Information
-
Patent Grant
-
6384874
-
Patent Number
6,384,874
-
Date Filed
Friday, February 12, 199925 years ago
-
Date Issued
Tuesday, May 7, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Kananen, Esq.; Ronald P.
- Rader, Fishman & Grauer, PLLC
-
CPC
-
US Classifications
Field of Search
US
- 348 744
- 348 748
- 348 749
- 348 776
- 348 777
- 348 779
- 348 805
- 411 542
- 313 35
- 313 45
-
International Classifications
-
Abstract
The present invention provides a display apparatus for discharging and removing needless cooling liquid consistently when the display apparatus for cooling a cathode ray tube with cooling liquid is fabricated and relates to a display apparatus for cooling cathode ray tubes with cooling liquid is provided with a cooling liquid container for containing cooling liquid for cooling the cathode ray tubes, a sealing member for sealing cooling liquid in the cooling liquid container by plugging a cooling liquid charging hole formed on the cooling liquid container after cooling liquid is charged into the cooling liquid container, and a residual cooling liquid discharging outlet provided with connection to the sealing member and the cooling liquid container for discharging residual cooling liquid in the space between the sealing member and cooling liquid container to the outside though the space between the sealing member and the cooling liquid container.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an display apparatus for projecting an image displayed on a cathode ray tube, and more particularly relates to improvement of a display apparatus having a structure for cooling a cathode ray tube with cooling liquid.
2. Description of Related Art
Recently, with popularization of multi-media apparatuses and computers, demand for a display apparatus having a large screen has risen increasingly. Various types of television receivers, image monitors, and image projectors which use a cathode ray tube (CRT) have been proposed as display apparatuses for displaying images of this sort. Among these display apparatuses, a type of display apparatus having structure for enlarging an image displayed on a cathode ray tube and displaying the enlarged image on a screen has been known. A display apparatus of this type can project the light of an image onto the front side of the screen or display an enlarged image on the screen by projecting the light of the image from the back side of the screen.
A projection type display apparatus for forming an image by projection is provided with three cathode ray tubes corresponding to a red (R) image, a green (G) image, and a blue (B) image to be projected on the screen side. These images displayed by these cathode ray tubes are subjected to optical processing through lenses and projected on the screen side. Because the respective cathode ray tubes generate heat, the cathode ray tubes should be cooled with cooling liquid. Cooling liquid used for cooling a cathode ray tube is usually a liquid mixture which is non-volatile under a normal temperature containing mainly, for example, ethylereglycol, and such cooling liquid is apt to stay without evaporation.
FIG. 1
shows a conventional projection type display apparatus. This display apparatus has three cathode ray tubes
1000
,
1001
, and
1002
; the respective cathode ray tubes
1000
,
1001
, and
1002
form images of monochromatic colors namely red (R), green (G), and blue (B), and the respective images are projected on the screen
1004
through lenses
1003
to form a color image on the screen
1004
. Cooling mechanisms
1005
for holding cooling liquid are provided between these cathode ray tubes
1000
,
1001
, and
1002
and corresponding lenses
1003
.
FIG. 2
shows a cathode ray tube
1000
(
1001
, and
1002
) and the cooling mechanism
1005
. The cooling mechanism
1005
has a metal box
1006
, and a metal box
1006
has the structure for containing cooling liquid
1007
in the metal box
1006
. Cooling liquid
1007
is charged from a hole
1008
, and a sealing screw
1009
is tightened after charging so that the cooling liquid
1007
does not leak through the hole
1008
.
FIG.
3
and
FIG. 4
show a screw
1009
tightened in the hole
1008
of the metal box
1006
. An O-ring
1011
for sealing is provided between the screw
1009
and the groove
1010
of the metal box
1006
.
Application of such structure causes problems as described hereafter. In
FIG. 2
, when cooling liquid
1007
is charged into the metal box
1006
though the hole
1008
and thereafter the screw
1009
is screwed into the hole
1008
, as shown in
FIG. 4
, a part
1007
A of the cooling liquid
1007
is confined in a space defined by the groove
1010
, the O-ring
1011
, and the screw
1009
, because cooling liquid remains in the groove
1010
when cooling liquid is charged.
