JP2002174855A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of deterioration in the quality of video caused by dust included in external air being introduced into a casing of a color liquid crystal projection device in which an electric discharge lamp and an optical modulating means or the like that make misoperations by heat are air-cooled by a cooling fan. SOLUTION: In a color liquid crystal projection device 1, an air cooling fan cools portions which make misoperations by heat. The portions include an electric discharge lamp 6, special modulating elements 12R, 12G and 12B as optical modulating means, polarizing plates 17R, 17G and 17B, polarizing plates 18R, 18G and 18B and a PS converting element 8 or the like. An electrifying filter unit 99 using a dielectric body (an electret) that holds permanent polarization is provided outside an exhaust fan 25 which sucks in external air into a casing 2 and exhausts heated air to the outside. When electret is used for the filter, dust is collected without providing opposing electrodes and without applying a high voltage to the electrodes. The filter is exchanged as a disposable type filter. However, it is desirable that a washable filter is arranged in front of the unit 99 to extend the service life of the electrifying filter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device (projector device) having dustproofing measures, and more particularly to a projection type display device such as a liquid crystal projector device having dustproofing measures using a charge filter. .

[0002]

2. Description of the Related Art The temperature inside a liquid crystal projector increases. The details of the temperature rise inside the liquid crystal projector device will be described later in detail in connection with the embodiment of the present invention. However, heating of a discharge lamp disposed inside the liquid crystal projector device, light modulation means such as liquid crystal, and polarization Heating in polarizing means such as a plate becomes a problem. Therefore, the liquid crystal projector needs to be appropriately cooled.

Various methods have been proposed for cooling a liquid crystal projector device. However, as a relatively low-cost and easy-to-implement method, an air-cooling fan is provided to forcibly open the outside of the housing of the projector device. This is a method in which the temperature of the inside of the housing is suppressed by feeding the battery.

A liquid crystal and a polarizing plate are used as light modulating / polarizing means. For example, an image signal is given to the liquid crystal from an information device such as a personal computer, and an image corresponding to the image signal is projected on a screen located in front of the liquid crystal projector. Liquid crystal projector devices are becoming popular. In particular,
In such a liquid crystal projector device, when outside air is sent into the inside of the liquid crystal projector device using an air-cooling fan, dust, dust, dust, etc.
If dust (typically referred to as dust) adheres to the light modulating / polarizing means, there is a problem that image quality deteriorates, such as blurring of an image projected from the liquid crystal projector.

[0005] In order to prevent such deterioration in image quality, when the outside air is taken into the inside of the housing of the liquid crystal projector by an air-cooling fan, it is necessary to remove dust and the like contained in the outside air.

Several methods for eliminating such dust have been proposed so far. As a typical method, for example, electrodes facing a housing are arranged and a high voltage is applied to these electrodes. There is known a method of electrostatically collecting dust. A specific example will be described below.

Japanese Patent Application Laid-Open No. 10-10646 discloses a projector in which electrodes are arranged at opposing positions inside an air-cooling fan, and a high voltage is applied to these electrodes to electrostatically adhere dust to the electrodes. Prevent or reduce dust entering the inside of the device.

Japanese Patent Application Laid-Open No. 2000-69396 also discloses a method of eliminating the above-mentioned dust from entering the inside of the liquid crystal projector device by placing an electrode inside the air-cooling fan at a position facing the air-cooling fan with an air filter interposed therebetween. The dust filter is disposed to reduce dust entering the inside of the projector device by the air filter and the electrostatic force of the high voltage applied to the electrodes.

[0009]

Problems to be Solved by the Invention Japanese Patent Laid-Open No. 10-1064
No. 6, JP-A-2000-69396 and JP-A-2000-69396 disclose a method for removing dust electrostatically by applying a high voltage to the electrodes, in which a large number of electrodes must be arranged near the air-cooling fan. Therefore, the configuration of the projector device becomes complicated, and the projector device is expensive.

In both of these methods, since a high voltage needs to be applied between the electrodes, a high voltage power supply or a high voltage generating circuit must be provided in the projector. The installation of such a high-voltage power supply or high-voltage generation circuit has encountered problems such as an increase in the price of the projector device and an increase in the size of the projector device.

Further, in these methods, it is troublesome to remove or clean dust adhering between the electrodes, and there is a difficulty in maintaining and maintaining the projector device.

The present invention overcomes the above-described problems in a projector device (projection display device), efficiently eliminates dust having a size that affects image quality, and does not increase the size of the projection display device. An object of the present invention is to provide a projection type display device having a dust prevention function (means) that is easy to maintain and maintain without increasing the manufacturing price.

[0013]

According to the present invention, there is provided a projection type display apparatus for cooling the illumination means and / or the light modulation means by taking in outside air into a housing in which the illumination means and the light modulation means are accommodated. The present invention provides a projection display device characterized in that a charging filter using a dielectric material that maintains permanent polarization is provided in a housing portion through which the outside air passes.

As the charging filter, a charging filter using a non-woven fabric as a raw material, such as polypropylene or the like, which is a dielectric material that maintains permanent polarization, is used. A dielectric material that retains permanent polarization (a state like a permanent magnet) is called an electret. If such an electret is used as a charging filter, there is no need to provide a counter electrode, and a high voltage is applied to the counter electrode. Dust can be collected without the need. Preferably, the charging filter is replaceably attached from outside the housing.

Since such a charge filter is in the form of a nonwoven fabric, it can be cut freely, and can be used like a normal filter. That is, in the present embodiment, the charging filter can be replaced as a disposable type. As described above, since the charging filter of the present invention is used after being replaced, as described in JP-A-10-10646 and JP-A-2000-69396, it is necessary to attach the electrode to an electrode required when an electrode is provided. It is not necessary to remove (clean) the dust.

Preferably, the charging filter is provided on an outer surface of the casing located outside a position where the air cooling fan is disposed. In order to facilitate replacement without reducing the collection effect even during operation of the projection display device, preferably, an air cooling fan for introducing the outside air into the housing is provided inside the housing, and a charging filter is provided. , Provided on the surface of the outer housing on which the air-cooling fan is provided. That is, when the charging filter is mounted on the surface of the housing, the air-cooling fan is not removed and the like, and even during the operation of the projection display device,
The charging filter can be replaced.

When the charging filter is attached to the housing, the user can visually recognize the collection state of the charging filter, and can easily determine the timing of replacement of the charging filter.

Preferably, the charging filter has a large effect of deteriorating the quality of an image, for example, about 1 to about 1.
This is a charging filter that effectively collects dust of several tens of μm.

Specifically, the air cooling fan is provided in an optical unit case provided inside the housing, an outside air intake opening is provided in a surface of the housing, and the outside air is opened by the operation of the air cooling fan. Outside air is introduced into the housing via the intake opening.

More specifically, a frame is provided outside the housing around the outside air intake opening formed in the housing so that the charging filter can be inserted into and removed from the housing.

More specifically, a screw hole is formed around the outside air intake opening formed in the housing, and a cover,
A charging filter unit including a non-woven electret fixed to the cover is detachably fixed to the housing via the screw hole. Also, specifically, a locking hole is formed around the outside air intake opening formed in the housing,
A charging filter unit comprising a cover and a non-woven electret fixed to the cover and having a projection engaged with the locking hole is detachably fixed to the housing via the locking hole.

Preferably, the charging filter is formed so as to be jagged so as to increase the effective dust collecting area per unit area. Preferably, the charging filter is divided into a plurality of parts and is replaceable.

Specifically, the charging filter is formed continuously, and the continuous charging filter is movable on the front surface of the outside air intake opening provided on the surface of the housing.

Preferably, there is provided a sensor for detecting the dust collecting state of the charging filter, and evaluation means for evaluating the dust collecting state of the charging filter in accordance with the reading of the sensor. This makes it possible to appropriately determine the replacement time due to the deterioration of the performance of the charging filter.

