Abstract:
A filter device which may include first and second filter elements allowing air to pass therethrough, and first and second filter holding members holding the first and second filter elements such that they are linearly connected side by side. The holding members being connected to be foldable in the position where the filter elements are connected.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority from Japanese Patent Application No. JP 2010-041999 filed in the Japanese Patent Office on Feb. 26, 2010, the entire content of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a filter device and a projector apparatus having such a filter device. More particularly, the invention relates to a filter device required for taking in external air and to a technique used in a projector apparatus having such a filter device. 
     2. Description of the Related Art 
     An electronic apparatus according to the related art such as projector apparatus for projecting images have a cooling mechanism for suppressing heat generated at internal processing sections as a result of operations of the apparatus by taking external air into the apparatus to cool the same. 
     When an apparatus takes in cooling air, the external air is sent to a filter to remove particles of dust in the same, and the air is thereafter taken into the apparatus. Particles of dust are removed from air with a filter as thus described to prevent the entry of particles of dust which can adversely affect the apparatus. 
     A filter of the type described above must receive maintenance such as cleaning or replacement each time the apparatus employing the filter is operated to a certain degree, and the filter is therefore constructed such that it can be inserted and removed in and from the apparatus. 
     Mechanisms for inserting and removing a filter in and from a projector apparatus according to the related art include relatively simple mechanisms formed by an external air intake port and a filter covering the same, a frame-like element formed by the external air intake port and the filter holding the same serving as an inserting/removing mechanism. 
     There are alternative mechanisms in which a frame member holding a filter is slid into an apparatus from a side of the body of the apparatus and in which the filter is disposed in the middle of a duct provided in the apparatus for taking external air into the apparatus. When such a mechanism is used in a projector apparatus, there is no need for disposing a filter at an external air intake port which is visible on the exterior of the apparatus. Therefore, the mechanism allows the filter to be inserted and removed in and from the apparatus while allowing the apparatus designed with relatively good appearance. 
     JP-A-10-186513 (Patent Document 1) discloses an exemplary projector apparatus in which a filter 241 is disposed to be attachable to an air intake port as shown in FIG. 3 accompanying the document. 
     SUMMARY OF THE INVENTION 
     In order to improve the efficiency of cooling utilizing external air in the above-described type of apparatus, it is required to increase the size of an eternal air intake port and to increase the surface area of a filter. However, when an excessively large filter is used, the problem of degradation of operability arises when the filter is inserted and removed in and from an apparatus. The use of a large filter is preferable in that the filter is less likely to undergo clogging and the cycle of cleaning of the filter can be extended. However, measures must be taken to dispose a large filter properly. 
     For example, in the case of the above-described mechanism in which a frame member holding a filter is slid into an apparatus from a side of the body of the apparatus to house the filter inside the apparatus, if the filter has a great size in the longitudinal direction thereof, the filter can hit a wall and the like when it is pulled out from the apparatus. Projector apparatus are mostly fixed to a predetermined location in a room, e.g., the ceiling of the room when they are used. In the case of a projector apparatus fixed along a wall, a filter pulled out from the apparatus for the purpose of maintenance may interfere with the wall, and the replacement of the filter may be disabled in some cases. Therefore, the apparatus must be installed at such a distance from the wall that filter replacement can be carried out. However, when a filter of a greater size is used, the distance at which the apparatus must be spaced from the wall to allow filter replacement increases accordingly, which has been problematic in that there are increased limitations on the installation of the apparatus. 
     Under the circumstance, it is desirable to reduce limitations placed on the replacement of a filter for taking external air into an apparatus. 
     According to an embodiment of the invention, there is provided a filter device to be used in an apparatus having an intake port for taking external air into the body of the apparatus. 
     The filter device includes first and second filter elements allowing air taken in through the intake port to pass therethrough and first and second filter holding members holding the first and second filter elements such that they are linearly connected side by side, the holding members being connected to be foldable in the position where the filter elements are connected. 
