JP2016080873A - Image projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image projection device that allows removal of dust from not only a light valve but also a peripheral optical part of the light valve at the time of dust removal (second mode).SOLUTION: The image projection device includes: a light valve; a prism; an optical element between the light valve and the prism; a projection optical system; and a blower fan blowing air introduced from an inlet port of the device body to at least one cooling target of the light valve, the prism, and the optical element, the blower fan being operable in a first mode for cooling and a second mode for dust removal, the first mode being for blowing air to a cooling target via a first filter in an air channel extending from the inlet port to the cooling target capable of removing dust of a first size or larger, and the second mode being for blowing air to the cooling target via a second filter in the air channel extending from the inlet port to the cooling target capable of removing dust of a second size or larger, the second size being smaller than the first size.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image projection apparatus, and more particularly to an apparatus capable of removing dust from a light valve (such as a reflective liquid crystal display element) and peripheral optical components.

  2. Description of the Related Art Conventionally, there is known a projection type image display apparatus having means for removing dust attached to a light valve by setting a special mode such as a dust removal mode for the dust attached to the light valve. Patent Document 1 discloses an example of removing dust adhering to a light valve by having means for increasing the air flow rate with respect to the light valve more than that during cooling when the dust removal mode is set.

JP 2005-77891 A

  However, in the prior art disclosed in the above-mentioned patent document, it is necessary to use air that does not include dust in order to prevent dust from being removed and reattached by air in the dust removal mode. The fine filter has a large pressure loss, and it is necessary to increase the air volume of the fan or the like. If the fine air intake filter is arranged even in the normal cooling mode state, there arises a problem that noise accompanying the increase of the air volume of the fan occurs.

  In the prior art disclosed in the above-mentioned patent document, in order to remove dust from the light valve by increasing the wind speed of the air flow during the dust removal mode, It is difficult to remove.

  An object of the present invention is to provide a projection image apparatus that can also remove dust from a light valve and optical components around the light valve during dust removal (second mode).

  To achieve the above object, an image projection apparatus according to the present invention includes a light valve, a prism for branching or synthesizing an optical path, an optical element provided in the optical path between the light valve and the prism, and a projection target. A projection optical system for projecting a light beam from the light valve onto a surface, and at least one of the light valve, the prism, and the optical element is configured to receive wind sucked from an air inlet of the apparatus main body. It has a blower fan that blows air toward one cooling object, and is operable in a first mode for cooling and a second mode for removing dust. In the first mode, the air intake port of the apparatus main body The air is blown to the object to be cooled through the first filter that is disposed in the air path from the object to the object to be cooled and can remove dust of the first size or larger, and in the second mode, Air is blown to the object to be cooled through a second filter disposed in an air passage extending from the air inlet of the main body to the object to be cooled and capable of removing dust of a second size or larger smaller than the dust of the first size. It is characterized by.

  According to the present invention, it is possible to provide a projection image apparatus capable of removing dust from the light valve and optical components around the light valve during dust removal (second mode).

It is a main block diagram of the ventilation system at the time of normal use in the 1st Embodiment of this invention. It is sectional drawing of the ventilation system at the time of normal use in the 1st Embodiment of this invention. It is a state figure of the 1st step (dust removal mode 1) of the 2nd mode. It is sectional drawing in the state of the 1st step (dust removal mode 1) of 2nd mode. It is a state figure of the 2nd step (dust removal mode 2) of the 2nd mode. It is sectional drawing in the state of the 2nd step (dust removal mode 2) of 2nd mode. It is a flowchart regarding operation | movement of 1st Embodiment. 1 is a schematic diagram of an optical configuration of an image projection apparatus according to an embodiment of the present invention. It is a main block diagram of the ventilation system at the time of normal use in the 2nd Embodiment of this invention. It is sectional drawing of the ventilation system at the time of normal use in 2nd Embodiment. It is a state figure of the 2nd mode (dust removal mode) in a 2nd embodiment. It is sectional drawing in the state of the 2nd mode (dust removal mode) in 2nd Embodiment. It is a flowchart regarding operation | movement of 2nd Embodiment. It is a figure explaining arrangement | positioning of the 1st filter in the apparatus main body of the image projection apparatus which concerns on embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<< First Embodiment >>
(Image projection device)
FIG. 8 is a schematic optical configuration diagram of a projector which is an image projection apparatus according to an embodiment of the present invention. The light source unit 5 is a high-intensity light source such as an ultra-high pressure mercury lamp, and includes an arc tube that emits white light in a continuous spectrum, and a reflector that condenses the light in a predetermined direction. Irradiate toward 6. The illumination optical system 6 has a glass member such as a cylinder array, and by its optical action, a rectangular uniform illumination area in which rectangular images are superimposed on a plurality of light beams is formed, and the next stage color separation The optical unit 1 that is a combining optical system is illuminated.

