KR100800201B1 - Projection system - Google Patents

Abstract

The present invention relates to a projection system, and more particularly, to a projection system having a streamlined cooling path for cooling the inside of a lamp assembly in which a high temperature is generated, so that the inside of the lamp assembly can be cooled quickly and efficiently and stably operated. It is about.

Projection system according to the present invention for achieving the object as described above, the light is generated; A lamp case accommodating the lamp and having an air inlet formed on one side and an air outlet formed on the other side thereof; And a guide part for guiding the air flow so that air introduced into the lamp case through the air inlet is quickly discharged.

By the above configuration, there is an effect that the interior of the lamp assembly and the optical engine is cooled quickly and efficiently.

Projection, cooling

Description

Projection system. {Projection system}

1 is a cross-sectional view schematically showing a projection system according to the present invention.

2 is an external perspective view of an optical engine according to the present invention;

3 is a partially exploded perspective view of the optical engine;

Figure 4 is an exploded perspective view showing the optical engine coupled to the base according to the invention.

5 is an exploded perspective view of the optical engine.

6 is a perspective view of a lamp case of the optical engine according to the present invention;

7 is a sectional view taken along line II ′ of FIG. 6.

8 is a cross-sectional view of an optical engine for explaining the air flow of the cooling system of the optical engine according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1: projection system 10: optical engine unit

12: DMD fan 141: lamp cooling fan

20: optical engine 21: lamp assembly

22: color wheel assembly 23: light tunnel housing

24: light tunnel assembly 25: condensing lens

26: DMD Assembly 27: Actuator

28: reflector case 29: folding mirror

30: total reflection prism 31: projection lens assembly

43: color wheel cooling fan

The present invention relates to a projection system, and in particular, provided with a streamlined cooling passage for cooling the inside of a lamp assembly in which high temperature is generated, so that the interior of the lamp assembly and the optical engine can be cooled quickly and efficiently and stably operated. To a projection system.

Recently, large-screen high-definition display devices have emerged as a major topic, and such large-screen high-definition display devices include CRT (Cathode Ray Tube) televisions, Liquid Crystal Display (LCD) televisions, Projection televisions, and Plasma Display Panel (PDP) televisions. It's coming out.

Among them, the demand for the projection television and the development of technology are actively made as one of the display apparatuses that satisfy the requirements of large screen high definition. The projection television includes a liquid crystal on silicon (LCOS) method using an LCD and a digital light porsessing (DLP) method using a digital micromirror device (DMD).

Recently, low-cost projection TVs using LCDs or DMDs have been in the spotlight. In particular, as the consumer's desire for high quality along with a large screen increases, the demand is increasing year by year, and the trend is particularly popular in the digital television market currently being trial broadcast.

In addition, as the use of computers and presentations using computers have been increasing in recent years, the use of projectors using LCDs or DMDs has also increased.

In general, a projection television adopts a method in which light generated by an optical engine mounted inside a cabinet is reflected and an image is projected on a screen.

In detail, an optical engine using a DMD includes a lamp that emits white light, a color wheel device that separates light emitted from the lamp into red, green, and blue light, an illumination system that collects light passing through the color wheel device; And a DMD for receiving a light passing through the illumination system to create a desired screen, and a projection lens to enlarge and project the image generated from the DMD onto the screen.

The illumination system, the DMD, and the projection lens of the general projection system may be collectively referred to as an optical engine, and the optical engine is a part where high heat is generated by illumination light generated from a lamp. Therefore, in order to allow such high heat to be cooled, it is important to provide an appropriate cooling system and to prevent foreign matter from entering during cooling. If the high heat is not cooled, a problem may occur that a plurality of films provided in the illumination system and a DMD provided in the synthesis system are oxidized, and furthermore, a problem that the projection system does not operate normally may occur.

In such conventional projection systems, the lamp assembly and the interior of the optical engine are generally cooled by the air entering the air inlet of the fully opened lamp assembly. In addition, the conventional lamp assembly has a shape that is not suitable for guiding the flow of air flowing into the lamp, and a separate to cool the internal heat accumulated in the lamp assembly while reducing the flow resistance of the air The component was not included.

However, due to the decrease in DMD panel size (0.5 inch-> 0.45 inch) and consequent increase in lamp brightness (120 watts-> 132 watts) the temperature rise inside the optical engine makes it difficult to increase cooling efficiency with existing cooling systems. I lost. That is, as the place where the flow of air does not exist in the interior of the lamp case, there is a problem that the remaining heat is generated and the inside of the lamp assembly is not completely cooled, so that efficient cooling is not achieved.

