant 51 is formed by the groove formed on the upper surface of the base body 46a and the lid member 46b attached to the entire upper surface of the base body 46a. The width of the first coolant channel 31 is formed larger than the width of the LED at the center of the base body 46a, and gradually decreases toward the end of the base body 46a.

  Note that the mounting board described above may be used as the wall material of the first coolant channel 31 instead of the lid member 46b. In this case, since the solid light source is indirectly cooled only through the mounting substrate, the solid light source can be efficiently cooled. However, when the first refrigerant 51 is absorbed by the constituent material of the mounting substrate, a penetration preventing layer for the first refrigerant 51 is provided on the contact surface of the mounting substrate with the first refrigerant 51.

(First refrigerant)
A first refrigerant 51 is disposed inside the first refrigerant flow path 31. A liquid material having high thermal conductivity is employed as the first refrigerant. More preferred is a liquid material having electrical insulation, low vapor pressure, low freezing point, and excellent thermal stability. The first refrigerant may not be a transparent liquid material. Examples of liquids that can be used as the first refrigerant include biphenyl diphenyl ether, alkyl benzene, alkyl biphenyl, triaryl dimethane, alkyl naphthalene, hydrogenated terphenyl, and diaryl alkane. Can be mentioned. Silicone and fluorine-based liquids can also be used. From these substances, the first refrigerant may be selected in consideration of the use of the light source device, required performance, environmental conservation, and the like.

  As shown in FIG. 1, the mounting surface cooling unit 46 cools the LED 21, which is a high heat source, with the first refrigerant 51, which is a low heat source, via the lid member 46 b, the mounting substrate 45, and the underfill 43, which is a heat medium. To do. Therefore, if each member is designed so that S / W of Formula 1 is increased, the LED can be efficiently cooled. First, in order to reduce W, which is the distance between the high heat source and the low heat source, the thickness of the lid member 46b and the mounting substrate 45, which are heat media, may be reduced. As described above, it is also effective to eliminate the lid member 46 b and form the first coolant channel 31 by the mounting substrate 45. On the other hand, in order to increase S, which is the area of the low heat source, the peripheral portion of the first coolant channel 31 may be disposed outside the peripheral portion of the mounting surface of the LED 21. According to this configuration, since the projected area of the first refrigerant 51 on the mounting surface of the LED 21 is larger than the mounting area of the LED 21, the mounting surface of the LED 21 can be efficiently cooled. More preferably, the protruding length L from the peripheral edge of the mounting surface of the LED 21 to the peripheral edge of the first refrigerant channel 31 is set to be equal to or longer than the distance W from the LED 21 to the first refrigerant channel 31. By the projecting portion of the first refrigerant flow path 31, the projected area of the first refrigerant 51 on the mounting surface of the LED 21 becomes sufficiently larger than the mounting area of the LED 21, and the distance from the LED 21 to the first refrigerant can be compensated. Therefore, the mounting surface of the LED 21 can be efficiently cooled. Moreover, it becomes possible to cool the side surface of the LED 21 through a second refrigerant described later.

(Lighting part)
On the other hand, a light projecting unit 25 is formed on the upper surface of the base unit 40. The light projecting unit 25 mainly includes an LED 21, a reflecting mirror 26, a lens 27, and an exposed surface cooling unit 47 of the LED 21.
An annular reflecting mirror 26 is formed on the periphery of the upper surface of the mounting substrate 45. The reflecting mirror 26 reflects the light emitted from the LEDs 21 to the rear side (light irradiation direction by the light source device). Therefore, the inner surface 26a of the reflecting mirror 26 is a bank-like slope, and at least the inner surface 26a is in a mirror state. The lens 27 is formed so as to cover the entire top surface of the mounting substrate 45. The lens 27 condenses light emitted radially from the LED 21 backward. Therefore, the lens 27 is made of a transparent material such as an epoxy resin, and is a convex lens having a thicker central portion than a peripheral portion.

