JP2010206671A - Projector and projector system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector that can easily correct distortion of a projected image with high accuracy.
An optical engine comprising an electro-optic modulator that modulates light according to image information, and a projection optical system that projects the light modulated by the electro-optic modulator as an image onto an irradiated surface. A projector includes a correction image generation unit that generates a correction image used for correcting distortion of an image and is configured to be able to change the position and shape of the correction image in an irradiated surface.
[Selection] Figure 1

Description

  The present invention relates to a projector, in particular, a technique for correcting an image projected from a projector, and a projector system.

2. Description of the Related Art In recent years, a configuration has been proposed in which a projector adopts an ultra-short focus projection optical system with a short projection distance. By adopting a projection optical system with an ultra-short focus, the projector can be installed in the immediate vicinity of the screen, so that there is an advantage that a high degree of installation freedom can be realized.
However, because the projector can be installed in the immediate vicinity of the screen, the light projected from the projector will be incident on the screen at a steep angle. There arises a problem that large distortion occurs.
As a method for solving this problem, for example, according to the spatial distortion occurring in the projected image composed of character / graphic data projected on the screen, the display data conversion unit adds it to the character / graphic data according to the distortion direction. By controlling the amount of spatial distortion, character / symbol data displayed on the transmissive display device is subjected to spatial distortion in the opposite direction to the spatial distortion generated in the projection optical system. Patent Document 1 proposes a method in which the screen projection image without distortion is obtained by canceling out the above.

  Another method has also been proposed. In the initial correction mode, a test image signal is supplied from the test image signal generator to the drive circuit via the switching unit, and an optical image corresponding to the test image signal is projected on the screen. This optical image is picked up by a CCD camera. The correction content creating unit creates correction content information indicating the correction content to be performed on the original image signal based on the output of the CCD camera. This information is stored in the correction content storage unit. In the normal mode, the correction execution unit corrects the original image signal according to the correction content indicated by the correction content information stored in the correction content storage unit, and the corrected original image signal is converted into an image signal via the switching device as a drive circuit. Patent Document 2 proposes a method for obtaining a good image with no distortion by supplying the image to

JP-A-2-131282 JP-A-8-271852

  The technique proposed in Patent Document 1 is a method of correcting distortion while monitoring an image by an observer. In order to correct the distortion, correction is performed so as to eliminate the distortion by observing both upper corners of the image projected on the screen or the correction image such as the test pattern. However, when an ultra-short focus projection optical system with a short projection distance is adopted, the observer needs to correct the image for correction while looking up from below, and determines the distortion at the upper corners of the image for correction. For this reason, there has been a problem that the amount of distortion cannot be grasped sufficiently with general visual acuity and the distortion cannot be corrected.

  In the technique proposed in Patent Document 2, since a test image is captured by a CCD and the distortion is corrected by an image processing circuit in the projector, the problem of Patent Document 1 does not occur. However, when this technology employs an ultra-short-focus projection optical system, the light incident angle on the irradiated surface at the upper corners of the test image becomes too large. An imaging optical system with a high CCD and high resolution capability is required. Therefore, in order to satisfy these requirements, it is necessary to increase the size of the imaging optical system, and it is difficult to adopt it practically.

  The present invention is realized as the following forms or application examples so as to solve at least a part of the above problems.

  Application Example 1 A projector according to this application example includes an electro-optic modulation device that modulates light according to image information, a projection optical system that projects light modulated by the electro-optic modulation device onto an irradiated surface, and Is a projector having an optical engine unit including a correction image that is formed so that a correction image used for correcting distortion of the image is generated and the position and shape of the correction image in the irradiated surface can be changed. It has the part.

According to this application example, the correction image is moved to a position where it can be easily seen or the size of the image is reduced even if the image is on a large screen and it is difficult for the observer to recognize the corner of the image. Thus, the entire correction image can be recognized. Thereby, since the observer can correct the distortion of the correction image accurately, the image linked with the correction image is also corrected accurately, and high-precision distortion correction can be performed only by visual observation.
Furthermore, since the observer does not have to move during distortion correction, there is also an effect that the burden on the observer is greatly reduced.

  Application Example 2 In the projector according to the application example described above, the correction image is an image modulated using a part of an electro-optic modulation device.

According to this application example, it is possible to project a correction image at an arbitrary position and shape without changing the configuration of a conventional projector. Thereby, a new function can be realized while maintaining the conventional cost.
Furthermore, since the image and the correction image are modulated using the same electro-optic modulation device, it is not necessary to perform calibration for linking the amount of distortion change between the two, and it is simple and highly accurate and highly reliable. Measurement becomes possible.

  Application Example 3 In the projector described in the application example, the correction image is projected from a second optical engine unit provided in the projector, which is different from the optical engine unit.

According to this application example, since the second optical engine unit different from the optical engine unit of the image can be used, the correction image can be projected without affecting the image projection. As a result, the degree of freedom in projecting the correction image is improved, and the observer can easily customize the correction image, thereby improving convenience.
Furthermore, an optical system different from the optical engine unit can be adopted as the second optical engine unit. As a result, the optimum optical system can be selected for the correction image, and a highly efficient and highly accurate system can be constructed.
In addition, only the second optical engine unit can be used independently without using the optical engine. This improves the convenience of distortion correction and has the effect of saving energy in that no image is projected.
In addition, since the image for correction can be projected on a different area from the image display area on the irradiated surface, the image for correction can be displayed without interrupting or blocking the image even when the image is being displayed. Can project. Thereby, since it can correct | amend, without interrupting the information of an image, the convenience improves.

  [Application Example 4] In the projector according to the application example described above, the projection optical system includes at least one mirror having power.

  According to this application example, by providing the projection optical system with a power mirror, it is possible to project the light modulated by the electro-optic modulation device with an ultra-wide angle. This makes it possible to correct distortion easily and with high accuracy by combining with the application example even when the incident angle of light into the irradiated surface becomes large, and exhibit a more excellent effect. Can do.

  [[Application Example 5] In the projector according to the application example described above, the correction image generation unit arranges the center of gravity of the correction image closer to the projector than the center of gravity of the image in the irradiated surface, and The correction image is generated so that the area of the correction image is smaller than the area of the image within the irradiation surface.

