Abstract:
The present invention is a projection type projector apparatus which is provided with a light source portion, a light bulb and a cooler for cooling at least the light source portion, with a silencer which takes exhaust air from the cooler once to damp exhaust sound, and a mounting portion for attachably/detachably mounting the silencer to a projection type projector.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-401171, filed Dec. 28, 2000, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates a silencer used in a projection type projector apparatus utilizing a light source and a light modulating element, and a projection type projector apparatus with the same. 
     2. Description of the Related Art 
     Currently, as a light source for a projection type projector, a discharge lamp of a short arc type such as a mercury lamp, a metal halide lamp or a xenon lamp is employed mainly. The discharge lamp emits light while it is being maintained in a high temperature of 1000° C. or so, and about 90% of the energy is not converted to light to be consumed as a heat generating source. Therefore, in view of a problem of reliability of an electrode, a discharge lamp, and a reflector itself which controls and reflects light, such a configuration must be employed that a reflector having a proper space according to power is provided to perform forced air cooling, or a vent hole is provided in a reflector to perform direct forced air cooling. 
     A conventional projection type projector apparatus will be explained using a liquid crystal projector. The liquid crystal projector is provided with a discharge lamp which is the light source, which is provided in reflector in an approximately closed state. Furthermore, a suction port and an exhaust port are provided in the projector apparatus, the fresh air is taken in via the suction port, and the fresh air is sent to a discharge lamp by a fan, and a heated air is exhausted to outside by a exhaust fan which is provided in exhaust side. As the technique describing a liquid crystal projector having such an exhausting means, there are U.S. Pat. No. 5,993,008 publication and the like. 
     Since the temperature of the discharge lamp is an extremely high temperature, when the hot air is exhausted as it is, exhaust air to be exhausted or discharged outside depends on an airflow speed but will has a high temperature of 100° C. or so. Such a high temperature is not preferable in view of safety. 
     Therefore, such a technique is employed that the speed of the hot air is increased until an arbitrary temperature can be achieved, or the hot air is mixed with a cooling air with a relatively low temperature which has been used to cool both polarizing elements, a liquid crystal panel and a polarizing plate which constitutes a light bulb, which are other parts to be cooled, so that exhaust air from the exhaust port is lowered to an arbitrary temperature. 
     In such a projection type projector apparatus, according to recent requirements for further small-sizing and higher output power, a higher power is required for the discharge lamp light source, while the apparatus set itself, namely, the reflector including the discharge lamp, both the polarizing elements and the polarizing plate constituting the light bulb, and the fan which is a cooling air suction side (exhaust side) cooler, is required for further small-sizing and weight reduction. 
     Considering the forced air cooling effected by the fan which is an ordinary cooling air suction air side (exhaust air side) cooling, when, for example, a light bulb is small-sized from 1.3 sun (which is a Japanese unit where 1 sun is equal to 1.3 inches) which is a representative value to 0.7 sun, light energy per unit area becomes 3.5 times or so correspondingly in order to maintain the same brightness. In such a case, air cooling effected by stronger air speed is required due to poor heat conductivities of almost all of the optical elements except for using expensive sapphire material for both polarizing elements or using an approach where it is difficult to secure reliability. 
     Especially, since it is assumed that a front projection type projector apparatus is used in a dark chamber environment, light leakage is not allowed from a main body thereof so that it becomes necessary to provide a complicated air passage and a narrow vent port, thereby increasing noises due to air cooling significantly. As a result, noises generated from a cooling apparatus become a problem not only in home use which is in a quiet house environment but also in ordinary business use. 
     That is, in the conventional projection type projector apparatus, there is a drawback that it is required to attain small-sizing, higher output and silence but it is much difficult to solve these conflicting demands collectively. 
     BRIEF SUMMARY OF THE INVENTION 
     In view of the above, an attachable/detachable silencer has been made or devised, and the present invention is to provide a projection type projector apparatus whose small-sizing, higher output and silence can be achieved by mounting the silencer to the apparatus only when sound or noise reduction is required without large-sizing a main body of the projection type projector apparatus, and the silencer. 