The needless liquid
1007
A confined as described herein above leaks slowly with time to the outside from the space defined by the screw
1009
, the groove
1010
, and the O-ring
1011
. Thus cooling liquid
1007
A leaks though there is no structural defect and fabrication defect. The cooling liquid which leaks to the outside remains on the metal box
1006
because cooling liquid is non-volatile under a normal temperature.
OBJECT AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a display apparatus having a structure for discharging and removing needless cooling liquid consistently when a display apparatus having a structure for cooling a cathode ray tube with cooling liquid is fabricated.
The present invention is accomplished by using a display apparatus having a structure for projecting and displaying an image displayed on a cathode ray tube and having a structure for cooling the cathode ray tube with cooling liquid provided with a cooling liquid container for containing cooling liquid for cooling the cathode ray tube, a sealing member for sealing cooling liquid in the cooling liquid container by plugging a cooling liquid charging hole formed on the cooling liquid container after cooling liquid is charged into the cooling liquid container, and a residual cooling liquid discharge outlet provided with connection to the sealing member and the cooling liquid container for discharging residual cooling liquid in the space between the sealing member and the cooling liquid container to the outside through the space between the sealing member and the cooling liquid container.
In the present invention, the cooling liquid container contains cooling liquid used for cooling a cathode ray tube. The sealing member seals cooling liquid in the cooling liquid container by plugging the cooling liquid charging hole formed on the cooling liquid container after charging of cooling liquid into the cooling liquid container. The residual cooling liquid discharging outlet provided with connection to the sealing member and the cooling liquid container functions to discharge and remove residual cooling liquid remaining in the space between the sealing member and the cooling liquid container to the outside though the space between the sealing member and the cooling liquid container. Thereby, residual cooling liquid remaining in the space between the sealing member and the cooling liquid container is discharged to the outside easily through the cooling liquid discharge outlet, the problem of confined cooling liquid is solved, and liquid leakage is eliminated.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a plan view for illustrating a conventional display apparatus.
FIG. 2
is a side view for illustrating a cathode ray tube and a metal box for containing cooling liquid of a conventional display apparatus of FIG.
1
.
FIG. 3
is a plan view for illustrating a screw attached to the conventional metal box.
FIG. 4
is a cross sectional view along a, line
4
—
4
, in FIG.
3
.
FIG. 5
is a side view of a preferred embodiment of the display apparatus of the present invention.
FIG. 6
is a plan view for illustrating cathode ray tubes, a cooling mechanism, a projection lens, and a screen of the display apparatus of the present invention in FIG.
5
.
FIG. 7
is a side view for illustrating components of the structure shown in FIG.
6
.
FIG. 8
is a side view for illustrating one cathode ray tube and the cooling mechanism.
FIG. 9
is a plan view for illustrating a vicinity of an charging hole and a sealing member shown in FIG.
8
.
FIG. 10
is a cross sectional view along the line
10
—
10
in FIG.
9
.
FIG. 11
is an exploded perspective view for illustrating the structure shown in FIG.
9
and FIG.
10
.
FIG. 12
is a plan view for illustrating the vicinity of a sealing member and a charging hole in another embodiment of the display apparatus of the present invention.
FIG. 13
is a cross sectional view along the line
13
—
13
in FIG.
12
.
FIG. 14
is a perspective view for illustrating the sealing member and O-ring shown in FIG.
13
.
FIG. 15
is a diagram for illustrating another embodiment of the display apparatus of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention will be described in detail with reference to the drawings.
Because the embodiments described hereinafter are detailed examples of the present invention, though the embodiments are described with various technically preferable restrictions, the scope of the present invention is by no means limited to these embodiment unless otherwise specified to limit the present invention in the description hereinafter.
FIGS. 5
to
12
show a preferred embodiment of the present invention. A display apparatus
10
shown in
FIG. 5
is a so-called back projection display apparatus, which projects the projection light
16
of an image to the back side
14
of a screen
12
.
