JP4796709B2 - LCD projector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal projector, and more particularly, to a liquid crystal projector capable of efficiently removing and discharging dust or the like adhering to a liquid crystal panel using a forced air cooling time after power is turned off.
[0002]
[Prior art]
4A and 4B are schematic views showing the configuration of an optical unit 50 of a conventional liquid crystal projector, where FIG. 4A is a plan sectional view and FIG. 4B is a longitudinal sectional view of a liquid crystal panel section. Light rays emitted from a light source 53 that covers a lamp or the like with a reflecting mirror are blocked by ultraviolet rays and infrared rays by a cut filter, pass through a polarization conversion element 54 and a lens array 52 disposed in the housing 12, and are mainly visible light. The component enters the mirror 62a. Red (R) light is separated and reflected by the mirror 62a, and passes through the red liquid crystal panel 57b via the mirror 63a.
[0003]
On the other hand, the light beam that has passed through the mirror 62a is separated into green (G) light and blue (B) light by the mirror 62b, and the reflected G light beam passes through the green liquid crystal panel 57c. The B light transmitted through the mirror 62b passes through the blue liquid crystal panel 57a through the lens, the mirror 63b, the lens, and the mirror 63c. The three colors of light that have passed through the liquid crystal panels 57a, 57b, and 57c are combined by the cross dichroic prism 51, enlarged by the projection lens 56, reflected by the rear mirror (not shown), and screen (not shown). ).
[0004]
In order to lower the heat of the liquid crystal panel inside the optical unit 50, the air is cooled by a cooling fan 60 during operation as shown in FIG. Then, for some time after the power is turned off, forced air cooling with a fan is performed for the purpose of improving the relighting performance of the lamp and lowering the temperature of the housing 12. Cooling air is taken into the housing 55 by the fan 60 through the filter 61, passes through the rectifying fins 59, and is sent to the liquid crystal panel section partitioned by the partition plate 58, and the liquid crystal panel and the cross dichroic prism 51 is cooled. The wind that has passed through the liquid crystal panel cools the inside of the other housing and is discharged outside.
[0005]
[Problems to be solved by the invention]
If the filter 61 is made finer, the filter 61 is clogged and the air volume is reduced, so that the temperature inside the housing is likely to rise. Therefore, intrusion of dust into the housing is an unavoidable problem.
[0006]
The dust that has entered the housing adheres to the surface of the liquid crystal panel and degrades the image quality. To prevent these, during normal operation, it may be possible to blow off these dusts with the air generated by the fan for air cooling, but in order to blow off the dust, increase the air volume or concentrate on a place where dust is likely to adhere. It is necessary to apply wind, etc., which increases noise during normal operation and hinders efficient reduction of the temperature inside the set.
[0007]
As a technique for solving the above-mentioned problems, Japanese Patent Laid-Open No. 2000-122024 discloses a cooling fan that removes dust being cooled from the outside with a filter, and further removes dust through a conditioned fin with an adhesive attached. However, a method for reducing the adhesion of dust to the liquid crystal panel is disclosed. Japanese Patent Application Laid-Open No. 2000-180816 discloses that dust is charged on the windward side of the cooling fan, and this dust is removed by an electrostatic filter provided on the leeward side to reduce the adhesion of dust to the liquid crystal panel. Is disclosed.
[0008]
However, in the technique of the former publication, if dust adheres to the pressure-adjusting fin adhesive material, the performance of the adhesive material deteriorates and the dust removal performance deteriorates. Therefore, frequent replacement of the adhesive material is necessary. Further, the technique of the latter publication has a problem that the apparatus becomes complicated and the apparatus cannot be reduced in size.
[0009]
Accordingly, the present invention provides a liquid crystal projector that solves the above-mentioned problems of the prior art and can efficiently remove and discharge the dust inside the set.
[0010]
[Means for Solving the Problems]
The liquid crystal projector of the present invention includes means for separating light emitted from a light source into three primary colors, three liquid crystal panels provided at required positions on the optical axis of each light, and transmitting the separated light. A cross dichroic prism for synthesizing the lights transmitted through the liquid crystal panel, and a projection lens for enlarging and projecting the synthesized light onto a screen, the three liquid crystal panels being the cross dichroic Opposite the three side surfaces of the prism, it is arranged inside a box that is opened up and down together with the cross dichroic prism, and is sent to the inside of the box by a cooling fan below or above the cross dichroic prism and each liquid crystal panel. Opening and closing means for controlling the blowing position of the cooling air to be blown to the cross dichroic prism and the liquid crystal panels includes the box. Characterized in that it is arranged Guyo.
[0011]
The opening / closing means includes four openable doors for blowing out the cooling air corresponding to the cross dichroic prism and the liquid crystal panels, respectively, and the four doors can be controlled to open and close independently.
[0012]
The opening / closing means includes an opening / closing control mechanism for the door that blows the cooling air to each of the liquid crystal panels in order. The opening / closing means is provided with a control mechanism for closing all of the doors after the power source of the light source is cut off and the cooling fan is operated for a predetermined time, so that dust enters the liquid crystal panel unit after the liquid crystal projector is used. Can be prevented.
