JPH08289237A - Projector system - Google Patents

Abstract

PURPOSE: To prevent trapezoidal distortion from being generated in the case of forming an enlarged display image by providing a distortion correction circuit for outputting a corrected video signal, which is corrected so as to longitudinally and laterally cancel the distortion generated in the display image on a screen by the difference of an optical path from the light source of image light to the screen, as a driving signal for a liquid crystal display means. CONSTITUTION: A trapezoidal distortion correction circuit 10 forms corrected video data S12 to cancel the distortion generated on the screen. The trapezoidal distortion correction circuit 10 performs processing by forming one correction line with a certain number of input lines less than up lines based on a prescribed calculation formula and forming one correction line with a certain number of lines more than down lines while using a linear arithmetic circuit 14. At such a time, the linear arithmetic circuit 14 more improves compressibility in the direction of picture elements toward the lower lines as well. As a result, the trapezoidal distortion correction circuit 10 forms the corrected video data to cancel the trapezoidal distortion both longitudinally (in the direction of lines) and laterally (in the direction of picture elements).

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Field of Industrial Application Conventional Technology (FIGS. 11 and 12) Problem to be Solved by the Invention (FIGS. 11 and 13) Means for Solving the Problem Action Example (FIGS. 1 to 10) (1) 1 Example (2) Second Example (3) Third Example (4) Other Example Effects of the Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projector device, and is suitable for application to an oblique projection type rear projection device installed in, for example, an aircraft.

[0003]

2. Description of the Related Art Conventionally, as a projection apparatus of this type, there is one having a structure shown in FIG. In the rear projection device 1 shown in FIG. 11, the image light L1 emitted from the image light emitting portion 3 of the projector device 2 is reflected by the reflecting mirror 4 and projected on the back surface side of the screen 5, so that the screen 5 It is formed to display an enlarged display image on the front side.

The projector device 2 has a built-in liquid crystal display device (hereinafter referred to as an LCD panel) 6, and emits image light L1 formed by driving the LCD panel 6 with an input image signal. .

As shown in FIG. 12, the back surface of the screen 5 has a sawtooth cross section. The first surfaces 5A parallel to each other are configured to transmit the image light L1, and the second surfaces 5B parallel to each other are image light L1.
It is designed to reflect. As a result, the image light L1 that is obliquely incident on the back surface of the screen 5 is
The image is reflected by the second surface 5B and emitted toward the front surface of the screen 5, and an image based on the image light L1 is enlarged and displayed on the front surface. In practice, the screen 5 is configured to be able to reflect the image light L1 to the front side if the incident angle θ of the image light L1 with respect to the reference surface is within 60 [°].

As described above, the rear projection device 1
Arranges the projector device 2 directly behind the screen 5 by radiating the image light L1 from the projector device 2 arranged below the rear projection device 1 to the screen 5 through the reflecting mirror 4. Compared with the case where the image light L1 is directly emitted to the screen 5, the entire rear projection device 1 can be made thinner, and it can be installed by effectively utilizing a limited space such as an aircraft.

[0007]

However, in the projector apparatus 2 of the oblique projection type as described above, trapezoidal distortion due to the optical path difference from the image light emitting unit 3 to the screen 5 occurs in the display image on the screen 5. There's a problem. For example, in the rear projection apparatus 1 shown in FIG. 11, when the incident light from the reflecting mirror 4 to the screen 5 has an optical path difference above and below the screen 5 due to the oblique incidence of the image light L1 on the screen 5. In addition, as shown in FIG. 13, trapezoidal distortion occurs such that the upper portion is smaller and the lower portion is larger on the screen 5.

In order to avoid this trapezoidal distortion, conventionally, a correction optical system for canceling the optical path difference is provided between the projector device and the screen for optical correction. However, the above method has a drawback that the correction optical system has to be provided in a limited space in the housing. Further, it is practically difficult to form a correction optical system capable of accurately canceling the optical path difference.

Further, as a display device, instead of the LCD panel 6, a cathode ray tube device having three tubes and three lenses (hereinafter, referred to as CR
There is a method of using a projector device according to (T), but since the positions of emitting color image light are different in each of the three lenses, it is necessary to superimpose the color image light emitted from each on the screen (so-called registration). There is. Therefore, there is a problem in that the structure is complicated.