According to this application example, by generating the correction image under the above conditions, the correction image is projected so as to approach the projector side within the irradiated surface. That is, when the observer moves the projector and corrects the distortion, the correction image approaches the observer side. This makes it possible for the observer to recognize the amount of distortion by visual observation while moving the projector by hand, simplifying the adjustment work, greatly reducing the burden for correction, and highly accurate distortion correction. Has the effect of becoming possible.
In addition, since it is not advantageous for the observer that the correction image is displayed in a range other than the application example, it is possible to prevent erroneous operations and the like by limiting the range to the above range, thereby improving reliability. Can be made.

  [[Application Example 6] In the projector according to the application example described above, the projector includes a measurement unit for recognizing a correction image in the irradiated surface.

According to this application example, by providing the measurement unit, it is possible to automatically correct distortion with high accuracy without depending on the visual observation of the measurer. This has the effect of improving distortion correction accuracy and reducing the burden on the viewer for correction.
Furthermore, the correction image can be moved to a position where the distortion can be sufficiently recognized without using a high-resolution image sensor or the like in the measurement unit, so that the measurement unit can be reduced in resolution and the cost can be greatly reduced. Miniaturization is possible.

  [[Application Example 7] The projector system according to the application example includes the projector according to the application example described above and a measurement reference provided in a region where the correction image on the irradiated surface is projected. It is characterized by being.

According to this application example, it is possible to easily correct the distortion simply by matching the measurement standard. Thereby, anyone can correct with high accuracy.
Furthermore, the permanent installation of the measurement standard has the effect of improving the installation of the projector.

  [[Application Example 8] In the projector system according to the application example described above, the measurement reference is removable from the irradiated surface.

  According to this application example, even if the measurement reference is set in the image area in the irradiated surface, it can be removed at the time of image projection. Therefore, the measurement reference does not block the image and image deterioration can be prevented.

1 is a schematic configuration diagram of a projector according to a first embodiment of the invention. 1 is a block diagram illustrating a circuit system of a projector according to a first embodiment of the invention. FIG. 3 is an explanatory diagram of an image processing controller of the projector according to the first embodiment of the invention. FIG. 3 is a diagram illustrating a projector distortion correction method according to the first embodiment of the invention. FIG. 3 is a diagram for explaining a distortion correction menu of the projector according to the first embodiment of the invention. FIG. 3 is an explanatory diagram for moving and enlarging a correction image of the projector according to the first embodiment of the invention. FIG. 3 is an explanatory diagram illustrating a configuration of a projection optical system of the projector according to the first embodiment of the invention. FIG. 4 is an explanatory diagram illustrating a detailed configuration of a projection optical system of the projector according to the first embodiment of the invention. FIG. 3 is a diagram illustrating a relationship between a position of a projector and a distortion amount according to the first embodiment of the invention. The figure which shows the relationship between the maximum half angle of view and distortion which concern on Example 1 of this invention. Explanatory drawing about the shape of the image for a correction | amendment which concerns on the modification 1 of Example 1 of this invention. Explanatory drawing about the aspect-ratio of the image for a correction | amendment which concerns on the modification 1 of Example 1 of this invention. The figure which shows the relationship between the viewing angle and distortion amount which concern on the modification 2 of Example 1 of this invention. Explanatory drawing about the definition of the visual acuity which concerns on the modification 2 of Example 1 of this invention. FIG. 6 is a diagram illustrating a schematic configuration of a projector according to a second embodiment of the invention. FIG. 6 is a block diagram of an optical system of a projector according to a second embodiment of the invention. FIG. 6 is a block diagram of a circuit system of a projector according to a second embodiment of the invention. FIG. 10 is a diagram relating to the projection position of the correction image according to the first modification of the second embodiment. Explanatory drawing about a measurement standard. Explanatory drawing about the measurement part which concerns on Example 3 of this invention. The block diagram explaining the circuit system of a measurement part.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  First, the configuration of the projector of this embodiment will be described. FIG. 1 is a perspective view illustrating an installation example of the projector 10 according to the first embodiment. The projector 10 includes an electro-optic modulation device (not shown) and an optical engine unit including a projection optical system 20. The projection optical system 20 projects the light modulated in accordance with the image signal by the electro-optic modulation device in the projector 10 onto a screen 50 as an irradiated surface installed outside the projector 10. This is a so-called front projection type projector that observes the image 51 by observing diffusely reflected light. Although not shown in FIG. 1, it is assumed that the observer is observing the screen 50 on the projector 10 side.

  FIG. 2 is a block diagram illustrating a schematic configuration of the optical system and the circuit system of the projector 10 according to the present embodiment. As shown in FIG. 2, the projector 10 includes an image signal conversion unit 41, an image processing controller 42, an LCD driver 43, a liquid crystal panel 44 as an electro-optic modulation device, a projection optical system 20, and an illumination optical system. 30, a microprocessor 45, and an input device 46.

  FIG. 3 is a block diagram showing a configuration in the image processing controller 42 in FIG. As illustrated in FIG. 3, the image processing controller 42 includes a frame memory 421, a scaler 422, an OSD generation unit 423, a correction image generation unit 427, a mixer 424, and a distortion correction amount adjustment unit 425. . OSD is an on-screen display.

Next, an image projection operation that is a normal operation of the projector 10 will be briefly described with reference to FIGS. 2 and 3.
In FIG. 2, when the observer gives an instruction to start projection from the input device 46, the instruction is transmitted to the microprocessor 45. The microprocessor 45 controls each component including the image signal conversion unit 41, the image processing controller 42, and the illumination optical system 30 based on the transmitted instruction to perform an image projection operation.
The image signal converter 41 inputs an image signal output from a video player, a television, a DVD player, a Blu-ray player, or an image signal output from a personal computer, and inputs these image signals to the image processing controller 42. Convert to an inputable digital image signal.
The image processing controller 42 has various functions such as a function of writing / reading image data to / from the frame memory 421, an image enlargement / reduction function, a distortion correction function of a projected image, and a correction image generation unit.