[0013]
As the opening / closing means in the liquid crystal projector of the present invention, a louver or a slide can be used.
[0014]
The liquid crystal projector of the present invention can be provided with an operation means that can select an operation of the opening / closing means on an on-screen menu screen.
[0015]
Further, in the liquid crystal projector of the present invention, the cooling fan is provided with a rotation speed control mechanism, the rotation speed of the cooling fan is increased during the forced air cooling time, and the amount of cooling air blown out from the door can be further increased.
[0016]
The liquid crystal projector of the present invention can increase the amount and strength of the cooling air blown to the liquid crystal panel after the light source is turned off without installing an air nozzle as in the prior art, and adheres to the surface of the liquid crystal panel. The removed dust can be mechanically removed efficiently by the cooling air, and the performance can be prevented from being deteriorated by the adhesion of the dust on the liquid crystal panel.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
[0018]
FIG. 1 is a diagram of a main part showing an embodiment of a liquid crystal projector of the present invention, where (a) is a plan sectional view of an optical unit 20 part, (b) is a longitudinal sectional view of a liquid crystal panel part, and (c). FIG. 3 is a perspective view of a louver part.
[0019]
Referring to FIG. 1, the liquid crystal projector of the present invention includes a polarization conversion element 13, a lens array 14, mirrors 8a, 8b, and 9a for separating light emitted from a light source 10 having a lamp or the like covered with a reflecting mirror into three primary colors. , 9b, 9c, etc., liquid crystal panels 3a, 3b, 3c for transmitting each separated light, cross dichroic prism 1 for combining the light transmitted through each liquid crystal panel, and the combined light is enlarged And a projection lens 11 for projecting onto the screen.
[0020]
Each liquid crystal panel is disposed to face the three side surfaces of the cross dichroic prism 1. The cross dichroic prism 1 and the liquid crystal panels 3a, 3b, 3c are composed of a partition plate 6 and are arranged in a box body whose top and bottom are open. A cooling fan 2 is provided below the box of the partition plate 6. Reference numeral 12 denotes a housing.
[0021]
Further, a louver 5 (opening / closing means) having a door that can be opened and closed so as to close the opening of the box body is disposed just below the cross dichroic prism 1 and the liquid crystal panel of the partition plate 6. The blowout position of the cooling air sent to the inside of the box body to the cross dichroic prism 1 and each liquid crystal panel is controlled.
[0022]
While the louver 5 is driving the liquid crystal projector, the entire door is opened as shown in FIG. As shown in FIG. 1C, the louver 5 is close to the open / close doors 5 a, 5 b, 5 c provided near the lower ends of the liquid crystal panels 3 a, 3 b, 3 c and the lower surface of the cross dichroic prism 1. And an open / close door 5d.
[0023]
The louver 5 can be provided with a mechanism capable of independently controlling the opening and closing of each door. As an example of this mechanism, there is a mechanism that allows the projector to select an open / close mode (forced discharge mode) of the open / close door on an on-screen menu screen. When the user selects it, the same state as the forced air cooling after the power is turned off is executed to force the dust to be discharged. In this case, if the user does not press the power-off (OFF) key, the operation is continued so that this state continues. This is an effective means in a situation where there is a limit to the forced air cooling time after the power is turned off, and dust cannot be blown within this time.
[0024]
In FIG. 1B, the louver 5 is used as the opening / closing means, but a slide can be used instead. In FIG. 1B, the louver and the fan are provided below the cross dichroic prism 1 and each liquid crystal panel, but the louver and the fan can be provided above the cross dichroic prism 1 and each liquid crystal panel. .
[0025]
Next, the operation of the embodiment of the liquid crystal projector of the present invention will be described with reference to FIG.
[0026]
The air flow indicated by the arrows in FIG. 2A is during air cooling when the projector is operating. The outside air passes through the filter 7 by the fan 2 and is drawn into the box body of the partition plate 6. At this time, the louvers 5 are all open, and the air taken in by the fan 2 passes through the louvers 5, cools the cross dichroic prism 1 and the liquid crystal panels 3a, 3b, 3c, and escapes to the exhaust duct. Go.
[0027]
Next, when the power source of the light source is turned off, as shown in FIG. 2B, the other doors are closed while the door 5b of the louver 5 is kept open. At this time, all the air taken in by the fan 2 is concentrated on the open / close door 5b of the louver 5 and the air volume is increased. As a result, the dust that has entered the gap in the liquid crystal panel 3b is removed and discharged to an exhaust duct (not shown).
[0028]
Further, as shown in FIG. 2 (c), only the open / close door 5a of the louver 5 near the liquid crystal panel 3a is opened, all the other open / close doors are closed, dust contained in the gap of the liquid crystal panel 3a is removed, and the exhaust duct is discharged. And discharge. Finally, dust is eliminated in the same manner for the third liquid crystal panel 3c. These operations are performed during a forced air cooling period after the power is turned off.
[0029]
Further, by controlling the power supply voltage applied to the fan 2, increasing the fan voltage after the power is turned off, and increasing the rotational speed of the fan 2, a larger air volume can be obtained.
