JP2009042329A - Image projection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently cool a projection lens barrel and other members to be cooled. <P>SOLUTION: The image projection device has the projection lens barrel 5, the members to be cooled 61R, 61G and 61B other than the projection lens barrel, and a first cooling fan 12A. The first cooling fan supplies air taken in from a first inlet 13a facing a part arranged on the inside of the device of the projection lens barrel and from a second inlet 21a facing the outside of the device of the projection lens barrel to the members to be cooled. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image projection apparatus such as a liquid crystal projector, and more particularly to a cooling structure that cools the inside of the apparatus with cooling air.

  As the brightness of an image projection apparatus (hereinafter referred to as a projector) increases, the amount of light incident on the projection lens barrel from the light source lamp increases, so that the temperature of the projection lens barrel tends to increase.

  When the temperature of the projection lens barrel rises, the refractive index of the lens in the lens barrel changes or thermal expansion of the lens barrel occurs compared to the state where the temperature of the projection lens barrel is still low at the beginning of lamp lighting. Therefore, it leads to deterioration of optical performance. Therefore, it is necessary to make corrections according to the rise in the temperature of the projection lens barrel.

  In addition, the amount of light emitted per unit area of components other than the projection lens barrel, for example, an image modulation element such as a liquid crystal panel is increasing, and the temperature rise of these components is also a problem. In addition, since the distance between the parts is reduced with the miniaturization of the projector, it is difficult to cool these parts.

In the projector disclosed in Patent Document 1, the liquid crystal panel, the polarizing plate, the polarization beam splitter, and the light source lamp are cooled by using two cooling fans arranged around the projection lens barrel.
Japanese Patent No. 3528862

  However, the conventional projector disclosed in Patent Document 1 does not employ a configuration for cooling the periphery of the projection lens barrel itself. Therefore, it is impossible to suppress the deterioration of the optical performance accompanying the temperature rise of the projection lens barrel.

  Further, in the projector disclosed in Patent Document 1, since the two cooling fans take in air from one air inlet provided in the housing of the apparatus, the air intake resistance is large. For this reason, there exists a possibility of causing the increase in the rotation speed of a cooling fan, and the increase in the noise accompanying this.

  The present invention provides an image projection apparatus capable of efficiently cooling a projection lens barrel and other members to be cooled.

  An image projection apparatus according to an aspect of the present invention includes a projection lens barrel, a member to be cooled other than the projection lens barrel, and a first cooling fan. The first cooling fan takes in air taken in from the first air inlet that faces a portion of the projection lens barrel disposed inside the apparatus and the second air inlet that faces the outside of the apparatus. Is supplied to the member to be cooled.

  Note that an image display system including the image projection apparatus and an image supply apparatus that supplies image information to the image projection apparatus also constitutes another aspect of the present invention.

  In the invention, the projection lens barrel is cooled by the air sucked into the first air inlet. Thereby, the temperature rise of the projection lens barrel and the accompanying deterioration in optical performance can be suppressed. Further, the air cooled from the second intake port is mixed with the air that has cooled the projection lens barrel, and the air whose temperature has been lowered is supplied to the member to be cooled. Thereby, a to-be-cooled member can be cooled efficiently. In addition, since the air is taken into the fan through the two intake ports, the intake resistance can be reduced. Therefore, the number of fan rotations can be reduced, and the apparatus can be quieted.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(Overall configuration of projector)
FIG. 1 shows the configuration of a liquid crystal projector (image projection apparatus) that is Embodiment 1 of the present invention.

  In this figure, reference numeral 1 denotes a light source lamp (hereinafter simply referred to as a lamp), and a high-pressure mercury discharge lamp is used in this embodiment. However, as the light source lamp 1, a discharge lamp (for example, a halogen lamp, a xenon lamp, or a metal halide lamp) other than the high-pressure mercury discharge lamp may be used.

  2 is a lamp holder for holding the lamp 1, 3 is explosion-proof glass, and 4 is a glass presser. α is an illumination optical system that converts the luminous flux from the lamp 1 into a parallel luminous flux having a uniform brightness distribution, β is a color separation of the light from the illumination optical system α, and is applied to a liquid crystal panel for RGB, which will be described later. A color separation / synthesis optical system for guiding and color-combining light from the liquid crystal panel.

