JP4175327B2 - Projector device - Google Patents

Description

  The present invention relates to a projector device that magnifies and projects a television image on a screen, and more particularly to a technique for cooling exhaust heat from the inside of the device.

  In recent years, with the enlargement of the display screen of a television receiver, a projection television (hereinafter abbreviated as a projector) that can enjoy a large screen image by projecting a television image on the screen has been reduced in size. Due to the improvement in luminance, it has been attracting attention and demand is increasing.

  In order to improve the brightness of the projector, it is necessary to increase the brightness of the lamp as a light source as much as possible. However, increasing the brightness of the lamp involves a large amount of power consumption and a large amount of heat, so cooling the lamp is indispensable. The temperature of the entire optical system including the lamp is lowered by a cooling fan, etc. It is essential for safety to keep the temperature below a certain temperature. Therefore, conventionally, various cooling measures have been taken such as using a cooling fan or a Peltier element using the Peltier effect in the projector.

  In this type of equipment, the hot air after cooling by the blower fan is sent to the outside of the equipment for the purpose of reducing the influence of light leaked from the light source lamp on an unspecified number of viewers and the hot air and noise from the cooling exhaust fan. A device is known in which a discharge port for discharging is arranged in parallel with a projection lens on the front surface of an apparatus exterior case (see, for example, Patent Document 1).

  However, in the projector device in the above-described conventional example, the exhaust port for discharging hot air and the projection lens are arranged side by side on the front surface of the device outer case, so that the hot air discharged from the exhaust port is used for the projection light from the projection lens. There is a problem in that the heat wave flows into the optical path and the projected image on the screen fluctuates (heat wave) due to the influence of the hot air.

  The mechanism of the occurrence of fluctuation on the projected image will be described with reference to FIG. In the projector device 101, light from a lamp 104 serving as a light source is incident on a casting engine 107 via a condensing optical system (not shown) such as an infrared filter (not shown) or a light tunnel, and reflected mirror. The light is reflected at 108 and is incident on a DMD (digital micromirror device) 109 whose reflection angle changes at the level of the video signal, and the light reflected by the DMD 109 is enlarged and projected on the screen by the projection lens 105.

  Then, the cooling air that has flowed into the apparatus main body 102 from the vent 111 and the vent 112 provided on the right side and the rear side of the exterior case 103 of the projector 101 in the drawing is supplied to the lamp 104 by the blower fan 106. Sent to the periphery of A part of the hot air after the cooling of the lamp 104 is discharged from the exhaust port 110 provided in the front surface of the exterior case 103 to the outside of the apparatus, and the projection light 120 by the projection lens 105 is projected as indicated by an arrow C. It flows into the optical path. For this reason, the light near the exhaust port 110 of the projection light 120 is affected by the hot air exhausted from the exhaust port 110, so that the projected image on the screen fluctuates.

  As another conventional example, a cooling device including a heat pipe, a Peltier element, and an axial fan is provided in an optical device of a liquid crystal projector, and heat generated by the liquid crystal projector is absorbed by the Peltier element through the heat pipe. At the same time, there is a projector device that cools the optical device by moving the heat of the liquid crystal projector to the Peltier device through a heat pipe by cooling the Peltier device with an axial fan and cooling the optical device (for example, , See Patent Document 2). However, since a separate cooling device such as a heat pipe, Peltier element and axial fan is required, the structure becomes complicated and the cost increases, and the cooling air from the Peltier element is for cooling the optical device. In addition, since it does not act directly on the exhaust air after the optical device is cooled, the above heat wave problem cannot be solved.

  As another conventional example, a liquid crystal projector includes a cooling fan that generates cooling air for cooling the liquid crystal panel and an air duct that guides the cooling air to the liquid crystal panel, and a Peltier element is disposed in the air duct. However, there is one that improves the cooling effect by absorbing the heat of the cooling air by the Peltier element (see, for example, Patent Document 3). However, the structure is complicated, such as arranging a Peltier element in the air duct, and the cooling air by the Peltier element cools the liquid crystal panel and not the exhaust air directly. The problem cannot be solved.

Furthermore, as another conventional example, it is attached to the main frame of the projector device, has an optical element composed of a dichroic prism, a liquid crystal panel, and a polarizing plate, and has a Peltier element with a heat radiating plate attached to the heat radiating surface portion, There is a projector device that cools an optical element by arranging the cooling surface portion exposed in a duct and connecting the fan and the air outlet with a duct (see, for example, Patent Document 4). However, even in this apparatus, the cooling air from the blower fan is further cooled by the Peltier element to cool the optical element, and the exhaust air after cooling the optical element is not directly cooled. Similarly, the heat wave problem cannot be solved.
Japanese Patent Laid-Open No. 10-90811 JP 2003-57754 A JP-A-8-194201 Japanese Patent Laid-Open No. 2003-233132

  The present invention has been made to solve the above-described problem, and based on a detection voltage signal of a temperature sensor, a cooling fan that sends cooling air, and cool air that has been heated to a high temperature after cooling the light source. By controlling the Peltier element, the temperature of the exhaust air from the projector is lowered, and the direction of the exhaust vent is away from the optical path of the projected image, reducing the effect of heat waves caused by the hot air of the exhaust air An object of the present invention is to provide a small, high-brightness projector apparatus that can obtain a stable projection image.