  Image data included in the image signal input from the image signal conversion unit 41 is stored in the frame memory 421. The image data read from the frame memory 421 is output to the scaler 422. The scaler 422 enlarges / reduces the image represented by the image data read from the frame memory 421 in accordance with the value of the enlargement / reduction parameter set in the register 426. In addition, the scaler 422 converts the image (original image) represented by the image data read from the frame memory 421 according to the value of the distortion correction parameter set in the register 426 to correct the distortion of the projected image. Transforms into Corrected image data is generated based on distortion corrected image data representing the deformed distortion corrected image.

The OSD generation unit 423 generates an OSD image of the menu image data and outputs it to the mixer 424.
The correction image generation unit 427 generates an image for correction and outputs it to the mixer 424 by instructing the display of the correction image input by the observer and the instruction of the display position through the input device 46 through the microprocessor 45. To do.
The distortion correction amount adjustment unit 425 receives the distortion correction amount input by the observer through the input device 46 and the microprocessor 45, calculates the distortion amount by the distortion correction amount adjustment unit 425, and then stores the distortion correction parameter in the register 426. Send to.
Further, the distortion correction parameter (dotted line portion) is sent from the distortion correction amount adjustment unit 425 to the OSD generation unit 423, and after correcting the OSD according to the distortion correction parameter, the corrected OSD image data is sent to the mixer 424. Similarly, the distortion correction parameter is also sent to the correction image generation unit 427, and after correcting the correction image in accordance with the distortion correction parameter, the corrected correction image data is sent to the mixer 424.

The mixer 424 generates projection image data obtained by combining the corrected OSD image data, the corrected image data for correction, and the corrected image data output from the scaler 422, and outputs the projection image data to the LCD driver 43.
However, when OSD image data is not generated by the OSD generation unit 423 and correction image data is not generated by the correction image generation unit 427, corrected image data is output as projection image data. Also, when outputting the correction image data, the corrected image data may not be input to the mixer.

  In addition to the above-described configuration, the image processing controller 42 corrects the image data so that the display state of the image, for example, brightness, contrast, synchronization, tracking, color density, hue, and the like are in a desired state. Although it has various functions, it is not particularly necessary for the description of the present embodiment, so the description is omitted.

  Returning to FIG. 2, the LCD driver 43 drives the liquid crystal panel 44 based on the projection image data input from the image processing controller 42. Thereby, in the liquid crystal panel 44, the illumination light emitted from the illumination optical system 30 is modulated according to the projection image data. The projection optical system 20 projects light (image light) representing an image modulated by the liquid crystal panel 44 onto a projection surface (irradiated surface). Here, since the image light emitted from the liquid crystal panel 44 represents the image 51, the light modulation area of the liquid crystal panel 44 is regarded as an image formation area for forming the image 51 represented by the projection image data, and this image formation is performed. An image 51 formed in the region is projected onto the screen 50 surface optically conjugate with the liquid crystal panel surface 44 by the projection optical system 20.

Next, a specific distortion adjustment method of this embodiment will be described. Returning to FIG. 1, an image 51 is normally projected on the screen 50. If the positional relationship between the screen 50 and the projector 10 is as designed, an image 51 without distortion is projected on the screen 50.
However, when the positional relationship between the screen 50 and the projector 10 is not arranged as designed, for example, when the screen 50 is inclined with respect to the projector 10 or the projector 10 is installed on a tilted table, the image A large distortion occurs in 51.
In order to correct this distortion, the observer gives an instruction to output the correction image 52 from an input device such as a button or a remote controller on the projector main body (not shown). When receiving a correction image output instruction from the input device 46, the correction image generation unit 427 described with reference to FIG. 3 generates the correction image 52 and displays it on the screen 50.

  Next, when the positional relationship between the screen 50 and the projector 10 is not arranged as designed, two methods will be taken up as a method for the observer to correct image distortion. The first method is a method of correcting distortion by moving the projector 10 itself by an observer. The second method is a method of correcting the image data itself by the image processing controller 42.

First, a method of correcting image distortion by manually moving the projector 10 by the observer, which is the first method, will be described with reference to FIG. FIG. 4 shows a state in which the distortion is corrected while the observer 60 moves the projector 10 by using the correction image 52.
When no distortion occurs, the light beam 201 having the maximum half field angle of the light emitted from the projector 10 passes through the optical path indicated by the solid line and reaches the point A of the correction image 52 on the screen 50. Is inclined with respect to a predetermined position, it passes through the optical path indicated by the dotted line and reaches the point A ′ on the screen 50. That is, the difference between the points A ′ and A becomes the distortion of the correction image 52.

In FIG. 4, for convenience of explanation, the light beam 201 having the maximum half angle of view is a light beam directed toward the maximum height portion A in the vertical direction of the screen 50. In practice, however, as shown by the point A in FIG. A light ray directed to the end point of the correction image 52 furthest away from 20 is shown.
The observer 60 moves the position of the projector 10 in, for example, the left-right direction, the tilt, the height direction, etc. in order to eliminate the distortion of the image 51, so that the point A ′ of the correction image 52 reaches the point A. Thus, the difference between the points A ′ and A is visually reduced. Thus, by eliminating the distortion of the corrected image 52, the distortion of the image 51 displayed on the same liquid crystal panel can be eliminated as a result.

  Further, as a means for correcting the position of the projector 10, in addition to moving the projector 10 in the horizontal direction, height, and rotation direction, four or three points (not shown) on the bottom surface of the projector 10 can be moved up and down independently. A thickness adjusting function may be provided. In addition, a table or the like having a mechanism that can move in the left and right, height, and rotation directions may be arranged on the surface on which the projector 10 is installed.

Next, a method for correcting the image data itself by the second image processing controller will be described.
When the image 51 is distorted, the observer 60 instructs the microprocessor 45 to generate a correction image through the input device 46 shown in FIG. The microprocessor 45 instructs the correction image generation unit 427 to project the correction image 52 on the screen via the mixer 424 and the LCD driver 43.
At this time, the image 51 is not output from the scaler 422. By doing so, visibility is improved during distortion correction, correction efficiency is improved, and correction can be performed with high accuracy.
However, a method of generating image data by outputting the image data from the scaler 422 and combining it with the correction image data may be adopted. In this case, although the above-described effect cannot be obtained, distortion can be corrected while viewing the image 51, so that more intuitive adjustment is possible.

