Optics: image projectors – Composite projected image – Multicolor picture
Reexamination Certificate
2003-06-05
2004-06-01
Fuller, Rodney (Department: 2851)
Optics: image projectors
Composite projected image
Multicolor picture
C353S094000, C349S008000, C349S009000
Reexamination Certificate
active
06742898
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a projector device and, in particular, the present invention relates to a projector device equipped with a plurality of light sources.
2. Description of the Prior Art
The projector device using liquid crystal panels is well known. In such projector device, a single, large size lamp is usually used as a light source.
FIG. 9
shows an example of a conventional projector device using liquid crystal panels. As shown in
FIG. 9
, the projector device includes a lamp
101
, a reflection mirror
102
, an integrator
103
, a polarizer portion
104
, a field lens
105
, dichroic mirrors
106
and
107
, liquid crystal panels
108
R,
108
G and
108
B, a cross dichroic prism
109
and a projection lens
110
.
In the conventional projector device shown in
FIG. 9
, light emitted from the lamp
101
, which is a high power, large size lamp, is reflected by the reflection mirror
102
as parallel light fluxes. The parallel light fluxes are incident on the integrator
103
in which luminance of a center portion and of a peripheral portion of the parallel light fluxes is averaged. The averaged light from the integrator
103
is converted into linear polarized light corresponding to transmission characteristics of the liquid crystal panels
108
R,
108
G and
108
B by the polarizer portion
104
and then converted into parallel light fluxes having a predetermined diameter by the field lens
105
.
The parallel light fluxes from the field lens
105
is incident on the dichroic mirror
106
. Only red color light portion thereof is allowed to transmit the dichroic mirror
106
and other color light portions having other colors are reflected thereby. The red color light transmitted through the dichroic mirror
106
passes through the liquid crystal panel
108
R, which transmits red color light corresponding to brightness of portions of an image, resulting in a red color image light.
Further, the other color lights reflected by the dichroic mirror
106
are incident on the dichroic mirror
107
and a green color light portion thereof is reflected thereby and a blue color light transmits therethrough. The green color light reflected by the dichroic mirror
107
passes through the liquid crystal panel
108
G, which transmits a green color light corresponding to brightness of portions of an image, resulting in a green color image light.
The blue color light transmitted through the dichroic mirror
107
passes through the liquid crystal panel
108
B, which transmits a blue color light corresponding to brightness of portions of an image, resulting in a blue color image light.
The red color image light obtained by the liquid crystal panel
108
R, the green color image light obtained by the liquid crystal panel
108
G and the blue color image light obtained by the liquid crystal panel
108
B are synthesized by the cross dichroic prism
109
, resulting in a color image light. The thus produced color image light is enlarged by the projection lens
110
and projected onto a screen
111
.
In the conventional projector device, the single, large lamp is used as the light source as shown in FIG.
9
.
This is because, in order to obtain a high luminance image by the projector device, it is necessary to increase the output power of the light source.
However, when such large lamp is used, a large space is necessary, so that a reduction of size of the projector device is difficult. Further, since an amount of heat generated by the lamp is considerable, special consideration for heat sink is indispensable.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a projector device capable of obtaining high luminance without requiring a large light source.
The projector device according to the present invention includes a plurality of light sources having parallel optical axes offset in a direction perpendicular to the optical axis direction and an optical member for compressing light fluxes emitted from the light sources in the offset direction. The projector device further includes a reflector portion for reflecting the light fluxes from the light sources and directing the reflected light fluxes in one direction. The reflected light fluxes are emitted through a condenser portion as a single light. The single light flux is incident on an image forming portion. In the image forming portion, the single light flux is separated to a plurality of color light fluxes and the color light fluxes pass through spacial modulator elements, which spatially modulate the color light fluxes correspondingly to respective color images to form image lights of respective colors. And then, the color image light fluxes are synthesized to form a color image. The color image formed in the image forming portion is projected onto a screen by a projector portion including a projection lens, etc.
In the above mentioned projector device, the reflector portion includes a pair of flat reflection mirrors or a pair of reflection prisms, which are juxtaposed such that reflecting surfaces of the flat reflection mirrors or the reflection prisms are orthogonal to each other and light fluxes from the light sources are reflected by the reflection surfaces of the reflection mirrors or the reflection prisms at right angles, respectively, to form parallel light fluxes.
When the reflection mirrors are employed, it is preferable that the mirrors are cold mirrors, which reflect visible light while transmitting infra-red light.
As the optical member for compressing light fluxes in the offset direction, a cylindrical lens is preferable.
The condenser portion preferably includes a concave lens for diverging the compressed light fluxes from the reflector portion and a pair of integrators for averaging amounts of lights from center portions and peripheral portions of the light fluxes from the concave lens.
Alternatively, the optical member for compressing light in the offset direction may have a function of averaging amounts of lights from a center portion and a peripheral portion of the light flux from the concave lens as well. In such case, it is preferable that a polarizer portion is provided between the optical member and the reflector portion.
In the above mentioned projector device, each of the light sources is constructed with a lamp and a reflection mirror and the light sources are arranged in an offset relation such that optical axes thereof are parallel to each other. It is practical that the spacial modulator elements are liquid crystal panels, respectively. Extra-high pressure mercury lamps are suitable for the lamps. Further, the projection lens constituting the projector portion preferably has a zooming function.
Particularly, the projector device according to the present invention is featured by that the optical member for compressing the lights in the offset direction is constructed with a cylindrical lens, the reflection member is composed of a pair of reflection mirrors or reflection prisms having reflecting surfaces orthogonal to each other so that the light fluxes from the light sources are reflected at right angles by the reflection surfaces to form parallel light fluxes, the condenser portion unifies polarizing directions of a plurality of incident lights to form a single emitting light including linear-polarized lights coincident with polarizing directions of the liquid crystal panels and the image light forming member decomposes the light emitted from the condenser member to a red, green and blue color lights and produces a color image light by passing the decomposed color lights through the liquid crystal panels and the projection member for projecting the color image light is a projection lens.
In another embodiment of the projector device according to the present invention, the condenser member includes a first and second integrators for unifying the lights from the light sources, compressing the lights in the offset direction and converting them into linear polarized lights coincident with the polarizing directions of said l
Dalakis Michael
Fuller Rodney
NEC Viewtechnology Ltd.
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