JP2016009162A - Image projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently clean optical components without affecting projection images.SOLUTION: An image projection device comprises: a wind guide (a wind guide tube 61) that guides a cleaning gas to an optical component (for example, a color wheel 23 and a light tunnel 25) as a cleaning object; a chamber 62 that is connected to the wind guide in a state communicating with the wind guide and forms a closed space allowing light to pass through an interior of the chamber; and a nozzle 67 that is provided in the chamber, and blasts the cleaning gas to an optical component of object. A part of a side wall of the chamber is composed of a translucent optical element (lens 27a).

Description

  The present invention relates to an image projection apparatus, and more particularly, to an image projection apparatus in which, when dust adheres to an optical component constituting the image projection apparatus, the attached dust can be easily removed by blowing it off with a gas.

In order not to deteriorate the quality of the image projected by the image projection apparatus, it is necessary to prevent the dust from adhering to the optical components constituting the image projection apparatus. For this reason, many of the optical components constituting the image projection apparatus are accommodated in a sealed space where dust does not enter.
On the other hand, there are optical components that cannot be placed in a sealed space in the housing. For example, a color wheel or a light tunnel. The color wheel is a component that converts white light from the light source unit into light that repeats each color of RGB every unit time while rotating at high speed. The light tunnel is a component that uniformizes the illuminance distribution of the light emitted from the color wheel and leads it to the relay lens at the next stage. In both the color wheel and the light tunnel, the adhesion of dust affects the brightness of the projected image, so it is necessary to prevent the dust from adhering to these optical components. However, the color wheel and the light tunnel are components in which heat generated by light continuously irradiated from the light source unit accumulates and needs to be cooled. For this reason, these optical components are accommodated in a non-sealed state in the housing in order to enable cooling by air.
In order to prevent dust from adhering to the color wheel and the light tunnel, it is also effective to provide a filter that traps dust at the outside air intake port located at the appropriate position of the housing. It is difficult to prevent completely.
Therefore, Patent Document 1 describes an image projection apparatus provided with an air blowing device that removes dust adhering to an optical component. This air blowing device maintains the quality of a projected image by blowing air on the surface of a projection lens as an optical component to forcibly blow off dust.

Here, in the image projection apparatus described in Patent Document 1, in order to inject air along the surface of the projection lens, a nozzle for injecting air is arranged on the side of the projection lens. For this reason, the projection lens can be efficiently cleaned while the nozzle is in a position that does not affect the projected image. However, depending on the position and shape of the optical component to be cleaned, it may be difficult to efficiently clean the optical component without affecting the projected image even if the arrangement of the nozzles is devised.
The present invention has been made in view of the above circumstances, and an object thereof is to provide an image projection apparatus capable of efficiently cleaning an optical component without affecting a projection image.

  In order to solve the above-described problems, the invention described in claim 1 includes a light source unit having a light source, an image forming unit that forms an image using light emitted from the light source, and the image forming unit. A projection unit that projects a formed image toward a projection surface; and for cleaning the target optical component as a cleaning target constituting the light source unit, the image forming unit, or the projection unit. An air guide path for guiding the gas, a chamber connected to the air guide path in communication with the air guide path, and forming a closed space through which the light passes, and the cleaning provided in the chamber And a jet outlet for jetting the gas for use to the target optical component.

  In the present invention, since light is allowed to pass through the inside of a chamber that forms a closed space with a jet outlet for jetting a cleaning gas to the target optical component, the optical component is efficiently cleaned without affecting the projected image. can do.

It is a perspective view which shows the positional relationship of the projector and projection surface which concern on one Embodiment of this invention. It is the figure which showed typically the horizontal cross section (YZ cross section) of a projector. It is an enlarged view of the chamber periphery of a cleaning unit, (a) shows the state which is not cleaning an optical component, (b) is a figure which shows the state which is cleaning the optical component with the gas for cleaning.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. . In the present invention, air or high-pressure gas is sent toward an optical component, and dust attached to the optical component is blown off by wind pressure to be removed.