Moreover, as the user's standards for noise become stricter, the reference value for noise generated inside the projection system has changed (30dB-> 25dB), so even at lower flow rates with low noise fans must be used. The structural modification of the lamp assembly was urgently required to achieve high cooling efficiency.

The present invention has been proposed to solve the above problems, by providing a streamlined cooling passage that can guide the flow of air inside the lamp casing, thereby providing a projection system in which the lamp assembly is cooled quickly and efficiently. It is for the purpose of suggestion.

It is also an object of the present invention to propose a projection system in which the flow rate of air flowing inside the lamp case is increased, the flow resistance and cooling loss are reduced, and the amount of heat remaining inside the lamp case is reduced.

In addition, a rapid and efficient cooling structure is provided to enable the use of low noise fans, and to provide a projection system that can satisfy the consumer's noise standards.

It is also an object of the present invention to propose a projection system in which the operation of the device can be stably performed even when the optical engine is used for a long time.

Projection system according to the present invention for achieving the object as described above, the light is generated; A lamp reflector for reflecting light from the lamp and condensing at a predetermined distance; A lamp case accommodating the lamp and having an air inlet formed on one side and an air outlet formed on the other side thereof; And a guide unit for guiding the air flow so that the air introduced into the lamp case through the air inlet quickly discharged; Is included, the air flowing into the inside of the lamp case through the air inlet flows in a direction to hit the outer surface of the lamp reflector corresponding to the opposite side of the lamp, a portion of the air hitting the lamp reflector is the lamp reflector Flow along the space between the guide portion and the remaining portion is characterized in that flowing into the lamp reflector.

By the above configuration, there is an effect that the interior of the lamp assembly and the optical engine is cooled quickly and efficiently.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the spirit of the present invention is not limited to the embodiments presented, and other embodiments included within the scope of other inventive inventions or the scope of the present invention can be easily added by adding, changing, or deleting other elements. I can suggest.

1 is a cross-sectional view schematically showing a projection system according to the spirit of the present invention.

Referring to FIG. 1, a projection system 1 according to the present invention includes a cabinet 2 forming an appearance, a screen 4 mounted on the front surface of the cabinet 2, and an optical seat mounted on a lower end of the cabinet 2. An engine unit 10 and a rearview mirror 3 mounted to the inner circumferential surface of the cabinet 2 to reflect the image emitted from the optical engine unit 10 onto the screen 4 are included.

In detail, the image screen formed and projected by the optical engine unit 10 is reflected by the rearview mirror 3. The reflected image is extended and projected onto the screen 4 so that the image screen is recognized by the user.

Hereinafter, the structure and function of each part of the optical engine unit 10 will be described in more detail with reference to the accompanying drawings.

2 is an external perspective view of an optical engine according to the inventive concept, and FIG. 3 is a partially exploded perspective view of the optical engine.

2 and 3, the optical engine unit 10 according to the present invention includes a base 11, an optical engine 20 mounted on the base 11, and an outer portion of the optical engine 20. Various parts to be mounted are included.

In detail, a power supply unit 15 for supplying an appropriate amount of power to various electrical components constituting the optical engine unit 10 may be provided to various components mounted on the outside of the optical engine 20, and the power supply unit 15. A power supply supporter 16 for supporting the lamp, a lamp cooling fan assembly 14 for cooling a lamp (to be described later) constituting the optical engine 20, and a ballast 13 mounted to one side of the base 11. ), A projection lens cap 17 surrounding the projection lens (to be described later) constituting the optical engine 20, and a DMD fan 12 for cooling the DMD (to be described later) constituting the optical engine 20. ) Is included.

In more detail, the power supply unit 15 is a switching mode power supply (SMPS), and is a modular power supply unit that converts electricity supplied from the outside to match the electric device. In addition, the power supply unit 15 controls the intermittent control at a high frequency of a commercial frequency or higher and mitigates the impact by using semiconductor switching characteristics.

In addition, the ballast 13 functions to apply a high voltage when the lamp constituting the optical engine 20 is turned on and to appropriately adjust the current so that an overcurrent does not flow after the lamp is turned on.

In addition, the lamp cooling fan assembly 14 includes a lamp cooling fan 141 for cooling the heat generated from the lamp.

