JP2017223844A - Image projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image projection device capable of cooling a projection lens while maintaining dust-proof effect of the projection lens.SOLUTION: An image projection device such as a projector 1 projects light of a projection image generated by an image generation element such as a DMD21 based on image data using light of a light source 11 onto a projection surface 101 via at least one projection lens 42. Each of an injection side section and an emission side section of a chassis is sealed in such a way that the projection image light can be penetrated and flows out ambient air taken into the image projection device into an outer peripheral section where the chassis is under an exposed state while the outer peripheral section of the chassis between the injection side section where the projection image light is injected in the chassis such as a lens-barrel 41 for holding a projection lens and the emission side section where the projection image light in the chassis is emitted is exposed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image projection apparatus.

  2. Description of the Related Art Conventionally, there has been known an image projection apparatus that projects a projection image generated by an image generation element based on image data using light from a light source onto a projection surface using a projection lens.

  For example, Patent Document 1 discloses such an image projection apparatus, in which an image projection apparatus in which a heat sink is provided on a lens barrel cover as one member constituting a lens barrel that is a housing that holds a plurality of projection lenses is disclosed. Yes. In the image projection apparatus, the projection lens is heated because light from the light source is transmitted, the projection lens is thermally expanded in the thickness direction, and the focus of the projection image is shifted. For this reason, outside air is taken into the image projection device, the outside air is flowed toward the heat sink in the image projection device, and the lens barrel is cooled, thereby cooling the projection lens held in the lens barrel.

  According to the image projection apparatus disclosed in Patent Document 1, dust and dust contained in the outside air are incident on the incident side of the lens barrel on which the projection image light is incident and on the emission side of the lens barrel on which the projection image light is emitted. It adheres to the projection lens provided in the. As a result, the light of the projection image which goes to the projection surface side is shielded by dust or dirt adhering to the projection lens, and an image missing portion is generated in the projection image on the projection surface. If the entire lens barrel is surrounded for dust prevention, it is not possible to flow outside air through the heat sink. Therefore, there is a problem that the cooling system using the heat sink cannot be used and the projection lens cannot be cooled sufficiently.

  In order to solve the above-described problem, the present invention provides an image projection apparatus that projects light of a projection image generated by an image generation element based on image data using light of a light source onto a projection surface via at least one projection lens. The outer peripheral portion of the casing is exposed between the incident-side portion where the projection image light is incident on the casing holding the projection lens and the emission-side portion where the projection image light is emitted from the casing. Thus, the incident side portion and the emission side portion of the casing are sealed so as to be able to transmit the projection image light, and the outside air taken into the image projection apparatus flows through the exposed outer peripheral portion of the casing. It is characterized by this.

  According to the present invention, it is possible to obtain a specific effect that the projection lens can be cooled well while maintaining the dustproof effect of the projection lens.

The perspective view which shows the projector and projection surface which concern on this embodiment. FIG. 3 is a schematic diagram illustrating a projector according to the present embodiment. The perspective view which shows a light source unit, a projection image generation unit, and a projection optical unit. FIG. 4 is an external perspective view of FIG. 3. FIG. 2 is an exploded perspective view of a part of the projector according to the present embodiment. The elements on larger scale of FIG. The side view of FIG. The side view when attaching a lens-barrel to a thermal radiation cover with a heat conductive sheet. FIG. 3 is a schematic diagram illustrating the air flow in the projector according to the present embodiment. The schematic diagram seen from the arrow A of FIG. FIG. 3 is an exploded perspective view illustrating the air flow in the projector according to the present embodiment.

Hereinafter, an embodiment of a projector as an image projection apparatus to which the present invention is applied will be described.
FIG. 1 is a perspective view showing a projector 1 and a projection surface 101 such as a screen according to the present embodiment. In the following description, the normal direction of the projection plane 101 is the X direction, the short axis direction (vertical direction) of the projection plane is the Y direction, and the long axis direction (horizontal direction) of the projection plane 101 is the Z direction.