  The optical unit 1 includes a dichroic mirror 1001 that reflects light in the blue (B) and red (R) wavelength regions and transmits light in the green (G) wavelength region. For light in the green (G) wavelength region, there is a half-wave plate 1002, a G-use incident side polarizing plate 1003 with a polarizing element attached to a transparent substrate that transmits only S-polarized light, and a polarization separation surface. A first polarization beam splitter 13G that transmits P-polarized light and reflects S-polarized light is provided.

  The S-polarized light reflected by the first polarizing beam splitter 13G serving as a prism that branches the optical path is converted to circularly polarized light via the green quarter-wave plate 12G, and is placed on the heat sink 112G. Head to light valve 111G. The quarter-wave plate 12G is provided in the optical path between the first polarizing beam splitter 13G and the green light valve 111G.

  The light reflected by the green light valve 111G is converted to P-polarized light through the green quarter-wave plate 12G. Then, the light passes through the first polarizing beam splitter 13G and the G exit-side polarizing plate 1010G that transmits only the P-polarized light, and travels toward the dichroic prism 1011 that transmits the RB light and reflects the G light.

  For R and B light reflected by the dichroic mirror 1001, an RB incident side polarizing plate 1006 and a color selective phase difference plate 1007 that transmit only P-polarized light and have a polarizing element attached to a transparent substrate are provided. It has been. The color-selective retardation plate 1007 has a function of converting the polarization direction of the R light by 90 degrees and not converting the polarization direction of the B light, so that light in the red (R) wavelength region is converted to S-polarized light. , Light in the blue (B) wavelength region passes through with P polarization. A trimming filter 1008 for returning orange light to the lamp is provided in the optical path that has passed through the color selective phase difference plate 1007 in order to increase the color purity of R.

  The second polarization beam splitter 13BR as a prism that transmits the P-polarized light, reflects the S-polarized light, and branches or combines the optical path reflects the S-polarized R light while the P-polarized B light. Is transparent. The R light reflected by the second polarizing beam splitter 13BR is circularly polarized through the red quarter-wave plate 12R and travels toward the red light valve 111R placed on the heat sink 112R. The light reflected by the red light valve 111R is converted to P-polarized light via the red quarter-wave plate 12R.

  Then, the light passes through the second polarizing beam splitter 13BR, the B output side polarizing plate (polarizing element) 1010B that rectifies only the S-polarized light of B, and the dichroic prism 1011 and enters the projection lens 7 as the projection optical system.

  On the other hand, the B light transmitted through the second polarizing beam splitter 13BR is circularly polarized through the blue quarter-wave plate 12B, and travels toward the blue light valve 111B placed on the heat sink 112B. . The light reflected by the blue light valve 111B is converted to P-polarized light through the blue quarter-wave plate 12B. Then, the light is reflected by the second polarizing beam splitter 13BR, passes through the B-use exit side polarizing plate (polarizing element) 1010B that rectifies only the S-polarized light of B, and passes through the dichroic prism 1011 and enters the projection lens 7 as the projection optical system. Incident.

  The red light valve 111R, the green light valve 111G, and the blue light valve 111B, which are reflective liquid crystal display elements, reflect incident light and modulate the image. Then, by using the above-described color separation / synthesis optical system, the images on the light valves 111R, 111G, and 111B are projected as color images onto the projection surface (screen surface) by the projection lens 7.

(First mode for cooling, second mode for dust removal)
A projector that is an image projection apparatus according to an embodiment of the present invention is a first mode for cooling and dust removal by a blower system (provided in a direction perpendicular to the paper surface of FIG. 8) including a blower fan (hereinafter referred to as a fan). In the second mode.