As shown in FIG. 3, in the case of the optical engine unit 10 according to the present invention, each part except the optical engine 20 may be independently separated from the base 11. Thus, the optical engine 20 is mounted to the base 11, and then each of the components mentioned above are coupled to the base 11.

4 is an exploded perspective view illustrating a state in which an optical engine according to the spirit of the present invention is coupled to a base, and FIG. 5 is an exploded perspective view of the optical engine.

Referring to FIG. 4, the optical engine 20 for making an image screen in the optical engine unit 10 according to the present invention may be integrally separated from the base 11.

In detail, the optical engine 20 assembly is completely separated by removing only eight fastening members that allow the optical engine 20 assembly to be fixed to the base 11. Therefore, there is an advantage that the service is easily made and the disassembly and assembly process is very simple.

In addition, in order for the optical engine 20 assembly to be secured to the base 11, it is not necessary to first have the components of the optical engine 20 assembled to the base 11. That is, the optical engine 20 is assembled separately, and then integrally mounted on the base 11.

Referring to FIG. 5, the optical engine 20 according to the present invention includes a lamp assembly 21 in which white light is generated by a high voltage supplied by the ballast 13, and unpolarized light emitted from the lamp assembly 21. A color wheel assembly 22 for separating the red, green, and blue, a light tunnel assembly 24 for uniformly making red, green, and blue separated light while passing through the color wheel assembly 22; A light tunnel housing 23 in which the color wheel assembly 22 and the light tunnel assembly 24 are accommodated therein, and a condensing lens 25 in which uniform light is collected while passing through the light tunnel assembly 24. A folding mirror 29 for reflecting light passing through the condensing lens 25, a total reflection prism 30 for reflecting light reflected by the folding mirror 29 again, and total reflection By prism (30) DMD assembly 26 for reflecting light gathers to form image information, an actuator 27 for doubling the number of pixels of light reflected from the DMD assembly 26, and the actuator 27 A projection lens 31 for enlarging the light passing through is included. Here, the lamp assembly 21 is called a lamp system. The assembly of the color wheel assembly 22, the light tunnel assembly 24, and the condensing lens 25 is called an illumination system. The aggregate of the folding mirror 29 and the total reflection prism 30 is called a reflectometer, and the aggregate of the reflectometer and the DMD assembly 26 is called a synthetic system.

In more detail, the lamp assembly 21 includes a lamp 212 that emits white light and a lamp case 211 that protects the lamp 212. In addition, the reflector of the lamp 212 serves to change the light emitted from the burner of the lamp is reflected to focus at a certain distance, that is, the focal length.

In addition, a lamp cooling fan duct 42 and a lamp cooling fan 141 are formed on the front surface of the lamp case 211 to cool the heat generated by the lamp 212. That is, the lamp cooling fan duct 42 and the lamp cooling fan 141 serve as air flow path guides so that air passing through the lamp assembly 21 and the light tunnel housing 23 is discharged to the outside of the optical engine 20. Do it.

On the other hand, the color wheel assembly (22) is divided into red (Green), green (Green), blue (Blue) is divided into a color wheel (also called 221: RGB color filter) that rotates at high speed, and the color A motor 223 driving the wheel 221 and a heat dissipation fin 222 for cooling the motor 223.

In detail, light emitted from the lamp 212 by the reflector of the lamp 212 is focused on the surface of the color wheel 221. In addition, the light collected by the color wheel 221 passes through the color wheel 221 and has any color of red, blue, and green. Here, the color wheel 221 has a disk shape having a predetermined diameter, the disk is divided into red, green, blue. Accordingly, the unpolarized light reflected by the reflector has one of red, blue, and green colors due to the color of the color wheel 221 positioned at the time of condensing.

In addition, the color wheel assembly 22 and the light tunnel assembly 24 are housed inside the light tunnel housing 23. In addition, a color wheel cooling fan 43 is coupled to the rear of the light tunnel housing 23 so that the color wheel 221 rotating at a high speed is cooled.

In addition, the light tunnel assembly 24 is also called a rod lens, and serves to uniformly make colored light passing through the color wheel 221.

In detail, the light tunnel assembly 24 is formed by joining four small, long rectangular bar mirrors facing each other. Light passing through the color wheel assembly 22 is diffusely reflected while passing through the light tunnel, and the brightness distribution is uniform.

