JP5405853B2 - Projection display device - Google Patents

Description

  The present invention relates to a projection-type image display apparatus that includes an image display element and an illumination optical system, modulates a light beam obtained by the illumination optical system by the image display element, and projects an image on a screen. The present invention relates to a dust removal filter provided in an air intake port for cooling the illumination optical system and the image display element.

  For example, projection video display devices such as liquid crystal projector devices and reflective video display projector devices irradiate and modulate a light beam emitted from a light source onto a liquid crystal panel or a reflective liquid crystal panel, which is an image display element, by an illumination optical system. Since the image obtained in this way is enlarged and projected by the projection lens, a high-luminance light source is required. Furthermore, since the so-called optical components constituting the above-described image display element and illumination optical system are small, the surface power density of the incident light beam is increased. For this reason, for example, when the video display element is a liquid crystal panel, light is absorbed into the liquid crystal panel, the polarizing plate, and the optical component, and heat is generated. Furthermore, it is necessary to take out the heat generated by the light source outside the apparatus.

  For this reason, conventionally, for example, as described in Patent Document 1 below, a fan is rotated by a motor to suck outside air into the apparatus, and the heat generated by the optical components and the heat of the light source described above are transmitted to the outside of the apparatus. It was released. At this time, when air outside the apparatus is sucked and blown into the air, dust outside the apparatus may enter the apparatus, and a configuration in which a mechanical or electrostatic dust removing filter is usually used is adopted. It was.

  Furthermore, the following Patent Document 2 discloses a dust collecting air blowing device that prevents dust from entering the device due to air intake by a fan and at the same time does not cause resistance to airflow, and a projection video display device including the dust collecting air blowing device. The described configuration is proposed.

Japanese Patent Laid-Open No. 2001-2222065 JP-A-2005-95828

  However, in order to improve the collection efficiency of the dust removal filter described in Patent Document 1, the width of the opening (hole) of the filter is about half of the pixel size (7 to 13 μm) of the liquid crystal panel. However, there is a problem that if the width of the filter hole is reduced, the resistance (pressure loss) is increased with respect to the air flow of the filter, so that the heat radiation efficiency is lowered.

  Furthermore, in the dust collection air blower described in the said patent document 2, the air blower of the structure which reduced the pressure loss is proposed by providing an electrical dust collection means instead of a dust removal filter. In the air blower provided with the electric dust collecting means, the dust ionized by one electrode is attracted and adsorbed by the Coulomb force at the other mesh electrode, but the electrode is used to improve the collection rate. The interval and shape are optimized using the applied voltage as a parameter. However, it is extremely difficult to collect nearly 100% of dusts having different sizes and components. Furthermore, in the conventional technique disclosed in Patent Document 1 described above, in order to increase the dust collection rate, it is necessary to increase the basis weight of the dust removal filter (to make the filter hole finer). In the case of a filter having a small dust holding amount, there are problems such as causing clogging immediately.

  On the other hand, in the dust collecting fan described in Patent Document 2, dust that has entered the inside of the apparatus through the blowing device provided with the electric dust collecting means is ionized by the action of the electric dust collecting device described above, and the image Because it adheres to the display elements and optical components in an activated state, the brightness of the projected image obtained by the projection display device is reduced, or spots and color spots are generated on the image, which is a major problem in performance. It became clear as a result of various experiments conducted by the inventors.

  Therefore, the present invention has been achieved in view of the above-described conventional technology, and prevents dust from entering the inside of the apparatus due to the intake air from the outside of the apparatus by the fan, and increases the basis weight of the dust removal filter (filter Even if the holes are miniaturized), the required filter cleaning interval can be lengthened, so that the maintenance period can be extended, and further, no dust adheres to the image display element and optical parts. Another object of the present invention is to provide a projection display apparatus capable of maintaining good performance for a long time.

  In order to achieve the above object, according to the present invention, a light beam emitted from a light source is incident on an image display element by an illumination optical system, and an image obtained by modulating the light beam by the image display element is displayed by a projection lens. A projection-type image display apparatus for enlarging projection, wherein an air intake is formed in a part of the casing of the apparatus. Inside the air intake, a dust removal filter and an external device are provided. A blower that sucks air into the apparatus through the dust removal filter, cools a part of the members constituting the illumination optical system and the video display element by the air sucked by the blower, and A projection image display device provided with a vibration applying unit that applies vibration to the dust removing filter is provided for the dust removing filters having a plurality of types of basis weight.

  According to the present invention, in the projection display apparatus, since the dust removing filter is vibrated by the vibration applying unit during the projection of the image, the cooling device is used for cooling compared with the case where the dust removing filter is not vibrated. To provide a projection type image display device that can maintain good performance for a long time without dust adhering to the inside of a set when sucked by a blower (fan) and without adhering to the image display element and optical parts. Is possible. Also, the dust attached to the dust removal filter can be shaken off from the dust removal filter by vibration different from the above, thereby suppressing clogging of the dust removal filter and maintaining the dust removal filter. It is possible to provide a projection-type image display device that has a significantly longer period than the conventional one and is excellent in usability.

