U.S. patent application number 14/334886 was filed with the patent office on 2015-04-02 for image projection apparatus.
This patent application is currently assigned to RICOH COMPANY, LTD.. The applicant listed for this patent is Tetsuya FUJIOKA, Naoyuki ISHIKAWA, Hideo KANAI, Akihisa MIKAWA, Yasunari MIKUTSU, Yukimi NISHI, Satoshi TSUCHIYA, Masamichi YAMADA. Invention is credited to Tetsuya FUJIOKA, Naoyuki ISHIKAWA, Hideo KANAI, Akihisa MIKAWA, Yasunari MIKUTSU, Yukimi NISHI, Satoshi TSUCHIYA, Masamichi YAMADA.
Application Number | 20150092165 14/334886 |
Document ID | / |
Family ID | 52145633 |
Filed Date | 2015-04-02 |
United States Patent
Application |
20150092165 |
Kind Code |
A1 |
MIKAWA; Akihisa ; et
al. |
April 2, 2015 |
IMAGE PROJECTION APPARATUS
Abstract
An image projection apparatus includes: a light source; an
exhaust fan having a rotary shaft provided with at least one blade,
the rotary shaft being rotated to exhaust air inside the apparatus
to the outside of the apparatus; a guide having a sloped face that
is sloped toward the exhaust fan, the sloped face having a first
side surface facing the light source and a second side surface
provided opposite of the first side surface; a first flow path,
defined by the first side surface of the guide, to guide air heated
by the light source toward the rotary shaft of the exhaust fan; and
a second flow path, defined by the second side surface of the
guide, to guide air having temperature lower than temperature of
the air heated by the light source, toward the rotary shaft of the
exhaust fan.
Inventors: |
MIKAWA; Akihisa; (Kanagawa,
JP) ; FUJIOKA; Tetsuya; (Kanagawa, JP) ;
KANAI; Hideo; (Tokyo, JP) ; YAMADA; Masamichi;
(Kanagawa, JP) ; MIKUTSU; Yasunari; (Tokyo,
JP) ; TSUCHIYA; Satoshi; (Kanagawa, JP) ;
ISHIKAWA; Naoyuki; (Kanagawa, JP) ; NISHI;
Yukimi; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MIKAWA; Akihisa
FUJIOKA; Tetsuya
KANAI; Hideo
YAMADA; Masamichi
MIKUTSU; Yasunari
TSUCHIYA; Satoshi
ISHIKAWA; Naoyuki
NISHI; Yukimi |
Kanagawa
Kanagawa
Tokyo
Kanagawa
Tokyo
Kanagawa
Kanagawa
Tokyo |
|
JP
JP
JP
JP
JP
JP
JP
JP |
|
|
Assignee: |
RICOH COMPANY, LTD.
Tokyo
JP
|
Family ID: |
52145633 |
Appl. No.: |
14/334886 |
Filed: |
July 18, 2014 |
Current U.S.
Class: |
353/61 |
Current CPC
Class: |
G03B 21/16 20130101 |
Class at
Publication: |
353/61 |
International
Class: |
G03B 21/16 20060101
G03B021/16 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 2, 2013 |
JP |
2013-207712 |
Claims
1. An image projection apparatus, comprising: a light source
configured to irradiate light to project a projection image; an
exhaust fan having a rotary shaft provided with at least one blade,
the rotary shaft being rotated to exhaust air inside the apparatus
to the outside of the apparatus; a guide having a sloped face that
is sloped toward the exhaust fan, the sloped face having a first
side surface facing the light source and a second side surface that
is a back surface of the first side surface; a first flow path,
defined by the first side surface of the guide, to guide air heated
by the light source toward the rotary shaft of the exhaust fan; and
a second flow path, defined by the second side surface of the
guide, to guide air having temperature lower than temperature of
the air heated by the light source, toward the rotary shaft of the
exhaust fan, wherein the second flow path is made narrower at an
exhaust section from which the air is exhausted than at an intake
section from which the air is taken.
2. The image projection apparatus of claim 1, wherein the sloped
face of the guide is made so as to gradually narrow the second flow
path to increase the flow velocity of the air guided by the second
flow path.
3. (canceled)
4. The image projection apparatus of claim 1, wherein the flow
velocity of the air guided by the second flow path is higher than
the flow velocity of the air guided by the first flow path, at an
end portion of the guide facing the exhaust fan.
5. The image projection apparatus of claim 1, wherein the guide has
an end portion facing the exhaust fan, which is provided at a
height substantially the same as a height of the rotary shaft of
the exhaust fan.
6. The image projection apparatus of claim 1, wherein the guide has
an end portion facing the exhaust fan, which is provided at a
location facing the rotary shaft of the exhaust fan.
7. The image projection apparatus of claim 1, wherein the sloped
face has a step-wise structure.
8. The image projection apparatus of claim 1, wherein the guide has
an end portion facing the exhaust fan, which forms a space with the
exhaust fan.
9. The image projection apparatus of claim 8, wherein the guide has
an end portion facing the exhaust fan, which is located at a
distance away from the exhaust fan, so as to sufficiently attract
the air guided by the second flow path to the air guided by the
first flow path.
10. The image projection apparatus of claim 1, further comprising:
a power supply unit, wherein the air guided by the second flow path
cools the power supply unit as the air passes along the power
supply unit.
11. The image projection apparatus of claim 1, further comprising:
a first intake duct to take the outside air into the first flow
path; and a second intake duct to take the outside air into the
second flow path.
12. The image projection apparatus of claim 11, wherein the second
intake duct is provided at a location facing the exhaust fan.
13. The image projection apparatus of claim 12, wherein the first
intake duct is provided at a surface of the apparatus that is
different than a surface of the apparatus where the second intake
duct is provided.
14. The image projection apparatus of claim 13, wherein the first
intake duct is provided at a location having a distance to the
light source that is shorter than a distance to the second intake
duct.
15. The image projection apparatus of claim 1, further comprising:
an image forming element to form the projection image, wherein the
air guided by the first flow path includes air used for cooling the
image forming element.
16. The image projection apparatus of claim 1, further comprising:
a stirring unit that stirs the air guided by the guide.
17. The image projection apparatus of claim 16, wherein the
stirring unit is provided at the rotary shaft of the exhaust
fan.
18. The image projection apparatus of claim 17, wherein the
stirring unit is provided on a rotary axis of the exhaust fan.
19. The image projection apparatus of claim 18, wherein the
stirring unit is provided at a distance away from the rotary shaft
of the exhaust fan.
20. The image projection apparatus of claim 1, wherein the guide
guides the air heated at the light source such that the air heated
at the light source flows toward the rotary shaft while ascending
as ascending airflow.
21. The image projection apparatus of claim 20, wherein the air
having lower temperature flows toward the rotary shaft without
being raised by the ascending airflow of the air heated at the
light source.
22. An image projection apparatus, comprising: a light source
configured to irradiate light to project a projection image; a
holder configured to support the light source, the holder having an
exhaust duct for exhausting air heated by the light source; an
exhaust fan having a rotary shaft provided with at least one blade,
the rotary shaft being rotated to exhaust air inside the image
projection apparatus to the outside of the image projection
apparatus; and a guide configured to guide air exhausted from the
exhaust duct and air that is not exhausted from the exhaust duct
toward the rotary shaft of the exhaust fan, the guide having a
sloped face that is sloped upward to the exhaust fan so that the
air exhausted from the exhaust duct is guided by the guide while
ascending as ascending airflow, the sloped face having a first side
surface facing the light source and a second side surface that is a
back surface of the first side surface, the first side surface
defining a first flow path to guide air heated by the light source
toward the rotary shaft of the exhaust fan, the second side surface
defining a second flow path to guide air having temperature lower
than temperature of the air heated by the light source toward the
rotary shaft of the exhaust fan, wherein the second flow path is
made narrower at an exhaust section from which the air is exhausted
than at an intake section from which the air is taken.
23. The image projection apparatus of claim 21, wherein the air
that is not exhausted from the exhaust duct flows toward the rotary
shaft without being raised by the ascending airflow of the air
heated at the light source.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is based on and claims priority
pursuant to 35 U.S.C. .sctn.119(a) to Japanese Patent Application
No. 2013-207712, filed on Oct. 2, 2013, in the Japan Patent Office,
the entire disclosure of which is hereby incorporated by reference
herein.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to an image projection
apparatus such as a projector.
[0004] 2. Description of the Related Art
[0005] The image projection apparatuses form an image based on
image data received from a personal computer, a video camera or the
like, using light emitted from a light source, and project the
image on a screen or the like.
[0006] As the light source of the image projection apparatus, a
halogen lamp, a metal halide lamp, a high-pressure mercury lamp and
the like may be used. These lamps usually become a high temperature
when emitting the light. To cool the light source, a blowing unit
such as a blower or a fan may be provided to circulate air. Air
that flows through the light source increases in temperature by
drawing heat from the light source. Such air, which becomes a high
temperature, is discharged from an exhaust duct.
