JP2003140260A - Projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector of which optical system can be efficiently cooled and the lamp reflector of the lamp of a light source can be uniformly cooled without making a projector main body larger. SOLUTION: This projector (1) which is a liquid crystal projector where light emitted from the light source (18) is modulated by liquid crystal boards (34, 36 and 38), a DMD or an LCOS and projected from a projection lens (10), is characterized in that it is provided with the light source equipped with the lamp (70) and the lamp reflector (72), a tubular light tunnel (42) arranged on the front side of the lamp reflector and guiding the light emitted from the light source to the projection lens, and a fan (76) for sending an air current in parallel with the optical axis of the light emitted from the light source to the lamp reflector from the back of the lamp reflector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projector, and more particularly to a projector in which an optical system including a lamp and the like is cooled by a fan.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open No. 11-119181 discloses
A cooling structure for a projection type liquid crystal display device (projector) is described. In this projection type liquid crystal display device, an optical system including a light source lamp unit, a liquid crystal panel unit, a color synthesizing optical unit, and the like is arranged in the housing, and air introduced into the housing by a cooling fan is supplied to the housing. The optical system is cooled by distributing it to each unit of the optical system by an air delivery pipe provided inside.
With this configuration, a single fan cools a plurality of units of the optical system.

Further, Japanese Patent Laid-Open No. 11-119342 discloses an image display mechanism and an image display device (projector). In this image display device, an optical system including a reflection type liquid crystal panel to which heat radiation fins are attached, a lamp case, etc. is arranged in the housing, and by driving an exhaust fan attached to the wall surface of the housing, The air in the housing that has been warmed by the optical system is exhausted. When the air pressure inside the housing is lowered by the exhaust air, outside air flows in from an air intake port of the housing provided near the reflective liquid crystal panel. The inflowing outside air cools the reflection type liquid crystal panel to which the heat radiation fins are attached, further cools the lamp case arranged in the middle of the air flow path, and is discharged to the outside of the housing.

[0004]

However, in the projection type liquid crystal display device described in Japanese Patent Laid-Open No. 11-119181, it is necessary to provide an air delivery pipe for cooling the optical system, and the entire projector becomes large. Also, there is a problem that the cost becomes high. In addition, JP-A-1
In the projector described in Japanese Patent Laid-Open No. 1-119342, there is a problem in that it is not possible to intensively cool only the portion that requires cooling, because the cooling air flows directly into the housing.

Further, in the projectors described in JP-A-11-119181 and JP-A-11-119342, since the cooling air is applied to the lamp from the side surface of the lamp reflector, the lamp reflector is used. The temperature of each part becomes uneven. As a result, thermal stress is generated in the lamp reflector, and in the worst case, the lamp bursts. Therefore, an object of the present invention is to provide a projector capable of efficiently cooling an optical system and uniformly cooling a lamp reflector of a lamp of a light source without increasing the size of a projector main body. .

[0006]

In order to solve the above-mentioned problems, the projector of the present invention is a projector in which light emitted from a light source is modulated by a liquid crystal plate, DMD or LCOS and projected from a projection lens. lamp,
And a light source having a lamp reflector, a tubular light tunnel arranged on the front side of the lamp reflector for guiding the light emitted from the light source to the projection lens, and a light source parallel to the optical axis of the light emitted from the light source. And a fan for sending the airflow from the back surface of the lamp reflector to the lamp reflector.

In the present invention thus constructed,
Air is sent to the lamp reflector from the back side by the fan in a direction parallel to the optical axis of the light source. The air sent by the fan forms a uniform air flow around the lamp reflector and cools the lamp reflector. The air that has cooled the lamp reflector flows to the front side of the lamp reflector and cools the light tunnel arranged on the front side of the lamp reflector.

Since the lamp reflector generally has a shape substantially rotationally symmetrical with respect to the optical axis, a substantially uniform air flow is formed around the lamp reflector, and the lamp reflector is cooled uniformly. This can prevent a large thermal stress from being generated in the lamp reflector. Further, since the air that has cooled the lamp reflector also cools the light tunnel, the entire optical system can be efficiently cooled by one fan.

Further, in the projector of the present invention, the light tunnel has an inner wall for forming an optical path for guiding the light from the light source to the projection lens, and an outer wall for forming a passage for cooling air outside the inner wall. The air flow generated by the fan and cooling the lamp reflector may be guided to the passage between the outer wall and the inner wall. In the present invention thus configured, the air flowing around the lamp reflector and cooling the lamp reflector flows into the passage between the inner wall and the outer wall of the light tunnel to cool the light tunnel. Thereby, the light tunnel and the illumination optical system can be cooled more efficiently.