(Second refrigerant)
The LED 21 and its exposed surface cooling unit 47 are provided between the lens 27 and the mounting substrate 45. The exposed surface cooling section 47 mainly cools the upper surface and side surfaces (exposed surfaces other than the mounting surface) of the LED 21 by the second refrigerant 52 disposed inside the second refrigerant flow path 36. The second coolant channel 36 is formed by forming a groove on the bottom surface of the lens 27 and bonding the lens 27 to the top surface of the mounting substrate 45. As shown in FIG. 2, the width of the second coolant channel 36 is formed larger than the width of the LED 21 at the center of the lens 27, and gradually decreases toward the end of the lens 27. A second refrigerant 52 is disposed inside the second refrigerant flow path 36. The substance that can be used as the second refrigerant 52 is the same as the substance that can be used as the first refrigerant. However, since the light from the LED 21 is emitted through the second refrigerant 52, a transparent substance is used as the second refrigerant. Further, since the second refrigerant is in direct contact with the LED 21 and the lens 27, a substance that does not erode the constituent materials of the LED 21 and the lens 27 is employed as the second refrigerant.

  As shown in FIG. 1, the exposed surface cooling unit 47 directly cools the LED 21 that is a high heat source by using the second refrigerant 52 that is a low heat source without passing through a heat medium. In this case, the distance W between the high heat source and the low heat source in Equation 1 is zero. On the other hand, since the 2nd refrigerant | coolant 52 contacts the whole exposed surface of LED21, the contact area S of a low heat source becomes large. Therefore, S / W of Formula 1 becomes large, and the exposed surface of the LED can be efficiently cooled.

(Circulation means, cooling means)
FIG. 4 is a schematic diagram showing the overall configuration of the light source device of the present embodiment. The first refrigerant flow path 31 extending from both ends of the light source unit 20 is connected to a circulation pump 56a which is a circulation means for the first refrigerant 51, thereby forming a first refrigerant circulation path 55A. The first refrigerant circulation path 55A is provided with cooling fins 57a that are cooling means for the first refrigerant. The cooling fins 57 are constituted by a large number of fins (fins) made of a metal material having a high heat transfer coefficient such as Fe, Cu, Al, or Mg. Thereby, the surface area of the first refrigerant circulation path 55A is increased, and the heat dissipation capability to the outside is enhanced. If a ventilation means for forcibly ventilating the periphery of the cooling fin 57a is introduced, the heat dissipation capability of the cooling fin 57a can be further enhanced. Moreover, when the 1st refrigerant | coolant 51 is cooled by circulating through the 1st refrigerant | coolant circulation path 55A, it is not necessary to provide cooling means, such as the cooling fin 57a.
On the other hand, similarly to the above, the second refrigerant flow path 36 extending from both ends of the light source unit 20 is connected to the circulation pump 56b to form the second refrigerant circulation path 55B. The second refrigerant circulation path 55B is also provided with the same cooling fins 57b as described above.

  Thus, different types of substances can be adopted for the first refrigerant 51 and the second refrigerant 52 by separately forming the first refrigerant circulation path 55A and the second refrigerant circulation path 55B. For example, it is possible to select the first refrigerant 51 with an emphasis on high thermal conductivity and to select the second refrigerant 52 with an emphasis on safety with respect to the LED. Moreover, the circulation speed of the 1st refrigerant | coolant 51 and the 2nd refrigerant | coolant 52 can be set separately. For example, it is possible to average the cooling capacity by making the circulation speed of the first refrigerant 51 that is an indirect cooling system faster than the circulation speed of the second refrigerant 52 that is a direct cooling system. Thereby, the cooling capacity of LED can be improved.