  In the first mode, the fan serves as a cooling fan to cool at least one of the light valve 111, the quarter wavelength plate 12, and the polarization beam splitter 13 (more preferably, the light valve 111 or the quarter wavelength plate 12). Cool as a target. In the second mode, the fan sends wind to at least one of the light valve 111, the quarter wavelength plate 12, and the polarization beam splitter 13 as a dust removal fan.

Here, in the first mode, a first filter 50 (FIG. 14) capable of removing dust of a size equal to or larger than the first size is provided at the intake port (main body intake port) of the apparatus main body. However, in the first mode, the second filter 31 that can remove dust of a second size or larger that is smaller than the first size of dust is not used. Note that the sizes of the first and second sizes of dust indicate the diameter of the dust. The second filter 31 is provided at the inlet 211 of the fan 21 (downstream from the inlet of the apparatus main body) only in the second mode. Used. In the second mode, the second filter 31 is used together with the first filter 50.

  In FIG. 14, the air inlet of the apparatus main body 100 (the air inlet of the apparatus main body) is an air blowing system (an optical unit 1, an air guide unit 2, a filter unit 3) described later for the light valve 111, the optical element 12, and the prism 13. Is provided at a position where the first filter 50 is in close contact with the upstream side.

(Blower system)
Hereinafter, an air blowing system including a fan related to the first mode and the second mode will be described with reference to FIGS. 1 to 7. The blower system shown in FIG. 1 includes an optical unit 1, an air guide unit 2, and a filter unit 3. As described above, the optical unit 1 includes the light valve 111, the light valve unit 11 including the heat sink 112, the quarter-wave plate 12 as an optical element, and the prism 13 as a polarization beam splitter.

  The air guide section 2 includes a fan 21 and a duct 22 as a first air path forming member (air guide wall) that forms an air path from the fan 21 to the light valve unit 11 and the quarter-wave plate 12. Moreover, it has the duct 23 as a 2nd wind path formation member (wind guide wall) guide | induced to the prism 13 direction as a ventilation destination from the fan 21. FIG. In addition, a motor 24 is provided for switching between the duct 22 and the duct 23.

  The filter unit 3 has dust (the second size described above) existing in the wind from the upstream side where the fan 21 sucks from the air inlet 211 of the fan 21 (the first filter removes dust larger than the first size). It has the 2nd filter 31 which removes (collects) the above dust. The filter unit 3 includes a holding unit 32 that holds the second filter 31 and a guide unit 33 that guides the holding unit 32 to the air inlet 211 of the fan 21. A motor (not shown) necessary for driving the guide portion 33 is provided.

  Next, the operation of the blower system will be described. FIG. 1 shows the state of the blower system in the normal use state of the projector (first mode for cooling). 2 shows a cross-sectional view of a plane parallel to the direction of the cooling air in FIG. 1 showing the first mode for cooling. As shown in FIGS. 1 and 2, the fan 21 takes in air inside the projector located upstream from the air inlet 211 from the air inlet 211 and blows it out toward the optical unit 1 from the air outlet 212.

  In FIG. 2, the air (wind) blown out from the fan 21 is directed to the light valve 111 and the heat sink 112 that efficiently dissipates the heat quantity of the light valve 111 by the air guide shape formed by the duct 22 and a part of the duct 23. (Air flow 41, 42). The air (wind) guided by the duct 22 branches into an air flow 41 that flows on the heat sink 112 side and an air flow 42 that flows between the light valve 111 and the holding member 14 that holds the quarter-wave plate 12. The light valve 111 and the quarter wave plate 12 are cooled.

  At this time, when the dust (second size or larger dust that is not removed by the first filter described above) mixed in the projector housing is sucked by the fan 21 and mixed around the optical unit 1, the following phenomenon occurs. That is, it adheres to the surfaces of the light valve 111, the quarter-wave plate 12, and the prism 13 by a specific adhesion force such as gravity or electrostatic force, and this can be visually recognized as a projection image.

  The projector according to the present embodiment includes a blower system that starts the second mode (dust removal mode) in response to a user input in order to remove the attached dust as described above, and the second mode automatically when the power is turned off. Has a blower system to start.

(flowchart)
FIG. 7 is a flowchart regarding the operation of the air blowing system (dust removal system) in the second mode. When the dust removal mode (second mode) is set by the user's input from the normal use state (first mode) shown in FIGS. 1 and 2, or when the projector is turned off, the blower system in the second mode is automatically set. Start (when the device is off).