  Reference numeral 5 denotes a projection lens barrel that projects light (image) from the color separation / synthesis optical system β onto a screen (projected surface) (not shown). A projection optical system, which will be described later, is housed in the projection lens barrel 5.

  Reference numeral 6 denotes an optical box that houses the lamp 1, the illumination optical system α, and the color separation / synthesis optical system β and to which the projection lens barrel 5 is fixed. The optical box 6 is formed with a lamp case 6 a surrounding the lamp 1.

  Reference numeral 7 denotes an optical box lid that covers the optical box 6 with the illumination optical system α and the color separation / synthesis optical system β accommodated therein. Reference numeral 8 denotes a PFC power supply board that creates a DC power supply from a commercial power supply to each board. Reference numeral 9 denotes a power supply filter board. Reference numeral 10 denotes a ballast power supply board that operates with the PFC power supply board 8 to drive the lamp 1 to light.

  Reference numeral 11 denotes a control board that performs driving of the liquid crystal panel and lighting control of the lamp 1 by electric power from the PFC power supply board 8. 12A and 12B are first and second for cooling optical elements such as a liquid crystal panel and a polarizing plate in the color separation / synthesis optical system β by sucking air from an air inlet 21a of the lower exterior case 21 described later. It is an optical system cooling fan. Reference numeral 13 denotes a first RGB duct that guides the wind from both optical system cooling fans 12A and 12B to the optical elements in the color separation / synthesis optical system β.

  Reference numeral 70 denotes a first dust removal filter that covers a first air inlet, which will be described later, formed in the first RGB duct 13.

  Reference numeral 14 denotes a lamp cooling fan that sends a blowing air to the lamp 1 to cool the lamp 1. A first lamp duct 15 guides the cooling air to the lamp 1 while holding the lamp cooling fan 14. Reference numeral 16 denotes a second lamp duct that holds the lamp cooling fan 14 and forms a duct together with the first lamp duct 15.

  Reference numeral 17 denotes a power supply cooling fan for cooling air by sucking air from an air inlet 21b provided in the lower exterior case 21 and allowing air to flow through the PFC power supply board 8 and the ballast power supply board 10. Reference numeral 18 denotes an exhaust fan, which discharges hot air that has been sent from the lamp cooling fan 14 to the lamp 1 and has cooled it, from an exhaust port 24a formed in a second side plate B24 described later.

  The lower exterior case 21 houses the lamp 1, the optical box 6, the power supply system boards 8 to 10, the control board 11, and the like. Reference numeral 22 denotes an upper outer case for covering the lower outer case 21 with the optical box 6 and the like stored therein. Reference numeral 23 denotes a first side plate, which closes a side opening formed by the outer cases 21 and 22 together with the second side plate 24. The lower exterior case 21 has the above-described intake ports 21a and 21b, and the second side plate 24 has the above-described exhaust port 24a. The lower exterior case 21, the upper exterior case 22, the first side plate 23, and the second side plate 24 constitute a housing of the projector.

  Reference numeral 25 denotes an IF board on which a connector for taking in various signals is mounted. Reference numeral 26 denotes an IF reinforcing plate attached to the inside of the first side plate 23.

  Reference numeral 27 denotes an exhaust duct for guiding the exhaust heat from the lamp 1 to the exhaust fan 18 so as not to diffuse the exhaust air into the housing.

  Reference numeral 28 denotes a lamp lid. The lamp lid 28 is detachably disposed on the bottom surface of the lower exterior case 21 and is fixed by a screw (not shown). Reference numeral 29 denotes a set adjustment leg. The set adjustment leg 29 is fixed to the lower exterior case 21, and the height of the leg part 29a can be adjusted. The tilt angle of the projector can be adjusted by adjusting the height of the leg 29a.

  Reference numeral 30 denotes an RGB intake plate for holding a second dust removal filter 71 attached to the outside of the intake port 21a of the lower exterior case 21.

  Reference numeral 31 denotes a prism base that holds the color separation / synthesis optical system β. Reference numeral 32 denotes a box side cover having a duct-shaped portion for guiding cooling air from the first and second optical system cooling fans 12A and 12B in order to cool the optical elements and the liquid crystal panel in the color separation / synthesis optical system β. Reference numeral 33 denotes a second RGB duct that forms a duct together with the box side cover 32.