The display apparatus
10
is provided with a cabinet
20
, a signal generation unit
22
disposed in the cabinet
20
, cathode ray tubes (CRT)
30
,
32
, and
34
, a cooling mechanism
40
, and the screen
12
.
The cathode ray tubes
30
,
32
, and
34
are cathode ray tubes of the same type, and the cathode ray tube
30
forms a red (R) image, the cathode ray tube
32
forms a green (G) image, and the cathode ray tube
34
forms a blue (B) image. In other words, these cathode ray tubes
30
,
32
, and
34
form monochromatic images respectively, and form an overlapped color image on the screen
12
.
The cooling mechanism
40
in
FIG. 6
is provided to cool the cathode ray tubes
30
,
32
, and
34
, and disposed between the cathode ray tubes
30
,
32
, and
34
and projection lenses
50
,
52
, and
54
.
The projection lenses
50
,
52
, and
54
shown in
FIG. 6
project the respective color images formed by the cathode ray tubes
30
,
32
, and
34
on an image forming area
12
A on the screen
12
to form a color image.
In
FIG. 6
, the cathode ray tube
32
is disposed in the perpendicular direction to the screen
12
, and the cathode ray tube
30
and the cathode ray tube
34
are disposed with an inclination angle θ respectively. The cathode ray tubes
30
,
32
, and
34
are viewed overlapped in the side view as shown in FIG.
7
and
FIG. 5
, and the cathode ray tubes
30
,
32
, and
34
are viewed separately with an angle θ in the top view as described herein above as shown in FIG.
6
.
FIG. 8
shows the cathode ray tube
30
(
32
and
34
) in FIG.
6
and one example of a cooling mechanism
40
. Because the cathode ray tubes
30
,
32
, and
34
have the same structure, the structure of the cathode ray tube
30
is described as an example. The cathode ray tube
30
has a panel
60
and funnel
62
, and the funnel
62
is provided with an electron gun not shown in the drawing.
Based on a signal supplied from the signal generation unit
22
in
FIG. 5
, the electron gun forms an image on the panel
60
side in the normal manner.
The cooling mechanism
40
is disposed facing to the panel
60
and the side
63
of the funnel
62
. The cooling mechanism
40
is a component for cooling preferably the front face of the cathode ray tube
30
, namely the panel
60
and preferably the side
63
of the side member of the cathode ray tube
30
, namely the funnel
62
. The cooling mechanism
40
has a metal box
42
and a front panel
44
, and has a structure having a sealed space for containing cooling liquid
70
between the metal box
42
and the front panel
44
, and the front panel
44
and the metal box
42
form a cooling liquid container
72
.
For charging cooling liquid into the cooling liquid container
72
, cooling liquid is charged from a charging hole
74
formed on the metal box
42
. A sealing member
76
is inserted into the charging hole
74
to plug the charging hole after cooling liquid
70
is charged in the cooling liquid container
72
so that the cooling liquid
70
in the cooling liquid container
72
does not leak to the outside.
The metal box
42
in
FIG. 8
, the charging hole
74
, the sealing member
76
, and their vicinities are shown enlarged in FIG.
9
and FIG.
10
. On the end
42
A of the metal box
42
, for example, a circular hole
42
B is formed. The size of the hole
42
B is larger than the size of the sealing member
76
. A plurality of grooves
78
are preferably formed between the hole
42
B and the charging hole
74
.
FIG. 11
shows the grooves
78
, the charging hole
74
, the sealing member
76
, and an O-ring
80
.
The grooves
78
comprise four grooves formed, for example, with a 90 degree phase interval, and the grooves
78
are communicated to a circular groove
82
having a size for accepting the head
76
A of the sealing member
76
. In other words, four grooves
78
extend radially from the circular groove namely ring groove
82
, and the grooves
78
and the groove
82
form a residual cooling liquid discharge outlet
90
.
The grooves
78
are disposed along two orthogonal straight lines L
1
and L
2
.
On the inside surface of the charging hole
74
, a female thread
74
A is formed.
The sealing member
76
shown in
FIG. 11
has a head
76
A and a male thread
76
B. On the head
76
A, for example, a tool hole
76
C for accepting a cruciate tool is formed.
