Abstract:
A picture-exhibiting device with an audio system which can be used to demonstrate paintings or photos. The picture-exhibiting device with an audio system includes a frame, a picture fixed on the frame, an electret speaker positioned on the backside of the picture, a fixer disposed at a back side of the picture, a back frame fixed on the frame, a cover covering part of the back frame and the electret speaker, a post amplifier coupling the electret speaker, and an audio signal provider coupling the post amplifier.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a picture exhibiting device with an audio system, and more particularly to a picture exhibiting device which can play music and can be a decoration. 
         [0003]    2. Description of the Prior Art 
         [0004]    Currently, music becomes a big form of entertainment for people in daily life. Besides wanting a good music playing device, people also pay attention to the audio quality. For example, Dolby Digital is the common version containing up to six discrete channels of sound. It can provide surround sound that envelops the movie watching or music listening audience, making them feel like they&#39;re in the middle of the action or concert. 
         [0005]    True surround sound formats rely on dedicated speakers that literally and physically surround the audience. Therefore, six speakers are needed to play Dolby Digital 5.1, for example, a pair of front speakers, a center speaker, a pair of rear speakers, and a subwoofer. 
         [0006]    However, the sizes of the speakers are heavy and big, therefore, the speakers can only be disposed on the ground. As a result, space in the house is occupied by the speakers, and the housing decoration becomes messy. 
       SUMMARY OF THE INVENTION 
       [0007]    It is one of the objects of the present invention to provide a picture exhibiting device with an audio system in order to solve the above-mentioned prior art problems. 
         [0008]    To these ends, according to one aspect of the present invention, the picture-exhibiting device with an audio system includes a frame, a picture fixed on the frame and a first electret speaker disposed at a backside of the picture. 
         [0009]    The picture-exhibiting device with an audio system can combine with photos or paintings, therefore, the room space can be saved. Moreover, the picture-exhibiting device is easy to fix on any object, and has a nice appearance. Besides, it is most suitable for use in building a home theater. 
         [0010]    These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings: 
           [0012]      FIG. 1  depicts a picture-exhibiting device with an audio system schematically according to a first preferred embodiment of the present invention. 
           [0013]      FIG. 2  depicts a picture-exhibiting device with an audio system schematically according to a second preferred embodiment of the present invention. 
           [0014]      FIG. 3  depicts a structure of the electret speaker schematically according to a preferred embodiment of the present invention. 
           [0015]      FIG. 4  shows the application of the picture-exhibiting device with an audio system according to a preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]      FIG. 1  depicts a picture-exhibiting device with an audio system schematically according to a first preferred embodiment of the present invention. As shown in  FIG. 1 , a picture-exhibiting device with an audio system  10  includes a frame  12 , a picture  14  and at least one electret speaker  16 . The picture-exhibiting device with an audio system  10  can display a painting or a photograph. More specifically speaking, the frame  12  can be a painting frame or a photo frame. The picture  14  can be a canvas, a paper, or a photograph. For example, the picture  14  can be an oil painting, a Chinese painting, a wafer painting, a colorful photo, or a black and white photo.  FIG. 1  shows the picture-exhibiting device with audio system  10  displaying a painting. The picture  14  has a front side  20  and a back side  22 . The front side  20  faces to an observer  24 , and the back side  22  faces away from the observer  24 . In addition, the picture  14  is fixed on the frame  12 . The picture  14  can be a sound-penetrating material which can let sound pass through the material clearly. For example, the sound-penetrating material can be a canvas, a paper, a plastic punch plate or a cloth. 
         [0017]    The electret speaker  16  can be fixed on the back side  22  of the picture  14  by a fixer  26  such as Velcro, double-sided tape or a hot-melt adhesive. However, because the electret speaker  16  is a film speaker, there must be enough air gap between the picture  14  and the electret speaker  16  or the picture  14  itself must be an air-permeable material. Otherwise, the electret speaker  16  will not have enough room to vibrate. Therefore, preferably, a spacer  28  can be optionally disposed on the back side  22  of the picture  14  to make sure the electret speaker  16  has enough room to vibrate. The electret speaker  16  can be fixed on the back side  22  of the spacer  28  by the fixer  26  such as Velcro, double-sided tape or a hot-melt adhesive. In another way, the electret speaker  16  can be fixed on the back side  22  of the spacer  28  by wood chips with a screw or plastic boards with a screw. The thickness of the spacer  28  can offer a proper distance to separate the electret speaker  16  and the picture  14 . According to the first preferred embodiment, the proper distance is preferably between 0 cm to 3 cm. In this way, the electret speaker  16  has a proper vibration space. 
         [0018]    Moreover, a back frame  30  can be fixed on the frame  12  and a cover  32  can be disposed on the back side  22  of the picture  14  to cover part of the back frame  30 , the spacer  28  and the electret speaker  16 . According to the first preferred embodiment, the thickness of the picture-exhibiting device with an audio system  10  is between 3 mm to 15 cm. 
