JP7394586B2 - image projection device - Google Patents

Description

The present invention relates to an image projection device such as a projector that projects an image onto a screen or the like.

In addition to a light source and an image display element, the image projection apparatus includes a control section that controls the image display element. These light sources, image display elements, and control units generate heat, and if the inside of the image projection device becomes high temperature, the image projection device may be damaged.
For this reason, the image projection device is equipped with an intake fan and an exhaust fan inside the casing, and the casing is provided with a plurality of holes for sucking air in from the outside and discharging air to the outside. .
If a hole is provided in the housing in this way, floating dust enters the outside of the image projection device through the hole. If dust enters and adheres to the control board, etc., that part may become hot and may be damaged. In addition, the dust reduces the transmittance of optical components, which may cause deterioration of image quality.
For this reason, in the past, a dustproof filter was attached to the air inlet, and the inside of the housing was divided into an area where the optical components were placed and an area where the control unit was placed. There is an image projection device for which measures have been taken to improve performance (see Patent Document 1).

Japanese Patent Application Publication No. 2016-080957

However, even with the above conventional technology, it is not possible to completely prevent dust from entering the housing, and if the image projection device is used outdoors, especially in a space where there is a lot of dust, the temperature of the image projection device may be abnormal. This caused the image projection device to stop due to detection, or the performance of the image projection device to deteriorate.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image projection device that can prevent dust from entering the image projection device while preventing a rise in temperature of the image projection device.

an illumination optical system that generates illumination light; an image display element that modulates the illumination light to create projection light; a projection optical system that magnifies the projection light; the illumination optical system, the image display element, and the projection An image projection device comprising: a casing that seals an optical system therein; a heat transfer section that transfers heat from a heat generation source inside the casing; and a heat radiation section provided outside the casing. I will provide a.

The heat dissipation section may include an intake fan, an exhaust fan, and a heat sink.

Preferably, an intake fan and an exhaust fan are not disposed inside the casing, and an intake port and an exhaust port are not provided on a wall of the casing.

It is preferable that a control board for controlling the image projection device is disposed inside the casing.

It is preferable that the heat transfer section transfers the heat of the heat generation source to a rear surface of the housing that is opposite to a front surface that is irradiated with the projection light.

A recess may be provided on the rear surface of the casing, and the heat dissipation section may be disposed in the recess.

The heat generation source includes a light source of the illumination optical system and the image display element, and the light source and the image display element are arranged on an inner surface of a portion of the housing where the recess is provided. Good too.

The heat generation source may include a main board, and the main board may be arranged on an inner surface of a portion of the casing where the recess is not provided.

According to the present invention, it is possible to provide an image projection device that can prevent dust from entering while preventing the temperature of the image projection device from rising.

1 is a perspective view of an image projection device 1 according to an embodiment. 1 is a block diagram of an image projection device 1. FIG. FIG. 2 is a front view of the image projection device 1 with a front housing 2F removed. 1 is an exploded perspective view of an image projection device 1. FIG. 2 is a diagram illustrating a heat dissipation structure of the image projection device 1. FIG.

An image projection device 1 according to an embodiment of the present invention will be described below.
FIG. 1 is a perspective view of an image projection device 1 according to an embodiment. The image projection device 1 has a substantially rectangular parallelepiped shape and includes a housing 2 and a heat dissipation section 3 disposed outside the housing 2. The housing 2 includes a front housing 2F and a rear housing 2B, each of which is made of metal and has high thermal conductivity. FIG. 2 is a block diagram of the image projection device 1. As shown in FIG. FIG. 3 is a front view of the image projection device 1 with the front housing 2F removed. FIG. 4 is an exploded perspective view of the image projection device 1.

The image projection device 1 includes a housing 2 and a heat dissipation section 3 disposed outside the housing 2. Furthermore, the image projection device 1 includes, inside the housing 2, an illumination optical system 4, an image display section 5, a projection optical system 6, a concave reflecting mirror 7, an interface section 9, and a control section 8 for controlling these. Equipped with.

(Front housing 2F)
The front casing 2F on the front side of the casing 2 has an opening 25 for irradiating projection light and an adjustment hole 21 for operating a focus adjustment section 61, which will be described later, provided in the projection optical system 6 from the outside. and is provided.
Hereinafter, as illustrated, the side of the housing 2 where the opening 25 is provided is referred to as the front, the opposite side is referred to as the rear, and the direction in which the projection light of the optical axis OA of the projection optical system 6 travels is the upper (enlargement side). ), the opposite side is defined as the bottom (reduced side), and the left and right sides when viewed from the front with the image projection apparatus 1 disposed vertically are also referred to as left and right in the specification.

