Optical: systems and elements – Lens – With support
Reexamination Certificate
2003-08-08
2004-12-07
Epps, Gerogia (Department: 2873)
Optical: systems and elements
Lens
With support
C359S694000, C359S814000
Reexamination Certificate
active
06829108
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a lens moving mechanism for retaining and moving a lens barrel of a liquid crystal projector, and to a liquid crystal projector employing the same.
FIG. 1
is an illustration showing a structural example of a conventional liquid crystal projector. In the drawing, a numeral
1
designates a light source consisting of a lamp such as a metal halide lamp, numerals
2
and
3
designate dichroic mirrors for splitting light, numerals
4
and
5
designate reflection mirrors, numerals
6
,
7
, and
8
designate liquid crystal panels, numerals
9
and
10
designate dichroic mirrors for recombining lights, a numeral
11
designates a light path adjusting mechanism consisting of a pair of liquid crystal prisms
12
A and
12
B, and a numeral
13
designates a projection lens. All of these are arranged inside a projector casing
14
.
The light emitted from the light source
1
is split by dichroic mirrors
2
and
3
into lights of three primary colors, that is, red (R), blue (B), and green (G). Each of the split lights is modulated for its transmittance by the corresponding liquid crystal panel
6
,
7
or
8
according to image information of each color component. The liquid crystal panels
6
,
7
and
8
are located in the corresponding light paths, respectively. The modulated lights are recombined by the dichroic mirrors
9
and
10
.
The recombined light is adjusted for its light path by the light path adjusting mechanism
11
and is then enlarged and projected onto a screen (not shown) through the projection lens
13
.
In the aforementioned conventional liquid crystal projector, the light path adjusting mechanism
11
is arranged just before the projection lens
13
. This arrangement has a problem that the miniaturization is difficult, because the light path adjusting mechanism
11
requires to lengthen the distance from the respective liquid crystal panels
6
,
7
and
8
to the projection lens
13
(for instance, the distance m for the liquid crystal panel
6
in
FIG. 1
) in the liquid crystal projector.
There is another problem. That is, lights having image information pass multiple glass plates constituting the liquid crystal prisms
12
A and
12
B of the light path adjusting mechanism
11
after transmitted through the liquid crystal panels
6
,
7
and
8
and are then projected through the projection lens
13
so that the image is enlarged and displayed on the screen. Due to the multiple glass plates, the image distortion and chromatic aberration distortion in the image projected on the screen are increased, thus making high resolution image display impossible.
In order to solve the problem of difficulty in miniaturization and the problem that it is impossible to display a high resolution image due to increase of image distortion and chromatic aberration distortion in the projected image, for example, Japanese Unexamined Patent Publication No. H6-331953 discloses a liquid crystal projector constructed in such a manner that a lens barrel moving mechanism is provided which can move the lens barrel having the projection lens therein relative to the projector casing in a direction perpendicular to the projector casing, thus eliminating the light path adjusting mechanism which is the factor causing the difficulties in miniaturization, and in high resolution image display due to enhancement of image distortion and chromatic aberration distortion.
By structuring a liquid crystal projector in this manner, the miniaturization can be achieved, and it becomes possible as well to perform the shift- or tilt adjustment of the projected image without generation of image distortion and chromatic aberration distortion in the projected image.
SUMMARY OF THE INVENTION
It is an object of the present invention to further improve the above-described lens barrel moving mechanism of a liquid crystal projector in which the light path adjusting mechanism is eliminated, and to provide a lens moving mechanism which has a simple structure and is capable of achieving a smooth and precise movement of the lens barrel, and a liquid crystal projector employing the lens moving mechanism.
In order to achieve the foregoing object, a first invention of the present application provides a lens moving mechanism comprising: a lens retaining member for retaining a lens barrel which is provided therein with a projection lens for projecting light with the image information; a lens retaining member guiding means for guiding said lens retaining member movably in at least one direction of axis which is perpendicular to the optical axis of said light; a fixed supporting member for supporting said lens retaining member guiding means; and a driving means for applying a driving force to the lens barrel, wherein said lens retaining member guiding means comprises: a track member which is provided with a rolling member running surface extending along the longitudinal direction thereof; a movable member which is incorporated in said track member such that the movable member is movable relative to said track member and is provided with a rolling member running surface corresponding to the rolling member running surface of said track member; and a plurality of rolling members arranged between the rolling member running surface of said track member and the rolling member running surface of said movable member.
Since the lens retaining member guiding means has the aforementioned structure, that is, comprising a track member which is provided with a rolling member running surface extending along the longitudinal direction thereof, a movable member which is incorporated in the track member such that the movable member is movable relative to the track member and is provided with a rolling member running surface corresponding to the rolling member running surface of the track member, and a plurality of rolling members arranged between the rolling member running surface of the track member and the rolling member running surface of the movable member, the relative movement of the movable member to the track member is smooth because of the rolling members, thus achieving the smooth movement of the projection lens.
A second invention of the present application provides the aforementioned lens moving mechanism being characterized by further comprising an intermediate member for interconnecting said lens retaining member and said fixed supporting member, wherein said lens retaining member guiding means comprises a first guiding means arranged between said fixed supporting member and said intermediate member and a second guiding means arranged between said intermediate member and the lens retaining member, said first guiding means guides said intermediate member in a first predetermined direction, and said second guiding means guides said lens retaining member in a second predetermined direction perpendicular to said first predetermined direction, and the respective track members and the respective movable members of said first guiding means and said second guiding means are arranged at substantially the same position relative to the direction of the optical axis.
Since the respective track members and the respective movable members of the first guiding means and the second guiding means are arranged at substantially the same position relative to the direction of the optical axis as described above, the lens moving mechanism can be structured to have reduced thickness in the direction of the optical axis, thus enabling a miniaturization.
A third invention of the present application provides the aforementioned lens moving mechanism being characterized in that the track members and the movable members of the lens retaining member guiding means are arranged in such a manner that their transverse directions are substantially parallel to the direction of the optical axis.
Since the track members and the movable members of the lens retaining member guiding means are arranged in such a manner that their transverse directions are substantially parallel to the direction of the optical axi
Eto Kentaro
Hoshide Kaoru
Koba Hiroki
Kouchi Minoru
Takehara Susumu
Epps Gerogia
Hasan M.
Sanyo Electric Co,. Ltd.
Westerman Hattori Daniels & Adrian LLP
LandOfFree
Lens moving mechanism and liquid crystal projector does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Lens moving mechanism and liquid crystal projector, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lens moving mechanism and liquid crystal projector will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3300480