  Reference numeral 34 denotes an RGB substrate connected to the control substrate 11 to which a flexible substrate extending from a liquid crystal panel disposed in the color separation / synthesis optical system β is connected.

(Optical configuration)
Next, the configuration of the optical system including the lamp 1, the illumination optical system α, the color separation / synthesis optical system β, and the projection lens barrel (projection optical system) 5 will be described with reference to FIG. 2A shows a horizontal section of the optical system, and FIG. 2B shows a vertical section.

  In the figure, reference numeral 41 denotes a discharge arc tube (hereinafter simply referred to as an arc tube) that emits white light in a continuous spectrum. Reference numeral 42 denotes a reflector having a concave mirror that condenses light from the arc tube 41 in a predetermined direction. The light source lamp 1 is constituted by the arc tube 41 and the reflector 42.

  Reference numeral 43a denotes a first cylinder array in which a plurality of cylindrical lens cells having refractive power in the horizontal direction shown in FIG. 43b is a second cylinder array having a plurality of cylindrical lens cells corresponding to the individual lens cells of the first cylinder array 43a. 44 is an ultraviolet absorption filter, and 45 is a polarization conversion element that converts non-polarized light into predetermined polarized light.

  Reference numeral 46 denotes a front compressor composed of a cylindrical lens having a refractive power in the vertical direction shown in FIG. Reference numeral 47 denotes a reflection mirror for bending the optical axis from the lamp 1 by approximately 90 degrees (more specifically, 88 degrees).

  43c is a third cylinder array in which a plurality of cylindrical lens cells having refractive power in the vertical direction are arranged. 43d is a fourth cylinder array having a plurality of cylindrical lens arrays corresponding to individual lens cells of the third cylinder array 43c.

  Reference numeral 50 denotes a color filter for returning the color in a specific wavelength region to the lamp 1 in order to adjust the color coordinates to a predetermined value. Reference numeral 48 denotes a condenser lens. Reference numeral 49 denotes a rear compressor composed of a cylindrical lens having a refractive power in the vertical direction. The illumination optical system α is configured as described above.

  58 is a dichroic mirror that reflects light in the wavelength region of blue (B: for example 430 to 495 nm) and red (R: for example 590 to 650 nm) and transmits light in the wavelength region of green (G: for example 505 to 580 nm). is there. 59 is an incident side polarizing plate for G in which a polarizing element is bonded to a transparent substrate, and transmits only P-polarized light. Reference numeral 60 denotes a first polarization beam splitter that transmits P-polarized light and reflects S-polarized light on a polarization separation surface constituted by a multilayer film.

  61R, 61G, and 61B are a reflective liquid crystal panel for red, a reflective liquid crystal panel for green, and a reflective liquid crystal panel for blue as light modulation elements (or image forming elements) that reflect incident light and modulate the image, respectively. is there. 62R, 62G, and 62B are a quarter wavelength plate for red, a quarter wavelength plate for green, and a quarter wavelength plate for blue, respectively.

  A trimming filter 64a returns orange light to the lamp 1 in order to increase the color purity of the R light. Reference numeral 64b denotes an incident-side polarizing plate for RB in which a polarizing element is attached to a transparent substrate and transmits only P-polarized light.

  65 is a color selective phase difference plate that converts the polarization direction of the R light by 90 degrees and does not convert the polarization direction of the B light. Reference numeral 66 denotes a second polarization beam splitter that transmits P-polarized light and reflects S-polarized light on the polarization separation surface.

  Reference numeral 68B denotes a B-use exit side polarizing plate (polarizing element) that rectifies only the S-polarized component of the B light. 68G is a G output-side polarizing plate that transmits only the S-polarized light component of the G light. Reference numeral 69 denotes a dichroic prism that transmits R light and B light and reflects G light.

  The above dichroic mirror 58 to dichroic prism 69 constitute a color separation / synthesis optical system β.