Here, it is assumed that the distortion correction amount adjustment unit 425 has no instruction for the distortion correction amount, and the correction image generation unit 427 outputs the correction image 52 that has not been corrected.
The observer 60 in FIG. 4 grasps that the distortion, which is the difference between the points A ′ and A, has occurred in the correction image 52, and displays the OSD menu on the microprocessor 45 through the input device 46 shown in FIG. Give instructions to display.
The microprocessor 45 instructs the OSD generation unit 423 to generate an OSD image including menu data for distortion correction as shown in FIG. 5, and subsequently instructs the correction image generation unit 427 to generate a correction image. The correction image data is output to the mixer 424. The mixer 424 combines the OSD image data and the correction image data and outputs them to the LCD driver 43.
When the OSD menu and the correction image 52 are projected on the screen, the observer 60 corrects the distortion by moving the slider 53 of the distortion correction menu shown in FIG. 5 left and right. By moving the slider 53, the slider amount is sent to the distortion correction amount adjustment unit 425 through the input device 46 and the microprocessor 45 of FIG. 3, and after calculating the distortion amount there, a dotted line is used as the distortion correction parameter. As shown in the figure, the data is sent to the OSD generation unit 423 and the correction image generation unit 427, and each corrected data is sent to the mixer 424.

The observer 60 corrects the correction image 52 so as not to be distorted by this procedure, and then transmits a confirmation signal to the microprocessor 45 through the input device 46. With this signal, the microprocessor 45 stops transmission of the OSD image data and the correction image data to the mixer 424, and the distortion correction amount adjustment unit 425 determines the final distortion correction amount based on the numerical value obtained from the slider 53. calculate.
Then, the distortion correction amount adjustment unit 425 sends the distortion amount to the register 426 as a distortion correction parameter. The scaler 422 transforms the image (original image) represented by the image data read from the frame memory 421 into a distortion corrected image according to the value of the distortion correction parameter set in the register 426 to correct distortion of the projected image. To do. Corrected image data is generated based on distortion-corrected image data representing the deformed distortion-corrected image, and projected onto the screen in the same manner as described above.

As the distortion correction method, in addition to the distortion correction method as shown in the present embodiment, a method of designating the four vertices of the contour shape of the image to a desired position may be adopted, and other distortion corrections may be adopted. The method may be adopted.
In this embodiment, two methods have been described as the distortion correction method. However, only the first method or the second method may be employed, or both of the two methods may be used in combination. As long as the image 51 and the correction image 52 use the same electro-optic modulation element, any distortion correction method can obtain the same effect as that of the present embodiment described later.

However, in both of the above two methods, the final judgment depends on visual observation. In the case of a projector of a type that projects largely obliquely to the screen as shown in FIG. It may be difficult to visually confirm the difference between points A.
In this case, the observer sends an instruction to move / enlarge the correction image 52 to the microprocessor 45 via the input device 46 shown in FIG. 3, and the correction image generation unit 427 receives the instruction from the microprocessor 45 and performs correction. The image 52 can be moved / enlarged and displayed on the panel.

A specific example is shown in FIG. FIG. 6 shows an example in which the position / size of the correction image 52 is freely changed by the observer in the image 51 projected on the screen. FIG. 6A shows an example in which the correction image 52 is moved in the vertical direction 513 and the horizontal direction 514 with respect to the image 51. Of course, it is possible to move in an oblique direction by combining length and width. FIG. 6B shows an example in which the correction image 52 is enlarged or reduced.
These processes are instructed by the observer using movement / enlargement / reduction information input from the observer from the input device 46 of FIG. 3, such as buttons on a projector or remote control, and the signal is sent to the microprocessor 45. The correction image generation unit 427 performs coordinate conversion of the correction image 52 from the movement / enlargement / reduction amount received from the microprocessor 45 and outputs the result on the panel. By repeating this operation, the observer can freely move the correction image 52 as shown in FIG.

Note that an OSD screen as shown in FIG. 5 may be used together as input assistance for the observer. In this way, even if the observer 60 shown in FIG. 4 is in a state where it is difficult to recognize the corners of the image, the correction image 52 can be corrected by moving it to a position where it can be easily seen or reducing the size. The entire image 52 can be recognized. Thereby, since the observer 60 can correct the distortion of the correction image 52 accurately, the image 51 linked to the correction image 52 is also corrected accurately, and high-precision distortion correction can be performed only by visual observation.
Furthermore, since the observer 60 does not have to move during distortion correction, there is an effect that the burden on the observer 60 is greatly reduced.

Further, since the correction image 52 is modulated by using a part of the electro-optic modulation device (liquid crystal panel 44), the correction image 52 can be placed in any position and shape without changing the configuration of the conventional projector. Can be projected. Thereby, a new function can be realized while maintaining the conventional cost.
Further, since the image 51 and the correction image 52 are modulated using the same electro-optic modulation device, calibration for linking the distortion change amounts of both is not required, and the accuracy and reliability can be easily achieved. High measurement is possible.
However, as a moving condition of the correction image 52, as shown in FIG. 1, the area of the correction image 52 is projected onto the screen 50 so as to be smaller than the area of the image 51, and the center of gravity Gm of the correction image 52 is It is desirable to project from the center of gravity Gi of the image 51 closer to the side closer to the projector 10 in the screen 50.

  By generating the correction image under the above conditions, the correction image is projected so as to approach the projector side within the irradiated surface. That is, when the observer moves the projector and corrects the distortion, the correction image approaches the observer side. This makes it possible for the observer to recognize the amount of distortion by visual observation while moving the projector by hand, simplifying the adjustment work, greatly reducing the burden for correction, and highly accurate distortion correction. Has the effect of becoming possible.