     A projector constituting the apparatus body has a filter insertion hole through which the first and second filter holding members are slid in the direction of the linear alignment between them. Thus, the filter holding members can be contained in the apparatus body. 
     In such a configuration, when the first and second filter holding members are inserted through the filter insertion hole, one of the filter holding member can be inserted with the other filter holding member folded. It is therefore possible to insert and remove the filters in and from the apparatus for the replace and cleaning of the filters if a space having a length equal to or greater than the length of one filter holding member is available beside the apparatus body. 
     According to the embodiment of the invention, one of the filter holding member can be inserted with the other filter holding member folded. The filters can be replaced or cleaned if a space having a length equal to or greater than the length of one filter holding member is available beside the apparatus body. Therefore, the space required for the installation of an apparatus body can be smaller than that in the related art, and limitations placed on a space where an apparatus body is to be installed are relaxed compared to limitations placed according to the related art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a projector apparatus according to an embodiment of the invention showing an exemplary general configuration thereof; 
         FIG. 2  is a perspective view of the projector apparatus according to the embodiment of the invention showing a filter member partially inserted therein; 
         FIG. 3  is a side view of the projector apparatus according to the embodiment of the invention in the state shown in  FIG. 2 ; 
         FIG. 4  is a perspective view of the projector apparatus according to the embodiment of the invention showing an exemplary internal configuration thereof; 
         FIG. 5  is a perspective view of the projector apparatus according to the embodiment of the invention showing the exemplary internal configuration thereof; 
         FIG. 6  is a perspective view of a filter member according to the embodiment of the invention showing an exemplary configuration thereof; and 
         FIG. 7  is a partially exploded perspective view of the filter member shown in  FIG. 6 . 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Embodiments of the invention will now be described. The following items will be described in the order listed. 
     1. Overall Configuration of Projector Apparatus ( FIGS. 1 to 3 ) 
     2. Configuration of Filter ( FIGS. 6 and 7 ) 
     3. Flow of Air taken through Air Intake Port ( FIGS. 4 and 5 ) 
     4. Modifications 
     [1. Overall Configuration of Projector Apparatus] 
       FIG. 1  is an illustration showing an overall configuration of a projector apparatus according to an embodiment of the invention. 
     The present embodiment is a projector apparatus which displays an image as follows. An optical block provided in the apparatus irradiates a display panel with light from a light source. Image light (projection light) of an image to be displayed formed by transmitting or reflecting the light from the light source at the display panel is projected on a screen through a projection lens to display the image. 
     As shown in  FIG. 1 , a projection lens  11  is mounted on a front end of the body of a projector apparatus  10 , the body being formed by a box-like housing. Projection light exits the projection lens  11 . 
       FIG. 1  shows one side face and a rear end of the projector apparatus  10 . Two air intake ports  12  and  13  are disposed on the side face such that they extend side by side in the horizontal direction. Air taken through the air intake ports  12  and  13  blows on an optical block in the projector apparatus  10  as a cooling air flow. The intake air is passed through filters  31  and  32  mounted to a filter member  20  as shown in  FIG. 1  (the filter  31  is not shown in  FIG. 1 ), although details of the configuration for passing the intake air will be described later. The filter member  20  is shown outside the apparatus in  FIG. 1 . 
     The filter member  20  of the present embodiment has an elongate shape, and the member is formed by connecting two filter holding portions, i.e., a first filter holding portion and a second filter holding portion  22  into a straight shape at a connecting portion  26 . One of the filter holding portions can be folded toward the other filter holding portion at the connecting portion  26 . A specific configuration of the filter member  26  will be described later. 