  In this embodiment, the polarization conversion element 45 converts P-polarized light to S-polarized light. The P-polarized light and S-polarized light described here are described with reference to the polarization direction of light in the polarization conversion element 45. On the other hand, the light incident on the dichroic mirror 58 is assumed to be P-polarized light considering the polarization directions in the first and second polarization beam splitters 60 and 66 as a reference. That is, in this embodiment, the light emitted from the polarization conversion element 45 is S-polarized light, but when the same S-polarized light is incident on the dichroic mirror 58, it is defined as P-polarized light.

(Optical action)
Next, the optical action will be described.

  Light emitted from the arc tube 41 is collected in a predetermined direction by the reflector 42. The reflector 42 has a parabolic concave mirror, and light from the focal position of the paraboloid becomes a light beam parallel to the symmetry axis of the paraboloid. However, since the light source from the arc tube 41 is not an ideal point light source and has a finite size, the condensed light flux includes many light components that are not parallel to the symmetry axis of the paraboloid. ing. These light beams are incident on the first cylinder array 43a. The light beam incident on the first cylinder array 43a is divided into a plurality of light beams corresponding to the number of cylinder lens cells and collected to form a plurality of strip-shaped light beams arranged in the vertical direction. The plurality of split light beams pass through the ultraviolet absorption filter 44 and the second cylinder array 43b to form a plurality of light source images in the vicinity of the polarization conversion element 45.

  The polarization conversion element 45 has a polarization separation surface, a reflection surface, and a half-wave plate. A plurality of light beams are incident on a polarization separation surface corresponding to each column, and are divided into a P-polarized component that transmits the light and an S-polarized component that is reflected there. The reflected S-polarized component is reflected by the reflecting surface and is emitted in the same direction as the P-polarized component. On the other hand, the P-polarized component transmitted through the polarization splitting surface is transmitted through the half-wave plate and converted into the same polarized component as the S-polarized component. Thus, a plurality of light beams having the same polarization direction are emitted.

  The plurality of light beams that have undergone polarization conversion are emitted from the polarization conversion element 45, compressed by the front compressor 46, reflected by the reflection mirror 47, and incident on the third cylinder array 43 c.

  The light beam incident on the third cylinder array 43c is divided into a plurality of light beams corresponding to the number of cylinder lens cells and collected to form a plurality of strip-shaped light beams arranged in the horizontal direction. The plurality of split light beams enter the rear compressor 49 via the fourth cylinder array 43d and the condenser lens 48.

  By the optical action of the front compressor 46, the condenser lens 48, and the rear compressor 49, rectangular images formed by a plurality of light beams overlap each other to form a rectangular uniform brightness illumination area. Reflective liquid crystal panels 61R, 61G, and 61B are disposed in this illumination area.

  The light converted to S-polarized light by the polarization conversion element 45 enters the dichroic mirror 58. Hereinafter, the optical path of the G light transmitted through the dichroic mirror 58 will be described.

  The G light transmitted through the dichroic mirror 58 enters the incident side polarizing plate 59. Even after being decomposed by the dichroic mirror 58, the G light remains P-polarized light (S-polarized light when the polarization conversion element 45 is used as a reference). The G light exits from the incident-side polarizing plate 59, then enters the first polarizing beam splitter 60 as P-polarized light, passes through the polarization separation surface, and reaches the G reflective liquid crystal panel 61G.

  Here, an image supply device 80 such as a personal computer, a DVD player, or a TV tuner is connected to the IF board 25 of the projector. The control board 11 drives the reflective liquid crystal panels 61R, 61G, and 61B based on the image information input from the image supply device 80, and forms an original image for each color on them. Thus, the light incident on each reflective liquid crystal panel is reflected and modulated (image modulation) according to the original image. The image supply apparatus 80 and the projector constitute an image display system.

  In the G reflective liquid crystal panel 61G, the G light is image-modulated and reflected. The P-polarized component of the image-modulated G light is again transmitted through the polarization separation surface of the first polarization beam splitter 60, returned to the light source side, and removed from the projection light. On the other hand, the S-polarized component of the image-modulated G light is reflected by the polarization separation surface of the first polarization beam splitter 60 and travels toward the dichroic prism 69 as projection light.

  At this time, in a state where all the polarization components are converted to P-polarized light (in a state where black is displayed), a quarter-wave plate 62G provided between the first polarizing beam splitter 60 and the G-use reflective liquid crystal panel 61G. The slow axis is adjusted in a predetermined direction. Thereby, the influence of the disturbance of the polarization state which generate | occur | produces with the 1st polarizing beam splitter 60 and the reflective liquid crystal panel 61G for G can be restrained small.