         [0019]    The electret speaker  16  needs to couple to a post amplifier  34  such as a converter. The post amplifier  34  couples to an audio signal provider  36 . The post amplifier  34  may amplify the signal sent from the audio signal provider  36 . The post amplifier  34  can be disposed between the spacer  28  and the cover  32 . The audio signal provider  36  may be a DVD player, a CD player, an MP3 player, or a computer. The resistance of the post amplifier  34  is between 1Ω to 50Ω, and the conversion ratio of the post amplifier  34  is between 5 to 200. The input inductance of the post amplifier  34  is between 0.1 mH to 100 mH, and the output inductance of the post amplifier  34  is between 1 H to 100 H. The post amplifier  34  can also be covered by the back frame  30  and the cover  32 . 
         [0020]    The signals can transfer between the electret speaker  16 , the post amplifier  34 , and the audio signal provider  36  by wires, Bluetooth, or a wireless transmission module. In  FIG. 1 , the signal is transferred through wires. 
         [0021]    It should be noted that there can be many speakers with different frequency ranges disposed at the back side  22  of the picture  14 . For instance, the electret speaker  16  can be a low and medium frequency speaker with a frequency between 100 Hz to 12 KHz, and the capacitance of the electret speaker  16  is between 30 pF to 20 nF. Another electret speaker  18  which is a high frequency speaker can also be disposed at the back side  22  of the picture  14 . The frequency of the electret speaker  18  is between 2 kHz to 30 KHz, and the capacitance of the electret speaker  18  is between 30 pF to 1 nF. The electret speaker  18  couples to the post amplifier  34  as well. With the electret speakers  16 ,  18 , the picture-exhibiting device with an audio system provides a wider range of frequencies. 
         [0022]    In addition, the number of the electret speakers  16  with the same frequency range can be more than one. Based on different requirements, numerous electret speakers  16  can be disposed at the back side  22  of the picture  14 . For example, there can be three low and medium frequency speakers disposed at the back side  22  of the picture  14 . In the same way, there can also be numerous high frequency speakers disposed at the back side  22  of the picture  14 . 
         [0023]      FIG. 2  depict a picture-exhibiting device with an audio system schematically according to a second preferred embodiment of the present invention, wherein like or similar features one to another will ordinarily be described with like reference numerals. The picture-exhibiting device with an audio system is utilized for displaying a photo. Most elements in the second preferred embodiment have like feature as that in the first preferred embodiment. Therefore, please refer to the first preferred embodiment for the description of the like elements in the second preferred embodiment. The difference between the first and the second preferred embodiments is that there is no back frame, but a supporter  130  on the picture-exhibiting device with an audio system  10  in the second preferred embodiment. The supporter  130  includes a frame  132  and a stand  134 . Conventionally, the position of a conventional stand will block the sound. Therefore, in the present invention, the stand  134  is disposed at the bottom of the electret speaker  18 . Furthermore, the post amplifier  34  is disposed outside of the picture-exhibiting device with audio system  10  rather than the space between the frame  12  and the supporter  130 . Moreover, the signal between the electret speakers  16 ,  18 , the post amplifier  34 , and the audio signal provider  36  is transferred by Bluetooth. 
         [0024]      FIG. 3  depicts a structure of the electret speaker schematically according to a preferred embodiment of the present invention. As shown in  FIG. 3 , the electret speaker  16  includes a first electrode  38  and a second electrode  40  used for receiving an audio signal sending from the post amplifier  34 . A first electret membrane  42  and a second electret membrane  44  are disposed between the first and the second electrodes  38 ,  40 . A conductive layer  46  is disposed between the first electret membrane  42  and the second electret membrane  44 . After the audio signal is input into the first electrode  38  and the second electrode  40 , the first electret membrane  42 , the second electret membrane  44  and the conductive layer  46  are driven to vibrate and make sounds. The capacitance of the electret speaker  16  is between 30 pF to 20 nF. 
         [0025]      FIG. 4  shows the application of the picture-exhibiting device with audio system according to a preferred embodiment of the present invention. As shown in  FIG. 4 , numerous picture-exhibiting devices with audio system  10  are disposed in a space  48 . Each picture-exhibiting device with an audio system  10  connects to the audio signal provider  36  by Bluetooth. 
         [0026]    The electret speaker of the present invention is light and thin, therefore it&#39;s easy to fix on any object. Even when combined with the picture frames, the look of the picture frames is still beautiful. Besides, the observer can enjoy music when appreciating a picture. Moreover, the picture-exhibiting device with an audio system is space-saving. No more huge stereo set is needed. In addition, the electret speaker of the present invention can not only be combined with the picture frame but also with a screen, wall paper, or any other domestic decorations. 
         [0027]    Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.