Preferably, the fan is an axial flow fan, and the rotation axis of the axial flow fan is aligned with the optical axis of the light source.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings. 1 is a perspective view showing a housed state of a projector 1 according to an embodiment of the present invention.
FIG. 3 is a perspective view showing a usage state of the projector 1.

A projector 1 according to an embodiment of the present invention
Is an illumination optical system (not shown) serving as a heat source, the projection lens 1
0, a first housing 2 accommodating a power source (not shown), and a second housing 4 accommodating an image processing electronic circuit (not shown) that is a signal processing unit. The second housing is rotatably connected by a hinge component 6.
This hinge component 6 allows the projector 1 to move from the storage state shown in FIG. 1 in which the front surface 2b, which is the lens mounting surface of the first housing, and the front surface 4b of the second housing face each other to the upper surface 2a of the first housing It is configured so that the upper surfaces 4a of the two housings face each other and the first housing is supported on the second housing so that it can be transformed into the use state shown in FIG. A plurality of operation switches 8 are provided on the outer side surface of the first housing. Further, the projection lens 10 and the vent hole 1 for cooling the illumination optical system and the like.
2a and 12b are provided on the front surface 2b of the first housing.

FIG. 3 is a sectional view showing the inside of the first and second casings. As shown in the figure, the first housing 2 includes an illumination optical system 14, an illumination optical system power source 16, a projection lens 10,
Have. The second housing 4 also has an electronic circuit board 56 on which an image processing circuit and the like are mounted, and a DC power supply 58 for operating the circuits of the electronic circuit board 56. The illumination optical system 14 includes a light source 18, a light pipe 20, a polarization conversion element 21, a first condenser lens 22, a second condenser lens 23, a first dichroic mirror 24, and a second dichroic mirror constituting a color separation optical system. A mirror 26,
It has mirrors 28, 30, 32, transmission type liquid crystal plates 34, 36, 38 which are modulation optical systems, and a dichroic prism 40 which is a synthetic optical system. Each of these optical elements includes the first to sixth light tunnels 42, 44, 46, 4
8, 50 and 52, respectively.

Preferably, these light tunnels are
The cross-sectional shape corresponds to the shape of the light to be emitted from the projection lens 10. That is, in the case of emitting light having a cross-sectional shape with an aspect ratio of 4: 3, it is preferable that the cross-sectional shape of the light tunnel be a substantially rectangular shape and the aspect ratio of the rectangle be 4: 3. Further, the light tunnel is preferably made of a material having high thermal conductivity, for example, a metal such as aluminum. Preferably, the inner surface of the light pipe 20 is a light reflecting surface.
Depending on the application, a rod lens may be used instead of the light pipe 20. Furthermore, depending on the application,
The first to sixth light tunnels 42, 44, 46, 48,
The inner surfaces of 50 and 52 may be light reflecting surfaces.

A light pipe 20 is arranged in the light emitting direction of the light source 18, and a polarization conversion element 21 is arranged at the end of the light pipe 20 opposite to the light source 18. The first light tunnel 42 is configured to communicate with the light pipe 20, is emitted from the light source 18, and is connected to the light pipe 20.
And receives the light beam that has passed through the polarization conversion element 21. The condenser lens 2 is provided at the entrance of the first light tunnel 42.
2 is attached. The second light tunnel 44 communicates with the first light tunnel 42, and the first light tunnel 4
The first light tunnel 42 extends at a right angle from the side closer to the tip than the second condenser lens 22. The first dichroic mirror 24 is attached at a branch point between the first light tunnel 42 and the second light tunnel 42 at an angle of 45 ° with respect to the first light tunnel 42. The dichroic mirror 24 is configured to reflect red light, direct it to the second light tunnel 44, and transmit light of other colors.

The third light tunnel 46 communicates with the first light tunnel 42, is parallel to the second light tunnel 44, and is closer to the tip than the second light tunnel 44 is.
It extends at right angles to the first light tunnel 42. The second dichroic mirror 26 is attached at a branch point between the first light tunnel 42 and the third light tunnel 46 at an angle of 45 ° with respect to the first light tunnel 42. The second dichroic mirror 26 is configured to reflect green light, direct the green light to the third light tunnel 46, and transmit light of another color (blue light).