  The G light emitted from the first polarization beam splitter 60 enters the dichroic prism 69 as S-polarized light, is reflected by the dichroic film surface of the dichroic prism 69, and reaches the projection lens barrel 5.

  On the other hand, the R light and B light reflected by the dichroic mirror 58 enter the trimming filter 64a. R light and B light are still P-polarized light after being decomposed by the dichroic mirror 58. Then, after the orange light component is cut by the trimming filter 64a, the R light and the B light are transmitted through the incident side polarizing plate 64b and are incident on the color selective phase difference plate 65.

  The color-selective phase difference plate 65 has an action of rotating only the polarization direction of the R light by 90 degrees, so that the R light is incident on the second polarization beam splitter 66 as S-polarized light and the B light is incident on P-polarized light.

  The R light incident on the second polarization beam splitter 66 as S-polarized light is reflected by the polarization separation surface of the second polarization beam splitter 66 and reaches the R-use reflective liquid crystal panel 61R. The B light incident on the second polarization beam splitter 66 as P-polarized light is transmitted through the polarization separation surface of the second polarization beam splitter 66 and reaches the B-use reflective liquid crystal panel 61B.

  The R light incident on the R reflective liquid crystal panel 61R is image-modulated and reflected. The S-polarized component of the image-modulated R light is reflected again by the polarization separation surface of the second polarization beam splitter 66, returned to the light source side, and removed from the projection light. On the other hand, the P-polarized component of the image-modulated R light passes through the polarization separation surface of the second polarization beam splitter 66 and travels toward the dichroic prism 69 as projection light.

  The B light incident on the B-use reflective liquid crystal panel 61B is image-modulated and reflected. The P-polarized component of the image-modulated B light is transmitted again through the polarization separation surface of the second polarization beam splitter 66 and returned to the light source side, and is removed from the projection light. On the other hand, the S-polarized component of the image-modulated B light is reflected by the polarization separation surface of the second polarization beam splitter 66 and travels toward the dichroic prism 69 as projection light.

  At this time, by adjusting the slow axes of the quarter-wave plates 62R and 62B provided between the second polarizing beam splitter 66 and the R and B reflective liquid crystal panels 61R and 61B, As in the case, the adjustment in the black display state of each of the R and B lights can be performed.

  The R light and B light that are combined into one light beam and emitted from the second polarization beam splitter 66 are analyzed by the exit-side polarizing plate 68B and enter the dichroic prism 69. Further, the R light is transmitted through the exit-side polarizing plate 68 </ b> B as P-polarized light and enters the dichroic prism 69.

  By being analyzed by the exit-side polarizing plate 68B, the B light is ineffective generated by the B light passing through the second polarizing beam splitter 66, the B reflective liquid crystal panel 61B, and the quarter wavelength plate 62B. The light is cut from the components.

  The R light and B light incident on the dichroic prism 69 pass through the dichroic film surface and are combined with the G light reflected by the dichroic film surface to reach the projection lens 5.

  The combined R, G, B light is enlarged and projected onto a projection surface such as a screen by the projection lens 5.

  The optical path described above is when the reflective liquid crystal panel is in the white display state. Hereinafter, the optical path when the reflective liquid crystal panel is in the black display state will be described.

  First, the optical path of G light will be described. The P-polarized light of the G light that has passed through the dichroic mirror 58 enters the incident-side polarizing plate 59, then enters the first polarizing beam splitter 60, is transmitted through the polarization separation surface, and is transmitted to the G reflective liquid crystal panel 61G. And so on. However, since the reflective liquid crystal panel 61G is in the black display state, the G light is reflected without being image-modulated. For this reason, even after being reflected by the reflective liquid crystal panel 61G for G, the G light remains P-polarized light. Therefore, the G light again passes through the polarization separation surface of the first polarization beam splitter 60, passes through the incident-side polarizing plate 59, returns to the light source side, and is removed from the projection light.