More preferably, a rewind reel,
A take-up reel, and a rotation driving means for rotating the take-up reel, wherein a continuous charge filter is used as the charge filter, and an unused portion of the continuous charge filter is loaded on the rewind reel. , The used portion is wound around the take-up reel, and when the evaluation unit detects that the dust collection state of the charging filter exceeds a predetermined level, the rotation driving unit is driven, The rotation drive means rotates the take-up reel so that the charging filter winds up the take-up reel for a predetermined length. Preferably, the charging filter loaded between the rewind reel and the take-up reel has a predetermined tension, and the tension filter is configured to substantially close the outside air intake opening on the surface of the housing. An application means is provided.

More preferably, a non-electret having a performance of collecting dust larger than the charge filter without using a dielectric that maintains permanent polarization in front of the charge filter and adjacent to the charge filter. -A filter can be provided. Preferably, the non-electret filter is exchangeably mounted. Further, the non-electret filter is desirably washable.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the projection type display device of the present invention will be described with reference to the accompanying drawings.

First Embodiment FIGS. 1 and 2 are a plan view and a sectional view of a color liquid crystal projector using a liquid crystal and a polarizing plate as light modulating / polarizing means as a first embodiment of the present invention. FIG.
And the color liquid crystal projector device 1 illustrated in FIG.
The optical unit case 4 having a substantially L-shaped planar shape is installed in a horizontal state inside the housing 2 with the stand 3, and a color image is projected inside the optical unit case 4 onto a screen or the like. The optical unit 5 is stored in a horizontal state.

The configuration of the optical unit 5 will be described. The optical unit 5 has an optical axis P1 of a discharge lamp 6 as a light source.
On the line, a fly-eye (fly-eye) lens group 7 serving as illumination optical means and a PS conversion element 8 are arranged in series.

The optical unit 5 has a mirror 9 for deflecting the optical axis P1 by 90 ° and a mirror 9 for 45 ° on the line of the deflected optical axis P2.
Two dichroic mirrors 10R and 10G that are inclined and arranged at predetermined intervals to separate light from the discharge lamp 6 into red (R), green (G), and blue (B); P
2, a mirror 16 for deflecting the bent optical axis P5 by 90 °, and a direction of the light deflected (branched) by the dichroic mirror 10R, and the optical axis P3 for 90 °. And a mirror 15. The second optical unit 5 has optical axes P3, P4, P5
, Three condenser lenses 11R, 11G, 1
1B, three spatial modulation elements 12R, 12G, and 12B using a transmissive liquid crystal panel;
It has a square cross prism 13 as a light combining means disposed on the exit path P6 of R, 12G, 12B, and a projection lens 14 disposed on the exit side of the cross prism 13.

The fly-eye lens group 7 divides the light L1 having the intensity distribution from the discharge lamp 6 into a number of light spots, and divides the number of the divided light spots into three spatial modulation elements 1
This is provided in order to make the luminance distribution of the illumination light over the entire screen of the spatial modulation elements 12R, 12G, 12B uniform by superimposing them in the 2R, 12G, 12B.

The PS conversion element 8 is composed of a deflecting beam splitter arranged in a strip shape and a phase difference plate provided intermittently corresponding to the deflecting beam splitter. It is provided to convert the polarization direction of the wave component into an S-wave and output light containing a large amount of the S-wave component as a whole.

The three condenser lenses 11R, 11G,
11B and three spatial modulation elements 12R, 12G, 12B
Are disposed at positions in three directions close to the three surfaces of the square cross prism 13, respectively.

In the optical unit 5, three polarizing plates 17R, 17G, 17B, and 3 are provided on the incident side and the exit side of the three spatial modulation elements 12R, 12G, and 12B, respectively.
The polarizing plates 18R, 18G, 18B are arranged in parallel with each other. In the illustrated example, the three polarizing plates 17R, 17G, and 17B are disposed on the exit sides of the three condenser lenses 11R, 11G, and 11B.
The three polarizing plates 18R, 18G, 18B are arranged on the incident side of the cross prism 13.

An outline of the operation of the illustrated liquid crystal projector 1 will be described. The light L1 from the discharge lamp 6 is made uniform by the fly-eye lens group 7, and the polarization directions of the light made uniform by the PS conversion element 8 are aligned. The light L2 whose polarization direction has been aligned is reflected by the dichroic mirror 10R and the red component light travels along the optical path P3. The condenser lens 11R, the first polarizer 17R, the spatial modulator 12R, and the second polarizer 18R. Incident on. The light transmitted through the dichroic mirror 10R is reflected by the dichroic mirror 10G so that the green component light is reflected and travels along the optical path P4, and the condenser lens 11G and the first polarizer 1
7G, the spatial light modulator 12G, and the second polarizer 18G. The light of the blue component transmitted through the dichroic mirror 10G is deflected by 90 ° by the mirror 103 and the mirror 16 and travels along the optical path P5.
B, the light enters the first polarizing plate 17B, the spatial modulation element 12B, and the second polarizing plate 18B.

For example, when video signals corresponding to the three primary colors R, G, and B are applied to the three spatial modulation elements 12R, 12G, and 12B using transmission type liquid crystal, respectively, the three spatial modulation elements 12R, 12G, and 12B respond to these video signals. The state of light passing through the liquid crystal changes, that is, the plane of polarization rotates. Spatial modulation element 12
Light emitted from R, 12G, and 12B is reflected by polarizing plates 18R,
18G and 18B, and receives polarized light there to produce image light L
R2, LR2 and LG2 enter the cross prism 13. Therefore, the dichroic mirror 10R, 1
0G and the three-color lights LR1 and L emitted from the mirror 16
R1, LG1 are polarizing plates 17R, 17G, 17B, spatial modulation elements 12R, 12G, 12B and polarizing plates 18R,
When transmitting through 18G and 18B, the light intensity is changed according to the video signal. The image lights LR2, LR2, and LG2 that have entered the cross prism 13 are combined by the cross prism 13, and the combined image light L3 is emitted along the optical axis P6 by the projection lens 14 and is positioned in front of the projection lens 14. (Not shown), a color image is displayed.

As described above, the liquid crystal projector 1
Are spatial modulation elements 12R, 12G,
When a video signal is applied to 12B, the polarizing plates 17R, 17R
G, 17B, the spatial modulation elements 12R, 12G, 12B and the light modulating / polarizing means by the polarizing plates 18R, 18G, 18B light modulate the three-color light LR1, LR1, LG1 to form a color image according to the video signal. Can be displayed on the screen. Such a video signal can be output to the liquid crystal projector 1 directly from a personal computer or the like, for example. Therefore, the liquid crystal projector device 1 can display an image corresponding to an image signal output from a personal computer or the like on a screen.

The temperature rise of the liquid crystal projector 1 will be described.

First, the temperature rise by the discharge lamp 6 will be described. An ultra-high pressure mercury bulb having an output of 150 W or more is often used for the discharge lamp 6.
Such an ultra-high pressure mercury bulb is built in a reflector (reflecting mirror). When the discharge lamp 6 is operated for a long time, the temperature around the ultra-high pressure mercury bulb and inside the reflector increases. If the temperature rise exceeds the limit, a devitrification phenomenon occurs in which the light transmission of the ultrahigh-pressure mercury bulb decreases. Therefore, in order to operate the liquid crystal projector 1 with high reliability for a long time, it is necessary to prevent the temperature around the ultra-high pressure mercury bulb and the inside of the reflector from becoming higher than a certain temperature.

The rise in the temperature of the discharge lamp 6 is caused by the PS conversion element 8, the polarizing plates 17R, 17G, 17B, and the polarizing plates 18R, 18R housed inside the liquid crystal projector 1.
In some cases, the temperature rise of 18G and 18B may be affected.
Therefore, in order to operate the liquid crystal projector 1 with high reliability for a long time, it is necessary to prevent the temperature inside the liquid crystal projector 1 from rising due to the discharge lamp 6 to a certain temperature or higher.