The fourth light tunnel 48 communicates with the first light tunnel 42 and extends parallel to the third light tunnel 46 from the tip of the first light tunnel 42 at a right angle to the first light tunnel 42. . Mirror 28
It is attached to the tip of the first light tunnel 42 at an angle of 45 ° with respect to the first light tunnel 42.
The mirror 28 is configured to direct incident light to the fourth light tunnel 48.

The fifth light tunnel 50 communicates with the second light tunnel 44 and extends parallel to the first light tunnel 42 from the tip of the second light tunnel 44 toward the tip of the third light tunnel 46. The mirror 30 is attached to the tip of the second light tunnel 44 and the second light tunnel 4
It is attached at an angle of 45 ° with respect to 4, and guides the red light reflected by the dichroic mirror 24 toward the fifth light tunnel 50.

Similarly, the sixth light tunnel 52 is
Communicating with the light tunnel 48, the fourth light tunnel 48
From the tip of the first light tunnel 42 toward the tip of the third light tunnel 46. Mirror 3
2 is attached to the tip of the fourth light tunnel 48 at an angle of 45 ° with respect to the fourth light tunnel 48,
The blue light reflected by the mirror 28 is guided toward the sixth light tunnel 52.

The liquid crystal plate 34 for modulating the red light is the fifth
A liquid crystal plate 36 for modulating green light is provided at the tip of the light tunnel 50, and a liquid crystal plate 38 for modulating blue light is provided at the tip of the third light tunnel 46 and a sixth light tunnel 52.
Are arranged at the tip of each. A substantially cubic dichroic prism 40 is arranged at the confluence of the third, fifth and sixth light tunnels. Dichroic prism 4
At 0, a reflecting surface 40r that reflects only red light, which is directed in the direction of the diagonal, and a reflecting surface 40b that reflects only blue light, which is directed in a direction orthogonal to the reflecting surface 40r.
And are provided. As a result, the dichroic prism 40 enters the fifth light tunnel 50 and receives the red light that is modulated by the liquid crystal plate 34, the third light tunnel 46 that receives the green light that is modulated by the liquid crystal plate 36, and the sixth light. The blue light that enters from the light tunnel 52 and is modulated by the liquid crystal plate 38 is guided to the exit surface 40a of the dichroic prism 40, respectively, and the light of each color is combined. The projection lens 10 is arranged adjacent to the exit surface 40 a of the dichroic prism 40, and the light combined by the dichroic prism 40 is projected from the projection lens 10.

FIG. 4 is an enlarged sectional view showing the attachment of the first dichroic mirror 24 to the first light tunnel 42. In this embodiment, each light pipe is provided with a groove 54 which is a component holding portion formed with a predetermined dimensional accuracy. As shown in FIG. 4, each dichroic mirror or mirror is fixed to each light tunnel by being fitted into the groove 54.

FIG. 5 shows each of the light tunnels 46, 50, 5
2 is a perspective view showing an assembled state of the liquid crystal plates 34, 36, 38 and the dichroic prism 40. FIG. 6 is a perspective view of a holding component 60 including the light tunnels, the liquid crystal plate, and the dichroic prism. It is a perspective view. Further, in order to simplify the drawing, each light tunnel in FIG. 5 is shown in a state of being cut off in the middle.

As shown in FIG. 6, the holding component 60 has a substantially hexahedral frame structure and has a prism receiving hole 62 for receiving the dichroic prism 40 inside.
And three liquid crystal plate holding recesses 64 for respectively holding the liquid crystal plates are formed. The prism receiving hole 62 is formed with a predetermined dimensional accuracy so that the dichroic prism 40 can be received and held without backlash. Liquid crystal plate holding recesses 64 are respectively formed on three of the four side surfaces of the holding component 60, and the light combined by the dichroic prism 40 is emitted from the remaining one side surface 65. Further, each liquid crystal plate holding recess 64 is
It has a liquid crystal plate contact surface 66 which is a support surface and an outer peripheral surface 68. The liquid crystal plate contact surface 66 is formed by the dichroic prism 40.
The liquid crystal plate is formed with a required dimensional accuracy so that the liquid crystal plate can be held in parallel with the incident surface at a predetermined distance. Further, on the outer side of the liquid crystal plate holding concave portion 64, a female screw hole 61a for screwing a screw 61 for fixing each light tunnel is provided.