The present invention has been made in consideration of the above points. When an enlarged display image is formed by projecting image light on the screen, trapezoidal distortion that occurs in the image displayed on the screen is eliminated. It is intended to propose a projector device having a simple structure that can avoid and obtain a high quality display image.

[0011]

In order to solve such a problem, in the present invention, the distortion generated in the display image on the screen due to the optical path difference from the light source of the image light to the screen is canceled in the vertical and horizontal directions. The corrected video signal thus corrected is used as the drive signal for the liquid crystal display means.

Further, in the present invention, in addition to the above-mentioned configuration, the screen aspect ratio of the input video signal is converted into an image having a screen aspect ratio that is longer than the screen aspect ratio, and the liquid crystal display means is driven. A wide image forming circuit for outputting as a signal is provided.

Further, according to the present invention, in the projector device for projecting the image based on the image light emitted from the first, second and third cathode ray tube devices onto the screen, the color emitted from the first cathode ray tube device. The image light and the color image light emitted from the second cathode ray tube device are combined and emitted by the first half mirror, and the color image light emitted from the first half mirror and the third image light are emitted. A projection lens that combines the color image light emitted from the cathode ray tube device with the second half mirror and emits the combined image light to enlarge the image light emitted from the second half mirror to a predetermined magnification. To be emitted through.

[0014]

The distortion caused in the display image on the screen due to the optical path difference from the light source of the image light to the screen is corrected by the trapezoidal distortion correction circuit so as to cancel in the vertical and horizontal directions, and the corrected correction is made. The video signal is used as a drive signal for the liquid crystal display means. This makes it possible to display an image in which the trapezoidal distortion that occurs when an enlarged display image is formed by projecting image light onto the screen is corrected not only in the horizontal direction but also in the vertical direction.

Further, after the input video signal is distortion-corrected by the above-mentioned trapezoidal distortion correction circuit, it is converted into a video image having a horizontally long screen aspect ratio with respect to the screen aspect ratio of the video signal inputted by the wide image forming circuit. And outputs it as a drive signal for the liquid crystal display means. As a result, it is possible to display an image in which the input image is distortion-corrected in the vertical direction and the horizontal direction, and it is possible to obtain a high-quality display image with improved resolution and brightness.

Further, in a projector device for projecting an image based on the image light emitted from the first, second and third cathode ray tube devices onto a screen, the color image light emitted from the first cathode ray tube device and the first color image light emitted from the first cathode ray tube device. The color image light emitted from the second cathode ray tube device is combined by the first half mirror, and then the color image light emitted from the first half mirror and the third cathode ray tube device are emitted. Second with color image light
Of the red, green, and blue color image lights to finally obtain image light. Thus, registration can be performed with a simple configuration, distortion of an image displayed on the screen can be corrected, and brightness and image quality before correction can be maintained even after the distortion of the image is corrected.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

(1) First Embodiment A trapezoidal distortion correction circuit 10 shown in FIG. 1 is a projector device 2 in an oblique projection type projection device.
(Fig. 11), the LCD panel 6 (Fig.
Corrected video data for driving the liquid crystal display means of 1) is formed. The trapezoidal distortion correction circuit 10 uses the video signal S1.
Is input to the signal separation circuit 11. The signal separation circuit 11 is
The input video signal S1 is separated into a synchronizing signal, a luminance signal and a color difference signal, and then analog / digital conversion is performed to form synchronizing data S2, luminance data S3 and color difference data S4, and the synchronizing data S2 is stored in the memory control circuit 12. And the luminance data S3 and the color difference data S4 to the memory 13.

The memory 13 has a structure capable of storing one frame of video data, and the memory control circuit 12 produces luminance data S3 and color difference data based on a write control signal S5 formed on the basis of the synchronization data S2. S4 is stored. As a result, the memory 13 stores the luminance data S3 and the color difference data S4 for one frame in line scan order. The data stored in the memory 13 is read by the memory control circuit 12 based on the read address signal S6 formed based on the synchronous data S2.
The luminance data S7 and the color difference data S8 thus read out are sent to the linear operation circuit 14.