     According to an aspect of the present invention, there is provided a silencer which is mounted to a projection type projector apparatus provided with optical function including a light source portion and a light bulb, and cooling means for cooling at least the light source portion by blowing cooling air to the optical function, the silencer comprising a silencer main body which takes air flowing in the cooling means or cooling air flowing out of the cooling means into silencer main body to reduce suction sound or exhaust sound of the cooling means; and mounting means for attachably/detachably mounting the silencer main body to at least one of a cooling airflow suction side and a cooling airflow exhaust side of the cooling means of the projection type projector. 
     According to the aspect of the present invention, the silencer is made attachable/detachable so that the silencer is mounted to the projection type projector apparatus only when sound or noise reduction is required, thereby allowing small-sizing and silence of the apparatus to be achieved simultaneously. 
     And, according to an aspect of the present invention, there is provided a projection type projector apparatus which irradiates light whose light amount is controlled by a light bulb in a predetermined direction is provided with a light source provided inside the projection type projector apparatus; cooling means, provided within the projection type projector apparatus, for cooling at least the light source by blowing cooling air to the light source; a silencer main body which takes cooling air flowing from the cooling means into the silencer main body once to discharge the same, thereby damping suction sound or exhaust sound of the cooling means; and mounting means which attachably/detachably mounts the silencer main body on a cooling air exhaust side of the cooling means of the projection type projector apparatus such that the mounting angle of the silencer main body can be changed continuously so that an exhaust angle of the silencer main body can be changed continuously. 
     According to the aspect of the present invention, the projection type projector apparatus is mounted above mentioned silencer which is mounted to the projector apparatus only when sound or noise reduction is required, thereby allowing small-sizing and silence of the apparatus to be achieved, similarly. 
     Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
     FIG. 1 is a sectional view showing one example of a projection type projector apparatus with a silencer which is a first embodiment according to the present invention; 
     FIG. 2 is a sectional view showing one example of a projection type projector apparatus with a silencer which is a second embodiment according to the present invention; 
     FIG. 3 is a sectional view showing one example of a projection type projector apparatus with a silencer which is a third embodiment according to the present invention; 
     FIG. 4 is a sectional view showing one example of a projection type projector apparatus with a silencer which is a fourth embodiment according to the present invention; 
     FIG. 5 is a sectional view showing one example of a projection type projector apparatus with a silencer which is a fifth embodiment according to the present invention; 
     FIG. 6 is a sectional view showing one example of a projection type projector apparatus with a silencer which is a sixth embodiment according to the present invention; 
     FIG. 7 is a sectional view showing one example of a projection type projector apparatus with silencers which are seventh and eighth embodiments according to the present invention; and 
     FIG. 8 is a sectional view showing one example of a projection type projector apparatus with a silencer which is a ninth embodiment according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Respective embodiments of a projection type projector apparatus according to the present invention will be explained below with reference to the drawings. 
     (First Embodiment) 
     A first embodiment is for providing a silencer for a projection type projector apparatus according to the present invention as one having an attachable/detachable structure. FIG. 1 is a sectional view showing one example of a projection type projector apparatus with a silencer which is the first embodiment according to the present invention. 
     In FIG. 1, a projection type projector apparatus according to the present invention is provided with a discharge lamp  2  which serves as the maximum heat generating source, a reflector  3  for generally sealing or closing the lamp  2 , fans  7  and  8  which are air suction side coolers for sucking air from suction ports  9  and  10 , and a fan  11  for performing air exhaust from an exhaust port  12 , so that forced air cooling is conducted by room temperature air fed in by the air suction side cooling fans  7  and  8 , and hot air heated by the discharge lamp is exhausted outside from the exhaust port  12  by the exhaust side cooling fan  11 . 