Next, the spatial modulation elements 12R, 12G, 1
Polarizing plates 17R, 17G, 17B arranged before and after 2B
The temperature rise in the polarizing plates 18R, 18G, 18B will be described. Spatial modulation elements 12R, 12G, 12B
The three first polarizers 17R, 17G, 17B and the three second polarizers 1 disposed on the incident side and the exit side of
8R, 18G, and 18B are three color lights LR1, LG1, and L
B1 and three image lights LR2, LG2, LB2 are arranged to make the polarization directions uniform. Three first polarizers 17R, 17G, 17B and three second polarizers 18R,
Each of 18G and 18B is formed by bonding a polarizing filter to a thin glass plate with an adhesive. Each of the polarizing plates 17R, 17G, and 17B and the polarizing plates 18R, 18G, and 18B thus formed is heated by the polarizing action, and the temperature of the backing material rises. When the temperature reaches a certain temperature, for example, 70 ° C. or higher, baking of the polarizing plate and a decrease in transmittance occur. Therefore, in order to operate the liquid crystal projector 1 with high reliability for a long time, the polarizing plates 17R, 17G, 17B and the polarizing plates 18R, 18B are required.
It is necessary to prevent the temperature rise of G and 18B from exceeding a certain temperature.

Further, a rise in the temperature of the PS conversion element 8 will be described. P incorporated in fly-eye lens group 7
The S conversion element 8 is formed by bonding a dielectric-coated glass plate in a strip shape with an adhesive. The adhesive is also stipulated with a guaranteed heat-resistant use temperature. If the adhesive is used beyond the guaranteed heat-resistant use temperature, the transmittance of the light L1 is reduced.
Therefore, in order to operate the liquid crystal projector device 1 with high reliability for a long time, it is necessary to prevent the PS conversion element 8 from becoming higher than a certain temperature.

Cooling Method In order to make the above-mentioned temperature rise to some extent, various cooling measures are taken for the liquid crystal projector 1.

(1) A method of cooling the polarizing plates 17R, 17G, 17B and the polarizing plates 18R, 18G, 18B will be described. Polarizing plates 17R, 17G, 17B and polarizing plate 18
In order to cool the R, 18G, and 18B, a thin axial fan (blowing fan) 2 is provided at a position directly below the cross prism 13 below the optical unit case 4 inside the housing 2.
1 is installed horizontally upward. Also, three cooling air outlets 22R, 22G, and 3C are provided in a portion located below the spatial light modulators 12R, 12G, and 12B in the lower portion 4a of the housing 2.
22B is provided. Further, three cooling air outlets 23R, 23G, and 23B are provided in portions of the upper part 4b of the housing 2 located above the spatial modulation elements 12R, 12G, and 12B.

When the axial fan (blowing fan) 21 is operated, the outside air is taken into the housing 2 by the rotation of the blowing fan 21, and the outside air is cooled by the cooling air outlet 22.
R, 22G, and 22B, polarizing plates 17R, 17G, and 17
B, and rises along the planes of the polarizing plates 18R, 18G, and 18B, and is discharged outside the housing 2 through the cooling air discharge ports 23R, 23G, and 23B. When the outside air taken in from the blower fan 21 passes along the surfaces of the polarizing plates 17R, 17G, 17B and the polarizing plates 18R, 18G, 18B, the polarizing plates 17R, 17G, 17B and the polarizing plates 18R, 18G,
Cool the temperature at 18B.

(2) Measures for cooling the PS conversion element 8 will be described. A small blower fan 24 is provided at a position directly below the PS conversion element 8 in the lower portion 4 a of the housing 2, and the blower fan 24
Cooling air outlet (not shown) between the sensor and the PS conversion element 8
And a cooling air outlet (not shown) is provided in the optical unit case 4 above the PS conversion element 8. When the blower fan 24 is operated, the outside air is taken into the casing 2 by the rotation of the blower fan 24, rises from the cooling air outlet along the PS conversion element 8, and passes through the cooling air discharge port to cool the casing. It is discharged outside the body 2. When the outside air taken in from the blower fan 24 passes through the outer surface of the PS conversion element 8, the temperature of the PS conversion element 8 is cooled.

(3) Countermeasures for cooling the discharge lamp 6 will be described. An exhaust fan 25 is provided on the inside rear surface of the housing 2 outside the optical unit case 4, and a cooling air inlet 2A is formed on the surface of the housing 2 facing the exhaust fan 25 (FIG. 3 ( B)). When the exhaust fan 25 is operated, the outside air is taken into the inside of the housing 2 from the cooling air inlet 2A by the rotation of the exhaust fan 25, and the discharge lamp 6
Is discharged to the outside of the optical unit case 4 through the periphery of the ultra-high pressure mercury bulb and the inside of the reflector.
It is discharged outside the housing 2. When the outside air taken in from the exhaust fan 25 passes through the discharge lamp 6, the temperature of the discharge lamp 6 is cooled.

First Embodiment of Charging Filter Unit Of the axial fan (blowing fan) 21, the blowing fan 24 and the exhaust fan 25, for example, the exhaust fan 25 will be described as a representative. And FIG. 3 (A),
As exemplified in (B), the charging filter unit 99 is provided so as to cover the cooling air inlet 2A formed in the housing 2 outside the optical unit case 4 to which the exhaust fan 25 is attached. .

The charging filter unit 99 may be screwed to the surface of the housing 2 or detachably locked with one touch to facilitate attachment and detachment to and from the housing 2.
It is configured.

The charging filter unit 99 comprises a charging filter 991 and a frame 993 for holding the charging filter unit 99 and mounting it on the housing 2.

When the charging filter unit 99 is screwed to the housing 2, a screw hole is formed around the cooling air inlet 2 A of the housing 2, and the frame 9 of the charging filter unit 99 is formed.
A screw through hole is also formed in 93. When attaching the charging filter unit 99 to the housing 2, a screw is screwed into a screw hole formed in the housing 2 through a screw through a screw through hole of the frame 993. When removing the charging filter unit 99 from the housing 2, the screw is removed. The charging filter 991 of the charging filter unit 99 is connected to the liquid crystal projector 1
Is operated, the air is sucked into the exhaust fan 25 together with the outside air by the suction force of the exhaust fan 25. At this time, the charging filter 991 is located in the vicinity of the cooling air intake 2A or slightly loosened so that the cooling air intake 2A of the housing 2 is completely closed and external air does not enter the housing 2 from the surroundings. It is preferable that the cooling air intake 2A be completely closed by the intake of the exhaust fan 25.

When the charging filter unit 99 is detachably locked to the housing 2 by one touch, a hole for locking is formed around the cooling air inlet 2A formed in the housing 2 so that the charging filter unit 99 can be charged. A projection having a shape that can be inserted and removed into the engagement hole is attached to the frame 993 of the filter unit 99. When the charging filter unit 99 is mounted on the housing 2, the projection of the frame 993 is fitted into a locking hole formed in the housing 2, and when the charging filter unit 99 is removed from the housing 2, the entire charging filter unit 99 is mounted. From the housing 2.

Various other forms of the charging filter unit 99 will be described later.

The reason that the charging filter unit 99 is provided on the surface of the housing 2 outside the exhaust fan 25 fixed to the optical unit case 4 is that the charging filter unit 99 is provided.
Alternatively, this is to facilitate replacement of the charging filter 991 held in the frame 993. That is, when the charging filter 991 collects dust, clogging occurs, the performance of collecting dust decreases, and the pressure loss when passing outside air increases, and the outside air suction force by the exhaust fan 25 increases. descend. Therefore, it is necessary to replace the entire charging filter unit 99 or only the charging filter 991. By mounting the charging filter unit 99 on the surface of the housing 2, the removal of the exhaust fan 25 is not performed, and even during the operation of the liquid crystal projector 1,
Replacement of charging filter unit 99 or charging filter 9
The replacement of 91 can be performed very easily.

