JP2008083583A - Screen for projector, and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cope with dynamic image blur on the screen side, when displaying a dynamic image from a projector onto the screen. <P>SOLUTION: In the reflection type screen 100, a screen belt 110 is extended around a first roller 101 and a second roller 102 disposed parallel to each other, and a screen section SK is formed in between the first roller 101 and second roller 102. The screen belt 110 is a white endless belt so as to have the function of reflecting the light that has reached a belt surface (projection light of the projector 10). The screen belt has band-like sections 112 extending in the direction of the belt width, and remainder sections 114, excluding the band-like sections 112. The band-like sections 112 have a black color or a color close to it and have the function of absorbing light that has reached the belt surface. Accordingly, for the reflection-type screen 100, the band-like sections 112, where dynamic images are not displayed even if projected light reaches there, are made to move within the screen area SK. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a projector that projects a moving image obtained by scanning and outputting a video signal, and displays a moving image by transmitting or reflecting the projection light emitted when the projector projects a moving image. The present invention relates to a projector screen.

  Since the screen displays a moving image obtained by scanning and outputting a video signal by a projector, various proposals have been made to improve the quality of the display image (for example, Patent Document 1).

  Although the screen proposed in the above-mentioned patent document prevents the reflection of room illumination light by making its reflectance variable, it improves the quality of the displayed image. However, it is unique to displaying moving images. It does not contribute to the suppression or elimination of video blur. When displaying a moving image, the image generally changes every frame, and the viewer recognizes the moving image by continuing to watch the image change. When such image transition for each frame is viewed, an afterimage of the image remains on the human retina, so that the next image overlaps the afterimage and the moving image becomes blurred, resulting in motion blur. Since the deterioration in quality due to the moving image blur is completely different from the deterioration in quality due to the reflection of the indoor illumination light, as described above, the screen proposed in Patent Document 1 aims to suppress or eliminate the moving image blur. You can't.

  On the other hand, a technique for achieving suppression or elimination of moving image blur on the side of a device that generates a moving image has also been proposed (for example, Patent Document 2). This patent document instantly displays a black image based on a signal of a fixed level (e.g., black level) during image transition for each frame to prevent afterimages and use this to suppress or eliminate motion blur. ing. Although the above patent document is applied to a liquid crystal display device, the same applies to a projector in that a moving image is obtained. Therefore, by applying the technique of this patent document in the generation of a moving image in a projector. Therefore, it is expected to be effective in suppressing and eliminating moving image blur in a moving image displayed by projecting light from a projector onto a screen.

JP 2003-121943 A JP 2006-106689 A

  However, in order to cope with such moving image blurring on the existing projector side, it is necessary to match with other control devices and circuit configurations that the projector has for image generation. I need. If it is a new product, it will be necessary to change the design and manufacturing equipment in consideration of moving image blur.

  The present invention has been made to solve the above problems, and an object thereof is to provide a new method for dealing with moving image blur when displaying a moving image of a projector on a screen. Its purpose is to provide a possible new screen.

  In order to solve at least a part of such problems, the projector screen of the present invention is used together with a projector that projects a moving image obtained by scanning and outputting a video signal, and when the projector projects the moving image. A screen area for displaying the moving image is formed by a screen belt made of an endless belt when the projected light to be emitted arrives. This screen belt is looped over each roller of a roller group including at least a pair of rollers in which long rollers are arranged in parallel to form a loop locus, and a screen region is formed in the loop locus between the roller pairs. To do. The screen belt is wound from the upper end side to the lower end side of the screen region along the loop trajectory by roller drive control means for driving and controlling the rollers of the roller group.

  The screen belt wound up in this way has a band-like area formed in a band shape in the width direction of the endless belt, and a remaining area excluding the band-like area, and the projected light that has reached the band-like area is a moving image. The remaining area is made to have the property of reaching the projected light reaching the viewer side. For this reason, as described above, when the screen belt is wound along the loop trajectory, the belt-like region moves from the upper end side to the lower end side in the screen region, and the belt-like region that moves with the above properties. Prevents the viewer from seeing the moving image in the screen area. On the other hand, the remaining area other than the moving belt-like area receives the projected light that has arrived, displays a moving image, and allows the viewer to visually recognize the moving image.

