CN100590516C - projection device - Google Patents

Abstract

A projection device comprises an illumination system, a reflective light valve, an imaging system, a loop type heat pipe and a radiator. The illumination system is adapted to provide an illumination beam, the reflective light valve is disposed in a transmission path of the illumination beam to convert the illumination beam into an image, and the imaging system is disposed in a transmission path of the image. The loop heat pipe includes an evaporation portion, a capillary structure, at least one conduit and a working fluid. The evaporation part is provided with a liquid backflow end and a gas discharge end, and the outer surface of the evaporation part is contacted with the reflection type light valve. The capillary structure is located in the evaporation part and communicated with the liquid return end. The conduit connects the liquid return end and the gas discharge end of the evaporation section. The working fluid is located in the conduit and the capillary structure.

Description

projection device

technical field

The present invention relates to a projection apparatus, and in particular to a projection apparatus with an optimal heat dissipation effect.

Background technique

Please refer to Fig. 1, a traditional digital light processing projection apparatus (Digital light processing projection apparatus) 100 includes an illumination system (illumination system) 110, a digital micromirror device (Digital Micro-mirror Device, DMD) 120 and an imaging system (imagingsystem) )130. The illumination system 110 has a light source 112 adapted to provide an illumination beam 114 . The DMD 120 is disposed on the transmission path of the illumination beam 114 and is suitable for converting the illumination beam 114 into an image beam 122 . In addition, the imaging system 130 is disposed on the transmission path of the image beam 122 to project the image beam 122 on a screen (not shown).

As the required wattage of the light source 112 increases, the operating temperature of the DMD 120 also increases. Since the digital micromirror device 120 operates at high temperature, there will be problems such as shortened component life and a decrease in the overall display quality of the digital light source processing projection device 100. Therefore, how to reduce the operating temperature of the digital micromirror device 120 has become one of the key points of active research and development. one.

In the traditional digital light source processing projection device 100, a high-speed fan is used in conjunction with a cooling fin design to dissipate the heat accumulated in the digital micromirror device 120, so as to avoid overheating of the digital micromirror device 120. . The thermal resistance caused by the heat dissipation design of high-speed fans and heat sinks is between 2°C/W and 5°C/W. To achieve lower thermal resistance, a large number of fins must be used. As a result, the overall cooling module is too bulky. When the heat to be dissipated gradually increases (that is, the heat density increases), simply using a high-speed fan with cooling fins cannot achieve the required cooling effect. At this time, it is necessary to use a high-speed fan with a heat pipe (heat pipe) To dissipate heat from the DMD 120 . The heat pipe will be described in detail below with reference to FIG. 2 .

Fig. 2 is a schematic diagram of a conventional heat pipe. Please refer to FIG. 2 , the conventional heat pipe 200 has an evaporation end 210 , a condensation end 220 , a capillary structure 230 and a working fluid 240 . One end of the heat pipe 200 is an evaporation end 210 , and the other end is a condensation end 220 . The capillary structure 230 is disposed on the inner pipe wall of the heat pipe 200 , and the working fluid 240 is located in the heat pipe 200 . Wherein, the evaporating end 210 is attached to the back of the DMD 120 to transmit the heat Q generated by the DMD 120, and the condensing end 220 is connected to the radiator 250, and the radiator 250 will be driven by a high rotating speed. The forced convection caused by the fan achieves the purpose of cooling. When the heat Q generated by the digital micromirror device 120 is transferred to the evaporation part 210 of the heat pipe 200, the working fluid 240 at the evaporation end 210 will absorb the heat Q and evaporate into a vapor 240'. At this time, the vapor will move toward the condensation end. 220 flow. When the steam flows to the condensing end 220 , the steam will condense into a liquid state. At this time, the heat released by the condensation of the steam will be transferred from the condensing end 220 to the radiator. The liquid working fluid 240 generated at the condensing end 220 is sent back to the evaporating end 210 through the capillary structure 230 , so that the working fluid 240 can be repeatedly vaporized (the evaporating portion 210 ) and then condensed (the condensing end 220 ).