     A cover  14  is mounted to a rear end  15  of the body of the projector apparatus  10 . The cover  14  is shown apart from the apparatus body in  FIG. 1 . As shown in  FIG. 1 , a filter insertion hole  16  is exposed by removing the cover  14 . The filter member  20  formed by connecting two filter holding portions into a straight shape is linearly inserted into the filter insertion hole  16  from one end  20   a  thereof. When the filter member  20  has been completely inserted into the filter insertion hole  16 , another end  20   b  of the filter member  20  is exposed at the filter insertion hole  16 . A grip portion  28  is provided at the end  20   b , and a maintenance worker can remove the filter member  20  by pulling out the filter member  20  with the grip portion  28  held by his or her fingers. 
       FIG. 2  shows a state in which the filter member  20  has been inserted into the filter insertion hole  16  halfway (the second filter holding portion  22  has been inserted halfway). 
     As shown in  FIG. 2 , when only the second filter holding portion  22  is inserted with the first filter holding portion  21  kept outside the filter insertion hole  16 , the first filter holding portion  21  can be folded upward about the connecting portion  16  serving as a fulcrum. 
       FIG. 3  is a side view of the apparatus in the same state as shown in  FIG. 2 , and  FIG. 3  shows a state in which the first filter holding portion  21  is folded and lifted upward. 
     Therefore, as shown in  FIG. 3  the filter member  20  can be replaced with new one when a distance L from the rear end  15  of the projector apparatus  10  to a wall  90  exceeds half of the length of the filter member  20  (or the length of each of the filter holding portions  21  and  22 ) even in a small amount. 
     [2. Configuration of Filter] 
     An exemplary configuration of the filter member  20  of the present embodiment will now be described with reference to  FIGS. 6 and 7 . 
       FIG. 6  is a general perspective view of the filter member  20 , and  FIG. 7  shows an exploded view of the second filter holding portion  22  with the first filter holding portion  21  shown in an assembled state. The first filter holding portion  21  and the second filter holding portion  22  have the same configuration for holding the filter, the configuration being shown in the exploded view of the second filter holding portion  22  in  FIG. 7 . 
     As shown in  FIG. 6 , the filter member  20  is formed by connecting the first filter holding portion  21  and the second filter holding portion  22  at a connecting portion  26  such that holding portions are integrated to extend straightly, each of the holding portions being formed from a resin. The connecting portion  26  is a bendable and rotatable connecting portion, as described above. Specifically, as shown in  FIG. 6 , the connecting portion  26  is formed by connecting an end  21   a  of the top surface of the first filter holding portion  21  with an end  22   a  of the top surface of the second filter holding portion  22  using a resin film having a thickness smaller than the thickness of the regions of the holding portions surrounding the same. Since the connecting portion  26  has a small thickness as thus described, the first filter holding portion  21  and the second filter holding portion  22  can be folded toward each other. 
     For example, as indicated by the arrow X in  FIG. 6 , the filter member  20  can be folded such that one end  20   b  of the filter member  20  is put in contact with another end  20   a  of the same. 
     When the filter member is folded such that the top surface of the first filter holding portion  21  is put into contact with the top surface of the second filter holding portion  22 , an engaging part  29   a  provided at the end  20   a  engages an engaging part  29   b  provided at the other end  20   b  to keep the member in the folded state. That is, the engaging parts  29   a  and  29   b  serves as anchoring mechanism parts for holding the first filter holding portion  21  and the second filter holding portion  22  in a lapped state. 
     When a filter member  20  is transported to be mounted to an apparatus or to be used as a replacement for maintenance, the member can be transported in such a folded state. The elongate filter member  20  can be transported with its length shortened as thus described. 
     When the first filter holding portion  21  and the second filter holding portion  22  are arranged in the straight state as shown in  FIG. 6 , an end of a protrusion  21   b  of the first filter holding portion  21  and an end of a protrusion  22   b  of the second filter holding portion  22  abut on each other in a position lower than the connecting portion  26 . The abutment between the ends of the protrusions  21   b  and  22   b  regulates the first filter holding portion  21  and the second filter holding portion  22  to prevent the holding portions from being folded in the opposite directions. Specifically, although the first filter holding portion  21  can be folded or lifted upward as indicated by the arrow X, the first filter holding portion  21  can not be folded downward. 