[0030]
In FIG. 2, the open / close doors are opened in order and the liquid crystal panels are blown in order. However, as shown in FIG. 3, the open / close door 5d is closed and all the open / close doors 5a, 5b, 5c are opened to open the liquid crystal panel units. May be blown at once to eliminate dust in the gaps between the liquid crystal panels. In this case, the air volume of the fan 2 is increased.
[0031]
In addition, if all the open / close doors are closed when the forced air cooling time ends, the intrusion of dust into the housing can be reduced.
[0032]
【The invention's effect】
As described above, in the liquid crystal projector according to the present invention, the following effects can be obtained by providing the opening / closing means for controlling the blowing position of the cooling air to the liquid crystal panel portion on the lee of the cooling fan.
(1) Utilizing the forced air cooling period after turning off the light source of the projector, the air flow to the liquid crystal panel can be automatically increased, and dust can be efficiently and forcibly discharged from the surface of the liquid crystal panel. Performance degradation due to dust can be prevented.
(2) Since the air volume inside the set is increased after the projector is turned off, the problem of noise caused by the fan during normal operation can be avoided.
[Brief description of the drawings]
1A and 1B are main part views showing an embodiment of a liquid crystal projector of the present invention, FIG. 1A is a plan sectional view of an optical unit 20 part, FIG. 1B is a longitudinal sectional view of a liquid crystal panel part, and FIG. FIG. 3 is a perspective view of a louver part.
FIG. 2 is a longitudinal sectional view of a liquid crystal panel portion for explaining the operation of the embodiment of the liquid crystal projector of the present invention.
FIG. 3 is a longitudinal sectional view of a liquid crystal panel portion for explaining the operation of the embodiment of the liquid crystal projector of the present invention.
4A and 4B are schematic views showing a configuration of an optical unit 50 of a conventional liquid crystal projector, in which FIG. 4A is a plan sectional view, and FIG. 4B is a longitudinal sectional view of a liquid crystal panel unit.
[Explanation of symbols]
1, 51 Cross dichroic prism 2, 60 Fan 3a, 3b, 3c, 57a, 57b, 57c Liquid crystal panel 5 Louver 6, 58 Partition plate 7, 61 Filter 8a, 8b, 9a, 9b, 9c Mirror 10, 53 Light source 11, 56 Projection lenses 12, 55 Housings 13, 54 Polarization conversion elements 14, 52 Lens array 59 Rectifier fins 62a, 62b, 63a, 63b, 63c Mirror

Claims (8)

Red emitted from the light source, blue, provided the required position of the optical axis of each of the green three color lights, the three liquid crystal panels wherein the color light you each transmission,
A cross dichroic prism for synthesizing the three color lights transmitted through the liquid crystal panel;
A projection lens for morphism projecting the combined light, a liquid crystal projector provided with,
Before SL three liquid crystal panels are arranged opposite to the three aspects of the cross dichroic prism,
Below the three liquid crystal panels, there are respectively provided openings through which cooling air sent by a cooling fan comes out,
The openings each have opening and closing means for opening and closing the openings ,
After cutting the power of the light source, and runs then to the cooling fan for a predetermined time, the liquid crystal projector Ru closing all apertures. The liquid crystal projector according to claim 1, wherein the openings are closed simultaneously. The liquid crystal projector according to claim 1 or 2 using louvers or slide as the switching means. The liquid crystal projector according to any one of 請 Motomeko 1-3 that comprise an operating means that can be selected on-screen menu of the operation of the switching means.   A method for discharging dust attached to a liquid crystal panel in a liquid crystal projector having a light source and a plurality of liquid crystal panels,
  Below the plurality of liquid crystal panels, a plurality of openings corresponding to each of the liquid crystal panels are provided so that cooling air sent by a cooling fan comes out,
  Each of the openings has an opening / closing means for opening and closing the opening,
  After the power source of the light source is cut off, one opening is opened by one opening / closing means, the other opening is closed by another opening / closing means, and the cooling air is blown to the liquid crystal panel corresponding to the one opening. A method for discharging dust adhering to the liquid crystal panel.   A method for discharging dust attached to a liquid crystal panel in a liquid crystal projector having a light source and a plurality of liquid crystal panels,
  Below the plurality of liquid crystal panels, a plurality of openings corresponding to each of the liquid crystal panels are provided so that cooling air sent by a cooling fan comes out,
  Each of the openings has an opening / closing means for opening and closing the opening,
  A method of discharging dust attached to the liquid crystal panel by opening all openings by all opening and closing means and blowing air to the plurality of liquid crystal panels at once after the power source of the light source is cut off.   The method for discharging dust adhering to the liquid crystal panel according to claim 5 or 6, wherein the number of revolutions of the cooling fan is increased after the light source is turned off.   Furthermore, an operation means that can select an operation of the opening and closing means on an on-screen menu screen,
  8. The liquid crystal panel according to claim 5, wherein after the operation of the opening / closing means is selected, dust is discharged from the liquid crystal panel by opening the opening and blowing air to the liquid crystal panel. To discharge dust adhering to the surface.

Images