The charging filter unit 99 is connected to the housing 2
When mounted on the surface, the user can visually recognize the collection state of the charging filter 991, and can easily determine the timing of replacement of the charging filter unit 99 or the charging filter 991.

Charge Filter Unit 99 As the charge filter 991, a charge filter using a nonwoven fabric as a raw material, such as polypropylene or the like, which is a dielectric material that maintains permanent polarization, is used. Electret refers to a dielectric material that maintains permanent polarization (a state like a permanent magnet). If such an electret is used, dust, dust, dust, etc. (hereinafter referred to as dust) without applying a high voltage to the electrodes. (Representatively, dust).

When an electret is used as the charging filter 991, as disclosed in JP-A-10-10646 and JP-A-2000-69396, no counter electrode is provided, and There is an advantage that dust can be collected without applying a voltage. Moreover, such a charged filter is in the form of a non-woven fabric, so that it can be cut freely and can be used like a normal filter. That is, in the present embodiment, the charging filter can be replaced and used as a disposable type. Further, when the charging filter sufficiently collects dust and the collecting performance is deteriorated, the charging filter is replaced.
As described in Japanese Unexamined Patent Application Publication No. 646 and Japanese Unexamined Patent Application Publication No. 2000-69396, it is not necessary to remove (clean) dust attached to the electrodes, which is necessary when the electrodes are provided.

As such a charge filter, for example, a non-woven polypropylene nonwoven fabric made of ultrafine fibers (microfibers), known as Filterlet S type by 3M Co., and a reinforcing nonwoven fabric also made of polypropylene are used. It is composed of two layers. Of the two layers,
The microfiber layer that collects dust is composed of microfibers with a fiber diameter of several μm made by the melt-prone manufacturing method, and each fiber has a permanent charge. Can be.

As such a charging filter, 3M
It is made of polypropylene non-woven fabric with no binder made of microfibers (microfibers), known as Filterlet G type, and obtains a high polarizability for each fiber before processing into a non-woven fabric. Therefore, a fiber made as a plate-like fiber having an average of 38 μm × 10 μm can be used.

When the above-described charging filter is used as the charging filter, dust collection efficiency is high and pressure loss is low.
There is an advantage that performance degradation is small in the long term even in a high temperature and high humidity environment. The high dust collecting effect means that the dust contained in the outside air stays in the charging filter unit 99 without being introduced into the housing 2. The low pressure loss has the advantage of not lowering the outside air suction performance of the exhaust fan 25. That is, when the external air suction effect of the exhaust fan 25 is reduced by providing the charging filter unit 99, the capacity and size of the exhaust fan 25 increase in order to enhance the performance of the exhaust fan 25.
It has been found that such an adverse effect does not occur when the above-described charging filter is used. The fact that there is little deterioration over a long period of time even in a high-temperature, high-humidity environment means that the liquid crystal projector 1 used under normal temperature and humidity conditions
Means that such a charge filter can be used.

According to the investigations and considerations of the inventors of the present invention, the collection effect is ideally in the range of visible light and ultraviolet and infrared rays on both sides of the visible light, and in terms of wavelength, 0.01.
Dust in the range of μm to several hundred μm is
R, 12G, 12B, polarizing plates 17R, 17G, 17B,
It has been found that the adhesion to the polarizing plates 18R, 18G, 18B causes a deterioration in the quality of the image displayed on the screen. When the range is narrowed, dust of 1 to several hundred μm is generated by the spatial light modulators 12R, 12G, 12B and the polarizing plate 17.
It has been found that the adhesion to the R, 17G, 17B and the polarizing plates 18R, 18G, 18B causes deterioration in the quality of the image displayed on the screen. When the range is further narrowed down,
m to several tens of μm of dust are generated by the spatial modulation elements 12R, 12G,
12B, polarizing plates 17R, 17G, 17B, polarizing plate 18
It has been found that the adhesion to R, 18G and 18B causes a decrease in the quality of the image displayed on the screen.

For example, tobacco smoke is usually from 0.01 to
It is considered to have a diameter of about 1 μm. The dust in the room is in the range of one to several hundred μm in diameter. Therefore, when the liquid crystal projector 1 is used in a non-smoking room, it is only necessary to take measures mainly for removing dust.
The main purpose is to remove dust having a diameter of 0 μm (infrared region). As described above, as the charging filter 991, a filter that efficiently collects dust to be collected and does not introduce the dust into the housing 2 is used.

The axial fan (blowing fan) 21 and the blowing fan 24 are also provided on the outer surface of the housing 2 as shown in FIG.
Is provided with a charging filter unit equivalent to the charging filter unit 99 illustrated in FIG. Axial fan (fan for blower) 2
1. The effect of the charging filter unit on the blower fan 24 is the same as that of the charging filter unit 99 on the exhaust fan 25.

From the viewpoint of removing dust, it is most important to remove dust mixed into the outside air taken in from the axial fan (blowing fan) 21, but taken out from the blowing fan 24 and the exhaust fan 25. When dust mixed into the outside air enters the inside of the housing 2, eventually, the polarizing plate 17 </ b> R,
17G, 17B, spatial modulation elements 12R, 12G, 12
B, there is a high possibility of adhesion to the portions of the polarizing plates 18R, 18G and 18B. It is preferable to use what plays.

An axial fan (blowing fan) 21,
It is preferable from the viewpoint of preparing (stocking) a replacement charging filter to use a charging filter having the same specification as a charging filter for the blower fan 24 and the exhaust fan 25.

As described above, according to the first embodiment of the present invention, Japanese Patent Application Laid-Open Nos.
Compared with the liquid crystal projector described in JP-A-00-69396, there is no need to provide a counter electrode and a high-voltage generation circuit applied to the counter electrode, so that the device configuration is simplified and the device can be manufactured at a low price.

Further, according to the first embodiment of the present invention, since the replacement of the charging filter unit 99 or the charging filter 991 is very easy, the operation and maintenance are simple. In other words, JP-A-10-10646 and JP-A-200
As in the method described in Japanese Patent Application Laid-Open No. 0-69396, cleaning of the electrodes is not necessary, and it is very easy to use. As a result, when the projection type display device according to the embodiment of the present invention is used, the charging filter unit 99 or the charging filter 991 is replaced at an appropriate timing, and the quality of the image by the liquid crystal projector device 1 is problematic. Less likely to be.

Charging filter and charging filter unit
Attached to the surface in the form charging filter unit 99 or the charging filter 991 and the housing 2 of the other embodiment of is desirably easy replacement. Representative examples other than those illustrated in FIGS. 3A and 3B are described below. Note that FIG.
(A) and (B) in the following example of a charging filter using an electret corresponding to the charging filter 991;
As in the case of the charging filter 991, an example in which a nonwoven fabric electret of 3M Company, a filterlet S type, or a filterlet G type described above is used will be described.

Second Embodiment of Charging Filter Unit FIGS. 4A and 4B are a sectional view and a perspective view of a charging filter according to a second embodiment. The charging filter unit 201 illustrated in FIGS. 4A and 4B includes a non-woven electret 203 similar to the charging filter 991 shown in FIG. Are fixed by heat welding. That is, in the charging filter unit 201, since plastic is used for the cover 202, the electret 203 in a nonwoven fabric shape can be easily thermally bonded. Since the plastic cover 202 can be manufactured at a low price, the charging filter unit 201 in which the nonwoven fabric electret 203 is heat-welded to the plastic cover 202 can be manufactured at a low price. The burden is small.