     A main body  1  of the projection type projector apparatus is further provided with both polarizing elements  4  in which light from the reflector  3  is irradiated, light dividing means where light which has passes through the both polarizing elements  4  is divided by dichroic mirrors or the like to be incident on liquid crystal panels  5 , polarizing plates  6  which are arranged on input sides and output sides of the liquid crystal panels  5 , and projection means which composes lights emitted from the respective liquid crystal panels  5  to project the composed light. Also, the main body  1  further includes a power supply base plate  14 , a discharge lamp lighting circuit  15  and the like. These members must be subjected to forced cooling effected by the fans  7 ,  8  and  11  such that they are cooled down to arbitrary temperatures. 
     The present invention is further provided with an attachable/detachable silencer  16  for reducing or damping exhaust noises of the air exhaust fan  11 . The silencer  16  is structured so as to be easily attachable/detachable by using barrel holes and rivet-shaped jigs  20  (means) without necessity of, for example, screw fastening or the like. The shape of this attachable/detachable jig is not limited to the shape illustrated in the figure, but various shapes of the attachable/detachable jig can be considered according to the levels of those skilled in the art. Therefore, it should be understood that, as any attachable/detachable jig has operation and effect of the present invention, it is included in the embodiment of the present invention. 
     In such a silencer  16 , exhaust air  13  is exhausted from the exhaust port  12 , and this exhaust air includes sound or noise to be reduced or removed. Therefore, the sound or noise is absorbed while being reflected inside an interior  17  of the silencer so that the exhaust air is exhausted or discharged as exhaust air  19  from the exhaust port  18 . In order to further improve or increase sound or noise reduction effect, the interior  17  of the silencer is partitioned properly so that the sound can be reduced or damped to a required level. 
     (Second Embodiment) 
     A second embodiment includes an attachable/detachable silencer  16  like the first embodiment, but it is further structured such that a case where an exhaust port or the like is turned in a direction opposed to a direction of irradiation of a light source is specified by employing a different mounting direction of the silencer. FIG. 2 is a sectional view showing one example of a projection type projector apparatus with a silencer which is the second embodiment according to the present invention. 
     In a case that the exhaust port  18  is provided in the silencer  16  such as shown in FIG. 1, noises damped or reduced is exhausted together with exhaust air  19  collectively in a projection direction. Therefore, for example, when the projector apparatus is arranged on a center of a conference table, viewers are positioned on a rear side of the projector in many cases. Accordingly, such an arrangement is preferable since exhaust air with high noise level is not directed to the viewers. 
     In such a case as a home use of the apparatus, however, there is a case that viewers are positioned in front of the projector apparatus. In such a case, when the direction shown in FIG. 1 is employed, the exhaust air is directed to the viewers. Therefore, when viewers exist in the projection direction, comfortable environment can be provided to the viewers by positioning the exhaust port  18  in the direction opposed to the projection direction, as shown in FIG.  2 . At this time, a symmetrical structure is employed for the silencer  16 , namely the silencer  16  is structured such that the exhaust direction can be selected by changing the mounting direction of the silencer. 
     (Third Embodiment) 
     A third embodiment shows a case where silencers are provided not only on an exhaust side of the apparatus but also on a suction side thereof. FIG. 3 is a sectional view showing one example of a projection type projector apparatus with silencers which is the third embodiment according to the present invention. 
     That is, there is a case where sufficiently high level noise which will cause a drawback is generated on the suction side in addition to the exhaust air acting as the noise generating source due to forced air cooling. In this case, as shown in FIG. 3, it is preferable to provide another silencer  21  having the same structure as one provided on the exhaust side diagonally regarding the front and rear faces or both side faces of the projector. This suction side silencer  21  is attachable/detachable according to necessity by attachable/detachable jigs  22  like the exhaust side silencer  21  and it is provided with a suction port  23 . 
     (Fourth Embodiment) 
     A fourth embodiment provides a case that the mounting jig or fixture of the silencer described in the first embodiment has a rotating mechanism and the exhaust direction can be set freely. FIG. 4 is a sectional view showing one example of the projection type projector apparatus with a silencer which is the fourth embodiment according to the present invention. 