[Basic projector configuration-external]
First, an embodiment of a projector as an image projection apparatus to which an embodiment of the present invention is applied will be described. FIG. 1 is a perspective view showing a positional relationship between a projector and a projection surface according to an embodiment of the present invention. In the following description, the normal direction of the projection surface S is the X direction, the short axis direction (vertical direction) of the projection surface is the Y direction, and the long axis direction (horizontal direction) of the projection surface S is the Z direction.
As shown in FIG. 1, a transmissive glass 101 that emits a projection image P is provided on the upper surface of the projector 1, and the projection image P emitted from the transmissive glass 101 is projected onto a projection surface S such as a screen. The
An operation unit 102 for the user to operate the projector 1 is provided on the upper surface of the projector 1. A focus lever 103 for adjusting the focus is provided on the side surface of the projector 1. By operating the operation unit 102 including a well-known input mechanism such as a button, it is possible to perform network settings such as color tone and contrast adjustment of the projected image P, or IP address setting.

[Internal configuration of projector-Internal]
FIG. 2 is a diagram schematically showing a horizontal section (YZ section) of the projector. The projector 1 includes a light source unit 10 including an arc tube 11 as a light source, an image forming unit 20 that forms an image using illumination light emitted from the arc tube 11, and an image formed by the image forming unit 20. Is projected toward the projection surface. The image forming unit 20 includes an image display element mechanism 33 as an image generation element that modulates light based on image data, and an illumination unit 21 that irradiates the image display element mechanism 33 with light from a light source. The projector 1 also includes a control unit 50 that controls the operation of each unit of the projector 1.
The light source unit 10 is a device that emits white light toward the illumination unit 21, and includes an arc tube 11 and a reflector 13. As the arc tube 11, for example, a halogen lamp, a xenon lamp, a metal halide lamp, an ultrahigh pressure mercury lamp, or the like can be used. The reflector 13 reflects and collects light from the arc tube 11 in order to efficiently obtain light with high illuminance.

The illumination unit 21 includes a color wheel 23, a light tunnel 25, relay lenses 27 (27a, 27b), a plane mirror 29, and a concave mirror 31.
The color wheel 23 has a disk shape, and, for example, RGB filters are arranged along the circumferential direction as a plurality of color filters having different colors. While rotating, the color wheel 23 converts white light from the light source unit 10 into light in which each color of RGB repeats every unit time, and emits the light toward the light tunnel 25. The light tunnel 25 is disposed downstream of the color wheel 23 in the light emission direction, and is configured in a cylindrical shape by laminating plate glasses. The light tunnel 25 propagates the light emitted from the color wheel 23 while reflecting the light from the inner surface of the hollow portion, thereby converting the light into a uniform light illuminance distribution (intensity distribution) and directing the light toward the relay lens 27. And inject. The illustrated relay lens 27 is configured by combining two lenses 27a and 27b, and condenses light while correcting axial chromatic aberration of light emitted from the light tunnel 25. The plane mirror 29 and the concave mirror 31 reflect the light emitted from the relay lens 27 and guide it to the image display element mechanism 33 to collect it.

The image display element mechanism 33 has a rectangular mirror surface composed of a plurality of micromirrors, and each micromirror is driven in a time-sharing manner based on video data, so that projection light is generated so as to form a predetermined video. A DMD (Digital Micro-mirror Device) element that is processed and reflected is provided.
The projection unit 40 includes a plurality of projection lenses 41 that project the image formed by the image display element mechanism 33 toward the external projection surface S as projection light L.

In the illumination unit 21, the white light emitted from the light source unit 10 is separated into RGB by the color wheel 23 and guided to the image display element mechanism 33. The image display element mechanism 33 forms an image according to the modulation signal based on the video data, and reflects the light used for the projection image to the projection unit 40 by each micromirror. The light reflected to the projection unit 40 is enlarged in the process of passing through the plurality of projection lenses 41, and enlarged and projected onto the projection surface S as the projection light L. In the image display element mechanism 33, unnecessary light that is not used in the projection image is reflected by each micromirror to an OFF light plate (not shown).
The controller 50 controls the voltage applied to the arc tube 11 so that the arc tube 11 emits light with a predetermined light amount or stops light emission. The control unit 50 controls the color wheel 23 so that the color wheel 23 rotates at a predetermined speed or stops rotating.