  As shown in FIG. 1, a transmissive glass 61 from which a projection image P is emitted is provided on the upper surface of the projector 1, and the projection image P emitted from the transmissive glass 61 is projected onto a projection surface 101 such as a screen. . Further, on the upper surface of the projector 1, an operation unit 62 is provided for the user to operate the projector 1. A focus lever 63 for adjusting the focus is provided on the side surface of the projector 1.

FIG. 2 is a schematic diagram illustrating the projector according to the present embodiment.
As shown in FIG. 2, the projector includes a light source unit 10 including a light source 11 such as a halogen lamp, a metal halide lamp, and a high-pressure mercury lamp, and a DMD (Digital Micro-) that is a micro-drive mirror device using light from the light source 11. mirror device) 21, a projection image generation unit 20 that is a projection image generation unit that generates a projection image, an illumination optical unit 30 that is an illumination optical unit that guides light from the light source 11 to the DMD 21, and a projection optical unit that emits a projection image A projection optical unit 40. The illumination optical unit 30 includes a color wheel 31, a light tunnel 32, two relay lenses 33, a plane mirror 34, and a concave mirror 35.

  The light from the light source 11 is separated into R, G, and B light in a time-division manner by passing through the rotating color wheel 31 as indicated by arrows in FIG. The color wheel 31 has a disk shape, is fixed to the motor shaft of the motor 31a, and is provided with filters such as R (red), G (green), and B (blue) in the rotation direction. The light separated by the color wheel 31 enters the light tunnel 32.

  The light tunnel 32 has a rectangular tube shape, and its inner peripheral surface is a mirror surface. The light that has entered the light tunnel 32 is reflected by the mirror surface on the inner periphery of the light tunnel 32 a plurality of times and is emitted as a uniform surface light source toward the two relay lenses 33. The light passes through the two relay lenses 33, is reflected by the next-stage flat mirror 34 and concave mirror 35, and is focused on the image generation surface of the DMD 21 to form an image.

  Here, a plurality of movable micromirrors are arranged in a lattice pattern on the image generation surface of the DMD 21. Each micromirror can incline the mirror surface by a predetermined angle around the twist axis, and can have two states of “ON” and “OFF”. When the micromirror is “ON”, the light from the light source 11 of the light source unit 10 is reflected toward the projection lens 42 of the projection optical unit 40. When “OFF”, the light from the light source 11 is reflected toward an OFF light plate held on a side surface such as an illumination bracket. Therefore, by driving each mirror individually, light projection can be controlled for each pixel of the image data, and an image can be generated.

  In addition, the light reflected toward the OFF light plate is absorbed as heat and cooled by the flow of outside air. The two relay lenses 33 are positioned and held by pressing both ends against the abutting surface of the lens bracket by a plate spring-like lens pressing member.

  A projector 1 shown in FIG. 2 generates an image based on image data input from a personal computer, a video camera, or the like, and projects and displays the image on a projection surface such as a screen. A liquid crystal projector widely known as the projector 1 has recently been improved in the resolution, the price, and the like with an increase in the resolution of the liquid crystal panel, the efficiency of the light source lamp. In addition, a small and lightweight projector 1 using the DMD 21 that is an image generating element has been widely used, and has been widely used not only in offices and schools but also at home.

  The light from the light source 11 is split into RGB by the color wheel 31 in the illumination optical unit 30 and guided to the DMD 21 of the projection image generation unit 20. The DMD 21 generates a projection image according to the modulation signal. Then, the projection image generated by the DMD 21 is incident on the projection lens 42. The incident projection image is emitted from the projection lens 42 provided on the exit side portion of the lens barrel 41, enlarged by the folding mirror 43 and the concave curved mirror 44, and projected onto the projection surface.

FIG. 3 is a perspective view showing a light source unit, a projection image generation unit, and a projection optical unit. FIG. 4 is an external perspective view of FIG.
As shown in FIG. 3, the projection optical unit 40 includes a projection lens that is held by a lens barrel 41 that is a projection lens holding unit, a folding mirror 43, and a concave curved mirror 44. The surface of the curved mirror 44 that reflects light can be a spherical surface, a rotationally symmetric aspherical surface, a free curved surface shape, or the like. As shown in FIG. 4, the projection optical unit 40 transmits a light image reflected from the curved mirror 44 and also includes a dustproof glass 45 for dustproofing the optical system components in the apparatus.

