Patent Application
20150237426
The present disclosure is generally related to audio reproduction for mobile computing devices and, more particularly, to providing a moving-screen audio transducer while allowing enhanced clarity and frequency response of the audio system.
Most mobile device users are aware that sophisticated hardware and software are used to drive their device display. However, far fewer users may realize that providing audio on such a device also raises daunting challenges. For users that employ earphones or headphones when listening to their device, the transduction of audio data into sound is left to the earphone or headphone manufacturer. However, for audio that needs to be projected directly from the device itself, e.g., during a hands-free call, the phone itself must be equipped for the transduction of audio data into sound.
Traditionally, mobile devices have employed simple speaker technology. However, the continuing decrease in device size and weight have lead to an alternative speaker technique, namely, the use of the device display glass itself as a speaker membrane or surface. While this may be referred to as a moving-screen technology, it might more accurately be considered a vibrating-screen technology; these terms may be used interchangeably herein.
In the moving-screen technique, the glass display acts as a transducer for an audio signal. This provides certain benefits, e.g., the user can place his ear essentially anywhere, during a hands-free or ordinary call, and still hear the conversation. However, there are also substantial drawbacks: Glass displays are designed primarily for visual display and not for audio transduction and thus do not inherently posses the properties required for high quality sound reproduction.
Thus, for example, a single transducer applied to a display screen tends to have an audio response characterized by acoustic peaks and valleys. In addition, this type of moving-screen technology often results in poor reproduction of low-frequency audio. Moreover, since the display-screen production process is not adapted to test or control audio-response characteristics, there is substantial variation in frequency response from screen to screen. While these shortcomings can manifest themselves in the form of poor audio quality from the user's standpoint, they may also be severe enough to prevent industry certification or approval of the device.
It will be appreciated that this Background section represents the observations of the inventors, and these observations are provided simply as a research guide to the reader. As such, nothing in this Background section is intended to represent, or to fully describe, any particular prior art.
While the appended claims set forth the features of the present techniques with particularity, these techniques, together with their objects and advantages, may be best understood from the following detailed description taken in conjunction with the accompanying drawings of which:
Before providing a detailed discussion of the figures, a brief overview is given to guide the reader. In an embodiment, an audio-transducer system includes a first transducer formed with the display glass of a device and a second dynamic audio transducer near the top of the device. The second transducer supplements the sound output of the device while also compensating for frequency anomalies of the glass structure. Not only does this system provide an improved user experience, but it also allows the device to achieve adequate frequency response for Type Approval. In an embodiment, the second dynamic audio transducer is equalized so that the sum of its response and the glass's response meet the required mask.
In an embodiment, the display movement near the perimeter is limited. In a further embodiment, the dynamic audio transducer is used to fill in notches in the glass response or to extend the bass response.
Turning now to a more detailed discussion in conjunction with the attached figures, techniques of the present disclosure are illustrated as being implemented in a suitable environment. The following description is based on embodiments of the disclosed principles and should not be taken as limiting the claims with regard to alternative embodiments that are not explicitly described herein.
The schematic diagram of
In the illustrated embodiment, the components of the user device 110 include a display screen 120 having associated therewith a display-screen audio actuator 125. These elements are discussed in greater detail later with reference to other figures. A dynamic audio transducer 130 is also included in the illustrated embodiment. The user device 110 further incorporates a processor 140, a memory 150, one or more audio drivers 160, and one or more input components 170.
The processor 140 can be any of a microprocessor, microcomputer, application-specific integrated circuit, or the like. For example, the processor 140 can be implemented by one or more microprocessors or controllers from any desired family or manufacturer. Similarly, the memory 150 may reside on the same integrated circuit as the processor 140. Additionally or alternatively, the memory 150 may be accessed via a network, e.g., via cloud-based storage. The memory 150 may include a random-access memory. Additionally or alternatively, the memory 150 may include a read-only memory (i.e., a hard drive, flash memory, or any other desired type of memory device).
The information that is stored by the memory 150 can include code associated with one or more operating systems or applications as well as informational data, e.g., program parameters, process data, etc. The operating system and applications are typically implemented via executable instructions stored in a non-transitory computer- readable medium (e.g., memory 150) to control basic functions of the electronic device 110. Such functions may include, for example, interaction among various internal components and storage and retrieval of applications and data to and from the memory 150.
The device 110 may also include a component interface 180 to provide a direct connection to auxiliary components or accessories and a power supply 190, such as a battery, for providing power to the device components. In an embodiment, all or some of the internal components communicate with one another by way of one or more internal communication links 195, such as an internal bus.
Further with respect to the applications, these typically utilize the operating system to provide more specific functionality, such as file-system service and handling of protected and unprotected data stored in the memory 150. Although many applications may govern standard or required functionality of the user device 110, in many cases applications govern optional or specialized functionality, which can be provided, in some cases, by third-party vendors unrelated to the device manufacturer.