It can be seen from FIG. 2 that since the capillary structure 230 is located on most of the inner tube wall of the heat pipe 200, after the heat pipe 200 is bent or flattened, the capillary structure 230 will be destroyed, so that the working fluid 240 at the condensation end 220 The heat cannot be effectively sent back to the evaporating end 210 , thereby affecting the overall heat dissipation performance of the heat pipe 200 . In addition, when the condensing end 220 of the heat pipe 200 is located below the evaporating end 210, the water vapor generated at the evaporating end 210 is not easy to flow down to the condensing end 220, and the working fluid 240 generated at the condensing end 220 is not easy to flow along. The direction of anti-gravity is transmitted in the capillary structure 230 so that the working fluid 240 cannot be effectively transported back to the evaporation end 210 . Since the heat dissipation of each heat pipe is limited, multiple heat pipes are usually required in a heat dissipation module with a large wattage.

In addition to the above-mentioned heat dissipation design, conventional technology can also use liquid cooling to reduce the temperature of the DMD 120 . Generally speaking, the heat dissipation design of the liquid cooling method has a thermal resistance of about 0.3°C/W to 0.5°C/W. In this heat dissipation design, the life of the pump driving the working fluid circulation is limited, and the heat dissipation design needs to be equipped with a liquid storage tank to maintain the amount of working fluid, so the cost is relatively high.

Taking the projection device 100 with an output power of 8000 lumens (lumen) as an example, the heat Q generated by the lighting system 110 irradiating the digital micromirror device 120 (0.7-inch chip) is about 50 watts (Watt). The temperature of the micromirror array on the DMD 120 is lower than 65°C, and the temperature of the substrate of the DMD 120 must be lower than 45°C. Assuming that the operating environment temperature of the projection device 100 is between 25° C. and 35° C., the thermal resistance of the cooling module for dissipating heat from the DMD 120 must be lower than 0.2° C./W in order to make the DMD 120 The substrate temperature is below 45°C. To achieve such a low thermal resistance (less than 0.2° C./W), many heat pipes 200 must be used simultaneously. However, it is difficult to arrange multiple heat pipes 200 on the back of the DMD 120 at the same time.

Contents of the invention

The object of the present invention is to provide a projection device with good heat dissipation performance.

To achieve the above or other objects, the present invention proposes a projection device, which includes an illumination system, a reflective light valve, an imaging system, a loop heat pipe (loop heatpipe) and a radiator ( heat sink). The illumination system is adapted to provide an illumination beam, the reflective light valve is arranged on the transmission path of the illumination beam, and the reflection light valve is adapted to convert the illumination beam into an image, and the imaging system is arranged on the transmission path of the image. The loop heat pipe includes an evaporation part, a capillary structure, at least one conduit and working fluid. The evaporation part has a liquid return end and a gas discharge end, and the outer surface of the evaporation part is in contact with the reflective light valve. The capillary structure is located in the evaporation part and communicates with the liquid return port. The conduit connects the liquid return end and the gas discharge end of the evaporation part. The working fluid resides in the conduits and capillaries.

Since the present invention uses a loop heat pipe with low thermal resistance to dissipate heat from the reflective light valve, the heat accumulated in the reflective light valve can be absorbed to reduce the operating temperature of the reflective light valve. In addition, since the conduit in the loop heat pipe of the present invention can be bent arbitrarily, the present invention can fully match the space design of the projection device, and can be matched with different types of radiators to achieve optimal heat dissipation effects.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, preferred embodiments are described below in detail with accompanying drawings.

Description of drawings

FIG. 1 is a schematic diagram of a conventional digital light source processing projection device.

Fig. 2 is a schematic diagram of a conventional heat pipe.

FIG. 3 is a schematic diagram of a projection device according to the present invention.

FIG. 4 is an enlarged schematic view of the loop heat pipe and the reflective light valve in FIG. 3 .

Fig. 5 is a schematic cross-sectional view of the loop heat pipe along I-I' in Fig. 4 .

FIG. 6 is a schematic diagram of another projection device according to the present invention.

7 to 9 are schematic diagrams of different types of catheters in this embodiment.