SUMMARY
[0007] Example embodiments of the present invention include an
image projection apparatus including: a light source; an exhaust
fan having a rotary shaft provided with at least one blade, the
rotary shaft being rotated to exhaust air inside the apparatus to
the outside of the apparatus; a guide having a sloped face that is
sloped toward the exhaust fan, the sloped face having a first side
surface facing the light source and a second side surface provided
opposite of the first side surface; a first flow path, defined by
the first side surface of the guide, to guide air heated by the
light source toward the rotary shaft of the exhaust fan; and a
second flow path, defined by the second side surface of the guide,
to guide air having temperature lower than temperature of the air
heated by the light source, toward the rotary shaft of the exhaust
fan.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0008] A more complete appreciation of the disclosure and many of
the attendant advantages and features thereof can be readily
obtained and understood from the following detailed description
with reference to the accompanying drawings, wherein:
[0009] FIG. 1 is an external perspective view illustrating a
projector and a projection plane according to an embodiment of the
present invention;
[0010] FIG. 2A is a perspective view of the interior of the
projector according to an embodiment of the present invention as
viewed from the front side of FIG. 1;
[0011] FIG. 2B is a perspective view of the interior of the
projector according to an embodiment of the present invention as
viewed from the back side of FIG. 1;
[0012] FIG. 3 is an explanatory diagram illustrating an optical
path from the projector to a projection plane according to an
embodiment of the present invention;
[0013] FIG. 4 is a perspective view of an optical engine and a
light source provided inside the projector according to an
embodiment of the present invention;
[0014] FIG. 5 is a perspective view of the light source according
to an embodiment of the present invention;
[0015] FIG. 6 is a perspective view of an illumination unit
according to an embodiment of the present invention;
[0016] FIG. 7 is a perspective view of the illumination unit, the
projection lens, and the light modulator according to an embodiment
of the present invention as viewed from a direction A of FIG.
6;
[0017] FIG. 8 is an explanatory diagram illustrating the optical
path in the illumination unit according to an embodiment of the
present invention;
[0018] FIG. 9 is a perspective view of the light modulator
according to an embodiment of the present invention;
[0019] FIG. 10 is a perspective view illustrating a second optical
system held by a second projection optical system according to an
embodiment of the present invention, together with the projection
lens, the illumination unit, and the light modulator;
[0020] FIG. 11 is a perspective view illustrating the second
projection optical system according to an embodiment of the present
invention, together with a first projection optical system, the
illumination unit, and the light modulator;
[0021] FIG. 12 is a perspective view illustrating the optical path
from the first optical system to the projection plane according to
an embodiment of the present invention;
[0022] FIG. 13 is a perspective view illustrating the projector on
an installation surface side according to an embodiment of the
present invention;
[0023] FIG. 14 is a schematic diagram illustrating an arrangement
relation of each part in the apparatus according to an embodiment
of the present invention;
[0024] FIG. 15 is a diagram illustrating an internal configuration
of the projector according to an embodiment of the present
invention;
[0025] FIG. 16 is an explanatory diagram illustrating the flow of
air in the projector according to an embodiment of the present
invention;
[0026] FIG. 17 is a perspective view illustrating a light source
blower, a light source duct, a light source unit, and a fluid guide
according to an embodiment of the present invention;
[0027] FIG. 18 is a perspective view illustrating the light
modulator, the illumination unit, and an intake blower according to
an embodiment of the present invention;
[0028] FIG. 19 is a cross-sectional view illustrating the flow of
air above the light source housing according to an embodiment of
the present invention;
[0029] FIG. 20 is a diagram as seen from a direction of an arrow a
of FIG. 21;
[0030] FIG. 21 is a cross-sectional view illustrating the flow of
air above the light source housing according to a first modified
example of the present invention;
[0031] FIG. 22 is a perspective view illustrating an exhaust fan
according to the first modified example of the present
invention;
[0032] FIG. 23 is a perspective view illustrating an aspect in
which a stirring member is formed in a prismatic shape according to
an embodiment of the present invention;
[0033] FIGS. 24A and 24B are diagrams illustrating an aspect in
which the stirring member is provided at a position deviated from
the center of rotary shaft of the exhaust fan according to an
embodiment of the present invention;
[0034] FIG. 25 is a perspective view illustrating the flow of air
above a light source housing of an image projection apparatus of
the related art; and
[0035] FIG. 26 is a cross-sectional view illustrating the flow of
air above the light source housing of the image projection
apparatus of the related art.
[0036] The accompanying drawings are intended to depict example
embodiments of the present invention and should not be interpreted
to limit the scope thereof. The accompanying drawings are not to be
considered as drawn to scale unless explicitly noted.
DETAILED DESCRIPTION
[0037] Hereinafter, an embodiment of the present invention will be
described with reference to the drawings.
[0038] First, an overall configuration of the image projection
apparatus, which may be provided with a light receiving device,
will be described according to an embodiment of the present
invention.
[0039] FIG. 1 is an external perspective view illustrating a
projector 1 as an image projection apparatus according to an
embodiment of the present invention, and a projection plane 2 such
as a screen. In the following description, as illustrated in FIG.
1, a normal direction of the projection plane 2 is defined as an
X-direction, a direction (a vertical direction) of a minor axis of
the projection plane is defined as a Y-direction, and a direction
(a horizontal direction) of a major axis of the projection plane 2
is defined as a Z-direction.
[0040] The projector 1 is an apparatus that forms a projection
image based on image data input from a personal computer, a video
camera or the like, and projects the projection image P on the
projection plane 2 such as a screen. In a liquid crystal projector,
recently, an improvement in brightness, a cost reduction and the
like accompanied by high resolution of the liquid crystal panel,
and high efficiency of the light source (lamp) have been in
progress. Furthermore, a small light projector using a digital
micro-mirror device (DMD) as a micro drive mirror device is in
widespread use, and the projector has come to be widely used even
in homes as well as in offices and schools. Furthermore, a
front-type projector has improved in portability and has come to be
used even in small meeting of several people. In such a projector,
there have been requests for enabling the projection of the image
of a large screen (increase in screen size of the projection plane)
and enabling the reduction of "projection space required other than
the projector" as much as possible. As will be described below, the
projector 1 of the present embodiment is configured so that a
transparent optical system such as a projection lens is set in
parallel to the projection plane 2, and after reflecting the
optical flux at a reflective mirror, the optical flux expands and
reflects with respect to the projection plane 2 by a free-form
surface mirror. With this configuration, an upright optical engine
can be downsized.
[0041] A dust-proof glass 51 is mounted on the upper surface of the
projector 1. The optical flux passing through the dust-proof glass
51 is projected onto the projection plane 2 to form the projection
image P on the projection plane 2. In addition, an operation unit
83 for allowing a user to operate the projector 1 is provided on
the upper surface of the projector 1. Furthermore, a focus lever 33
for adjusting the focus is provided on the side surface of the
projector 1.
[0042] FIGS. 2A and 2B are a perspective view illustrating the
interior of the projector 1 with a main body cover of the projector
1 removed. FIG. 2A is a perspective view of the interior of the
projector 1 as viewed from the front side of FIG. 1, and FIG. 2B is
a perspective view of the interior of the projector 1 as viewed
from the back side of FIG. 1. Furthermore, FIG. 3 is a view of an
optical path from the projector 1 to the projection plane 2.
[0043] The projector 1 is provided with an optical engine 100, and
a light source unit 60 having a light source that emits white
light. The optical engine 100 is provided with an image forming
unit 101 that forms an image using the light from the light source,
and a projection optical system 102 that projects the optical flux
of the image formed by the image forming unit 101 onto the
projection plane 2.
[0044] The image forming unit 101 (FIG. 3) includes a light
modulator 10, and an illumination unit 20. The light modulator 10
has a DMD 12 serving as a micro drive mirror device that has a
number of micro mirrors, which may be movable to vary the slope of
the reflection surface. The illumination unit 20 reflects the light
from the light source to the DMD 12 with light. The projection
optical system 102 includes a first projection optical system 30, a
curved mirror 42, and a second projection optical system 40. The
first projection optical system 30 includes at least one refractive
optical system of a transmission type and is provided with a
coaxial optical system 70 having positive power. The second
projection optical system 40 has a reflecting mirror 41, and a
curved mirror 42 having the positive power.
[0045] Light from the light source is illuminated by the
illumination unit 20, and by modulating the light illuminated by
the illumination unit 20, an image is generated on the DMD 12. The
light image generated by the DMD 12 is projected onto the
projection plane 2 via the optical system 70 of the first
projection optical system 30, the reflecting mirror 41 and the
curved mirror 42 of the second projection optical system 40.
[0046] FIG. 4 is a perspective view of the optical engine 100 and
the light source unit 60 provided inside the projector 1.