  Therefore, in the projector screen of the present invention, during the image projection for each frame as described above, the image is changed while changing the image portion of a part of the frame image while allowing the viewer to visually recognize all the frame images. Do not let the viewer see the part. Therefore, according to the projector screen of the present invention, the afterimage of the retina can be suppressed independently on the screen side so that the viewer who is viewing the image does not see the image. As a result, according to the projector screen of the present invention, it is possible to provide a new screen capable of dealing with moving image blurring when a moving image of the projector is projected and displayed on the screen. That is, when improving the moving image display quality by suppressing or eliminating the moving image blur, it is not necessary to modify the existing projector or change the circuit, so that the moving image display quality can be easily improved. Further, since the screen belt only needs to be driven (taken up) along the loop trajectory, the versatility is improved because it does not depend on the method of moving image generation and projection light irradiation on the projector side.

  In this case, when the screen belt is driven (taken up) along the loop trajectory, the projector receives the scanning status signal indicating the scanning output status of the video signal from the projector, or receives the video signal input to the projector. A scanning status signal representing the status of scanning output is generated from the equally distributed video signal, and the rollers of the roller group are driven and controlled based on the scanning status signal, and the belt-like area is synchronized with the scanning output of the video signal. And can be moved in the screen area. By doing so, the effectiveness of suppressing the afterimage of the retina by preventing the image from being displayed during the image transition for each frame is enhanced, which is preferable for improving the moving image display quality.

  Then, in the remaining area of the screen belt, the projection light is brought to the viewer side by exhibiting the function of light transmission or light reflection, and light is transmitted in the belt-like area of the screen belt. By exhibiting the absorbing function, the projection light can be prevented from reaching the viewer. In this way, the moving image is displayed in the range corresponding to the remaining area in the screen area by the function of light transmission or light reflection exhibited by the remaining area of the screen belt. On the other hand, due to the light absorption function exhibited by the band of the screen belt, in the screen area, the moving image is not displayed within the range corresponding to the band, and the range where the moving image is not displayed is moved. .

  The projector screen of the present invention described above can take various forms. For example, the projector includes a reflection mirror that reflects projection light emitted when the projector projects the moving image, and the screen area formed by the screen belt between the roller pair is defined as the reflection mirror. The reflected light reflected from the projector is opposed to the reflecting mirror so that the loop trajectory up to the pair of rollers passes through the back of the reflecting mirror and does not block the projection light from the projector. To. Then, the remaining area of the screen belt can exhibit a light transmission function to bring the projection light to the viewer side. In this way, the optical path can be bent while ensuring the optical path length of the projection light from the projector to the screen belt, so that the screen belt and the projector can be arranged close to each other, and the space can be saved.

  In this case, the reflection mirror is arranged on the rear side of the casing, the roller pair of the roller group is arranged on the front side of the casing, and the screen region is formed on the front side of the casing. The screen belt in a range to be covered can be made to face the reflection mirror on the front side of the housing. In this way, since the optical path of the projection light from the projector to the screen belt is surrounded by the casing, it is possible to prevent illumination light or the like from entering the optical path of the projection light, which is preferable in terms of ensuring the luminance. In addition, since the positional relationship between the reflection mirror and the screen belt on the front side of the casing is also fixed by the casing, focusing and the like are simplified and handling is also simplified.

  Moreover, it can also be set as the screen belt provided with a strip | belt-shaped area | region in multiple places at equal intervals in the said loop locus | trajectory. In this way, if the screen belt is driven at a constant speed, the belt-like area can be moved in the screen area every predetermined period (for example, a frame image display period). Moreover, even if the driving speed (winding speed) of the screen belt is reduced by the amount of the belt-like areas provided at a plurality of locations, the belt-like areas in the screen area can be moved every predetermined period (for example, the frame image display period). Since this can be ensured, the load on the roller drive source can be reduced and the sound can be silenced.

  In addition, the present invention can also be applied as a projector integrated with a screen and a casing. As a form of the projector, a reflecting mirror is arranged on the back side of the casing containing the projector, and a screen is arranged on the front side. There is a so-called rear projector.

  Hereinafter, embodiments of the present invention will be described in the following order while separating the examples according to the properties of the screen.

A: A reflective screen embodiment;
B: Transmission screen mode;

A: A reflective screen embodiment;
FIG. 1 is an explanatory view showing a reflective screen 100 as an embodiment of the present invention and a projector 10 that projects on the screen, and FIG. 2 shows a use state in which a moving image is projected on the reflective screen 100. FIG. 3 is an explanatory diagram showing a state in which the scanning output of the video signal of the projector 10 and the state of the reflective screen 100 are associated with each other.