[Cleaning unit]
A projector according to an embodiment of the present invention will be described with reference to FIGS. The projector 1 according to the present embodiment includes a cleaning unit 60 that removes dust adhering to optical components constituting the projector 1 by air blowing. FIGS. 3A and 3B are enlarged views of the periphery of the chamber of the cleaning unit, where FIG. 3A shows a state where the optical component is not cleaned, and FIG. 3B shows a state where the optical component is cleaned with the cleaning gas. is there.
The cleaning unit 60 is connected to the air guide pipe 61 in a state where it communicates with the air guide pipe 61 (air guide path) that guides the cleaning air (cleaning gas) to the target optical component to be cleaned. And a chamber 62 that forms a closed space through which light passes, and an ejection port 67 that is provided in the chamber 62 and ejects cleaning air to the target optical component.
Here, the target optical component as a cleaning target is a component constituting the light source unit 10, the image forming unit 20, or the projection unit 40. In particular, in the present embodiment, the light tunnel 25 and the color wheel 23 constituting the illumination unit 21 of the image forming unit 20 are to be cleaned.

The air guide tube 61 is in the form of a hollow pipe, and is arranged avoiding the optical path. A chamber 62 is disposed at one end 61a of the air guide tube 61, and a connection port 63 to which a generation source of cleaning air is connected is provided at the other end 61b. The connection port 63 is an opening provided at an end portion of the air guide tube 61 and is disposed at an appropriate position on the housing side surface 1 a of the projector 1.
In addition, you may provide the cover member which closes the connection port 63. FIG. When the light tunnel 25 and the color wheel 23 are not cleaned, the connection port 63 can be closed with a lid member to prevent dust from entering the air guide tube 61.
The generation source of the cleaning air is, for example, an aerosol spray such as an air duster, or a compressor (not shown) that compresses and injects air. In the illustrated example, the nozzle 111 of the air duster 110 is inserted into the air guide tube 61. Compressed air is fed into the air guide pipe 61 as cleaning air. A gas other than air may be used for cleaning the optical component.

The chamber 62 has a hollow shape including an inlet 65 into which the cleaning gas flows and an outlet 67 through which the cleaning gas is jetted. One end portion 61a of the air guide tube 61 is inserted into the inflow port 65, and the chamber 62 and the air guide tube 61 are connected so that their internal spaces communicate with each other. Further, the downstream end of the light tunnel 25 in the light emission direction is connected to the ejection port 67, and the internal space of the chamber 62 and the light tunnel 25 communicates with each other.
The chamber 62 is hermetically sealed except for the inlet 65 and the jet 67 and forms a sealed space. That is, the cleaning air that has flowed into the chamber 62 from the inflow port 65 is jetted out of the chamber 62 only from the jet port 67.
The chamber 62 is disposed on the optical path, and the light emitted from the light tunnel 25 enters the chamber 62 via the ejection port 67. At least a part of the side wall of the chamber 62, specifically, the side wall portion on the downstream side in the traveling direction of the light beam of the chamber 62 is translucent. In the present embodiment, the lens 27 a that is a light-transmitting optical element disposed on the optical path constitutes the light-transmitting side wall portion of the chamber 62. The light that has entered the chamber 62 passes through the lens 27a and enters the lens 27b on the downstream side in the light beam traveling direction.

The pressure in the chamber 62 rises when cleaning air is sent from the air duster 110. As the internal pressure in the chamber 62 increases, cleaning air is ejected from the ejection port 67. The cleaning air ejected from the ejection port 67 enters the light tunnel 25 from the downstream side in the light beam traveling direction toward the upstream side, and cleans the inside of the light tunnel 25. Further, since the cleaning air that has passed through the light tunnel 25 is blown to the color wheel 23, the color wheel 23 can be cleaned simultaneously with the light tunnel 25.
According to the present embodiment, light is allowed to pass through the inside of the chamber 62 that includes the ejection port 67 that ejects the cleaning gas to the optical components (the light tunnel 25 and the color wheel 23) to be cleaned and forms a closed space. Therefore, the optical component can be efficiently cleaned without affecting the projected image.
In addition, since at least a part of the side wall of the chamber 62 is composed of the lens 27a that is a light-transmitting optical element, the degree of freedom in arranging the chamber 62 is increased.

<Connection detection sensor>
A connection detection sensor 91 (connection detection means) for detecting that a generation source of cleaning air is connected to the wind guide pipe 61 is disposed at an appropriate position (near the connection port 63) of the other end portion 61b of the wind guide pipe 61. Has been. For example, the connection detection sensor 91 normally protrudes into the air guide pipe 61 and is pushed by the nozzle 111 when the nozzle 111 or the like of the air duster 110 is inserted into the air guide pipe 61 and retracts from the air guide pipe 61. It is possible to use a detection piece 93 that performs detection and a transmission type photosensor that detects the position (or posture) of the detection piece 93.