[0047] As illustrated in FIG. 4, the light modulator 10, the
illumination unit 20, the first projection optical system 30, and
the second projection optical system 40, collectively forming the
optical engine 100 are arranged in parallel to the Y-direction of
FIG. 4 of the direction parallel to the projection plane 2 and the
image plane of the projection image P. Furthermore, the light
source unit 60 is disposed on the right side of the illumination
unit 20 in FIG. 4. Furthermore, reference numerals 32a1 and 32a2
illustrated in FIG. 4 indicate legs of a lens holder 32 of the
first projection optical system 30, and reference numeral 263
indicates a screw unit for screwing the light modulator 10 into the
illumination unit 20.
[0048] FIG. 5 is a schematic perspective view of the light source
unit 60.
[0049] The light source unit 60 has a light source bracket 62, and
a light source 61 such as a halogen lamp, a metal halide lamp, or a
high-pressure mercury lamp that is mounted on the upper surface of
the light source bracket 62. The light source bracket 62 is
provided with a connector 62a to connect to a power supply
connector connected to a power supply unit (not illustrated). The
connector 62a is provided on one end side in a longitudinal
direction (Z-direction) of the light source unit 60.
[0050] Furthermore, on the light emitting side of the light source
61 at the top of the light source bracket 62, (the other end side
in the longitudinal direction of the light source unit 60), a
holder 64 as a holding member on which a reflector (not
illustrated) is held is screwed. On the surface of the holder 64 on
the opposite side to the arrangement side of the light source 61,
an emission window 63 is provided. Light emitted from the light
source 61 is focused on the emission window 63 by a reflector (not
illustrated) held by the holder 64, and is emitted from the
emission window 63.
[0051] Furthermore, on the upper surface of the holder 64, and at
both ends in the X-direction of the lower surface of the holder 64,
light source positioning units 64a1, 64a2, and 64a3 for positioning
the light source unit 60 at the lighting bracket 26 (see FIG. 6) of
the illumination unit 20 are provided. The two light source
positioning units 64a1 and 64a2 provided on the lower surface of
the holder 64 are formed as holes. The light source positioning
unit 64a3 provided on the upper surface of the holder 64 is formed
as a projection.
[0052] Furthermore, on the side surface of the holder 64, a light
source air supply port 64b into which air for cooling the light
source 61 flows is provided, and on the upper surface of the holder
64, a light source exhaust duct 64c through which the air heated by
heat of the light source 61 is exhausted is provided.
[0053] The light source bracket 62 is provided with a handle 68 in
which a user picks the handle with his fingers to extract the light
source unit 60 at the time of replacement of the light source unit
60. The handle 68 is rotatably attached to the light source bracket
62 at the substantially center of the connector 62a and the light
source positioning units 64a1 and 64a2 in the longitudinal
direction of the light source bracket 62 (Z-direction in the
drawings). The handle 68 may also have an appropriate shape to the
extent that a user picks the handle with finger leading ends, in
addition to the illustrated shape.
[0054] FIG. 6 is a perspective view of the illumination unit 20
which illustrates the optical system components stored in the
illumination unit 20 along with other components.
[0055] As illustrated in FIG. 7, the illumination unit 20 has a
color wheel 21, a light tunnel 22, two sheets of relay lenses 23, a
cylindrical mirror 24, and a concave mirror 25. These components
are held in the lighting bracket 26. The lighting bracket 26 has a
box-shaped portion 261 in which two sheets of relay lenses 23, the
cylindrical mirror 24, and the concave mirror 25 are housed. Among
four side surfaces of the box-shaped portion 261, only a right side
of the drawings has a side surface, and other three surfaces have
an opened shape. Moreover, an OFF light plate 27 (see FIG. 8) is
attached to the side surface opening of the back side in the
X-direction in the drawings, and a cover member (not illustrated)
is attached to the side surface opening of the front side in the
X-direction of the drawings. Thus, the two sheets of relay lenses
23, the cylindrical mirror 24, and the concave mirror 25 housed in
the box-shaped portion 261 of the lighting bracket 26 are covered
by the lighting bracket 26, the OFF light plate 27, and a cover
member.
[0056] Furthermore, on the lower surface of the box-shaped portion
261 of the lighting bracket 26, an irradiating through-hole 26d
through which the DMD 12 is exposed is formed.
[0057] In addition, the lighting bracket 26 has three legs 29. The
legs 29 support the weight of the first projection optical system
30 and the second projection optical system 40 fixed by being
stacked on the lighting bracket 26, while coming into contact with
a base member 53 (see FIG. 13) of the projector 1. Furthermore, by
providing the legs 29, a space for allowing outdoor air to flow in
is formed in a heat sink 13 (see FIG. 8) as a cooling unit for
cooling the DMD 12 of the light modulator 10.
[0058] In addition, reference numerals 32a3 and 32a4 illustrated in
FIG. 6 are the legs of the lens holder 32 of the first projection
optical system 30, and reference numeral 45a3 is a screw unit 45a3
of the second projection optical system 40.
[0059] FIG. 7 is a perspective view of the illumination unit 20,
the first projection optical system 30, and the light modulator 10
as viewed from a direction A in FIG. 6.
[0060] The first projection optical system 30 is disposed above the
illumination unit 20, and has a projection lens 31 that holds the
first optical system 70 (see FIG. 3) formed by a plurality of
lenses, and a lens holder 32 that holds the projection lens 31.
Four legs 32a1 to 32a4 extending downward are provided in the lens
holder 32 (in FIG. 7, only the legs 32a1 and 32a2 are illustrated,
and the legs 32a3 and 32a4 are illustrated in FIG. 6), and on the
bottom surfaces of the respective legs 32a1 to 32a4, screw holes
for being screwed into the lighting bracket 26 are formed.
[0061] An upper surface 26b orthogonal to the Y-direction of the
drawing is provided above the box-shaped portion 261 of the
lighting bracket 26. At four corners of the upper surface 26b,
through-holes (not illustrated) are provided through which screws
for screwing the first projection optical system 30 pass. By
inserting the screws from the through-holes to be inserted into the
screw holes formed on the bottom surfaces of the respective legs
32a1 to 32a4, the first projection optical system 30 is fastened to
the illumination unit 20.
[0062] Furthermore, a focus gear 36 is provided in the projection
lens 31, and an idler gear 35 is meshed with the focus gear 36. A
lever gear 34 is meshed with the idler gear 35, and the focus lever
33 is fixed to a rotary axis of the lever gear 34. As illustrated
in FIG. 1, a leading end of the focus lever 33 is exposed from the
apparatus main body.
[0063] When moving the focus lever 33, the focus gear 36
rotationally moves via the lever gear 34 and the idler gear 35.
When the focus gear 36 rotationally moves, the plurality of lenses
constituting the first optical system 70 in the projection lens 31
moves in a predetermined direction, respectively, and the focus of
the projection image is adjusted.
[0064] Furthermore, the lens holder 32 has screw through-holes
through which the screws 48 for screwing the second projection
optical system 40 into the first projection optical system 30 pass,
at four positions, (in FIG. 7, three screw through-holes are
illustrated, a state in which the screws 48 pass through each of
the screw through-holes is illustrated, and the leading ends of the
screw units of the screws 48 are illustrated in FIG. 7).
[0065] In the opening of the lighting bracket upper surface 26b, a
light shielding plate (not illustrated) to which the lower part of
the projection lens 31 is fitted is provided, thereby preventing
light from entering the box-shaped portion 261 from the upper
part.
[0066] At the side end of the color wheel 21 of the lighting
bracket 26 (a front side in the Z-direction in FIG. 7), a
cylindrical light source positioning target unit 26a3 vertically
formed with the through-holes is provided, and a protruding light
source positioning unit 64a3 (see FIG. 5) provided on the upper
surface of the holder 64 of the light source unit 60 described
above is fitted to the through-holes. Furthermore, two protruding
light source positioning target units 26a1 and 26a2 to which two
hole-shaped light source positioning units 64a1 and 64a2 provided
on the light source bracket 62 side of the holder 64 are fitted are
provided below the light source positioning target unit 26a3.
Moreover, the three light source positioning units 64a1 to 64a3 of
the holder 64 are fitted to the light source positioning target
units 26a1 to 26a3 of three positions provided in the lighting
bracket 26 of the illumination unit 20, and thus, the light source
unit 60 is positioned and fixed to the illumination unit 20 (see
FIG. 4).
[0067] Furthermore, the lighting bracket 26 is provided with a
lighting cover 28a that covers the color wheel 21 and the light
tunnel 22, and a wheel cover 28b that covers the surface of the
color wheel 21 facing the light source 61. The wheel cover 28b is
provided with a through-hole 281 for allowing light from the light
source 61 to pass therethrough.
[0068] FIG. 8 is an explanatory view illustrating an optical path L
in the illumination unit 20.
