JP4630563B2 - Projection display device and image projection system - Google Patents

Description

  The present invention relates to a projection display device (a projection image display device such as a transmissive liquid crystal projector or a reflective liquid crystal projector) and an image projection system using the same. In particular, it relates to light source cooling of a projection display device.

  Conventionally, metal halide lamps, high-pressure mercury lamps, halogen lamps, xenon lamps and other discharge lamps have been used as light source lamps in projection-type image display devices. It is. In general, this cooling method employs an air-cooling method, that is, the cooling of the lamp is performed by using the flow of wind by an axial fan, a sirocco fan, etc., and discharging the wind to the outside of the apparatus. .

  The purpose of this lamp cooling is to (1) maintain the luminous efficiency of the lamp arc tube and prevent deterioration, and (2) cool the lamp reflector itself to reduce the radiant heat from the lamp reflector surface and discharge it outside the device. Two are the main purposes.

  On the other hand, there are many cases in which an optical member (including a projection lens) is arranged close to a lamp in order to cope with downsizing of products in recent years or due to an optical configuration. In Patent Document 1, the lamp arc tube is intensively cooled by a fan provided in the gap between the lamp and the projection lens, and the lamp reflector itself is cooled by using the suction force of the exhaust fan provided on the opposite side. A configuration is disclosed in which radiant heat from the lamp reflector surface is reduced and discharged outside the apparatus.

Further, Patent Document 2 discloses a configuration in which a cooling fan is provided in a gap between a lamp and a projection lens / color separation / synthesis optical system as an example.
JP 2000-221599 A JP 2003-131166 A

  However, in the configuration of Patent Document 1, the fan provided in the gap between the lamp and the projection lens intensively cools the lamp arc tube, and the lamp reflector is cooled by sucking the exhaust fan provided on the opposite side. It is done using power. If the calorific value of the lamp itself is very large, in this configuration, the lamp reflector is not sufficiently cooled, and the surface of the lamp reflector is heated. Then, the radiant heat from the lamp reflector surface is transmitted around the fan for cooling the lamp arc tube, and there is a possibility that the member (projection lens) close to the lamp reflector surface is heated.

  Here, when the member close to the lamp reflector surface is a projection lens, and the glass material of the projection lens is made of plastic, or the projection lens barrel itself is made of plastic, aberration fluctuation due to temperature change, image formation Various projection image performance degradations such as performance degradation, changes in the lens interval due to expansion and contraction of the lens barrel, decentering between lenses, and optical performance degradation due to tilting have occurred.

  Similarly, in the case of a polarizing beam splitter in which the member close to the lamp reflector surface constitutes an optical element, the polarizing beam splitter itself generates heat due to the radiant heat of the lamp, but particularly when the volume of the polarizing beam splitter itself is large. Will cause a temperature distribution in the prism. When this temperature distribution occurs, internal stress is generated in the optical glass material itself, and as a result, birefringence occurs due to the linear elasticity of incident light being elliptically polarized due to photoelasticity, that is, the relationship of reflection and transmission. Collapses (unnecessary polarization components are generated, and reflection and transmission are not performed reliably). As a result, leakage light reaches the projection surface, resulting in a decrease in contrast and a high-quality projection-type image display device. There was a problem that it could not be obtained.

  Similarly, in the case of a liquid crystal panel (image forming element), which is a display unit of a projection type image display device, a member close to the lamp reflector surface, the liquid crystal panel itself generates heat due to lamp radiant heat. The liquid crystal panel is vulnerable to heat, and there is a problem that a high-quality projection type image display device cannot be obtained due to a decrease in contrast, color unevenness and the like caused by vaporization of the liquid crystal itself.

  Therefore, the present invention is to solve the above-described problems, and an object thereof is to provide a projection display device and an image projection system that realize efficient light source cooling so as not to generate optical performance. To do.

In order to achieve the above object, a projection display device according to a first aspect of the present invention is a projection display device that projects light onto a projection surface by a projection optical system using light from a light source. A cooling fan that is disposed between the projection optical system and the light source and sends cooling air from the projection optical system to the light source, and an exterior case that covers the projection optical system, the cooling fan, and the light source. The exterior case has an exhaust port for discharging the cooling air, and the projection optical system, the cooling fan, the light source, and the exhaust port have cooling air from the projection optical system along a straight line. The light source is arranged to flow to the exhaust port through the fan and the light source, and the light source is provided with an arc tube and first and second cutout portions on the cooling fan side and the exhaust port side, respectively. With a reflector The cooling fan sends cooling air to the reflector and also sends cooling air to the arc tube via the first notch, and the cooling air that has cooled the arc tube is from the second notch. It flows to the exhaust port.

A projection display device according to a second aspect of the present invention includes a light source that emits light in a first direction, and an illumination that emits light from the light source in a second direction perpendicular to the first direction. A color separation / synthesis optical system that includes an optical system and an image forming element and emits light from the illumination optical system in a third direction opposite to the first direction; and light from the color separation / synthesis optical system A projection optical system for projecting in the third direction, a cooling fan that is disposed between the projection optical system and the light source, and sends cooling air from the projection optical system to the light source, the projection optical system, and the color An exterior case that covers the decomposition / synthesis optical system, the illumination optical system, the cooling fan, and the light source, and the exterior case includes an exhaust port that discharges the cooling air, and the projection optical system and the cooling The fan, the light source, and the exhaust b It is arranged to flow from an optical system to the exhaust port through the cooling fan and the light source, and the light source includes an arc tube, and first and second notches formed on the cooling fan side and the exhaust port. And the cooling fan sends cooling air to the reflector and sends cooling air to the arc tube via the first notch, and the arc tube The cooled cooling air flows from the second notch to the exhaust gas.

  ADVANTAGE OF THE INVENTION According to this invention, the projection display apparatus and image projection system which implement | achieve efficient light source cooling can be provided so that optical performance may not be generated.