This charging filter unit 201 is similar to the charging filter unit 201 shown in FIG.
For example, in the liquid crystal projector device 1 illustrated in FIG.
As illustrated in (A) and (B), the charging filter unit 20 is formed around the cooling air intake 2A formed in the housing 2.
1 is used by being inserted into and removed from the frame 2B which is provided so as to be vertically insertable and removable.

The insertion / removal direction of the charging filter unit 201 with respect to the frame 2B is not limited to the vertical direction, but may be the horizontal direction.

The charging filter unit 2 is mounted on the frame 2B of the housing 2.
When the liquid crystal projector device 1 is operated with the 01 fitted, dust contained in the outside air sucked into the housing 2 from the exhaust fan 25 is collected by the non-woven electret 203, and the dust is contained in the housing 2. No dust is mixed.

The charging filter unit provided before the axial fan (blowing fan) 21 and the blowing fan 24 is the same as described above.

Third Embodiment of Charging Filter Unit FIGS. 6A and 6B are a sectional view and a perspective view of a charging filter according to a third embodiment. The charging filter unit 211 illustrated in FIGS. 6A and 6B is similar to the charging filter unit 211 illustrated in FIGS.
A non-woven electret 213 similar to the charging filter 991 of (B), and the non-woven electret 21
3 (A) and (B) so as to be able to insert and remove
And a cover 212 having a grip portion 214 made of plastic.

The charging filter unit 2 of the third embodiment
Reference numeral 11 denotes a configuration in which, like the charging filter unit 99 according to the first embodiment described with reference to FIGS. The non-woven electret 213 is inserted into and removed from the cover 212 fixed to the cover 2.

When the charging filter unit 211 is detachably screwed to the housing 2, a screw hole is formed around the frame 2 B of the housing 2, and a screw through hole is formed in the grip portion 214. In this case, since the cover 212 is fixed to the housing 2, it is not necessary to make the cover 212 detachable as in the first embodiment described with reference to FIGS. Instead, the cover 212 is fixed to the housing 2.

When the charging filter unit 211 is detachably locked to the housing 2, a locking hole is formed around the frame 2 B of the housing 2, and the holding portion 214 is engaged with the locking hole. Form protrusions. Also in this case, since the cover 212 is fixed to the housing 2, it is necessary to make the cover 212 detachable as in the first embodiment described with reference to FIGS. Instead, the cover 212 is fixed to the housing 2.

Fourth Embodiment of Charging Filter Unit FIG. 7 is a perspective view of a charging filter according to a fourth embodiment. The charging filter unit 221 illustrated in FIG.
A non-woven electret 223 similar to the electrification filter 991 in FIG. 3 and this non-woven electret 223
Is fixed to a cover 222 by a spring holder 224 as a frame 993 of the charging filter unit 99 in FIG. In the charging filter unit 221, since the nonwoven fabric electret 223 is fixed by the spring holder 224, the nonwoven fabric electret 223 can be easily attached to and detached from the cover 222, and the nonwoven fabric electret 223 can be easily replaced. is there.

The charge filter unit 2 of the fourth embodiment
Reference numeral 21 is configured to be screwed or locked to the surface of the housing 2 similarly to the charging filter unit 99 of the first embodiment described with reference to FIGS. 3A and 3B. The method of screwing or locking is the same as the above method.

When exchanging the non-woven electret 223, the entire electrifying filter unit 211 is removed from the housing 2, and the non-woven electret 223 is exchanged by operating the spring holder 224.

Fifth Embodiment of Charging Filter Unit FIG. 8 is a perspective view of a charging filter as a fifth embodiment. The charging filter unit 231 illustrated in FIG.
A non-woven electret 233 similar to the charging filter 991 in FIGS. 3A and 3B and a cover 232 formed by using the non-woven electret 233 as a frame 993 of the charging filter unit 99 in FIG. The electret 233 is fixed to the cover 232 by the holder 234.

As a fixing method, holes are formed in the peripheral portions of the cover 232 and the holder 234, and the cover 232 and the holder 234 are fixed by passing screws through these holes.
The electret 233 arranged between them is fixed.

The charging filter unit 2 of the fifth embodiment
Numeral 21 screws or locks the entire charging filter unit 231 on the surface of the housing 2 similarly to the charging filter unit 99 of the first embodiment described with reference to FIGS. 3A and 3B. The configuration is as follows. The method of screwing or locking is the same as the above method.

When replacing the electret 233,
Remove the screw and remove the charging filter unit 23 from the housing 2.
1 and, simultaneously, cover 232 and holder 234
And separated. In this state, a new nonwoven fabric electret 233 is sandwiched between the cover 232 and the holder 234, and the cover 232 and the holder 234 are fixed while passing screws through holes formed in the cover 232 and the holder 234.
The entire charging filter unit 231 is fixed to the surface of the housing 2.

Sixth Embodiment of Charging Filter Unit FIGS. 9A and 9B are a perspective view of a charging filter according to a sixth embodiment and a partial view illustrating a charged filter mounted state. The charging filter unit 241 illustrated in FIG. 9A has a non-woven electret 243 formed in a knurled shape, and the non-woven electret 243 formed in a lower portion around a rectangular cooling air inlet 2A formed in the housing 2. And a cover 242 fixed to be openable and closable with a hinge (hinge) or the like. The jagged electret 243 is inserted into the rectangular cooling air inlet 2A,
It is fixed to a space between the frame of the exhaust fan 25 (not shown) and the cover 242.

When replacing the electret 243,
The cover 242 is opened, the old electret 243 is taken out, and a new electret 243 is mounted.

The Charging Filter Unit 2 of the Sixth Embodiment
41 uses the cover 242 that opens and closes, so that the electret 243 can be inserted and removed very easily. Further, the charging filter unit 241 according to the sixth embodiment includes:
Since it is jagged as electret 243,
There is an advantage that the performance of substantially collecting dust per unit area is improved.

Seventh Embodiment of Charging Filter Unit FIGS. 10A and 10B are perspective views showing a charging filter according to a seventh embodiment in an opened state and a closed state, respectively. The charging filter unit 251 illustrated in FIGS. 10A and 10B is configured as a bracket dedicated to the filter. The charging filter unit 251 includes:
Bracket 252 for filter and this bracket 2
The cover 25 fixed to the hinge 52 by a hinge 255 so as to be freely opened and closed.
4 and a plurality of non-woven electrets 25 inserted into a plurality of filter insertion portions formed in the bracket 252.
And 3. The bracket 252 and the cover 254 are
The dowel attached to the cover 254 is the bracket 25
It is fixed by inserting it into the hole formed in 2.

The charging filter unit 251 is used, for example, by being attached to and detached from a frame 2B formed around the cooling air intake 2A of the casing 2 as illustrated in FIGS. 5 (A) and 5 (B).

When replacing the electret 253,
The charging filter unit 251 is removed from the frame 2B of the housing 2, the cover 254 is opened from the bracket 252, and only the necessary electret 253 is replaced. afterwards,
The cover 254 is closed, and the charging filter unit 251 illustrated in FIG. 10B is mounted on the frame 2 </ b> B of the housing 2.

The electrification filter unit 251 has an advantage that the electret 253 is divided into a plurality of parts, and only the electret 253 having a reduced collection ability due to dust collection can be replaced.

[0092] Eighth Embodiment FIG. 11 of the charging filter units (A), (B) is a perspective view of a state of attaching the charging filter unit as an embodiment eighth to the housing of the liquid crystal projector device 1, and, It is a partial sectional view. FIG.
1 (A), (B) the charging filter unit 26 illustrated
1 allows the continuous electret 263 mounted on the rewind (rewind) reel 262 to pass through the front surface of the cooling air inlet 2A of the housing 2 of the liquid crystal projector 1,
Take-up (wind-up) reel 2 rotated by a stepping motor 264 as an example of the rotation drive means of the present invention
It is configured to take up at 65. That is, when the stepping motor 264 is rotated, the take-up reel 265 is rotated to rewind the continuous electret 263 mounted on the rewind reel 262, and the fresh electret 263 not used for collection is cooled by the cooling air inlet. It is located in front of 2A. Thus, when the electret 263 on the front surface of the cooling air inlet 2A has a reduced collection performance due to dust collection, the electret 263 having the reduced collection performance can be automatically replaced.

