JP2005025113A - Projection type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection type display device which possesses a high copyright protective function, which is made simple and whose portability is excellent. <P>SOLUTION: An infrared ray projection mechanism 3 to project infrared rays IR to be superposed on a projected image V is integrally provided in the projection type display device 1 to project the image V on a screen S. The infrared ray projection mechanism 3 is integrally handled with the projection type display device 1, so that portability is made excellent. The infrared ray projection mechanism 3 is installed at a coaxial position with the projection type display device 1 when the display device 1 is installed, so that installation work can be simplified. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a projection display device for displaying moving image data such as presentation data and movies, and more particularly to a projection display device having a copyright protection function.

  Projectors that irradiate screens with image light and display images on screens are widely used for electronic presentations and movie viewing because of their performance and ease of use, and their compatibility with digital devices such as computers. I have done it. It is also recognized as the core device for home theater at home. By the way, in recent years, the existence of pirated versions of movie software has become a problem. A pirated version is an illegal copy of a work such as a movie or presentation data. When these pirated copies are distributed, the profits of the copyright holders are lost, which causes serious problems such as obstacles to sound cultural creation activities and leakage of trade secrets. Furthermore, with the recent development of information technology, pirated editions have been digitized and can be easily mass-produced on personal computers and can be easily distributed worldwide via the Internet. For this reason, various mechanisms for protecting the rights of copyright holders have been proposed. For example, as a technique for protecting the copyright of an image file or the like, there is a technique for processing the image file itself such as a digital watermark technique or a copy guard technique.

  Although this technology is very good, images projected by a projector or image data displayed on a CRT are projected by a digital video camera, a digital camera, or a CCD camera built in a mobile phone. If the image is shot (voyeurism), no matter how strong digital watermarking technology or copy guard technology is applied, if the image displayed on the screen is recorded, Anti-duplication technology is useless. Therefore, in Patent Document 1, an image (hereinafter referred to as an infrared image) is projected by an infrared projector on an image projected on a screen by an infrared projector, whereby the image projected on the screen is converted into a digital video or digital image. A technique has been proposed in which an infrared image is captured in a captured image even when the image is captured by a camera. According to the technique of this Patent Document 1, if a desired image is projected, an infrared image is projected on top of the projected image, so that even if the projected image is voyeurized, the captured image remains. It can be immediately determined that the copy is illegal, and the quality of the image itself is lowered, so that the commercial value is lowered.

In the technique of Patent Document 2, when the reflectance of the screen is low, the amount of reflected infrared light projected on the screen is reduced, and in order to prevent the infrared image in the voyeurized image from becoming inconspicuous, There has been proposed a technique in which an outside image is projected toward the viewer side, and an infrared image is directly incident on a camera or the like for voyeurism.
US Pat. No. 6,018,374 JP 2002-341449 A

  The technique of superimposing an infrared image on the image projected on the screen in this way is effective for voyeurism by a CCD imaging device or the like. However, in the technique disclosed in Patent Document 1, an infrared image is separated from a projector that projects an original image. A projector to project is necessary, at least two projectors are necessary, and it is essential to superimpose an infrared image on the main image. Also in the technique of Patent Document 2, a projector or the like for projecting infrared rays toward the viewer side is required. As described above, the techniques of Patent Documents 1 and 2 have the following three problems.

  The first problem is a problem of manufacturing a projector that projects an infrared image. There are three types of projectors: a cathode ray tube type, a liquid crystal type, and a DMD (digital micromirror) type. The cathode ray tube type utilizes a phenomenon in which the phosphor emits light by colliding accelerated electrons with the phosphor. Therefore, in order to project an infrared image with a cathode ray tube type projector, a cathode ray tube that emits infrared rays is necessary, but there is a problem in the feasibility. Further, in a liquid crystal type or DMD type projector, infrared rays or ultraviolet rays are removed from a light beam emitted from a light source in order to ensure the reliability of the projector. Since infrared rays have a heat generating action, when light containing infrared rays is irradiated onto a display device such as a liquid crystal panel or DMD, the temperatures of the display devices and components arranged in the vicinity thereof are increased. As a result, the life of the parts is significantly reduced. Therefore, projecting infrared images with a conventional liquid crystal type or DMD type projector is extremely risky and problematic.

  The second problem is that the method of superimposing an infrared image on the main image is extremely inconvenient. Since an infrared image cannot be recognized by humans, the projection position of the infrared image cannot be adjusted so that the infrared image is visually superimposed on the main image. For this reason, it has to be confirmed by using a camera capable of projecting infrared rays, which is troublesome to install.