  Embodiments of the present invention will be described below with reference to the drawings.

(Example 1)
FIG. 1 shows a projection type image display device (projection display device) of the present invention.

  In FIG. 1, 1 is a light source lamp, 2 is a lamp holder for holding the lamp 1, α is an illumination optical system for incident light from the lamp 1, and β is for RGB three colors for incident light from the illumination optical system. A color separation / synthesis optical system 3 having a liquid crystal panel 3 is a projection lens barrel that projects light onto a screen (projected surface) (not shown) by receiving light emitted from the color separation / synthesis optical system. The lens barrel 3 houses a projection lens optical system 70 described later. Reference numeral 4 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 3 is fixed. The optical box 4 includes a lamp as a lamp peripheral member surrounding the lamp 1. Case member 4a is formed.

  Reference numeral 5 denotes an optical box lid that covers the optical box 4 with the illumination optical system α and the color separation / synthesis optical system β housed therein, 6 a power source, 7 a ballast power source for lighting the lamp 1, and 8 a power source 6. The circuit board 9 for driving the liquid crystal panel and sending the lighting command of the lamp 1 by the electric power from the liquid crystal panel 9 in the color separation / synthesis optical system β by sucking air from an air inlet 17a of the exterior cabinet 17 to be described later The cooling fan 10 for the optical system for cooling the optical element is a fan duct for sending the wind from the optical cooling fan 9 to the optical element such as a liquid crystal panel in the color separation / synthesis optical system β.

  Reference numeral 11 denotes a cooling fan for a light source lamp for sending a blowing air to the lamp 1 and cooling the lamp 1, and is arranged at a predetermined interval in the gap between the lamp 1 and the projection lens barrel 3. Reference numeral 12 denotes a fan holding base for holding the lamp cooling fan 11, and 13 denotes air that flows through the power supply 6 by sucking air from an air inlet 17 b provided in an exterior cabinet 17 to be described later, and wind that is blown to the ballast power supply 7. Is a cooling fan for a power supply for simultaneously cooling the power supply 6 and the ballast power supply 7, and the wind blown to the ballast power supply 7 by the power supply cooling fan 13 passes through the ballast power supply 7 and will be described later. It is discharged out of the projection type image display device through an exhaust port 17c provided in the exterior cabinet 17 to be operated.

  14 is an exhaust louver for discharging hot air after passing through the lamp 1 by the lamp cooling fan 11 to the outside of the projection type image display device (at this time, the exhaust louver allows the wind to pass outside the device, but the light goes outside the device 15 is a ventilation duct for holding the exhaust louver 14 and for passing hot air after passing through the lamp 1, and 16 is arranged in the gap between the lamp 1 and the lamp case member 4a. The main body portion 16a is a heat shield member that is fixed to the lamp case 4a with a gap to the lamp case member 4a. The heat shield member 16 has an extending portion 16 b that covers the ventilation duct 15 in a state where the exhaust louver 14 is housed in the ventilation duct 15. That is, the extending portion 16b of the heat shield member 16 is formed so as to penetrate into the ventilation duct 15, and forms a ventilation path through which the hot air of the lamp passes between the ventilation duct 15 and the extending portion 16b. Furthermore, the heat shield member 16 is formed of a material having a higher thermal conductivity and a lower thermal radiation rate than the lamp case member 4a as a lamp peripheral member, for example, an aluminum plate.

  Reference numeral 17 denotes an exterior cabinet (lower exterior case) for housing the optical box 4 and the like, and 18 is an exterior cabinet lid (upper exterior case) for covering the exterior cabinet 17 with the optical box 4 and the like stored therein.

  Next, a reflection type liquid crystal display element (reflection type) composed of the lamp 1, the illumination optical system α, the color separation / synthesis optical system β, and the projection lens optical system 70 (see FIG. 2) in the projection lens barrel 3 described above. An optical configuration of a projection type image display apparatus equipped with an image forming element such as a liquid crystal panel will be described with reference to FIG.

  In FIG. 2, 51 is an arc tube that emits white light with a continuous spectrum, and 52 is a reflector that condenses light from the arc tube 51 in a predetermined direction, and the arc tube 51 and the reflector 52 form the lamp 1. 53a is a first fly-eye lens in which rectangular lenses are arranged in a matrix, 53b is a second fly-eye lens comprising a lens array corresponding to each lens of the first fly-eye lens, and 54 is a non-polarized light. It is a polarization conversion element that aligns with predetermined polarized light. 55 is an ultraviolet cut filter, 56 is a reflection mirror for converting the optical axis by 90 degrees, and 57 is a condenser lens. The illumination optical system α is configured as described above.

    58 is a dichroic mirror that reflects light in the blue (B) and red (R) wavelength regions and transmits light in the green (G) wavelength region, and 59 has a polarizing element 59b attached to the transparent substrate 59a. An incident-side polarizing plate for G, which transmits only S-polarized light. Reference numeral 60 denotes a first polarization beam splitter that transmits P-polarized light and reflects S-polarized light, and has a polarization separation surface.

  Reference numerals 61R, 61G, and 61B are a reflective liquid crystal display element for red, a reflective liquid crystal display element for green, and a reflective liquid crystal display element for blue that reflect incident light and modulate the image, respectively. 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. Reference numeral 63 denotes a G output-side polarizing plate in which a polarizing element 63b is bonded to a transparent substrate 63a, and transmits only P-polarized light. Reference numeral 64 denotes an incident-side polarizing plate for RB in which a polarizing element 64b is bonded to a transparent substrate 64a, and transmits only S-polarized light. Reference numeral 65 denotes a first color-selective retardation plate that converts the polarization direction of B light by 90 degrees and does not convert the polarization direction of R light. Reference numeral 66 denotes a second polarization beam splitter that transmits P-polarized light and reflects S-polarized light, and has a polarization separation surface. Reference numeral 67 denotes a second 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. A first color selective phase difference plate 65 and a second color selective phase difference plate 67 are attached to the second polarization beam splitter 66. Reference numeral 68 denotes an output side polarizing plate for RB in which a polarizing element 68b is bonded to a transparent substrate 68a, and transmits only S-polarized light. Reference numeral 69 denotes a third polarization beam splitter (color synthesis means) that transmits P-polarized light and reflects S-polarized light, and has a polarization separation surface.