The male thread
76
B of the sealing member
76
is screwed into the female thread
74
A of the charging hole
74
with interposition of the O-ring
80
. Thereby, as in
FIG. 10
, the O-ring
78
ensures sealing between the bottom of the head
76
A of the sealing member
76
and the inside bottom
87
of the metal box
42
so that cooling liquid
70
does not leak from the inside of the metal box
42
shown in
FIG. 8
to the outside through the charging hole
74
. The O-ring is preferably made of material which maintains its durability and elasticity in the cooling liquid
70
.
The residual cooling liquid discharge outlet
90
shown in
FIG. 11
is provided to discharge cooling liquid
70
A shown in
FIG. 10
to the outside easily and consistently. In detail, the residual cooling liquid discharge outlet
90
is structured so that needless cooling liquid
70
A which is residual in the space between the bottom of the head
76
A of the sealing member
76
, the inside bottom
87
, and the O-ring
80
is discharged to the outside along the direction of the arrow A shown in FIG.
10
.
Next, cooling liquid charging work into the cooling mechanism
40
of the above-mentioned display apparatus
10
, removing work of needless cooling liquid
70
A, and an exemplary use of the display apparatus
10
shown in
FIG. 5
are described. The cooling mechanism
40
shown in FIG.
5
and
FIG. 8
is disposed on the panel
60
side of the cathode ray tube
30
. Cooling liquid
70
is charged into the cooling liquid container
72
though the charging hole
74
for filling. After the filling, the male thread
76
B of the sealing member
76
is screwed into the female thread
74
A of the charging hole
74
shown in FIG.
10
. In this case, the O-ring
80
is placed between the head
76
A and the inside bottom
87
. Thereby, the sealing member
76
and the O-ring
80
function to prevent cooling liquid
70
in the cooling liquid container
72
shown in
FIG. 8
from leaking through the charging hole
74
.
During the charging work described herein above, needless cooling liquid
70
A remains on the bottom of the head
76
A of the sealing member
76
shown in
FIG. 10
, near the inside bottom
87
, and near the O-ring
80
. In the case that ethyleneglycol is used as the cooling liquid
70
, the needless cooling liquid
70
A is dissolved, for example, in water easily by charging water from the outside. By blowing high pressure air against the mixture of the residual cooling liquid and water, the needless cooling liquid
70
A is blown away with water to the outside along the direction of the arrow A.
As described herein above, by providing the plurality of grooves
78
and the groove
82
of the residual cooling liquid discharge outlet
90
, needless cooling liquid, which is confined in the inside conventionally, is discharged to the outside completely prior to fabrication work. Therefore, cooling liquid will not leak consistently from the product later.
In the fabricated display apparatus shown in
FIG. 5
, the cathode ray tubes
30
,
32
, and
34
project R, G, and B images respectively onto the image forming area
12
A of the screen
12
through the lenses
50
,
52
, and
54
in
FIG. 6
when signal image forming signals are transmitted from the signal forming unit
22
. Thereby, a dynamic or static color image is formed on the screen
12
. In this case, because the panel
60
which is the front side of the cathode ray tubes
30
,
32
, and
34
shown in FIG.
8
and the side vicinity
63
of the funnel
62
are cooled, the operation of the respective cathode ray tubes
30
,
32
, and
34
is stabilized, and also heat is prevented from being enclosed in the cabinet shown in FIG.
5
.
Next, FIG.
12
and
FIG. 13
show another embodiment of the display apparatus of the present invention wherein, particularly FIG.
12
and
FIG. 13
correspond to FIG.
9
and
FIG. 10
of the previous embodiment respectively. The same components shown in FIG.
12
and
FIG. 13
as those shown in FIG.
9
and
FIG. 10
are given the same characters, and the description is omitted.
In the embodiment shown in FIG.
12
and
FIG. 13
, the shape of the residual cooling liquid discharge outlet
190
is different from the residual cooling liquid discharge outlet
90
shown in FIG.
9
and FIG.
