HK1111027B - Projector and method for cooling the same - Google Patents

Description

Projector and cooling method thereof

Background

Technical Field

The present invention relates to a projector that projects an image based on a video signal.

Background

Many projectors are currently used to project images displayed on a personal computer screen and images of video signals on the screen, as well as images of image data stored on a memory card.

In many cases, this type of projector is arranged such that: using a small, high-luminance light source such as a metal halide lamp or an ultra-high pressure mercury lamp, light emitted from the light source is split into light beams of three primary colors by a color filter to be irradiated to imaging devices called liquid crystal or Digital Micromirror Devices (DMDs) through a light source side optical system, and then the light transmitted from the liquid crystal type imaging device or the light reflected from the DMD type imaging device is projected to a screen through a set of lens elements such as a projection side optical system having a zoom function.

In addition, in this type of projector, since the light source generates a large amount of heat or has a high heat generation amount, further, a light source side optical system, a power supply circuit, an image forming apparatus, and the like, which constitute a heat source, are included therein, and a cooling mechanism including a cooling fan is included in the projector so as to cool the light source apparatus, the power supply circuit, and the like, which constitute the heat source.

Such a cooling mechanism proposes a cooling system in which not only a light source which is particularly heated to a high temperature while generating a large amount of heat is separated from other heat sources as an independent part, but also an optical system, a power supply unit, and the like are separated from each other as independent parts so that each part is independently cooled (for example, refer to japanese unexamined patent publication No. 2004-054055).

Disclosure of Invention

However, in the conventional projector, since other heat sources such as a power supply circuit, an optical system on the light source side, DMDs functioning as an image forming device, and the like are incorporated therein in addition to the light source lamp heated to a high temperature and having a high heat generation amount, a plurality of cooling fans are provided to cool the light source lamp and the other heat sources, and therefore, there are disadvantages that the projector is difficult to be reduced in size and the fans generate noise.

The present invention is proposed to eliminate these drawbacks.

As a preferred aspect of the invention, there is provided a projector including: a light source disposed in the vicinity of an exhaust port of a cooling fan for blowing exhaust air toward the light source; a vent through which air blown toward the light source is discharged, and a heat source in the projector other than the light source as the heat source, which is cooled by an external air flow drawn in by drawing in the external air by the cooling fan.

In addition, as another preferred aspect of the invention, there is provided a projector including a light source device disposed in the vicinity of an exhaust port of a cooling fan, a vent through which air is discharged to the outside, which occurs after the air discharged from the cooling fan is blown toward the light source device, and a heat source present in the projector other than the light source, the heat source being cooled using an external air flow drawn in by the cooling fan as cooling air.

Further, another preferred aspect of the invention herein provides a method for cooling a projector, which includes providing a light source device in the vicinity of an exhaust port of a cooling fan, blowing air discharged from the cooling fan toward the light source device as cool air, directly discharging the air blown toward the light source device to the outside of the projector, and cooling a heat source in the projector other than the light source device by an outside air flow drawn in by the cooling fan.

According to the present invention, it is possible to achieve a reduction in the size of the projector and/or better cooling of the projector.

Drawings

Fig. 1 is an external view of a projector according to the invention;

fig. 2 is a circuit schematic diagram of a control block diagram of a projector according to the invention;

fig. 3 is a schematic view of a projector according to the invention with the top plate removed;

fig. 4 is a schematic view of a projector according to the invention in a state where a housing cover and a part of a partition plate of a lamp housing are removed;

fig. 5 is a schematic view of a projector according to the invention viewed from the rear thereof with its ceiling removed;

fig. 6 is a schematic view of a state when the projector according to the invention is horizontally cut at a height corresponding to a half height of the projector;

fig. 7 is a schematic view showing a partial cut-out of a main part of a projector according to the invention;

fig. 8 is a schematic diagram of a state after a top plate of a projector is removed according to another embodiment of the invention.

