Title: Projection display for a aircraft cockpit environment
Abstract: A projection display is provided according to one embodiment of the invention. The projection display includes a hollow case including a window opening, a screen formed on one portion of the case, and at least one mirror internally mounted to the case at a position to reflect light from the window opening to the screen. The projection display further includes a window mounted in the window opening. The projection display further includes an optical engine mounted to the case. The optical engine is positioned over the window and oriented so that emitted light from the optical engine is directed onto the at least one mirror. The projection display further includes a diaphragm internally attached to the case and dividing an internal volume of the case into a first portion and a second portion. The projection display further includes a gas filling the second portion of the case at an overpressure and a vent communicating with the first portion of the case and communicating with an external environment. The vent at least partially equalizes the overpressure of the second portion with a pressure of the external environment.
Patent Number: 6,972,788 Issued on 12/06/2005 to Robertson, et al.
| Inventors:
|
Robertson; Richard L. (Cedar Rapids, IA);
Woytassek; Mark A. (Cedar Rapids, IA);
Dehmlow; Brian P. (Canton, MI)
|
| Assignee:
|
Rockwell Collins (Cedar Rapids, IA)
|
| Appl. No.:
|
058604 |
| Filed:
|
January 28, 2002 |
| Current U.S. Class: |
348/187; 348/123; 348/744; 348/748; 348/825; 359/630; 353/119; 345/7; 454/76 |
| Intern'l Class: |
H04N 005/64; H04N 009/31 |
| Field of Search: |
348/123,187,744-745,748,825,12
359/630-631
353/119
345/7
454/71,76
04/N,N
|
References Cited [Referenced By]
U.S. Patent Documents
Primary Examiner: Yenke; Brian P.
Attorney, Agent or Firm: Jensen; Nathan O., Eppele; Kyle
Claims
1. A projection display, comprising:
a hollow case including a window opening;
a screen formed on one portion of said case;
at least one mirror internally mounted in said case at a position to reflect
light from said window opening to said screen;
a window mounted in said window opening;
an optical engine mounted to said case, with said optical engine being positioned
over said window and oriented so that emitted light from said optical engine is
directed onto said at least one mirror;
a diaphragm internally attached to said case and dividing an internal volume
of said case into a first portion and a second portion;
a gas filling said second portion of said case at an overpressure; and
a vent communicating with said first portion of said case and communicating with
an external environment to at least partially equalize said overpressure of said
second portion with a pressure of said external environment.
2. The projection display of claim 1, wherein said diaphragm comprises a flexible diaphragm.
3. The projection display of claim 1, said vent allows atmospheric air into said
first portion.
4. The projection display of claim 1, wherein said at least one port comprises
two ports, with a first port comprising an inlet for introducing said dry, inert
gas into said second portion of said case and a second port comprising an outlet
for removing atmospheric air from said second portion of said case during said
introducing of said dry, inert gas.
5. The projection display of claim 1, wherein said gas comprises a dry, inert gas.
6. The projection display of claim 1, wherein said gas comprises nitrogen.
7. The projection display of claim 1, wherein said optical engine is positioned
below said screen.
8. The projection display of claim 1, wherein said optical engine is removably
mounted to said case.
9. The projection display of claim 1, further comprising a flexible dust boot
interposed between said optical engine and said case.
10. The projection display of claim 1, further comprising a seal positioning
in said window opening.
11. A projection display, comprising:
a hollow case including a window opening;
a screen formed on one portion of said case;
at least one mirror internally mounted to said case at a position to reflect
light from said window opening to said screen;
a seal positioned in said window opening;
a window mounted in said window opening and sealingly retained therein by said seal;
an optical engine removably mounted to said case, with said optical engine being
positioned over said window and oriented so that emitted light from said optical
engine is directed onto said at least one mirror;
a flexible dust boot interposed between said optical engine and said case;
a diaphragm internally attached to said case and dividing an internal volume
of said case into a first portion and a second portion;
a vent opening formed in said case and positioned in said first portion and communicating
with said first portion, with said vent opening allowing atmospheric air into said
first portion;
a dry, inert gas filling said second portion of said case at an overpressure; and
two sealable ports communicating with an interior of said second portion of said
case, with a first port comprising an inlet for introducing said dry, inert gas
into said second portion of said case and a second port comprising an outlet for
removing atmospheric air from said second portion during said introducing of said
dry, inert gas.