  First, it is determined whether there is an operation to turn off the power. If there is no operation to turn off the power, the amount of light entering the optical unit 1 is reduced, and the cooling air from the fan 22 has not reached. However, the temperature is set so that the performance of the light valve 111 and the quarter-wave plate 12 is satisfied. When there is a dimming state or an operation to turn off the power, the second filter 31 is arranged in a form in which the air inlet (fan inlet) 211 of the fan 21 is sealed (FIG. 3).

  The second filter 31 is integrated with the holding portion 32, the holding portion 32 has a thread on the outer portion, and a rod-like screw is disposed on one side of the guide portion 33 that engages with the holding portion 32. When the rod-shaped screw is rotated by a motor (not shown), power is transmitted to the thread of the outer portion of the holding portion 32, and the second filter 31 is disposed at the intake port 211. FIG. 3 shows a state in which the second filter 31 is arranged at the intake port 211, and FIG. 4 shows a cross-sectional view of a plane parallel to the cooling air direction in FIG. The second filter 31 is one that removes (collects) dust having a particle size of 30 μm or less (more preferably 20 μm or less).

  Next, whether or not dust is attached to the light valve 111 and the quarter-wave plate 12 is read by a sensor as dust attachment detection means arranged in the vicinity of the optical unit 1. At this time, the particle size for detecting dust adhering to the light valve 111 and the quarter-wave plate 12 is 20 μm or less.

  When dust is attached, the output of the fan 21 is amplified in the state of FIG. 3 using the duct 22 as the dust removal mode 1 (first stage in the second mode). As a result, the flow velocity of the air flow 42 shown in FIG. 4 is increased (the amount of blown air is increased), and dust adhering to the light valve 111 and the quarter-wave plate 12 is removed.

  After completion of the dust removal mode 1 or when the sensor reads that no dust is attached to the light valve 111 and the quarter-wave plate 12, dust is attached to the prism 13 by the sensor disposed in the vicinity of the optical unit 1. Read if not. At this time, the particle diameter for detecting dust adhering to the prism 13 is 100 μm or less.

  When dust is attached to the prism 13, the dust removal mode 2 (second stage in the second mode) is started. FIG. 5 shows a main configuration diagram in the dust removal mode 2, and FIG. 6 shows a cross-sectional view of a plane parallel to the air direction of the air (wind) in FIG. In the dust removal mode 2, the duct 23 is rotated by the motor 24 (the state shown in FIG. 5), and air (wind) from the air outlet 212 of the fan 22 is held by the holding unit 12 that holds the prism 13 and the quarter-wave plate 12. (Air flow 43 in FIG. 6). The duct 23 is disposed after a certain time after the second filter 31 is disposed.

  Thereafter, the output of the fan 21 is amplified, the flow velocity of the air flow 43 is increased, and dust adhering to the prism 13 and the prism 13 side of the quarter wavelength plate 12 is removed. After completion of the dust removal mode 2, as shown in FIG. 7, is dust attached to the light valve 111 and the quarter-wave plate 12 by a sensor as dust adhesion detection means such as a camera disposed in the vicinity of the light source unit 1? Give feedback to the reading operation.

  When it is read that no dust is attached to the prism 13, the output of the fan 21 is set to the normal use state, and the second filter 31 arranged in FIG. 3 is arranged in the state of FIG. 1 (to the first mode). Preparation). After returning the second filter 31 to the state of FIG. 1 (in this state, the first filter is effectively present and removes dust of the first size or larger), there is no operation to turn off the power before starting the blower system. If it is, the dimming state is cancelled, and after the dimming state is cancelled, the blower system is terminated. In addition, after returning the 2nd filter 31 to the state of FIG. 1, when there exists operation which turns off a power supply, a ventilation system is complete | finished.

  In the present embodiment, even when the cooling air from the fan 22 has not reached, the light enters the optical unit 1 in order to achieve a temperature state that satisfies the performance of the light valve 111 and the quarter-wave plate 12 (suppresses heat generation). Although the amount of incident light is reduced, the present invention is not limited to this. For example, a means for suppressing power consumption of the light valve 111 itself may be used, or a light reduction means and a power consumption suppression means may be used in combination.

(Effect of this embodiment)
With the above-described configuration and operation, in this embodiment, dust attached to the light valve 111, the quarter-wave plate 12, and the prism 13 can be removed in the second mode. And it can prevent that dust adheres again in the state of the 1st, 2nd stage (dust removal modes 1 and 2) of the 2nd mode under removal. This is because the switching between the first stage and the second stage is continuous.