Finally, with respect to informational data, e.g., program parameters and process data, this non-executable information can be referenced, manipulated, or written by the operating system or an application. Such informational data can include, for example, data that are preprogrammed into the device 110 during manufacture, data that are created by the device 110, or any of a variety of types of information uploaded to, downloaded from, or otherwise accessed at servers or other devices with which the device 110 is in communication during its ongoing operation.
In an embodiment, the device 110 is programmed such that the processor 140 and memory 150 interact with the other components of the device 110 to perform a variety of functions. The processor 140 may include or implement various modules and execute programs for initiating different activities such as launching an application, transferring data, and toggling through various graphical user-interface objects (e.g., toggling through various icons that are linked to executable applications).
The illustrated device also includes a display screen 205, which is a touch screen in an embodiment. Although not visible in
As shown in
Within the context of a device such as that described with reference to
In the illustrated embodiment, the audio system 300 includes an audio decoding or decompression module 301. The decoding or decompression module 301 provides a digital input 302 to an audio-driver module 303 which creates one or more driving signals 304, 305. While the driving signals 304, 305 are shown in
In an embodiment, the first audio transducer 306 comprises a moving-screen transducer comprising an actuator 308 and a screen 205, which may be the display screen of the host device. The actuator 308 may be of any suitable type capable of causing a vibration of the screen 205 at human-audible frequencies and suitable amplitudes. Suitable actuators include piezo-electric actuators, electromagnetic actuators, and the like.
In an embodiment, the driving signals 304, 305 convey essentially identical audio data, with the exception of possible differences in the format, amplitude, and frequency envelope of the data. For example, depending upon the actuators used, the first driving signal 304 may be a current signal with an amplitude and envelope configured to drive an electromagnetic actuator 308 affixed to a screen 205, the system having a response notch in the middle of the audible range. In contrast, the second driving signal 305 may be a voltage signal with an amplitude and envelope configured to drive an isolated piezo actuator having a flat response. Nevertheless, the outputs of the first and second transducers 306, 307 may sound essentially the same to the user, with minor differences in overall amplitude and frequency response. It will be appreciated that there is no requirement for any signal to be of any particular type, e.g., voltage or current, and that the foregoing examples are simply given for illustrative purposes.
In an alternative embodiment, the driving signals 304, 305 are identical, and are thus not configured to account for the frequency response of the relevant transducers 306, 307.
As noted above, the combined frequency response of a screen and its actuator may be inherently poor. For example, this system may have significant notching in its frequency response. Furthermore, the placement of the screen against the user's cheek during a call may also affect the system's frequency response, e.g., by damping certain frequencies or frequency ranges.
To this end, in an embodiment, the second transducer 307 is an electrodynamic speaker, that is, a speaker that uses a driven coil to move a coil or magnet that is connected to a diaphragm (e.g., a speaker cone). The driven coil is selectively energized within a magnetic field to oscillate the speaker cone in a manner that reproduces a sound of interest. The magnetic field may be provided by a permanent magnet or by a field coil. In a further embodiment the electrodynamic speaker is driven in a manner calculated to at least partially offset frequency notches in the response of the screen 205 (acting as part of the audio transducer 306).
Continuing,
While the pleasant response of the second transducer 307 may somewhat mask the poor response of the first transducer 306, the defects in the response of the screen-based first transducer 306 may still be audible. To that end, in an embodiment, the response of the second transducer 307 is artificially modified to offset the defects in the response of the first transducer 306.
In an embodiment, the modification of the response of the second transducer 307 is performed via a mapping executed before the communications device is sold at retail. In a further embodiment, a user may perform an initial or subsequent mapping using an application or function loaded on the device. Depending upon the consistency of response among various screen-based transducers such as transducer 306, it is also possible for the same response mapping to be applied by the manufacturer on each device that uses the same screen.
In an embodiment, one or both transducers 306, 307 are selectively disabled depending upon the usage mode of the device. For example, during a hands-free call, both transducers 306, 307 may be active. However, when the device is held to the user's ear during a call, the first transducer 306 may be disabled. In addition, the sound volume from the second transducer 307 may be reduced in this situation.
In an embodiment, the second transducer 307 is equalized so that the sum of its response and the glass's response meet a specified mask. In another embodiment, the display movement near the perimeter is limited. In yet another embodiment, the second transducer 307 is used to extend the bass response of the device. Although the examples given show the second transducer 307 on the front face of the device near the top, the second transducer 307 may be placed at another location if desired. Further, a third, fourth, or subsequent transducer may also be used without departing from the scope of the disclosed principles.
It will be appreciated that the disclosed principles allow the use of a screen-based transducer to produce sound with respect to a mobile device, while also allowing the manufacturer to provide acceptable frequency response for the device as a whole. However, in view of the many possible embodiments to which the principles of the present discussion may be applied, it should be recognized that the embodiments described herein with respect to the drawing figures are meant to be illustrative only and should not be taken as limiting the scope of the claims. Therefore, the techniques as described herein contemplate all such embodiments as may come within the scope of the following claims and equivalents thereof.