  The third problem is that it uses two projectors and lacks portability. When using a projector for a presentation, etc., it is necessary to carry two projectors and an infrared camera each time a presentation is performed by moving to a different location, and to align the infrared image with the infrared camera each time it is installed. In this technology, portability was not considered at all, which was a problem.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a simple and portable projection display device that enables an infrared image to be superimposed on a projected image in order to protect copyright.

  The present invention is characterized in that in a projection display device that projects an image on a screen, an infrared projection mechanism that projects an infrared ray superimposed on the projection image projected on the screen is integrally provided. Here, the infrared projection mechanism is disposed around a projection lens that projects an image of the projection display device. Alternatively, the infrared projection mechanism is disposed around a projection mirror that projects the image of the projection display device.

  As described above, according to the present invention, since the infrared projection mechanism for projecting the infrared ray to be superimposed on the projected image is integrated with the projector in order to protect the copyright, the advanced copyright is simple and excellent in portability. A projection display device having a protection function is provided.

  In the present invention, it is preferable to use an infrared semiconductor laser as a light source of the infrared projection mechanism. Alternatively, an infrared LED is used as the light source of the infrared projection mechanism. The infrared projection mechanism preferably includes a scanning mechanism for scanning the infrared light on an image. Furthermore, the infrared light is preferably continuous light or discontinuous light.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an external perspective view of a projection display apparatus according to a first embodiment of the present invention, and FIG. 2 is a schematic configuration diagram showing an internal configuration thereof. Here, the projection display device is configured as a DMD projector, and the projector 1 is built in a casing 2. That is, the white light emitted from the light source 11 composed of an ultra-high pressure mercury lamp or the like is reflected by the reflecting mirror 12, collected by the condenser lens 13, and focused on the incident end face of the integrator rod 14 made of quartz or the like. , And enters the integrator rod 14. When the light incident on the integrator rod 14 is incident on the color wheel 15 and is transmitted, the red, green, and blue colors are separated in a time-sharing manner, and the red, green, and blue colors are separated into the respective colors. Are incident on the total reflection prism 17 by the condenser lens 16. Each color light incident on the total reflection prism 17 is totally reflected and reaches the DMD panel 18. The light incident on the DMD panel 18 is modulated in accordance with an image signal applied to the DMD panel 18, and again passes through the total reflection prism 17 as light representing the image (projection light) toward the projection lens 19. Thus, the image is formed, and the formed image V is displayed on the screen S.

  An infrared projection mechanism 3 is integrally provided in the upper part of the casing 2. In this infrared projection mechanism 3, infrared IR emitted by the infrared semiconductor laser 21 (λ = 780 nm, output 20 mW) is shaped into parallel light by the collimator lens 22 and is incident on the polygon mirror 23. The polygon mirror 23 has five reflecting surfaces on its peripheral surface, and the polygon mirror 23 itself is rotated at 12000 rpm. Therefore, when the polygon mirror 23 rotates, the direction of the infrared light IR that is incident on the polygon mirror 23 and reflected by each reflecting surface follows the rotation direction of the polygon mirror 23 as the reflecting surface rotates. Will be changed. Since the infrared IR reflected by the polygon mirror 23 is projected on the screen S by the projection lens 24 while being linearly scanned, the infrared IR is linearly reflected on the original image projected on the screen S by the projector 1. It will be superimposed on the shape. Here, the projection lens 23 of the infrared projection mechanism 3 is arranged alongside the front surface of the casing 2 together with the projection lens 19 constituting the projector 1, and the optical axes of both projection lenses 19 and 24 are in the same direction. It is set for

  According to the projector 1 having the above configuration, the infrared projection mechanism 3 is driven simultaneously with the projection of a desired image on the screen S. Since the infrared projection mechanism 3 scans the infrared rays emitted from the infrared semiconductor laser 21 by the polygon mirror 23 and projects it on the screen S by the projection lens 24 as described above, a desired projection image projected on the screen S. Infrared IR is superimposed on V on a straight line. Here, visible light is used for the projection image V projected by the projector 1, and the visible light is light having a wavelength of 400 nm to 800 nm, which means light that can be recognized by human eyes. . Infrared rays represent light having a longer wavelength than visible light and cannot be recognized by the human eye. For this reason, even when a human observes a projected image projected on the screen, the infrared rays superimposed on the image are not recognized, so that there is no problem in observing the image.