  Further, the second filter 31 is disposed at the air inlet 211 of the fan 21 only when the second mode (dust removal mode) is started. For this reason, in the normal use state (the first mode in FIG. 1), the second filter 31 as the second filter can be eliminated, and the output (for example, the rotational speed) of the fan 22 can be reduced as compared with the second mode. Can be quiet.

  As described above, in the present embodiment, the noise is reduced during normal cooling (first mode), and the dust of the light valve and optical components around the light valve can be removed during dust removal (second mode). The projected image apparatus can be provided.

<< Second Embodiment >>
Hereinafter, with reference to FIG. 9 thru | or FIG. 13, the ventilation system which concerns on the 2nd Embodiment of this invention is demonstrated. In the first embodiment, with respect to the filter unit, the displacement direction of the second filter to the intake port in the second mode (dust removal mode) is the in-plane direction of the intake port, whereas in this embodiment, the second direction The difference is that the direction of displacement of the filter toward the intake port is the out-of-plane direction of the intake port. The outline of the optical configuration of the projector having the air blowing system according to this embodiment is the same as that of the first embodiment.

  FIG. 9 is a main configuration diagram of the air blowing system in the present embodiment, and includes the optical unit 1, the air guide unit 200, and the filter unit 300. The optical unit 1 has the same configuration as that of the first embodiment. The air guide section 200 includes a fan 21 and a duct 22 as a first air path forming member (air guide wall) that forms an air path from the fan 21 to the light valve unit 11 and the quarter-wave plate 12. Moreover, it has the duct 23 as a 2nd wind path formation member (wind guide wall) guide | induced to the prism 13 direction as a ventilation destination from the fan 21. FIG. In addition, a motor 24 is provided for switching between the duct 22 and the duct 23.

  The filter unit 300 has dust (dust of the second size or larger described above) existing in the wind from the upstream side where the fan 21 sucks from the air inlet 211 (the first filter removes dust of the first size or larger). ) Is removed (collected). In addition, the filter unit 300 includes a second filter 31 that collects wind dust sucked by the blower fan 21 and a holding unit 34 that holds the second filter 31. A motor (not shown) necessary for driving the guide portion 33 is provided.

  Next, operation | movement of the ventilation system in this embodiment is demonstrated. FIG. 9 shows a state of the blower system in the normal use state (first mode) of the projector of the present embodiment. FIG. 10 shows a cross-sectional view of a plane parallel to the air direction of the air (wind) in FIG.

  As shown in FIGS. 9 and 10, the fan 21 is not removed by the first filter that removes dust mixed in the housing of the projector from the air inlet 211 (dust of the first size or more provided on the upstream side of the air inlet 211. Dust larger than the size) is sucked by the fan 21. When the dust mixed in the projector housing is sucked by the fan 21 and mixed around the optical unit 1, the following phenomenon occurs. That is, it adheres to the surface of the light valve 111, the quarter wavelength plate 12, and the prism 13 by a specific adhesion force such as gravity or electrostatic force, and can be visually recognized as a projection image.

  For this reason, in the second mode (dust removal mode), the second filter 31 is provided at the intake port 211. Then, the air inside the projector is sucked through the second filter 31 and blown out from the blowout port 212 toward the optical unit 1.

  In FIG. 10, the air blown from the fan 21 is directed toward the light valve 111 and the heat sink 112 that efficiently dissipates the heat quantity of the light valve 111 by the air guide shape formed by the duct 22 and a part of the holding member 34. The air is guided (air flow 410, 420). The air guided by the duct 22 branches into an air flow 410 flowing on the heat sink 112 side and an air flow 420 flowing between the light valve 111 and the holding member 14 holding the quarter-wave plate 12, and the light valve 111. Then, the quarter-wave plate 12 is cooled (first mode).

  The projector according to the present embodiment includes the second mode for removing the attached dust as described above. And it has the system which starts 2nd mode by a user's input, and the system which starts 2nd mode automatically, when turning off a power supply. Regarding such a dust removal system, FIG. 13 shows a flowchart of the operation of the dust removal system in the second mode.

