1. Field of the Invention
The present invention relates generally to speaker sets for portable electronic products and, more particularly, to a speaker set for an electronic product, which makes the electronic product compact and produces high quality sound.
2. Description of Related Art
Portable electronic products, such as mobile phones, CD players, MP3s, PDAs (Personal Digital Assistants) and the like, have decreased both in size and weight over the past few years and are becoming ever more popular with travelers. This demand for smaller size with ever-increasing capability has required a tremendous effort to miniaturize many of the components contained within the device.
However, portable electronic products being designed today require multi-media features and provide the user with the same enjoyable experience as that experienced with conventional high quality desktop systems. Thus, the sounds emanating from a portable electronic product should provide as full a harmonic content as is contained in the original sound. The production of low frequency sounds requires a large acoustic chamber for the movement of a large mass of air. As the device is reduced in size, the size of the acoustic chamber of the speaker set and the maximum power the speaker can handle are also accordingly reduced, resulting in both a reduction in loudness as well as a poorer overall quality of sound. However, increasing the device size to increase the size of the acoustic chamber for the speaker is very undesirable since it would strongly detract from the very characteristics that have helped to make these devices popular, namely their size and weight. Thus the size of the device is at odds with sound quality of the speaker.
Therefore, a portable electronic product having compact size and good sound quality is highly needed.
The present invention relates, in one respect, to an electronic product having compact size and good sound quality, and in another aspect, to a speaker set for the electronic product. According to a preferred embodiment of the present invention, the electronic product includes a casing containing a speaker set therein. The speaker set includes a hollow shell and a loudspeaker. The loudspeaker is accommodated in the shell, dividing an inner space of the shell into a first resonance chamber and a second resonance chamber. The loudspeaker has first tone holes communicating with the first resonance chamber and second tone holes communicating with the second resonance chamber. The first resonance chamber communicates with the second resonance chamber via at least an inverted tube.
Other advantages and novel features of the present invention will become more apparent from the following detailed description of preferred embodiment when taken in conjunction with the accompanying drawings.
Many aspects of the present invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views:
Referring to
Referring to
Referring also to
The shell 60 of the speaker set 20 further includes an inverted tube 69 disposed in the third chamber 60c and communicating the third chamber 60c with the second chamber 60d. The inverted tube 69 has a semicircular shaped cross section and cooperatively defines an acoustic passage with a top surface of the base wall 61. The inverted tube 69 is L-shaped in profile and has two openings (not labeled) respectively communicating with a hole (not labeled) defined in a bottom of the spacing plate 68 and facing towards the vent hole 651 of the sidewall 65.
Particularly referring to
Referring to
In assembly of the speaker set 20 in the mobile phone 100, the printed circuit board 30 is disposed in the casing 10 of the mobile phone 100. The loudspeaker 50 is disposed in the annular wall 66 and mounted on the flange 661. The hollow frame 40 is located on an open side (front side) of the shell 60, with rear surfaces of the outer and inner frames 41, 42 contacting with the corresponding front surfaces of the sidewalls 62, 63, 64, 65, of the first edge portion 664 of the annular wall 66 and of the spacing plates 67, 68. The speaker set 20 and the hollow frame 40 are arranged in the casing 10 of the mobile phone 100, with front surfaces of the outer and inner frames 41, 42 contacting with a rear surface of the printed circuit board 30. Therefore, two Helmholtz resonance chambers, i.e., a first resonance chamber 61a communicating with the first tone holes 52 of the loudspeaker 50 and consisting of the rear chamber 60a and the third chamber 60c, and a second resonance chamber 61b communicating with the second tone holes 54 of the loudspeaker 50 and consisting of the front chamber 60b and the second chamber 60d, are formed in the shell 60.
In the assembly of the speaker set 20 in the mobile phone 100, there are adhesives filled in interstices formed between the frame 40 and the printed circuit board 30 and the shell 60 so as to keep a hermetical contact therebetween. Therefore, the sound waves in the second and third chambers 60d, 60c can not leak from the interstices, and the first resonance chamber 61a accordingly communicates with the second resonance chamber 61b via the inverted tube 69 only. The sound waves emitted from the first and second tone holes 52, 54 of the loudspeaker 50 are respectively transmitted to and resonate with air in the first and second resonance chambers 61a, 61b at the natural frequencies thereof. The sound waves in the second resonance chamber 61b are then transmitted into the first resonance chamber 61a via the inverted tube 69 and further resonate with the air in the first resonance chamber 61a. Finally, the sound waves are transmitted to the surrounding environment via the vent holes 651, 132 of sidewall 65 of the shell 60 and the casing 10.
In the present mobile phone 100, the inverted tube 69 inverts phases of the sound waves in the second resonance chamber 61b into phases which are coincident with phases of the sound waves in the first resonance chamber 61a. Thus, the sound waves transmitted towards the first resonance chamber 61a from the second resonance chamber 61b are superposed on the sound waves in the first resonance chamber 61a, which widens the frequency bandwidth of the sound waves emitted from the shell 60. Accordingly, a crest of a frequency response curve of the sound waves emitting from the shell 60 moves towards a lower frequency as compared to a crest of a frequency response curve of sound waves emitting from the shell 60 without the inverted tube 69 disposed therein. Therefore, the lower frequency range of the sound emitted from the mobile phone 100 is widened and the low-frequency sound emitted from the mobile phone 100 is boosted which increases sound quality of the mobile phone 100. When the acoustic field of the single first and second resonance chambers 61a, 61b and the shell 60 including the communicated first and second resonance chambers 61a, 61b are simulated by using SYSNOISE software distributed by LMS North America, 5455 Corporate Drive, Suite 303, Troy, Mich. 48098, it was found that the response frequency of the singular first resonance chamber 61a is about 3000 HZ, the response frequency of the singular second resonance chamber 61b is about 6500 HZ, and the response frequency of the shell 60 is about 494 HZ. The response frequency of the shell 60 is responsive to ear, thus allowing high quality sounds to be made by the present mobile phone 100.
In addition, the opening of the inverted tube 69 faces to the vent hole 651 of the sidewall 65. This decreases distance of spread of the sound waves emitted from the inverted tube 69 towards the surrounding environment, which decreases energy loss of the sound waves and therefore increases sound quality of the mobile phone 100. Moreover, the hollow frame 40 weakens the vibration caused by the sound waves transferring towards the printed circuit board 30, which prevents the quality of the sound from being impaired by vibration. The hollow frame 40 has hermetic seal with the printed circuit board 30 and the shell 60 of the speaker set 20, which prevents the sounds from leakage from interstices formed between the printed circuit board 30 and the shell 60 of the speaker set 20.
Referring to
Referring to
The present speaker set 20 is disposed in a mobile phone 100. Alternatively, the speaker set 20 is can be used in other kinds of portable electronic products, such as PDAs (personal digital assistants), CD players, MP3s and MP4s. The inverted tube 69/79/89 of the speaker set 20 helps the portable electronic products be compact as well as having good sound quality.
It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of portions within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
This application is related to co-pending U.S. patent application Ser. No. 11/611,709, filed on Dec. 25, 2006, and entitled “SPEAKER SET AND MOBILE PHONE INCORPORATING THE SAME”, and co-pending U.S. patent application Ser. No. ______, entitled “SPEAKER SET FOR ELECTRONIC PRODUCT”, and filed on the same date with the present application. The present application and the co-pending applications are assigned to the same assignee. The disclosures of the above-identified applications are incorporated herein by reference.