     Ribs  27  are provided on both lateral surfaces of each of the first filter holding portion  21  and the second filter holding portion  22  of the filter member  20 .  FIGS. 6 and 7  show the ribs  27  provided on one side of the filter holding portions with the ribs on the other side omitted. 
     When the filter member  20  is inserted into a filter insertion hole  16  as shown in  FIG. 1 , the ribs  27  fit in grooves  16   a  provided on the duct section  70  as will be described later to allow the filter member  20  to be slid linearly. 
     The mechanism of the first filter holding portion  21  and the second filter holding portion  22  for holding filters  31  and  32  will now be described with reference to  FIG. 7 . As described above, the first filter holding portion  21  and the second filter holding portion  22  hold the filters  31  and  32  using the same configuration. The disposition of a filter in the second filter holding portion  22  will now be described with reference to  FIG. 7 , and the description completely applies to the first filter holding portion  21 . 
     As shown in  FIG. 7 , a holding frame  23  is provided at the bottom of a frame made of resin which constitutes the second filter holding portion  22 , and the filter  31  is supported by the holding frame  23  at a bottom surface thereof. 
     The filter  31 , which is constituted by a sponge-like resin sheet or nonwoven fabric, is placed on the holding frame  23 . 
     The filter  31  has holes  31   a  provided in four positions near edges thereof, and protrusions  24  provided on the holding frame  23  in four inward positions thereof (only two locations are shown) are inserted into the holes  31   a  of the filter  31  to secure the filter  31  in place. 
     A frame-like spacer  40  constituted by a resin member is disposed on the filter  31 , and the filter  32  is disposed on the spacer  40 . The filter  32  is also constituted by a sponge-like resin sheet or nonwoven fabric, but the filter  31  is formed from a material having finer pores through which are is allowed to pass when compared to the filter  32 . 
     The filter  32  also has holes  32   a  provided at four corners thereof, and protrusions  41  provided at four corners of the spacer  40  are inserted into the holes  32   a  of the filter  32  to secure the filter  32  in place. 
     Further, a presser member  50  is placed on the filter  32  to press the top surface of the filter  32 . The presser member  50  has three protrusions  51  provided in three positions on each side thereof, and the protrusions  51  are engaged with respective anchoring parts  25  provided in six locations on side faces of the body of the second filter holding portion  22  to secure the presser member  50 , whereby the filters  31  and  32  are secured in place. 
     Two filters  31  and  32  are disposed in each of the first filter holding portion  21  and the second filter holding portion  22  such that the filters are spaced from each other at a predetermined interval. Thus, particles of dust included in air taken from the outside are removed by the four filters in total. 
     [3. The flow of Air from Intake Ports] 
     The flow of air taken in through the air intake ports  12  and  13  shown in  FIG. 1  will now be described with reference to  FIGS. 4 and 5 . 
       FIG. 4  is an illustration showing the external shape of the optical block  60  in the projector apparatus  10  and showing a duct section  70  disposed beside the optical block  60 . The external shape of the projector apparatus  10  (the shape of the housing) is represented by an imaginary line (two-dot chain line). A filter member  20  is horizontally disposed in the duct section  70  shown in  FIG. 4 .  FIG. 5  shows the configuration of the apparatus with the duct section  70  omitted (to show the filter member  20 ). 
     As shown in  FIG. 4 , the duct section  70  has a plurality of openings  73  provided in series on a side of the same associated with the position where the air intake ports  12  and  13  show in  FIG. 1  are disposed, and the filter member  20  is disposed at the bottom of the duct section  70 . 
     Further, two Scirocco fans  71  and  72  are disposed under the filter member  20  to cause air filtered through the filter member  20  to blow on the bottom of the optical block  60  disposed adjacent to the duct section. The two Scirocco fans  71  and  72  blow external air on a part of the optical block  60  where a display panel section  62  is disposed, i.e., a heat-generating part of the optical block  60  to cool the part. In the present embodiment, three display panels are disposed to form the display panel section  62 , and the two Scirocco fans and  72  supply air to the three display panels in cooperation with each other. Air is also supplied from the Scirocco fans  71  and  72  to a light source section  61 , which is another heat-generating part of the optical block  60 , to cool the section. 