12. The projection display of claim 11, wherein said diaphragm comprises a flexible diaphragm.
13. The projection display of claim 11, wherein said dry, inert gas comprises nitrogen.
14. The method of claim 11, wherein said optical engine is positioned below said screen.
15. A method of forming a projection display, comprising the steps of:
forming a hollow case including a window opening and a screen;
affixing at least one mirror to an internal surface of said case at a position
to reflect light from said window opening onto said screen;
applying a seal to said window opening;
sealingly mounting a window in said window opening and retained in said window
opening by said seal;
mounting an optical engine to said case, with said optical engine being positioned
over said window and oriented so that emitted light from said optical engine is
directed onto said at least one mirror;
providing a flexible dust boot between said optical engine and said case;
sealingly attaching a diaphragm to an interior region of said case, said diaphragm
dividing an internal volume of said case into a first portion and a second portion;
supplying a dry, inert gas to said second portion of said case using a first port;
evacuating atmospheric air from said second portion of said case using a second
port; and
pressurizing said second portion of said case with said dry, inert gas to an overpressure.
16. The method of claim 15, further comprising forming a vent opening in said
case and positioned in said first portion and communicating with said first portion,
with said vent opening allowing atmospheric air into said first portion.
17. The method of claim 15, wherein the step of supplying a dry, inert gas comprises
supplying nitrogen.
18. The method of claim 15, wherein said optical engine is mounted to said case
in a position below said screen.
Description
FIELD OF THE INVENTION
The present invention relates generally to projection display devices, and more
particularly to a projection display for an aircraft cockpit environment.
BACKGROUND OF THE INVENTION
Modern aircraft cockpit instrumentation includes many complex electronic systems,
including avionics, navigation systems, communications, engine and system gauges,
etc. They are visual instrument systems that the aircraft crew use in operating
the aircraft. Therefore, proper operation of all cockpit instruments is of the
greatest importance. In addition, the cockpit instrumentation must be highly reliable
in order to provide safe, reliable, and economical air travel.
Prior art aircraft cockpit instrumentation has used projection displays. A
projection display includes an optical image engine that creates and projects an
electronically created image onto a screen. The resultant image can be viewed by
one or more of the crew. The projection display may include one or more mirrors
to reflect the image onto a screen at a desired position. The projection display
can create any manner of visual display, including instrument representations,
navigation displays, aircraft attitude displays, etc. In addition, the projection
display may be switched between a plurality of display types.
However, the projection displays of the prior art have drawbacks. In the
prior art, the optical engine portion of the projected display is generally mounted
at the rear of the projection display device. The optical engine is therefore located
well behind the instrument panel of an aircraft. The result is difficult maintenance
of the projection display and difficult replacement of the optical engine. Anyone
familiar with maintenance of electrical and mechanical systems is aware that complicated
and inconveniently installed machinery is harder to repair correctly and therefore
more prone to failure.
In another drawback, the prior art projection display is not sealed. Because
the
cockpit environment is not completely clean, dust and dirt may float around and
may be stirred up by ventilation or by flight maneuvers. The dirt may work its
way into the prior art projection display and cause degraded performance or even
failure of the device. In addition, the cockpit environment may contain moisture
which can cause corrosion or condensation that interferes with the display.
What is needed therefore are improvements to aircraft cockpit projection displays.
SUMMARY OF THE INVENTION
A projection display is provided according to one embodiment of the invention.
The projection display comprises a hollow case including a window opening, a screen
formed on one portion of the case, and at least one mirror internally mounted to
the case at a position to reflect light from the window opening to the screen.
The projection display further comprises a window mounted in the window opening.
The projection display further comprises an optical engine mounted to the case.
The optical engine is positioned over the window and oriented so that emitted light
from the optical engine is directed onto the at least one mirror. The projection
display further comprises a diaphragm internally attached to the case and dividing
an internal volume of the case into a first portion and a second portion. The projection
display further comprises a gas filling the second portion of the case at an overpressure
and a vent communicating with the first portion of the case and communicating with
an external environment. The vent at least partially equalizes the overpressure
of the second portion with a pressure of the external environment.
