JP2021071690A - Image projector - Google Patents

Abstract

To provide an image projector that can prevent entrance of powder dust while preventing increase of the temperature of the image projector.SOLUTION: An image projector 1 of the present invention includes: an illumination light optical system 4 for generating illumination light; an image display element 51 for modulating the illumination light and creating a projection light; a projection optical system 6 for enlarging the projection light; a housing 2 for containing the outside peripheries of the illumination optical system 4, the image display element 51, and the projection optical system 6 in a sealed state; a heat transfer unit 3A for transferring heat from a heat generation source in the housing 2; and a heat discharge unit 3 located outside the housing 2.SELECTED DRAWING: Figure 5

Description

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

The image projection device includes a control unit that controls the image display element in addition to the light source and 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 hot, the image projection device may be damaged.
For this reason, the image projection device has an intake fan and an exhaust fan arranged inside the housing, and the housing is provided with a plurality of holes for taking in air from the outside and allowing air to flow out to the outside. ..
When the housing is provided with holes in this way, dust floating outside the image projection device invades from the holes. If dust invades and adheres to the substrate of the control unit or the like, the portion may become hot and damaged. In addition, dust reduces the transmittance of the optical component, which causes deterioration of image quality.
For this reason, conventionally, a dustproof filter is attached to the intake port, and the inside of the housing is divided into an area where the optical components are arranged and an area where the control unit is arranged, and the area where the optical components are arranged is dustproof. There is an image projection device for which measures are taken to improve the performance (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-080957

However, even with the above-mentioned prior art, it is not possible to completely prevent the intrusion of dust into the housing, and when the image projection device is used outdoors, especially in a space where a large amount of dust exists, the temperature abnormality of the image projection device becomes abnormal. It was detected and stopped, or the performance of the image projection device deteriorated.

An object of the present invention is to provide an image projection device capable of preventing the intrusion of dust while preventing the temperature of the image projection device from rising.

An illumination optical system that generates illumination light, an image display element that modulates the illumination light to create projected light, a projection optical system that magnifies the projected light, the illumination optical system, the image display element, and the projection. An image projection device including a housing that houses the optical system in a sealed state, a heat transfer unit that transfers heat from a heat generation source inside the housing, and a heat dissipation unit that is provided outside the housing. I will provide a.

The heat radiating unit may have an intake fan, an exhaust fan, and a heat sink.

It is preferable that the intake fan and the exhaust fan are not arranged inside the housing, and the intake port and the exhaust port are not provided on the wall portion of the housing.

It is preferable that a control board for controlling the image projection device is arranged inside the housing.

It is preferable that the heat transfer unit transfers the heat of the heat source to the rear surface of the housing opposite to the front surface on which the projected light is irradiated.

A recess may be provided on the rear surface of the housing, and the heat radiating portion may be arranged in the recess.

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

The heat generation source includes a main substrate, and the main substrate may be arranged on the inner surface of a portion of the housing where the recess is not provided.

According to the present invention, it is possible to provide an image projection device capable of preventing the intrusion of dust while preventing the temperature of the image projection device from rising.

Is a perspective view of the image projection device 1 of the embodiment. It is a block diagram of an image projection device 1. It is a front view of the image projection device 1 in a state where the front housing 2F is removed. It is an exploded perspective view of the image projection device 1. It is a figure explaining the heat dissipation structure of an image projection apparatus 1.

Hereinafter, the image projection device 1 according to the embodiment of the present invention will be described.
FIG. 1 is a perspective view of the image projection device 1 of the embodiment. The image projection device 1 is a substantially rectangular parallelepiped, and includes a housing 2 and a heat radiating unit 3 arranged 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. 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 radiating unit 3 arranged outside the housing 2. Further, the image projection device 1 has an illumination optical system 4, an image display unit 5, a projection optical system 6, a concave reflector 7, an interface unit 9, and a control unit 8 for controlling these, inside the housing 2. And.

(Front housing 2F)
In the front housing 2F on the front side of the housing 2, an opening 25 for irradiating the projected light and an adjusting hole 21 for operating the focus adjusting unit 61, which will be described later, provided in the projection optical system 6 from the outside. And are provided.
Hereinafter, as shown in the figure, the side of the housing 2 where the opening 25 is provided is the front side, the opposite side is the rear side, and the direction in which the projected light travels in the optical axis OA of the projection optical system 6 is upward (enlarged side). ), The opposite side is set to the bottom (reduced side), and the left and right when the image projection device 1 is arranged vertically and viewed from the front will be described as left and right in the specification.