  The dichroic mirror 58 to the third polarizing beam splitter 69 constitute a color separation / synthesis optical system.

  Reference numeral 70 denotes a projection lens optical system, and the illumination optical system, color separation / synthesis optical system, and projection lens optical system constitute an image display optical system.

  Next, the optical action will be described.

  The light emitted from the arc tube 51 is collected in a predetermined direction by the reflector 52. The reflector 52 has a paraboloid shape, 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 51 is not an ideal point light source but has a finite size, the condensed light flux includes many light components that are not parallel to the symmetry axis of the paraboloid. Yes. These condensed light beams are incident on the first fly-eye lens 53a. The first fly-eye lens 53a is configured by combining lenses having a positive refractive power having a rectangular outer shape in a matrix, and the incident light beam is divided into a plurality of light beams corresponding to the respective lenses and condensed. Then, a plurality of light source images are formed in the vicinity of the polarization conversion element 54 in a matrix through the second fly-eye lens 53b.

  The polarization conversion element 54 includes a polarization separation surface, a reflection surface, and a half-wave plate, and a plurality of light beams collected in a matrix form are incident on and transmitted through the polarization separation surface corresponding to the column. The light is divided into component light and reflected S-polarized component light. The reflected light of the S polarization component is reflected by the reflecting surface and is emitted in the same direction as the P polarization component. On the other hand, the transmitted P-polarized light component is transmitted through the half-wave plate, converted into the same polarized light component as the S-polarized light component, and emitted as light having the same polarization direction. The plurality of light beams that have undergone polarization conversion exit from the polarization conversion element 54, pass through the ultraviolet cut filter 55, and are reflected by the reflection mirror 56 by 90 degrees to reach the condenser lens 57 as divergent light beams.

  Due to the lens refractive index relationship of the condenser lens 57, a rectangular uniform illumination area is formed by overlapping a plurality of rectangular images. Reflective liquid crystal display elements 61R, 61G, and 61B, which will be described later, are arranged in this illumination area. Next, the light converted to S-polarized light by the polarization conversion element 54 enters the dichroic mirror 58. The dichroic mirror 58 reflects B (430 to 495 nm) and R (590 to 650 nm) light and transmits G (505 to 580 nm) light.

  Next, the G optical path will be described.

  The G light transmitted through the dichroic mirror 58 enters the incident side polarizing plate 59. The G light remains S-polarized light after being decomposed by the dichroic mirror 58. The G light exits from the incident-side polarizing plate 59, then enters the first polarizing beam splitter 60 as S-polarized light, and is reflected by the polarization separation surface, to the G reflective liquid crystal display element 61G. It reaches. In the reflective liquid crystal display element 61G for G, the G light is image-modulated and reflected. Of the image-modulated G reflected light, the S-polarized light component is reflected again by 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 P-polarized component of the image-modulated G reflected light passes through the polarization separation surface of the first polarization beam splitter 60 and travels to the third polarization beam splitter 69 as projection light. At this time, in a state where all the polarization components are converted to S-polarized light (a state in which black is displayed), 1/4 provided between the first polarizing beam splitter 60 and the G-use reflective liquid crystal display element 61G. By adjusting the slow axis of the wave plate 62G in a predetermined direction, the influence of the disturbance of the polarization state generated in the first polarizing beam splitter 60 and the reflective liquid crystal display element 61G for G can be suppressed to a low level. The G light emitted from the first polarization beam splitter 60 is analyzed by the emission-side polarizing plate 63 that transmits only the P-polarized light. As a result, the invalid component generated by passing through the first polarizing beam splitter 60 and the reflective liquid crystal display element 61G for G is cut. Then, the G light enters the third polarization beam splitter 69 as P-polarized light, passes through the polarization separation surface of the third polarization beam splitter 69, and reaches the projection lens 70.

  On the other hand, the R and B lights reflected by the dichroic mirror 58 enter the incident side polarizing plate 64. Note that the R and B light remains S-polarized light after being decomposed by the dichroic mirror 58. The R and B lights are emitted from the incident-side polarizing plate 64 and then incident on the first color-selective retardation plate 65. The first color-selective retardation plate 65 has an effect of rotating the polarization direction of only B light by 90 degrees, so that the B light becomes P-polarized light and the R light becomes S-polarized light. The light enters the beam splitter 66. 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 reflective liquid crystal display element 61R. The B light incident on the second polarization beam splitter 66 as P-polarized light passes through the polarization separation surface of the second polarization beam splitter 66 and reaches the B-use reflective liquid crystal display element 61B.

  The R light incident on the R reflective liquid crystal display element 61R is image-modulated and reflected. The S-polarized light component of the image-modulated R reflected 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 R light reflected by the image modulation passes through the polarization separation surface of the second polarization beam splitter 66 and travels to the second color selective phase plate 67 as projection light.

  The B light incident on the B reflective liquid crystal display element 61B is image-modulated and reflected. The P-polarized component of the image-modulated B reflected light is again transmitted through 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 S-polarized light component of the image-modulated B reflected light is reflected by the polarization separation surface of the second polarization beam splitter 66 and travels toward the second color selective phase plate 67 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 reflective liquid crystal display elements 61R and 61B for R and B, G As in the case of, the black display of R and B can be adjusted.