Detailed Description

In the projector 10 according to the present invention, the projection side optical system is provided along the side plate of the main casing, the imaging device 51 is provided near the rear back plate 13 in a coaxial manner with the optical axis of the projection side optical system, a gap is provided between the imaging device mounting plate 55 and the rear back plate 13 so as to form an air flow passage, and thus the heat dissipation plate 53 of the imaging device 51 is provided into the air flow passage thus formed. The light source device 61 is disposed inside the projection side optical system, and the partitions 121 and 122 made of a heat insulating material are disposed further inside than the light source device 61. Further, the cooling fan is disposed at a substantially central position of the projector 10, and the air outlet 113 of the cooling fan is disposed in the vicinity of the light source device 61 so that the air discharged from the cooling fan is blown toward the light source device 61 from between the two partitions 121, 122 made of a heat insulating material. Then, the air blown toward the light source device 61 is discharged from the front plate 12 of the main casing to the outside of the projector 10.

In addition, a control circuit board 103 functioning as a main circuit board of the projector 10 is provided near the cooling fan so that the outside air entering the cooling fan further passes through the control circuit board. Further, the power supply control circuit 41 is provided directly adjacent to the main casing or on the main circuit board, and part of the components constituting the light source side optical system are housed in a casing 131 made of a material that is good at heat transfer and fixed to the main casing such as the base plate 16.

As shown in fig. 1, the projector according to the embodiment of the invention is made in a substantially rectangular parallelepiped shape, and a lens cover 19 that covers the projector opening or lens is provided on the side of the front plate 12 constituting the main casing. In addition, a plurality of ventilation openings 18 are provided on the front panel 12.

In addition, although omitted in fig. 1, the projector 10 is also provided with a key/indication unit on the top plate 11 of the main casing, and provided on the key/indication unit are keys and indicators, including: a power ON/OFF switch; a power indicator that indicates whether power supply of the power source is on or off; a lamp on/off key for lighting the lamp of the light source device; a light indicator to indicate illumination of a light; and an overheat indicator which activates an alarm when the light source device or the like is overheated.

Further, on the rear side of the main housing, which is not shown, an input/output connector unit is provided, where a USB interface, a D-SUB interface for image signal input, an S interface, and an RCA interface are provided on the rear back plate, and an infrared (Ir) receiving unit is also provided.

Note also that a plurality of ventilation openings 18 are provided on each right side plate of the main casing, the right side plate is not shown, and the left side plate 15 is the side plate shown in fig. 1.

In addition, as shown in fig. 2, the control circuit of the projector 10 has, for example, a control unit 38, an input/output interface 22, an image conversion unit 23, a display encoder 24, a display drive unit 26, and the like. The image signals of the various standards input from the input/output connector unit 21 are transmitted to the image converting unit 23 through the input/output interface 22 and the System Bus (SB), where the image signals thus transmitted are converted and combined into image signals of a predetermined format suitable for display, and then transmitted to the display encoder 24.

In addition, the display encoder 24 decodes and stores the image signal sent thereto in the video RAM 25, generates a video signal in accordance with the content stored in the video RAM, and outputs the video signal thus generated to the display driving unit 26.

Next, with the display driving unit 26, the video signal from the display encoder 24 is input to drive the imaging device 51, which imaging device 51 is a spatial light modulator (SOM) at an appropriate frame rate according to the image signal sent therefrom. In addition, in this projector 10, by allowing light from the light source device 61 to be incident on the imaging device 51 via the light source side optical system, an optical image is formed by reflected light from the imaging device 51, and the image of the optical image is projection-displayed onto a screen (not shown) by a projection side lens element group constituting the projection side optical system. In addition, the movable lens element group 97 of the projection side lens element group is driven by the lens motor 45 for zoom adjustment and focus adjustment.

Further, the image compression/decompression unit 31 performs a recording process in which the luminance signal and the color-difference signal of the image signal are data-compressed by the ADTC and huffman encoding processes so as to be sequentially written onto the memory card 32, which is a removable re-encoding medium and in the reproduction mode, reads out the image data recorded in the memory card 32, decodes the respective image data of a series of moving pictures constituting one frame by one frame, and sends the thus-decoded image data to the display encoder 24 through the image conversion unit 23 so that the moving pictures and the like can be displayed based on the image data stored on the memory card 32.