  As shown in FIG. 1, the projector 10 and the reflective screen 100 are disposed to face each other. The projector 10 is configured to project a moving image obtained by scanning and outputting a video signal, and emits projection light toward the reflective screen 100 when projecting a moving image. The reflective screen 100 displays a moving image with the projected light that has arrived, and reflects the projected light of the displayed moving image toward a viewer who looks at the reflective screen 100 from the projector 10 side, thereby displaying the displayed moving image. Make the image visible to the viewer.

  As shown in the figure, the reflective screen 100 includes a long first roller 101 and a second roller 102 arranged in parallel, and these two rollers form a roller pair. The reflective screen 100 spans an endless belt-like screen belt 110 around the roller pair to form a loop trajectory. In this case, the screen belt 110 stretched between the rollers of the roller pair is tensioned by the tension roller 103 so that the screen belt 110 is substantially vertical between the first roller 101 and the second roller 102. The screen area SK for displaying a moving image is defined between the two rollers (between the roller pair). The position of the projector 10 with respect to the reflective screen 100 is adjusted so that projection light is applied to the screen area SK.

  In addition, the reflective screen 100 includes a motor 104 that is a power source of the second roller 102 that is a driving roller, and a control device 106 that drives and controls the motor. In this case, the motor 104 is configured as a pulse motor or a synchronous motor, rotates in response to a control signal from the control device 106, and rotates the second roller 102 in the direction indicated by the arrow in the drawing. By such rotational driving of the second roller 102, the screen belt 110 is wound from the upper end side to the lower end side of the screen region SK along the loop trajectory, as indicated by the downward arrow in the figure.

  The screen belt 110 has tensile strength and wear resistance, and also functions to reflect light (projected light from the projector 10) that has reached the belt surface, specifically, the belt surface on the projector 10 side. Since the screen belt 110 forms the screen region SK as described above, the screen belt 110 is a white endless belt. In order to exhibit the above-described properties, the screen belt 110 is formed by blending a white agent with a synthetic resin such as polyester, polyether, polyethylene, polypropylene, polyamide, urethane, fluororesin, or polyacetal. Alternatively, a glass cloth or aramid cloth having excellent mechanical properties (tensile strength) can be used as a core material, and the surface can be coated with a fluororesin.

  The screen belt 110 includes a belt-like region 112 formed in a belt shape in the width direction of the endless belt, and a remaining region 114 excluding the belt-like region 112. In the present embodiment, two strip regions 112 are formed at equal intervals on the loop trajectory of the screen belt 110. The belt-like region 112 is also a colored region colored with black or a color similar thereto, and exhibits a function of absorbing light that has reached the belt surface (projection light of the projector 10). On the other hand, the remaining area 114 may be white as described above, and exhibits the function of reflecting the light (projected light of the projector 10) reaching the belt surface. In this case, the remaining area 114 also causes scattering of light (reflected light) on the surface on the side of the projector 10 in order to display a moving image by the reflection function and allow the viewer to visually recognize the image. Is formed (displayed) on the surface of the remaining area 114. Due to the above-described properties of the band-shaped area 112 and the remaining area 114 with respect to the light, the screen belt 110 displays a moving image by the projection light of the projector 10 in the area (light reflecting area) occupied by the remaining area 114 in the screen area SK. The moving image is not displayed in the area occupied by the belt-like area 112 (light absorption area).

  For this reason, the reflection type screen 100 has a light absorption area occupied by the belt-like area 112 by winding the screen belt 110 through the rotational drive of the second roller 102, as shown in FIG. Move toward the bottom side. The light absorption area that moves in this way is an area that does not display a moving image as described above, and a moving image is displayed in the remaining area while the area that does not display a moving image moves up and down. . That is, the screen area, which is a moving image display area, becomes a light absorption area in the entire screen area while being scanned along with the movement of the light absorption area.

  Next, the relationship with the projector 10 will be described. The control device 106 included in the reflective screen 100 is connected to the projector 10. The vertical start signal when the projector 10 performs scanning output of the video signal is input from the projector 10, and the motor 104 synchronized with this signal is input. Rotation control, that is, winding control of the screen belt 110 is performed. The projector 10 scans and outputs a video signal to be projected on the reflective screen 100 by an image display device (for example, a liquid crystal panel or the like) (not shown) included in the projector itself to generate a frame unit. Then, light from a light source is applied to the image display device, and a moving image of the image display device is projected onto the reflective screen 100 by projection light in units of frames. Since the projector 10 generates and outputs a vertical start signal that matches the image generation timing in units of frames in parallel with the above-described moving image generation, by winding the screen belt 110 in synchronization with this vertical start signal, As shown in FIG. 3, the belt-like area 112 moves in synchronization with the vertical start signal in the screen area SK. The control device 106 receives an input from the sensor 130 that detects the rotation speed of the second roller 102, grasps the actual rotation state of the second roller 102, and moves the belt-shaped area 112 up and down in synchronization with the vertical start signal. Has been moved to.