As shown in FIG. 5, the dichroic prism 40 is dropped and held in a holding component 60. Further, in the liquid crystal plate 38, the outer edge portion of the plate surface is in contact with the liquid crystal plate contact surface 66 of the holding component 60, and the side surface of the liquid crystal plate is in contact with the outer peripheral surface 68. Is located in. Further, the sixth light tunnel 52 is formed so as to cover the liquid crystal plate holding concave portion 64 in which the liquid crystal plate 38 is arranged.
It is fixed to the holding component 60 by screws 61. As a result, the liquid crystal plate 38 causes the sixth light tunnel 52 and the holding component 6
It is sandwiched between 0 and. Similarly, the liquid crystal plate 36 is sandwiched between the third light tunnel 46 and the holding component 60, and the liquid crystal plate 34 is sandwiched between the fifth light tunnel 50 and the holding component 60.

Further, as shown in FIG. 5, the holding component 60 includes two adjusting screws 6 for each liquid crystal plate, that is, six adjusting screws 6 in total.
9 is attached. Each adjusting screw 69 is screwed into an adjusting female screw hole 69 a provided in the holding component 60. Each female screw hole 69a for adjustment is formed in the in-plane direction of each liquid crystal plate, and one end thereof is opened to the outer peripheral surface 68 of the holding component 60. Further, the female screw holes 69a for adjustment are provided at the midpoints of the upper sides and the midpoints of the lateral sides of each liquid crystal plate holding recess 64. With this configuration, when the adjusting screw 69 is screwed in, the side surface of the liquid crystal plate is pushed, and the liquid crystal plate can be moved on the liquid crystal plate contact surface 66.

FIG. 7 is a side sectional view of the first housing 2 taken along line VII-VII of FIG. As shown in FIG. 7, the light source 18 is
It has a lamp 70, a lamp reflector 72 that reflects the light of the lamp and directs the light to the first light tunnel, and an explosion-proof glass 74 that covers the opening of the lamp reflector 72. The lamp reflector 72 is formed in a curved surface shape represented by a set of parabolas that are vertically and horizontally symmetrical about the optical axis of the light emitted from the light source 18.

Axial fan 7 for cooling the illumination optical system
6 is arranged on the back surface of the lamp reflector 72.
The axial fan 76 is arranged such that its fan rotation axis is aligned with the optical axis of the light emitted from the light source 18. A duct 82 for directing the air introduced into the housing 2 by the axial fan 76 to the first light tunnel 42 is provided on the front surface side of the lamp reflector 72. Further, fins 84 are provided on the inner surface of the duct 82, and flow from the rear surface of the lamp reflector 72 toward the front surface, and direct a part of the air flowing into the duct 82 toward the light source 18. The upper surfaces of the duct 82, the light pipe 20, and the first to sixth light tunnels have a double wall structure having an inner wall 86 and an outer wall 88, and a passage for cooling air is provided between the inner wall 86 and the outer wall 88. 90 are configured. The passage 90 for the cooling air extends from the duct 82 to the light pipe 2.
0, through the first light tunnel 42, to communicate with all of the second to sixth light tunnel, the fifth light tunnel 50,
Third light tunnel 46 and sixth light tunnel 52
It leads to the tip of each.

Further, in order to allow heat to escape from each light tunnel to the housing 2, heat conduction sheets 80 of various thicknesses are attached to the light tunnel. The thermal conductive sheet 80 is made of a material having high thermal conductivity, and includes a light tunnel and a first thermal tunnel.
The thickness is such that it directly contacts both the housing 2 and the housing 2.

Next, the operation of the projector 1 according to the embodiment of the present invention will be described. When the projector 1 is used, the projector 1 is deformed from the housed state shown in FIG. 1 to the used state shown in FIG. 2 by rotating the first housing 2. In the use state, the second housing 4 functions as a leg of the projector 1. In addition, the second housing 4 also functions as a protective cover that protects the ventilation port 12 in the stored state and prevents dust and the like from entering through the ventilation port 12.

After the projector 1 is transformed into the use state, the operation switch 8 is operated to turn on the power of the projector 1. Then, the lamp 70 of the light source 18 is turned on by the operation switch 8.

The light emitted from the lamp 70 enters the light pipe 20 directly or after being reflected by the lamp reflector 72. The light that has passed through the light pipe 20 is converted into the polarization conversion element 21 and the first light tunnel 42.
Through the first condenser lens 22 mounted inside,
It is incident on the first dichroic mirror 24. The wavelength component of the red light of the light that has entered the first dichroic mirror 24 is reflected by the first dichroic mirror 24 and is directed into the second light tunnel 44. Second
The red light that has passed through the light tunnel 44 is reflected by the mirror 30 attached to the tip of the second light tunnel 44. The light reflected by the mirror 30 enters the fifth light tunnel 50 extending from the tip of the second light tunnel 44 at a right angle to the second light tunnel 44, and the liquid crystal plate 34 attached to the tip of the fifth light tunnel 50.
Incident on.