The diameter of the rewind reel 262 mounted on the rewind reel 262 and the take-up reel 26
5, the diameter of the electret 263 wound up changes, so that the electret 2 with respect to the cooling air intake 2A
The position of 63 changes. When the exhaust fan 25 is operating, the electret 263 is sucked into the cooling air inlet 2A by the suction force.
5, the cooling air intake 2A is provided around the cooling air intake 2A so as to prevent outside air from entering the inside of the housing 2 through a gap caused by such a change in the position of the electret 263 with respect to the cooling air intake 2A. A frame 2C of a certain height is provided surrounding the entrance 2A. That is, the cooling air intake 2
Electret 263 located in front of A is always frame 2C
And no gap is created between the cooling air inlet 2A and the outside air. More preferably, the rewind reel 262 usually has the same direction as the take-up reel 265 to prevent the electret 263 from being automatically taken up by the take-up reel 265 biased by the stepping motor 264. Is preferably provided with a spring that rewinds the electret 263 with a reverse force. In other words, the electret 263 is always held by the rewinding force of the electret 263 by the spring of the rewind reel 262, the winding force of the electret 263 by the cooperation of the stepping motor 264 and the take-up reel 265, and the frame 2C having a certain height. , Cooling air inlet 2
It is desirable that some tension is applied so as to close A. These constitute the tension applying means of the present invention.

The stepping motor 264 is configured so that when a switch (not shown) is pressed once, the electret 263 is wound up by the take-up reel 265 by a predetermined length.

Preferably, the liquid crystal projector 1
An airflow detection sensor (not shown) is provided before and after the exhaust fan 25 inside the housing 2 of the housing 2, and a sensor for detecting a dust collection state of the charging filter, for example, a suction airflow of the exhaust fan 25 is determined. The detection value of the air flow detection sensor that detects and indirectly detects the degree of collection of dust adhering to the charging filter is led to a computer or the like built in the liquid crystal projector 1, and the detection value of the air flow detection sensor is reduced to a predetermined value or less. When this happens, the step-up motor 264 can be automatically operated for a predetermined time to automatically rotate the take-up reel 265. As described above, when the decrease in the collection performance of the electret 263 is detected by the air volume detection sensor, the exchange work of the electret 263 is automatically performed, so that the maintenance is easy and the exchange of the electret 263 is appropriately performed. There is an advantage that can be.

Other Embodiments of Charging Filter Unit
The charging filter unit status present invention is not limited to the embodiments described above, the combination of the methods described above, similar to the method described above, and may take various other methods analogy methods described above .

For example, the airflow detection sensor described in the eighth embodiment is also provided in the first to eighth embodiments, and the detection value of the airflow detection sensor is used for the liquid crystal projector 1.
Leads to a computer etc. as an evaluation means built in
When the detection value of the air flow detection sensor in the computer becomes equal to or less than a predetermined value, it is provided, for example, in the operation unit of the liquid crystal projector apparatus 1 that the collection performance of the charging filter unit or the charging filter has deteriorated and it is time to replace the charging filter unit. Can be displayed on the lamp. Thereby, the user of the liquid crystal projector device 1 can know the appropriate replacement timing of the charging filter unit or the charging filter.

Also, the jagged-shaped electret 243 as illustrated in FIG. 9A can be applied to other embodiments to improve the trapping performance per unit area.

Second Embodiment of Projection Display Apparatus The projection display apparatus of the present invention is not limited to the liquid crystal projector apparatus having the structure illustrated with reference to FIGS. 1 and 2, but may be an air-cooled liquid crystal projector having various structures. Applicable to the device.

As another embodiment of the projection type display device of the present invention, a liquid crystal projector device as a second embodiment will be described with reference to FIGS. FIG.
In the color liquid crystal projector device illustrated in FIGS. 2 to 16, the same parts as those of the color liquid crystal projector device 1 according to the first embodiment described with reference to FIGS. FIG. 12 is an external perspective view of a color liquid crystal projector 1A according to the second embodiment, FIG. 13 is a plan view of the same color liquid crystal projector 1A as FIG. 1, and FIGS. 14 to 16 are side sectional views. is there.

The color liquid crystal projector described with reference to FIGS. 1 and 2 has an axial fan (fan for blowing air) 2.
1. Three air cooling fans are provided for each of the blower fan 24 and the exhaust fan 25. In contrast, FIG.
In the color liquid crystal projector 1A according to the second embodiment illustrated in FIGS. 2 to 16, the exhaust fan 25 provided on the outer wall of the housing 2 takes in outside air into the housing 2 as in the above-described embodiment. Further, in the projector device illustrated in FIGS. 12 to 16, a forced air cooling device 31 is provided inside the housing 2, and the discharge lamp 6 is provided by the forced air cooling device 31.
, A PS conversion element 8, and spatial modulation elements 12R, 12G,
Polarizing plate 17 disposed on the entrance side and exit side of 12B
R, 17G, 17B and the polarizing plates 18R, 18G, 18B are configured to be efficiently cooled.

12 to 16, the optical unit 5
Fly-eye lens group 7, PS conversion element 8, mirror 9,
Dichroic mirrors 10R, 10G, three condenser lenses 11R, 11G, 11B, spatial modulation element 12
R, 12G, 12B, cross prism 13, projection lens 14, mirror 15, mirror 16, polarizing plates 17R, 17
G and 17B and the polarizing plates 18R, 18G and 18B are housed inside the optical unit case 4, and the discharge lamp 6 is housed in the lamp box 41 without being housed in the optical unit case 4.

The forced air cooling device 31 incorporates a blower fan 32 in a horizontal and horizontal position almost directly below the projection lens 14 in the lower portion 4 a of the optical unit case 4. The blower fan 32 is provided for the purpose of increasing the amount of cooling air, and uses a multiblade sirocco fan having a high static pressure. A cooling air inlet 32 a of the blower fan 32 is opened at a lower portion of the housing 2. A cooling air outlet 32b is opened laterally below the cross prism 13.

An air duct 33 is provided horizontally below the optical unit case 4. The ventilation duct 33 includes a ventilation start part 33a, a ventilation middle part 33b, and a ventilation termination part 33c. The blower intermediate portion 33b is disposed substantially parallel to the optical axis P2 on which the dichroic mirrors 10R and 10G are disposed. The blowing start end 33a is located immediately below the cross prism 13, and the blowing end 33c
Is disposed substantially parallel to the optical axis P1 where the discharge lamp 6 and the fly-eye lens group 7 are disposed.

One side of the blowing start end 33 a of the blowing duct 33 is connected to the cooling air outlet 32 b of the blowing fan 32, and the upper opening of the blowing start end 33 a is spatially modulated at the lower part of the optical unit case 4. Element 12R, 12G, 1
2B, cooling air outlets 22R,
2G and 22B. An air volume adjusting plate 34 is vertically arranged at a position deviated to the upper side inside the blowing start end 33a. The lower end of the air volume adjusting plate 34 and the air blowing start end 3
A gap 36 is formed between the cooling air outlet 3b and the cooling air outlet 32b of the blowing start end 33a.

An air volume control plate 33d for controlling the air volume of cooling outside air to be blown to the discharge lamp 6 is attached to the air blowing intermediate portion 33b of the air blowing duct 33.

For cooling the color liquid crystal projector 1A, the outside air is forced by the exhaust fan 25 to the forced air cooling device 31.
And the outside air is passed through the ventilation duct 33 to the spatial light modulators 12R, 12G, and 12B, and the polarizing plates 17R and 17R.
This is performed by blowing air to a light modulation portion composed of G, 17B and polarizing plates 18R, 18G, 18B and the discharge lamp 6.