1 is an overall perspective view showing an external appearance of a projection display apparatus according to an embodiment of the present invention. It is a perspective view which shows the dust removal filter structure in the projection type video display apparatus of the said invention. It is sectional drawing which shows the internal structure of the dust removal filter which becomes a 1st Example of this invention. It is sectional drawing which shows the internal structure of the dust removal filter which becomes a 2nd Example of this invention. It is sectional drawing which shows the internal structure of the dust removal filter which becomes the 3rd Example of this invention. It is sectional drawing which shows the internal structure of the dust removal filter which becomes the 4th Example of this invention. It is sectional drawing which shows the internal structure of the dust removal filter which becomes the 5th Example of this invention. It is sectional drawing which shows the internal structure of the dust removal filter which becomes the 6th Example of this invention. FIG. 4 is a cross-sectional view showing the internal configuration of the dust removal filter according to the first embodiment of the present invention, similar to FIG. 3. FIG. 5 is a cross-sectional view showing the internal configuration of the dust removal filter according to the second embodiment of the present invention, similar to FIG. 4. It is a figure explaining the principle which the electrostatic dust removal filter of this invention collects dust. It is a figure which shows an example of the performance of the electrostatic nonwoven fabric filter which comprises a dust removal filter. It is sectional drawing which shows the internal structure of the dust removal filter made as an experiment in this invention. It is a figure which shows the data which show the actual measurement result of the floating dust investigated in this invention. It is a figure which shows the data which show the actual measurement result of the floating dust investigated in this invention. It is a figure which shows the data which show the actual measurement result of the floating dust investigated in this invention. It is a figure explaining the arrangement | positioning and effect | action of an illumination optical system inside the projection type video display apparatus of this invention. It is a figure which shows the structure of the illumination optical system in the inside of a projection type video display apparatus when a cooling fan is placed horizontally with respect to the apparatus. It is a perspective view which shows an example of arrangement | positioning of the flow of the cooling air and dust removal filter in the projection type video display apparatus of this invention.

  Hereinafter, the best mode of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, the element which has a common function is attached | subjected and shown with the same code | symbol, and it abbreviate | omits the description about what was once demonstrated after that.

  FIG. 1 attached herewith is a perspective view showing an appearance of a projection display apparatus according to an embodiment of the present invention. In the figure, an illumination optical system (not shown here) for efficiently irradiating the image display element with light is provided inside the housing 10 of the projection display apparatus. In order to cool the image display element together with a part of the members constituting the optical system, a cooling air intake port 12 for sucking outside air is formed in a part of the housing 10.

  The cooling air intake port 12 is provided with a positioning (not shown) for defining the mounting position in the depth direction of the dust removal filter together with a fan not shown here, thereby removing dust. After insertion of the filter, the mesh-shaped cover 13 is integrated with a part of the apparatus, and is held and fixed. On the other hand, the exhaust from the housing 10 is provided with an exhaust port on the back side (not shown) of the lamp take-out portion 11 so that the air that has cooled the lamp is exhausted to the outside of the housing 10. FIG. 2 is a perspective view showing an embodiment of the mechanical (or electrostatic) dust removing filter of the present invention. In this embodiment, the foamed urethane 2 and the dust are absorbed electrically or mechanically ( This is a so-called composite filter 5-1, which is configured by combining a charged non-woven filter 3-3. An example of the mechanical (or electrostatic) dust removing filter as an embodiment of the present invention shown in FIGS. 3 to 11 is obtained by cutting the dust removing filter shown in the perspective view in FIG. 2 from the AA ′ direction. FIG.

FIG. 3 is a principle diagram (AA ′ cross section in FIG. 2) for easily explaining the principle of the dust removing filter according to the first embodiment of the present invention. The left side of the drawing shows the outside of the projection display apparatus housing, and the right side shows the inside of the housing. The dust removal filters 3 and 4 are filters using an electrostatic nonwoven fabric, and have an action of adsorbing dust electrically or mechanically. The fineness of the hole (opening) of this filter is represented by the basis weight (g / m ² ), and the larger the value, the higher the ability to collect dust. As an example of this electrostatic non-woven filter, for example, for an electret spunbond nonwoven fabric manufactured by Toyobo, with a basis weight, pressure loss and dust collection efficiency with different particle sizes (0.3μ and 8μ) are improved. These are collectively shown in FIG.

  In the embodiment shown in FIGS. 3 and 9, for example, the EFA-24NH shown in FIG. The shape is adjusted to a pleated shape as shown, and at the same time, it is fixed in a frame indicated by reference numeral 3-1. The frame 3-1 is attached to the vibration propagation unit 3-2 having high rigidity, and the electrostatic non-woven filter is vibrated through the vibration propagation unit by the vibration applying unit indicated by reference numeral 3-4. This vibration may be constant at a predetermined frequency “f0”, but if it is varied in accordance with the speed of the cooling air taken into the housing 10, dust can be collected more efficiently.