In addition, the condensing lens 25 performs a function of collecting red, green, and blue light uniformed while passing through the light tunnel assembly 24 to the DMD elements constituting the DMD assembly 26. do.

The total reflection prism 30 may also be referred to as a total internal reflection (TIR) prism, and a prism having a large refractive index and a prism having a relatively small refractive index are bonded to each other. And, due to the difference in refractive index is totally reflected or transmitted according to the incident angle of the light irradiated from the condensing lens 25.

In detail, each object has its own refractive index, and the difference in refractive index determines the critical angle at which light is totally reflected or transmitted.

Therefore, light incident at an angle greater than or equal to a critical angle is totally reflected by the total reflection prism 30, and light incident at an angle smaller than or equal to a critical angle passes through the total reflection prism 30.

In addition, the DMD assembly (Digital Micro-mirror Device Assembly) 26 is composed of a DMD panel and a driver board that accommodates the DMD panel. In detail, the driver board is a device for controlling the driving of the ballast and the color wheel or controlling the image.

On the other hand, the DMD panel is designed such that the same amount of fine mirrors as the resolution of the display is arranged so as to have a one-to-one correspondence with the screen.

In detail, the DMD panel determines whether the red, green, and blue light transmitted through the total reflection prism 30 is emitted toward the screen or discarded out of the screen. The DMD panel is mounted in a complementary metal oxide semiconductor (CMOS) memory and driven by a signal transmitted from the CMOS memory.

In more detail, the micromirror constituting the DMD panel is manufactured in the form of a fine diamond-shaped pixel having a width and width of 16 μm, and tilted by ± 10 degrees according to a signal transmitted from the CMOS, thereby reducing the total reflection prism 30. Passing light is either reflected off the screen or thrown out of the screen.

In addition, the actuator 27 is disposed between the DMD panel and the projection lens 31, and a mirror is mounted at the center portion. In detail, the actuator 27 functions to double the number of pixels of the image signal by refracting and dividing the image signal emitted from the DMD panel by half a frame. Due to the refraction characteristics of the mirror, the resolution of the screen is increased. In addition, the actuator includes a transmission type and a reflection type.

In addition, the projection lens assembly 31 functions to enlarge the image passing through the actuator 27 toward the rearview mirror 3. Details of the projection lens assembly 31 will be described in detail with reference to the accompanying drawings.

In the optical engine 20 having the above-described configuration, the actuator 27, the total reflection prism 30, and the folding mirror 29 are inserted from different surfaces of the reflector case 28 so that one reflectometer may be used. Configure. The color wheel assembly 22 and the light tunnel assembly 24 are accommodated in the light tunnel housing 23 to form another assembly. In addition, the lamp assembly 21 forms a separate assembly together with the lamp 212 mounted inside the lamp case 211, and the light tunnel housing 23 is in close contact with the front of the lamp assembly 21. do.

As described above, since a plurality of parts form a single assembly, there is an advantage that parts replacement and service are easily performed.

In the following, each configuration applied to the projection system according to the present invention, in particular the cooling system of the optical engine 20, will be briefly described.

First, the optical engine 20 guides the flow of air by the three fans 12, 141, 43 and the fans 12, 141, 43 to force the air to flow. A plurality of guide structures are formed for the purpose of describing the cooling system of the optical engine 20 based on the flow order of air.

First, cold air introduced into the projection system 1 from the outside is introduced into the optical engine 20, in particular, the DMD fan 12 on the side of the synthesis system, whereby heat generated from the synthesis system can be cooled. .

In addition, a lamp cooling fan 141 is formed in front of the lamp assembly 21 to cool the lamp 212. The lamp cooling fan 141 is discharged to the front of the projection system 1 after the air near the power supply 15 is introduced into the lamp assembly 21 to be discharged to the outside of the projection system.

Meanwhile, in order to cool the color wheel 221 rotating at a high speed, a color wheel cooling fan 43 is formed at the rear of the light tunnel housing 23. The color wheel cooling fan 43 flows into the light tunnel housing 23 after the air near the power supply unit 15 enters the light tunnel housing 23, and then cools the light tunnel housing 23, and then discharges it toward the front of the projection system 1. Be sure to

As can be seen from the above structure, the DMD fan 12, the lamp cooling fan 141 and the color wheel cooling fan 43 is seated in an adjacent position where the heat source is placed to provide a suction force, so that cold air is used to After passing through the structure to absorb the heat and sucked into the fan 12, 141, 43 is discharged.