[0069] The color wheel 21 has a disk shape and is fixed to the
rotating part of the color motor 21a. In the color wheel 21,
filters of R (red), G (green), B (blue) and the like are provided
in a rotational direction. Light collected by a reflector (not
illustrated) provided on the holder 64 of the light source unit 60
reaches the peripheral edge of the color wheel 21 through the
emission window 63. Light reaching the peripheral edge of the color
wheel 21 is divided into light of R, G, and B in the time division
by the rotation of the color wheel 21.
[0070] Light divided by the color wheel 21 is incident on the light
tunnel 22. The light tunnel 22 has a rectangular box shape, and an
inner peripheral surface thereof is a mirror surface. Light
incident on the light tunnel 22 becomes a uniform surface light
source and is emitted toward the relay lens 23, while being
reflected by the inner peripheral surface of the light tunnel 22
several times.
[0071] Light passed through the light tunnel 22 transmits through
two relay lenses 23, is reflected by the cylindrical mirror 24 and
the concave mirror 25, and is focused on an image generation
surface of the DMD 12 to form the image.
[0072] FIG. 9 is a perspective view of the light modulator 10.
[0073] As illustrated in FIG. 9, the light modulator 10 is provided
with a DMD board 11 on which the DMD 12 is mounted. The DMD 12 is
mounted on a socket 11a provided in the DMD board 11, while causing
the image generation surface in which the micro mirrors are
arranged in a grid shape to face upward. In the DMD board 11, a
drive circuit or the like for driving the DMD mirrors is provided.
On the back surface of the DMD board 11, (surface on an opposite
side to the surface on which the socket 11a is provided), the heat
sink 13 as a cooling unit for cooling the DMD 12 is fixed.
Through-holes (not illustrated) pass through the position of the
DMD board 11 at which the DMD 12 is mounted. Projections (not
illustrated) to be inserted into the through-holes are formed in
the heat sink 13. A leading end of the projection has a flat shape.
The projections are inserted into the through-holes (not
illustrated) to bring the planes of the leading ends of the
projections into contact with the back surface (surface of an
opposite side to the image generation surface) of the DMD 12. An
elastically deformable heat transfer sheet may be adhered to the
plane and the position at which the heat sink 13 comes into contact
with the back surface of the DMD 12, thereby enhancing the adhesion
between the plane of the projection and the back surface of the DMD
12, and enhancing thermal conductivity.
[0074] The heat sink 13 is pressed against and fixed to the surface
on an opposite side to the surface of the DMD board 11 on which the
socket 11a is provided, by the fixing member 14. The fixing member
14 has a plate-like fixing portion 14a facing a portion of a right
side of FIG. 9 of the back surface of the DMD board 11, and a
plate-like fixing portion 14a facing a portion of a left side of
FIG. 9 of the back surface of the DMD board 11. A pressing portion
14b provided so as to connect the left and right fixing portions is
provided near one end and the other end in the X-direction of the
respective fixing portions.
[0075] When screwing the light modulator 10 into the lighting
bracket 26 (see FIG. 6), the heat sink 13 is pressed against and
fixed to the surface on an opposite side to the surface of the DMD
board 11 on which the socket 11a is provided, by the fixing member
14.
[0076] Hereinafter, the operation of fixing the lighting bracket 26
of the light modulator 10 will be described. First, the light
modulator 10 is positioned at the lighting bracket 26 so that the
DMD 12 faces the opening surface of the irradiating through-hole
26d provided on the lower surface of the lighting bracket 26 of the
illumination unit 20 illustrated in FIG. 6. Next, the screw is
inserted from the lower side of FIG. 6 so as to pass through a
through-hole (not illustrated) provided on the fixing portion 14a
and the through-hole 15 of the DMD board 11. Moreover, by screwing
the screw into the screw hole provided on the lower surface of a
screw stopper 263 (see FIG. 4) provided in the lighting bracket 26,
the light modulator 10 is fixed to the lighting bracket 26.
Furthermore, when screwing the screw to the screw stopper 263
provided in the lighting bracket 26, the pressing portion 14b
presses the heat sink 13 against the DMD board side. Thus, the heat
sink 13 is pressed against and fixed to the surface of an opposite
side to the surface of the DMD board 11 on which the socket 11a is
provided, by the fixing member 14.
[0077] In this way, the light modulator 10 is fixed to the lighting
bracket 26, and three legs 29 illustrated in FIG. 6 also support
the weight of the light modulator 10.
[0078] On the image generation surface of the DMD 12, a plurality
of movable micro mirrors is arranged in a grid shape. Each micro
mirror is able to slope the mirror surface around a torsion axis at
a predetermined angle and is able to have two states of "ON" and
"OFF". When the micro mirror is in the state of "ON", as
illustrated by an arrow L2 in FIG. 8, the micro mirror reflects
light from the light source 61 toward the first optical system 70
(see FIG. 3). When the micro mirror is in the state of "OFF", the
micro mirror reflects light from the light source 61 toward the OFF
light plate 27 held on the side surface of the lighting bracket 26
illustrated in FIG. 7 (see the arrow L1 of FIG. 8). Therefore, by
individually driving each mirror, it is possible to control the
projection of light for each pixel of the image data, thereby
generating the image.
[0079] Light reflected toward the OFF light plate 27 (not
illustrated) is absorbed in the form of heat and is cooled by the
flow of the outdoor air.
[0080] FIG. 10 is a perspective view illustrating a second optical
system included in the second projection optical system 40,
together with the projection lens 31, the illumination unit 20, and
the light modulator 10. As illustrated in FIG. 10, the second
projection optical system 40 is provided with a folding mirror 41
forming the second optical system, and a curved mirror 42 having a
concave shape. The surface that reflects light of the curved mirror
42 can have a spherical shape, a rotationally symmetric aspherical
surface shape, a free curved surface shape or the like.
[0081] FIG. 11 is a perspective view illustrating the second
projection optical system 40, together with the first projection
optical system 30, the illumination unit 20, and the light
modulator 10. As illustrated in FIG. 11, the second projection
optical system 40 is also provided with a dust-proof glass 51 that
transmits the light image reflected from the curved mirror 42 and
protects the optical system components in the apparatus from dust.
In addition, symbol L in the FIG. 11 indicates radiated light from
the light source.
[0082] The second projection optical system 40 has a mirror bracket
43 that holds the folding mirror 41 and the dust-proof glass 51.
Furthermore, the second projection optical system 40 has a free
mirror bracket 44 configured to hold the curved mirror 42, and a
mirror mount 45 to which the mirror bracket 43 and the free mirror
bracket 44 are attached.
[0083] The mirror mount 45 has a box-like shape, the upper surface,
the lower surface, and the back side thereof in the X-direction in
the drawings are opened, and the mirror mount 45 is in the form of
a substantially U-shape when viewed from above. Edges extending in
the X-direction in each of the front side and the back side in the
Z-direction of the upper opening of the mirror mount 45 are formed
of a slope, and a parallel portion. The slope is sloped so as to
rise toward the back side in the X-direction from the front side
end in the X-direction in the drawings. The parallel portion is
parallel to the X-direction in the drawings. In addition, the slope
is located on the front side in the X-direction in the drawings
from the parallel portion. Furthermore, edges extending in the
Z-direction on the front side in the X-direction of the drawings of
the upper opening of the mirror mount 45 are parallel to the
Z-direction in the drawings.
[0084] The mirror bracket 43 is attached to the top of the mirror
mount 45. The mirror bracket 43 has a sloped face 43a that is
sloped so as to rise toward the back side in the X-direction from
the front side end in the X-direction in the drawings coming into
contact with the slope of the upper opening edge of the mirror
mount 45. Furthermore, the mirror bracket 43 also has a parallel
surface 43b parallel to the X direction that comes into contact
with the parallel portion of the upper opening edge of the mirror
mount 45. The sloped face 43a and the parallel surface 43b have the
opening, respectively, the folding mirror 41 is held so as to close
the opening of the sloped face 43a, and the dust-proof glass 51 is
held so as to close the opening of the parallel surface 43b.
[0085] Both ends in the Z-direction of the folding mirror 41 are
pressed against the sloped face 43a of the mirror bracket 43 by a
mirror pressing member 46 having a flat spring shape, and thus, the
folding mirror 41 is positioned and held on the sloped face 43a of
the mirror bracket 43. One end in the Z-direction of the folding
mirror 41 is fixed by two mirror pressing members 46, and the other
end thereof is fixed by one mirror pressing member 46.
[0086] Both ends in the Z-direction of the dust-proof glass 51 are
pressed against the parallel surface 43b of the mirror bracket 43
by a glass pressing member 47 having the flat spring shape, and
thus, the dust-proof glass 51 is positioned and fixed to the mirror
bracket 43. The dust-proof glass 51 is held by the one glass
pressing member 47 at each of both ends in the Z-direction.