  More specifically, when the electrostatic non-woven filter is vibrated by the vibration propagating unit 3-2 during the operation of the apparatus (that is, during projection), the amount of dust that can be supplemented is larger than when the vibration is not vibrated. Was confirmed. Therefore, according to the present invention, based on the confirmation result, the performance of removing dust entering the inside of the projection image display device during projection is improved as compared with the conventional case.

  When the electrostatic non-woven filter is vibrated by the vibration propagation unit 3-2, since the apparatus is projecting, the projection projected by projecting the projection lens and optical system components is performed. Care must be taken so that the image is not affected. At this time, the electrostatic non-woven filter 3 is shaped like a pleat so that the surface area is increased, and the dust holding capacity can be increased. For the electrostatic non-woven filter 4 in the subsequent stage, EFA-36NH having a larger basis weight than that of the electrostatic non-woven filter in the previous stage is used, and, as in the previous stage, as shown by reference numeral 4-3, pleats are used. The shape is adjusted to a shape and fixed to the frame indicated by reference numeral 4-1. As described above, in the first embodiment of the present invention, the dust removal filter 1 (prefilter), the mechanical dust removal filter 2 made of urethane foam, the mechanical (or electrostatic) dust removal filter 3, The filter is composed of a mechanical (or electrostatic) dust removing filter 4, that is, a four-stage filter, which blocks dust entering the housing. Further, the non-woven filter 3 is vibrated during the projection of the apparatus, thereby improving the dust blocking efficiency.

  FIG. 9 shows an embodiment having the same configuration as that of FIG. 3, and the first embodiment of the present invention will be described with reference to both drawings. As shown in FIGS. 3 and 9, the mechanical dust removal filter 1 (prefilter) provided in the apparatus main body has a relatively large size (for example, 500 μm) of the dust a floating in the air. Above) Block dust. Next, the middle size (for example, ˜20 μm) dust is blocked by the mechanical dust removing filter 2 made of foamed urethane. Further, finer (for example, 20 to 10 μm) dust is blocked by the mechanical (or electrostatic) dust removing filter 3 (configured by filters indicated by reference numerals 3-1 to 3-4). Further, dust having a relatively small size (for example, 10 μm or less) is blocked by a mechanical (or electrostatic) dust removing filter 4 (configured by filters indicated by reference numerals 4-1 to 4-3).

  On the other hand, in the projection display apparatus according to the present invention, the vibration applying unit 3-4 provided in the above-described nonwoven filter 3 is vibrated during use or when the projection of the image is finished. However, the vibration applied at this time is set to a frequency lower than the predetermined frequency “f0” described above, and the purpose is to shake off dust adsorbed on the dust removal filter by the vibration. It is possible to extend the filter clogging time.

  According to the projection display apparatus according to the embodiment of the present invention including the dust removing filter 5-2 having the above-described configuration, clean air after efficiently collecting dust contained in the outside air is taken in, For example, it is possible to cool a part of the members constituting the illumination optical system and the image display element by blowing with a centrifugal blower. In addition, the dust removal filter described above is configured separately from the apparatus and can be removed, so that the customer can perform maintenance by himself such as removing it and cleaning it as necessary. By doing so, the usability can be further improved.

  FIG. 4 is a principle diagram (A-A ′ cross section in FIG. 2) for explaining the second embodiment of the present invention. Similar to FIG. 3 above, the left side of the drawing shows the outside of the projection display apparatus housing, and the right side shows the inside of the housing. These dust removing filters 3 and 4 are filters using an electrostatic nonwoven fabric, and have an action of adsorbing dust electrically and mechanically. The difference from the first embodiment of the present invention shown in FIGS. 3 and 9 is that the dust removal filter 3 and the dust removal filter 4 are integrated.

  In the second embodiment, as shown in FIG. 4 and FIG. 10, for example, the EFA-25NH shown in FIG. 12 is adopted for the preceding-stage electrostatic nonwoven filter 3 close to the cooling air intake 12. Then, as shown by reference numeral 3-3, the shape is adjusted to a pleat shape and fixed to the frame indicated by reference numeral 3-1. The frame 3-1 is attached to the vibration propagation unit 3-2 having high rigidity, and the electrostatic non-woven filter 3-1 is vibrated through the vibration propagation unit 3-2 by the vibration applying unit 3-4. At the same time, these are integrated, and the fixed dust removing filter 4 also vibrates in synchronization. This vibration may be constant at the predetermined frequency “f0” as in the first embodiment, but more efficiently by changing according to the speed of the cooling air taken into the housing, It becomes possible to collect dust. However, since the total weight of the vibrating filter becomes large, it is necessary to generate a large vibration energy in the vibration applying unit 3-4 as compared with the first embodiment.