In addition, since it is not advantageous for the observer to display the correction image in a range other than the present embodiment, it is possible to prevent erroneous operations and the like by limiting the range to the above range, thereby improving reliability. Can be made.
In FIG. 1, since the projector 10 is arranged on the floor surface, the correction image 52 is shifted in the floor surface direction along the screen 50, but when the projector 10 is arranged on the ceiling surface, The correction image 52 is projected along the screen 50 so as to shift in the ceiling direction.

  By the way, in this embodiment, as shown in FIG. 1, an example is shown in which the projector 10 that projects largely obliquely to the screen 50 and is close to the screen 50 is shown. In the case of such a projector 10, in general, the projection optical system 20 is often provided with at least one mirror having power.

  A projection optical system having a mirror will be described with reference to FIGS. FIG. 7 shows a ray diagram of FIG. 1 viewed from the side. As shown in FIG. 7, the projection optical system 20 is disposed in the projector 10 so that the normal direction of the screen 50 and the optical axis are parallel to each other. Further, the projection light is emitted from the top surface side of the projector 10 (upward in FIG. 7) and reaches the screen 50. The light applied to the screen 50 is diffusely reflected on the surface of the screen 50 and is recognized as an image by the observer 60 who is viewing on the projector 10 side.

FIG. 8 is an enlarged view of the projector 10 portion of FIG. As shown in FIG. 8, the liquid crystal panel 44 is arranged so as to be shifted in parallel to the screen 50 side with respect to the optical axis 204, and the light modulated by the liquid crystal panel 44 is shifted with respect to the optical axis 204. Then, the light enters the projection optical system 20. Here, the liquid crystal panel 44 and the screen 50 have an optically conjugate relationship, and an image displayed on the liquid crystal panel 44 is projected as an enlarged image on the screen 50 via the projection optical system 20. As described above, the liquid crystal panel 44 also has a function as an electro-optic modulation device for a correction image.
Although only one liquid crystal panel 44 is shown in FIG. 8, this is for convenience of explanation, and actually there are three color liquid crystal panels, all of which are shifted in the same amount and in the same direction. ing.

The projection optical system 20 includes a lens unit 202 and a mirror unit 203 having power, and all the optical elements are designed to be rotationally symmetric with respect to the optical axis 204.
Although all the optical elements are rotationally symmetric with respect to the optical axis 204 here, all or part of the lens unit 202 may be designed to be non-rotational symmetric, or the mirror unit 203 may be non-rotational symmetric. It may be designed to. Further, some or all of the optical axes of each optical element of the projection optical system 20 may not be the same. Further, in FIG. 8, the lens unit 202 and the mirror unit 203 are configured. However, only the lens unit 202 or only the mirror unit 203 having power may be configured.

  The mirror unit 203 can be configured by forming a reflective film on a base material having an aspherical shape. As a base material, it can comprise with resin, such as a polycarbonate, for example. Moreover, the reflectance of 95% or more is securable by using the reflective film comprised by vapor-depositing aluminum on a base material. In addition, a dielectric multilayer film or the like can be used as the reflective film. Further, a protective film having a transparent member may be formed on the reflective film.

In FIG. 8, the mirror unit 203 is composed of a single concave mirror, but there may be a plurality of mirrors or a convex mirror.
In the case of the proximity projection optical system using such a mirror, as can be seen from FIG. 7, the projector 10 is arranged at the edge of the screen 50 because the light is emitted at an angle close to parallel to the screen 50 surface. There are many cases. Therefore, since the distance between the observer and the image corner on the screen 50 is extremely large, it is impossible for a general observer to visually recognize the distortion.
Moreover, in the case of such a projector 10, the installation accuracy of the main body of the projector 10 is very sensitive to distortion.

FIG. 9 is a diagram for explaining the relationship between the installation accuracy and distortion of the main body of the projector 10 when the image 51 is projected onto the screen 50 at the projection distance L and the maximum half angle of view θ from the projector 10.
When the projector 10 is rotated by β ° about the axis parallel to the screen 50, the distortion of the image 51 can be expressed by the following formula (1).

FIG. 10 shows the relationship between the distortion (%) and the maximum half angle of view θ when rotated by β ° using the equation (1).
From FIG. 10, it can be seen that as the maximum half angle of view θ increases, the distortion suddenly increases and becomes very sensitive to rotation even if the projector is rotated a little. For example, a distortion of slightly over 5% occurs only by tilting a projector having a maximum half angle of view θ = 80 °, which is generally called an ultra-wide angle, by 0.5 °.

As described above, by providing at least one mirror with power in the projection optical system of the projector, it is possible to project at a short projection distance, and in exchange for the advantage of greatly improving the installability of the projector, the observer And the corners of the image are extremely separated from each other, which makes it difficult to make visual adjustments, makes the installation accuracy very sensitive to distortion, and makes adjustment difficult.
For this problem, according to the present embodiment, even if the observer is in a state where it is difficult to recognize the corners of the image, by moving the correction image to a position where it can be easily seen, or by reducing the size, The entire correction image can be recognized. Thereby, since the observer can correct the distortion of the correction image accurately, the image linked with the correction image is also corrected accurately, and high-precision distortion correction can be performed only by visual observation.

Furthermore, since the observer does not have to move during distortion correction, there is also an effect that the burden on the observer is greatly reduced.
As described above, if a proximity optical system including at least one mirror having power is employed in the projection optical system of the projector, the problem can be solved while maintaining the advantages of the proximity optical system, and a greater effect is produced.

(Modification 1)
In FIG. 1, the correction image 52 has a shape substantially similar to the image 51, but the correction image 52 may be any figure that can recognize the distortion of the image 51. For example, the correction image 52 is composed only of lines and circles. It may be a test pattern, a combination thereof, or a test pattern such as an image.
Further, as the correction image, as shown in FIG. 11A, the correction image 52 is a rectangle surrounded by the correction image vertical line 523 and the correction image horizontal line 524, and the correction image vertical line 523 and the image The vertical lines 511, the correction image vertical lines 524, and the image horizontal lines 512 may be arranged in parallel.
As shown in FIG. 11B, the correction image 52 includes vertical grid lines 525 and horizontal grid lines 526. The vertical grid lines 525, image vertical lines 511, horizontal grid lines 526, and image horizontal lines. 512 may be arranged in parallel.
In this way, by making the straight lines that make up the image for correction parallel to the frame of the image, it becomes possible to adjust the distortion simply by adjusting the parallelism in the vertical and horizontal directions when correcting the distortion. Highly accurate correction is possible.