10 and 11 are perspective views of collocation of different types of radiators and loop heat pipes.

12 is a schematic cross-sectional view of the assembly of the evaporating portion and the cooling fins.

Explanation of main component symbols

100: Digital light source processing projection device

110: Lighting system

112: light source

114: Lighting Beam

120: Digital Micromirror Device

122: image beam

130: Imaging system

200: heat pipe

210: Evaporation end

220: condensation end

230: capillary structure

240: working fluid

240': water vapor

300, 300': digital light source processing projection device

310: Lighting system

312: Lighting Beam

320: reflective light valve

322: Image

330: Imaging system

340: loop heat pipe

342, 342': Conduit

342a: Liquid return port

342b: gas discharge port

342c: Condenser

344: Working fluid

344': steam

346, 346': capillary structure

348, 348': evaporation department

348a: Outer surface

350: Radiator

350': cooling plate

350": cooling fins

360: Thermoelectric Cooling Chip

362: cold end

364: hot end

370, 380: sub-ducts

390: cooling fan

395: cooling fins

Q: heat

S: inner space

Detailed ways

FIG. 3 is a schematic diagram of a projection device according to the present invention. Please refer to FIG. 3 , the projection device 300 of this embodiment includes an illumination system 310 , a reflective light valve 320 , an imaging system 330 , a loop heat pipe 340 and a radiator 350 . The illumination system 310 is adapted to provide an illumination beam 312 , the reflective light valve 320 is disposed on the transmission path of the illumination beam 312 , and the reflective light valve 320 is adapted to transform the illumination beam 312 into an image 322 . The imaging system 330 is disposed on the transmission path of the image 322 to project the image 322 onto a screen (not shown). The detailed structure of the loop heat pipe 340 will be described later.

FIG. 4 is an enlarged schematic view of the loop heat pipe and the reflective light valve in FIG. 3 , and FIG. 5 is a schematic cross-sectional view of the loop heat pipe along I-I' in FIG. 4 . Please refer to FIG. 4 and FIG. 5 at the same time. The loop heat pipe 340 of this embodiment includes an evaporator 348 , a capillary structure 346 , at least one conduit 342 (only one conduit is shown in FIG. 4 ) and a working fluid 344 . Wherein, the evaporation portion 348 has a liquid return end 342 a and a gas discharge end 342 b, and the outer surface 348 a of the evaporation portion 348 is suitable for contacting the reflective light valve 320 . The capillary structure 346 is located in the evaporation part 348 and communicates with the liquid return port 342a. The conduit 342 connects the liquid return end 342a and the gas discharge end 342b, and has a condenser 342c. As can be seen from FIG. Working fluid 344 is located in conduit 342 and capillary structure 346 .

Please continue to refer to FIG. 4, since the outer surface 348a of the evaporator 348 is in contact with the reflective light valve 320, the heat Q accumulated in the reflective light valve 320 will be transferred to the evaporator 348 through the contacted outer surface 348a. The capillary structure 346 , at this time, the working fluid 344 penetrating into the capillary structure 346 absorbs the heat Q, and is vaporized into the vapor 344 ′ in the inner space S of the evaporation part 348 . The vapor 344' generated in the internal space S increases the vapor pressure in the internal space S and the conduit 342, and facilitates the flow of the working fluid 344 in the conduit 342. In the loop heat pipe 340, the driving force for the flow of the working fluid 344 mainly comes from the rise of the vapor pressure brought by the steam 344' and the traction of the working fluid 344 by the capillary structure 346 (capillary phenomenon). Under the circumstances, the heat dissipation efficiency of the loop heat pipe 340 in this embodiment will not be affected by gravity, so any orientation can be adopted according to the requirement.

The working fluid 344 flowing in the conduit 342 will flow into the evaporation part 348 from the liquid return end 342 a. After the working fluid 344 is vaporized, the steam 344' will flow from the gas discharge end 342b to the conduit 342, and when the steam 344' flows in the conduit 342 for a certain distance, the steam 344' will transfer heat Q to the conduit 342. The condensing part 342c and the heat sink 350 will condense into the working fluid 344 . Therefore, the condensed working fluid 344 can continuously dissipate heat from the reflective light valve 320 .