  For the latter-stage electrostatic nonwoven filter 4, EFA-40NH having a larger basis weight than that of the former-stage electrostatic nonwoven filter 3 is used, and the shape thereof is arranged in a pleat shape as indicated by reference numeral 4-3. At the same time, it is fixed to the frame indicated by reference numeral 4-1. As described above, also in the second embodiment of the present invention, a dust removal filter 1 (prefilter), a mechanical dust removal filter 2 made of urethane foam, a mechanical electrostatic dust removal filter 3, a machine As a four-stage filter comprising the electrostatic dust removing filter 4 of the type, the dust that enters the housing is blocked.

  FIG. 10 shows an embodiment having the same configuration as that of FIG. 4. The second embodiment of the present invention will be described below with reference to these drawings.

  As shown in FIGS. 4 and 10, among the dust a floating in the air by the mechanical dust removing filter 1 (prefilter) provided in the apparatus main body, the dimension is relatively large (for example, 500 μm or more). ) Block dust. Next, the middle size (for example, ˜20 μm) dust is blocked by the mechanical dust removing filter 2 made of foamed urethane. Further, finer (for example, 20 to 10 μm) dust is blocked by the mechanical (or electrostatic) dust removing filter 3 (configured by filters denoted by reference numerals 3-1 to 3-4). Further, the dust having a relatively small size (for example, 10 μm or less) is blocked by the mechanical (or electrostatic) dust removing filter 4 (configured by the filters of reference numerals 4-1 to 4-3).

  On the other hand, also in the projection type image display apparatus as the second embodiment of the present invention, the electrostatic non-woven filter 3 is used in the same manner as in the first embodiment described above during use or when the image projection is finished. The provided vibration imparting unit 3-4 is vibrated. Here, since the dust removal filter 3 and the dust removal filter 4 have an integrated configuration, it goes without saying that vibration is efficiently transmitted to the dust removal filter 4. At this time, the vibration to be applied is set to a frequency lower than the predetermined frequency “f0” described above, so that the dust adhering to the dust removal filter is shaken off by the vibration, thereby extending the filter clogging time. It becomes possible.

  In the projection display apparatus according to the embodiment of the present invention provided with the dust removing filter 5-3 having the above-described configuration, clean air after the dust contained in the outside air is efficiently collected is taken into the interior. It is possible to cool a part of the members constituting the illumination optical system and the image display element by blowing with the centrifugal blower provided. In addition, the above-described dust removal filter is separated from the apparatus and can be removed, so that the customer can perform maintenance by himself, such as removing and cleaning as necessary. By doing so, the usability is further improved as in the first embodiment of the present invention.

  FIG. 5 is a principle diagram (A-A ′ cross section in FIG. 2) for explaining the third embodiment of the present invention. As in FIG. 3 above, the left side of the drawing shows the outside of the projection display apparatus housing, and the right side shows the inside of the housing. The dust removal filters 3 and 4 are filters using an electrostatic nonwoven fabric, that is, have an action of adsorbing dust electrically and mechanically. The difference from the first and second embodiments of the present invention shown in FIGS. 3 and 4 is that the vibration applying portion 4-4 is provided in the dust removal filter 4.

  In this third embodiment, for example, the EFA-24NH shown in FIG. 12 is adopted for the preceding-stage electrostatic nonwoven filter 3 close to the cooling air intake port 12, and indicated by reference numeral 3-3. As described above, by adjusting the shape into a pleated shape, the surface area is increased, the dust holding capacity is increased, and the frame is fixed to the frame indicated by reference numeral 3-1.

  The latter-stage electrostatic nonwoven filter 4 is made of EFA-36NH having a larger basis weight than the former-stage electrostatic nonwoven filter, and in the same manner as the previous stage, in a pleated shape as indicated by reference numeral 4-3. The shape is adjusted and fixed to the frame indicated by reference numeral 4-1. The frame 4-1 is attached to the vibration propagation unit 4-2 having high rigidity, and the electrostatic nonwoven filter 4 is vibrated through the vibration propagation unit 4-2 by the vibration applying unit 4-4. This vibration may be constant at a predetermined frequency “f0”. However, if the vibration is varied in accordance with the speed of the cooling air taken into the housing, dust can be collected more efficiently. .

  As described above, in the third embodiment of the present invention, the dust removing filter 1 (pre-filter), the mechanical dust removing filter 2 made of foamed urethane, and the mechanical (or electrostatic) dust removing filter 3 are used. The so-called four-stage filter composed of a mechanical (or electrostatic) dust removal filter 4 blocks dust that enters the housing.

  FIG. 6 is a principle diagram (A-A ′ cross section in FIG. 2) for explaining a fourth embodiment of the present invention. As in FIG. 4 above, the left side of the drawing shows the outside of the projection display apparatus housing, and the right side shows the inside of the housing. The dust removal filter 3 and the dust removal filter 4 are filters using an electrostatic nonwoven fabric, that is, have an action of adsorbing dust electrically and mechanically. The difference from the second embodiment shown in FIG. 4 is that the vibration applying unit 4-4 is provided in the dust removal filter 4.

