Optics: image projectors – Composite projected image – Multicolor picture
Reexamination Certificate
1999-02-26
2001-08-28
Dowling, William (Department: 2851)
Optics: image projectors
Composite projected image
Multicolor picture
C353S122000
Reexamination Certificate
active
06280037
ABSTRACT:
BACKGROUND
The invention relates to aligning images of a projection system, such as a liquid crystal display (LCD) projection system, for example.
Referring to
FIG. 1
, a reflective liquid crystal display (LCD) projection system
5
typically includes an LCD display panel (LCD display panels
22
,
24
and
26
, as examples) for each primary color that is projected onto a screen
10
. In this manner, for a red-green-blue (RGB) color space, the projection system
5
may include an LCD display panel
22
that is associated with the red color band, an LCD display panel
24
that is associated with the green color band and an LCD display panel
26
that is associated with the blue color band. Each of the LCD panels
22
,
24
and
26
modulates light from a light source
30
to form red, green and blue images, respectively, that add together to form a composite color image on the screen
10
. To accomplish this, each LCD display panel
22
,
24
or
26
receives electrical signals that indicate the corresponding modulated beam image to be formed.
More particularly, the projection system
5
may include a beam splitter
14
that directs a substantially collimated white beam
11
of light (provided by the light source
30
) to optics that separate the white beam
11
into red
13
, blue
17
and green
21
beams. In this manner, the white beam
11
may be directed to a red dichroic mirror
18
that reflects the red beam
13
toward the LCD panel
22
that, in turn, modulates the red beam
13
. The blue beam
17
passes through the red dichroic mirror
18
to a blue dichroic mirror
20
that reflects the blue beam
17
toward the LCD display panel
26
for modulation. The green beam
21
passes through the red
18
and blue
20
dichroic mirrors for modulation by the LCD display panel
24
.
For reflective LCD display panels, each LCD display panel
22
,
26
and
24
modulates the incident beams, and reflects the modulated beams
15
,
19
and
23
, respectively, so that the modulated beams
15
,
19
and
23
return along the paths described above to the beam splitter
14
. The beam splitter
14
, in turn, directs the modulated beams
15
,
19
and
23
through projection optics, such as a lens
12
, to form modulated beam images that ideally overlap and combine to form the composite image on the screen
10
.
However, for purposes of forming a correct composite image on the screen
10
, the corresponding pixels of the modulated beam images may need to align with each other. For example, a pixel of the composite image at location (0,0) may be formed from the superposition of a pixel at location (0,0) of the modulated red beam image, a pixel at location (0,0) of the modulated green beam image and a pixel at location (0,0) of the modulated blue beam image. Without this alignment, the color of the pixel at location (0,0) may be incorrect, or the color may vary across the pixel.
At the time of manufacture of the system
5
, the LCD display panels
22
,
24
and
26
typically are mounted with sufficient accuracy to align the pixels of the modulated beam images. One way to accomplish this is to approximate the correct position of the LCD display panels
22
,
24
and
26
and thereafter use the LCD display panels
22
,
24
and
26
to attempt to form a white rectangular composite image onto the screen
10
. If the LCD panels
22
,
24
and
26
are not properly aligned, then red
42
, green
44
and/or blue
46
color borders may be detected around the perimeter of a white image
40
that is formed on the screen
10
, as depicted in FIG.
2
. However, when the LCD panels
22
,
24
and
26
are properly aligned, the color borders
42
,
44
and
46
do not appear, and an enlarged white image
40
appears on the screen
10
, as depicted in FIG.
3
.
Unfortunately, conventional techniques that are used to align the LCD display panels
22
,
24
and
26
may consume a considerable amount of time in the manufacture of the projection system
5
. Furthermore, such factors as aging and thermal drift may cause the LCD displays panels
22
,
24
and
26
to fall out of alignment during the lifetime of the projection system
5
.
Thus, there is a continuing need to address one or more of the problems stated above.
SUMMARY
In one embodiment, a projection system includes display panels, optics and an adjustment device. Each display panel is adapted to modulate a different beam of light to form an associated modulated beam of light. The optics are adapted to form an associated image of each modulated beam of light, and the adjustment device is adapted to position one of the display panels to adjust convergence of the images.
In another embodiment, a method includes modulating beams of light with display panels to form modulated beams of light. The modulated beams of light are optically directed to form images. The modulation is regulated to at least partially reduce portion of the images that do not overlap.
REFERENCES:
patent: 5092671 (1992-03-01), Van Os
patent: 5200815 (1993-04-01), Tsujihara et al.
patent: 5283599 (1994-02-01), Tejima et al.
patent: 5475447 (1995-12-01), Funado
patent: 5483299 (1996-01-01), Minoura
patent: 5624174 (1997-04-01), Loucks
patent: 5653522 (1997-08-01), Loucks
patent: 5868485 (1999-02-01), Fujimori et al.
patent: 5978054 (1999-11-01), Fujimori
patent: 6056407 (2000-05-01), Iinuma et al.
patent: 0 734 184 A (1996-09-01), None
patent: 05 281512 (1993-10-01), None
patent: 05 273513 (1993-10-01), None
Patent Abstract of Japan, vol. 018, No. 067 (Feb. 3, 1994).
Patent Abstracts of Japan, vol. 018, No. 048 (Jan. 25, 1994).
Dowling William
Intel Corporation
Trop Pruner & Hu P.C.
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