According to a second embodiment the projection display comprises a hollow
case including a window opening, a screen formed on one portion of the case, and
at least one mirror internally mounted to the case at a position to reflect light
from the window opening to the screen. The projection display further comprises
a seal positioned in the window opening and a window mounted in the window opening
and sealingly retained therein by the seal. The projection display further comprises
an optical engine removably mounted to the case. The optical engine is positioned
over the window and oriented so that emitted light from the optical engine is directed
onto the at least one mirror. The projection display further comprises a flexible
dust boot interposed between the optical engine and the case. The projection display
further comprises a diaphragm internally attached to the case and dividing an internal
volume of the case into a first portion and a second portion. The projection display
further comprises a vent opening or a sealable port formed in the case and positioned
in the first portion and communicating with the first portion. The vent opening
allows atmospheric air into the first portion. The projection display further comprises
a dry, inert gas filling the second portion of the case at an overpressure and
two sealable ports communicating with an interior of the second portion of the
case. The first port comprises an inlet for introducing the dry, inert gas into
the second portion of the case. The second port comprises an outlet for removing
atmospheric air from the second portion of the case during the introduction of
the dry, inert gas.
A method of forming a projection display comprises the steps of forming a hollow
case including a window opening and a screen and affixing at least one mirror to
an internal surface of the case at a position to reflect light from the window
opening onto the screen. The method further comprises the steps of applying a seal
to the window opening and sealingly mounting a window in the window opening and
retained in the window opening by the seal. The method further comprises the steps
of mounting an optical engine to the case. The optical engine is positioned over
the window and oriented so that emitted light from the optical engine is directed
onto the at least one mirror. The method further comprises the steps of providing
a flexible dust boot between the optical engine and the case. The method further
comprises the steps of sealingly attaching a diaphragm to an interior region of
the case. The diaphragm divides an internal volume of the case into a first portion
and a second portion. The method further comprises the steps of supplying a dry,
inert gas to the second portion of the case using a first port, evacuating atmospheric
air from the second portion of the case using a second port, and pressurizing the
second portion of the case with the dry, inert gas to an overpressure.
The above and other features and advantages of the present invention will be
further understood from the following description of the preferred embodiments
thereof, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a projection display according to one embodiment of the invention; and
FIG. 2 shows detail of the mounting of the window in the case.
DETAILED DESCRIPTION
FIG. 1 shows a projection display
100 according to one embodiment of
the invention. The projection display
100 includes a case
105, a
window
108, an optical engine
111, a dust boot
116, at least
one mirror
122, a screen
127, a seal
135, a diaphragm
138,
two external ports
140 and
142, an inert gas mixture
155,
and an optional vent opening
162.
The case
105 is hollow and when the projection display
100 is fully
assembled the case
105 is capable of containing a gas or gas mixture at
an appropriate overpressure condition. The case
105 may be formed of a strong,
light, non-porous material such as: aluminum, titanium, composite material, etc.
The overpressure can be as little as about 5 pounds per square inch (psi), but
in addition, the case
105 may support overpressures due to altitude changes
from sea level to very high altitudes. The case
105 includes the screen
127, which may be translucent and may be formed as one end wall of the case
105. At least one first surface mirror
122 is placed in the back
surface of the case
105 in a region and at an angle to direct the image
from the optical engine
111 to be focused onto the screen
127. More
than one mirror may be used, as required or desired.
FIG. 2 shows detail for one method of the mounting of the window
108
in the case
105. The window
108 is placed in an opening in the case
105 and is sealed therein by a seal
135. The seal
135 may
be rubber, nylon, silicon, etc. The seal
135 is positioned between the window
108 and the window opening of the case
105, on an extending lip
137.
The seal
135 therefore creates an essentially air-tight seal between the
window
108 and the case
105. The window
108 is transparent,
and may be glass or plastic, for example.