Such a color liquid crystal projector 1
3A, similarly to the liquid crystal projector device 1 of the first embodiment, the outside air flowing into the cooling air inlet 2A formed in the housing 2 located in front of the exhaust fan 25 fixed to the optical unit case 4. 3 (A), (B) to FIG.
By using the same charge filter unit as described with reference to FIGS. 1A and 1B, dust contained in the outside air is collected by the charge filter so as not to be mixed into the optical unit case 4. be able to.

By mounting the charging filter of the present invention on the inner surface of the air duct 33 or the air volume adjusting plate 34, the polarizing plates 17R, 17G, 17B, the spatial light modulators 12R, 12G, 12B, Board 18R, 18
Dust adhering to G, 18B and the like can be collected by the charging filter and prevented from adhering to those portions.

In the color liquid crystal projector 1A described with reference to FIGS.
The above-described charging filter unit may be detachably mounted on the front surface of the cooling air inlet 2A of the housing 2 corresponding to the above-mentioned configuration, so that the number of charging filter units can be reduced, and dust-proof measures are simple. Further, since the number of the charge filter units to be replaced is one, maintenance is easy.

In addition, the color liquid crystal projector 1A illustrated in FIGS. 12 to 16 has a small number of air-cooling fans, so that the overall configuration is simplified and the device configuration can be downsized. Furthermore, the number of air cooling fans is small, so that noise is low.

Second Embodiment of Filter Unit In the above-described embodiment, for example, FIG.
(A), FIG. 4 (A), (B), FIG. 6 (A), (B) to FIG. 11 (A), (B).
When the charging filter is attached to the outer wall of the casing 2 in a replaceable form so as to cover the cooling air intake 2A of the casing 2, when the performance of the charging filter is reduced due to clogging, the charging filter is connected to the outer wall of the casing 2 The case where it is detached and used alone is described. That is, in the above embodiment,
The embodiment has been described in which only the charging filter is used to prevent dust from entering the inside of the housing 2. However, the charging filter of the present invention can be used not only alone as described above, but also in combination with a normal filter, for example, as illustrated in FIGS.

FIGS. 17A and 17B are a perspective view and a sectional view of a filter unit 99A according to a second embodiment of the present invention. FIG. 17C is a cross-sectional view showing a state where the filter unit 99A according to the second embodiment of the present invention is attached to the outer wall of the housing 2 so as to cover the cooling air inlet 2A. The filter unit 99A of the present embodiment includes a first filter 99
0, the second filter 991 and these filters 99
0, 991 and a frame 993 for fixing to the outer wall of the housing 2. Further, between the outer wall of the housing 2 and the suction port of the air-cooling fan, a packing is provided between the outer wall and the air-cooling fan to close the duct and to close the gap between the fan and the duct so as to prevent dust from flowing in. I have. As the second filter 991, the charging filter 991 described in the above embodiment is used. The first filter uses a non-electret filter that is not a charged filter.

Charge filter 99 as second filter
As described above, reference numeral 1 denotes a filter using an electret, which is composed of, for example, two layers of a non-binder polypropylene nonwoven fabric made of microfiber and a reinforcing nonwoven fabric also made of polyproprene, and collects dust. The microfiber layer to be formed is composed of microfibers having a fiber diameter of several μm and produced by a melt-prone method, and each fiber has a permanent charge.

Normal filter 9 as first filter
Reference numeral 90 denotes a non-electret filter that does not use an electret unlike the charging filter 991 described above. Such a non-electret filter 990
For example, as in the case of the charging filter 991, there are two types of binderless nonwoven polyproprein nonwoven fabric made of microfibers and polypropylene nonwoven fabric for reinforcement.
The microfiber layer that collects dust is made by the melt-prone method. The fiber diameter is several μm.
Microfiber. However,
Unlike the charging filter 991, it is not made so that each fiber has a permanent charge.

The non-electret filter 990 is
When the filter unit 99A is attached to the outer wall of the housing 2, the cooling air inlet 2A
Is attached to the frame 993 at a position located in front of the charging filter 991 with respect to the flow A of air (outside air) sucked into the housing 2 from the inside. The reason is that first, dust is collected by the non-electret filter 990, and as much as possible,
This is to reduce dust reaching the charging filter 991. By doing so, the charging filter 991
Clogging can be delayed.

Of course, it is necessary to prevent the overall dust collecting effect from being reduced when the non-electret filter 990 and the charging filter 991 are used in combination. For this purpose, the charging filter 991 having the above-described performance, for example, a filter capable of collecting dust having a diameter of 1 to several hundred μm (infrared region) is used.
As the non-electret filter 990, a filter having a performance of collecting dust having a diameter larger than that is used. That is, as the non-electret filter 990, a filter having a coarser mesh for collecting dust than the charging filter 991 is used. For example, similarly to the charging filter 991, the non-electret filter 990 is formed of two layers of a non-binder polypropylene nonwoven fabric made of microfiber and a reinforcing nonwoven fabric also made of polyproprene, and has a microscopic structure for collecting dust. Although the fiber layer is formed of microfibers having a fiber diameter of several μm and made by a melt-prone manufacturing method, the spacing between the fibers, that is, the spacing between the stitches is set wider than the charging filter 991. The same effect can be obtained with multiple layers of the charging filter.

As described above, the non-electret filter 990 is made of a non-woven fabric, and can remove clogged dust by suction with a vacuum cleaner while the non-electret filter 990 is attached to the filter unit 99A. Is preferred. Alternatively, it is preferable that the filter unit 99A be detached from the housing 2, the non-electret filter 990 be detached from the filter unit 99A, and the filter unit be washed and used repeatedly. By doing so, the non-electret filter 990 can be used continuously, and the non-electret filter 990 is frequently replaced to remove the clogged dust as described above, and the entire filter unit 99A is removed. High dust removal performance can be maintained.

In this embodiment, the charging filter 9
When the amount of clogging of the filter 91 increases and the dust removal performance of the charging filter 991 itself decreases, the charging filter 991
Replace and discard. However, in the present embodiment, since the non-electret filter 990 is provided at the front stage to prevent large dust from reaching the charging filter 991, the life of the charging filter 991 can be substantially extended. it can. Charge filter 99
1, the non-electret filter 990
Since the price is low, from the viewpoint of operation / price, using the filter unit 99A of the present embodiment using the non-electret filter 990 increases the operation / price ratio of the projection display device.

The filter unit 99A described with reference to FIGS. 17A to 17C, that is, the charging filter 991
The filter unit 99A provided with the non-electret filter 990 at the preceding stage is not limited to the configuration of FIGS. 3A and 3B, but may have other configurations, for example, FIGS. 4A and 4B.
) And FIGS. 6 (A) and 6 (B) to FIGS. 11 (A) and 11 (B). That is, a non-electret filter is provided in front of the charging filter, and FIGS. 4 (A), (B), FIG.
When a filter unit similar to the filter unit illustrated in FIGS. 11 (B) to 11 (A) and 11 (B) is configured and arranged in front of the cooling fan of the projection display device, the same effects as described above are achieved. be able to.

The embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made.

[0122]

The projection type display device using the charging filter unit of the present invention has a high dust collecting performance, and can display a high quality image for a long time with high reliability. In particular, when a charging filter having an appropriate collection performance is used, dust to be maintained can be appropriately collected and prevented from entering the inside of the housing.

The charging filter unit of the present invention is disclosed in JP-A-10-10646 and JP-A-2000-6939.
Unlike the case of using the electrode in Japanese Patent Application Laid-Open No. 6-64, there is no need to perform an operation such as an operation of removing dust attached to the electrode. Since the charging filter unit of the present invention is mounted on the projection display device so that it can be easily replaced, maintenance and operation of the projection display device are facilitated.