The linear operation circuit 14 uses the projector device 2 (see FIG. 1) in advance for the luminance data S7 and the color difference data S8.
1) to the screen 5 (FIG. 11) A correction that cancels the distortion generated on the screen 5 (FIG. 11) based on the optical path difference by performing an operation using a calculation formula set according to the optical path difference. Luminance data S9 and correction color difference data S
Form 10. At this time, the linear operation circuit 14 receives from the memory control circuit 12 a control signal S11 indicating which line of luminance data S7 and color difference data S8 is currently input, and performs an operation according to the control signal S11. That is, since the rate of distortion of the image displayed on the screen 5 (FIG. 11) differs depending on the line, the linear operation circuit 14 forms different correction data to cancel the distortion by performing different operations depending on the line. Actually, the linear arithmetic circuit 14 forms the correction data by increasing the data compression rate in the vertical and horizontal directions at a position where the distance due to the optical path difference of the image light on the screen 5 (FIG. 11) is long. .

Further, the linear operation circuit 14 performs an interpolation process in the operation process so that the LCD panel 6 (see FIG. 1).
The data corresponding to each dot of 1) is formed so that the pixels of the LCD panel 6 (FIG. 11) can be utilized to the maximum extent.

The signal synthesizing circuit 15 outputs the corrected luminance data S9 and the corrected color difference data S1 output from the linear operation circuit 14.
0 and the synchronization data S supplied from the memory control circuit 12
The corrected image data S12 is formed by synthesizing the corrected image data S12 and the corrected image data S12 and is used as a drive signal in the LCD.
Send to panel 6 (FIG. 11).

In the above configuration, the trapezoidal distortion correction circuit 1
0 forms the corrected video data S12 that cancels the distortion generated on the screen 5 (FIG. 11). Here, as shown in FIG. 2, for example, when the input image (FIG. 2 (A)) is used as it is to form a display image and the line below the screen is enlarged (FIG. 2 (B)), The distortion correction circuit 10 forms the corrected video data by increasing the compression ratio of the data in the lower line of the screen with respect to the input video signal (FIG. 2).
(C)). The trapezoidal distortion correction circuit 10 includes a linear operation circuit 14
In the above, the upper line forms one correction line with a smaller number of input lines and the lower line forms one correction line with a larger number of lines, as described above. Perform processing. Further, at this time, the linear operation circuit 14 increases the compression rate in the pixel direction in the lower line.

As a result, the trapezoidal distortion correction circuit 10 forms corrected video data that cancels the trapezoidal distortion in both the vertical direction (line direction) and the horizontal direction (pixel direction). Then, the LCD panel 6 (FIG. 11) is obtained based on the corrected video data.
Drive the projector device 2 (Fig. 11)
Displays an image without distortion in both the vertical and horizontal directions on the screen 5 (FIG. 11) as shown in FIG.
Here, for example, when the distortion correction is performed only in the lateral direction, the projector device 2 (FIG. 11) has a rectangular-shaped apparent distortion on the screen 5 (FIG. 11) instead of the trapezoidal shape as shown in FIG. Display an image as if offset. However, this display image is stretched as it goes downward in the vertical direction (line direction), resulting in a distorted image.

On the other hand, the trapezoidal distortion correction circuit 10 of this embodiment can form a display image having no distortion by correcting distortion in the vertical direction as well as in the horizontal direction. Further, the trapezoidal distortion correction circuit 10 uses the calculation formula of the linear operation circuit 14 when the distortion state on the screen 5 (FIG. 11) is changed by changing the arrangement of the projector 2 and the screen 5 (FIG. 11). Can be dealt with easily without changing other configurations.

According to the above configuration, the screen 5 (see FIG.
1) By correcting the input video signal not only in the horizontal direction but also in the vertical direction so as to cancel the distortion on the screen, a high-quality display image without distortion is displayed on the screen 5 (FIG. 11). Can be projected.

(2) Second Embodiment FIG. 4 shows the configuration of the second embodiment of the present invention. The trapezoidal distortion correction circuit 10 (FIG. 1) described in the first embodiment corrects the input video signal. After forming the corrected video data S12, the corrected video data S12 is sent to the wide image forming circuit 21. The wide image forming circuit 21 sets the corrected image data S12 input from the trapezoidal distortion correction circuit 10 such that the screen aspect ratio on the screen becomes 4: 3 to the screen aspect ratio on the screen of 16: 9. Wide corrected video data S20 is formed by converting the wide corrected video data S20 into various data, and the wide corrected video data S20 is sent to the LCD panel 22 as a drive signal.