  On the other hand, when the image V projected on the screen S is voyeurized by a CCD camera or the like, the spectral sensitivity of a typical CCD image sensor is sensitive to the infrared region in both color and black and white CCD elements. As a result, the infrared ray IR superimposed on the image is picked up simultaneously. Here, the optical axis direction of the infrared IR projected on the screen changes with time, and it is scanned not only at one point on the image V projected on the screen S but also in a linear shape. Infrared IR will be imaged over a wide range of images. Therefore, when the voyeur image V is displayed, white or red lines corresponding to infrared rays are displayed in the captured image, and it is immediately determined that the displayed image is a voyeur image. As a result, it is possible to prevent a voyeurized image from circulating as a product and protect the copyright.

  In the infrared projection mechanism 3 according to the first embodiment, when the polygon mirror 23 is rotationally driven at the above-described rotational speed, the period at which the reflection surface of the polygon mirror 23 is switched is 1 millisecond, and the infrared IR is in the display area of the image V. Since most of the images are scanned, even if a photo is taken with a high-speed shutter of 1/1000 second, a trace of infrared IR always remains on the image taken, and the copyright can be protected.

  FIG. 3A is a diagram illustrating a specific example of the relationship between the projection image V and the infrared IR by the projection display apparatus and the projector 1 according to the first embodiment. The projected image V is projected on the screen S, and since this projected image V is visible light, a human can recognize it. On the projected image V, the locus of the infrared IR is superimposed from the upper left to the lower right toward the screen. As described above, by infrared scanning with the polygon mirror 23, the locus of the infrared IR starts from the upper left corner of the screen, continuously moves from the starting point to the lower right direction, and returns to the starting point when the lower right endpoint is reached. Repeat the same operation toward the lower right. The infrared IR trajectory superimposed on the projected image V is not recognized by humans (in the figure, it is described so that it can be recognized for explanation).

  When this projected image V is photographed by a digital video camera equipped with a CCD image sensor, an image in which a wide infrared locus IR 'is superimposed on the image V as shown in FIG. This is because the sensitivity spectral characteristic of the CCD image pickup device of the digital video camera is in the infrared region, so that infrared rays that cannot be recognized by humans are also detected. Further, it is characteristic that the projected image V is more difficult to recognize because the infrared locus IR 'is photographed with a larger thickness (in a wider area). That is, it can be seen that it has a stronger copyright protection effect against copyright infringement acts such as unauthorized shooting of projected images. The reason why the infrared ray trajectory is thicker is that high-intensity infrared rays are superimposed on the main image using an infrared semiconductor laser as an infrared light source, so that the CCD image sensor of the digital video camera is saturated and blooming occurs. .

  FIG. 4A is a diagram showing a relationship between different examples of a projected image and infrared rays. The projected image V is projected on the screen S, and since this projected image V is visible light, a human can recognize it. An infrared spot IRP is superimposed on the projected image. This infrared spot IRP is stationary, but this causes the polygon mirror 23 of the infrared projection mechanism 3 to stop at a predetermined rotational angle position so that infrared radiation from the infrared semiconductor laser 21 enters the stationary polygon mirror 23. This is a result of projecting the reflected light on the screen S. The infrared spot IRP superimposed on the projected image V is not recognized by humans, but when taken with a digital video camera, the infrared spot IRP ′ with a tail up and down as shown in FIG. An image superimposed on the image is obtained. The reason why the infrared spot is tailed up and down is that a smear phenomenon occurs in the CCD image pickup device of the digital video camera because an infrared semiconductor laser is used as an infrared light source and high-intensity infrared light is superimposed on the main image.

  Such blooming phenomenon and smear phenomenon are likely to occur when there is a high-luminance point light source (for example, the sun) on the subject. If an infrared semiconductor laser is used as an infrared light source by utilizing this, high-intensity infrared light can be obtained, so that there is an advantage that a blooming phenomenon and a smear phenomenon are easily caused intentionally. Incidentally, when the brightness of the infrared rays projected by the infrared projection mechanism is low, there is a high possibility that infrared rays will be removed if voyeurism is performed using an infrared cut filter. However, as in the above embodiment, an infrared semiconductor is used as an infrared light source. When using a laser, the locus of infrared rays from the light source is so bright that blooming or smearing occurs, and furthermore, infrared rays having a wavelength close to visible light (for example, λ = 760 nm) can be easily selected. It becomes difficult to be affected by the infrared cut filter, and the effect of copyright protection by voyeurism can be enhanced.

  An infrared LED may be used instead of the infrared semiconductor laser. In this case, since the brightness is lower than that of the infrared semiconductor laser, the copyright protection function may be inferior. On the other hand, since the light from the LED is a diffused light, there is an advantage that it is superior to the laser. is there. If an advanced copyright protection function is required, an infrared semiconductor laser may be selected as the light source, and if not, an infrared LED may be selected as the light source.