The control unit 38 manages operation control of each circuit in the projector 10, and is constituted by a CPU, a ROM that fixedly stores operation programs for various types of settings, and a RAM that serves as a work memory.

In addition, an operation signal of a key/pointer unit 37 provided to the top plate 11 of the main casing and composed of a main key and a pointer is directly transmitted to the control unit 38, a key control signal from the remote controller is received by an infrared (Ir) receiving unit 35, demodulated into an encoded signal by an infrared processing unit 36, and a signal of this pattern is transmitted to the control unit 38.

Note that the control unit 38 is connected to the voice processing unit 47 through a System Bus (SB), and the voice processing unit 47 includes a sound source circuit of a PCM sound source, converts sound data into analog data in the projection mode and the reproduction mode, and drives the speaker 48 to emit sound loudly.

In addition, the control unit 38 controls the power supply control circuit 41 in such a manner that: when the on-off key of the lamp is operated, the lamp of the light source device 61 is turned on by the power supply control circuit 41. Further, the control unit 38 causes the cooling fan drive control circuit 43 to perform temperature detection by a temperature sensor provided on the light source device 61 so as to control the rotation speed of the cooling fan.

In addition, these RAM, ROM, IC and other circuit devices are mounted on a control circuit board 103 functioning as a main control circuit board, and a power supply control circuit 41 as a part of a power supply system is incorporated on a power supply circuit board 101 of a lamp, so that the control circuit board 103 as the control system main control circuit board and the power supply circuit board 101 of the lamp of the power supply system are formed separately from each other.

In addition, as shown in fig. 3 and 4, in the internal structure of the projector 10 in which the lamp power supply circuit board 101 incorporating the power supply control circuit 41 is disposed in the vicinity of the right side plate 14, a sirocco fan-type blower 110 is disposed as a cooling fan at substantially the center of the bottom plate 16. In addition, the outlet 113 of the blower 110 made to function as a cooling fan is fixed directly against the light source device 61 in which the light source bulb is incorporated, and the optical system on the projection side is disposed along the left side plate 15, and both the light source device 61 and the light source side optical system are disposed inside the optical system on the projection side.

As shown in fig. 6, the optical system of the projector 10 is constituted by a light source device 61 in which a discharge tube 63 is provided in the interior of a reflector 65, the reflector 65 whose front side is covered with an explosion-proof glass 68 as an ultra-high pressure mercury lamp, a light source side optical system constituting an imaging device 51, and a lens element group of the projection side optical system which shines light emitted from the light source device 61 onto a digital micromirror device constituting the imaging device 51, so as to form an image on a display screen.

Further, the light source side optical system is constituted by a color wheel 71, a light guide rod 75, a prism 77, a light source side lens element group 83, and a mirror 85, the color wheel 71 has a color filter on its periphery which decomposes light emitted from the light source device 61 into a red light column, a green light column, and a blue light column, and the color wheel 71 is driven by a wheel motor 73, the light guide rod 75 converts light beams from the color wheel 71 filter into light beams each having a uniform intensity distribution, the prism 77 changes the direction of the light beams emitted from the light guide rod 75 by 90 degrees, the light source side lens element group 83 is composed of a plurality of lens elements for converging light beams having passed through the prism 77 as combined light onto the imaging device 51, and the mirror 85 emits light having passed through the lens element group 83 onto the imaging device 51 at a predetermined angle.

Note that there may be a case where not an optical prism but a mirror is used for the prism 77, and the prism 77 is to be combined with the light guide bar 75.

Further, the optical system on the projection side is constituted by a variable focus lens which is in turn constituted by a fixed lens element group 93 incorporated into the fixed lens barrel 91 and a movable lens element group 97 incorporated into the movable lens barrel 95, and the movable lens element group 97 is moved by the lens motor 45 so as to enable zoom adjustment and focus adjustment.