The optical engine
111 may be any type of common projection display optical
engine. The optical engine
111 mounts to the outside of the case
105,
and is substantially centered on the window
108, wherein the image generated
by the optical engine
111 passes through the window
108. The dust
boot
116 is a flexible ring that is positioned between the optical engine
111 and the case
105 and prevents dust from getting in between the
optical engine
111 and the window
108. The dust boot
116 may
be formed of any manner of compliant material. As a result, the optical path of
the emitted light is fully contained within the sealed projection display
100.
The diaphragm
138 may be any type of flexible membrane, such as a rubber
membrane for example. The diaphragm
138 is internally attached to the case
105 and may flex in response to pressure within the case
105. As
a result, the diaphragm
138 divides an internal volume of the case
105
into a first portion
106 and a second portion
107. Behind the diaphragm
may be the optional vent opening
162 in the case
105 that allows
the cabin air environment to enter into the small region covered by the diaphragm
138 (i.e., the first portion
106). The vent opening
162 is
located in the first portion
106 and allows atmospheric air to enter or
leave the first portion
106. The diaphragm
138 may flex in order
to accommodate cabin air pressure differences. The diaphragm
138 therefore
may at least partially equalize the overpressure in the case
105 with a
pressure of the external environment. This minimizes strain on the seals of the
projection display
100 due to changes in the cabin air pressure.
The two external ports
140 and
142 may be sealable and may be used
to admit gas into and evacuate gas from the second portion
107 of the case
105. During manufacture, a first port
140 may be used to introduce
an inert gas mixture, while a second port
142 may be used to evacuate atmospheric
air. Therefore, the two ports
140 and
142 may be used to create an
overpressure inert gas atmosphere inside the second portion
107 of the case
105 during manufacture. The two ports may then be closed in order to maintain
the overpressure inert gas atmosphere in the second portion
107. The inert
gas mixture
155 may be any type of dry inert gas, such as nitrogen, for
example, or may be a mixture of gases. The overpressure is maintained in order
to prevent moisture and atmospheric air from entering the projection display
100.
It should be understood that although two ports are discussed above, the projection
display
100 may be constructed with only one port. In a single port embodiment,
the case
105 may be substantially evacuated and then filled to a slight
overpressure using only one port. The drawback of a single port embodiment is that
the evacuation and pressurization will take longer and the evacuation of atmospheric
air may not be as complete as in a two port embodiment.
The projection display
100 may be manufactured by forming a hollow case
105, including a window opening and a screen
127. At least one mirror
122 is affixed to an internal surface of the case
105 at a position
to reflect light from the window opening onto the screen
127. A seal
135
is applied to the window opening of the case
105, and a window
108
is applied to the window opening, wherein the seal
135 sealingly retains
the window
108 in the window opening. An optical engine
111 is mounted
to the case, with the optical engine
111 being positioned over the window
108 and oriented so that emitted light from the optical engine
111
is directed onto the at least one mirror
122. A flexible dust boot is provided
between the optical engine
111 and the case
105. A diaphragm
138
is sealingly attached to an interior region of the case
105, with the diaphragm
138 dividing an internal volume of the case
105 into a first portion
106 and a second portion
107. A dry, inert gas mixture is supplied
to the second portion
107 of the case
105 using a first port
140.
Atmospheric air in the second portion
107 of the case
105 is evacuated
substantially simultaneously using a second port
142. The case
105
is pressurized with the dry, inert gas mixture
155 to a slight overpressure.
The projection display
100 according to the invention presents several
benefits. Due to the pressure regulation provided by the diaphragm
138,
there is less stress on the case
105 and on the sealing components. Therefore,
the projection display
100 is less likely to leak and will last longer.
Moreover, the inert dry gas interior environment will prevent corrosion and will
prevent condensation within the case
105. In addition, the optical engine
111 is mounted at a lower front region of the projection display
100.
The mounting arrangement therefore provides easy access to the optical engine
111
from the aircraft cockpit. The mount therefore allows easy maintenance and replacement.
Moreover, due to the sealed nature of the projection display
100, dirt or
moisture cannot get inside the casing. Problems such as corrosion, condensation
and fogging, dirt in working components, etc., are thereby prevented.
While the invention has been described in detail above, the invention is not
intended to be limited to the specific embodiments as described. It is evident
that those skilled in the art may now make numerous uses and modifications of and
departures from the specific embodiments described herein without departing from
the inventive concepts.
*