The wide image forming circuit 21 forms the wide corrected image data S20 by performing a conversion process for extending the corrected image data S12 in the horizontal direction by the change in the horizontal direction of the screen. Here, the LCD panel 22 is 16: 9.
And an aspect ratio of, and the driving is performed based on the wide corrected video data S20.

In the above-mentioned structure, the LCD panel 22 converts the corrected image data S12 which has been distortion-corrected by the trapezoidal distortion correction circuit 10 into the wide corrected image data S20 by the wide image forming circuit 21, and the wide corrected image data S2.
It is driven by inputting 0 as a drive signal. As a result, an image with a screen aspect ratio of 4: 3 will be displayed with a screen aspect ratio of 1
Converting to a 6: 9 image (FIG. 5) can improve the resolution and brightness of the image in addition to correcting distortion.

That is, in a conventional image having a screen aspect ratio of 4: 3, as shown in FIG. 6, about 30% of the LCD panel is effective pixels, whereas an image having a screen aspect ratio of 16: 9 is displayed. By converting, the number of effective pixels of the LCD panel can be increased up to 50% as shown in FIG. Therefore, by increasing the number of effective pixels, the resolution and brightness of the displayed image can be improved.

According to the above configuration, it is possible to display an image in which the input image is distortion-corrected in the vertical and horizontal directions and to improve the resolution and brightness of the image.

(3) Third Embodiment In the projection device 30 shown in FIG. 8 in which parts corresponding to those in FIG. 11 are designated by the same reference numerals, a projector device 31 is arranged in the lower portion of the housing of the projection device 30. To do.

The CRT projector device 3 shown in FIG.
1, the CRT 41 that emits the blue color image light L2
The CRT 42, which emits the green color image light L3 and the green color image light L3, is arranged in the half mirror 43 at a position where the color image light L2 and the color image light L3 are orthogonal to each other. Also CRT41 and CR
The distance from T42 to the half mirror 43 is an equal distance a. Color image lights L2 and C emitted from the CRT 41
The color image light L3 emitted from the RT 42 forms the color image light L4 registered on the half mirror 43,
It is incident on the half mirror 44 at an angle of 45 °.

The red color image light L5 emitted from the CRT 45 is incident on the half mirror 44 arranged at a distance b from the half mirror 43, and is registered on the half mirror 44 with the above-mentioned color image light L4. To be done. CRT45
Is arranged at a position where the emitted color image light L5 is orthogonal to the color image light L4 and at a position where the distance between the half mirror 44 and a + b is formed, and the color image light L emitted from the CRT 45 is
5 is incident on the half mirror 44 at an angle of 45 [°]. Color image light L4 superimposed on the half mirror 44
And L5 form image light L6, and are emitted to the outside of the projector device 31 via a projection lens 46 formed of a single lens, and are enlarged and projected at a predetermined magnification on the screen.

In the above structure, the CRT 41, the CRT
42 and the color image lights L2 and L3 emitted from the CRT 45.
And L5 are overlapped by the half mirrors 43 and 44, so that the image lights L6 in which the RGB colors are overlapped and registered are emitted to the outside of the projector device 31 via the projection lens 46. As a result, the conventional 3 tubes 3
In the case of a CRT projector device using a lens, the oblique projection type projection method requires a complicated mechanism for registration on the screen, which is not possible in practice.
The projector device 31 has a simple structure using a half mirror, so that the CRT 41, CRT 42, and CRT 45 can be easily installed.
Registration of the color image lights L2, L3, and L5 emitted from the can be performed.

The trapezoidal distortion correction of the emitted image can be easily adjusted by using an existing CRT deflection circuit (not shown). In addition, since the CRT has no equivalent to the number of effective pixels of the LCD panel, it is possible to maintain the brightness and the image quality before the correction even after the keystone correction of the image (FIG. 10). Further, the CRT has a larger size of the light emitter itself than the LCD, but if the depth of the projector device 31 is suppressed to some extent, the size in the vertical and horizontal directions as shown in FIG. The dicing device 30 can be made thin.