Hereinafter, the configuration of the lamp assembly of the projection system according to the present invention will be described in detail.

6 is a perspective view of a lamp case of the optical engine according to the present invention, and FIG. 7 is a sectional view taken along line II ′ of FIG. 6.

6 and 7, the lamp case 211 of the projection system according to the present invention includes a lamp accommodating part 213 formed to accommodate the lamp 212 in the lamp case 211 and the lamp ( A cooling passage 214 formed inside the lamp receiving portion 213 is included to resemble the shape of 212.

In detail, the lamp case 211 that is accommodated inside the lamp 212 to protect the lamp 212 from external impact, the hollow box shape so that the lamp 212 is inserted therein can be accommodated Is done. In addition, a hollow housing part inside the lamp case 211 is formed with a lamp receiving part 213 in which the lamp 212 is accommodated. In addition, an air inlet 219 through which air flows into the lamp case 211 is formed at one side of the outer surface of the lamp case 211. In addition, an air discharge port is formed at the other side of the air suction port 219 to discharge the air sucked into the air suction port 219.

Meanwhile, a cooling passage 214 is formed at one side of the lamp case 211 to guide the flow of air flowing into the lamp case 211. Preferably, the cooling passage 214 is formed to be curved or inclined at a predetermined curvature so as to have a shape similar to the outer circumferential surface of the lamp 212.

In other words, in the related art, a portion in which the air is accumulated in the lamp case 211 is not smoothly flowed. Therefore, only heat around the lamp 212 is generated and residual heat is generated in the lamp case 211 spaced apart from the lamp to some extent. Efficient cooling is not achieved by the residual heat as described above, and there is a problem that air flow resistance occurs.

However, in the present invention, the cooling flow path 214 having a radius of curvature similar to the outer circumferential surface of the lamp 212 is provided to guide the smooth flow of air, thereby reducing the pressure drop generated during the flow of air, Increasingly, the cooling efficiency is maximized. In addition, it is possible to simultaneously cool the lamp and the lamp case at a limited flow rate, and there is an advantage that the amount of residual heat remaining inside the lamp case is reduced. Further, by enabling the efficient cooling by the above structure, there is an effect that the noise is reduced due to the use of a low noise fan.

8 is a cross-sectional view of an optical engine for explaining the air flow of the cooling system of the optical engine according to the present invention.

First, the driving force of the air flow for cooling the lamp 212 in which high heat is generated is provided by a lamp cooling fan (see 141 of FIG. 5) formed at one side of the lamp assembly 21. In other words, the lamp cooling fan 141 provides a suction force to suck air, so that the air at the rear of the lamp assembly 21 is discharged forward through the interior of the lamp assembly 21, thereby, the lamp assembly (21) The inside is cooled efficiently.

Referring to FIG. 8, air at the rear of the lamp assembly 21 is introduced into the lamp assembly 21 by suction force provided by the lamp cooling fan 141. Some of the air introduced into the lamp assembly 21 as described above is introduced into the lamp 212, and absorbs the heat emitted from the lamp 212 while flowing along the lamp 212, the lamp cooling fan Passed through the duct 42 and the lamp cooling fan 141 is discharged to the outside of the lamp assembly 21.

Meanwhile, some of the air introduced into the lamp assembly 21 flows along the outer circumferential surface of the lamp 212 and the cooling passage 214 formed in the lamp case 211. In addition, the air flowing in the lamp case 211 absorbs the heat emitted from the lamp 212 and is then discharged to the outside of the lamp assembly 21. At this time, the cooling passage 214 serves to increase the cooling efficiency in the lamp case 211 by allowing the air to flow in a predetermined direction.

Preferably, the cooling passage 214 is formed to maximize the flow rate of the air flowing in the lamp case 211, so that the introduced air is cooled after the entire outer peripheral surface of the lamp 212 is discharged. By the formation of the cooling passage 215 as described above, the air flow inside the lamp case 211 is made smoothly and efficiently, so that the flow rate of the flowed air increases, the flow resistance and the cooling loss are reduced, and the lamp case The amount of heat remaining inside 211 is reduced, and noise is reduced.

On the other hand, in a plurality of components provided to the optical engine 20, high heat is generated by the light generated by the lamp 212, such high heat is to be quickly discharged to the outside for the normal operation of the device There is a need. If the high heat generated during the operation of the device is not discharged to the outside, there is a problem that the matching of the image may be distorted due to the expansion of the parts, and the problem of oxidizing the DMD panel and various films may occur.