On the other hand, the wavelength components other than the red light in the light incident on the first dichroic mirror 24 are transmitted through the first dichroic mirror 24 and are incident on the second dichroic mirror 26. The wavelength component of the green light in the light incident on the second dichroic mirror 26 is reflected by the second dichroic mirror 26, is directed into the third light tunnel 46, and is attached to the tip of the third light tunnel 46. It is incident on the liquid crystal plate 36.

The blue light, which is the light of the wavelength component other than the green light in the light incident on the second dichroic mirror 26, passes through the second dichroic mirror 26 and enters the mirror 28. This blue light is reflected by the mirror 28 and directed into the fourth light tunnel 48,
The light passes through the second condenser lens 23 mounted in the fourth light tunnel 48. The blue light transmitted through the second condenser lens 23 is reflected by the mirror 32 attached to the tip of the fourth light tunnel 48. Mirror 32
The light reflected by the light enters the sixth light tunnel 52 extending from the tip of the fourth light tunnel 48 at a right angle to the fourth light tunnel 48, and the sixth light tunnel 52.
Enters the liquid crystal plate 38 attached to the tip of the.

The red light incident on the liquid crystal plate 34 is reflected by the liquid crystal plate 3.
It is modulated by 4 and enters the dichroic prism 40. The reflecting surface 40r provided in the dichroic prism 40 reflects red light and projects it onto the projection lens 1
Send to 0. Similarly, the green light that has entered the liquid crystal plate 36 is modulated by the liquid crystal plate 36 and enters the dichroic prism 40. The green light passes through the reflecting surfaces 40r and 40b provided in the dichroic prism 40 and enters the projection lens 10. The blue light that has entered the liquid crystal plate 38 is modulated by the liquid crystal plate 38 and enters the dichroic prism 40. The reflecting surface 40 b provided in the dichroic prism 40 reflects blue light and directs it to the projection lens 10. As a result, the lights modulated by the liquid crystal plates 34, 36 and 38 are combined by the dichroic prism 40 and the projection lens 1
It is incident on 0 and forms an image on the screen S.

Next, the cooling action on the illumination optical system will be described. The axial fan 76 sucks air from the outside of the first housing 2 through the ventilation port 12a and causes the air to flow from the rear side of the lamp reflector 72 toward the front side. The axial fan 76 is arranged so that its rotation axis is aligned with the optical axis that is the center of the lamp reflector 72, so that the lamp reflector 72 is symmetric about the optical axis in the vertical and horizontal directions. A uniform airflow is generated and the lamp reflector 7
Cool the back of 2 evenly. The air flowing along the back surface of the lamp reflector 72 enters a duct 82 provided in front of the lamp reflector 72. A part of the air that has entered the duct 82 is deflected by the fins 84 provided in the duct 82 to form a vortex. Since the fins 84 generate a vortex on the front side of the lamp reflector 72,
Air stagnation does not occur near the lamp reflector 72,
The peripheral portions of the lamp reflector 72 and the explosion-proof glass 74 are maintained at an appropriate temperature.

On the other hand, a part of the air flowing around the lamp reflector 72 flows into the passage 90 for the cooling air between the inner wall 86 and the outer wall 88 of the duct 82. This air flows into the passage 90 of the first light tunnel 42 through the passage 90 of the light pipe 20, and the cooling air between the inner wall 86 and the outer wall 88 of the second to sixth light tunnels that are in communication with each other. The respective light tunnels are cooled while flowing through the light passage 90, and ejected from the tips of the third, fifth, and sixth light tunnels, respectively. The air ejected from the tip of each light tunnel is
A liquid crystal panel 34 attached to the tip of each light tunnel,
Cool 36, 38. The air that has cooled each liquid crystal plate is discharged to the outside of the first housing through the ventilation port 12b. In this embodiment, as described above, the lamp 70 serving as a heat source, and
The illumination optical system 14, which requires cooling in particular, is cooled directly and intensively.