[0087] The free mirror bracket 44 configured to hold the curved
mirror 42 has arms 44a sloped so as to descend toward the front
side from the back side in the X-direction of the drawings, on the
front side and the back side in the Z-axis direction. Furthermore,
the free mirror bracket 44 has a connector 44b that connects the
two arms 44a at the top of the arms 44a. The arms 44a of the free
mirror bracket 44 are attached to the mirror mount 45 so that the
curved mirror 42 covers the opening of the back side in the
X-direction in the drawings of the mirror mount 45.
[0088] At the upper end of the curved mirror 42, a substantially
center of an end at the side of the dust-proof glass 51 is pressed
against the connector 44b of the free mirror bracket 44 by a free
mirror pressing member 49 having the flat spring shape.
Furthermore, both ends in the Z-axis direction in the drawings of
the first optical system side of the curved mirror are fixed to the
arms 44a of the free mirror bracket 44 by the screws.
[0089] The second projection optical system 40 is loaded and fixed
to the lens holder 32 of the first projection optical system 30.
Specifically, a lower surface 451 facing the upper surface of the
lens holder 32 is provided below the mirror mount 45. Tubular screw
stoppers 45a1 to 45a3 for being screwed to the first projection
optical system 30 are formed at four positions of the lower surface
451 (the screw stoppers 45a1 and 45a2 are illustrated in FIG. 11,
the screw stopper 45a3 is illustrated in FIG. 6, and the remaining
screw stoppers are not illustrated). The second projection optical
system 40 is screwed to the first projection optical system 30, by
allowing the screws 48 to pass through screw through-holes provided
in the lens holder 32 of the first projection optical system 30,
and by screwing the screws 48 to the screw stoppers 45a1 to
45a3.
[0090] When the second projection optical system 40 is loaded and
fixed to the lens holder 32 of the first projection optical system
30, as illustrated in FIG. 7, a portion above the lens holder 32 of
the projection lens 31 is housed in the mirror mount 45 of the
second projection optical system 40. Furthermore, when the second
projection optical system 40 is loaded and fixed to the lens holder
32, a gap is present between the curved mirror 42 and the lens
holder 32, and the idler gear 35 (see FIG. 7) enters the gap.
[0091] FIG. 12 is a perspective view illustrating the optical path
from the first optical system 70 to the projection plane 2
(screen).
[0092] Optical flux transmitted through the projection lens 31
constituting the first optical system 70 forms a conjugated
intermediate image on the image generated in the DMD 12 between the
folding mirror 41 and the curved mirror 42. This intermediate image
is imaged as a curved surface image between the folding mirror 41
and the curved mirror 42. Next, the diverging optical flux after
imaging the intermediate image is incident on the curved mirror 42
having the concave shape, is converted into a convergent optical
flux, converts the intermediate image into "further expanded image"
by the curved mirror 42, and projects the image onto the projection
plane 2.
[0093] Thus, the projection optical system is constituted by the
first optical system 70 and the second optical system, and the
intermediate image is formed between the first optical system 70
and the curved mirror 42 of the second optical system and is
expanded and projected by the curved mirror 42, thereby being able
to shorten the projection distance, and to use the projection
optical system in a small conference room or the like.
[0094] Furthermore, as illustrated in FIG. 12, the first projection
optical system 30 and the second projection optical system 40 are
loaded and fixed to the lighting bracket 26. The light modulator 10
is also fixed. Thus, the legs 29 of the lighting bracket 26 are
fixed to the base member 53 so as to support the weight of the
first projection optical system 30, the second projection optical
system 40, and the light modulator 10.
[0095] FIG. 13 is a perspective view illustrating an installation
surface side of the projector 1.
[0096] As illustrated in FIG. 13, an opening and closing cover 54
is provided in the base member 53 that forms the lower surface of
the projector 1, and a rotary operation unit 54a is provided in the
opening and closing cover 54. When rotating the rotary operation
unit 54a, fixing between the opening and closing cover 54 and the
apparatus main body is released, and the opening and closing cover
54 can be detached from the apparatus main body. Furthermore, at
the position of the base member 53 that faces the DMD 12, a first
intake duct 92 for cooling the DMD is provided.
[0097] FIG. 14 is a schematic view illustrating an arrangement
relation of each part in the apparatus.
[0098] As illustrated in FIG. 14, the light modulator 10, the
illumination unit 20, the first projection optical system 30, and
the second projection optical system 40 are stacked and disposed in
the Y-direction which is the minor axis direction of the projection
plane. The light source unit 60 is disposed in the Z-direction that
is the major axis direction of the projection plane with respect to
the stack in which the light modulator 10, the illumination unit
20, the first projection optical system 30, and the second
projection optical system 40 are stacked. Thus, in this embodiment,
the light modulator 10, the illumination unit 20, the first
projection optical system 30, the second projection optical system
40, and the light source unit are arranged side by side in the
Y-direction or the Z-direction that is a direction parallel to the
projection image and the projection plane 2. More specifically, the
light source unit 60 is connected to the image forming unit 101 in
a direction perpendicular to the direction in which the image
forming unit 101 formed by the light modulator 10 and the
illumination unit 20, and the projection optical system 102 formed
by the first projection optical system 30 and the second projection
optical system 40 are stacked. Furthermore, the image forming unit
101 and the light source unit 60 are disposed on the same straight
line parallel to the base member 53. Furthermore, the image forming
unit 101 and the projection optical system 102 are disposed on the
same straight line perpendicular to the base member 53, and the
image forming unit 101 and the projection optical system 102 are
disposed from the base member 53 side in this order. This can
suppress the installation space of the apparatus from being taken
in the direction perpendicular to the plane of the projection image
that is projected onto the projection plane 2. Thus, it is possible
to suppress the apparatus from interfering with the arrangement of
tables and chairs even in a narrow room, when the image projector
is used by being placed on the table or the like.
[0099] FIG. 15 is a diagram illustrating an internal configuration
of the projector 1, and FIG. 16 is an explanatory view illustrating
the flow of air in the projector. FIGS. 15 and 16 are schematic
views illustrating the projector 1 from the direction perpendicular
to the projection plane 2 (X-direction).
[0100] As illustrated FIGS. 15 and 16, a second intake duct 84
opened for taking air outside the apparatus into the projector 1 is
provided on one side (left side in FIGS. 15 and 16) of the side
surfaces of the projector 1. An intake fan is not disposed in the
second intake duct 84. Furthermore, an exhaust duct 85 opened to
exhaust the air inside the projector 1 is provided on the other
side (right side in FIGS. 15 and 16) of the side surface of the
projector 1. Furthermore, an exhaust fan 86 is provided to face the
exhaust duct 85.
[0101] Parts of the exhaust duct 85 and the second intake duct 84
are provided between the light source unit 60 and the operation
unit 83, when the projector 1 is viewed from the direction
perpendicular to the projection plane 2 (X-direction). Thus, the
air outside the apparatus taken from the second intake duct 84 goes
around the gap between the lower surface of the curved mirror 42
illustrated in FIG. 6 and the lens holder 32, and the Z-Y plane of
the mirror mount 45 of the second projection optical system 40 and
the back surface of the curved mirror 42. Moreover, the air moves
toward the exhaust duct 85 while flowing along the back surface of
the mirror mount 45 and the curved mirror 42. Furthermore, a part
of the air outside the apparatus taken from the second intake duct
84 is further sucked to the light source blower 95 in the housing,
and flows to the light source unit 60. A power supply device 80
placed on the top of the light source unit 60 has a shape in which
the U-shaped light source unit 60 side is opened by the arrangement
of the three substrates, when viewed from the Z-direction of the
drawings.
[0102] By providing the parts of the exhaust duct 85 and the second
intake duct 84 so as to be located between the light source unit 60
and the operation unit 83 when the projector 1 is viewed from the
direction perpendicular to the projection plane 2 (X-direction), it
is possible to obtain the following effects. That is, there is an
effect in which it is possible to generate the airflow discharged
from the exhaust duct 85 through between the light source unit 60
and the operation unit 83.
[0103] Furthermore, the light source blower 95 is disposed at a
position at which the air around the color motor 21a (see FIG. 6)
for rotationally moving the color wheel 21 of the illumination unit
20 can be sucked. Thus, it is possible to cool the color motor 21a
by the airflow generated by suction of the light source blower
95.
[0104] As illustrated in FIG. 17, air sucked by the light source
blower 95 flows in the light source air supply port 64b (see FIG.
5) of the holder 64 through the light source duct 96. Furthermore,
a part of the air flowing in the light source duct 96 flows between
the light source housing 97 and the exterior cover 59 from the
opening 96a formed on the surface of the light source duct 96
opposite to the exterior cover 59 (see FIG. 13).
[0105] The air flowing between the light source housing 97 and the
exterior cover 59 from the opening 96a of the light source duct 96
cools the light source housing 97 and the exterior cover 59, and
then is discharged from the exhaust duct 85 by the exhaust fan
86.