In addition, the ventilation opening 18 is provided on the back panel 13 at a position coinciding with the rear of the image forming device 51, and an air flow path is formed by the back panel 13 and the image forming device mounting plate 55 so that outside air introduced thereto from the ventilation opening 18 provided in the back panel 13 and the ventilation opening 18 provided at the rear of the left side panel 15 flows in the direction of the blower 110.

As shown in fig. 4 and 5, the imaging device heat radiation plate 53 is provided behind the imaging device mounting plate 55, as shown in fig. 5, the control circuit board 103 is constituted by two control circuit boards, and air flowing between the two control circuit boards 103 and along the upper and lower sides of the two control circuit boards 103 is designed to flow into the suction port 111 of the blower fan 110.

Further, the light source side optical system and the light source device 61 are both accommodated in the lamp housing 120, and as shown in fig. 6, the lamp housing 120 is surrounded around its circumference by a first partition plate 121, a second partition plate 122, a third partition plate 123, a fourth partition plate 124, and as shown in fig. 3, is covered by a housing cover 125 at the top of the lamp housing 120, the first partition plate 121 extends from the discharge port 113 of the blower 110 to the front plate 112, the second partition plate 122 extends from the imaging device mounting plate 55 to the discharge port 113 of the blower 110, the third partition plate 123 extends through the lens barrel 81 for the light source side lens element group 83 so as to support the lens barrel 81, and the fourth partition plate 124 continues from the third partition plate 123 to the front plate 12 in such a manner as to partition the projection side optical system from the light source device 61.

Note that a sheet having heat insulating properties is used for the first partition 121 and the second partition 122, and the third partition 123 and the case cover 125, and a material having good heat conductivity such as an aluminum sheet is used for the fourth partition 124.

In addition, the discharge port 113 of the blower 110 is disposed near the light source device 61 while being directed to the slit provided between the first partition 121 and the second partition 122.

In addition, inside the lamp housing 120, a straightening plate 127 is provided close to the color wheel 71 in parallel with the color wheel for causing part of the air drawn into the lamp housing 120 from the discharge port 113 of the blower 110 to flow along the surface of the color wheel 71.

Further, the light guide rod 75 and the prism 77 are accommodated in a metal shell 131 made of a material having good heat conductivity and fixed to the base plate 16, and the metal shell 131 and the fourth spacer 124 are connected to each other by a metal rod 133.

Therefore, when the fan of the blower 110, which is a cooling fan, is rotated, air is drawn in the periphery thereof and thus outside air is drawn into the interior of the projector 10 from the plurality of ventilation openings 18 provided on the main casing of the projector 10 by drawing air remaining in the projector 10 around the blower 110.

The air sucked from the ventilation opening 18 in the rear of the left side plate 15 and the ventilation opening 18 in the rear back plate 13 passes through the airflow passage between the rear back plate 13 and the imaging device mounting plate 55 to cool the heat radiating plate 53 of the imaging device, and further passes above the upper side of the upper control circuit board 103 and below the lower side of the lower control circuit board 103, and passes through the space between these control circuit boards 103, to be sucked into the suction opening 111 of the blower fan 110.

In addition, a part of the outside air sucked from the ventilation opening 18 in the right side plate 14 into the interior of the projector 10 also passes around the lamp power supply circuit board 101 to the control circuit board 103, and further flows along the control circuit board 103, thereby being sucked from the suction opening 111 of the blower 110.

Note that the power supply control circuit 41 is incorporated not only on the lamp power supply circuit board 101 separate from the control system, but also on the control circuit board 103, the control circuit board 103 being a main circuit board.

The straightening plate 127 causes part of the exhaust air flow drawn into the lamp housing 120 to flow along the color wheel 71 and most of the exhaust air flow along the periphery of the light source device 61, as shown in fig. 6 and 7, and part of the air flows along the periphery of the light source device 61 in such a manner as to pass through the inside of the reflector 65 from the opening provided in the reflector 65 and cool the light source device 61 and the color wheel 71 at the same time, and is discharged outside the projector 10 from the ventilation opening 18 in the front plate 12.