  Next, the optical paths of R light and B light will be described. The P-polarized light of R light and B light reflected by the dichroic mirror 58 is incident on the incident side polarizing plate 64b. Then, after exiting from the incident side polarizing plate 64 b, the light enters the color selective phase difference plate 65. Since the color-selective phase difference plate 65 has an action of rotating only the polarization direction of the R light by 90 degrees, the R light is incident on the second polarization beam splitter 66 as S-polarized light and the B light is incident on P-polarized light.

  The R light incident on the second polarization beam splitter 66 as S-polarized light is reflected by the polarization separation surface and reaches the R-use reflective liquid crystal panel 61R. The B light incident on the second polarization beam splitter 66 as P-polarized light passes through the polarization separation surface and reaches the B-use reflective liquid crystal panel 61B.

  Here, since the R reflective liquid crystal panel 61R is in a black display state, the R light incident on the R reflective liquid crystal panel 61R is reflected without being image-modulated. For this reason, even after being reflected by the reflective liquid crystal panel 61R for R, the R light remains S-polarized light. Accordingly, the R light is reflected again by the polarization separation surface of the second polarization beam splitter 66, passes through the incident-side polarizing plate 64b, returns to the light source side, and is removed from the projection light. Thereby, black display is performed.

  On the other hand, the B light incident on the B reflective liquid crystal panel 61B is reflected without being image-modulated because the B reflective liquid crystal panel 61B is in the black display state. For this reason, even after being reflected by the reflective liquid crystal panel 61B for B, the B light remains P-polarized light. Therefore, the B light again passes through the polarization separation surface of the second polarizing beam splitter 66, is converted to P-polarized light by the color-selective retardation plate 65, passes through the incident-side polarizing plate 64b, and is returned to the light source side. Removed from the projected light.

(Cooling structure)
Next, a cooling configuration in the projector of this embodiment will be described with reference to FIG. As described above, five projectors 12A, 12B, 14, 17, and 18 are accommodated in the projector, and each cooling target is cooled by flowing an air flow through a plurality of flow paths described below.

  In the flow path B indicated by a solid line arrow in FIG. 3, the air in the housing sucked by the lamp cooling fan 14 is sent to the lamp 1 as cooling air through the ducts 15 and 16. The air flow that has cooled the lamp 1 is guided to the exhaust box 27 and exhausted to the outside of the housing by the exhaust fan 18.

  In a flow path A indicated by a dotted arrow in FIG. 3, first and second cooling fans 12 </ b> A and 12 </ b> B (12 </ b> B is disposed on the lower side of the projection lens barrel 5) from the lower inlet 21 a of the projection lens barrel 5. The air sucked in from the outside of the housing flows in. The cooling air generated by the air flow cools the optical element of the color separation / synthesis system β disposed in the optical box 6. Most of the cooling air flows toward the PFC power supply board 8 and the ballast power supply board 10 adjacent to the optical box 6, and after cooling the electrical components mounted on the boards 9, 10, the exhaust fan 18 and the power supply The cooling fan 17 discharges the outside of the housing.

  Further, in the flow path C indicated by the one-dot chain line arrow in FIG. 3, the air sucked from the intake port 21 b (not shown in FIG. 3) of the lower exterior case 21 flows. The cooling air by the air flow is guided to the ballast power supply board 10 and the PFC power supply board 8 by the suction force of the power supply cooling fan 17 or the exhaust fan 18 together with the air in the housing. Then, after these substrates 8 and 10 are cooled, they are discharged out of the housing by the power cooling fan 17 and the exhaust fan 18.

  The cooling structure of the projection lens barrel 5 and the color separation / synthesis optical system β in the projector configured as described above will be described in detail with reference to FIGS. FIG. 5 shows a state seen from the lower surface side of a part of the cooling structure disassembled in FIG.

  In FIG. 4, a first optical system cooling fan (hereinafter simply referred to as a first cooling fan) 12A is sandwiched and held by a first RGB duct 13 as a duct member and a second RGB duct 33 shown in FIG. The The first cooling fan 12 </ b> A takes in air W <b> 1 from a first air inlet 13 a provided at the upper part of the first RGB duct 13.

  Here, the first air inlet 13a is formed so as to face the outer peripheral surface (side surface) which is a portion of the projection lens barrel 5 disposed inside the housing (device). More specifically, the first air inlet 13 a has a curved opening shape along a part of the outer peripheral surface of the projection lens barrel 5.