  Further, as shown in FIG. 4, the projection optical unit 40 includes a mirror bracket 46 that holds the folding mirror 43 and the dust-proof glass 45, a free mirror bracket 47 that holds the curved mirror 44, a mirror bracket 46, and a free mirror bracket. And a mirror holder 48 to which 47 is attached.

  The mirror bracket 46 is attached to the upper part of the mirror holder 48. The mirror bracket 46 has an inclined surface that is inclined so as to rise from the front end portion in the X direction in the drawing in contact with the inclined portion of the upper opening edge of the mirror holder 48 in the X direction. In addition, the mirror holder 48 has a parallel surface parallel to the X direction that contacts the parallel portion of the upper opening edge. The inclined surface and the parallel surface each have an opening, the folding mirror 43 is held so as to close the opening on the inclined surface, and the dustproof glass 45 is held so as to close the opening on the parallel surface. Has been.

  The mirror holder 48 has a box shape, and the upper surface, the lower surface, and the back side in the X direction in FIG. 3 are open, and has a substantially U-shape when viewed from above. Edge portions extending in the X direction on the front side and the back side in the Z direction of the upper opening of the mirror holder 48 are constituted by an inclined portion and a parallel portion. The inclination part inclines so that it may rise as it goes to the X direction back | inner side from the X direction near side edge part in FIG. The parallel part is parallel to the X direction in FIG. Further, the inclined portion is on the front side in the X direction in FIG. 3 from the parallel portion. Further, the edge of the upper opening of the mirror holder 48 extending in the Z direction on the near side in the X direction in the drawing is parallel to the Z direction in FIG.

  The folding mirror 43 is positioned and held on the inclined surface of the mirror bracket 465 by pressing both ends of the folding mirror 43 against the inclined surface of the mirror bracket 46 by a plate spring-like mirror pressing member. The end of the folding mirror 43 is fixed by three mirror pressing members.

  The dust-proof glass 45 is positioned and fixed to the mirror bracket 46 by being pressed against the parallel surface of the mirror bracket 46 by three plate spring-like glass pressing members 49.

  The free mirror bracket 47 that holds the curved mirror 44 has arm portions that are inclined so as to descend from the X-direction back side toward the front side in FIG. 3 on the Z-axis direction front side and the back side. Further, the free mirror bracket 47 has a connecting portion that connects these two arm portions at the upper portion of the arm portion. The free mirror bracket 47 is attached to the mirror holder 48 so that the curved mirror 44 covers the opening of the mirror holder 48 on the back side in the X direction in FIG.

  The upper end of the curved mirror 44 and the substantially central portion of the side end portion of the dust-proof glass 45 are pressed against the connecting portion of the free mirror bracket 47 by a plate spring-like free mirror pressing member. Further, both ends of the curved mirror 44 in the Z-axis direction in FIG. 3 are fixed to the arm portion of the free mirror bracket 47 by screws.

Next, features of the present invention will be described.
Since the projection lens of the projection optical unit transmits most of the light emitted from the light source, the projection lens becomes high temperature, and the projection lens itself and the lens barrel thermally expand, which may cause a focus shift of the projected image. Furthermore, if the projection lens is a bonded lens, it may be peeled off or damaged due to the difference in thermal expansion of the bonded lens. In these cases, the lens barrel can be changed to a material having high thermal conductivity, such as aluminum, and the lens barrel can be cooled by applying air. However, an ultra-short focus projector requires a light magnifying device with a curved mirror that further magnifies the light that has passed through the projection lens, and also contains a lens barrel that holds the projection lens and a light magnifying device for dust protection. The housing to be sealed has a sealed structure. Therefore, it was not possible to cool the lens barrel by flowing air.

