Optics: image projectors – Image moves on screen – Reflector between lamp and screen
Reexamination Certificate
2000-06-30
2002-12-31
Dowling, William (Department: 2851)
Optics: image projectors
Image moves on screen
Reflector between lamp and screen
C353S098000
Reexamination Certificate
active
06499846
ABSTRACT:
BACKGROUND OF THE INVENTION
a) Field of the Invention
This application was published under PCT Article 21(2) in the German language with an English abstract: this is a request for a CPA application under 37 C.F.R. 1.53(d) (continued prosecution application) of pending prior application 09/582,814 filed Nov. 4, 1999 as PCT/EP99/08445 claiming foreign priority to DE 198 51 000.4 filed Nov. 5, 1998 to which priority is hereby claimed. The invention is directed to an arrangement with a projector and a deflecting mirror in which the image projection proceeding from a projection direction impinges on the deflecting mirror which is mounted so as to be movable in two spatial directions and whose mirror surface deflects the projection beams at an elevation angle and an azimuth angle. A projection arrangement of this type can also be called a drawing projector, since a static or moving image is generated, projected onto a projection surface, and moved on the latter.
b) Description of the Related Art
For front projection, the projection surface is a wall (e.g., projection screen) or, in the case of rear projection, a screen (e.g., ground glass screen). The projector is not limited to a certain type of image generation. Projectors which write the image by means of a brightness-modulated and/or color-modulated light beam can be used. These projectors are also known as laser projectors. However, image-forming projectors which generate an image proceeding from an object plane internal to the device as is known, for example, in CRT, LCD, DMD or slide projectors can also be used.
A deflecting device for an image generated by a laser beam is known from U.S. Pat. No. 5,365,288 DEWALD. The image is rotatable by itself by means of a K-mirror arrangement and is then deflected in such a way by a mirror mounted on two axes that the generated image can be deflected in a defined spatial area. The arrangement of the elements for the image deflection is carried out in such a way that the image is generated in a device standing on the floor and is directed to the deflecting mirror proceeding from this floor position.
In relation to a horizontal plane through the axis of rotation of the deflecting mirror, the practical useful deflection angle area resulting from this arrangement
is limited toward the floor due to the required device dimensions and can be, at most, approximately 45° without substantial image shadowing, and
can be at most 30° in practice toward the zenith due to the mirror dimensions increasing toward infinity.
Therefore, the observer is only afforded limited viewing possibilities which are more sharply limited in the direction of the zenith than in the direction of the floor. However, this conflicts with the customary mode of observing images that are generally projected “skyward”, another reason for this being to prevent shadowing caused by other observers or by structural parts. It is impossible to generate images in the vicinity of the zenith with this arrangement.
OBJECT AND SUMMARY OF THE INVENTION
It is the primary object of the invention to increase the area of possible image presentation on a given projection surface in an arrangement of the type mentioned above. The area in which a comparatively small image can be presented within a projection surface which is large in proportion to the image size, especially in a projection dome, is to be expanded. The position of the display area should correspond to the normal viewing habits of the observer and it should also be possible to display an image in the vicinity of the zenith and in the zenith. In this respect, a high-quality monochromatic, black-and-white, or color image can be displayed at relatively little expense and, at the same time, can be moved on the projection surface, in particular, fast enough so that the observer can substantially follow the movement of the image. Further, an arrangement of a plurality of projectors is possible, wherein mutual shadowing is also minimized in this case and the area in which it is possible to display images is maximized for all projectors.
According to the invention, a projection arrangement with a projector and a deflecting mirror are suggested, wherein the image projection, proceeding from a projection direction along a principal projection axis, impinges on the deflecting mirror which is supported so as to be movable in two spatial direction and whose mirror surface deflects a projected light bundle at an elevation angle and at an azimuth angle onto a projection surface standing on the ground, wherein the image projection is effected from the direction of a zenith at an angle &bgr; which is less than 60° in relation to a vertical line from the zenith, and the deflecting mirror is arranged on the ground, wherein, further, the projected light bundle can be deflected toward the projection surface and an image can therefore be generated on the projection surface and moved on the latter.
By “zenith” is meant the zenith of the dome of the sky or the zenith of an artificial dome, e.g., in a planetarium. When it is stated that the deflecting mirror is arranged on the ground, this does not mean that it must lie directly on the ground. It can be arranged far above the surface of the ground by means of a holder or can be fastened to a wall above the surface of the ground or can also be suspended from a ceiling. However, it is essential that the projection is carried out proceeding from the direction of the zenith onto the mirror surface of the deflecting mirror. The indicated quantity of angle &bgr; signifies that the direction of the light bundle impinging on the deflecting mirror comes from the direction of the zenith. By means of the arrangement according to the invention, a surface region that is substantially larger compared to the prior art is achieved, for example, in a projection dome of a planetarium, when an image is displayed, and the image display on the projection surface is not disturbed by shadowing.
Further, the shadowing caused by projectors, other installed items or observers can be minimized. In particular, the display of the image reaches the surface region around the zenith without restrictions and without shadowing.
In an advantageous development of the invention, an image is generated by the projected light bundle only in a partial region of the projection surface and is then movable within the entire area of this projection surface. The movement can be carried out comparatively quickly because the relatively massive projector is stationary and only the comparatively small mass of the deflecting mirror must be moved.
The image should not fill up the entire projection surface statically as is the case, for example, in a cinema, but, rather, should be movable within the display area on the projection surface. The image can be equal to or greater than the projection surface for some applications. In this case, portions of the image cannot be displayed during the movement of the image. For many applications, however, it is sufficient when the size of the moving image is less than 90% in relation to the size of the projection surface. This is advantageous, for example, for image tracking for displaying set designs in entertainment applications when images are to be projected on backdrop arrangements. In this case, the image contents can always be displayed in their entirety. In many applications, the image is a comparatively small image, for example, of a planet or aircraft, that is moved on the projection surface, e.g., over the dome of the sky. However, the size of the image to be displayed by the projector can also be less than 1% of the projection surface.
The image size can be continually adjusted through the realization of a zoom function, so that, for example, an approaching or receding vehicle can be simulated in a realistic manner. This zoom function can be realized by means of known zoom optics or in an image-generating computer.
The control of the deflecting mirror can advantageously be carried out relatively simply when the axis of rotation for adjusting the elevation
Buerdorff Roland
Hiller Klaus
Kuhlmann Werner
Dowling William
LTD GmbH & Co. Laser-Display-Technologie KG
Reed Smith LLP
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