  In the fourth embodiment, for example, the EFA-25NH shown in FIG. 12 is adopted for the preceding-stage electrostatic non-woven filter 3 close to the cooling air intake port 12, and reference numeral 3-3 is used. As shown in the figure, by adjusting the shape into a pleated shape, the surface area is increased and the dust holding capacity is increased, and at the same time, the frame is fixed to the frame indicated by reference numeral 3-1.

  For the electrostatic non-woven filter 4 in the subsequent stage, EFA-40NH having a larger basis weight than the electrostatic non-woven filter in the previous stage is used, and as in the previous stage, its shape is pleated as indicated by reference numeral 4-3. Are fixed to the frame indicated by reference numeral 4-1. The frame 4-1 is attached to the highly rigid vibration propagation portion 4-2, and the entire vibration type non-woven filter 4 is vibrated through the vibration propagation portion 4-2 by the vibration applying portion 4-4. The integrated electrostatic nonwoven filter 3 is also vibrated simultaneously. This vibration may be constant at a predetermined frequency “f0”. However, it is possible to collect dust more efficiently by changing it according to the speed of the cooling air taken into the housing.

  As described above, according to the fourth embodiment of the present invention, the dust removal filter 1 (pre-filter), the mechanical dust removal filter 2 made of foamed urethane, and the mechanical (or electrostatic) dust removal. The so-called four-stage filter comprising the filter 3 and the mechanical (or electrostatic) dust removal filter 4 blocks dust that enters the housing.

  Next, FIG. 7 and FIG. 8 are principle diagrams (A-A ′ cross section in FIG. 2) for explaining the fifth and sixth embodiments of the present invention. Here, as in the first to fourth embodiments, the left side of the drawing shows the outside of the projection display apparatus housing, and the right side shows the inside of the housing. The dust removal filters 3 and 4 are so-called electrostatic non-woven filters, that is, have an action of adsorbing dust electrically and mechanically. The difference from the first to fourth embodiments of the present invention shown in FIGS. 3, 4, 5 and 6 is that the mechanical dust removing filter 2 made of urethane foam, the mechanical (or static) The electric type dust removal filter 3 and the mechanical (or electrostatic type) dust removal filter 4 are integrated. Note that the configuration and operation of each filter are the same as in the description up to the fourth embodiment, and are omitted here.

  On the other hand, also in the projection type image display apparatus using the dust removal filter according to the third to sixth embodiments described above, the same as the first embodiment described above during use or when the image projection is finished. The vibration applying unit 3-4 provided in the electrostatic nonwoven filter 3 is vibrated. According to this, since the dust removal filter 3 and the dust removal filter 4 are integrated, it goes without saying that vibration is efficiently transmitted to the dust removal filter 4.

  In addition, the vibration applied at this time is lower than the predetermined frequency “f0” described above, and the dust adhering to the dust removing filter is shaken off by the vibration, so that the filter clogging time can be extended. Become.

  According to the projection display apparatus according to the embodiment of the present invention including the dust removing filter having the above-described configuration, clean air after efficiently collecting dust contained in the outside air is taken in, and the internal A centrifugal blower can cool a part of members constituting the illumination optical system and the image display element. In addition, the dust removal filter described above can be configured so that the customer can perform the maintenance by himself / herself, for example, by removing and cleaning it as necessary, as a separate unit from the apparatus and being removable. Therefore, the usability is further improved as in the first and second embodiments of the present invention.

  Next, the arrangement and operation of the illumination optical system in the projection display apparatus including the dust removal filter having the above-described configuration and including the cooling fan will be described with reference to FIGS. .

  In FIG. 17, the light beam emitted from the light source unit 101 has its ultraviolet rays cut by the UV cut filter 102 and is incident on a pair of multi-lens arrays 103a and 103b as integrators. In addition, although an ultraviolet cut is normally performed also by another optical element, since it is not the main point of this invention including an infrared cut, the detailed description is abbreviate | omitted here.

  Convex lenses (cells) are two-dimensionally arranged in the multi-lens arrays 103a and 103b, and light beams incident on the multi-lens array 103a form a light source image two-dimensionally in each cell of the multi-lens array 103b. . Each condensed light source image is converted from natural light into linearly polarized light whose vibration direction is constant by the polarization conversion element 104. This is because the video display elements 122a, 122b, and 122c, which will be described later, pass only linearly polarized light whose vibration direction is a fixed direction. Further, the light source images divided two-dimensionally by the multi-lens arrays 103a and 103b are superimposed on the video display surfaces of the video display elements 122a, 122b, and 122c by the action of the superimposing lens 105 having a superimposing action. The light is separated into three colors of red, green, and blue by a color separation optical system between the superimposing lens 105 and the image display elements 122a, 122b, and 122c.