  First, in the normal use state (first mode) shown in FIGS. 9 and 10, the second mode is automatically started when the user inputs and sets the second mode or turns off the projector. It is determined whether or not there is an operation to turn off the power, and if there is no operation to turn off the power, the amount of light entering the optical unit 1 is reduced, and even if the cooling air from the fan 22 has not reached, the light valve The temperature is set to satisfy the performance of the 111 and ¼ wavelength plates 12.

  When there is a dimming state or an operation to turn off the power, the second filter 31 is arranged so that the air inlet 211 of the fan 21 is sealed. FIG. 11 shows a state in which the second filter 31 is arranged at the inlet 211 portion, and FIG. 12 shows a cross-sectional view of a plane parallel to the direction of the cooling air in FIG. The second filter 31 is integrated with the holding portion 34, and the joint between the holding portion 34 and the duct 22 is rotated by the motor 24 in the out-of-plane direction of the intake port 211. Placed in.

  At the same time, the holding unit 34 has a wind guide shape leading to the light valve 111 and the quarter-wave plate 12 and the prism 13, so that the air flow 440 flowing between the light valve 111 and the quarter-wave plate 12 is generated. Generate. Further, an air flow 430 that flows between the quarter-wave plate 12 and the prism 13 is generated.

  Thereafter, by amplifying the output of the fan 21, the flow velocity of the airflows 430 and 440 is increased, and dust adhering to the light valve 111, the quarter wavelength plate 12, and the prism 13 is removed. The second filter 31 is used to remove (collect) dust having a particle size of 20 μm or less.

  Next, a sensor as dust adhesion detection means such as a camera disposed in the vicinity of the optical unit 1 reads whether dust is adhered to the light valve 111, the quarter wavelength plate 12, and the prism 13. At this time, the particle diameter for detecting dust attached to the light valve 111 and the quarter-wave plate 12 is 20 μm or less, and the particle diameter for detecting dust attached to the prism 13 is 100 μm or less.

  As a result of reading the dust adhesion, as shown in FIG. 13, the output of the fan 21 is amplified and the output amplification of the fan 21 and the sensor detection are repeated until the dust can be removed as shown in FIG. When it is read that dust is not attached, the output of the fan 21 is set to the normal use state, and the second filter 31 and the holding unit 34 are arranged in the state of FIG. 9 by the motor 24 (preparation for the first mode).

  After returning the second filter 31 as the second filter to the state shown in FIG. 9 (in this state, the first filter is effectively present and removes dust of the first size or larger), and before starting the blower system, the power supply If there is no action to turn off, do as follows. That is, after the dimming state is canceled and the dimming state is cancelled, the blower system is terminated. In addition, after returning the 2nd filter 31 to the state of FIG. 1, when there exists operation which turns off a power supply, a ventilation system is complete | finished.

  In the present embodiment, even when the cooling air from the fan 22 has not reached, the amount of light entering the optical unit 1 is set to a temperature state that satisfies the performance of the light valve 111 and the quarter-wave plate 12. Although fading, it is not limited to this. For example, a means for suppressing power consumption of the light valve 111 itself may be used, or a light reduction means and a power consumption suppression means may be used in combination.

(Effect of this embodiment)
With the above-described configuration and operation, in this embodiment, dust attached to the light valve 111, the quarter-wave plate 12, and the prism 13 can be removed in the second mode. And it can prevent that dust adheres again in the state of the 1st, 2nd stage (dust removal modes 1 and 2) of the 2nd mode under removal.

  Further, the second filter 31 is disposed at the air inlet 211 of the fan 21 only when the second mode (dust removal mode) is started. For this reason, in the normal use state (first mode in FIG. 9), the second filter 31 can be eliminated, and the output (for example, the rotational speed) of the fan 22 can be reduced from that in the second mode, resulting in noise reduction. I can do it.

  As described above, in the present embodiment, the noise is reduced during normal cooling (first mode), and the dust of the light valve and optical components around the light valve can be removed during dust removal (second mode). The projected image apparatus can be provided.

(Modification)
As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

(Modification 1)
In the above-described embodiment, in the second mode, the second filter that removes the second size dust smaller than the first size dust is provided at the air inlet of the fan in a state where the first filter is effectively present. However, this is not a limitation. That is, in the second mode, the first filter may not be effectively present, and the second filter may be used instead of the first filter.

  In addition, the first filter is not limited to being provided in common for each RGB light in the first mode, but may be provided for each RGB light.