[0106] Furthermore, after the air flowing into the light source air
supply port 64b flows into the light source 61 to cool the light
source 61, the air is exhausted from the light source exhaust duct
64c provided on the upper surface of the holder 64. The air
exhausted from the light source exhaust duct 64c is exhausted to
the space surrounded by the power supply device 80 from the opening
of the upper surface of the light source housing 97 through the
fluid guide 87. Thereafter, after the air is mixed with a
low-temperature air going around the second projection optical
system 40 and flowing into an enclosed space of the power supply
device 80, the mixed air is discharged from the exhaust duct 85 by
the exhaust fan 86. In this way, since the high-temperature air
exhausted from the light source exhaust duct 64c is mixed with the
air outside the apparatus taken from the second intake duct 84 and
then is exhausted, it is possible to suppress the air exhausted
from the exhaust duct 85 from becoming a high temperature.
[0107] Still referring to FIG. 17, the fluid guide 87 is formed in
step-wise shape. With this configuration, the light from the light
source is not reflected in the direction toward the exhaust fan
86.
[0108] In addition, it is preferred that the operation unit 83
operated by a user be provided on the upper surface of the
apparatus so as to be easily operated by the user. However, in this
embodiment, since the dust-proof glass 51 for projecting the image
onto the projection plane 2 is provided on the upper surface of the
projector 1, the operation unit 83 is provided at a position that
overlaps the light source 61 when the projector is viewed from the
Y-direction.
[0109] In this embodiment, since the air becoming the high
temperature by cooling the light source 61 is exhausted toward the
exhaust duct 85, by the airflow flowing toward the exhaust duct 85
from the second intake duct 84 between the light source unit 60 and
the operation unit 83, it is possible to suppress the
high-temperature air from moving to the operation unit 83. Thus, it
is possible to suppress the temperature of the operation unit 83
from rising, by the air becoming a high temperature by cooling the
light source 61. Furthermore, a part of the air going around the
second projection optical system 40 from the second intake duct 84
and flowing toward the exhaust duct 85 passes through the right
under the operation unit 83 to cool the operation unit 83. This can
also suppress an increase in temperature of the operation unit
83.
[0110] Furthermore, the air outside the apparatus is sucked from
the power source intake duct 56 provided on the base member 53
illustrated in FIG. 13 by the suction of the exhaust fan 86. On the
back side in the X-direction in the drawings from the light source
housing 97, a ballast substrate (not illustrated) for supplying
stable power (current) to the light source 61 is disposed. The air
outside the apparatus absorbed from the power source intake duct 56
cools the ballast substrate, while moving upward between the light
source housing 97 and the ballast substrate (not illustrated).
Thereafter, after the air flows into the space surrounded by the
power supply device 80 disposed above the ballast substrate, the
air is exhausted from the exhaust duct 85 by the exhaust fan
86.
[0111] Furthermore, on a left lower side of FIG. 16 of the
apparatus main body, a cooling unit 120 that cools the heat sink 13
of the light modulator 10, the light source bracket 62 of the light
source unit 60 or the like is disposed. The cooling unit 120 has an
intake blower 91, and a horizontal duct 93. Furthermore, at a
position of the base member 53 facing the intake blower 91, the
first intake duct 92 is provided. With this configuration, there is
provided a state in which the intake blower 91 is disposed in the
first intake duct 92.
[0112] As illustrated in FIG. 18, the intake blower 91 is a
double-sided intake sirocco fan. The intake blower 91 is attached
to the light modulator 10 such that the base member side blower
intake duct 91a of the intake blower 91 faces the first intake duct
92 provided in the base member 53 as an opposite surface facing the
DMD 12 of the housing of the projector. In addition, the opposite
surface of the base member side blower intake duct 91a of the
intake blower 91 is also an intake duct, but a quantity of intake
of the base member side blower intake duct 91a is high. The heat
sink 13 is formed by a first fin 13a having a predetermined fin
height, and a second fin 13b having a fin height higher than that
of the first fin 13a. The intake blower 91 is attached to the first
fin 13a such that the blower exhaust duct 91b of the intake blower
91 faces the second fin 13b of the heat sink 13. By using the
intake blower 91 as a double-sided intake sirocco fan, the first
fin 13a of the heat sink 13 can be efficiently cooled.
[0113] As illustrated in FIG. 16, in the horizontal duct 93, the
upper surface and lower surface are partially opened, and the
horizontal duct 93 is fixed to the base member 53 of the projector
1 such that the opening of the lower surface faces the first intake
duct 92 provided in the base member 53. Furthermore, the light
modulator 10 is disposed on the horizontal duct 93 such that the
heat sink 13 of the light modulator 10 and the intake blower 91
attached to the light modulator 10 pass through the opening of the
upper surface of the horizontal duct.
[0114] The intake blower 91 sucks the air outside the apparatus by
the base member side blower intake duct 91a via the first intake
duct 92, and exhausts the air outside the apparatus sucked by the
intake blower 91 toward the second fin 13b of the heat sink 13 from
the blower exhaust duct 91b. Thus, the second fin 13b of the heat
sink 13 is air-cooled. The DMD 12 can be efficiently cooled by
air-cooling of the second fin 13b of the heat sink 13, thereby
suppressing the DMD 12 from becoming a high temperature.
[0115] As illustrated in FIG. 16, the flow is generated by the
intake blower 91, and the air passed through the heat sink 13 moves
in the horizontal duct 93 and flows into the passage 65 or the
opening 65a provided in the light source bracket 62 of the light
source unit 60 illustrated in FIG. 5. The air flowing into the
opening 65a flows between the opening and closing cover 54 and the
light source bracket 62 to cool the opening and closing cover
54.
[0116] The air flowing into the passage 65 cools the light source
bracket 62, and then flows into the portion on the opposite side to
the emission side of the light source 61 to cool the side opposite
to the reflection surface of the reflector of the light source 61,
thereby cooling the reflector of the light source 61. Thus, the air
passing through the passage 65 absorbs heat of both the light
source bracket 62 and the light source 61. The air passed through
the vicinity of the reflector passes through the exhaust duct 94
that guides the air from the height of the light source bracket 62
to the height near the bottom of the exhaust fan 86. Thereafter,
the air joins the air exhausted from the light source exhaust duct
64C. The mixed air is then discharged from the exhaust duct 85
through the fluid guide 87 by the exhaust fan 86. The air flowing
into between the opening and closing cover 54 and the light source
bracket 62 through the opening 65a cools the opening and closing
cover 54, moves in the apparatus, and is discharged from the
exhaust duct 85 by the exhaust fan 86. Accordingly, the flow path
of air from the first intake duct 92 to the exhaust duct 85 is away
from spaces between the lower surface of the curved mirror 42 and
the lens holder 32.
[0117] Before explaining the flow of air in the image projection
apparatus 1 of the present embodiment, the flow of air in the
background image projection apparatus is described as a comparative
example.
[0118] FIG. 25 is a perspective view illustrating the flow of air
above a light source housing of the background image projection
apparatus described in JP-2013-109042 A, and FIG. 20 is a
cross-sectional view thereof.
[0119] The background image projection apparatus is provided with
an intake duct that takes air from the outside into an apparatus
main body, an exhaust duct 85 that discharges the air from the
apparatus main body, and an exhaust fan 86 that generates the flow
of air from the intake duct toward the exhaust duct 85.
[0120] As illustrated FIGS. 25 and 26, a cooling air C taken from
the intake duct hits against a wall 98a of a duct 98 provided with
a fluid guide 87, is dispersed in all directions, and flows toward
the exhaust fan 86. As illustrated in FIG. 25, the cooling air C
flowing onto the upper surface of the duct 98 cools the power
supply device 80, and then joins air H subsequent to cooling the
light source that is raised along the fluid guide 87 in front of
the exhaust fan 86, in particular, at the merging area G indicated
by a chain line in FIG. 25. Moreover, the air is exhausted from the
exhaust duct 85 by the exhaust fan 86. In this example, the light
source unit 60 in which the temperature of the valve reaches near
1000.degree. C. has a high rated temperature, compared to that of
the power supply device 80 in which elements having the rated
temperature of 105.degree. C. or less are aligned. Accordingly, the
cooling air C, even after cooling the power supply device 80, has a
sufficiently low temperature than that of the air H subsequent to
cooling the light source.
[0121] Furthermore, since the cooling air C flows through the
narrow space enclosed by the upper surface of the duct 98 and the
power supply device 80, the cooling air C increases in the flow
velocity while flowing into the merging area G. This is clear from
the fact that the flow rate of fluid passing through a certain
cross-section is calculated by the product of the flow velocity and
the cross-sectional area. Bernoulli's theorem shows that the more
the flow velocity is, the lower the pressure is. Therefore, by
allowing the cooling air to flow through the narrow flow path
between the upper surface of the duct 98 and the power supply
device 80, the flow velocity of the cooling air increases at the
moment of passing through the flow path, and as a result, the
pressure drop occurs from the Bernoulli's theorem.