In particular, when a non-electret filter is disposed in front of the charging filter, and the charging filter and the non-electret filter are combined to form a filter unit for use in a projection display device, the charging filter becomes clogged. And the cooling effect can be maintained for a long period of time.

Since the charging filter unit of the present invention can be manufactured at a low price, even if it is replaced when the dust collecting performance is reduced, the economic burden is low.

The filter unit in the projection type display device of the present invention does not require a counter electrode, a high voltage generating circuit, etc., and can be reduced in size.

[Brief description of the drawings]

FIG. 1 is a plan view of a liquid crystal projector device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional configuration diagram of the liquid crystal projector device illustrated in FIG.

FIG. 3 is a partial external view illustrating an attached state of an exhaust fan and an attached state of a charging filter unit of the first embodiment in the liquid crystal projector device illustrated in FIGS. 1 and 2;

FIGS. 4A and 4B are a cross-sectional view and a perspective view of a charging filter according to a second embodiment.

FIGS. 5A and 5B are partial external views illustrating an attached state of an exhaust fan and an attached state of a charging filter unit of the second embodiment in the liquid crystal projector device illustrated in FIGS. 1 and 2; FIG.

FIGS. 6A and 6B are a cross-sectional view and a perspective view of a charging filter according to a third embodiment.

FIG. 7 is a perspective view of a charging filter according to a fourth embodiment.

FIG. 8 is a perspective view of a charging filter according to a fifth embodiment.

FIGS. 9A and 9B are a perspective view of a charging filter according to a sixth embodiment and a partial view illustrating a state in which the charging filter is mounted.

FIGS. 10A and 10B are perspective views of a charging filter according to a seventh embodiment in an open state and a closed state, respectively.

FIGS. 11A and 11B are a perspective view and a partial cross-sectional view of a charging filter unit according to an eighth embodiment.

FIG. 12 is a perspective view of a liquid crystal projector as a second embodiment of the present invention.

FIG. 13 is a plan view of the color liquid crystal projector illustrated in FIG.

FIG. 14 is a side sectional view of the color liquid crystal projector illustrated in FIG. 13;

FIG. 15 is another side sectional view of the color liquid crystal projector illustrated in FIG. 13;

FIG. 16 is still another side sectional view of the color liquid crystal projector illustrated in FIG. 13;

FIGS. 17A to 17C are perspective views, cross-sectional views, and projection type display devices of a filter unit illustrating a case where the filter unit according to the second embodiment is applied to a projection type display device. FIG.

[Explanation of symbols]

 1, 1A color LCD projector device 2 housing 2A cooling air inlet 2B frame 2C frame 3 stand 4 optical unit case 5 optical unit 6 discharge lamp 7 ··· Fly eye (fly's eye) lens group 8 ··· PS conversion element 9 ··· Mirror 10R, 10G ··· Dichroic mirror 11R, 11G, 11B ··· Condenser lens 12R, 12G, 12B ··· Spatial modulation element 13 ··· Cross prism 14. Projection lens 15, 16 Mirror 17R, 17G, 17B Polarizer 18R, 18G, 18B Polarizer 21 Axial fan (fan) 22R, 22G, 22B Cooling Air outlets 23R, 23G, 23B ··· Cooling air outlets 24 · · Fans for air blow 25 · · Fans for exhaust 31 · · Forced air cooling device 32 · Blower fan 32a Cooling air inlet 32b Cooling air outlet 33 Ventilation duct 34 Airflow regulating plate 38 Cooling air outlet 39 Cooling air outlet 99 Charging filter unit 99A ..Filter unit 990..Non-electret filter 991..Charging filter, 993..Frame 201..Charging filter unit 202..Cover, 203..Electret 211..Charging filter unit 212..Cover, 213 .. Electret 214 ... gripping part 221 charging filter unit 222 cover 223 electret 224 spring holder 231 charging filter unit 232 cover 233 electret 234 holder 241 charging Filter unit 242・ Cover, 243 ・ ・ Electret 251 ・ ・ Charge filter unit 252 ・ ・ Bracket ・ 253 ・ ・ Electret 254 ・ ・ Cover 261 ・ ・ Charge filter unit 262 ・ ・ Rewind reel 263 ・ ・ Electret 264 ・ ・ Stepping motor 265 ・ ・ Take Up reel

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Nobuhiko Nishiko, Inventor 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Nobuaki Higuchi 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo No. Sony Corporation F term (reference) 2H088 EA12 HA13 HA21 HA23 HA24 HA28 MA16 MA20 2H089 HA40 QA06 QA08 QA12 TA12 TA16 TA17 TA18 UA05

Claims (17)

[Claims] 1. A projection display device for cooling externally said lighting means and / or said light modulating means by taking in outside air into a housing in which said lighting means and said light modulating means are accommodated. A projection display device provided with a charging filter using a dielectric material that maintains permanent polarization. 2. An air cooling fan for introducing the outside air into the housing is provided inside the housing, and the charging filter is provided on an outer surface of the housing located outside a position where the air cooling fan is provided. The projection-type display device according to claim 1, wherein the projection-type display device is provided in: 3. The projection display device according to claim 2, wherein said charging filter is exchangeably mounted from outside of said housing. 4. The projection display device according to claim 1, wherein said charging filter is a charging filter that effectively collects dust of about 1 to several tens of μm. 5. The air cooling fan is provided in an optical unit case provided inside the housing, an outside air intake opening is provided in a surface of the housing, and the outside air intake opening is operated by the operation of the air cooling fan. The projection display device according to any one of claims 1 to 3, wherein outside air is introduced into the housing via the housing. 6. The projection type display device according to claim 5, wherein a frame is provided outside the housing around the outside air intake opening formed in the housing so that the charging filter can be inserted and removed. 7. A charging filter unit comprising a cover and a non-woven electret fixed to the cover, wherein a screw hole is formed around the outside air intake opening formed in the housing. The projection display device according to claim 5, wherein the projection display device is detachably fixed to the housing via a housing. 8. A lock hole is formed around the outside air intake opening formed in the housing, and a cover and a non-woven electret fixed to the cover are provided. 6. The projection display device according to claim 5, wherein a charging filter unit having a mating projection is detachably fixed to the housing via the locking hole. 9. The projection type display device according to claim 1, wherein said charging filter is formed so as to be jagged so as to increase an effective dust collecting area per unit area. 10. The projection type display device according to claim 1, wherein said charging filter is divided into a plurality of parts and is replaceable. 11. The projection type according to claim 5, wherein said charging filter is formed continuously, and said continuous charging filter is movable on a front surface of said outside air intake opening provided on a surface of said housing. Display device. 12. The apparatus according to claim 1, further comprising: a sensor for detecting a state of collecting dust in said charging filter; and evaluation means for evaluating a state of collecting dust in said charging filter in accordance with a reading of said sensor. Projection display device. 13. A continuous winding filter, comprising: a rewind reel; a take-up reel; and a rotation drive means for rotating the take-up reel. The used part is loaded on the rewind reel, and the used part is wound up on the take-up reel. 13. The projection type display device according to claim 12, wherein said rotation driving means is driven, and said rotation driving means rotates said take-up reel such that said charging filter is wound up by said take-up reel for a predetermined length. 14. The charging filter loaded between the rewind reel and the take-up reel is configured to substantially close the outside air intake opening on the surface of the housing with a predetermined tension. 2. The projection display device according to claim 1, further comprising a tension applying unit. 15. A non-electret filter which has a performance of collecting larger dust than the charge filter without using a dielectric that maintains permanent polarization in front of the charge filter and adjacent to the charge filter. The projection display device according to claim 1, further comprising: 16. The non-electret filter,
The projection display device according to claim 15, wherein the projection display device is exchangeably mounted. 17. The non-electret filter,
The projection display device according to claim 15, wherein the projection display device is washable.