  The R light of the R and B projection lights that are combined into one light flux and emitted from the second polarization beam splitter 66 is rotated by 90 degrees in the polarization direction by the second color selective phase plate 67, and the light S It becomes a polarization component, is further analyzed by the exit-side polarizing plate 68, and enters the third polarization beam splitter 69. The B light passes through the second color-selective phase plate 67 as it is as S-polarized light, is further analyzed by the exit-side polarizing plate 68, and enters the third polarizing beam splitter 69. The R- and B-projection lights are analyzed by the exit-side polarizing plate 68, so that the R and B reflective liquid crystal display elements 61R and 61B, and the quarter-wave plate are reflected by the second polarizing beam splitter 66. Ineffective components generated by passing through 62R and 62B are cut light.

  The R and B projection light incident on the third polarization beam splitter 69 reflects the polarization separation surface of the third polarization beam splitter 69 and is combined with the G light reflected on the polarization separation surface described above. To the projection lens 70.

  The combined R, G, B projection light is enlarged and projected onto a projection surface such as a screen by the projection lens 70.

  Since the optical path described above is for the case where the reflective liquid crystal display element displays white, the optical path for the case where the reflective liquid crystal display element displays black will be described below.

  First, the G optical path will be described.

  The S-polarized light of the G light that has passed through the dichroic mirror 58 enters the incident-side polarizing plate 59, and then enters the first polarizing beam splitter 60 and is reflected by the polarization separation surface. It reaches the element 61G. However, since the reflective liquid crystal display element 61G displays black, the G light is reflected without being image-modulated. Accordingly, even after being reflected by the reflective liquid crystal display element 61G, the G light remains as S-polarized light, so that it is reflected again by the polarization separation surface of the first polarization beam splitter 60 and transmitted through the incident-side polarizing plate 59. Then, it is returned to the light source side and removed from the projection light.

  Next, the R and B optical paths will be described.

  S-polarized light of R and B light reflected from the dichroic mirror 58 enters the incident-side polarizing plate 64. The R and B lights are emitted from the incident-side polarizing plate 64 and then incident on the first color-selective retardation plate 65. The first color-selective retardation plate 65 has an effect of rotating the polarization direction of only B light by 90 degrees, so that the B light becomes P-polarized light and the R light becomes S-polarized light. The light enters the beam splitter 66. 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 reflective liquid crystal display element 61R. The B light incident on the second polarization beam splitter 66 as P-polarized light passes through the polarization separation surface of the second polarization beam splitter 66 and reaches the B-use reflective liquid crystal display element 61B. Here, since the R reflective liquid crystal display element 61R displays black, the R light incident on the R reflective liquid crystal display element 61R is reflected without being image-modulated. Therefore, even after being reflected by the reflective liquid crystal display element 61R for R, the R light remains as S-polarized light, and is reflected again by the polarization separation surface of the first polarizing beam splitter 60, and is incident on the incident side polarizing plate. 64 is returned to the light source side and is removed from the projection light, so that a black display is obtained. On the other hand, the B light incident on the B reflective liquid crystal display element 61B is reflected without being image-modulated because the B reflective liquid crystal display element 61B displays black. Therefore, even after being reflected by the reflective liquid crystal display element 61B for B, the B light remains as P-polarized light, so that it again passes through the polarization separation surface of the first polarization beam splitter 60, and the first color. The light is converted to S-polarized light by the selective phase difference plate 65, passes through the incident-side polarizing plate 64, returns to the light source side, and is removed from the projection light.

  The above is the optical configuration in the projection type image display apparatus using the reflective liquid crystal display element (reflective liquid crystal panel).

  Next, the mechanical configuration of the lamp cooling unit in the projection type image display apparatus will be described in detail with reference to FIGS.

  3 and 4, first, the lamp 1 and the projection lens barrel 3 are close to each other due to the optical configuration described above, while the lamp cooling fan 11 is located with respect to the lamp 1. The lamp 1 is cooled by sending a blowing air, and the gap between the lamp 1 and the projection lens barrel 3 is arranged at a predetermined interval. 2 is housed in the projection lens barrel 3, and at least a part of the projection lens system 70 has a recent downsizing, higher magnification, and cost reduction. A plastic lens is mounted so as to correspond to the above. Similarly, a lens barrel that holds the projection lens system 70 is made of a plastic material (for example, a polycarbonate material) for some of the lens holding barrels.

  Next, the flow of wind by the lamp cooling fan 11 will be described.

  As can be seen from FIG. 3 and FIG. 4, a cooling method using the blowing force of the lamp cooling fan 11 is adopted as a method for cooling the lamp 1. The rotation of the lamp cooling fan 11 creates a wind flow by the suction force with respect to the projection lens barrel 3 to cool the projection lens barrel 3 itself, while the wind of the lamp cooling fan 11 continues in the direction of the lamp 1. It will hit the reflector 52. A part of this wind passes through the notch 52 a provided in the reflector 52 and hits the arc tube 51 to cool the arc tube 51. The purpose of cooling the arc tube 51 is to keep the temperature of the arc tube 51 constant and maintain proper lamp brightness. The wind passes through another notch 52 b provided in the reflector 52, and is configured to discharge the wind outside the projection type image display device via the exhaust louver 14. On the other hand, most of the wind hitting the reflector 52 flows around the reflector 52 to reach the exhaust louver 14 while cooling the reflector 52 itself, and then discharges the wind outside the projection type image display device. Has been.

  In such a configuration, the lamp cooling fan 11 is cooled by blowing air directly on the surface of the reflector 52 of the lamp 1 on the projection lens barrel 3 side, so that the lamp cooling fan 11 is compared with the surface of the reflector 52 on the exhaust louver 14 side. Therefore, since the radiation heat from the lamp on the surface of the reflector 52 on the projection lens barrel 3 side is reduced (the surface of the reflector 52 on the projection lens barrel 3 side is directly applied as cooling air, the temperature distribution of the reflector 52 The surface of the reflector 52 on the side of the projection lens barrel 3 has a lower temperature), and the projection lens barrel 3 is configured so that the influence of the lamp radiant heat is suppressed as much as possible. For example, as described above, even when the glass material of the projection lens barrel 3 and the projection lens system 70 (see FIG. 2) is made of a plastic material, aberration fluctuation and imaging performance deterioration due to temperature change. Because it is less susceptible to changes in lens spacing due to expansion and contraction of the lens barrel, decentering between lenses, optical performance deterioration due to tilting, etc., it has become possible to obtain a high-quality projection image display device .