In order to achieve the above object, according to the first aspect of the present invention, an image formed by the DMD is formed by irradiating a DMD (digital micromirror device) with light from a light source condensed by a condensing optical unit. In a projector device that obtains an enlarged image by projecting with a projection optical unit that includes a projection lens for projecting, an exterior case of the main body unit having an exhaust port that fits with the main body unit of the projector device and covers a front surface A front cover, a cooling fan that cools the light source, and a rotation fan that is rotationally controlled by voltage; a Peltier element that cools the hot air generated by the cooling fan cooling the light source; and the projector and at least one or more temperature sensors for detecting the temperature in the apparatus, and disposing the projection lens on the front side of the outer case, the exhaust port of the front cover The air hole has a plurality of air holes, and the air holes (exhaust gas) discharged from the projector device obliquely penetrate the front cover in a direction away from the projection direction of the projection optical unit. The cooling surface is disposed at a position opposite to the cooling fan of the light source or / and a position close to an exhaust port inside the front cover so that the cooling surface is in contact with the hot air. An air flow rate that is disposed near a light source in the apparatus, detects an air temperature in the projector apparatus and outputs a detection voltage signal, and changes the rotation speed of the cooling fan based on the detection voltage signal of the temperature sensor. And controlling the surface temperature of the Peltier element by changing the voltage applied to the Peltier element based on the detection voltage signal of the temperature sensor. By lowering the temperature of the hot air exhausted from the motor unit, in which to be able to reduce the effect of the heat wave by hot air exhausted from the device.

  According to the invention of claim 1, based on the detected voltage signal of the temperature inside the apparatus from the temperature sensor, the number of rotations of the cooling fan that sends the cooling air and the hot air that has been heated to high temperature after cooling the light source are cooled. By electronically controlling the surface temperature of the Peltier element, the temperature of the hot air exhausted from the projector can be automatically reduced, and the temperature in the apparatus can be kept within the allowable temperature range. Further, by disposing the direction of the vent hole of the exhaust port for discharging the hot air away from the optical path of the projection image, it is possible to reduce the influence of the heat wave caused by the hot air exhausted from the apparatus. As a result, a highly reliable, small, and high-brightness projector device capable of obtaining a stable and beautiful projection image can be realized.

  Hereinafter, a projector according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the external appearance of the projector apparatus of this embodiment. The projector apparatus 1 (hereinafter abbreviated as “projector”) generates an image based on image data input from a television receiver, a video tape recorder, a DVD player, a personal computer, etc., and enlarges the image on a screen for projection display. It is a device to do. The projector 1 supplies a projection lens 5 for projecting an image on the front surface of an exterior case 3 of the apparatus main body 2 (main body section) and air used for cooling a lamp inside the apparatus main body 2. The exhaust port 41 provided in the front case part 4 of the outer case 3, the exhaust port 22 provided on the side surface of the case, and the suction port 23 provided on the back surface of the case (see FIG. 2) And have.

  Next, the internal structure of the projector 1 will be described with reference to FIG. A casting engine 11 (projection optical unit) for generating and projecting an image based on light from a lamp box 7 and a lamp 8 (light source) stored in the lamp box 7 is placed in the outer case 3 of the apparatus body 2. ) Are arranged. The lamp box 7 includes a lamp 8 serving as a light source, a lamp reflector 9 that reflects and collects light emitted from the lamp 8, and a cut filter 10 that removes infrared rays and ultraviolet rays from the light emitted from the lamp reflector 9. Holding. The casting engine 11 includes a tablet lens 12 (condensing optical unit) for correcting the influence of the wavelength and the like on the light incident on the engine 11, and a reflection mirror 13 that reflects the light emitted from the tablet lens 12. A DMD (digital micromirror device) 14 that generates an image, a projection lens 5 that projects an image generated by the DMD 14, and the like are held based on the light guided by the reflection mirror 13 and the like. Further, the casting engine 11 has a DMD cover 15 between the DMD 14 and the projection lens 5 for protecting the DMD 14 from light heat. Further, between the lamp box 7 and the casting engine 11, a light tunnel 16 (condensing optical unit) configured by sticking four plate glasses into a cylindrical shape and a color wheel 17 for color separation are disposed. ing.