  In the projector according to the present embodiment, the incident side portion of the lens barrel on which the projection image light is incident and the emission side portion of the lens barrel on which the projection image light is emitted are sealed so as to transmit the projection image light. Thereby, it can suppress that dust and dust adhere to the projection lens provided in the entrance side part and exit side part of a lens-barrel. Moreover, the space between the incident side portion and the emission side portion of the lens barrel is exposed, and heat of the lens barrel can be radiated by flowing outside air through the exposed portion of the lens barrel. Thereby, the temperature rise of the projection lens held by the lens barrel can be suppressed.

  Furthermore, the incident side portion of the lens barrel is brought into contact with a member constituting an illumination optical unit configured in a heat sink shape (heat radiation shape). Thereby, the heat of the lens barrel can be transmitted to the member of the illumination optical unit and can be radiated from the member. Therefore, while maintaining dust-proof measures, the thermal expansion of the lens barrel and the projection lens is reduced to suppress the shift in the focus of the projected image, and the peeling and breakage due to the difference in the thermal expansion coefficient between the bonded lenses are suppressed. Higher brightness can be realized. This will be described in detail below.

  FIG. 5 is an exploded perspective view of a part of the projector according to the present embodiment. FIG. 6 is a partially enlarged view of FIG. FIG. 7 is a side view of FIG. FIG. 8 is a side view when the lens barrel is attached to the heat radiation cover together with the heat conductive sheet.

  As shown in FIG. 5, the lens barrel 41 is fixed to the projection lens fixing bracket 50. A heat radiation cover 51 having heat radiation fins 51 a is provided on the upper portion of the illumination optical unit 30. The heat radiating cover 51 is formed with a groove 51 b for loading the ring-shaped heat conductive sheet 52 and an opening 51 c for allowing a part of the lens barrel 41 to enter the housing constituting the illumination optical unit 30. . In addition, it may replace with the heat conductive sheet 52, and may use the heat conductive grease which mixed the particle | grains with high heat conductivity.

  As shown in FIGS. 5, 6, and 7, the incident side portion of the lens barrel 41 passes through the inside of the heat conductive sheet 52 installed in the groove portion 51 b and dissipates heat attached to the upper surface of the illumination optical unit 30. The light enters the illumination optical unit 30 through an opening 51 c opened in the cover 51. In this state, the projection lens fixing bracket 50 is fixed with screws by aligning the screw through holes of the projection lens fixing bracket 50 with the screw portions provided on the upper surface of the housing of the illumination optical unit 30. The incident side portion of the lens barrel on which the projection image light is incident enters the inside of the sealed illumination optical unit, and the emission side portion of the lens barrel on which the projection image light is emitted is also surrounded by a casing constituting the projection optical unit. Thereby, it can suppress that dust and dust adhere to the projection lens provided in the entrance side part and exit side part of a lens-barrel.

Furthermore, since the screw part provided on the upper surface of the illumination optical unit 30 has a predetermined height, a gap is formed between the projection lens fixing bracket 50 and the heat dissipation cover 51. When the projection lens fixing bracket 50 is attached to the heat dissipation cover 51, as shown in FIG. 8, the heat dissipation portion 41a such as aluminum integrally formed with the lens barrel 41 exposed in the gap comes into contact with the heat conductive sheet 52. The heat radiation cover 51 also contacts the heat conductive sheet 52. Thereby, the heat of the lens barrel 41 warmed by the heat of the projection lens is transmitted to the heat dissipation cover 51 via the heat conductive sheet 52. The transmitted heat is released to the surroundings by the radiating fins formed on the radiating cover 51.
As described above, the projection lens can be cooled while maintaining the dustproof effect of the projection lens.

FIG. 9 is a schematic diagram illustrating the flow of air in the projector according to the present embodiment. FIG. 10 is a schematic view seen from the arrow A in FIG. FIG. 11 is an exploded perspective view illustrating the air flow in the projector according to the present embodiment.
As shown in FIGS. 9 and 10, the projector housing is provided with an air inlet 53, and the projector housing on the opposite side of the installation location of the air inlet 53 is provided with an exhaust port 54. Yes. Further, an exhaust fan 55 is provided at the exhaust port 54.