To this end, in the present invention, cooling is performed by the air sucked into the fan. Hereinafter, the cooling system of the projection system that solves this problem will be described in detail.

The cooling system of the present invention is divided into three parts, a first cooling system mainly for cooling the synthesis system, a second cooling system for cooling the lamp 212 in which high heat is directly generated, and a color wheel 221 rotating at high speed. A third cooling system for cooling) is included.

First, the first cooling system is a cooling system operated by the DMD fan 12, in which cool air outside the projection system 1 flows into the DMD fan 12 on the side of the synthesis system, thereby generating from the synthesis system. The hot air being cooled can be cooled.

In other words, the cooling system by the DMD fan 12 is configured to allow the sound pressure provided from the DMD fan 12 to be transmitted to the synthesis system. In addition, the sound pressure generated in the DMD fan 12 may be transmitted to the synthesis system and may be transmitted to other components near the DMD fan 12 to be cooled.

On the other hand, the second cooling system according to the present invention is a system operated by the lamp cooling fan 141 placed in front of the lamp assembly 21, the lamp cooling fan 141 is located near the power supply 15 After the air flows into the lamp 212 side and absorbs the high heat of the lamp 212, the lamp cooling fan duct 42 and the lamp cooling fan 141 formed on the front surface of the lamp assembly 21 may be used. Allow to be discharged to the outside. As a result, the lamp 212 in which high heat is generated can be cooled quickly and efficiently.

Meanwhile, the third cooling system according to the present invention is a system operated by the color wheel cooling fan 43 formed at the rear of the light tunnel housing 23 so that the color wheel 221 rotating at high speed is cooled. to be. The color wheel cooling fan 43 flows into the light tunnel housing 23 after the air near the power supply unit 15 enters the light tunnel housing 23, and then cools the light tunnel housing 23, and then discharges it toward the front of the projection system 1. Be sure to

As can be seen from the above structure, the first, second and third cooling systems are seated adjacent to where the heat source is placed to provide suction, so that cold air is absorbed by the fan as it passes through the heat source and is then drawn into the fan and discharged. It consists of a structure to make it possible. Since the air sucked by such a suction type cooling system can stably flow in the form of laminar flow when flowing into a high temperature part, for example, a color wheel, it is possible to obtain the advantage that the high temperature part increases the cooling efficiency. . In addition, since foreign matters are not lifted by the air flowing into the high-temperature parts, it is possible to obtain an advantage of preventing contamination by foreign matters.

By the cooling system according to the present invention it is possible to obtain an advantage that the cooling efficiency is improved while reducing the contamination of the projection system, in particular the optical engine.

According to the present invention, a streamlined cooling passage through which air flow can be guided is provided in the lamp case, and thus, the inside of the lamp assembly is cooled quickly and efficiently.

In addition, there is an effect that the flow rate of air flowing inside the lamp case is increased, flow resistance and cooling loss are reduced, and the amount of heat remaining inside the lamp case is reduced.

In addition, by providing a quick and efficient cooling structure to enable the use of low noise fans, there is an effect that can satisfy the consumer's noise standards.

In addition, even if the optical engine is used for a long time there is an advantage that the operation of the device can be performed stably.

Claims (5)

A lamp in which light is generated; A lamp reflector for reflecting light from the lamp and condensing at a predetermined distance; A lamp case accommodating the lamp and having an air inlet formed on one side and an air outlet formed on the other side thereof; And A guide unit for guiding the air flow so that air introduced into the lamp case through the air inlet is quickly discharged; Is included, Air introduced into the lamp case through the air inlet flows in a direction that strikes an outer surface of the lamp reflector corresponding to the opposite side of the lamp, and a part of the air that hits the lamp reflector is between the lamp reflector and the guide part. The projection system, characterized in that flows along the space of the remaining portion flows into the interior of the lamp reflector. The method of claim 1, And the guide part extends from the air inlet and is curved or inclined at a predetermined curvature while maintaining a predetermined distance from the lamp. The method of claim 1, And the guide part is spaced apart from an edge of the lamp case to prevent air sucked into the lamp case from hovering at an edge portion. The method of claim 1, And the guide part is curved or inclined in a direction in which a width thereof becomes wider from the air inlet to the air outlet. The method of claim 1, And the air inlet and the air outlet are formed at positions opposite to each other.

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