  The DMD 14 has a DMD mirror composed of a large number of micromirrors, and each micromirror constituting the DMD mirror is incident from the lamp 8 via the reflection mirror 13 and the like based on a video signal input from the outside. Can be switched to a white pixel state in which the reflected light is reflected toward the projection lens 5 or a black pixel state in which this light is reflected in a direction other than the projection lens 5. Switching between the white pixel and the black pixel is performed by changing the angle of the micromirror. Thereby, a video signal is converted into an optical signal, and a projection image is obtained.

  In FIG. 2, the lamp box 7 is provided with two ventilation nets 71 and 72 on each side of the cooling air suction side and the discharge side in order to pass the cooling air from the cooling fan 6 for cooling the light source. The front cover portion 4 on the front surface of the outer case 3 has a plurality of exhaust ports 41. Each of these exhaust ports 41 includes a vent hole 42 that is disposed obliquely in a direction away from the direction of the projection screen. Further, the front cover portion 4 has an air guide plate 43 that guides the exhaust air to the vent hole 42. In order to cool the hot air from the ventilation net 72 on the side of the discharge side of the lamp box 7, Peltier elements P 1 and P 2 are provided in the vicinity of the ventilation net 72, and subsequently the hot air exhausted from the lamp box 7 is cooled. For this purpose, Peltier elements P3 and P4 are disposed in the vicinity of the inner surface of the exhaust port 41 of the front cover portion 4 (front cover). A temperature sensor 20 for measuring the environmental temperature in the apparatus 1 is disposed at a position where the air temperature in the vicinity of the lamp box 7 or the exhaust port 41 can be measured, and detects and detects the air temperature in the projector apparatus. A voltage signal is output, and based on the detected voltage signal, the number of revolutions of the cooling fan 6 and the voltage of the Peltier elements P1 to P4 are controlled to adjust the temperature in the apparatus. This voltage control enables high-speed and highly accurate temperature control. In addition, this temperature control can be controlled step by step to about five steps according to the measured temperature.

  In the above configuration, the cooling air from the cooling fan 6 enters the lamp box 7 from the ventilation network 71 on the side surface of the lamp box 7, cools the lamp 8 in the lamp box 7, and the ventilation network 72 on the opposite side surface. Exhausted from. At this time, the exhaust air is cooled by the Peltier elements P1 and P2 disposed in the ventilation net 72, and then further cooled by touching the Peltier elements P3 and P4, and exhausted through the vent holes 42. From the mouth 41, it is discharged obliquely in a direction away from the optical path 21 of the projected image. Here, the air guide plate 43 is an air reflecting plate for guiding the flow of the exhaust air to the vent hole 42. A dotted arrow A in the figure shows the flow of cooling air from the cooling fan 6. As this arrow indicates, all the exhaust air flows in a direction away from the optical path 21 of the projection image, so that the hot air of the exhaust air does not enter the optical path 21 of the projection image, and the influence of the heat wave is avoided. Can do.

  FIG. 3 shows a specific configuration for attaching the Peltier elements P1 and P2 to the lamp box 7 in FIG. In the figure, the lamp box 7 has bridges 77a, 77b, 77c, and 77d that bridge the ventilation nets 72a, 72b, 72c, and 72d in the horizontal direction. A Peltier element P1 is disposed between the bridges 77a and 77b, and a Peltier element P2 is disposed between the bridges 77c and 77d with the respective cooling surfaces facing the lamp box 7 side. Each Peltier element P1, P2 has a lead wire (not shown) for supplying power. Here, the cooling air from the direction of arrow B blown from the cooling fan 6 is heated by the lamp 8 to become hot air, but since this hot air directly touches the cooling surface of the Peltier elements P1 and P2, it is efficient. To be cooled. Further, since the Peltier elements P1 and P2 are held by the casing of the lamp box 7, it is easy to mount and does not take a place, so that the apparatus can be miniaturized.

  Next, a control flow for controlling the environmental temperature in the projector 1 will be described with reference to a flowchart shown in FIG. First, an allowable temperature range (within 80 ° C.) of the environmental temperature in the projector 1 is set in advance (S1), and then the temperature of the air in the vicinity of the lamp 8 in the apparatus is measured by the temperature sensor 20 (S2). Then, in a microcomputer (hereinafter abbreviated as “microcomputer”) provided for performing various controls in the projector 1, the measured temperature is compared with the previously set temperature (S 3). If it is within (YES in S4), the rotation speed of the cooling fan is maintained as it is (S5), the temperature of the cooling element is also maintained as it is (S6), and the temperature in the apparatus 1 is the allowable temperature. Maintained within range. Then, the temperature is fed back to the temperature measurement step (S2), and the temperature is controlled by the microcomputer so that the temperature in the apparatus is continuously maintained within the allowable temperature range. In S4, if the measured temperature falls outside the set allowable temperature range (NO in S4) and is higher than the allowable temperature range (YES in S7), the rotational speed of the cooling fan is increased (S8). Then, by raising the voltage applied to the Peltier element and lowering its surface temperature (S9), the temperature in the apparatus is controlled to be lowered. Then, the temperature is fed back to the temperature measurement step (S2), and the temperature is repeatedly controlled by the microcomputer until the temperature in the apparatus falls within the allowable temperature range. In S7, when the measured temperature is below the allowable temperature range (NO in S7), the number of rotations of the cooling fan 6 is decreased (S10), and the surface temperature is increased by lowering the voltage applied to the Peltier element (S11). ), The temperature in the apparatus is raised, and, similarly to the above, the temperature is fed back to the temperature measurement step (S2), and the temperature is controlled by the microcomputer so that the temperature in the apparatus falls within the allowable temperature range. Such temperature control makes it possible to maintain the temperature in the apparatus within the allowable temperature range.