     That is, in a silencer  25  of the fourth embodiment, as shown in FIG. 4, a mounting mechanism  24  to the projection type projector apparatus  1  has a rotating mechanism, and the silencer  25  can rotate in a direction shown with, for example, arrow  27 . Therefore, it becomes possible to select the exhaust direction freely and finely, for example, as shown with a dotted line  26  so that the optimal exhaust direction can be determined according to an environment where this apparatus is used. Also, a mounting mechanism  24 - 2  may be provided on the suction side so as to perform sound (noise) reduction on the suction side. 
     (Fifth Embodiment) 
     A fifth embodiment specifies a case that, in addition to the silencer of the first embodiment, a microphone or the like is provided inside the silencer to detect exhaust noises and sounds or noises with a phase reverse to the exhaust noises is output by a noise canceling circuit and a speaker so that the exhaust noises are further reduced. FIG. 5 is a sectional view showing one example of a projection type projector apparatus with a silencer which is a fifth embodiment according to the present invention. 
     In the fifth embodiment, as shown in FIG. 5, a microphone  33  is provided within the silencer and a signal showing the exhaust noises within the silencer is transmitted to a noise canceling circuit  29  via connection terminals  31 . 
     Here, the noise canceling circuit  29  performs phase shifting or phase reversing so as to minimize the noises generated from the vent hole  18  of the silencer on the basis of information obtained via the microphone  33  provided inside the silencer  16 . By performing such a processing, it is made possible to reduce middle or lower range noise which is difficult to be damped in a cheap silencer sufficiently. (Incidentally, since high range noise has a high directionality, noise damping or reduction is easily made even by the structure shown in FIG.  5 ). 
     Incidentally, the connection terminals  31  are originally provided respectively on the silencer  16  and the projection type projector apparatus  1 . It is preferable that, when a user mounts the silencer  16  on the projection type projector apparatus  1 , the connection terminals  31  are connected to each other semi-automatically. When the silencer is mounted on the projection type projector apparatus, switching is performed from the sound outputting circuit  28  to the noise canceling circuit  29  automatically by operation of a selector circuit  30  so that sound output for noise reduction is obtained from the speaker  32 . Thereby, two noise reduction effects can be obtained from both of the silencer and the noise canceling circuit without a special burden on a user, thereby allowing more secure noise reduction processing. Also, this embodiment is further provided with a ground connection  35  and a connection jig  36 . 
     (Six Embodiment) 
     A sixth embodiment is provided on its suction side with a noise canceling function in addition to the exhaust side noise canceling function of the fifth embodiment. FIG. 6 is a sectional view showing one example of a projection type projector apparatus with a silencer which is a sixth embodiment according to the present invention. 
     The sixth embodiment is not to provide a principle of noise canceler but to provide a sound output apparatus which functions as an ordinary sound outputting apparatus at a non-mounting time of the silencer and functions as a noise canceler at a mounting time of the silencer, and an attachable/detachable silencer simultaneously. 
     A projection type projector apparatus shown in FIG. 6 is provided on its suction side with a silencer  21  having a microphone  33 - 2  and connection terminals  31 - 2 , and it is further provided with a sound outputting circuit  28 - 2  allowing a noise canceler function, a noise canceling circuit  29 - 2 , a selector circuit  30 - 2 , and a speaker  32 - 2 . 
     According to the present invention, in a case that sound outputting apparatuses are respectively provided on suction and exhaust side faces opposed to each other and a stereophonic sound outputting apparatus is provided, as shown in FIG. 6, silencers are applicable to a plurality of faces and it becomes possible to attain an original sound reduction effect of the silencer while performing noise canceling on a suction side and an exhaust side simultaneously. 
     Furthermore, as shown in FIG. 6, when it is required that sound output is left or maintained according to the circumstances, the silencer  16  or  21  is mounted on only a larger noise side of the left and right side noise generating sources or a proper face of the left and right side noise generating sources, so that such a preferable looking and listening environment can be attained that the sound output is maintained by switching the operation of the sound output apparatus positioned on a non-mounting side of the silencer to a monaural sound output operation while noise canceling operation is being performed. 