The size of the reflective light valve 320 can be any size digital micromirror device or single crystal silicon liquid crystal light valve. Generally speaking, if the size of the reflective light valve 320 is small (for example, 0.7 inches, 0.55 inches or smaller), the thermal resistance of the cooling module must be very low, so that the small-sized reflective light valve 320 can be effectively used. The accumulated heat Q in the light valve 320 is discharged. In the loop heat pipe 340 of this embodiment, the thermal resistance from the reflective light valve 320 to the evaporator 348 is only about 0.1°C/W, and the thermal resistance from the reflective light valve 320 to the external environment is only 0.2°C/W. W or so. Therefore, the loop heat pipe 340 of this embodiment has sufficient capacity to dissipate heat from the reflective light valve 320 . In addition, the size and shape of the evaporation part 348 can be designed in accordance with the size and shape of the reflective light valve 320, so that the evaporation part 348 can completely contact with the back of the reflective light valve 320, and further reduce the reflection from the reflective light valve. 320 to the thermal resistance of the evaporation section 348.

Based on the above, the vaporization temperature of the working fluid 344 is, for example, between 20° C. and 60° C., and in a preferred embodiment of the present invention, the working fluid 344 is, for example, water or other easily vaporized liquid.

FIG. 6 is a schematic diagram of another projection device according to the present invention. Referring to FIG. 6 , the projection device 300' further includes a thermoelectric cooling chip 360 disposed between the reflective light valve 320 and the loop heat pipe 340. The thermoelectric cooling chip 360 has a cold end 362 and a hot end 364. Wherein, the cold end 362 of the thermoelectric cooling chip 360 is in contact with the back of the reflective light valve 320 , and the loop heat pipe 340 is attached to the hot end 364 of the thermoelectric cooling chip 360 .

If it is desired to match the design of the condenser with a large heat dissipation area, the length of the conduit 342 can be changed so that it can be evenly distributed on the radiator 350, and the probability of heat exchange between the steam 344' and the external environment in the condensation part 342c will increase, so The vapor 344 ′ flowing in the conduit 342 can be completely converted into the working fluid 344 . Different types of conduits 342 will be described below.

7 to 9 are schematic diagrams of different types of catheters in this embodiment. Please refer to FIG. 7 first, in order to increase the contact area between the conduit 342' and the radiator 350, the conduit 342' can be bent arbitrarily so that it has multiple turning points B. At this time, the heat Q of the vapor 344' in the conduit 342' can be efficiently transferred to the radiator 350 through the conduit 342', and then dissipated to the external environment. In addition, in this embodiment, a heat dissipation fan 390 can also be used to dissipate heat from the radiator 350 , and in this case, the loop heat pipe 340 will have better heat dissipation performance.

Next, please refer to FIG. 8 . In addition to adopting a conduit 342' (shown in FIG. 7 ) with a turning point B, the present invention can also design the conduit 342 into other types. For example, the conduit 342 of the present invention may include a plurality of sub-conduits 370 (as shown in FIG. 8 ) communicating with each other, and the working fluid 344 flowing in each sub-conduit 370 will converge before entering the liquid return port 342a. , and then flow into the liquid return end 342a in the evaporation part 348 . After the working fluid 344 is vaporized, the steam 344' will be divided into different sub-pipes 370 by the single gas discharge end 342b of the evaporation part 348, so that the steam 344' in each sub-pipe 370 can simultaneously dissipate its The carried heat Q is transferred to the heat sink 350 .

Please refer to FIG. 9 , the conduit 342 of the present invention may also include a plurality of sub-conduits 380 (as shown in FIG. 9 ) that are not communicated with each other, and the working fluid 344 flowing in each sub-conduit 380 will flow from the liquid return port 342a respectively. Flow into the evaporator 348. After the working fluid 344 is vaporized, the steam 344' will flow from different gas discharge ends 342b into different sub-conduits 380, so that the steam 344' in each sub-conduit 380 can simultaneously transfer the heat Q Passed to the radiator 350.

