Illumination – Housing
Reexamination Certificate
2003-01-15
2004-10-05
Tso, Laura K. (Department: 2875)
Illumination
Housing
C362S368000, C362S306000, C362S350000, C362S396000
Reexamination Certificate
active
06799871
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lamp mounting structure. More particularly to a lamp mounting structure capable of aligning the optical axis of a lamp correctly while preventing a lamp from being damaged even when it is overheated. Thereby, the invention enhances the stability in the operation of the lamp and improve convenience in association with the use of the lamp. In particular, the present invention can be effectively employed to the cases in which the alignment of the optical axis of a lamp is important, such as the lamp mounting structures of projectors.
2. Background of the Related Art
Generally, a display device using a projection system includes a projector for projecting the light retaining an image signal, and a screen for reflecting the light projected from the projector, thereby displaying an image. The projector mainly includes a lamp for performing a light emitting function, a plurality of dichroic mirrors for reflecting or transmitting the light (white light) emitted from the lamp selectively, a liquid crystal panel for receiving the light beams separated from the light by the dichroic mirrors, thereby forming an image while controlling the amount of the light incident on each pixel thereof, and projection lens for projecting the image formed by the liquid crystal panel while enlarging the image.
The lamp is an essential component of the projector since it determines the basic performance of the projector such as controlling the brightness and color of the image projected onto the screen.
FIGS. 1 and 2
illustrate an embodiment of a conventional lamp. Referring to
FIGS. 1 and 2
, the lamp
10
includes a funnel
12
serving as a mirror, a frame
14
attached to the front end of the funnel
12
, an iron core
16
arranged at the rear portion of the funnel
12
, a neck
18
adapted to partially surround the iron core
16
, and a connecting bolt
19
protruded from the iron core
16
. Metal material such as iron could be used to make the iron core
16
. The iron core
16
is mounted on the neck
18
by a gypsum material interposed therebetween.
The brightness and the color of the image displayed by the projector vary greatly, depending on the direction of the light emitted from the lamp
10
. Accordingly, it is necessary to firmly maintain the mounted state of the lamp
10
. To this end, the lamp
10
is firmly and accurately mounted by a lamp holder
20
in order to prevent the optical axis of the lamp
10
from being miss-aligned in lateral, vertical and logitudina directions, the directions of X, Y, and Z axis in
FIG. 1
, respectively.
The lamp holder
20
, which serves as a mounting structure of the lamp
10
, has a bottom plate
201
, a front plate
202
, and a pair of side plates
203
. The guide plates
22
are placed at both sides of the front plate
202
to fasten the right and the left sides of the frame
14
to the lamp holder
20
. Vertically-extending guide plates
22
are provided at both sides of the rear surface of the front plate
202
. The guide plates
22
serves to the frame
14
of the lamp
10
, thereby holding the lamp
10
in the longitudinal, z-axid, and lateral, x-axis, directions. The lamp holder
20
also has a strip-shaped holding plate
30
mounted between the side plates
203
to hold the lamp
10
in the vertical, y-axis, direction. Both ends of the holding plate
30
are fitted in slots
203
, which are formed at the side plates
203
, respectively.
In the conventional lamp mounting structure having the above mentioned configuration, movements of the lamp
10
in lateral, x-axis directions are restricted by the guide plates of the lamp holder
20
, and movements of the lamp
10
in vertical, y-axis, directions are restricted by the holding plate
30
. Also, movements of the lamp
10
in longitudinal, z-axis, directions are restricted by the front plate
202
of the lamp holder
20
and stoppers that are provided at the lower end of the guide plates
22
. Thus, the movements of the lamp
10
are restricted to prevent the optical axis of the lamp
10
from miss-alignments in any direction.
Meanwhile, heat generated as a result of a high temperature, for example, about 300° C. or above, at the lamp
10
isdue to the operations of the lamp
10
. This heat serves to over-heat the lamp
10
, thereby causing the funnel
12
and the frame
14
to expand. When the funnel
12
and frame
14
expand, an excessive pressure is applied to the funnel
12
by the lamp holder
20
. Since the lamp
10
is placed in between the guide plates
22
of the lamp holder
20
, the expansion may result in a crack, either at the funnel
12
or the neck
18
.
If the width L
2
, the defined space between the guide plates
22
, increases in order to prevent the lamp
10
from being damaged due to a thermal expansion as described above, then the lamp
10
may move laterally resulting in a miss-alignment of the optical axis a normal state. Also, there may be a degraded uniformity of the image displayed on the screen. In particular, the miss-alignment of the optical axis causes the displayed image on the screen to undesirably exhibit undersirable excessive yellow color at the periphery thereof.
SUMMARY OF THE INVENTION
Therefore, the present invention has been made in view of the above mentioned problems. An object of the invention is to provide a lamp mounting structure for a projector which is capable of maintaining a desired alignment of the optical axis of a lamp included in the projector while allowing the lamp to move freely to an certian extent. Thereby the invention will be able to prevent the lamp from being cracked due to an expansion caused by an excessive heat, thus achieving an improved stability in the operation of the lamp.
In accordance with the present invention, the object is accomplished by providing a mounting structure for a lamp comprising: a lamp having a funnel, a frame attached to a front end of the funnel, and a connecting bolt provided at a rear portion of the funnel; a lamp holder, which is adapted to hold the lamp therein while maintaining a desired lateral gap at each side of the frame of the lamp, has a bottom plate, a front plate and a pair of side plates; and a guide that elastically supports the lamp in position comprises hinges formed at the opposite ends of the guide and mounted on the bottom plate of the lamp holder in a manner that allows the hinges to rotate, an engagement member arranged at an intermediate portion of the guide and placed at an upper end of the front plate of the lamp holder and a contact member that is formed at the opposite sides of the engagement member and comes in contact with the lamp.
The lamp mounting structure according to the present invention allows the lamp to be enlarged and shifted to a certain extent with the structure of the lamp holder. Therefore, this structure prevents either the funnel or the neck of the lamp from being cracked even when the lamp is heated. Accordingly, it is possible to lengthen the life of the product to which the lamp mounting structure is employed. In addition, the lamp mounting structure elastically holds the lamp using the structure of the tension guide. Accordingly, when the optical axis of the lamp is miss-aligned due to a shift of the lamp, this miss-alignment is immediately corrected. Thus, there is an advantage in that an improved stability in the operation of the product, for example, a projector, is achieved.
REFERENCES:
patent: 4385345 (1983-05-01), Freudenreich et al.
patent: 4388679 (1983-06-01), Blaisdell et al.
patent: 4430696 (1984-02-01), Lemcke
patent: 4482942 (1984-11-01), Blaisdell et al.
patent: 5101236 (1992-03-01), Nelson et al.
patent: 5215371 (1993-06-01), Pileski
patent: 6280036 (2001-08-01), Suzuki
patent: 6461025 (2002-10-01), Payne
LG Electronics Inc.
Tso Laura K.
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