The control unit 50 controls the light source unit 10 based on the detection signal (detection result) from the connection detection sensor 91 when the connection detection sensor 91 detects the connection of the air duster 110 to the air duct 61. Functions as a means. Specifically, when the connection detection sensor 91 detects that the air duster 110 is connected to the air guide tube 61, the control unit 50 causes the light emitting tube 11 to reduce the amount of emitted light or stop light emission. The voltage applied to the arc tube 11 is controlled. Thus, when performing dust removal by air blow, it is possible to prevent unnecessary images from being projected onto the projection surface S by reducing the amount of emitted light or stopping light emission.
Further, the control unit 50 serves as drive control means for driving and controlling the color wheel 23 based on a detection signal from the connection detection sensor 91 when the connection detection sensor 91 detects the connection of the air duster 110 to the wind guide pipe 61. Function. Specifically, when the connection detection sensor 91 detects that the air duster 110 is connected to the air guide pipe 61, the control unit 50 causes the color wheel 23 to rotate at a predetermined rotational speed. 23 is rotated. By rotating the color wheel 23 in this way, the dust D ejected from the light tunnel 25 can be prevented from adhering to the color wheel 23. Further, the surface of the color wheel 23 can be uniformly cleaned by the cleaning air blown to the color wheel 23 through the light tunnel 25.

<Blower detection sensor>
The projector 1 includes an air blowing detection sensor 95 (air blowing detecting means) that detects that cleaning air has been sent into the air guide tube 61 and / or the chamber 62.
As the air blowing detection sensor 95, an air detection piece 97 that is swingably disposed at an appropriate position in the air duct 61 or the chamber 62 and a transmission type photosensor that detects the position (or posture) of the air detection piece 97 are used. Can do. The air detection piece 97 takes an initial posture (solid line in FIG. 2) that protrudes on the cleaning air path when the cleaning air does not flow into the air duct 61 and / or the chamber 62. When it flows in, it is supported so as to be able to swing so as to take a retracted posture (dotted line in FIG. 2) along the traveling direction of the cleaning air by the wind pressure of the cleaning air.
In addition, when a blower such as a compressor is used as a generation source of cleaning air, a means for detecting on / off of a blower switch for starting or stopping the blower of the blower is provided in the control unit 50, and this is detected. It may be used as a means.

  When the blower detection sensor 95 detects that the cleaning air has been sent into the air guide pipe 61 and / or the chamber 62, the control unit 50 is based on a detection signal (detection result) from the blower detection sensor 95. It functions as a light source control means for controlling the light source unit 10. Specifically, when the air blowing detection sensor 95 detects that the cleaning air has been sent into the air guide tube 61 and / or the chamber 62, the control unit 50 reduces the light emission amount by the light emitting tube 11 or The voltage applied to the arc tube 11 is controlled so as to stop the light emission. Thus, when performing dust removal by air blow, it is possible to prevent unnecessary images from being projected onto the projection surface S by reducing the amount of emitted light or stopping light emission.

Furthermore, when the air blow detection sensor 95 detects that the cleaning air has been sent into the air guide pipe 61 and / or the chamber 62, the control unit 50 is based on the detection signal from the air blow detection sensor 95. It functions as a drive control means for controlling the drive. Specifically, when the air blowing detection sensor 95 detects that cleaning air has been sent into the air guide pipe 61 and / or the chamber 62, the control unit 50 rotates the color wheel 23 at a predetermined rotational speed. Thus, the color wheel 23 is driven to rotate. By rotating the color wheel 23 in this way, the dust D ejected from the light tunnel 25 can be prevented from adhering to the color wheel 23. Further, the surface of the color wheel 23 can be uniformly cleaned by the cleaning air blown to the color wheel 23 through the light tunnel 25.
The control is performed when the connection detection sensor 91 or the air blowing detection sensor 95 detects that the air duster 110 is connected or that cleaning air is fed into the air guide pipe 61 and / or the chamber 62. You may make it perform at least one of control of the light source unit 10 by the part 50, and control of the color wheel 23. FIG.