  On the other hand, the direction in which the wind of the lamp cooling fan 11 flows from the projection lens barrel 3 to the lamp 1 is configured to be substantially straight, so that the wind is smoothly received without receiving wind resistance as much as possible. Therefore, efficient cooling is possible, and even if the fan voltage of the lamp cooling fan 11 is lowered, sufficient cooling capacity can be obtained, and a high-quality projection type that is excellent in noise reduction. It was also possible to obtain an image display device.

  Next, the distance X (see FIGS. 3 and 4) between the projection lens barrel 3 and the lamp cooling fan 11 will be described with reference to FIGS.

  FIG. 5 is a graph showing the relationship of the noise of the lamp cooling fan 11 with respect to the distance X between the projection lens barrel 3 and the suction port of the lamp cooling fan 11. Generally, in order to reduce the noise (wind noise) of the fan, it is necessary to set the obstacle (projection lens barrel 3 in the case of Example 1) as close as possible to the fan suction port as much as possible. As a matter of course, when the distance X was determined, the noise level did not change when the distance was 15 mm or more, and the noise level increased a little when the distance was 5 mm to 15 mm. In other words, as a projection type image display device, a projection type image display device which can achieve low noise by separating the suction port of the lamp cooling fan 11 from the projection lens barrel 3 by at least 5 mm or more becomes possible. .

  FIG. 6 is a graph showing the relationship of the wind speed at the position of the projection lens barrel 3 by the lamp cooling fan 11 with respect to the distance X between the projection lens barrel 3 and the suction port of the lamp cooling fan 11. Generally, cooling of the member to be cooled (projection lens barrel 3 in the case of Example 1) requires a wind speed of 1 m / s or more, and the circulation of the cooling air becomes incomplete at a wind speed of 1 m / s or less. Although the possibility that the cooling efficiency is deteriorated increases, the distance X between the projection lens barrel 3 where the wind speed of 1 m / s is generated and the suction port of the lamp cooling fan 11 is obtained. The wind speed was 1 m / s or less.

  Therefore, as can be seen in FIGS. 5 and 6, when the lamp cooling fan 11 is arranged such that the distance X between the projection lens barrel 3 and the suction port of the lamp cooling fan 11 is set to 5 mm to 40 mm, the lamp cooling fan 111. It has been found that a high-efficiency, high-quality projection image display device can be obtained without causing a decrease in cooling efficiency and noise.

(Reference example)
Next, a lamp cooling fan arrangement for another optical configuration of the projection type image display apparatus will be described with reference to FIG.

  In FIG. 7, the optical configuration of the projection type image display device will be described first.

  An arc tube 81 emits white light with a continuous spectrum, and a reflector 82 condenses the light from the arc tube 81 in a predetermined direction. The arc tube 81 and the reflector 82 form a lamp A. 83a is a first fly-eye lens in which rectangular lenses are arranged in a matrix, 83b is a second fly-eye lens comprising a lens array corresponding to each lens of the first fly-eye lens, and 84 is an optical axis of 90. A reflection mirror 85 for converting the degree of light, and 85 is a polarization conversion element for aligning non-polarized light with predetermined polarized light. 86 is an ultraviolet cut filter, and 87 is a condenser lens. The illumination optical system α is configured as described above.

  Reference numeral 88 denotes a dichroic mirror that reflects light in the blue (B) and red (R) wavelength regions and transmits light in the green (G) wavelength region, and 89 has a polarizing element 89b attached to the transparent substrate 89a. An incident-side polarizing plate for G, which transmits only S-polarized light. A first polarization beam splitter 90 transmits P-polarized light and reflects S-polarized light, and has a polarization separation surface.

  Reference numerals 91R, 91G, and 91B denote a reflective liquid crystal display element for red, a reflective liquid crystal display element for green, and a reflective liquid crystal display element for blue that reflect incident light and modulate the image, respectively. 92R, 92G, and 92B are respectively a quarter wavelength plate for red, a quarter wavelength plate for green, and a quarter wavelength plate for blue. Reference numeral 93 denotes an exit side polarizing plate for G in which a polarizing element 93b is bonded to a transparent substrate 93a, and transmits only P-polarized light. Reference numeral 94 denotes an incident-side polarizing plate for RB in which a polarizing element 94b is bonded to a transparent substrate 94a, and transmits only S-polarized light. Reference numeral 95 denotes a first color selective phase difference plate that converts the polarization direction of the B light by 90 degrees and does not convert the polarization direction of the R light. Reference numeral 96 denotes a second polarization beam splitter that transmits P-polarized light and reflects S-polarized light, and has a polarization separation surface. Reference numeral 97 denotes a second 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. Note that a first color selective phase difference plate 95 and a second color selective phase difference plate 97 are attached to the second polarizing beam splitter 96. Reference numeral 98 denotes an output side polarizing plate for RB in which a polarizing element 98b is bonded to a transparent substrate 98a, and transmits only S-polarized light. Reference numeral 99 denotes a third polarization beam splitter (color combining means) that transmits P-polarized light and reflects S-polarized light, and has a polarization separation surface.

  The above dichroic mirror 88 and the third polarizing beam splitter 99 constitute a color separation / synthesis optical system.

  Reference numeral 100 denotes a projection lens optical system, and the illumination optical system, color separation / synthesis optical system, and projection lens optical system constitute an image display optical system.

  Next, the optical action will be described.