According to the above structure, the distortion of the image displayed on the screen can be corrected with a simple structure, and the brightness and the image quality before the correction can be maintained even after the distortion correction of the image.

(4) Other Embodiments In the above-described first embodiment, the case where the rear projection device is used is described, but the present invention is not limited to this, and image light is emitted from the front of the screen such as an OHP. You may use it for what is projected.

In the above-described first embodiment, the case where the calculation formula based on the incident angle of the image light on the screen 5 is set in advance has been described. However, the present invention is not limited to this, and a CPU or the like can be used. When the incident angle on the screen 5 is changed, an arbitrary value may be input from the outside to perform a corresponding calculation, and the compression rate of the video signal may be changed. As a result, even if the incident angle to the screen changes due to a change in the installation location of this device or a change in the arrangement of the reflecting mirror and projector device, it is possible to quickly respond.

Further, in the above-described second embodiment, the case where the wide image forming circuit 21 is arranged at the subsequent stage of the trapezoidal distortion correction circuit 10 has been described, but the present invention is not limited to this, and the preceding stage of the trapezoidal distortion correction circuit 10 is described. The wide image forming circuit 21 may be arranged in the. Even in this case, the same effect as that of the above-described embodiment can be obtained.

In the third embodiment described above, the CRT
41, 42, and 45 have been described in detail as displaying an image with a screen aspect ratio of 4: 3, but the present invention is not limited to this, and a video signal input with a screen aspect ratio of 4: 3 is converted into a screen aspect ratio of 1.
It may be converted into a video signal of 6: 9 and output.

In the third embodiment, the CRT is used.
Although the color of the color image light emitted at 41, 42, and 45 is limited, the present invention is not limited to this, and the order may be changed if the colors of the image light emitted at each CRT do not overlap. For example, the CRT 41 is made to output red color image light instead of blue, the CRT 42 is made to output blue color image light instead of green, and the CRT 45 is made to output green color image light instead of red. Even in this case, the same effect as that of the above-described embodiment can be obtained.

[0043]

As described above, according to the present invention, the distortion caused in the display image on the screen due to the optical path difference from the light source of the image light to the screen is corrected so as to cancel in the vertical and horizontal directions. By providing a distortion correction circuit that outputs the corrected video signal as a drive signal for the liquid crystal display means, it is possible to avoid the trapezoidal distortion that occurs when an enlarged display image is formed by projecting the image light on the screen. .

Further, after distortion correction of the input video signal in the distortion correction circuit, the wide image forming circuit converts the input video signal into a video signal having a horizontally long screen aspect ratio and a liquid crystal display. It is output as a drive signal of the means. As a result, it is possible to display an image in which the input image is distortion-corrected in the horizontal and vertical directions, and it is possible to obtain a high-quality display image with improved resolution and brightness.

Further, in the projector device for projecting an image based on the image light emitted from the first, second and third cathode ray tube devices on the screen, the first cathode ray tube device, the second cathode ray tube device and the The blue color image light, the green color image light and the red color image light emitted from the cathode ray tube device 3 are superposed by the first and second half mirrors and enlarged at a predetermined magnification by the projection lens. Output.
Thus, the distortion of the image displayed on the screen can be corrected with a simple configuration, and the brightness and the image quality before the correction can be maintained even after the image distortion correction.

[Brief description of drawings]

FIG. 1 is a block diagram showing a trapezoidal distortion correction circuit according to a first embodiment.

FIG. 2 is a schematic diagram provided for explaining correction of trapezoidal distortion according to the first embodiment.

FIG. 3 is a schematic diagram provided for explaining correction of trapezoidal distortion according to the first embodiment.

FIG. 4 is a block diagram showing the configuration of the second embodiment.

FIG. 5 is a schematic diagram provided for explaining correction of trapezoidal distortion according to the second embodiment.

FIG. 6 is a schematic diagram showing a ratio of the number of effective pixels of the LCD panel in a screen aspect ratio of 4: 3.

FIG. 7 is a schematic diagram showing a ratio of the number of effective pixels of the LCD panel in a screen aspect ratio of 16: 9.

FIG. 8 is a schematic diagram showing a rear projection device according to a third embodiment.

FIG. 9 is a schematic configuration diagram showing a CRT projector device according to a third embodiment.