[Example Embodiments and Effects]
The present invention can be implemented in the following modes.
<First embodiment>
A light source unit 10 having a light source (light emitting tube 11), an image forming unit that forms an image using light emitted from the light source, and a projection that projects an image formed by the image forming unit toward the projection surface S In the image projection apparatus (projector 1) including the unit 40, cleaning is performed on a target optical component (for example, the color wheel 23 and the light tunnel 25) as a cleaning target constituting the light source unit, the image forming unit, or the projection unit. An air guide path (air guide pipe 61) for guiding gas (cleaning air), a chamber 62 connected to the air guide path in a state of communicating with the air guide path, and forming a closed space through which light passes; And an ejection port 67 provided in the chamber for ejecting a cleaning gas to the target optical component.
Since the light is allowed to pass through the inside of the chamber that forms the closed space by providing the ejection port for ejecting the cleaning gas to the target optical component, the optical component can be efficiently cleaned without affecting the projected image.

<Second embodiment>
At least a part of the side wall of the chamber 62 is composed of a light-transmitting optical element (lens 27a).
Since at least a part of the side wall of the chamber 62 is composed of a light-transmitting optical element, the degree of freedom in arranging the chamber is increased.

<Third embodiment>
Connection detection means (connection detection) that is disposed at an appropriate position on the other end portion 61b of the air guide path (air guide pipe 61) and detects that a cleaning gas source (air duster 110 or the like) is connected to the air guide path. Sensor 91) and light source control means (control unit 50) for controlling the operation of the light source (arc tube 11) based on the detection result (detection signal) of the connection detection means, and the generation source of the cleaning gas is introduced. When the connection detecting means detects that the air passage is connected, the light source control means controls the light source to reduce the amount of emitted light or to stop emitting light.
When performing dust removal by air blow, it is possible to prevent unnecessary images from being projected onto the projection surface S by reducing the amount of emitted light or stopping light emission.

<Fourth embodiment>
The optical component to be cleaned is a rotatable color wheel 23 that constitutes the image forming unit 20 and has a plurality of different color filters arranged in the circumferential direction. ) And a connection detection means (connection detection sensor 91) for detecting that a cleaning gas generation source (air duster 110 or the like) is connected to the air duct, and a connection detection means. Drive control means (control unit 50) for controlling the operation of the color wheel based on the detection result (detection signal), and the connection detection means that the generation source of the cleaning gas is connected to the air duct. When detected, the drive control means rotates the color wheel.
The surface of the color wheel 23 can be cleaned by blowing cleaning air onto the color wheel 23. Moreover, the surface of the color wheel 23 can be uniformly cleaned by rotating the color wheel 23 at the time of cleaning.

<Fifth embodiment>
Blower detection means (blower detection sensor 95) for detecting that the cleaning gas has been sent into the wind guide path (wind guide pipe 61), and a light source (luminous tube) based on the detection result (detection signal) of the blower detection means. 11) and a light source control means (control section 50) for controlling the operation of the light source control means when the air blowing detection means detects that the cleaning gas has been sent into the air guide passage. Control is performed such that the amount of emitted light is reduced or the emission is stopped.
When performing dust removal by air blow, it is possible to prevent unnecessary images from being projected onto the projection surface S by reducing the amount of emitted light or stopping light emission.

<Sixth embodiment>
The optical component to be cleaned is a rotatable color wheel 23 that constitutes the image forming unit 20 and has a plurality of different color filters arranged in the circumferential direction. ) A blowing detection means (blowing detection sensor 95) for detecting that the cleaning gas has been fed into, and a drive control means (control) for controlling the operation of the color wheel based on the detection result (detection signal) of the blowing detection means. Part 50), and when the air blowing detecting means detects that the cleaning gas is sent into the air guide passage, the drive control means rotates the color wheel.
The surface of the color wheel 23 can be cleaned by blowing cleaning air onto the color wheel 23. Moreover, the surface of the color wheel 23 can be uniformly cleaned by rotating the color wheel 23 at the time of cleaning.

<Seventh embodiment>
The image forming unit 20 includes a cylindrical light tunnel 25 that makes the illuminance distribution of the light emitted from the color wheel uniform on the downstream side of the light emission direction from the color wheel 23. It is connected to the downstream side of the light beam emission direction of the tunnel, and the ejection port is characterized by injecting a cleaning gas (cleaning air) into the light tunnel from the downstream side in the light emission direction toward the upstream side.
The inside of the light tunnel 25 can be cleaned by the cleaning air jetted from the jet outlet 67. Further, since the cleaning air that has passed through the light tunnel 25 is blown to the color wheel 23, the color wheel 23 can be cleaned simultaneously with the light tunnel 25.

