Optics: image projectors – Composite projected image – Multicolor picture
Reexamination Certificate
2000-10-10
2003-02-18
Dowling, William (Department: 2851)
Optics: image projectors
Composite projected image
Multicolor picture
C348S743000, C359S892000
Reexamination Certificate
active
06520644
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a picture projector, and more particularly to a cylinder-type color wheel adaptive for providing a picture projector with a thin thickness and a fabrication method thereof. Also, the present invention is directed to a picture projector using the same.
2. Description of the Related Art
Generally, a picture projector is a device that enlarges and projects a minute picture implemented internally to display it on a large-dimension screen. In order to realize a color, the interior of such a picture projector is provided with a color wheel for separating red (R), green (G) and blue (B) colors on a time basis. The color wheel is rotated by a rotation of a motor to separate a color sequentially.
FIG.
1
A and
FIG. 1B
show a conventional color wheel. Referring to
FIGS. 1A and 1B
, the conventional color wheel
10
includes a color filter
6
for transmitting only a light beam with a wavelength corresponding to each color in a white light beam, a coupler
4
to which the color filter
6
is attached, and a motor
2
to which the coupler
4
is attached. The color filter
6
consists of a red color filter
6
R for transmitting only a light beam corresponding to a red color in a white light beam, a green color filter
6
G for transmitting only a light beam corresponding to a green color in a white light beam, and a blue color filter
6
B for transmitting only a light beam corresponding to a blue color in a white light beam. The color filter
6
is attached to the coupler
4
by an adhesive, and the coupler
4
is attached to the motor
2
by way of holes
5
provided at the inner side thereof. In other words, the color filter
6
is rotated by a driving force of the motor
2
to sequentially separate a color.
FIG. 2
shows a conventional picture projector in which the color wheel is installed at the interior thereof. Referring to
FIG. 2
, the conventional picture projector includes a lamp
12
for generating a light beam, a reflector
14
for reflecting a light beam into the front direction of the lamp
12
, a first illuminating lens
16
for narrowing a width of a light beam reflected from the reflector
14
, a color wheel
10
for transmitting only a specific color light of a light beam, a field diaphragm
22
for shutting off a spurious light beam in a light beam passing through the color wheel
10
, second and third illuminating lenses
18
and
20
for narrowing a width of a divergent light beam passing through the field diaphragm
22
, a full-reflective mirror
26
for reflecting a light beam passing through the second and third illuminating lenses
18
and
20
in a specific direction, a fourth illuminating lens
28
for converging a light beam reflected from the full-reflective mirror
26
to apply it to a reflective picture display device
30
, a reflective picture display device
30
for reflecting a light beam from the fourth illuminating lens
28
in accordance with an image signal to realize a picture beam, and a projecting lens
32
for enlarging and projecting the picture beam realized at the reflective picture display device
30
at a certain distance. A light beam generated from the lamp
12
is focused to the color filter
6
of the color wheel
10
by means of the reflector
14
. The first illuminating lens
16
narrows a width of the light beam so that all the light beam focused to the color filter
6
by the reflector
14
can pass through the color filter
6
. The color filter
6
is rotated by a driving force of the motor to sequentially transmit red (R), green (G) and blue (B) color lights. A light beam departing a desired light width in light beams passing through the color filter
6
is eliminated by the field diaphragm
22
. The light beam passing through the field diaphragm
22
diverges beyond a focus length of the first illuminating lens
16
. The second and third illuminating lenses
18
and
20
narrow a width of the light beam so that all the light beam diverging beyond a focus length of the first illuminating lens
16
can be incident to the full-reflective mirror
26
. The full-reflective mirror
26
reflects a light beam incident to itself to apply it the fourth illuminating lens
28
. The fourth illuminating lens
28
converges a light beam from the full-reflective mirror
26
into the reflective picture display device
30
. The reflective picture display device
30
reflects a light beam inputted from the fourth illuminating lens
28
in accordance with an image signal to generate a picture beam carried with a picture information and transfers the picture beam to the projecting lens
32
. The projecting lens
32
enlarges the picture beam to transmit the enlarged picture beam onto a screen installed ahead certain distance.
However, the conventional picture projector having the configuration as mentioned above has a problem in that, since only the first illuminating lens
16
is used to input a light beam to the field diaphragm
22
, a light beam is converged into the center thereof to have a non-uniform light distribution caused by an increase in a light amount, thereby deteriorating a brightness uniformity of a picture. In order to solve this problem, a picture projector as shown in
FIG. 3
has been used.
Referring to
FIG. 3
, the conventional picture projector includes a lamp
40
for generating a light beam, a reflector
42
for reflecting a light beam into the front direction of the lamp
40
, a color wheel
10
for transmitting only a specific color light of the light beam, a road lens
44
for making a uniform light distribution of a light beam passing through the color wheel
10
, a collimator lens
46
for progressing a light beam passing through the road lens
44
in parallel, a beam splitter
48
for transmitting a light beam inputted from the collimator lens
46
and reflecting a light beam inputted from a picture display device
50
, a picture display device
50
for reflecting a light beam from the collimator lens
46
in accordance with an image signal to display a picture, and a projecting lens
52
for enlarging and projecting a picture beam inputted from the picture display device
50
at a certain distance. A light beam generated from the lamp
40
is focused to the color filter
6
of the color wheel
10
by means of the reflector
42
. The color filter
6
is rotated by a driving force of a motor
2
to sequentially transmit red (R), green (G) and blue (B) color lights. The light beam color-separated by the color wheel
10
is incident to the road lens
44
. The road lens
44
uniforms a light beam so that the light beam may be uniformly distributed on a screen. A light beam passing through the road lens
44
is progressed to the picture display device
50
in parallel by means of the collimator lens
46
. At this time, the light beam progressing from the collimator lens
46
into the picture display device
50
transmits the beam splitter
48
. The picture display device
50
reflects a light beam inputted from the collimator lens
46
in accordance with an image signal to generate a picture beam carried with a picture information and transfers the picture beam to the beam splitter
48
. The beam splitter
48
32
reflects the picture beam from the picture display device
50
into the projecting lens
52
. The projecting lens
52
enlarges the picture beam to transmit the enlarged picture beam onto a screen provided ahead certain distance.
In the conventional picture projector as shown in
FIG. 2
or
FIG. 3
, it is desirable that, when a light beam passes through the color wheel
10
, the light beam should pass through a boundary portions of the color filter at a minimum time. In other words, a light beam is shut off when it passes through the boundary portions of the color filter
6
. For instance, assuming that the motor is rotated at a speed of 3600 RPM so as to display a field of 60 times per second, a time when a light beam passes through the boundaries will be calculated. In this case, it is assumed that, as shown in
FIG. 4
, a light beam
LandOfFree
Cylindrical color wheel and fabricating method thereof and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cylindrical color wheel and fabricating method thereof and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cylindrical color wheel and fabricating method thereof and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3176744