     (Seventh and Eighth Embodiments) 
     A seventh embodiment is to provide a more suitable sound environment by further providing an attachable/detachable silencer. 
     An eighth embodiment is to provide a structure where only exhaust sound (suction sound) to be detected is provided to a noise canceling circuit by filtering signals from a microphone provided in an attachable/detachable silencer. 
     FIG. 7 is a sectional view showing one example a projection type projector apparatus with silencers which are seventh and eighth embodiments according to the present invention. 
     In the seventh embodiment, the silencers  16  and  21  positioned on the exhaust side and the suction side are respectively provided with speakers  38  and  38 - 2 . Thereby, for example, when the silencer  16  is mounted on the exhaust side of the projection type projector apparatus, the original speaker  32  functions as a speaker for noise canceling, and the speaker  38  provided in the silencer  16  functions as a speaker for sound. Regarding the silencer on the exhaust side, the same specification as the above is considered. That is, in generally, it is thought that viewers (audience) are positioned on a side opposed to the exhaust port  18  of the silencer, and such a specification is preferable. 
     Namely, when the sound outputting apparatus is provided in this direction, a comfortable looking and listening environment can easily be constructed and the projection type projector apparatus becomes a mobile apparatus when both the silencers are detached from the projection type projector apparatus. In addition, when the sound outputting apparatus provided in the projection type projector apparatus is caused to function as a noise canceler in a state where the silencer is mounted to the projection type projector apparatus, effective part utilization can be achieved. 
     In the eighth embodiment, as shown in the seventh embodiment, when both the functions of the sound outputting speaker and the noise canceler are simultaneously utilized in one silencer, there may occur a drawback that the two functions interfere with each other. Therefore, sound signals from the microphones  31  and  31 - 2  are caused to match with sound output signals before they are input to the noise canceling circuits  29 ,  29 - 2 , or exhaust air is cause to pass through predetermined filter circuits  37  and  37 - 2  provided with band-pass filters corresponding to only a frequency band assumed for the frequency band generated by the fans  7  and  11  which are suction side (exhaust side) coolers. By employing such a structure, both the noise canceling function and the original function of the sound outputting apparatus can be established neither too much nor too less without affecting the original sound other than the suction sound (exhaust sound). 
     (Ninth Embodiment) 
     A ninth embodiment is to enhance a low sound portion in addition to the original sound reduction function by further providing a basslef port  39 ,  39 - 2  in an attachable/detachable silencer. FIG. 8 is a sectional view showing one example of a projection type projector apparatus with a silencer which is a ninth embodiment according to the present invention. 
     The above-mentioned silencer with the sound outputting apparatus shown in FIG. 7 or the like takes a form approximating to a structure of a general speaker box where the box of the silencer is utilized as an enclosure, when viewed from another angle. Here, when an arbitrary bass reinforcing port, namely a basslef port  39 ,  39 - 2  is provided within a range meeting the cooling condition, this silencer functions as a noise damping apparatus and simultaneously it can also be established as a sound outputting apparatus excellent in a bass region regenerating ability, which has the basslef port. 
     Accordingly, the ninth embodiment is characterized by providing an attachable/detachable silencer and providing a sound outputting apparatus with a reinforced bass regenerating ability. According to the present invention, there can be provided a projection type projector apparatus which is provided with a silencer serving as an sound apparatus with an excellent sound performance according to the conditions of use while a priority of a mobile operation is maintained when the silencer is detached. 
     As mentioned above, according to the present invention, there is provided a projection type projector apparatus where, by making a silencer attachable/detachable, a sufficient quietness can be achieved by attaching a silencer to the main body of the projection type projector apparatus according to necessity without large-sizing the main body and a portability of the apparatus can be obtained by separating this silencer from the main body when the silencer is not required, and such an attachable/detachable silencer. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.