  Further, as shown in FIG. 12, the aspect ratio of the frame surrounding the correction image 52 can be made the same as the aspect ratio of the image 51. That is, it may be arranged so that the relationship of the following formula (2) is established.

  In this way, since the correction image is a reduced image of the image, it becomes easier for the observer to understand intuitively when correcting the distortion, and the burden of the distortion correction on the observer is reduced.

(Modification 2)
Further, the movement and projection range of the correction image can be prevented from being moved / projected to a position where it is difficult to discriminate distortion with a general observer's eyesight. FIG. 13 is a diagram illustrating the relationship between the visual acuity of the observer and the amount of distortion that can be determined.

The projector 10 is installed at a position separated from the screen 50 by the projection distance L, and the correction image 52 is projected at the maximum half angle of view θm.
As in FIG. 4, when no distortion occurs, the light beam 201 having the maximum half angle of view out of the light emitted from the projector 10 passes through the optical path indicated by the solid line and reaches the point A on the screen 50. However, when the projector 10 is deviated from the predetermined position, it passes through the optical path indicated by the dotted line and reaches the point A ′ on the screen 50. ΔH, which is the difference between point A and point A ′, is the amount of distortion.
The observer 60 corrects the position of the projector 10 so that the distortion amount ΔH is eliminated. In order for the observer 60 to recognize the distortion amount ΔH, the viewing angle of the observer 60 corresponding to the distortion amount ΔH shown in FIG. A visual acuity corresponding to αeye is required. In other words, the observer 60 cannot recognize a visual angle less than the visual angle αeye determined by visual acuity, and the distortion amount ΔH corresponding to the visual angle αeye is the limit resolution of the distortion amount ΔH that can be recognized by the observer 60. I mean.

  Next, the minimum value of the viewing angle αeye that can be recognized by the observer 60 is defined. FIG. 14 shows the relationship between visual acuity and viewing angle αeye. The visual acuity is generally defined by the relationship between the C-shaped Landolt ring 602 on the left in FIG. 14 and the distance Leye of the eye 601 on the right in FIG. FIG. 14 shows a standard size Landolt ring, in which the outer diameter of the ring is 7.5 mm, the thickness of the ring, and the width t of the cut is 1.5 mm. When the Landolt ring 602 is viewed from the position of the distance Leye = 5 m with the eyes 601, the visual acuity when the cut width t = 1.5 mm can be recognized is defined as 1.0. Since the viewing angle αeye at this time can be calculated by the following equation (3), if the width t = 1.5 mm and the distance Leye = 5 m are substituted, the viewing angle αeye becomes 1.0 minute.

Here, when the general visual acuity is 0.7, the Landolt ring is 1 / 0.7 times, so when applied to the equation (3), the viewing angle αeye is 1.47 minutes. Note that the general visual acuity is defined as 0.7 here, but this visual acuity is defined as the minimum visual acuity necessary for obtaining a driver's license. It can be used as a general indicator.
However, 1.47 minutes of the viewing angle αeye obtained here is the limit visual acuity that can recognize the width of the cut of the Landolt ring 602, and corresponds to the limit resolution as described above. Referring back to FIG. 13, the viewing angle αeye obtained by the equation (3) is a limit value for determining whether or not the distortion amount ΔH has occurred. The visual acuity to be corrected is insufficient. Simply, in order to be able to correct the distortion amount ΔH with an error of about ± 10%, the viewing angle αeye needs a viewing angle of 14.7 minutes which is at least 10 times that.
Since the size of the viewing angle αeye changes depending on the sitting height h of the observer 60, so that it can be applied to any sitting height condition, from now on, the discussion proceeds with the sitting height h = 0, and the viewing angle α = αeye at that time explain. Here, the maximum half angle of view θm is obtained from the following equation (4).

Here, H indicates the maximum image height of the projection optical system. In FIG. 13, for convenience, the portion corresponding to the height of the correction image 52 is shown. In practice, however, the correction is performed as described above (FIG. 1). The distance to the upper corner A of the work image 52 is shown.
Moreover, the relational expression regarding the viewing angle αeye of the observer 60 is represented by the following expression (5).

  Here, if the distortion amount ΔH is 1% or less, it is a numerical value that the observer 60 does not care about the distortion of the correction image 52. Therefore, when substituting into the equation (5), the following equation (6) is obtained.

  Further, when formulas (4) and (6) are modified and arranged, the following formula (7) is obtained.

Here, if a person with a visual acuity of 0.7 described above substitutes the viewing angle αeye = 14.7 for correcting the distortion amount ΔH into α and solves with the maximum half angle of view θm, the maximum half angle of view θm becomes 60.60. It becomes 25 degrees.
Therefore, the maximum half angle of view θm of the correction image 52 is expressed by the following formula (8).

Since the maximum half angle of view is an incident angle when viewed from the screen, by making this incident angle 60 ° or less, anyone can visually recognize the distortion amount ΔH and create a correction image that can visually correct the distortion. realizable.
Specifically, a description will be given using the first embodiment. The projection optical system according to the first exemplary embodiment is a fixed focus optical system that does not have a zoom mechanism. Further, the maximum incident angle on the screen is about 75 °, and when the image is projected on the screen, it is difficult to correct the distortion at the corner of the image with the visual acuity of the observer from the equation (8).
Since this projection optical system has a fixed focus, the maximum incident angle on the screen does not change regardless of the projection distance of the projector. Therefore, when the correction image is projected, the position on the liquid crystal panel and the incident angle on the screen are uniquely determined. Therefore, when the observer tries to move the correction image to a position where it enters the screen at 60 ° or more, the microprocessor 45 shown in FIG. 3 stops the signal to the correction image generation unit 427. It is good to do so.