  The light emitted from the arc tube 81 is collected in a predetermined direction by the reflector 82. The reflector 82 has a paraboloid shape, 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 81 is not an ideal point light source but has a finite size, the condensed light flux includes a lot of light components that are not parallel to the symmetry axis of the paraboloid. Yes. These condensed light beams are incident on the first fly-eye lens 83a. The first fly-eye lens 83a is configured by combining lenses having a positive refractive power having a rectangular outer shape in a matrix, and the incident light beam is divided into a plurality of light beams corresponding to each lens and condensed. Then, the light is reflected by 90 degrees on the reflection mirror 84, passes through the second fly-eye lens 83b, and forms a plurality of light source images in the vicinity of the polarization conversion element 85 in a matrix.

  The polarization conversion element 85 includes a polarization separation surface, a reflection surface, and a half-wave plate, and a plurality of light beams collected in a matrix form are incident on and transmitted through a polarization separation surface corresponding to the column. The light is divided into component light and reflected S-polarized component light. The reflected light of the S polarization component is reflected by the reflecting surface and is emitted in the same direction as the P polarization component. On the other hand, the transmitted P-polarized light component is transmitted through the half-wave plate, converted into the same polarized light component as the S-polarized light component, and emitted as light having the same polarization direction. The plurality of light beams that have undergone polarization conversion exit from the polarization conversion element 85, pass through the ultraviolet cut filter 86, and reach the condenser lens 87 as divergent light beams.

  Due to the lens refractive index relationship of the condenser lens 87, a rectangular uniform illumination area is formed by overlapping the rectangular images of the plurality of light beams. Reflective liquid crystal display elements 91R, 91G, and 91B, which will be described later, are arranged in this illumination area. Next, the light converted to S-polarized light by the polarization conversion element 85 enters the dichroic mirror 88. The dichroic mirror 88 reflects light of B (430 to 495 nm) and R (590 to 650 nm) and transmits light of G (505 to 580 nm).

  Next, the G optical path will be described.

  The G light transmitted through the dichroic mirror 88 enters the incident side polarizing plate 89. The G light remains S-polarized light after being decomposed by the dichroic mirror 88. The G light exits from the incident-side polarizing plate 89, then enters the first polarizing beam splitter 90 as S-polarized light, and is reflected by the polarization separation surface, to the G reflective liquid crystal display element 91G. It reaches. In the reflective liquid crystal display element 91G for G, the G light is image-modulated and reflected. Of the image-modulated G reflected light, the S-polarized light component is reflected again by the polarization separation surface of the first polarization beam splitter 90, returned to the light source side, and removed from the projection light. On the other hand, the P-polarized component of the image-modulated G reflected light passes through the polarization separation surface of the first polarization beam splitter 60 and travels to the third polarization beam splitter 99 as projection light. At this time, in a state where all the polarization components are converted to S-polarized light (in a state where black is displayed), ¼ provided between the first polarizing beam splitter 90 and the reflective liquid crystal display element 91G for G. By adjusting the slow axis of the wave plate 92G in a predetermined direction, it is possible to suppress the influence of disturbance of the polarization state generated in the first polarizing beam splitter 90 and the G-use reflective liquid crystal display element 91G. The G light emitted from the first polarization beam splitter 90 is analyzed by the exit-side polarizing plate 93 that transmits only the P-polarized light. As a result, the invalid component generated by passing through the first polarizing beam splitter 90 and the reflective liquid crystal display element 91G for G is cut. Then, the G light is incident on the third polarization beam splitter 99 as P-polarized light, passes through the polarization separation surface of the third polarization beam splitter 99, and reaches the projection lens 100.

  On the other hand, the R and B lights reflected by the dichroic mirror 88 enter the incident side polarizing plate 94. The R and B lights remain S-polarized light even after being decomposed by the dichroic mirror 88. The R and B lights are emitted from the incident-side polarizing plate 94 and then incident on the first color-selective retardation plate 95. The first color-selective phase difference plate 95 has an action of rotating the polarization direction by 90 degrees only for the B light, so that the B light is P-polarized and the R light is S-polarized. The light enters the beam splitter 96. The R light incident on the second polarization beam splitter 96 as S-polarized light is reflected by the polarization separation surface of the second polarization beam splitter 96 and reaches the R reflective liquid crystal display element 91R. The B light incident on the second polarization beam splitter 96 as P-polarized light passes through the polarization separation surface of the second polarization beam splitter 96 and reaches the B reflective liquid crystal display element 91B.

  The R light incident on the R reflective liquid crystal display element 91R is image-modulated and reflected. The S-polarized light component of the image-modulated R reflected light is reflected again by the polarization separation surface of the second polarization beam splitter 96, 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 reflected light is transmitted through the polarization separation surface of the second polarization beam splitter 96 and travels toward the second color-selective phase plate 97 as projection light.

  The B light incident on the B reflective liquid crystal display element 91B is image-modulated and reflected. The P-polarized component of the image-modulated B reflected light is again transmitted through the polarization separation surface of the second polarization beam splitter 96, returned to the light source side, and removed from the projection light. On the other hand, the S-polarized component of the image-modulated B reflected light is reflected by the polarization separation surface of the second polarizing beam splitter 96 and travels toward the second color selective phase plate 97 as projection light.

  At this time, by adjusting the slow axes of the quarter-wave plates 92R and 92B provided between the second polarizing beam splitter 96 and the reflective liquid crystal display elements 91R and 91B for R and B, G As in the case of, the black display of R and B can be adjusted.

  Thus, the R light of the R and B projection lights emitted from the second polarization beam splitter 96, which is combined into one light beam, is rotated 90 degrees in polarization direction by the second color selective phase plate 97, and S It becomes a polarization component, is further analyzed by the exit-side polarizing plate 98, and enters the third polarization beam splitter 99. The B light passes through the second color-selective phase plate 97 as it is as S-polarized light, is further analyzed by the exit-side polarizing plate 98, and enters the third polarizing beam splitter 99. The R- and B-projection lights are analyzed by the exit-side polarizing plate 98, so that the R and B reflection type liquid crystal display elements 91R and 91B, ¼ wavelength plates are reflected from the second polarization beam splitter 96. Ineffective components generated by passing through 92R and 92B become light that is cut.