FIG. 10 is a schematic diagram showing a CRT correction screen and an LCD correction screen.

FIG. 11 is a schematic diagram showing a configuration of a rear projection device.

FIG. 12 is a schematic diagram for explaining a cross-sectional shape of a screen and incident light.

FIG. 13 is a schematic diagram for explaining trapezoidal distortion of a projected image.

[Explanation of symbols]

1,30 …… Rear projection equipment, 2,31 ……
Projector device, 3 ... Image light emitting part, 4 ... Reflecting mirror, 5 ... Screen, 5A, 5B ... Each surface on the back side of the screen, 6, 22 ... LCD panel, 10 ... Trapezoidal distortion correction circuit, 11 ... Signal separation circuit, 12 ... Memory control circuit, 13 ... Memory, 14 ... Linear operation circuit, 15
...... Signal synthesis circuit, 21 …… Wide image forming circuit, 4
1, 42, 45 ... CRT (blue, green, red), 43, 44
...... Half mirror, 46 …… Single lens projection lens.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H04N 9/31 H04N 9/31 A

Claims (5)

[Claims] 1. A projector apparatus for displaying an enlarged display image on a screen by forming image light according to an input image signal and projecting the image light on a predetermined screen. A liquid crystal display unit that forms the image light according to a signal, and the image signal is input, and distortion generated in the display image on the screen is generated in the vertical direction based on the optical path difference from the light source of the image light to the screen. A projector device comprising: a trapezoidal distortion correction circuit for outputting a corrected video signal formed by correcting the video signal so as to cancel out in the lateral direction as a drive signal for the liquid crystal display means. 2. The trapezoidal distortion correction circuit increases the compression ratio of the image light in the vertical direction and the horizontal direction at a position where a distance due to an optical path difference of the image light on the screen is long, and thus the corrected image is corrected. The projector device according to claim 1, wherein the projector device is configured to form a signal. 3. A wide image forming circuit for forming a video signal by converting a screen aspect ratio of an input video signal into a screen aspect ratio which is horizontally long with respect to the screen aspect ratio, and inputs the input video signal. In addition to the correction by the trapezoidal distortion correction circuit, the wide image forming circuit converts the screen aspect ratio into a horizontally long screen aspect ratio and outputs it as the drive signal to the liquid crystal display means. The projector device according to claim 1. 4. A first cathode ray tube device which emits image light of any one of blue, green and red, and a color image which is emitted from the first cathode ray tube device of blue, green or red. A second cathode ray tube device for emitting color image light other than light;
A third cathode ray tube device that emits color image light other than the color image light emitted by the first or second cathode ray tube device among blue, green, or red, and the first, second, and A projector device for combining color image lights of respective colors emitted from a third cathode ray tube device and projecting an enlarged display image on a predetermined screen, wherein the first cathode ray tube device and the first cathode ray tube device are provided. The color image light emitted from the cathode ray tube device is orthogonal to the color image light emitted, and is arranged at a position equidistant from the intersecting position of the color image light to the first cathode ray tube device. Further, the color image light emitted from the second cathode ray tube device and the color image light emitted from the first cathode ray tube device are orthogonal to each other, and the first cathode ray is formed from a crossing position of the color image light. Placed at a position that is equidistant from the distance to the pipe device. The third cathode ray tube device and the color image light emitted from the first cathode ray tube device and the color image light emitted from the first cathode ray tube device are provided at intersections of the color image light emitted from the first and second cathode ray tube devices. The first half mirror that combines the color image light emitted from the second cathode ray tube device and emits the color image light, and the color image light emitted from the first half mirror and the color emitted by the third cathode ray tube device. A second half mirror which is provided at a crossing position of the image light and which combines the color image light emitted from the first half mirror and the color image light emitted from the third cathode ray tube device and emits the combined light. A projector lens for enlarging the image light emitted from the second half mirror to a predetermined magnification. 5. The first cathode ray tube device, the second cathode ray tube device and the third cathode ray tube device according to claim 1, wherein a screen aspect ratio of an input video signal is a screen aspect ratio which is horizontally longer than the screen aspect ratio. The projector apparatus according to claim 4, wherein the projector apparatus converts the ratio and outputs the converted ratio.