[0122] Meanwhile, since the apparatus has a configuration in which
the flow path gradually widens in the process of flowing along the
fluid guide 87, the air H subsequent to cooling the light source
flows into the merging area G while the flow velocity thereof
decreases. As a result, a flow velocity difference occurs between
the cooling air C and the air H subsequent to cooling the light
source at the merging area G. As a result of the occurrence of
difference in the flow velocity, the air H subsequent to cooling
the light source having the small flow velocity is naturally drawn
to the cooling air C having the large flow velocity with a lower
pressure than the air H subsequent to cooling the light source.
Thus, the air H subsequent to cooling the light source flows toward
the exhaust fan 86 along the flow of the cooling air C. As a
result, the cooling air C and the air H subsequent to cooling the
light source are not sufficiently mixed with each other, become two
air layers of a cooling air layer and an air layer subsequent to
cooling the light source, and flow toward the exhaust fan 86.
[0123] As illustrated in FIG. 25, in the background image
projection apparatus, the leading end of the exhaust fan 86 side of
the fluid guide 87 is located above the center of rotation of the
exhaust fan 86. Therefore, the cooling air C having the high flow
velocity joins the air subsequent to cooling the light source at a
position above the rotary shaft 86a of the exhaust fan 86.
Furthermore, since the cooling air C hits against the wall 98a of
the duct 98 and disperses in all directions, the flow rate of the
cooling air C flowing between the upper surface of the duct 98 and
the space surrounded by the power supply device 80 decreases. As a
result, the cooling air C flows to the exhaust fan 86 so as to be
lifted up by ascending airflow of the air H subsequent to cooling
the light source. As a result, the two air layers of the cooling
air layer and the air layer subsequent to cooling the light source
flow upward from the rotary shaft 86a of the exhaust fan 86.
Moreover, the air of the two layers of the cooling air layer and
the air layer subsequent to cooling the light source is cut by a
blade 86b of the exhaust fan 86, and then is exhausted to the
outside of the apparatus so as to be pushed into the exhaust duct
85. The blade 86b of the exhaust fan 86 has a main function of
cutting and pushing the air, and thus, the two air layers of the
cooling air layer and the air layer subsequent to cooling the light
source are hardly stirred by the blade 86b. Thus, in the background
image projection apparatus, the cooling air layer and the air layer
subsequent to cooling the light source are not sufficiently mixed
with each other, and two air layers of the cooling air layer and
the air layer subsequent to cooling the light source are caused and
exhausted to the outside of the apparatus. As a result, there has
been a temperature distribution in which some of the air exhausted
from the exhaust duct is at a relatively high temperature, and the
other thereof is at a relatively low temperature.
[0124] The above-described technique of mixing the cooling air with
the air subsequent to cooling the light source, before exhausting,
is applied due to the fact that it is not possible to reduce
thermal energy itself held by the air subsequent to cooling the
light source to be exhausted. Thermal energy is generated by
conversion of optical energy emitted from the light source, and
there is a possibility that a decrease in thermal energy itself
leads to a decrease in optical energy. Since the decrease in the
optical energy may lower an amount of light of the projector, the
value of the product is lowered. Therefore, when lowering the
temperature of the exhausted air, the magnitude of thermal energy
itself does not change, and only the temperature needs to be
lowered. As the most effective unit that lowers only the exhaust
temperature without changing the magnitude of thermal energy itself
of the light source, there is a method of mixing the
low-temperature air in the apparatus with the high-temperature air
subsequent to cooling the light source to obtain a uniform
temperature of the exhaust air. This can reduce the temperature of
the exhaust gas without lowering the thermal energy, and does not
affect the specification of the product itself, such as brightness.
However, in the conventional configuration, the low-temperature air
and the high-temperature air had not been mixed with each other
well, resulting in non-uniformity such that the exhaust air may
have contained the hot spots.
[0125] In view of the above, one aspect of an example embodiment of
the present invention is to provide an image projection apparatus
that can obtain a uniform temperature distribution of air to be
discharged from the outside of the apparatus.
[0126] More specifically, in the following embodiment, the two air
layers of the cooling air layer and the air layer subsequent to
cooling the light source are caused to collide with the rotary
shaft 86a of the exhaust fan 86, and are exhausted by stirring the
air layers by the rotary shaft 86a of the exhaust fan.
[0127] FIG. 19 is a cross-sectional view illustrating the flow of
air above the light source housing 97 of this embodiment, and FIG.
20 is a view as viewed from a direction of an arrow "a" in FIG.
19.
[0128] As illustrated in FIG. 19, in this embodiment, the apparatus
is configured so that the leading end of the exhaust fan 86 side of
the fluid guide 87 is provided at a position facing the center of
rotation of the exhaust fan 86, and the cooling air C is directed
to the rotary shaft 86a of the exhaust fan 86. Furthermore, in this
embodiment, the apparatus is configured so that the duct 98 (See
FIG. 26) is not provided and only the fluid guide 87 is provided.
The cooling air C is guided by the surface of the fluid guide 87
that is opposite to the surface that guides the air H subsequent to
cooling the light source. That is, in this embodiment, the
apparatus is configured so that the flow path of the cooling air
becomes gradually narrow toward the merging area G.
[0129] In this example, the rotary shaft 86a not only includes a
rotary axis defined by the center of rotation of the exhaust fan
96, but also includes surroundings of the rotary axis such as any
portion having the rotary axis therein, for example, a surface
having the rotary axis in its center.
[0130] With such a configuration, the cooling air C (air outside
the apparatus) drawn from the second intake duct 84 and going
around the second projection optical system 40 hits against the
surface of the fluid guide 87 on the opposite side to the guide
surface of the air H subsequent to cooling the light source. As
illustrated in FIG. 19, the fluid guide 87 has a sloped face that
is sloped, such that the upper end portion thereof is located near
the position where the exhaust fan 86 is disposed. The cooling air
C that hits against the fluid guide 87 is guided by the fluid guide
87 and moves upward. Since the flow path becomes gradually narrow
toward the merging area G, the flow velocity of the cooling air
moving to the merging area G while being guided by the fluid guide
87 becomes gradually higher. In this embodiment, the
cross-sectional area of the space surrounded by the leading end of
the fluid guide 87 and the power supply device 80 is substantially
the same as the configuration illustrated in FIG. 26. Thus, the
flow velocity of the cooling air C flowing to the merging area G
becomes the flow velocity that is substantially the same as the
configuration illustrated in FIG. 26.
[0131] In this embodiment, since the leading end of the exhaust fan
86 side of the fluid guide 87 is provided at a position facing the
center of rotation of the exhaust fan 86, the cooling air flows
into the merging area G, directing toward the rotary shaft 86a of
the exhaust fan 86. As described above, the cooling air C flows
into the merging area G while accelerating the flow velocity.
[0132] In this embodiment, since the apparatus has a configuration
in which the flow path of the cooling air C becomes gradually
narrow toward the merging area G, compared to the configuration in
which the flow path becomes rapidly narrow as illustrated in FIG.
26, the flow rate of the cooling air C that flows to the merging
area G increases. Therefore, the air in the two layers of the
cooling air C and the air H subsequent to cooling the light source
joined at the merging area G flows toward the rotary shaft 86a of
the exhaust fan 86, without being raised by the ascending airflow
of the air H subsequent to cooling the light source. Moreover, the
air in the two layers of the cooling air C and the air H subsequent
to cooling the light source collides with the rotary shaft 86a of
the exhaust fan 86.
[0133] As the air in the two layers of the cooling air C and the
air H subsequent to cooling the light source collides with the
rotary shaft 86a of the exhaust fan 86, the air is disturbed, and
with rotation of the rotary shaft 86a, the air is instantaneously
stirred. After being mixed in front of the exhaust fan 86, the air
in the two layers of the cooling air C and the air H subsequent to
cooling the light source is exhausted to the outside of the
apparatus by the exhaust fan 86. Further, in this example, the air
in the two layers of the cooling air C and the air H subsequent to
cooling the light source has a certain length in a direction
perpendicular to the sheet surface of FIG. 19, such that the air of
the two layers has a portion that does not collide with the rotary
shaft 86a of the exhaust fan 86. However, by the turbulence of the
air colliding with the rotary shaft 86a and the stirring action of
the rotary shaft 86a, the air that does not collide with the rotary
shaft 86a is also disturbed in front of the exhaust fan 86. As a
result, in the air that does not collide with the rotary shaft 86a,
the cooling air C and the air H subsequent to cooling the light
source are mixed in front of the exhaust fan 86. This suppresses
the air from being exhausted to the outside of the apparatus in the
state of two layers of the cooling air layer and the air layer
subsequent to cooling the light source, and further suppresses the
high-temperature hot spots from locally occurring in the exhaust
wind. This improves uniformity in temperature in the exhaust wind
while suppressing an occurrence of a high temperature location in a
part of the grid-like exhaust duct 85.