  A light beam with a constant deflection direction that has passed through the superimposing lens 105 and whose optical path is turned back by the total reflection mirror 106a is first transmitted by the first dichroic mirror 107a. The green light beam is reflected. The blue light beam is then reflected by the total reflection mirror 106b, and further irradiated to the blue image display element 122b via the condenser lens 108b. The red and green light beams are reflected by the second dichroic mirror 107b, while the red light beam is transmitted. The green light beam is applied to the green image display element 122a through the condenser lens 108a. The red light beam is reflected by the total reflection mirrors 106c and 106d, passes through the condenser lens 108c, and is applied to the red image display element 112c. The optical path of red light is further mapped using relay lenses 109 and 110 because the optical path length is longer than that of blue or green.

  As described above, the light beams applied to the blue image display element 122b, the green image display element 122a, and the red image display element 122c are then color-synthesized by the cross prism 111, The light enters the projection lens 120.

  In the above explanation of the principle of the illumination optical system, for a polarizing plate that cuts off light beams other than the predetermined polarized light beam present in the actual illumination optical system, a retardation plate that controls the vibration direction of the polarized light beam of each color, etc. Since it is not the gist of the present invention, detailed description thereof is omitted here.

  Next, FIG. 17 is a layout diagram showing a configuration in which the cooling fan 112b (not shown here) is placed vertically with respect to the apparatus. The air that has passed through the dust collecting filter storage unit 20 formed by combining a plurality of types of mechanical and electrostatic dust removing filters together with the filter 1 is displayed on the image through the duct 113 by the cooling fan 112b (not shown here). The element and the deflecting plate (not shown here) are cooled. Further, the dust collection filter storage unit 20 is screwed or bonded and fixed inside the apparatus.

  Next, FIG. 18 is a diagram showing a configuration when the cooling fan 112a is placed horizontally with respect to the apparatus. Similarly to the embodiment shown in FIG. 17, mechanical dust attached to the apparatus main body is shown. The air that has passed through the dust collection filter storage unit 20 formed by combining a plurality of types of mechanical and electrostatic dust removal filters together with the removal filter 1 passes through the duct 113 by the cooling fan 112b (not shown here). The display element and the deflection plate (not shown here) are cooled. Further, the dust collection filter storage unit 20 is screwed or bonded and fixed inside the apparatus.

  FIG. 19 shows a projection image display apparatus according to the present invention, a dust collection filter storage unit 20 for storing a dust removal filter (not shown here), blower fans 112a and 112b (not shown here), and a duct 113. Is a specific example for showing how they are arranged with respect to the image display elements 122c, 122b, 122a and the cross prism (not shown here) which are main components of the illumination optical system. FIG. Dust contained in the air sucked from the outside of the apparatus is collected by a dust removing filter (not shown here) housed in the dust collection filter storage unit 20 and taken into the apparatus, and blower fans 112a and 112b (here, FIG. The air is blown through the duct 113 to cool the main components of the illumination optical system. Specifically, the pre-filter formed integrally with the apparatus mechanically blocks dust having a relatively large size (for example, 500 μm or more) among the dust a floating in the air.

  Next, as described in the basic principle with reference to FIG. 3, the dust removing filters 3 and 4 are constituted by a filter using an electrostatic nonwoven fabric inside the storage unit 20 and are in the air. Part of the members constituting the illumination optical system and the image display element are removed by blowing fans 112a and 112b (not shown here) by sucking the dust by electrically and mechanically adsorbing the dust. A dust removal filter having the configuration shown in FIGS. 3 and 13 was made as a prototype, a prototype built in the storage unit 20 shown in FIG. 19 was created, and the effect was verified.

  As the electrostatic nonwoven filter, for example, an electret spunbond nonwoven fabric manufactured by Toyobo is used, and the electrostatic nonwoven filter 3 in the previous stage close to the cooling air intake port 12 is shown in FIG. While adopting EFA-24NH, as shown by reference numeral 3-3, its shape is adjusted to a pleat shape and fixed to the frame 3-1. The frame 3-1 was attached to the vibration propagation unit 3-2 having high rigidity, and the electrostatic non-woven filter was vibrated through the vibration propagation unit 3-2 by the vibration applying unit 3-4. This vibration preferably has a frequency of about 1000 Hz to 5000 Hz. However, depending on the weight of the removal dust removing filter, vibration outside this frequency range is also effective. Also, the wind speed of the cooling air taken into the housing 10 changes depending on the amount of dust collected by the dust removal filter, but according to the change in the wind speed, that is, the higher the wind speed, the higher the vibration frequency, Furthermore, it becomes possible to collect dust efficiently.

  The electrostatic non-woven filter 3 was arranged in a pleated shape, so that the surface area was increased, and the dust holding capacity could be increased. The latter electrostatic non-woven filter 4 is made of EFA-36NH having a larger basis weight than that of the former electrostatic non-woven filter, and the shape thereof is pleated as shown by reference numeral 4-3 in the same manner as the previous stage. While arranging, it was set as the structure fixed to the frame shown with the code | symbol 4-1. As described above, the prototype dust removal filter includes a dust removal filter 1 (pre-filter), a mechanical dust removal filter 2 made of urethane foam, a mechanical (or electrostatic) dust removal filter 3, and a mechanical type. A so-called four-stage filter composed of (or electrostatic) dust removal filter 4 was used.