The lamp 70 and the lamp reflector 72 whose temperature is raised by the heat of the lamp not only transfer the heat to the surrounding air but also directly radiate the heat as an electromagnetic wave. In the projector according to the present embodiment, since the first housing 2 completely surrounds the lamps and the like serving as these main heat sources, the heat radiation from the lamp 70 and the like is stored in the second housing 4. It is not directly transmitted to the electronic circuit board 56 or the like. Further, the heat of each light tunnel is transmitted to the heat conduction sheet 80 attached to the light tunnel, and further,
The heat is transmitted to the first housing 2 that is in contact with the heat conductive sheet 80, and is radiated from the first housing 2 to the outside air.

According to this embodiment, the light source including the lamp and the lamp reflector, each light tunnel, and the illumination optical system such as the liquid crystal plate are centralized by the single axial fan attached to the back surface of the lamp reflector. And, it can be cooled efficiently. Further, the cooling air introduced by the axial fan uniformly flows from the back surface to the front surface of the lamp reflector, so that the lamp reflector is uniformly cooled. Therefore, thermal stress due to uneven thermal expansion is unlikely to occur in the lamp reflector, and damage to the lamp reflector can be prevented.

Although the preferred embodiments of the present invention have been described above, various modifications can be made to the disclosed embodiments within the scope of the technical matters described in the claims without departing from the scope or spirit of the present invention. Can be changed. In particular, in the above-described embodiment, the case where the present invention is applied to the liquid crystal projector has been described.
D (Digital Micro Mirror Device) and LCOS (Liq
It can also be applied to projectors that use uid crystal on silicon). Further, the fan for introducing the cooling air is not limited to the axial fan,
Any fan such as a sirocco fan can be used.

[0040]

According to the present invention, the optical system can be efficiently cooled without increasing the size of the projector body, and the lamp reflector of the lamp of the light source can be cooled uniformly.

[Brief description of drawings]

FIG. 1 is a perspective view of a projector according to an exemplary embodiment of the present invention in a stored state.

FIG. 2 is a perspective view of a projector according to an embodiment of the present invention in use.

FIG. 3 is a top sectional view of a projector according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing how a dichroic mirror is attached to a light tunnel.

FIG. 5 is a perspective view showing how liquid crystal plates are attached to a dichroic prism.

FIG. 6 is a perspective view of a holding component for holding each liquid crystal plate.

FIG. 7 is a sectional view taken along line VII-VII of FIG. 3 showing the structures of the light source and the duct.

[Explanation of symbols]

1 projector 2 First case 4 second housing 6 Hinge parts 8 operation switch 10 Projection lens 12 vents 14 Illumination optical system 16 Illumination optical system power supply 18 light source 20 light pipes 21 Polarization conversion element 22 First Condenser Lens 23 Second condenser lens 24 First Dichroic Mirror 26 Second Dichroic Mirror 28 mirror 30 mirror 32 mirror 34 LCD plate 36 LCD plate 38 LCD plate 40 dichroic prism 42 First Light Tunnel 44 Second Light Tunnel 46 Third Light Tunnel 48 Fourth Light Tunnel 50th Light Tunnel 52 6th Light Tunnel 54 groove 56 electronic circuit board 58 DC power supply 60 holding parts 61 Fixing screw 62 Prism receiving hole 64 LCD plate holding recess 66 Liquid crystal plate contact surface 68 outer peripheral surface 69 adjusting screw 70 lamp 72 lamp reflector 74 Explosion-proof glass 76 axial fan 80 Thermal conductive sheet 82 duct 84 fins 86 inner wall 88 outer wall 90 Passage for cooling air

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 5/74 H04N 5/74 E

Claims (3)

[Claims] 1. A liquid crystal plate, DM which emits light emitted from a light source.
In a projector which modulates by D or LCOS and projects from a projection lens, a light source provided with a lamp and a lamp reflector, and light emitted from the light source, which is arranged in front of the lamp reflector, is projected onto the projection lens. A projector comprising: a tubular light tunnel for guiding the air flow; and a fan for sending an air flow parallel to the optical axis of the light emitted from the light source from the back surface of the lamp reflector to the lamp reflector. 2. The light tunnel has an inner wall for forming an optical path for guiding the light from the light source to the projection lens, and an outer wall for forming a passage for cooling air outside the inner wall. The projector according to claim 1, wherein an air flow generated by the fan and cooling the lamp reflector is guided to the passage between the outer wall and the inner wall. 3. The projector according to claim 1, wherein the fan is an axial fan, and a rotation axis of the axial fan and an optical axis of the light source are aligned with each other.