  DESCRIPTION OF SYMBOLS 1 ... Projector (image projection apparatus), 1a ... Housing side surface, 10 ... Light source unit, 11 ... Light emission tube (light source), 13 ... Reflector, 20 ... Image forming unit, 21 ... Illumination unit, 23 ... Color wheel, 25 ... Light tunnel, 27 ... relay lens, 27a, 27b ... lens, 29 ... plane mirror, 31 ... concave mirror, 33 ... image display element mechanism, 40 ... projection unit, 41 ... projection lens, 50 ... control unit (light source control means, Drive control means), 60 ... cleaning unit, 61 ... air guide pipe (air guide path), 61a ... one end, 61b ... other end, 62 ... chamber, 63 ... connection port, 65 ... inlet, 67 ... jet port 91 ... Connection detection sensor (connection detection means), 93 ... Detection piece, 95 ... Air blow detection sensor (fan detection means), 97 ... Air detection piece, 101 ... Transmission glass, 102 ... Operation part, 1 3 ... focus lever, 110 ... air duster (source of cleaning gas), 111 ... nozzle, S ... projection surface, P ... projected image

JP 2006-220835 A

Claims (7)

A light source unit having a light source, an image forming unit that forms an image using light emitted from the light source, and a projection unit that projects an image formed by the image forming unit toward a projection surface. In the image projection device
An air guide path that guides a cleaning gas to a target optical component that constitutes a cleaning target constituting the light source unit, the image forming unit, or the projection unit, and is connected to the air guide path in communication with the air guide path And a chamber forming a closed space through which the light passes, and a jet port provided in the chamber for ejecting the cleaning gas to the target optical component. Projection device.   The image projection apparatus according to claim 1, wherein at least a part of the side wall of the chamber is made of a translucent optical element. Based on the detection result of the connection detection means, the connection detection means that is disposed at a suitable position on the other end side of the air guide path and detects that the generation source of the cleaning gas is connected to the air guide path. A light source control means for controlling the operation of the light source,
When the connection detection unit detects that the generation source of the cleaning gas is connected to the air guide path, the light source control unit controls the light source to reduce the amount of emitted light or stop light emission. The image projection apparatus according to claim 1, wherein: The target optical component is a rotatable color wheel that constitutes the image forming unit and in which a plurality of color filters having different colors are arranged along the circumferential direction.
Based on the detection result of the connection detection means, the connection detection means that is disposed at a suitable position on the other end side of the air guide path and detects that the generation source of the cleaning gas is connected to the air guide path. Drive control means for controlling the operation of the color wheel,
4. The drive control means rotates the color wheel when the connection detecting means detects that the cleaning gas generation source is connected to the air guide passage. The image projection device according to any one of the above. Blower detection means for detecting that cleaning gas has been sent into the air guide path, and light source control means for controlling the operation of the light source based on the detection result of the blower detection means,
When the air blowing detection unit detects that the cleaning gas has been sent into the air guide passage, the light source control unit controls the light source to reduce the amount of emitted light or stop emitting light. The image projection apparatus according to claim 1 or 2, characterized in that The target optical component is a rotatable color wheel that constitutes the image forming unit and in which a plurality of color filters having different colors are arranged along the circumferential direction.
An air blowing detecting means for detecting that the cleaning gas has been sent into the air duct, and a drive control means for controlling the operation of the color wheel based on the detection result of the air blowing detecting means,
6. The drive control means causes the color wheel to rotate when the air blowing detection means detects that a cleaning gas has been sent into the air guide passage. The image projection apparatus described. The image forming unit includes a cylindrical light tunnel that makes the illuminance distribution of the light emitted from the color wheel uniform on the downstream side in the light emission direction from the color wheel,
The ejection port of the chamber is connected to the downstream side in the light emission direction of the light tunnel, and the ejection port ejects cleaning gas into the light tunnel from the downstream side in the light emission direction to the upstream side. The image projection apparatus according to claim 4, wherein the image projection apparatus is an image projection apparatus.

Images