  In addition, an opening 13b is formed on the bottom surface of the first RGB duct 13 so as to face the exhaust surface of a second optical system cooling fan (hereinafter simply referred to as a second cooling fan) 12B. The intake surface of the second cooling fan 12B is opposed to an intake port (second intake port) 21a provided on the bottom surface of the lower exterior case 21 and facing the outside of the housing.

  The first RGB duct 13 includes a first duct that guides air (outside air) W2 outside the housing that has flowed from the second air inlet 21a through the second cooling fan 12B and the opening 13b to the first cooling fan 12A. A portion 13c is formed.

  Further, the first RGB duct 13 and the second RGB duct 33 together with the second duct portion 13d and the third duct portion constituting a duct for guiding air toward the color separation / synthesis optical system β (that is, toward the member to be cooled). The duct portion 13e is provided. The second duct portion 13d is connected to a duct formed by combining the second RGB duct 33 and the box side cover 32, so that the cooling air from the first cooling fan 12A is color-separated and combined optical system. Guide to β (reflection type liquid crystal panels 61R and 61B, quarter wave plates 62R and 62B). The third duct portion 13e is connected to a duct formed together with the optical box 6 so that the cooling air W4 from the second cooling fan 12B is converted into the color separation optical system β (incident side polarizing plate 64b, color). Selective retardation plate 65, reflection type liquid crystal panel 61G, and ¼ wavelength plate 62G).

  In such a configuration, the air W1 flows along the outer peripheral surface of the projection lens barrel 5 by the suction force of the first cooling fan 12A to cool the barrel 5, and then is sucked into the first air inlet 13a. It is. This is indicated by an arrow D in FIG. Thereby, it is possible to suppress the deterioration of the optical performance due to the temperature rise of the projection lens barrel 5.

  Further, inside the first RGB duct 13, low temperature (for example, room temperature) outside air W <b> 2 taken in through the air inlet 21 a, the second cooling fan 12 </ b> B, the opening 13 b, and the duct portion 13 c cools the projection lens barrel 5. It is mixed with the air W1 whose temperature has increased. As a result, the temperature of the air W3 supplied from the first cooling fan 12A to the color separation / synthesis optical system β through the duct-shaped portion 13d can be made lower than the temperature of the air W1.

  The air W3 having a low temperature efficiently cools the members constituting the color separation / synthesis optical system β (cooled members other than the projection lens barrel). The members to be cooled include light modulation elements, in other words, reflective liquid crystal panels 61R, 61G, 61B as image modulation elements, and quarter-wave plates 62R, 62G, 61B. In addition, the polarizing plates 59, 64b, 68B, 68G, the color selective phase difference plate 65, the trimming filter 64a, and the like may be cooled.

  In the present embodiment, main intake ports 13a and 21a are provided for each of the first cooling fan 12A and the second cooling fan 12B.

  If the first cooling fan 12A and the second cooling fan 12B perform intake only from the intake port 21a, the two fans will compete for the intake air. As a result, the intake resistance increases, and it is necessary to increase the rotational speed of each fan in order to obtain the necessary wind speed and air volume. This increases noise.

  On the other hand, in the present embodiment, the first cooling fan 12A mainly sucks air from the adjacent first air inlet 13a, thereby reducing air contention between the two cooling fans 12A and 12B at the air inlet 21a. can do. Therefore, both the rotation speeds of the first and second cooling fans 12A and 12B can be reduced, and the projector can be made silent.

  A first dust removal filter 70 is disposed at the first air inlet 13a. A second dust removal filter 71 is disposed at the second air inlet 21a (not shown in FIG. 5). The first dust removal filter 70 is held by a claw portion provided around the first air inlet 13 a in the first RGB duct 13. The second dust removal filter 71 is sandwiched between the louver portion provided at the intake port 21 a and the RGB intake plate 30.

  By providing these dust removal filters 70 and 71, it is possible to prevent dust and the like from entering the color separation / synthesis optical system β where dust and dust are particularly problematic.

  As described above, the first RGB duct 13 includes the first air inlet 13a, the opening 13b, the first duct portion 13c, and the second duct portion 13d, and further includes the first dust removal filter 70. It also has a holding function. By using such a multifunctional first RGB duct 13, the number of parts of the cooling structure can be reduced.