Therefore, the light source device 61 is heated to the highest temperature inside the projector 10 and generates a large amount of heat, and since the light source device 61 is disposed near the discharge port of the blower 110, which functions as a cooling fan, a large amount of air can be blown toward the light source device 61, thereby making it possible to cool the light source device 61 and the color wheel 71 disposed directly adjacent to the light source device 61 in an efficient manner.

In addition, since the light source device 61 is disposed inside the lamp housing 120, the lamp housing 120 is surrounded by the first and second partitions 121 and 121, and the third partition 123, the fourth partition 124, and the housing cover 125, the air drawn into the lamp housing 120 is directly discharged from the vent 18 in the front plate 12 to the outside of the projector 10, and the first and second partitions 121 and 122, and the housing cover 125 are made of a sheet material having heat insulating properties, the heat discharged from the light source device 61 is never transmitted to other spaces inside the projector 10, thereby making it possible to effectively cool the projector 10.

In addition, heat from the light guide rod 75 and the prism 77 disposed inside the lamp housing 120 is dissipated not only through the metal shell 131 and the metal rod 133 but also through a large amount of air flowing in the lamp housing 120, whereby the light guide rod 75 and the prism 77 are cooled.

In addition, the imaging device heat dissipation plate 53 and the lamp power supply circuit board 101 are cooled by fresh outside air drawn into the projector 10 from the outside thereof, while the control circuit board 103 is cooled by a large amount of air drawn by the blower 110, and therefore, the heat source in the projector 10 can be effectively cooled by a single cooling fan, thereby making it possible to reduce the size of the projector 10.

Since the blower 110 made to function as a cooling fan is disposed near the center of the projector 10, the rotational noise of the fan is hard to leak, and thus the fan noise is reduced.

In addition, regarding the cooling of the imaging device heat dissipation plate 53, the efficiency on the imaging device heat dissipation plate 53 can be adjusted by the position, number, and size of the ventilation openings 18 provided in the rear plate 13 of the projector 10, and the gap between the imaging device mounting plate 55 and the rear plate 13.

The cooling of the lamp power supply circuit board 101 can also be adjusted by the position, number, and size of the ventilation openings 18 provided in the right side plate 14 of the projector 10, and the distance between the lamp power supply circuit board 101 and the right side plate 14.

In addition, the cooling efficiency of the control circuit boards 103 functioning as the main circuit board can be adjusted by adjusting the flow rate and the air speed and the distance from the suction port 111 of the blower 110, the number of the control circuit boards 103, and the distance between the respective control circuit boards 103.

Further, among the plurality of control circuit boards 103 stacked on each other at an interval, the control circuit board 103 disposed at the top is made larger than the other control circuit boards 103, so that the components fabricated at the top of the blower 110 functioning as a cooling fan can be covered by the control circuit board 103 disposed at the top.

In this case, the plurality of vents 105 are provided in the control circuit board 103 provided at the top of the plurality of control circuit boards 103 in such a manner as to coincide with the positions of the suction ports 111 of the blower 110.

Therefore, by making the control circuit board 103 disposed on the top of the plurality of control circuit boards 103 larger than the others, since the mounting of the plurality of control circuit boards is facilitated, and the plurality of ventilation openings 105 are disposed in a manner to coincide with the positions of the suction ports 111 of the blower 110, the air remaining in the projector 10 can be sucked into the blower 110 from the ventilation openings 105, so that the air remaining in the gap between the control circuit board disposed on the top and the main casing top plate 11 is sucked, so that the air existing on the upper surface of the control circuit board 103 disposed on the top is caused to flow.

Therefore, the speed and flow rate of the cooling air flowing along the upper and lower surfaces of each control circuit board 103 are controlled by adjusting the number, size and position of the vents 105, and adjusted by adjusting the gap between the control circuit board 103 covering the upper surface of the blower 110 and the upper surface of the blower 110, thereby making it possible to adjust and set the cooling degree of the plurality of circuit devices constituting the heat source.

Note that the cooling fan is not limited to the sirocco fan type blower 110.

Further, it is also noted that the present invention is not limited to the above-described embodiments, but may be freely modified and improved without departing from the spirit and scope of the invention.