  Then, the R and B projection light incident on the third polarization beam splitter 99 reflects the polarization separation surface of the third polarization beam splitter 99 and is combined with the G light reflected on the polarization separation surface described above. To the projection lens 100.

  The combined R, G, and B projection light is enlarged and projected onto a projection surface such as a screen by the projection lens 100.

  Since the optical path described above is for the case where the reflective liquid crystal display element displays white, the optical path for the case where the reflective liquid crystal display element displays black will be described below.

  First, the G optical path will be described.

  The S-polarized light of the G light that has passed through the dichroic mirror 88 enters the incident-side polarizing plate 89, and then enters the first polarizing beam splitter 90 and is reflected by the polarization separation surface, and is a reflective liquid crystal display for G. It reaches the element 91G. However, since the reflective liquid crystal display element 91G displays black, the G light is reflected without being image-modulated. Accordingly, since the G light remains as S-polarized light even after being reflected by the reflective liquid crystal display element 91G, it is reflected again by the polarization separation surface of the first polarization beam splitter 90 and transmitted through the incident-side polarizing plate 89. Then, it is returned to the light source side and removed from the projection light.

  Next, the R and B optical paths will be described.

  S-polarized light of R and B light reflected from the dichroic mirror 88 is incident on the incident-side polarizing plate 94. The R and B lights are emitted from the incident-side polarizing plate 94 and then incident on the first color-selective retardation plate 95. The first color-selective phase difference plate 95 has an action of rotating the polarization direction by 90 degrees only for the B light, so that the B light is P-polarized and the R light is S-polarized. The light enters the beam splitter 96. The R light incident on the second polarization beam splitter 96 as S-polarized light is reflected by the polarization separation surface of the second polarization beam splitter 96 and reaches the R reflective liquid crystal display element 91R. Further, the B light incident on the second polarization beam splitter 96 as P-polarized light passes through the polarization separation surface of the second polarization beam splitter 96 and reaches the B reflective liquid crystal display element 91B. Here, since the R reflective liquid crystal display element 91R displays black, the R light incident on the R reflective liquid crystal display element 91R is reflected without being image-modulated. Accordingly, since the R light remains as S-polarized light after being reflected by the R reflective liquid crystal display element 91R, it is reflected again by the polarization separation surface of the first polarization beam splitter 90, and is incident on the incident side polarizing plate. Since the light passes through 94 and is returned to the light source side and is removed from the projection light, black is displayed. On the other hand, the B light incident on the B reflective liquid crystal display element 91B is reflected without being image-modulated because the B reflective liquid crystal display element 91B displays black. Accordingly, even after being reflected by the reflective liquid crystal display element 91B for B, the B light remains as P-polarized light, and thus again passes through the polarization separation surface of the first polarization beam splitter 90, and the first color. The light is converted to S-polarized light by the selective phase difference plate 95, passes through the incident-side polarizing plate 94, returns to the light source side, and is removed from the projection light.

  The above is the optical configuration in the projection type image display apparatus using the reflective liquid crystal display element (reflective liquid crystal panel).

  Next, the mechanical configuration of the lamp cooling unit will be described with reference to FIG.

  In FIG. 7, first, the lamp A, the reflective liquid crystal display element 91R for the optical means 91R, and the second polarizing beam splitter 96 are close to each other due to the optical configuration described above. On the other hand, the lamp cooling fan 111 is configured to cool the lamp A by sending blowing air to the lamp A. The lamp A and R reflective liquid crystal display element 91R, and the lamp A The second polarizing beam splitter 96 is disposed with a predetermined interval in the gap.

  Next, the flow of wind by the lamp cooling fan 111 will be described.

  As can be seen from FIG. 7, since a cooling method using the blowing force of the lamp cooling fan 111 is adopted as a method for cooling the lamp A, the wind flow of the lamp cooling fan 111 is the lamp cooling. The rotation of the fan 111 creates a wind flow by the suction force for the reflective liquid crystal display element 91R for R and the second polarizing beam splitter 96, and the reflective liquid crystal display element 91R for R and the second liquid crystal display element 91R. While the polarization beam splitter 96 is cooled, the wind of the lamp cooling fan 111 flows in the direction of the lamp A as it is and hits the reflector 82 to cool the reflector 82 itself.

  In such a configuration, the lamp cooling fan 111 is cooled by blowing air directly on the surface of the reflector 82 of the lamp A on the R reflective liquid crystal display element 91R side. Since the radiant heat from the lamp on the surface of the liquid crystal display element 91R side is reduced (the surface of the reflector 82 on the reflective liquid crystal display element 91R side for R is directly applied as cooling air, the temperature distribution of the reflector 52 The surface of the reflector 52 on the R reflective liquid crystal display element 91R side has a low temperature), the R reflective liquid crystal display element 91R, and the second polarizing beam splitter 96 are affected by the radiant heat of the lamp as much as possible. It is configured to be suppressed.

As for the influence of the lamp radiant heat, in the case of a polarizing beam splitter, when the polarizing beam splitter itself generates heat, a temperature distribution is generated in the prism, particularly when the volume of the polarizing beam splitter itself is large. When this temperature distribution occurs, internal stress is generated in the optical glass material itself, and as a result, birefringence occurs due to the linear elasticity of incident light being elliptically polarized due to photoelasticity, that is, the relationship of reflection and transmission. Collapses (unnecessary polarization components are generated, and reflection and transmission are not performed reliably). As a result, leakage light reaches the projection surface, resulting in a decrease in contrast and a high-quality projection-type image display device. However, if the lamp cooling fan 111 is arranged as in the reference example , the influence of the lamp radiant heat on the polarizing beam splitter 96 can be suppressed as much as possible.