10
. In detail, the residual cooling liquid discharge outlet
190
in
FIGS. 12 and 13
has grooves
178
formed on the bottom of the head
176
A of the sealing member
176
. The grooves
178
are components for discharging residual cooling liquid
70
A. The needless residual cooling liquid
70
A in a space defined by the bottom of the head
176
, the O-ring, inside bottom
87
, and side
99
is discharged to the outside in the direction of the arrow A or through the plurality of grooves
178
in the same manner as described hereinbefore.
As shown in FIG.
12
and
FIG. 14
, the grooves
178
are formed radially with a 90 degree interval on the bottom of the head
176
A. The head
176
A has a tool hole
176
C for accepting a cruciate tool.
FIG. 14
shows the sealing member
176
and the O-ring
80
. The sealing member
176
has the head
176
A and a male thread
176
B. The male thread
176
B is screwed into the female thread
74
A of the charging hole
74
shown in FIG.
13
.
The display apparatus
10
shown in
FIG. 5
is a display apparatus of so-called back projection type which projects projection light
16
onto the back side
14
of the screen
12
. On the other hand, the display apparatus shown in
FIG. 15
is a so-called front face projection type display apparatus
110
which projects projection light
16
of an image onto the front face (front side) of the screen
112
. In the display apparatus
110
, the cooling mechanism and the sealing member described hereinbefore in the embodiment of the present invention may be used.
The present invention is by no means limited to the above-mentioned embodiments.
In the above-mentioned embodiments, the case that a color image is obtained using arranged three monochromatic cathode ray tubes is described, the present invention is by no means limited to such case. Alternatively, a cathode ray tube which projects R, G, and B color image light onto a screen from a single cathode ray tube may be used. The cooling mechanism can be applied to such cathode ray tube. The thread type sealing member is employed, but the present invention is by no means limited to the type. Alternatively the type in which a sealing member is fitted with a pressure simply, instead of screwing, may be used to prevent cooling liquid from leaking.
Claims
- 1. A display apparatus for projecting and displaying an image displayed on a cathode ray tube and for cooling said cathode ray tube with cooling liquid comprising:a cooling liquid container for containing cooling liquid for cooling said cathode ray tube; a sealing member for sealing cooling liquid in said cooling liquid container by plugging a cooling liquid charging hole formed on said cooling liquid container after cooling liquid is charged into said cooling liquid container; and a residual cooling liquid discharge outlet provided with connection to said sealing member and said cooling liquid container for discharging residual cooling liquid in a space between said sealing member and said cooling liquid container to the outside through the space between said sealing member and said cooling liquid container.
- 2. A display apparatus as claimed in claim 1, wherein said residual cooling liquid discharge outlet is a groove formed on said cooling liquid container.
- 3. A display apparatus as claimed in claim 1, wherein said residual cooling liquid discharge outlet is a groove formed on said sealing member.
- 4. A display apparatus as claimed in claim 2, wherein said sealing member has a male thread and has a head provided on the end of said male thread, and a female thread for accepting said male thread of said sealing member is formed on said cooling liquid container.
- 5. A display apparatus as claimed in claim 3, wherein said sealing member has a male thread and has a head provided on the end of said male thread, and a female thread for accepting said male thread of said sealing member is formed on said cooling liquid container.
- 6. A display apparatus as claimed in claim 1, wherein cooling liquid contained in said cooling liquid container cools the front and side faces of said cathode ray tube.
- 7. A display apparatus as claimed in claim 1, wherein said display apparatus is provided with the first cathode ray tube for projecting a red image, the second cathode ray tube for projecting a green image, and the third cathode ray tube for projecting a blue image, and images projected by said cathode ray tubes are projected onto a target through projection lenses.
- 8. A display apparatus as claimed in claim 1, wherein an image projected from a cathode ray tube is projected onto a target on the back side of a screen namely a target.
- 9. A display apparatus as claimed in claim 1, wherein an image projected from a cathode ray tube is projected onto a target on the front side of a screen namely a target.
Priority Claims (1)
Number |
Date |
Country |
Kind |
10-031485 |
Feb 1998 |
JP |
|
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A |
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A |
5877583 |
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A |
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