Claims (19)

1. A projector, comprising:

a cooling fan disposed at a substantially central position of the projector main casing and having a suction port that sucks air from above;

a control circuit board arranged above the suction port; and

a light source device disposed near the exhaust port of the cooling fan,

it is characterized in that the preparation method is characterized in that,

air from multiple directions around the cooling fan within the projector main body is drawn from above the suction port along the control circuit board to cool multiple heat sources around the cooling fan except for the light source device, an

The air discharged through the air outlet is blown toward the light source device, and the air blown toward the light source device is then discharged to the outside of the projector main case through the air vent.

2. The projector as claimed in claim 1, wherein a vent for exhausting air is provided on a side of the projector housing.

3. The projector as claimed in claim 1, comprising a vent provided on the projector housing for drawing outside air into the housing.

4. A projector according to claim 3, wherein the ventilation openings for sucking in the outside air are provided on a plurality of sides of the projector housing.

5. The projector as claimed in claim 3, wherein the ventilation opening for taking in outside air and the ventilation opening for exhausting air are provided on mutually different sides of the projector housing.

6. A projector as claimed in claim 1, wherein the heat source other than the light source comprises an imaging device which forms an image to be projected.

7. A projector as claimed in claim 1, wherein the heat source other than the light source comprises a power supply for the light source.

8. The projector as claimed in claim 1, wherein the heat source other than the light source includes a control circuit board of the projector.

9. The projector as claimed in claim 1, further comprising a partition that spatially separates the light source and the heat source other than the light source.

10. The projector of claim 1 further comprising a projection lens and a baffle that spatially separates the light source from the projection lens.

11. The projector as claimed in claim 1, wherein the suction port and the discharge port of the cooling fan intersect each other at a right angle.

12. A projector, comprising:

a cooling fan disposed at a substantially central position of the projector main casing and having a suction port that sucks air from above;

a control circuit board arranged above the suction port;

a light source device disposed near the exhaust port of the cooling fan;

a vent through which air is discharged to the outside, which occurs after the air discharged from the cooling fan is blown toward the light source device; and

a heat source other than the light source, which is present in the projector, is cooled with an external air flow as cooling air from a plurality of directions surrounding the cooling fan within the projector main casing and taken in along the control circuit board by the cooling fan.

13. The projector as claimed in claim 12, wherein the main circuit board to which the control circuit board of the projector is incorporated is constituted by a plurality of circuit boards which are laminated on each other at a pitch and are disposed in the vicinity of the suction port of the cooling fan.

14. A projector according to claim 12, wherein the image forming device is provided inside the projector in the vicinity of the main casing, wherein an air flow passage is formed by a gap between the image forming device mounting plate and the main casing, and wherein a heat dissipation plate of the image forming device is provided in the air flow passage thus formed.

15. A projector according to claim 12, wherein a lamp housing is provided inside the projector, wherein the light source device is accommodated in the lamp housing, wherein exhaust air from the cooling fan is blown into the lamp housing while air remaining in the lamp housing is directly exhausted to the outside of the projector.

16. The projector as claimed in claim 12, wherein a part of the wall surface of the lamp housing is formed by a partition made of a heat insulating material.

17. The projector as claimed in claim 12, wherein a light source side optical system such as a light guide bar, a prism or a mirror as a heat source other than the light source device is fixed by a material having good heat conductivity.

18. The projector as claimed in claim 12, wherein the ventilation opening is provided on a portion of the main circuit board, and the main circuit board is provided near a suction port of the cooling fan.

19. A method of cooling a projector, comprising:

a cooling fan having an intake port for sucking air from above is disposed at a substantially central position of the projector main casing;

arranging the control circuit board to be positioned above the suction inlet;

a light source device is arranged near the exhaust port of the cooling fan;

blowing air discharged from the cooling fan toward the light source device as cooling air;

directly discharging air blown toward the light source device to the outside of the projector; and

heat sources other than the light source device present in the projector are cooled by an external air flow which is air from a plurality of directions surrounding the cooling fan within the projector main casing and which is drawn into a suction port of the cooling fan along the control circuit board.