  When the exhaust fan 55 is rotated, ambient air is taken in from the intake port 53 and flows into the projector 1. As shown by the arrows in FIGS. 9 and 11, the air taken in from the air inlet 53 passes through the gap between the illumination optical unit 30 and the projection optical unit 40, and at that time, the heat radiation cover 51 and the heat radiation portion of the lens barrel 41. Heat is taken from 41a, and the heated air passes through the vent 56 and is discharged from the exhaust. Thereby, the cooling efficiency of the heat radiation cover 51 and the lens barrel 41 is further increased. In addition, the cooling effect of the lens barrel 41 can be further enhanced by cooling the lens barrel 41 by forming an air flow path through which the air taken in from the intake port 53 flows to the heat radiation portion 41a of the lens barrel 41.

  In addition, the member which comprises an illumination optical unit is formed with the material which contains aluminum or aluminum with high heat conductivity, or the material containing copper or copper. Thereby, the heat dissipation efficiency of the heat of the lens barrel can be increased. Furthermore, part or all of the members constituting the lens barrel are also formed of aluminum or a material containing aluminum. Thereby, the heat radiation efficiency of the projection lens held by the lens barrel can be increased.

What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.
(Aspect A)
In an image projection apparatus such as a projector 1 that projects light of a projection image generated by an image generation element such as a DMD 21 based on image data using light of a light source 11 onto a projection surface 101 via at least one projection lens 42. An outer peripheral portion of the housing between the incident side portion where the projection image light enters in the housing such as the lens barrel 41 holding the projection lens and the emission side portion where the projection image light exits in the housing is exposed. In this state, the incident side portion and the emission side portion of the casing are sealed so as to be able to transmit the projection image light, and outside air taken into the image projection apparatus is exposed to the outer peripheral portion of the casing. It is characterized by flowing in
According to this aspect, the incident side portion and the emission side portion of the housing are present apart from the outer peripheral portion of the housing that is exposed. For this reason, when the outside air taken into the image projection apparatus is passed through the outer peripheral part of the exposed state of the casing, most of the dust and dirt contained in the outer air adhere to the outer peripheral part, but the dust and dirt are It is difficult to move to the incident side and the exit side and adhere to the projection lens on the entrance side and the exit side. Further, the incident side portion and the emission side portion of the housing are hermetically sealed, and dust and dirt are prevented from directly adhering to the projection lens. Moreover, since the outer peripheral portion between the incident side portion and the emission side portion of the housing is exposed, the outside air can be flowed to the exposed portion, and the heat of the housing holding the projection lens can be dissipated, Cooling of the projection lens held in the housing can be promoted. As described above, the projection lens can be cooled while keeping the projection lens dust-proof.

(Aspect B)
In (Aspect A), an illumination optical unit that guides light from the light source to the image generation element is provided, and the illumination optical unit includes an incident-side portion of the housing in a housing that constitutes the illumination optical unit It is characterized by being hermetically sealed.
With this configuration, the incident side portion of the housing that holds the projection lens is sealed by entering the housing of the illumination optical unit, can maintain a dustproof effect, and the incident side portion of the housing that holds the projection lens Heat can be dissipated from the illumination optical unit.

(Aspect C)
In (Aspect B), a projection optical unit having the projection lens is provided, and a heat conductive sheet or a heat conductive grease is used as a heat dissipation means between the projection optical unit and the illumination optical unit. is there.
With this configuration, the heat of the projection optical unit is radiated from the heat radiating means using the heat conductive sheet or the heat conductive grease, and the heat radiating effect is enhanced.

(Aspect D)
In (Aspect B) or (Aspect C), an intake port 53 for taking in outside air and an exhaust port 54 for exhausting air in the image projection apparatus main body are provided in a part of the casing of the image projection apparatus main body, and the intake port The flow path of the air flowing from the exhaust toward the exhaust port is formed to pass through the illumination optical unit.
According to such a configuration, the air taken in from the intake port passes through the illumination optical unit, takes heat from the illumination optical unit to which the heat of the projection optical unit is transmitted, and the heated air is discharged from the exhaust port. Thereby, the cooling efficiency of the illumination optical unit is increased.