  In this case, the scanning output of the video signal synchronized with the vertical start signal and the vertical clock signal in the projector 10 and the generation of the projected moving image in units of frames by this are the movement of the band-like area 112 in the reflective screen 100 described above. Is going separately. However, the reflective screen 100 performs the motor control in synchronization with the vertical start signal described above, and further the winding control of the screen belt 110, so that the movement of the band 112 matches the projection of the moving image in units of frames. To do. Specifically, assuming that a frame image is generated by scanning output of m columns of video signals in the projector 10, the projector 10 scans and outputs the m columns of video signals sequentially from the first column to the mth column. During the generation of the frame image and the projection onto the reflective screen 100, in the reflective screen 100, the belt-like area 112 moves from the upper stage to the lower stage of the screen area SK. Accordingly, during the projection of the frame image onto the reflective screen 100, the light absorption area occupied by the band area 112 is moved while the image is not displayed in the band area 112, and the remaining area 114 is displayed in the screen area SK. An image is displayed in the remaining light reflection area. The image display (frame image display) in this light reflection area is a display other than the image area that is not displayed by the moving light absorption area, but the light reflection area moves as described above, so that the frame image The entire area is displayed and is visually recognized by the viewer.

  As described above, in the reflective screen 100 of the present embodiment, all the frame images are displayed to the viewer during the image projection for each frame as described above of the projector 10 onto the reflective screen 100. While viewing, the position occupied by a part of the frame image in the frame image is changed by moving the belt-like area 112 (light absorption area) so that the viewer does not visually recognize the image part. For this reason, according to the reflective screen 100 of the present embodiment, it is possible to suppress the afterimage of the retina so that the viewer who is viewing the image does not visually recognize the image, This can be achieved independently on the reflective screen 100 side separately from the scanning output and the screen projection by the projection light of the moving image obtained thereby. As a result, the reflective screen 100 according to the present embodiment is a new screen capable of dealing with moving image blur when a moving image of the projector 10 is projected onto the reflective screen 100 and displayed. In other words, when moving picture display quality is improved by suppressing or eliminating moving picture blurring, it is possible to eliminate the need for remodeling of existing projectors and circuit changes, so that it is possible to easily improve the moving picture display quality even if such existing projectors are used. . Further, since the vertical movement of the belt-like region 112 (winding of the screen belt 110) with respect to the projection light of the projector may be performed on the reflective screen 100 side, moving image generation and projection light irradiation on the projector side are performed. Since it does not depend on this method, versatility increases.

  In addition, in this embodiment, when driving (winding) the screen belt 110 along the loop trajectory, the vertical synchronization signal from the projector 10 is received, and the rotation control of the motor 104 is performed based on this signal. The light absorption area occupied by the belt-like area 112 is moved in the screen area SK of the reflective screen 100 in synchronization with the scanning output of the video signal. Therefore, since the effectiveness of suppressing the afterimage of the retina by preventing the image from being displayed during the image transition for each frame is enhanced, it is preferable for improving the moving image display quality.

  In addition, since the screen belt 110 of the present embodiment is provided with the belt-like regions 112 at two locations at equal intervals in the loop trajectory, if the screen belt 110 is driven at a constant speed, the belt-like regions 112 are screened every frame image display period. The region SK can be moved reliably. In addition, even if the driving speed (winding speed) of the screen belt 110 is reduced by the amount of the two belt-like regions 112, the belt-like regions 112 in the screen region SK every predetermined period (for example, a frame image display period). Therefore, the load on the motor 104 can be reduced and the sound can be silenced.

B: Transmission screen mode;
Next, a description will be given of what displays a moving image from a projector on a transmissive screen and allows a viewer to visually recognize the moving image. FIG. 4 is an explanatory diagram showing the transmissive screen 200 and the projector 10 projected onto the screen. FIG. 5 is an explanatory diagram showing a schematic configuration of a rear projector 300 in which the transmissive screen 200 and the projector 10 are built in a casing. FIG.