  Note that the above-described four-stage dustproof removal filter investigates the particle size of airborne dust in the environment of use, and, for example, goes to the latter stage (blower side) so that the dust with the investigated particle size distribution can be almost covered. It is preferable that the particle size of the dust to be captured is smaller.

  In the prototype, mechanically large dust removal filter 1 (pre-filter) provided in the apparatus body blocks dust having a relatively large size (for example, 500 μm or more) out of dust a floating in the air. Next, dust having a middle dimension (for example, 500 to 20 μm) is blocked by a mechanical dust removal filter 2 made of urethane foam. Further, finer (for example, 20 to 10 μm) dust is blocked by the mechanical electrostatic dust removing filter 3 (configured by the filters 3-1 to 3-4). Furthermore, the mechanical electrostatic dust removing filter 4 (configured by the filters 4-1 to 4-3) is configured to block dust having a relatively small size (for example, 10 μm or less).

  In making the above-described four-stage dustproof filter, the particle size of suspended dust in the air in different regions including the country, that is, in different usage environments (rooms and laboratories) is set. investigated. The result of this investigation is shown in FIG. As is clear from this figure, for example, in the classification (range) of the suspended dust particle size of 0.3 μm to 0.5 μm, the number of particles in the region B per liter of air is 40000 to 50000, The number of particles in region A different from this was 240000, which was about 5 times. Similarly, the number of particles in the region B per liter of air is 2000 to 3000 in the section of the suspended dust particle size of 0.5 μm to 0.7 μm, whereas in the different region A, it is about 65,000. 30 times.

  Moreover, the area was calculated | required according to the particle size of floating dust from said result, and the result is shown in attached FIG. As a result, the particle size of the floating dust in the air in the usage environment in the region A was the maximum in the section of 1.0 μm to 2.0 μm.

Furthermore, from the above results, the weight per unit volume (m ³ ) was determined for each particle size of the suspended dust, and the results are shown in FIG. As a result, the weight of the airborne dust in the environment of use in the region A has the maximum value in the section having a particle size of 1.0 μm to 2.0 μm. This was followed by values in the 3 μm to 0.7 μm section. From this result, the dust removal filter described above has a configuration having a plurality of types of dust removal filters having different basis weights.

  Furthermore, the principle by which the electrostatic dust removing filter collects dust will be described with reference to FIG. The electrostatic dust removing filter, for example, creates an electretized ultrafine fiber of submicron to several tens of nanometers by applying a high voltage to a polymer solution or polymer melt extruded from a metal thin tube, and this is used as a ground electrode. Manufactured by creating a non-woven fabric by layering on top. In order to increase the dust holding capacity, the apparent surface area can be increased by arranging the nonwoven fabric in a pleated shape.

  At this time, suspended dust b in the air tends to enter the inside of the casing from the outside (left side in FIG. 11) to the inside (right side in FIG. 11) together with the cooling air sucked by the centrifugal blower. However, in the vicinity of the valley 3-3c of the electrostatic dust removing filter formed in a pleat shape, the wind speed becomes slow due to the pressure loss, and it adheres to the eyes of fine fibers due to the mechanical force together with the electrostatic force. After that, due to clogging of the filter, the pressure loss gradually increases even in the inclined part 3-3b in the figure, and the wind speed is slowed down. To do. For this reason, in order to efficiently collect dust finer than the fibers, the filter itself may be vibrated at high speed. On the other hand, in order to shake off the dust once adsorbed from the filter, an external force (in this case, vibration) exceeding the electrostatic force or mechanical force of the filter may be simultaneously applied to the dust and the filter.

  In order to verify the above facts, the electrostatic dust removal filter prototype described above is set in the projection-type image display device, and when the device is in use and when the image projection is finished, the above-described electrostatic nonwoven fabric is used. The vibration applying unit 3-4 or 4-4 provided in the filter 3 was vibrated. As shown in Table 1 below, the vibration applied at this time is about 1000 Hz to 5000 Hz when trapped dust is captured by a filter, and on the other hand, the vibration is 300 Hz or less, which is a lower frequency than this. According to the above, it is possible to shake off the dust adsorbed on the dust removing filter by vibration. In order to more efficiently shake off the dust adsorbed on the dust removal filter by vibration, it has been confirmed that it is preferable to apply vibration having a frequency of 100 Hz or less. Further, the vibration applied to the filter preferably has an amplitude of about ± 4 μm when trapping suspended dust, and has an amplitude of about ± 100 μm when shaken off by vibration.

  In addition, as a specific means for applying vibration, for example, a vibration motor is used, and the frequency of vibration is changed by controlling the number of rotations, or a voice coil of a speaker is used, and the frequency and amplitude of vibration. It is possible to change the vibration and vibrate. As a result, the clogging time can be extended even when the dust removal filter is used in an area where there is a lot of floating dust.