As shown in FIG. 1, a translucent 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 adjusting hole 21. The lid portion 26 can open and close the adjusting hole 21.

(Rear housing 2B)
As shown in FIGS. 3 and 4, a groove 22 is provided on the outer peripheral edge of the rear housing 2B on the rear surface side of the housing 2, and an elongated sealing member 23 having elasticity is arranged in the groove 22. An internal space 2Ba having a predetermined depth and in which the projection optical system 6 and the concave reflector 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 unit 5 are arranged.

When the seal member 23 is arranged in the groove 22 of the rear housing 2B, the front housing 2F is arranged in front of the rear housing 2B, and the periphery is fixed with screws 24 so as to bring them into close contact with each other. The state shown in FIG. 1 is such that the 2F and the rear housing 2B are fixed to each other. At this time, the opening 25 of the front housing 2F is sealed with the translucent member 27, and the interface portion 9 is also attached to the housing 2 in a dustproof manner. Therefore, when the adjustment hole 21 closes the lid portion 26, there are no other holes in the front housing 2F and the rear housing 2B, so that the inside of the housing 2 is dusty from the outside. It becomes a sealed state that does not invade.

Further, in the assembled state, the upper part of the housing 2 provided with the internal space 2Ba is thick (the front and rear width is large), the lower part is thin (the front and rear width is small), and the lower part is behind the mounting table 2Bb. A recess P is provided so that the side is recessed to provide a space in which the heat radiating portion 3 can be arranged. When the heat radiating portion 3 is arranged in the recess P, the housing 2 and the heat radiating portion 3 become substantially rectangular as a whole. Therefore, since the heat radiating unit 3 does not protrude from the housing 2, it does not hinder the installation of the image projection device 1.

(Illumination optical system 4)
The illumination optical system 4 includes, for example, RGB three-color LEDs 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. The light including the R light, the G light, and the B light generated from the light source in the illumination optical system 4 is incident on the image display unit 5.

(Image display unit 5)
The image display unit 5 includes an image display element (light modulation element) 51 and a prism 52 (displays only the reflecting surface).

(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 composed of a plurality of micromirrors, and each micromirror is time-dividedly driven based on the data received from the control unit 8 to emit the illumination light generated in the illumination optical system 4. When it is reflected, it is modulated to create a predetermined projected light, which is then incident on the projection optical system 6.
In the embodiment, 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 two-dimensionally, or the like can be appropriately used.

(Prism 52)
The prism 52 is a cross dichroic prism, which directs the illumination light generated by the illumination optical system 4 toward the image display element 51, and reflects the projected 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. The 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 projected light magnified by the projection optical system 6 to change the optical path, and guides the light path to the projection surface through the translucent member 27. This makes it possible to project an image or video at an ultra-wide angle.

(Heat dissipation part 3)
As shown in FIG. 4, the heat radiating unit 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 side and the exhaust fan 32 is attached to the right side, but the present invention is not limited to this, and vice versa.
The heat sink 33 includes a plurality of plate-shaped heat radiating fins 33a arranged in parallel with each other. The heat sink 33 extends between the intake fan 31 and the exhaust fan 32 so that air flows between the plurality of fins 33a so that the fins 33a extend in the direction from the intake fan 31 to the exhaust fan 32 (extend to the left and right). ) Is placed.

In FIGS. 1 and 4, the flow of air exhausted from the heat radiating unit 3 is indicated by an arrow. The arrow shown by the translucent member 27 in FIG. 4 is the direction in which the projected light travels. The air in the heat radiating unit 3 flows in a twisting direction different from the direction in which the projected light is irradiated, and does not intersect with the projected light. Therefore, the projected light is not disturbed by the high temperature air flowing from the heat radiating unit 3.

(Interface part 9)
The interface unit 9 is provided with a connection terminal unit 91 for connecting to the outside. An interface board 92 extends from these connection terminal units 91 to the inside of the housing 2, and power and input to the control unit 8 via the interface board 92, a flexible board 94 further extending from the interface board 92, and another interface board 95. A signal is sent, and further, power and a control signal are sent from the control unit 8 to the illumination optical system 4, the image display unit 5, and the heat dissipation unit 3.