In the case of a reflective liquid crystal display element, the reflective liquid crystal display element itself generates heat when it is affected by the radiant heat of the lamp. However, there is a problem that color unevenness occurs and a high-quality projection image display device cannot be obtained. However, if the lamp cooling fan 111 is arranged as in the reference example , the reflective liquid crystal display element It has become possible to suppress the influence of the radiant heat on the 91R as much as possible.

  On the other hand, the wind-reflecting liquid crystal display element 91R for the wind of the lamp cooling fan 111 and the second polarizing beam splitter 96 are configured so that the direction of flow from the second polarizing beam splitter 96 to the lamp A is substantially linear. The wind can be smoothly discharged out of the projection type image display apparatus without being received, and efficient cooling becomes possible, and sufficient cooling capacity can be obtained even if the fan voltage of the lamp cooling fan 111 is lowered. In addition, it has become possible to obtain a high-quality projection image display device that is excellent in noise reduction.

Note that the projection display device including the light source unit described in the first embodiment and the reference example and an image signal supply device (for example, a personal computer, a video camera, a digital camera, or the like) that supplies an image signal thereto can be combined. For example, it is possible to provide an image projection system suitable for a conference, a briefing session, a screening session, or the like. At this time, communication between the reflective liquid crystal display device and the image signal input device may be performed via a communication cable or using a wireless LAN system.

The perspective view of the projection display apparatus of Example 1 of this invention. The figure of the projection display apparatus carrying the reflective liquid crystal display element of this invention The top view of the lamp cooling mechanism structure of Example 1 of this invention Sectional drawing of the lamp cooling mechanism structure of Example 1 of this invention The graph showing the relationship between the lamp cooling fan of Example 1 of this invention, and the noise of the distance of a projection lens barrel. The graph showing the relationship with the wind speed of the distance of the lamp cooling fan of Example 1 of this invention, and a projection lens barrel. Arrangement of Projection Display Device and Lamp Cooling Fan Mounted with Reflective Liquid Crystal Display Element of Reference Example of the Present Invention

DESCRIPTION OF SYMBOLS 1 Lamp 2 Lamp holder 3 Projection lens barrel 4 Optical box 4a Lamp case member 5 Optical box lid 6 Power supply 7 Ballast power supply 8 Circuit board 9 Optical cooling fan 10 Fan duct 11 Lamp cooling fan 12 Fan holding stand 13 Electric cooling fan 14 Exhaust Louver 15 Ventilation duct 16 Heat shield member 16a Main body portion 16b Extension portion 17 Exterior cabinet 18 Exterior cabinet lid 51 Light emitting tube 52 Reflector 53a First fly-eye lens 53b Second fly-eye lens 54 Polarization conversion element 55 Ultraviolet cut filter 56 Reflective mirror 57 Condenser lens 58 Dichroic mirror 59 Incident side polarizing plate 60 First polarizing beam splitter 61R, 61G, 61B Reflective liquid crystal display element 62R, 62G, 62B 1/4 wave Long plate 63 Outgoing side polarizing plate 64 Incident side polarizing plate 65 First color selective phase difference plate 66 Second polarizing beam splitter 67 Second color selective phase difference plate 68 Outgoing side polarizing plate 69 Third polarizing beam Splitter 70 Projection lens optical system

Claims (6)

A projection display device that projects light onto a projection surface by a projection optical system using light from a light source,
A cooling fan that is arranged between the projection optical system and the light source and sends cooling air from the projection optical system to the light source;
An exterior case that covers the projection optical system, the cooling fan, and the light source;
The outer case has an exhaust port for discharging the cooling air,
The projection optical system, the cooling fan, the light source, and the exhaust port are arranged such that cooling air flows along a straight line from the projection optical system through the cooling fan and the light source to the exhaust port.
The light source includes an arc tube and a reflector having first and second cutout portions provided on the cooling fan side and the exhaust port side,
The cooling fan sends cooling air to the reflector and also sends cooling air to the arc tube via the first notch, and the cooling air that has cooled the arc tube is from the second notch. A projection display device, which flows to the exhaust port. The projection display device according to claim 1, wherein the cooling fan is disposed at a distance of 5 mm to 40 mm from the projection optical system. The projection display device according to claim 1, further comprising an exhaust louver between the light source and the exhaust port. A light source that emits light in a first direction;
An illumination optical system that emits light from the light source in a second direction perpendicular to the first direction;
A color separation / synthesis optical system that includes an image forming element and emits light from the illumination optical system in a third direction opposite to the first direction;
A projection optical system for projecting light from the color separation / synthesis optical system in the third direction;
A cooling fan that is arranged between the projection optical system and the light source and sends cooling air from the projection optical system to the light source;
An exterior case that covers the projection optical system, the color separation / synthesis optical system, the illumination optical system, the cooling fan, and the light source;
The outer case has an exhaust port for discharging the cooling air,
The projection optical system, the cooling fan, the light source, and the exhaust air are arranged such that cooling air flows along a straight line from the projection optical system to the exhaust port via the cooling fan and the light source,
The light source includes an arc tube and a reflector having first and second cutout portions provided on the cooling fan side and the exhaust port side,
The cooling fan sends cooling air to the reflector and also sends cooling air to the arc tube via the first notch, and the cooling air that has cooled the arc tube is from the second notch. A projection display device, wherein the projection display device flows to the exhaust port. The illumination optical system includes a reflection mirror, a first fly-eye lens, and a second fly-eye lens,
The projection display device according to claim 4, wherein the reflection mirror is disposed closer to the color separation / synthesis optical system than the first fly-eye lens and the second fly-eye lens. A projection display device according to any one of claims 1 to 5;
An image projection system comprising: an image signal supply device that supplies an image signal to the projection display device.

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