  In this way, by limiting the maximum half angle of view of the light beam for projecting the image for correction to 60 ° or less and preventing the image for correction from being projected beyond that, the observer can always visually observe the image. The amount of distortion can be fully recognized. Accordingly, it is possible to prevent an erroneous operation and the like, and it is possible to improve reliability. In addition, since the observer is not required to have a high degree of visual acuity, there is an effect that the burden on the observer for correction is greatly reduced.

Even if the projection optical system has a zoom mechanism, if the focal length is known, the position on the liquid crystal panel and the incident angle on the screen can be calculated. Therefore, the relationship is preset in the microprocessor 45 in advance, and a focal length reading unit such as an encoder is installed in the zoom mechanism unit of the projection optical system, so that the maximum incident angle is automatically corrected to 60 °. The work image may be moved.
By doing so, it is possible to display a correction image that can be visually adjusted and is closest to the image size, and thus it is possible to correct image distortion with higher accuracy.

  FIG. 15 is a perspective view illustrating an installation example of the projector 10 according to the second embodiment. FIG. 16 is a block diagram of an optical system of the projector 10 according to the present embodiment. FIG. 17 is a block diagram of a circuit system of the projector 10 according to the present embodiment. The projector 10 is a front projection type projector having the same optical system as that of the first embodiment.

As shown in FIGS. 15 and 16, the projector 10 includes a second projection optical system 21 that is a second optical engine unit, a second liquid crystal panel 48, and a second illumination optical system 31. Yes. As shown in FIGS. 16 and 17, the signal output from the correction image generating unit 427 passes through the second LCD driver 47 and drives the second liquid crystal panel 48 based on the correction image data. As a result, the second liquid crystal panel 48 modulates the illumination light emitted from the second illumination optical system 31 according to the projection image data.
The second projection optical system 21 projects light (image light) representing a correction image modulated by the second liquid crystal panel 48 onto a projection surface (irradiated surface). Other operations are the same as those in the first embodiment, and a description thereof will be omitted.
Since the second optical engine unit different from the optical engine unit of the image can be used, the correction image can be projected without affecting the image projection. As a result, the degree of freedom in projecting the correction image is improved, and the observer can easily customize the correction image, thereby improving convenience. Further, by projecting the correction image at a higher resolution than the image, high-precision correction can be performed.

  Furthermore, an optical system (electro-optic modulation device) different from the optical engine unit can be adopted as the second optical engine unit. For example, since the second optical engine unit only needs to display a correction image, it is not necessary to support three colors as in the first embodiment, and the second optical engine unit may be a single color. A single color projector may be used. Further, the spatial light modulation device of the second optical engine unit may be configured such that the correction image can be moved mechanically and optically by a transmission plate on which the correction image is drawn. Furthermore, a scan type projector using a tilt mirror device that scans the entire screen vertically and horizontally may be used for the second optical engine unit.

As a result, the optimum optical system can be selected for the correction image, and a highly efficient and highly accurate system can be constructed.
In addition, only the second optical engine unit can be used independently without using the optical engine. This improves the convenience of distortion correction and has the effect of saving energy in that no image is projected.
In addition, since the image for correction can be projected on a different area from the image display area on the irradiated surface, the image for correction can be displayed without interrupting or blocking the image even when the image is being displayed. Can project. Thereby, since it can correct | amend, without interrupting the information of an image, the convenience improves.
Further, since the distance between the projection optical system and the second projection optical system is large, moire fringes are generated between the image and the correction image when the screen is uneven. As a result, it is possible to add a function for evaluating unevenness on the screen, and to enable more accurate distortion correction.

(Modification 3)
FIG. 18 is a perspective view illustrating an installation example of the projector 10 according to the modification of the second embodiment. As shown in FIG. 18, the projector 10 includes a second projection optical system 21, and the second projection optical system 21 projects a correction image 52 on a screen 50 from a second optical engine unit (not shown). Have a role to play. However, the correction image 52 is projected on the screen 50 below the image 51 that does not overlap the image 51.

  In this way, by projecting the correction image onto an area that does not overlap with the image, it is possible to correct distortion without interrupting the image even while the image is being displayed. Therefore, convenience is improved. The projection location of the correction image is not limited on the screen, and may be on the second object. Further, the projection position of the correction image is not limited to the lower part of the screen.

  FIG. 19 is a perspective view of an installation example when a measurement reference is provided in the modification of the second embodiment. As shown in FIG. 19, the correction image 52 is projected on a screen 50 below the image 51 that does not overlap the image 51. A measurement standard 521 is drawn on the screen 50 as a reference line parallel to a part of the correction image 52. The observer can finally correct the distortion of the image 51 by combining the measurement standard 521 on the screen 50 and the correction image 52.

  In this way, by preparing the measurement standard in an area different from the display area of the image, it is possible to prevent image degradation caused by setting the measurement standard in the image area and not obstructing the viewer's information. Improves. Furthermore, distortion can be easily corrected by just matching the measurement standard, and anyone can correct it with high accuracy. In addition, since the measurement standard is installed outside the screen, the measurement standard can be permanently installed, and the installation for correcting the projector is improved. In FIG. 19, a cross mark is used as a measurement standard. However, any measurement standard may be used as long as distortion can be determined.

In FIG. 19, the measurement reference 521 is provided in an area that does not overlap the image 51, but may be provided in an overlapping area. In this case, as the second optical engine, it is necessary to use invisible light (infrared rays / ultraviolet rays, etc.) as the light source, and to use a substance induced by them (for example, a fluorescent material in the case of ultraviolet rays) as the measurement standard 521. . In this way, since the measurement standard appears only when the correction image 52 is projected, the same effect as described above can be obtained. Alternatively, a measurement standard that uses polarized light and reacts only in a specific polarization direction may be provided.
Furthermore, when the measurement reference is provided in a region overlapping the image 51, it can be made removable after the measurement. Since the measurement standard can be removed from the irradiated surface, even if the measurement standard is set in the image area, it can be removed at the time of image projection, so that the measurement standard does not block the image and image degradation can be prevented.

  FIG. 20 is a perspective view illustrating an installation example of the projector 10 according to the third embodiment. The projector 10 is a front projection type projector having the same optical system as that of the first embodiment.