As shown in FIG. 1, a transparent member 27 such as a glass plate is attached to the opening 25 of the front housing 2F, and a lid 26 is attached to the adjustment hole 21. The lid part 26 can open and close the adjustment hole 21.

(Rear case 2B)
As shown in FIGS. 3 and 4, a groove 22 is provided on the outer peripheral edge of the rear casing 2B on the rear side of the casing 2, and an elongated elastic seal member 23 is disposed in the groove 22. An internal space 2Ba having a predetermined depth and in which the projection optical system 6 and the concave reflecting mirror 7 are arranged is provided in the upper part of the rear housing 2B. The lower part of the rear housing 2B has a substantially plate shape, and is provided with a mounting table 2Bb on which the illumination optical system 4 and the image display section 5 are arranged.

With the seal member 23 disposed in the groove 22 of the rear housing 2B, the front housing 2F is placed in front of the rear housing 2B, and when the periphery is fixed with screws 24 so as to bring them into close contact with each other, the front housing The state shown in FIG. 1 is reached in which the 2F and the rear housing 2B are fixed to each other. At this time, the opening 25 of the front casing 2F is sealed with a light-transmitting member 27, and the interface section 9 is also attached to the casing 2 in a dust-proof manner. Therefore, when the adjustment hole 21 closes the lid part 26, there are no other holes in either the front casing 2F or the rear casing 2B, so the inside of the casing 2 is free of dust from the outside. It is sealed to prevent intrusion.

In addition, in the assembled state, the casing 2 is thick at the upper part where the internal space 2Ba is provided (larger width from front to back), thinner at the lower part (smaller width from front to back), and the lower part is located behind the mounting table 2Bb. A recess P is provided, the side of which is recessed to provide a space in which the heat dissipation section 3 can be placed. When the heat dissipation section 3 is placed in the recess P, the housing 2 and the heat dissipation section 3 form a substantially rectangular shape as a whole. Therefore, since the heat dissipation section 3 does not protrude from the housing 2, it does not become an obstacle when installing the image projection device 1.

(Illumination optical system 4)
The illumination optical system 4 includes, for example, three-color LEDs of RGB as a light source. However, the light source is not limited to this, and may be, for example, an ultra-high pressure mercury lamp or a laser. Light including R light, G light, and B light generated from a light source in the illumination optical system 4 enters the image display section 5 .

(Image display section 5)
The image display section 5 includes an image display element (light modulation element) 51 and a prism 52 (only the reflective surface is displayed).

(Image display element 51)
The image display element 51 is, for example, a DMD (digital micromirror device). The DMD has a substantially rectangular mirror surface made up of a plurality of micromirrors, and based on data received from the control unit 8, each micromirror is driven in a time division manner, and the illumination light generated in the illumination optical system 4 is driven. When reflected, the light is modulated to create a predetermined projection light, which is then incident on the projection optical system 6.
In the embodiment, a DMD is used as the image display element 51, but the present invention is not limited to this, and a liquid crystal panel, a light emitting element array in which minute light emitting elements are arranged in a two-dimensional array, etc. can be used as appropriate.

(Prism 52)
The prism 52 is a cross dichroic prism that directs the illumination light generated by the illumination optical system 4 toward the image display element 51 and reflects the projection light created by the image display element 51 to the projection optical system 6.

(Projection optical system 6)
Although not shown in FIG. 5, the projection optical system 6 includes a plurality of lens groups. Note that details of the projection optical system 6 will be described later. The lens group is arranged along the optical axis OA with the optical axis OA as the center, and magnifies the image generated by the image display element 51.

(Concave reflector 7)
The concave reflecting mirror 7 reflects the projection light magnified by the projection optical system 6, changes the optical path, and guides the projection light through the light-transmitting member 27 to the projection surface. This makes it possible to project images or videos with an ultra-wide angle.