Based on the above, the conduits 342, 342' described in Fig. 4, Fig. 7, Fig. 8 and Fig. 9 may be conduits made entirely of copper conduits, aluminum conduits or materials with high thermal conductivity, and in order to increase the assembly flexibility , also can only adopt copper conduit, aluminum conduit or the conduit of high thermal conductivity at the place that conduit contacts with radiator 350, the conduit of other part can adopt flexible pipe (as plastic flexible pipe or other flexible material is made) hose).

10 and 11 are perspective views of collocation of different types of radiators and loop heat pipes. The above-mentioned loop heat pipe 340 can be matched with a cooling plate 350' (as shown in FIG. 10 ), or a cooling fin 350 "(as shown in FIG. 11 ). Both the cooling plate 350' and the cooling fin 350 "are borrowed The heat Q is quickly transferred to the external environment through a large area.

12 is a schematic cross-sectional view of the assembly of the evaporator and the cooling fins. Please refer to FIG. In other words, the heat Q can be directly dissipated to the environment through the heat dissipation fins 395 on the outer surface 348a.

In summary, the projection device of the present invention has at least the following advantages:

1. The loop heat pipe used in the present invention has relatively low thermal resistance (less than 0.2°C/W), which can effectively reduce the operating temperature of the reflective light valve.

2. In the loop heat pipe used in the present invention, the pipe can be bent arbitrarily without damaging the capillary structure, so as to fully match the spatial design of the projection device.

3. In the loop heat pipe used in the present invention, its thermal resistance will not be greatly increased due to the increase in the length of the conduit.

4. The loop heat pipe used in the present invention can be placed in any way, and its heat dissipation performance is not affected by gravity.

5. The loop heat pipe used in the present invention is suitable for high heat density and has good heat dissipation performance.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall prevail as defined in the claims.

Claims (15)

1. A projection device comprising an illumination system, a reflective light valve, an imaging system, a loop heat pipe and a radiator, wherein: the lighting system is adapted to provide an illumination beam; The reflective light valve is disposed on the transmission path of the illumination beam and is suitable for converting the illumination beam into an image; The imaging system is configured on the transmission path of the image; The loop heat pipe includes an evaporation part, a capillary structure, at least one conduit and a working fluid, wherein: The evaporation part has a liquid return end and a gas discharge end, and the outer surface of the evaporation part is adapted to be in contact with the reflective light valve; The capillary structure is located in the evaporation part and communicated with the liquid return end; The conduit connects the liquid return end and the gas discharge end, and has a condensation part; the working fluid is located in the conduit and the capillary structure, The radiator is connected with the condensation part of the conduit. 2. The projection device according to claim 1, wherein the reflective light valve comprises a digital micromirror device or a single crystal silicon liquid crystal light valve. 3. The projection device according to claim 1, wherein the conduit has a plurality of turning points. 4. The projection device according to claim 1, wherein the duct comprises a plurality of sub-ducts communicating with each other. 5. The projection device according to claim 1, wherein the conduit comprises a plurality of sub-conduits not communicating with each other. 6. The projection apparatus according to claim 1, wherein the conduit comprises a copper conduit or an aluminum conduit. 7. The projection device according to claim 1, wherein the conduit comprises a plurality of hard tubes and at least one flexible tube connected between the hard tubes. 8. The projection device according to claim 1, wherein the vaporization temperature of the working fluid is between 20°C and 60°C. 9. The projection device according to claim 1, wherein the working fluid comprises water. 10. The projection device according to claim 1, wherein a material of the evaporation portion comprises copper or aluminum. 11. The projection device according to claim 1, wherein the evaporation part has an inner space, and the working fluid permeated in the capillary structure flows from the inner space to the gas discharge end after being vaporized. 12. The projection device according to claim 1, wherein the evaporating portion has a cooling fin on its outer surface. 13. The projection device according to claim 1, wherein the heat sink comprises heat dissipation fins or heat dissipation plates. 14. The projection device according to claim 1, further comprising a thermoelectric cooling chip disposed between the reflective light valve and the loop heat pipe. 15. The projection device according to claim 1, further comprising a cooling fan disposed on the radiator.

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