(Control unit 8)
The control unit 8 is provided on the main board 8a arranged on the interface board 95 further extending 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 unit 8 controls the illumination optical system 4, the image display element 51, and the heat dissipation unit 3 based on the signal received from the interface unit 9. The control unit 8 operates the illumination optical system 4 and drives the intake fan 31 and the exhaust fan 32 of the heat dissipation unit 3. Then, the control unit 8 drives the image display element 51 based on the signal received via the interface unit 9. The image display element 51 generates projected light based on the control of the control unit 8.

(Effect of sealing)
In the present embodiment, the housing 2 is not provided with openings for attaching a fan, such as an intake port and an exhaust port, as described above. Further, the opening 25, which is another hole, is sealed with the translucent member 27, and the adjustment hole 21 for focus adjustment is covered with the lid portion 26. Therefore, the housing 2 is in a sealed state in which dust does not enter from the outside.
Therefore, when dust adheres to the main substrate 8a of the control unit 8, the possibility that the portion becomes high temperature and is damaged is reduced, and the life of the image projection device 1 is extended. In addition, dust reduces the transmittance of the optical component, which reduces the possibility of deterioration of image quality. Along with this, the image projection device 1 can be used for 20000H or more without maintenance.

(Heat dissipation structure)
On the other hand, since the housing 2 is hermetically sealed, air cannot be sent to the inside of the housing 2 for air cooling.
Therefore, in the embodiment, the housing 2 is made of metal having high thermal conductivity, and the heat of the heat generating source arranged in the housing 2 is transferred to the housing 2 to dissipate heat from the rear surface of the housing 2. Was provided.
FIG. 5 is a diagram illustrating a heat dissipation structure of the image projection device 1 of the embodiment. The heat radiating structure includes a heat transfer unit 3A provided inside the housing 2 or a part of the side surface of the housing 2, and a heat radiating unit 3 provided outside the housing 2.

(Heat source)
In the image projection device 1, the heat generating sources that become particularly hot during use are the image display element 51, the light sources 41, 42, 43, 44 of the illumination optical system, and the main substrate 8a.

(Heat transfer section 3A of image display element 51)
A metal base member 10 is fixed to the mounting base 2Bb of the metal rear housing 2B. The base member 10 and the mounting table 2Bb are in thermal contact with each other. In the specification, the thermal contact means that the contact is such that heat is transferred, and that the contact is such that heat energy can be transferred. 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 the metal heat pipe 12 is in thermal contact with the holding plate 51a on 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 the opening for holding the image display element 51 provided in the holding plate 51a, and the other end side is in thermal contact with the upper surface of the base member 10. The heat transfer unit 3A from the image display element 51 to the heat radiation unit 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 transferred to the heat pipe 12, the base member 10, and the mounting table 2Bb, which are the heat transfer portions 3A, through the holding plate 51a or by direct radiation.

(Heat transfer section 3A of the illumination optical system 4)
The light sources 41, 42, 43, and 44 of the illumination optical system 4 are, for example, LEDs, and when light is generated, the temperature becomes high. In the embodiment, the illumination optical system 4 includes four light sources 41, 42, 43, 44.
On the outside of the light sources 41 and 42, a heat receiver 11a is erected on the mounting table 2Bb to absorb the heat generated by the light sources 41 and 42. On the outside of the light source 43, a heat receiver 11b is erected on the mounting table 2Bb to absorb the heat generated by the light source 43. On the outside of the light source 44, a heat receiver 11c is erected on the mounting table 2Bb to absorb the heat generated by the light source 44.
The heat receivers 11a, 11b, and 11c are in thermal contact with the mounting table 2Bb. A thermal pad may be arranged between the heat receivers 11a, 11b, 11c and the base member 10. The heat transfer unit 3A from the illumination optical system 4 to the heat dissipation unit 3 includes heat receivers 11a, 11b, 11c and a mounting table 2Bb.
The heat generated by the light sources 41, 42, 43, 44 of the illumination optical system 4 is transferred to the heat receivers 11a, 11b, 11c, and the mounting table 2Bb, which are the heat transfer units 3A.

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

A heat radiating portion 3 is arranged in the space S on the rear surface of the mounting table 2Bb. The heat sink 33 of the heat radiating unit 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 heat radiating fins 33a of the heat sink 33.
When the intake fan 31 and the exhaust fan 32 are operated, air flows through the gap between the heat radiation fins 33a of the heat sink 33. The heat of the heat radiating fins 33a is taken away by this air flow and cooled. Then, by cooling the heat radiation fins 33a, the cooling of the image display element 51 and the light sources 41, 42, 43, 44 of the illumination optical system 4 is promoted via the mounting table 2Bb and the heat transfer unit 3A.