  The transmissive screen 200 shown in FIG. 4 forms a loop locus of the screen belt 202 so as to surround the projector 10. In other words, the transmission type screen 200 has the first roller 101 and the second roller 102 disposed in front of the projector 10, and includes auxiliary rollers 107 and 108 behind the projector 10, and the screen belt 202 is stretched around these rollers. . Like the screen belt 110 described above, the screen belt 202 is provided with the belt-like regions 112 that exhibit the light absorption function at equal intervals in the loop locus, but the remaining region 114 between the belt-like regions 112 and 112 is as follows. It is transparent so as to exhibit a light transmission function. 4 makes the screen area SK between the first roller 101 and the second roller 102 face the projector 10, and the projection light from the projector 10 is transmitted between the projector 10 and the screen 10. By allowing the viewer to see the moving image, the viewer sees the moving image. Since the viewer views the image formed on the surface of the transmissive screen 200 (specifically, the light transmission surface), the transmission screen 200 scatters light on the transmission surface side, and the projection light A moving image is formed (displayed).

  The rear projector 300 shown in FIG. 5 uses the transmission screen 200 described above, but is different in arrangement with respect to the projector 10. That is, in the rear projector 300, the reflection mirror 210 that reflects the projection light from the projector 10 is disposed on the inclined back surface 315 side of the housing 310, and the first roller 101 and the first roller 101 are disposed on the front surface side of the housing 310. Two rollers 102 are arranged, and auxiliary rollers 107 to 109 are arranged on the rear side of the casing. By passing the screen belt 202 around these rollers, the screen belt 202 forms a screen region SK on the front surface side of the housing 310, and the screen region is opposed to the reflection mirror 210 on the front surface side of the housing 310. . In this case, the loop trajectory of the screen belt 202 is a trajectory that passes under the projector 10 and the back surface of the reflection mirror 210, and is a trajectory that does not block the optical path of the projection light from the projector 10 to the reflection mirror 210.

  In the rear projector 300 shown in FIG. 5, the projection light from the projector 10 is totally reflected by the reflection mirror 210, and then the reflected light reaches the screen belt 202 in front of the screen to form a screen formed by the belt. The moving image is displayed in the region SK, and the moving image is viewed by the viewer by transmitting light (reflected light) to the viewer side in front of the screen. Even in this case, the screen belt 202 forms (displays) a moving image of the projection light by scattering on the transmission surface side.

  Even in the transmissive screen 200 and the rear projector 300 having the above-described transmissive screen mode, as in the case of the screen belt 110 described above, the transmissive screen 200 and the rear projector 300 are changed in that the band-like area 112 that is a light absorption area moves in the screen area SK. is not.

  Accordingly, the transmissive screen 200 and the rear projector 300 having the transmissive screen 200 are arranged on the side of the transmissive screen 200 by matching the movement of the light absorption area with the projection of the moving image in units of frames in the same manner as the reflective screen 100 described above. To do. For this reason, the transmission screen 200 can also provide the effects described above.

  As mentioned above, although the Example of this invention was described, this invention is not restricted to above-described embodiment, In the range which does not deviate from the summary, it is possible to implement in various aspects. For example, the vertical start signal is input from the projector 10 in order to synchronize the movement of the belt-like area 112 that is the light absorption area with the scanning output of the video signal in the projector 10, but the following can also be performed. In other words, when a moving image is projected, a distributor (distribution circuit) that equally distributes a video signal input to the projector 10 is provided in the reflective screen 100 or the transmissive screen 200, and scanning is performed from the video signal obtained by the distribution. A scanning status signal representing the output status, that is, the above-described vertical synchronization signal is generated, and on the basis of this signal, point driving control of the motor 104, that is, winding control of the screen belt 110 and the screen belt 202 can be performed.

It is explanatory drawing which shows together and shows the reflection type screen 100 as one Example of this invention, and the projector 10 projected on this screen. It is explanatory drawing which shows the mode of the use condition which is projecting the moving image on the reflective screen. FIG. 4 is an explanatory diagram showing a scan output of a video signal of the projector 10 and a state of the reflective screen 100 in association with each other. It is explanatory drawing which shows together and shows the transmissive screen 200 and the projector 10 projected on this screen. It is explanatory drawing which shows schematic structure of the rear projector 300 which incorporated the transmissive screen 200 and the projector 10 in the housing | casing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Projector 100 ... Reflective type screen 101 ... 1st roller 102 ... 2nd roller 103 ... Tension roller 104 ... Motor 106 ... Control apparatus 107-109 ... Auxiliary roller 110 ... Screen belt 112 ... Belt-like area 114 ... Residual area 130 ... Sensor DESCRIPTION OF SYMBOLS 200 ... Transmission type screen 202 ... Screen belt 210 ... Reflection mirror 300 ... Rear projector 310 ... Housing | casing 315 ... Back SK ... Screen area