  In the projection display apparatus according to the embodiment of the present invention having the dust removal filter having the above-described configuration, clean air after efficiently collecting dust contained in the outside air is used as an internal centrifugal blower. By cooling a part of the members constituting the illumination optical system and the image display element, the adhesion of dust to the image display element and optical parts is reduced compared to the conventional case, and good performance is achieved for a long time. It is possible to provide a projection display apparatus that can be maintained. Further, the above-described dust removing filter is separated from the apparatus and can be removed, so that the customer can remove and clean as necessary, and can perform maintenance by himself / herself. This further improves the usability of the device.

  As described above, according to the present invention, the image display element and the illumination optical system are provided inside the casing, and the light beam obtained by the illumination optical system is modulated by the image display element to project an image on the screen. Projection-type image display device, for example, a liquid crystal projector device or a reflection-type image display projector device, which is particularly excellent in dustproofness, improved adhesion of dust to the image display element and optical components, for a long time, It is possible to provide a projection display apparatus capable of maintaining good performance.

DESCRIPTION OF SYMBOLS 11 ... Lamp removal part, 10 ... Projection type image display apparatus, 12 ... Cooling air intake 1 ... Pre filter, 2 ... Mechanical dust removal filter, 3-1 ... Frame, 3-2 ... Vibration propagation part, 3-3 ... Mechanical (electrostatic) dust removing filter, 3-4 ... Vibration applying portion, 4-1 ... Frame, 4-2 ... Mechanical (electrostatic) dust removing filter, 5-1 ... Mechanical dust removing filter, 5 -2 ... Mechanical dust removal filter, 5-3 ... Mechanical dust removal filter, 5-4 ... Mechanical dust removal filter, 5-5 ... Mechanical dust removal filter, 5-6 ... Mechanical dust removal filter, 5 -7 ... Mechanical dust removal filter, a ... Airborne dust, b ... Airborne dust, c ... Airborne dust, 3-3a ... Mechanical (electrostatic) dust removal filter crest, 3-3b ... Mechanical (electrostatic) Dust removal filter inclined part, 3-3c ... mechanical (electrostatic) dust removal filter trough part, 112a ... Blower fan, 112b ... Blower fan, 120 ... Projection lens, 122a, 122b, 122c ... Image display element, 101 ... Light source unit, 102 ... UV cut filter, 103a, 103b ... Multi lens array, 104 ... Polarization conversion element, 105 ... Superimposing lens, 106a, 106b, 106c, 106d ... Total reflection mirror, 107a, 107b ... Dichroic mirror, 108a, 108b, 108c ... Condenser lens, 109, 110 ... Relay lens, 111 ... Cross prism, 113 ... Duct, 20 ... Mechanical (electrostatic) dust removing filter storage section, 126, 127, 128 ... Incident side polarizing plate.

Claims (8)

A projection-type image display apparatus that causes a light beam emitted from a light source to be incident on an image display element by an illumination optical system, and that an image obtained by modulating the light beam by the image display element is enlarged and projected by a projection lens. In the part of the housing of which the intake of air is formed,
The air intake port includes a dust removal filter and a blower that sucks air outside the apparatus through the dust removal filter and sucks it into the apparatus, and the illumination optical system is configured by the air sucked by the blower the part of the member and the image display device is cooled, and the dust removal filter of the multi several basis weight, provided the vibration applying unit for vibrating to the dust removal filter,
The vibration applying unit applies vibration of 1000 Hz to 5000 Hz to the dust removal filter when the image is projected by the projection display apparatus and air is sucked in by the blower.
The vibration applying unit further applies a vibration of 300 Hz or less to 50 Hz or more to the dust removal filter even after the projection of the image by the projection display apparatus is stopped. apparatus.   In the projection display apparatus according to claim 1, a part or all of the plurality of types of dust removal filters having a weight per unit area are connected to each other, and at least one of them is configured by an electrostatic dust removal filter. And the projection-type image display apparatus characterized by providing the said vibration provision part in the vicinity of the said electrostatic dust removal filter.   2. The projection display apparatus according to claim 1, wherein the plurality of types of dust removal filters having a weight per unit area are provided separately.   The projection display apparatus according to claim 1, wherein the dust removal filter disposed at a position close to the blower among the plurality of types of dust removal filters of the basis weight is the largest. The projection display apparatus according to claim 1. The projection display apparatus according to claim 1,
The vibration applying unit applies a vibration having a predetermined frequency to the dust removing filter. 6. The projection display apparatus according to claim 5, wherein the vibration applying unit is vibrated to apply vibration at a first predetermined frequency f0 to the dust removing filter so that the dust is mechanically attached to the dust removing filter. and dust removing filter a first throw shooting display apparatus you and removing at least a portion of the dust adhered by vibrating at a frequency lower than the predetermined frequency f0.   2. The projection display apparatus according to claim 1, wherein the vibration applying unit is constituted by a vibration motor.   2. The projection display apparatus according to claim 1, wherein the dust removing filter is shaped in a pleat shape.

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