(Heat radiation part 3)
As shown in FIG. 4, the heat radiation section 3 includes one intake fan 31, two exhaust fans 32, and a heat sink 33, and is arranged in a recess P outside the housing 2. However, the number of intake fans 31 and exhaust fans 32 is not limited to this. Further, in the embodiment, the intake fan 31 is attached to the left and the exhaust fan 32 is attached to the right, but the present invention is not limited to this, and the opposite may be used.
The heat sink 33 includes a plurality of plate-shaped radiation fins 33a arranged in parallel with each other. The heat sink 33 is arranged between the intake fan 31 and the exhaust fan 32 so that the fins 33a are arranged along the direction from the intake fan 31 to the exhaust fan 32 (extending left and right) so that air flows between the plurality of fins 33a. ) is located.

In FIGS. 1 and 4, the flow of air exhausted from the heat radiating section 3 is indicated by arrows. Further, the arrow shown on the light-transmitting member 27 in FIG. 4 is the direction in which the projection light travels. The air in the heat dissipation section 3 flows in a twisted direction different from the direction in which the projection light is irradiated, and does not intersect with the projection light. Therefore, the projection light is not disturbed by the high temperature air flowing from the heat radiating section 3.

(Interface part 9)
The interface section 9 is provided with a connection terminal section 91 for connection with the outside. An interface board 92 extends from these connection terminals 91 into the housing 2, and provides power and input to the control unit 8 via the interface board 92 and a flexible board 94 and other interface boards 95 that further extend from the interface board 92. A signal is sent, and further power and control signals are sent from the control section 8 to the illumination optical system 4, image display section 5, and heat dissipation section 3.

(Control unit 8)
The control unit 8 is provided on a main board 8 a disposed on an interface board 95 that further extends from the interface board 92 . The main board 8a is arranged at the bottom of the internal space 2Ba of the rear housing 2B.

The control section 8 controls the illumination optical system 4 , the image display element 51 , and the heat dissipation section 3 based on the signal received from the interface section 9 . The control section 8 operates the illumination optical system 4 and also drives the intake fan 31 and exhaust fan 32 of the heat radiation section 3 . Then, the control section 8 drives the image display element 51 based on the signal received via the interface section 9. The image display element 51 generates projection light based on the control of the control section 8.

(Effect of sealing)
In this embodiment, the housing 2 is not provided with openings such as an intake port or an exhaust port for attaching a fan as described above. Further, the opening 25, which is another hole, is sealed with a light-transmitting member 27, and the adjustment hole 21 for focus adjustment is covered with a lid 26. Therefore, the casing 2 is in a sealed state to prevent dust from entering from the outside.
Therefore, when dust adheres to the main board 8a of the control unit 8, the possibility that that part becomes hot and is damaged is reduced, and the life of the image projection device 1 is extended. Further, the possibility that the transmittance of the optical component is reduced due to dust and that the image quality is deteriorated due to this is reduced. Accordingly, the image projection device 1 can be used for 20,000 hours or more without maintenance.

(heat dissipation structure)
On the other hand, since the casing 2 is sealed, air cannot be sent into the casing 2 for air cooling.
For this reason, in the embodiment, the casing 2 is made of metal with high thermal conductivity, and has a heat dissipation structure that transmits heat from a heat generation source placed inside the casing 2 to the casing 2 and radiates the heat from the rear surface of the casing 2. has been established.
FIG. 5 is a diagram illustrating the heat dissipation structure of the image projection device 1 according to the embodiment. The heat radiation structure includes a heat transfer part 3A that is provided inside the housing 2 or is a part of the side surface of the housing 2, and a heat radiation part 3 that is provided outside the housing 2.

(source of heat generation)
In the image projection device 1, the heat generation sources that become particularly high in temperature during use are the image display element 51, the light sources 41, 42, 43, and 44 of the illumination optical system, and the main board 8a.

(Heat transfer part 3A of image display element 51)
A metal base member 10 is fixed to the mounting table 2Bb of the metal rear housing 2B. The base member 10 and the mounting table 2Bb are in thermal contact. Note that the term "thermal contact" as used herein means contacting such that heat can be transmitted, or contacting such that thermal energy can be transmitted. Further, a thermal pad may be arranged between the base member 10 and the mounting table 2Bb.

The image display element 51 is held by a metal holding plate 51a and is arranged above the base member 10. One end side of a metal heat pipe 12 is in thermal contact with the front surface of the image display element 51 and the holding plate 51a. The heat pipe 12 is bent toward the rear side across an opening provided in the holding plate 51a for holding the image display element 51, and the other end side is in thermal contact with the upper surface of the base member 10. The heat transfer section 3A from the image display element 51 to the heat radiation section 3 includes a heat pipe 12, a base member 10, and a mounting table 2Bb.
The heat generated in the image display element 51 is transmitted to the heat pipe 12, which is the heat transfer section 3A, the base member 10, and the mounting table 2Bb via the holding plate 51a or by direct radiation.