  FIG. 5 is a schematic diagram illustrating a modification of the light source device of the present embodiment. In FIG. 5, the first refrigerant channel 31 and the second refrigerant channel 36 extending from the light source unit 20 are connected in series to one circulation pump 56 to form a common refrigerant circuit 55. . One cooling fin 57 is provided in the common refrigerant circulation path 55. In this case, it is possible to circulate the refrigerant in the first refrigerant flow path 31 and the second refrigerant flow path 36 with one circulation pump 56, and the first refrigerant flow path 31 and the first refrigerant flow path with one cooling fin 57. The refrigerant in the two refrigerant channels 36 can be cooled. Therefore, the structure of the light source device 10 can be simplified, and the manufacturing cost and operating cost of the light source device 10 can be reduced. Moreover, the light source device 10 can be reduced in size. Even when the first refrigerant flow path 31 and the second refrigerant flow path 36 are connected in parallel to one circulation pump 56, the same effect as described above can be obtained.

  As described in detail above, the light source device of the present embodiment has the mounting surface cooling unit 46 and the exposed surface cooling unit 47 shown in FIG. By this mounting surface cooling section 46, the mounting surface of the LED 21 can mainly be indirectly cooled efficiently. Moreover, the exposed surface cooling unit 47 can mainly cool the exposed surface of the LED 21 directly and efficiently. Therefore, the entire surface of the LED 21 can be efficiently cooled. Accordingly, the light emission efficiency of the LED 21 is improved, so that the input current to the LED 21 can be increased, and the brightness of the LED 21 can be increased. Moreover, even if the area of the LED chip is reduced to reduce the etendue, a high output can be maintained. On the other hand, since the indirect cooling method is adopted for the mounting surface cooling unit 46, the mounting structure of the LED 21 can be simplified, and the light source device can be reduced in size and cost.

[projector]
FIG. 8 is an explanatory diagram of a projector 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 combining means), and 526 denotes a projection lens (projection means). ).

  The projector shown in FIG. 8 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 behind 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.

  Further, 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 in front of 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.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. That is, the specific materials and configurations described in the embodiments are merely examples, and can be changed as appropriate. 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 side surface sectional drawing of the light source part in the light source device of embodiment. It is a top view of a light source part. It is explanatory drawing of the flow-path structure of a 2nd refrigerant | coolant. It is the schematic which shows the whole structure of the light source device of embodiment. It is the schematic which shows the modification of the light source device of embodiment. It is explanatory drawing of the law of heat conduction. It is explanatory drawing of the cooling system of a high heat source. It is explanatory drawing of the projector provided with the light source device which concerns on embodiment.

Explanation of symbols

  21 solid light source 40 base 51 first refrigerant 52 second refrigerant

Claims (10)

A solid state light source mounted on the base,
A first refrigerant that is disposed inside the base and indirectly cools the solid-state light source;
A second refrigerant disposed outside the base and directly cooling the solid light source;
A light source device comprising: The solid light source is mounted on a mounting substrate of the base part,
The light source device according to claim 1, wherein the first refrigerant indirectly cools the solid-state light source through the mounting substrate. 3. The light source device according to claim 1, wherein a peripheral portion of the first refrigerant is disposed outside a peripheral portion of the mounting surface of the solid-state light source. The distance from the peripheral part of the mounting surface of the said solid light source to the peripheral part of the said 1st refrigerant | coolant is formed so that it may become more than the distance from the said solid light source to the said 1st refrigerant | coolant. The light source device according to 1. 5. The light source device according to claim 1, wherein the second refrigerant contacts a surface other than a mounting surface of the solid light source to directly cool the solid light source. The light source device according to any one of claims 1 to 5, wherein the first refrigerant and / or the second refrigerant can be circulated by a circulation means. The light source apparatus according to claim 6, wherein the circulation unit that circulates the first refrigerant and the circulation unit that circulates the second refrigerant are separately provided. The light source device according to claim 6, wherein the first refrigerant and the second refrigerant are connected to the common circulation unit. The light source device according to claim 1, wherein the first refrigerant and / or the second refrigerant can be cooled by a cooling unit. A projector comprising the light source device according to claim 1.

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