Note: Descriptions are shown in the official language in which they were submitted.
CA 02227920 1998-01-27
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1 . M~lnO~ AND DEVICE FOR ELIMINATING EDGES OF TWO PROJECTION PICTURES
2 R~C~GROUND OF THE lNV~r.llON
3 1. Field of the Invention
4 The present invention relates to a device and a method
for eliminating overlappe~ edges of two adjacent projection
6 pictures and, more particularly, to an improved device and
7 method which includes a comb filter disposed in front of a
8 lens of a projector so as to produce a diffraction feature to
9 adjust light distribution on an area of overlapped edges
between two projection pictures.
11 2. Brief Description of the Prior Art
12 Generally, when a large projection picture or a visual
13 scene is needed to be projected on a screen, for example, 20
14 meters times 20 meters, a plurality of projectors are
required to be arranged at suitable positions so that all the
16 projection pictures from the projectors can assemble a
17 complete scene. These projection pictures are arranged to
18 show on a screen with a specific sequence, that is to say,
19 these projection pictures are arranged side-by-side.
Referring to Figures 1 and 2, three projectors 10, 11, 12,
21 for example, are used to project three respective projection
22 pictures 100, 110, 120 on a screen, wherein each one of the
23 three projectors 10, 11, 12 has three projection lenses 3.
24 There will be two overlapped areas lOa, lOb formed on the
screen. The area lOa is composed of a first boundary portion
26 101 from the projector 10 and a second boundary portion 111
27 from the projector 11, the area lOb is composed of the second
28 boundary portion 111 and a third boundary portion 121.
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1Accordingly, the two areas lOa, lOb will be brighter than that
2on the three projection pictures 100, 110, 120. These areas
3lOa, lOb are shown as two edges defined between any two
4adjacent pictures, and this seriously reduces a quality of
5the whole picture on the screen. Furthermore, the edges could
. 6mis-guide the viewer when used in an imitation machine for
7pilots. A conventional method to eliminate overlapped edges
8on the screen is to dispose at least one "edges reducing
gprocessing device" and adjust circuits of the projectors to
10adjust a brightness of the projection pictures. However, the
11edge reducing processing device uses a complicated circuit
12and many expensive parts so that the device has a high price
13which cannot be afforded by ordinary companies. Besides, such
14a device has a good performance on a plan screen but a curved
15screen. When the picture comprises a bright area such as the
16sky, and a dark area such as the land, the overlapped areas,
17if in t:he sky area, will show a brighter area, and if in the
18land area, will show a darker area. This is conventionally
19adjusted by adjusting a "gamma value" of the device by
20computer. Generally, there have 147,456 choices of the "gamma
21value" to be chosen and this definitely takes very much time.
22The present invention intends to provide an improved
23device and method for eliminating overlapped edges of two
24adjacent projection pictures to mitigate and/or obviate the
25above-mentioned problems.
26SU~AR~ OF THE INVENTION
27In one aspect of the present invention, there is
28provided a device for eliminating overlapped edges of two
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1 adjacent projection pictures, comprising a plurality of plates
2 being adapted to be movably disposed in front of a projection
3 lens, each of the plates having a sharp end which is adapted
4 to be movably disposed relative to a periphery of the lens.
It is an object of the present invention to provide a
6 device which movably disposes a plurality of plates in front
7 of a lens of a projector to produce diffractions around the
8 plates to eliminate overlapped edges of two projection
9 pictures.
It is another object of the present invention to
11 provide a method to eliminate overlapped edges of two
12 projection pictures.
13 Other objects, advantages, and novel features of the
14 invention will become more apparent from the following
detailed description when taken in conjunction with the
16 accompanying drawings.
17 BRIEF DESCRIPTION OF THE DRAWINGS
18 Fig. 1 shows an illustrative view of three
19 convent:ional projectors and a screen on which two overlapped
areas are formed;
21 Fig. 2 shows an illustrative view of three
22 convent:ional projection pictures and the two overlapped areas
23 on the screen as shown in Fig. 1;
24 Fig. 3 is a perspective view of a projector which has
three devices in accordance with the present invention
26 respectively disposed in front of three lenses of the
27 projector;
28 Fig. 4 is an exploded view of the device in accordance
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1with the present invention and the lens;
2Fig. 5 is a fragmentary view to show the plates and
3the rails of the frame;
4Fig. 6 is a front end elevational view to show the
5device of the present invention;
6Fig. 7 is an illustrative view to show the plates are
7adjusted when the projector is operated;
8Fig. 8 shows a flow chart to describe a method of the
9present: invention;
10Fig. 9 shows an illustrative view of three projectors
11each having the device of the present invention and a screen
12on which two overlapped areas are formed, and
13Fig. 10 shows an illustrative view of three projection
14pictures and the two overlapped areas which are eliminated by
15the device of the present invention.
16DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
17Referring to the drawings and initially to Figs. 3
18through 6, a projector 20 generally has three projection
19lenses 30, 31, 32 which respectively control base colors,
20red, green and blue to be projected on a screen 60 as shown
21in Fig. 9. A device in accordance with the present invention
22generally includes a frame 500 which is rectangular and
23fixedly connected to a tube 300 by a connector 501 with
24screws 502. The tube 300 has a lens 301 received therein so
25that light will projected to the screen 60 via the lens 301.
26The frame 500 is disposed in front of the lens 301 and has
27two opposite sides. Each of the two sides has two columns 50
28with a slot 51 defined between the two columns 50, each of
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1 the two columns 50 having a plurality of rails 52 extending
2 from an inner side thereof. A plurality of plates 40 each
3 have a sharp end 42 and two ribs 41 respectively extend from
4 two opposite sides of each of the plates 40 so that the two
ribs 41 are supported ar;d movably disposed between two
- 6 opposite rails 52. Each of the sharp ends 42 of plates 40
7 extend into an area of the lens 301 and are movably disposed
8 relative to a periphery of the lens 301.
g Referring to Fig. 7, when operating the projector 20,
light is emitted through the lens 301 and the light can be
11 supposed to have a central portion H and two boundary
12 portions Hl. Referring to Figs. 9 and 10, an embodiment is
13 taken to describe how the device works, three projectors 20,
14 21 and 22 each have three lenses 30, 31, 32 so that there
will three projection pictures 200, 210 and 220 shown in the
16 screen 60. Two overlapped areas 211, 212 are respectively
17 formed between the three pictures 200, 210 and 220, and each
18 of the overlapped areas 211, 212 are formed by the overlapped
19 boundary portions Hl.
Referring to Figs. 7 and 8, the plates 40 are moved
21 toward the corresponding lens 301 so that a diffraction is
22 occurred around the plates 40. The diffraction reduces
23 brightness of the boundary portions Hl so that the brightness
24 of the overlapped areas 211, 212 can be adjusted thereby.
Therefore, an operator may adjust the plates 40 by pushing
26 them toward the lens 302 or pulling them away from the lens
27 302 till a desired brightness is reached in the overlapped
28 areas 211, 212.
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1 It is experienced that the device in accordance with
2 the present invention does not need highly trained or skilled
3 persons to operate and the cost thereof is much lower than
4 the conventional one. Furthermore, the device is well
performed on a curved scree~n.
6 Although the invention has been explained in relation
7 to its preferred embodiment, it is to be understood that many
8 other possible modifications and variations can be made
9 without departing from the spirit and scope of the invention
as hereinafter claimed.
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