(Heat transfer part 3A of illumination optical system 4)
The light sources 41, 42, 43, and 44 of the illumination optical system 4 are, for example, LEDs, and when they generate light, the temperature becomes high. In the embodiment, the illumination optical system 4 includes four light sources 41, 42, 43, and 44.
A heat receiver 11a is erected on the mounting table 2Bb outside the light sources 41 and 42, and absorbs the heat generated by the light sources 41 and 42. Outside the light source 43, a heat receiver 11b is installed upright on the mounting table 2Bb, and absorbs the heat generated by the light source 43. Outside the light source 44, a heat receiver 11c is provided upright on the mounting table 2Bb, and absorbs the heat generated by the light source 44.
Each of the heat receivers 11a, 11b, and 11c is in thermal contact with the mounting table 2Bb. Note that a thermal pad may be placed between the heat receivers 11a, 11b, 11c and the base member 10. The heat transfer section 3A from the illumination optical system 4 to the heat radiation section 3 includes heat receivers 11a, 11b, 11c and a mounting table 2Bb.
Heat generated in the light sources 41, 42, 43, and 44 of the illumination optical system 4 is transmitted to the heat receivers 11a, 11b, and 11c, which are the heat transfer section 3A, and the mounting table 2Bb.

(Heat radiation part 3)
The heat transferred from the image display element 51 by the heat transfer section 3A and the heat transferred from the illumination optical system 4 by the heat transfer section 3A heat the mounting table 2Bb. Since the mounting table 2Bb is made of metal with high thermal conductivity, heat is transferred to the rear surface of the mounting table 2Bb.

A heat radiating section 3 is arranged in a space S on the rear surface of the mounting table 2Bb. The heat sink 33 of the heat radiation section 3 is in thermal contact with the rear surface of the mounting table 2Bb. Therefore, the heat on the rear surface of the mounting table 2Bb is transferred to the radiation fins 33a of the heat sink 33.
When the intake fan 31 and the exhaust fan 32 are operated, air flows through the gaps between the radiation fins 33a of the heat sink 33. This air flow removes heat from the radiation fins 33a and cools them. By cooling the radiation fins 33a, cooling of the image display element 51 and the light sources 41, 42, 43, and 44 of the illumination optical system 4 is promoted via the mounting table 2Bb and the heat transfer section 3A.

(Heat transfer part 3A of main board 8a)
The main board 8a of the control section 8 is arranged on the bottom surface of the internal space 2Ba of the rear housing 2B and is in thermal contact with the main board 8a. A thermal pad may be placed between the bottom surface of the internal space 2Ba and the main board 8a. The heat transfer section 3A of the main board 8a includes the bottom surface of the internal space 2Ba.
The heat generated in the main board 8a is transmitted to the inner surface of the internal space 2Ba, which is the heat transfer section 3A. The heat on the inner surface of the internal space 2Ba heated by the main board 8a is transferred to the rear surface. The heat transferred to the rear surface is then radiated directly to the outside.

The area of the bottom of the internal space 2Ba is sufficiently larger than that of the main board 8a. Therefore, when the heat of the main board 8a is radiated from the bottom of the internal space 2Ba, the main board 8a is sufficiently cooled.

In this way, the heat source of the image projection device 1 includes the light sources 41, 42, 43, 44 of the illumination optical system 4 and the image display element 51, and the light sources 41, 42, 43, 44 and the image display element 51 are , is arranged on the inner surface of the mounting table 2Bb in the housing 2, which has a recess P on the back side.
That is, the light sources 41, 42, 43, and 44, which are part of the heat generation sources, and the image display element 51 are integrated on the mounting table 2Bb. A portion where heat sources are concentrated has a higher temperature than other portions of the casing 2, and therefore requires more heat radiation.
In the embodiment, the heat radiating section 3 including an intake fan 31, an exhaust fan 32, and a heat sink 33 is arranged on the rear surface of the mounting table 2Bb where heat sources are concentrated.
Therefore, it is possible to efficiently radiate heat from the mounting table 2Bb, which requires more heat radiation and in which heat sources are concentrated.