  FIG. 6 shows a cooling structure of the projection lens barrel 5 and the color separation / synthesis optical system β (optical unit) in the liquid crystal projector that is Embodiment 2 of the present invention. The present embodiment corresponds to a configuration in which the second cooling fan 12B is eliminated from the cooling structure of the first embodiment (FIGS. 4 and 5). In the present embodiment, the same components and components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description is omitted.

  The air W1 flows along the outer peripheral surface of the projection lens barrel 5 by the suction force of the first cooling fan 12A to cool the barrel 5, and is then sucked into the first air inlet 13a. Thereby, it is possible to suppress the deterioration of the optical performance due to the temperature rise of the projection lens barrel 5.

  Further, inside the first RGB duct 13, the low-temperature outside air W <b> 2 taken through the air inlet 21 a, the opening 13 b, and the duct portion 13 c is mixed with the air W <b> 1 whose temperature has risen by cooling the projection lens barrel 5. As a result, the temperature of the air W3 supplied from the first cooling fan 12A to the color separation / synthesis optical system β through the duct-shaped portion 13d can be made lower than the temperature of the air W1.

  The air W3 having a low temperature efficiently cools the members (cooled members) constituting the color separation / synthesis optical system β described in the first embodiment.

  In the present embodiment, since the intake air to the first cooling fan 12A is performed through the two intake ports 13a and 21a, the intake resistance can be reduced as compared with the case where intake is performed through the single intake port. Therefore, the number of rotations of the first cooling fan 12A can be reduced, and the projector can be silenced.

  Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention. For example, in each of the above embodiments, the case where the air inlet 21a as the second air inlet is formed on the bottom surface of the housing has been described, but the second air inlet may be formed on the side surface of the housing.

  Further, a transmissive liquid crystal panel or a digital micromirror device (DMD) may be used instead of the reflective liquid crystal panel.

1 is an exploded perspective view of a projector that is Embodiment 1 of the present invention. FIG. 2 is a plan view and a side view illustrating an optical configuration of a projector according to a first embodiment. FIG. 3 is a plan view showing a flow of cooling air of the projector according to the first embodiment. 2 is an exploded perspective view showing a cooling structure in Embodiment 1. FIG. 2 is a bottom view showing a cooling structure in Embodiment 1. FIG. FIG. 6 is an exploded perspective view showing a projector cooling structure that is Embodiment 2 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source lamp 5 Projection lens barrel 12A 1st cooling fan 12B 2nd cooling fan 13 1st RGB duct 32 Box side cover 33 2nd RGB duct 59, 64b, 68B, 68G Polarizing plate 61R, 61G, 61B Reflective type liquid crystal panel 62R, 62G, 62B 1/4 wavelength plate 64a Trimming filter 65 Color selective phase difference plate 70, 71 Dust removal filter

Claims (6)

An image projection apparatus for projecting an image,
A projection lens barrel;
A member to be cooled other than the projection lens barrel;
A first cooling fan,
The first cooling fan takes in air taken from a first air inlet that faces a portion of the projection lens barrel disposed inside the apparatus and a second air inlet that faces the outside of the apparatus. Is supplied to the member to be cooled. An optical system that modulates light from a light source by an image modulation element and guides the light to the projection lens barrel;
The image projection apparatus according to claim 1, wherein the member to be cooled is a member constituting the optical system.   A first duct that holds the first cooling fan, guides the air taken in from the second air inlet to the first cooling fan, and the first cooling fan; The image projection apparatus according to claim 1, further comprising a duct member having a second duct portion that guides air from the fan to the member to be cooled.   4. The apparatus according to claim 1, further comprising a second cooling fan that takes in air outside the apparatus from the second air inlet and supplies the air to the first cooling fan. 5. Image projection device.   The first and second cooling fans are held, and the first intake port and the first air that is taken in from the second intake port by the second cooling fan are guided to the first cooling fan. 5. The image projection apparatus according to claim 4, further comprising: a duct member having a first duct portion and a second duct portion that guides air from the first cooling fan toward the member to be cooled. An image projection device according to any one of claims 1 to 5,
An image display system comprising: an image supply device that supplies image information to the image projection device.