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

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

As described above, the heat generating 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 , The housing 2 is arranged on the inner surface of the mounting table 2Bb provided with the recess P on the back side.
That is, the light sources 41, 42, 43, 44, which are a part of the heat generation source, and the image display element 51 are integrated on the mounting table 2Bb. The portion where the heat generation sources are concentrated becomes hotter than the other portions in the housing 2, so that more heat dissipation is required.
In the embodiment, a heat radiating unit 3 having 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 the heat generating sources are concentrated.
Therefore, it is possible to satisfactorily dissipate heat from the mounting table 2Bb in which heat sources are concentrated, which requires more heat dissipation.

Further, the other part of the heat generating portion includes the main board 8a, and the main board 8a is arranged on the inner surface of the portion of the housing 2 where the internal space 2Ba without the recess P is provided. ..
That is, the main substrate 8a, which is another part of the heat generating portion, is different from the mounting table 2Bb in which the light sources 41, 42, 43, 44, which are a part of the heat generating portion, and the image display element 51 are collectively arranged. It is a part, and heat is dissipated from the bottom surface of the housing 2 provided in a stepped manner.
In this way, the heat generating source having a relatively small amount of heat is arranged at a position away from the integrated position of the heat generating source, and the heat generated is naturally dissipated from the rear surface of the housing 2. Since the rear surface of the housing 2 has a considerably larger area than the main substrate 8a, the heat of the main substrate 8a, which is a heat generation source having a relatively small amount of heat generation, is sufficiently dissipated.

Further, since the heat generation sources are dispersed and different heat transfer portions 3A are provided, heat is not concentrated in a part of the region, and the entire back surface of the housing 2 can be effectively used to efficiently dissipate heat.

Further, as described above, the heat generated in the image display element 51 is transferred to the heat pipe 12, the base member 10, and the mounting base 2Bb of the rear housing 2B, which are the heat transfer portions 3A, via the holding plate 51a or by direct radiation. Is transmitted to. Then, the heat generated in the main substrate 8a is transferred to the inner surface of the internal space 2Ba which is the heat transfer portion 3A. The heat of the inner surface of the internal space 2Ba heated by the main substrate 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 is not transferred to the front housing 2F, which is the side on which the projected light is irradiated.
Since the housing 2B side is attached to a wall or the like at the time of installation after the temperature becomes high, it is unlikely that a person will touch it. Further, since heat is not transferred to the front housing 2F which may be touched by a person, the safety is high, and the temperature of the optical path of the projected light does not rise, so that the image is less adversely affected.

1: Image projection device, 2: Housing, 2B: Rear housing, 2Ba: Internal space, 2Bb: Mounting stand, 2F: Front housing, 3: Heat sink, 3A: Heat transfer unit, 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: Seal member, 24: Screw, 25: Opening, 26: Lid, 27: Translucent member, 31: Intake fan, 32: Exhaust fan, 33: Heat sink, 33a: Heat dissipation fins, 41, 42, 43, 44: Light source, 51: Image display element, 51a: Holding plate, 52: Prism, 61: Focus adjustment unit, 91: Connection terminal unit, 92: Interface substrate

Claims (8)

Illumination optics that generate illumination light and
An image display element that modulates the illumination light to create projected light,
A projection optical system that magnifies the projected light,
A housing that houses the illumination optical system, the image display element, and the projection optical system in a hermetically sealed state.
A heat transfer unit that transfers heat from a heat source inside the housing,
A heat radiating unit provided on the outside of the housing and
An image projection device comprising. The heat radiating portion provided outside the housing has 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 housing, and an intake port and an exhaust port are not provided on the wall portion of the housing.
The image projection device according to claim 1 or 2. A control board for controlling the image projection device is arranged inside the housing.
The image projection device according to any one of claims 1 to 3. The heat transfer unit transfers the heat of the heat source to the rear surface of the housing opposite to the front surface to which the projected light is irradiated.
The image projection device according to any one of claims 1 to 4. A recess is provided on the rear surface of the housing, and the heat radiating portion is arranged in the recess.
The image projection device according to any one of claims 1 to 5. The heat generation source includes the light source of the illumination optical system and the image display element.
The light source and the image display element are arranged on the inner surface of the portion of the housing where the recess is provided.
The image projection device according to claim 6. The heat source includes a main substrate and includes a main substrate.
The image projection device according to claim 6 or 7, wherein the main substrate is arranged on the inner surface of a portion of the housing in which the recess is not provided.

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