Further, the other part of the heat generating part includes a main board 8a, and the main board 8a is arranged on the inner surface of the part of the housing 2 where the internal space 2Ba is provided and where the recess P is not provided. .
That is, the main board 8a, which is another part of the heat generating part, is different from the mounting table 2Bb, on which the light sources 41, 42, 43, 44 and the image display element 51, which are part of the heat generating part, are arranged together. Heat is radiated from the bottom surface of the casing 2, which is provided at different levels.
In this way, a heat source with a relatively small amount of heat is disposed at a position away from the location where the heat sources are concentrated, and the heat generated is naturally radiated from the rear surface of the casing 2. Since the rear surface of the housing 2 has a considerably wider area than the main board 8a, the heat of the main board 8a, which is a heat source with a relatively small amount of heat, is sufficiently radiated.

Furthermore, since the heat generation sources are dispersed and different heat transfer parts 3A are provided, heat is not concentrated in a certain area, and the entire back surface of the casing 2 can be effectively utilized to efficiently dissipate heat.

Further, as described above, the heat generated in the image display element 51 is transferred to the heat pipe 12 which is the heat transfer section 3A, the base member 10, and the mounting table 2Bb of the rear housing 2B via the holding plate 51a or by direct radiation. transmitted to. Then, the heat generated in the main board 8a is transmitted to the inner surface of the internal space 2Ba, which is the heat transfer section 3A. The heat on the inner surface of the internal space 2Ba heated by the main board 8a is transferred to the rear housing 2B.
That is, the heat generated inside the housing 2 is transmitted to the rear housing 2B and not to the front housing 2F, which is the side to which the projection light is irradiated.
The rear housing 2B side, which becomes hot, is attached to a wall or the like during installation, so there is a low possibility that people will touch it. Since heat is not transferred to the front housing 2F, which may be touched by a person, safety is high, and since the temperature of the optical path of the projection light does not increase, there is little adverse effect on the image.

1: Image projection device, 2: Housing, 2B: Rear housing, 2Ba: Internal space, 2Bb: Mounting table, 2F: Front housing, 3: Heat dissipation section, 3A: Heat transfer section, 4: Illumination optical system, 5: Image display unit, 6: Projection optical system, 7: Concave reflector, 8: Control unit, 8a: Main board, 9: Interface unit, 10: Base member, 11a, 11b, 11c: Heat receiver, 12: Heat pipe, 21: adjustment hole, 22: groove, 23: sealing member, 24: screw, 25: opening, 26: lid, 27: transparent member, 31: intake fan, 32: exhaust fan, 33: heat sink, 33a: radiation fin, 41, 42, 43, 44: light source, 51: image display element, 51a: holding plate, 52: prism, 61: focus adjustment section, 91: connection terminal section, 92: interface board

Claims (5)

An image projection device,
an illumination optical system that generates illumination light;
an image display element that modulates the illumination light to create projection light;
a projection optical system that magnifies the projection light;
a housing in which the illumination optical system, the image display element, and the projection optical system are housed in a sealed state;
Equipped with
If the side of the housing where the opening for irradiating the projection light is defined as the front side of the image projection device, and the opposite side as the rear side of the image projection device,
The casing includes a front casing and a rear casing,
The front casing is provided with the opening,
The rear housing is provided with an internal space in which the projection optical system is arranged, and a mounting table in which the illumination optical system and the image display element are arranged,
A recess is provided in the rear casing in which the outside of the mounting base is recessed, and a heat dissipation part is disposed in the recess,
An image projection device in which heat generated by the light source of the illumination optical system and the image display element is transmitted to the heat radiating section via the mounting table, and is radiated from the heat radiating section . The heat radiation section includes an intake fan, an exhaust fan, and a heat sink.
The image projection device according to claim 1. An intake fan and an exhaust fan are not arranged inside the casing, and an intake port and an exhaust port are not provided on the wall of the casing.
The image projection device according to claim 1 or 2. If the direction in which the projection light travels through the projection optical system is defined as the upper side of the image projection device, and the opposite side is defined as the lower side of the image projection device,
A main board provided with a control unit for controlling the image projection device is disposed on a bottom surface that is a lower wall surface of the internal space.
An image projection device according to any one of claims 1 to 3. A sealing member is disposed at a connecting portion between the front casing and the rear casing,
An image projection device according to any one of claims 1 to 4.

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