[0134] As described above, in this embodiment, by allowing the air
in two layers of the cooling air C and the air H subsequent to
cooling the light source to collide with the rotary shaft 86a of
the exhaust fan 86, thereby stirring the air by the rotation of the
rotary shaft 86a, the cooling air C is actively mixed with the air
H subsequent to cooling the light source.
[0135] Furthermore, in this embodiment, the cooling air C and the
air H subsequent to cooling the light source are mixed with each
other by the rotary shaft 86a of the exhaust fan 86. Accordingly,
there is no need to provide a new stirring mechanism, and there is
no need to provide a mixing region in the housing. Thus, there is
merit even in a design of a compact projector.
[0136] Furthermore, in this embodiment, a distance L (FIG. 19) from
the rotary shaft 86a of the exhaust fan 86 to the leading end of
the fluid guide 87 is set to about 30 mm. When the distance L is
too short, the air H subsequent to cooling the light source is not
sufficiently attracted to the cooling air C, such that the air H
subsequent to cooling the light source is exhausted from below the
rotary shaft 86a. As a result, the exhaust wind of the lower side
of the rotary shaft 86a becomes a high temperature. Meanwhile, when
the distance L is too long, there is a high risk that the cooling
air C is not directed toward the rotary shaft 86a. By setting the
distance L from the rotary shaft 86a of the exhaust fan 86 to the
leading end of the fluid guide 87 to about 30 mm, it can
satisfactorily attract the air H subsequent to cooling the light
source to the cooling air C, while allowing the air in the two
layers of the layer of the air H subsequent to cooling the light
source and the layer of the cooling air C to reliably hit against
the rotary shaft 86a.
[0137] In this example, the exhaust fan 86 has the rotary shaft 86a
of about 37 mm in diameter, two blades 86b each of about 72 mm in
diameter, and airflow rate is about 0.825 cubic meters/min. The
airflow rate for the light source blower 95 is about 0.1 cubic
meters/min. The airflow rate for the intake blower 91 is about
0.147 cubic meters/min.
[0138] Next, modified examples of the present embodiment will be
described.
First Modified Example
[0139] FIG. 21 is a cross-sectional view illustrating the flow of
air above a light source housing 97 of a first modified example,
and FIG. 22 is a perspective view illustrating an exhaust fan 86 of
the first modified example.
[0140] As illustrated FIGS. 21 and 22, in the first modified
example, a stirring member 180 is provided on the rotary shaft 86a
of the exhaust fan 86. As illustrated in FIG. 22, the stirring
member 180 has a configuration in which blades 181 are provided
around a hemispherical projection 182 in a rotational direction at
equal intervals.
[0141] In the first modified example, as illustrated in FIG. 25,
the air in two layers of the cooling air C and the air H subsequent
to cooling the light source flowing toward the rotary shaft 86a is
stirred by the stirring member 180. With this configuration, the
cooling air C is actively mixed with the air H subsequent to
cooling the light source. Accordingly, the air, or the exhaust
wind, to be exhausted from the exhaust duct 85 has uniform
temperature, while suppressing the occurrence of the locally hot
spots.
[0142] Furthermore, the stirring member 180 is provided with the
hemispherical projection 182. Thus, the air in two layers of the
cooling air C and the air H subsequent to cooling the light source
is diffused by the projection 182. This suppresses the
high-temperature air H subsequent to cooling the light source from
being exhausted to the outside of the apparatus from one location
of the exhaust duct 85 by being diffused, and the occurrence of the
locally hot spots can be further suppressed.
[0143] Furthermore, the stirring member 180 may have a prismatic
shape, as illustrated in FIG. 23. In such a prismatic member, only
by attaching the prismatic stirring member 180 to the rotary shaft
86a of the exhaust fan, a stirring effect of the air in two layers
of the cooling air C and the air H subsequent to cooling the light
source due to the stirring member 180 can be confirmed.
[0144] Furthermore, as illustrated FIGS. 24A and 24B, the prismatic
stirring member 180 may be provided at a position that is deviated
from the center of rotation of the exhaust fan 86. Thus, by
providing the stirring member 180 at a position deviated from the
center of rotation of the exhaust fan 86, the stirring effect can
be enhanced.
[0145] In another example, the flow velocity of the air H
subsequent to cooling the light source may be set to be higher than
the flow velocity of the cooling air C, and the air H subsequent to
cooling the light source may flow toward the rotary shaft 86a of
the exhaust fan 86. In the case of such a configuration, the
cooling air C is attracted to the air H subsequent to cooling the
light source and flows to the rotary shaft 86a along the air H
subsequent to cooling the light source, thus allowing the air in
two layers of the cooling air C and the air H subsequent to cooling
the light source to flow through the rotary shaft 86a of the
exhaust fan 86.
[0146] Numerous additional modifications and variations are
possible in light of the above teachings. It is therefore to be
understood that within the scope of the appended claims, the
disclosure of the present invention may be practiced otherwise than
as specifically described herein. For example, elements and/or
features of different illustrative embodiments may be combined with
each other and/or substituted for each other within the scope of
this disclosure and appended claims.
[0147] According to one aspect, in the image projection apparatus
such as the projector 1 that is provided with a light source 61,
the air H subsequent to cooling the light source heated by the
light source 61, joins the cooling air C having a lower temperature
than that of the air H, at the merging area G, before being
exhausted to the outside of the apparatus.
[0148] The air flows to the merging area G such that the flow
velocity difference occurs between the air H and the air C at the
merging area G, and the air having the higher flow velocity flows
to the rotary shaft of the exhaust fan 86.
[0149] As is evident from Bernoulli's theorem that is a
conservation side of pressure and flow velocity, the air having the
higher flow velocity flows through the merging area at a lower
pressure than the air having the low flow velocity. As a result,
the air having the low flow velocity is attracted to the air having
the high flow velocity and flows along the air having the high flow
velocity. Furthermore, since the apparatus is configured so that
the air having the high flow velocity flows toward the rotary shaft
of the exhaust fan, the air having the high flow velocity and the
air having the low flow velocity moving along the flow collide with
the rotary shaft of the exhaust fan. That is, the air H heated by
the light source and the air C having the lower temperature than
the air H collide with the rotary shaft of the exhaust fan. By
collision of the heated air and the cooling air with the rotary
shaft, the air is disturbed, and the air that collides by the
rotation of the rotary shaft is stirred. Accordingly, the heated
air can be satisfactorily mixed with the cooling air in front of
the exhaust fan, and the mixed air can be exhausted to the outside
of the apparatus by the exhaust fan. This helps to obtain a uniform
temperature distribution of the air exhausted to the outside of the
apparatus, thus suppressing the high-temperature air from being
partially exhausted from the exhaust duct.
[0150] In one example, the apparatus is configured so that the flow
path configured to allow the air having the high flow velocity to
flow to the merging area G becomes gradually narrow toward the
merging area G.
[0151] According to one aspect, the flow velocity can be increased
by gradually narrowing the flow path as described in the
embodiment. This can further suppress a decrease in flow rate
flowing into the merging area G.
[0152] In one example, the apparatus is provided with a guide, such
as the fluid guide 87 that gradually narrows the flow path, which
allows the air having the high flow velocity to flow to the merging
area. The flow path further has the downstream end in the flow
direction of air of the guide, which faces the rotary shaft 86a of
the exhaust fan 86.
[0153] With this configuration, the air having the high flow
velocity flows to the rotary shaft 86a.
[0154] Furthermore, according to some examples, the apparatus is
equipped with a stirring unit such as the stirring member 180 that
stirs the air flowing to the rotary shaft 86a.
[0155] For example, as described in the first modified example, it
is possible to actively stir the air including the layer of the
cooling air C flowing to the rotary shaft 86a and the layer of the
air subsequent to cooling the light source, by the stirring member
180. With this configuration, the air is actively mixed to obtain a
further uniform temperature distribution of the air exhausted from
the exhaust duct.
[0156] In one example, the stirring unit such as the stirring
member 180 is provided on the rotary shaft 86a.
[0157] According to one example, by providing the stirring member
180 on the rotary shaft 86a, the stirring member 180 is rotated
with rotation of the exhaust fan 86, thus eliminating a drive
source for rotationally driving the stirring member 180. This can
suppress an increase in the number of components, thus suppressing
an increase in the cost of the apparatus.
[0158] In one example, the stirring unit such as the stirring
member 180 is provided at the center of the rotary shaft of the
exhaust fan 86. With this configuration, the wear of the shaft due
to the axial vibration of the exhaust fan 86 can be suppressed, as
well as suppressing shortening of the life of the exhaust fan
86.
[0159] In one example, the stirring unit such as the stirring
member 180 is a projection that is attached to the position located
at a distance away from the center of the rotary shaft of the
exhaust fan 86. This improves the stirring efficiency, as compared
to the case of providing the projection at the center of the rotary
axis of the exhaust fan 86.
* * * * *