  In addition, since the infrared projection mechanism is configured integrally with the projector in this way, the portable device for transporting, managing, handling, and the like of the device can be used as compared with the case where the infrared projection mechanism is configured as a separate device from the projector. Improved. At the same time, the optical axes of both the projection lens of the infrared projection mechanism and the projector can be made coincident with each other, so that infrared rays can be reliably and easily superimposed on the image projected on the screen. In particular, since the optical axis direction of the infrared ray irradiated from the infrared projection mechanism 3 is adjusted once, the subsequent readjustment becomes almost unnecessary, so that the infrared optical axis can be changed even if the installation location of the projector or the row of the projection direction is changed. Re-adjustment is no longer necessary, making it easy to use. Even if the optical axes of both projection lenses are deviated from each other, they do not deviate greatly, and the purpose of superimposing infrared rays on an image can be reliably achieved. Furthermore, infrared is configured as a dedicated projection mechanism and is not shared with the projector's light source, so that the internal temperature of the projector does not increase and it is possible to extend the service life and increase the reliability. Become.

  Infrared semiconductor lasers can be operated in either continuous oscillation or discontinuous oscillation mode. However, in general, a discontinuous oscillation mode infrared semiconductor laser has a higher output. Is more effective.

  In the first embodiment, the configuration example in which the projector and the infrared projection mechanism are integrally assembled in one casing is shown. However, as in the second embodiment shown in FIG. 5, the infrared projection mechanism 3 is replaced with another casing. After being assembled into 2A, the casing 2A may be configured to be integrally fixed to the casing 2 of the projector 1. In such a case, the projection lens of the infrared projection mechanism can be installed on the upper side of the projector projection lens or at any position on the left and right, and the infrared superposition position and direction for the projected image can be set arbitrarily. It is effective in doing.

  In the first and second embodiments, an example in which the present invention is applied to a projector using a projection lens is shown. However, in a projector using a projection mirror, similarly, a projection lens of an infrared projection mechanism is arranged around the projection mirror. Can be configured in the state. Even with this configuration, it is possible to easily and reliably set the infrared projection direction for the projected image.

  Furthermore, although the polygon mirror is used for the infrared projection mechanism in the first embodiment, the same effect can be obtained even if a galvano mirror is used instead of the polygon mirror 9. Further, by using a polygon mirror and a galvanometer mirror together, it is possible to scan the projected image with infrared rays in a two-dimensional direction, which is further effective in enhancing the copyright protection effect by infrared rays.

1 is a schematic perspective view of a projection display device of the present invention. It is a typical perspective view which shows the internal structure of the projection type display apparatus of FIG. It is the figure which showed the image obtained when the relationship between the projection image by the projection type display apparatus of this invention and the scanned infrared rays, and the projected image was image | photographed. It is the figure which showed the image obtained when the projection image by the projection type display apparatus of this invention and the relationship of a spot-like infrared rays, and the image projected are image | photographed. It is a front view of the projection type display apparatus of the other Example of this invention.

Explanation of symbols

1. Projection display device (projector)
2,2A Casing 3 Infrared projection mechanism 11 Light source 12 Reflector 13 Condenser lens 14 Integrator rod 15 Color wheel 16 Condenser lens 17 Total reflection prism 18 DMD panel 19 Projection lens 21 Infrared semiconductor laser 22 Collimator lens 23 Polygon mirror 24 Projection lens IR infrared (trajectory)
IR 'Wide infrared (trajectory)
IRP Infrared spot IRP 'Infrared spot with tails up and down S Screen V Projected image

Claims (8)

  A projection display apparatus for projecting an image on a screen, comprising an infrared projection mechanism for projecting an infrared ray superimposed on the projection image projected on the screen.   The projection display apparatus according to claim 1, wherein the infrared projection mechanism is disposed around a projection lens that projects the image of the projection display apparatus.   The projection display device according to claim 1, wherein the infrared projection mechanism is disposed around a projection mirror that projects the image of the projection display device.   4. The projection display device according to claim 1, wherein an infrared semiconductor laser is used as a light source of the infrared projection mechanism.   4. The projection display device according to claim 1, wherein an infrared LED is used as a light source of the infrared projection mechanism.   The projection display device according to claim 1, wherein the infrared projection mechanism includes a scanning mechanism for scanning the infrared light on the image.   The projection display device according to claim 1, wherein the infrared light is continuous light.   The projection display device according to claim 1, wherein the infrared light is discontinuous light.

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