Normally, the image 51 is projected on the screen 50, but the correction image 52 is projected by the observer's judgment only when the image 51 is distorted, such as when the projector 10 is initially installed. Is projected more.
As shown in FIG. 20, the projector 10 includes a measurement unit 70, and images the correction image 52 projected on the screen 50 along the optical path indicated by the bold line.
FIG. 21 is a block diagram showing only a portion necessary for captured image processing. The measurement unit 70 includes an image sensor 701 and a captured image processing unit 702. The captured correction image 52 is converted into an electrical signal by the image sensor 701, and the distortion amount is digitized by the captured image processing unit 702.

Next, a specific processing procedure will be described.
When a distortion correction instruction is input to the microprocessor 45 by the observer via the input device 46, the microprocessor 45 instructs the correction image generation unit 427 to generate a correction image, and as a result, on the screen. A correction image is displayed.
At this time, the microprocessor 45 calculates a panel area corresponding to the recognizable limit incident angle calculated from the resolution of the image pickup device 701 preset in advance, and the correction image 52 is placed within the panel area. Is displayed.

The image sensor 701 captures the correction image 52, converts it into an electrical signal, and sends it to the captured image processing unit 702. The captured image processing unit 702 calculates a distortion amount based on the image signal, and this data is sent to the distortion correction amount adjusting unit 425 via the microprocessor 45. The distortion correction amount adjustment unit 425 sends the distortion amount as a distortion correction parameter to the correction image generation unit 427. The correction image generation unit 427 that has received the distortion correction parameter sends the corrected image for correction to the mixer 424 and projects the corrected correction image 52 on the screen 50 again. The image sensor 701 again captures the correction image 52. This procedure is repeated until the allowable distortion amount set in the microprocessor 45 is reached.
When the amount is less than the allowable distortion amount, the microprocessor 45 stops transmitting the correction image data to the mixer 424, and the distortion correction amount adjustment unit 425 sends the final distortion correction parameter to the register 426. In this way, the image 51 whose distortion has been automatically corrected can be projected on the screen.

According to the present embodiment, by providing the measurement unit, it is possible to automatically correct distortion with high accuracy without depending on the visual observation of the measurer. This has the effect of improving distortion correction accuracy and reducing the burden on the viewer for correction.
Furthermore, the correction image can be moved to a position where the distortion can be sufficiently recognized without using a high-resolution image sensor or the like in the measurement unit, so that the measurement unit can be reduced in resolution and the cost can be greatly reduced. Miniaturization is possible.

  In this embodiment, as a distortion correction method, a method of correcting the image data itself by the image processing controller is adopted, but a correction function for physically moving the projector body using a motor, a solenoid or the like is adopted. You may do it. Even in this case, in addition to the same effect as described above, there is an effect that even if the positional relationship between the projector and the screen is largely deviated, correction can be performed with high resolution without depending on image processing.

  The projector of each embodiment may use, for example, a solid light emitting element such as a light emitting diode element (LED) instead of the ultrahigh pressure mercury lamp. The projector is not limited to a so-called three-plate projector provided with three transmissive liquid crystal display devices, and may be, for example, a projector using a reflective liquid crystal display device or a projector using a tilt mirror device. The projector may use a projection device (for example, GLV (Grating Light Valve)) that controls the direction and color of light using the diffraction effect of light. Further, when a tilt mirror device is used, it may be a scanning projector that scans the entire screen vertically and horizontally. In this case, the projection optical system described in each embodiment is not necessary, but if the projector has a projector function, the same effects as in this embodiment can be obtained by implementing the present invention. It is not limited.

  In each embodiment, the projector is shown as a box, but may be incorporated in furniture or another device. Further, it may be a projector that projects from the back.

  As described above, the correction image generation unit according to the present invention is particularly useful when used in a projector having a short projection distance.

  DESCRIPTION OF SYMBOLS 10 Projector, 20 Projection optical system, 21 2nd projection optical system, 30 Illumination optical system, 31 2nd illumination optical system, 41 Image signal conversion part, 42 Image processing controller, 43 LCD driver, 44 Liquid crystal panel, 45 micro Processor, 46 input device, 47 second LCD driver, 48 second liquid crystal panel, 50 screen, 51 image, 52 image for correction, 53 slider, 60 observer, 70 measuring section, 201 light beam with maximum half angle of view, 202 lens unit, 203 mirror unit, 204 optical axis, 421 frame memory, 422 scaler, 423 OSD generation unit, 424 mixer, 425 distortion correction amount adjustment unit, 426 register, 427 correction image generation unit, 511 image vertical line, 512 Image horizontal line, 513 vertical direction, 514 Right, 521 metric 523 correction image vertical line, 524 correction image horizontal line, 525 vertical grid lines, 526 horizontal grid lines, 602 Landolt, 601 orders, 701 imaging device, 702 a captured image processing unit.

Claims (8)

A projector having an optical engine unit including: an electro-optic modulation device that modulates light according to image information; and a projection optical system that projects light modulated by the electro-optic modulation device as an image onto an irradiated surface. ,
A projector comprising: a correction image generation unit configured to generate a correction image used for image distortion correction and to change the position and shape of the correction image in the irradiated surface. .   The projector according to claim 1, wherein the correction image is an image modulated using a part of the electro-optic modulation device.   The projector according to claim 1, wherein the correction image is projected from a second optical engine unit provided in the projector, which is different from the optical engine unit.   The projector according to any one of claims 1 to 3, wherein the projection optical system includes at least one mirror having power. The correction image generation unit
In the irradiated surface, the center of gravity of the image for correction is arranged closer to the projector than the center of gravity of the image,
5. The correction image is generated so that an area of the correction image is smaller than an area of the image in the irradiated surface. 6. Projector.   The projector according to any one of claims 1 to 5, further comprising a measurement unit for recognizing the correction image in the irradiated surface. A projector according to any one of claims 1 to 6;
And a measurement reference provided in a region where a correction image on the irradiated surface is projected.   The projector system according to claim 7, wherein the measurement reference is removable from the irradiated surface.