     As will be apparent from the disposition of the filter member  20  illustrated in  FIG. 5 , the two Scirocco fans  71  and  72  are disposed directly under the filter member  20 . Therefore, external air taken in through the openings  73  of the duct section  70  (or the air intake ports  12  and  13 ) reaches the Scirocco fans  71  and  72  after passing through the four filters  31  and  32  of the filter member  20 . Thus, the air is supplied to the Scirocco fans  71  and  72  with particles of dust removed from the same. 
     As described above, in the projector apparatus  10  of the present embodiment, filters having a relatively large surface area are disposed as filter for cleaning cooling air, whereby a filter member  20  extending substantially the entire length of the side face of the apparatus is formed. Operations of mounting and removing the filter member  20  in and from the apparatus can be carried out in a small space. 
     Specifically, since the filter member  20  can be folded in the middle thereof as shown in  FIGS. 2 and 3 , the filter member can be replaced with new one even when a wall  90  exists near the rear end of the apparatus if a distance L that is substantially equivalent to one half of the length of the filter member  20  is left between the apparatus and the wall. 
     The use of large filters allows cleaning and maintenance operations to be carried out at longer intervals, and the space required around the projector apparatus  10  to perform such operations can be small. Thus, the embodiment is advantageous in that limitations placed on a space for installing the main body of the projector apparatus can be relaxed when compared to the related art. 
     The first filter holding portion  21  and the second filter holding portion  22  of the filter member  20  are made foldable toward each other by a simple resin feature having a small thickness connecting the holding portions  21  and  22 . Therefore, the connecting portion can be formed at the same time when the holding portions  21  and  22  are molded from a resin. This is advantageous in that the connecting portion for allowing the filter member to be folded can be formed simply at a low cost. 
     When the filter member  20  is transported to be mounted to an apparatus or to be used as a replacement for maintenance, the member can be folded to halve the length thereof as indicated by the arrow X in  FIG. 6 . Thus, the elongate filter member  20  can be transported with its length shortened as thus described, and the transportation of the filter member  20  can be carried out with improved operability. 
     Further, since the filter member  20  is constructed so as to be easily locked in the folded state by the engaging portions  29   a  and  29   b , particles of dust deposited on the filters  31  and  32  can be confined in the filter member. It is therefore possible to prevent particles of dust from scattering when the filter member  20  is removed from the projector apparatus  10  for transportation. 
     The two filters  31  and  32  held by the holding portions  21  and  22  of the foldable filter member  20  are disposed at an interval from each other, and the material of the filters  31  and  32  are different in coarseness. Large particles of dust are removed when eternal air first passes through the filter  32 , and smaller particles of dust are thereafter removed by the finer filter  31 . Thus, the embodiment is advantageous in that the air filters are capable of cleaning air with very high efficiency. In addition, since the filter member  20  including the two filters  31  and  32  having a relatively great surface area can be folded compactly as thus described, the filter member can be efficiently operated. 
     [4. Modifications] 
     While the above-described embodiment is an application of the invention to a filter for cleaning cooling air for a projector apparatus which projects images, the invention may be applied to other types of electronic apparatus which must take external air into themselves. 
       FIG. 1  and other figures merely show an exemplary position of the insertion hole at which the filter member is inserted into the body of an apparatus such as a projector apparatus and exemplary positions of air intake ports, 
     The configuration in which each of the filter holding portions  21  and  22  holds two filters  31  and  32  is also merely an example. Each filter holding portion may alternatively be configured such that only one filter is disposed therein. 
     Although the filter member  20  of the present embodiment is configured to be folded halfway at one folding position, two or more folding positions may alternatively be provided. 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.