(Aspect E)
In (Aspect C) or (Aspect D), a flow path of air flowing from the intake port toward the exhaust port is formed so as to pass through the projection optical unit.
With this configuration, the air taken in from the intake port touches the projection optical unit and takes heat away from the projection optical unit, and the heated air is discharged from the exhaust port. Thereby, the cooling efficiency of the projection optical unit is increased.

(Aspect F)
In any one of (Aspect B) to (Aspect E), the casing constituting the illumination optical unit is formed of aluminum or a material containing aluminum.
According to this aspect, the heat dissipation efficiency of the illumination optical unit is enhanced by forming the casing of the illumination optical unit with aluminum having a high thermal conductivity or a material containing aluminum.

(Aspect G)
In any one of (Aspect B) to (Aspect E), the casing constituting the illumination optical unit is formed of copper or a material containing copper.
According to this aspect, the heat radiation efficiency of the illumination optical unit is enhanced by forming the casing of the illumination optical unit with copper having a high thermal conductivity or a material containing copper.

(Aspect H)
In any one of (Aspect A) to (Aspect G), a part or all of a portion for holding the projection lens is formed of aluminum or a material containing aluminum.
According to this aspect, by forming part or all of the member that holds the projection lens with aluminum or a material containing aluminum, the heat dissipation efficiency of the member that holds the projection lens is improved, and the projection lens is good Can be cooled to.

DESCRIPTION OF SYMBOLS 1 Projector 10 Light source unit 11 Light source 20 Projection image generation unit 21 DMD
30 illumination optical unit 31 color wheel 31a motor 32 light tunnel 33 relay lens 34 plane mirror 35 concave mirror 40 projection optical unit 41 barrel 42 projection lens 43 folding mirror 44 curved mirror 45 dustproof glass 46 mirror bracket 47 free mirror bracket 48 mirror holder 49 Glass holding member 50 Projection lens fixing bracket 51 Radiation cover 51a Radiation fin 51b Groove 51c Opening 52 Thermal conduction sheet 53 Intake port 54 Exhaust port 55 Exhaust fan 56 Ventilation port 61 Transmission glass 62 Operation unit 63 Focus lever 101 Projection surface

Japanese Patent No. 4986019

Claims (8)

In an image projection apparatus that projects light of a projection image generated by an image generation element based on image data using light of a light source onto a projection surface via at least one projection lens,
An outer peripheral portion of the casing is exposed between the incident-side portion on which the projection image light is incident in the long cylindrical casing that holds the projection lens and the emission-side portion on which the projection image light is emitted in the casing. In this state, the incident side portion and the emission side portion of the casing are sealed so as to transmit the projection image light, respectively, and the outside air taken into the image projection apparatus flows to the outer peripheral portion of the casing in the exposed state. An image projection apparatus characterized by that. The image projection apparatus according to claim 1,
An illumination optical unit that guides light from the light source to the image generation element is provided, and the illumination optical unit is hermetically sealed with a light incident side portion of the housing placed in a housing constituting the illumination optical unit. An image projection apparatus characterized by the above. The image projection apparatus according to claim 2,
An image projection apparatus comprising a projection optical unit having the projection lens, wherein a heat conductive sheet or a heat conductive grease is used as a heat radiating means between the projection optical unit and the illumination optical unit. In the image projection device according to claim 2 or 3,
An intake port for taking in outside air and an exhaust port for exhausting air in the image projection apparatus main body are provided in a part of the casing of the image projection apparatus main body,
An image projection apparatus, wherein a flow path of air flowing from the intake port toward the exhaust port is formed so as to pass through the illumination optical unit. In the image projection device according to claim 3 or 4,
An image projection apparatus, wherein a flow path of air flowing from the intake port toward the exhaust port is formed so as to pass through the projection optical unit. The image projection apparatus according to any one of claims 2 to 5,
An image projection apparatus, wherein the casing constituting the illumination optical unit is made of aluminum or a material containing aluminum. The image projection apparatus according to any one of claims 2 to 5,
An image projection apparatus, wherein the casing constituting the illumination optical unit is made of copper or a material containing copper. The image projection apparatus according to any one of claims 1 to 7,
Part or all of a housing for holding the projection lens is formed of aluminum or a material containing aluminum.

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