  As described above, according to the projector 1 of the present invention, the cooling fan 6 is controlled based on the detection voltage signal of the temperature sensor 20 arranged in the apparatus 1, and the Peltier is controlled based on the detection voltage signal of the temperature sensor 20. By controlling the elements P1 to P4, the cooling of the air temperature in the apparatus 1 can be performed powerfully and effectively by two cooling actions. Further, since the temperature of the exhaust air from the projector 1 can be electronically controlled, the internal temperature of the projector 1 and the exhaust temperature to the outside are automatically controlled so that the temperature inside the apparatus is always within the allowable temperature range. Can be kept in. Further, by disposing the direction of the vent hole 42 of the exhaust port 41 in a direction away from the optical path 21 of the projection image, it is possible to further reduce the influence of heat waves caused by the high-temperature exhaust air. As described above, it is possible to realize a highly reliable, small-sized and high-intensity projector that can prevent the occurrence of fluctuations on the image projected on the screen and obtain a stable and beautiful projected image.

  In addition, this invention is not restricted to the said embodiment, Various deformation | transformation are possible. By arranging multiple temperature sensors and Peltier elements in the device, detecting the temperature at each position and using it as a control signal, the surface temperature of the Peltier element at each position can be changed to finely optimize the temperature inside the device. Can be adjusted. Moreover, you may use the module type thing which mounts a heat sink on a heat generating surface as a Peltier device.

  In the above embodiment, a DMD (digital micromirror device) is used as a light valve for converting a video signal as an electrical signal into a video signal as an optical signal. It can also be applied to projectors using other light valves.

1 is a perspective view showing an external appearance of a projector device according to a first embodiment of the present invention. FIG. 2 is a partially broken plan view showing an internal configuration of the projector device. The figure which shows how to attach the Peltier device to the lamp box in the said projector apparatus. 6 is a flowchart showing temperature control processing in the projector device. Explanatory drawing regarding the mechanism of the fluctuation | variation generation | occurrence | production in the conventional projector apparatus.

Explanation of symbols

1 Projector (Projector device)
2 Main unit (main unit)
4 Front cover (front cover)
6 Cooling fan 8 Lamp (light source)
11 Casting engine (projection optics)
16 Light tunnel (Condensing optics)
20 Temperature sensor 41 Exhaust port 42 Ventilation hole P1, P2, P3, P4 Peltier element

Claims (1)

The light from the light source condensed by the condensing optical unit is irradiated to a DMD (digital micromirror device) and projected by a projection optical unit including a projection lens for projecting an image formed by the DMD. In the projector device that obtains an enlarged image as described above,
A front cover of the outer case of the main body having an exhaust port that fits with the main body of the projector device and covers the front surface;
A cooling fan that cools the light source and that is rotationally controlled by voltage; a Peltier element that cools the hot air generated by the cooling fan cooling the light source;
And at least one temperature sensor for detecting a temperature in the projector device,
The projection lens is disposed on the front side of the exterior case,
The exhaust port of the front cover has a plurality of vent holes, and the vent holes obliquely penetrate the inside of the front cover in a direction in which air (exhaust gas) discharged from the projector device is away from the projection direction of the projection optical unit. And
The Peltier element is disposed at a position opposite to the cooling fan of the light source, or / and a position close to an exhaust port on the inner side of the front cover so that the cooling surface is in contact with the hot air,
The temperature sensor is disposed in the vicinity of a light source in the projector device, detects an air temperature in the projector device, and outputs a detection voltage signal,
The air volume is controlled by changing the number of rotations of the cooling fan based on the detection voltage signal of the temperature sensor, and the voltage applied to the Peltier element is changed based on the detection voltage signal of the temperature sensor. By controlling the surface temperature of the projector, the temperature of the hot air exhausted from the projector device is lowered, so that the influence of heat waves caused by the hot air exhausted from the device can be reduced.

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