(Modification 2)
In the above-described embodiment, the reflection type is shown as the light valve. However, the present invention is not limited to this, and a transmission type can be used as the light valve. In the above-described embodiment, the quarter wavelength plate is shown as the optical element, but the present invention is not limited to this. That is, the present invention can be similarly applied to a projection image apparatus in which, for example, a polarizing plate is provided as an optical element in an optical path between a transmission type light valve and a prism that branches or combines optical paths.

(Modification 3)
In the embodiment described above, the air blowing system is provided for each of the RGB lights, but may be shared by any two of the RGB lights. For example, in addition to the case where a ventilation system is provided for each of the light valves 111R and 111B in FIG. 8, only one common ventilation system may be provided for the light valves 111R and 111B.

(Modification 4)
In the above-described embodiment, the first filter is provided in the intake portion of the apparatus main body, and the second filter is provided in the intake portion of the blower fan. However, the present invention is not limited to this. The first filter and the second filter may be disposed in the air path from the air inlet of the apparatus main body to at least one of the light valve, the prism, and the optical element, respectively, to be cooled.

7 .... Projection lens, 12 .... Polarizing plate, 13 .... Prism, 21 ... Blow fan, 31 ... Second filter, 50 ... First filter, 111 ... Light valve

Claims (18)

A light valve,
A prism for branching or synthesizing the optical path;
An optical element provided in an optical path between the light valve and the prism;
A projection optical system that projects a light beam from the light valve onto a projection surface;
An image projection apparatus having
A fan that blows air sucked from an air inlet of the apparatus main body toward at least one of the light valve, the prism, and the optical element to be cooled;
Operable in a first mode for cooling and a second mode for dust removal;
In the first mode, air is blown to the object to be cooled through a first filter arranged in an air passage extending from the air inlet of the apparatus main body to the object to be cooled and capable of removing dust of a first size or larger,
In the second mode, through a second filter disposed in an air passage extending from the air inlet of the apparatus main body to the object to be cooled and capable of removing dust of a second size or larger than the first size of dust. An image projection apparatus that blows air to the object to be cooled.   The image projection apparatus according to claim 1, wherein in the second mode with respect to the first mode, an amount of air blown from the blower fan is increased.   The said 1st filter is provided in the inlet port of the said apparatus main body, The said 2nd filter is provided in the inlet port of the said ventilation fan downstream from the inlet port of the said apparatus main body, The Claim 1 or 2 characterized by the above-mentioned. The image projection apparatus described. In the first mode, the blower fan has a first air path forming member that forms an air path to the light valve or the optical element at the outlet of the blower fan,
2. The first air path forming member in the second mode, and a second air path forming member that forms at least an air path to the prism at an outlet of the blower fan. 4. The image projection apparatus according to any one of items 3.   5. The image projection apparatus according to claim 4, wherein in the second mode, the first air path forming member is used as a first stage, and the second air path forming member is used as a second stage.   The image projection device according to claim 1, wherein the light valve is of a reflective type.   The image projection apparatus according to claim 6, wherein the prism is a polarization beam splitter, and the optical element is a quarter-wave plate.   The image projection apparatus according to claim 1, wherein the light valve is a transmissive type.   The image projection apparatus according to claim 8, wherein the optical element is a polarizing plate.   The image projection apparatus according to claim 1, wherein in the second mode, the second filter is provided together with the first filter.   10. The image projection apparatus according to claim 1, wherein in the second mode, the second filter is provided instead of the first filter. 11.   12. The image projection apparatus according to claim 1, further comprising means for suppressing heat generation of at least one of the light valve, the optical element, and the prism in the second mode.   The image projection apparatus according to claim 13, wherein the means for suppressing heat generation is a means for reducing the amount of light incident on the light valve.   The image projection apparatus according to claim 13, wherein the means for suppressing heat generation is power consumption suppression means for the light valve.   The image projection apparatus according to claim 1, wherein the second mode is set at least when the apparatus main body is turned off.   The image projection apparatus according to claim 1, wherein at least one of the light valve, the optical element, and the prism includes a dust adhesion detection unit.   5. The image projection apparatus according to claim 4, wherein the second air path forming member is disposed after a predetermined time after the second filter is disposed.   The image projecting apparatus according to claim 1, wherein the second filter is a filter that removes dust of 30 μm or less.