Claims (9)

In a projector screen that is used in combination with a projector that projects a moving image obtained by scanning and outputting a video signal, and that displays the moving image when projection light emitted when the projector projects the moving image,
A roller group including at least a pair of rollers in which long rollers are arranged in parallel;
A screen belt formed of an endless belt that is looped over each roller of the roller group to form a loop trajectory, and forms a screen region that displays the moving image in the loop trajectory between the pair of rollers; ,
Roller drive control means for drivingly controlling the rollers of the roller group so that the screen belt is wound from the upper end side to the lower end side of the screen region along the loop trajectory,
The screen belt is
A band-shaped region formed in a band shape across the width direction of the endless belt, and a remaining region excluding the band-shaped region,
The belt-like area has the property of preventing the projected light that has reached from reaching the viewer of the moving image,
The remaining area has a property of bringing the projected light that has reached the viewer to the projector screen. The projector screen according to claim 1,
The roller drive control means includes
A scanning status signal indicating the status of scanning output of the video signal is received from the projector, or a scanning status signal indicating the status of scanning output is created from a video signal that is equivalently distributed to the video signal input to the projector. A projector screen that controls the driving of the rollers of the roller group based on the scanning status signal and moves the belt-like area in the screen area in synchronization with the scanning output of the video signal. A projector screen according to claim 1 or claim 2, wherein
The remaining area of the screen belt brings the projection light to the viewer side by exhibiting the function of light transmission or light reflection,
The band for the screen belt exhibits a function of absorbing light so that the projection light does not reach the viewer. A projector screen according to any one of claims 1 to 3,
A reflection mirror that reflects projection light emitted when the projector projects the moving image;
The roller group is configured such that the screen region formed by the screen belt between the roller pair is opposed to the reflection mirror so that the reflected light reflected by the reflection mirror reaches, and the loop until the roller pair is reached. So that the trajectory does not block the projection light from the projector while passing through the back of the reflecting mirror,
The remaining area of the screen belt exhibits a light transmission function and transmits the reflected light reaching from the reflection mirror. Projector screen. The projector screen according to claim 4,
With a housing,
The reflective mirror is arranged on the back side of the housing,
A projector screen, wherein the roller pair is disposed on the front side of the casing, and the screen belt in a range forming the screen region on the front side of the casing is opposed to the reflection mirror. A projector screen according to any one of claims 1 to 5,
The screen belt is provided with a plurality of the belt-like regions at equal intervals in the loop trajectory. A projection system,
A projector that projects a moving image obtained by scanning and outputting a video signal;
A projection system comprising: the projector screen according to claim 1, wherein the projector receives a projection light emitted when the projector projects the moving image and displays the moving image. A projector that projects a moving image obtained by scanning and outputting a video signal,
A housing for housing the projector;
A reflection mirror that is disposed on the back side of the housing and reflects projection light emitted when the projector projects the moving image;
A roller group for forming a loop locus with a roller pair in which long rollers are arranged in parallel on the front surface side of the housing, wherein the loop locus until reaching the roller pair is stored in the housing A roller group having a back roller so as to be a trajectory passing through the lower side of the projector and the back of the reflection mirror;
A screen belt comprising an endless belt that is looped over each roller of the roller group to form the loop locus, and the reflection mirror reflects the loop locus between the roller pair on the front side of the housing. A screen belt forming a screen area to which the reflected light reaches,
Roller drive control means for drivingly controlling the rollers of the roller group so that the screen belt is wound from the upper end side to the lower end side of the screen region along the loop trajectory,
The screen belt is
A band-shaped region formed in a band shape across the width direction of the endless belt, and a remaining region excluding the band-shaped region,
The belt-like region has a property of absorbing the reflected light that has reached,
The residual region has a property of transmitting the reflected light that has reached,
The roller drive control means includes
A signal representing the scanning output status of the video signal is received from the projector, and the rollers of the roller group are driven and controlled based on the signal to synchronize the belt-like area with the scanning output of the video signal. A projector that moves in the screen area. The projector according to claim 9, wherein
The screen belt is provided with the belt-like area at a plurality of positions at equal intervals in the loop trajectory.

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