Patent Publication Number: US-2018048846-A1

Title: Image display apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Pursuant to 35 U.S.C. §119, this application claims the benefit of earlier filing date and right of priority to Korean Application No(s). 10-2016-0123136, filed on Sep. 26, 2016, and also claims the benefit of U.S. Provisional Application Ser. No. 62/366,640, filed on Jul. 26, 2016, the contents of which are all incorporated by reference herein in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an image display apparatus, and more particularly, to an image display apparatus for reducing acoustic interference between a first sound directed in a front direction and a second sound directed in a ceiling direction. 
     2. Description of the Related Art 
     As it transmits digital audio and video signals, digital broadcasting offers many advantages over analog broadcasting, such as robustness against noise, less data loss, ease of error correction, and the ability to provide high-definition, clear images. Digital broadcasting also allows interactive viewer services, compared to analog broadcasting. 
     Along with user demands for sounds that offer a feeling of presence, the performance of a speaker has been improved in image display apparatuses. 
     SUMMARY OF THE INVENTION 
     Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an image display apparatus for reducing acoustic interference between a first sound directed in a front direction and a second sound directed in a ceiling direction. 
     In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of an image display apparatus including a display, a first speaker unit to output a first sound in a front direction, and a second speaker unit to output a second sound in a ceiling direction. The second speaker unit includes an array speaker with a plurality of speakers. 
     In accordance with another aspect of the present invention, there is provided an image display apparatus including a display, a first speaker unit to output a first sound in a front direction, and a second speaker unit to output a second sound in a ceiling direction. The second speaker unit includes an array speaker with a plurality of speakers, and a frequency band of the second sound is higher than a frequency band of the first sound. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a view illustrating an image display apparatus according to an embodiment of the present invention; 
         FIG. 2  is a block diagram of an image display apparatus according to an embodiment of the present invention; 
         FIG. 3  is a block diagram of a controller illustrated in  FIG. 2 ; 
         FIG. 4A  is a view illustrating a method for controlling a remote controller illustrated in  FIG. 2 ; 
         FIG. 4B  is a block diagram of the remote controller illustrated in  FIG. 2 ; 
         FIGS. 5A, 5B, and 5C  are views illustrating various sounds output from an image display apparatus; 
         FIGS. 6A to 6E  are block diagrams of an audio processor, a first speaker unit, and a second speaker unit according to various embodiments of the present invention; 
         FIGS. 7A and 7B  are graphs illustrating frequency bands of sounds output from a first speaker unit and a second speaker unit, respectively; 
         FIG. 8A  is a block diagram of an audio processor, a first speaker unit, and a second speaker unit according to another embodiment of the present invention; 
         FIG. 8B  is graphs illustrating frequency bands of sounds output from the first speaker unit and the second speaker unit illustrated in  FIG. 8A ; 
         FIG. 9A  is timing diagrams of audio signals applied to a second speaker; 
         FIG. 9B  is a view illustrating sounds output from the second speaker unit according to the audio signals illustrated in  FIG. 9A ; 
         FIGS. 10A to 11D  are views illustrating pop-up and tilting of a second speaker unit; and 
         FIGS. 12A and 12B  are views comparing a general speaker and an array speaker in terms of directivity. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will be described below with reference to the attached drawings. 
     The terms “module” and “unit” used to signify components are used herein to help the understanding of the components and thus they should not be considered as having specific meanings or roles. Accordingly, the terms “module” and “unit” may be used interchangeably. 
       FIG. 1  is a view illustrating an image display apparatus according to an embodiment of the present invention. 
     Referring to  FIG. 1 , an image display apparatus  100  according to an embodiment of the present invention may include a display  180 , a first speaker unit  185   a  for outputting a first sound in a front direction, and a second speaker unit  185   b  for outputting a second sound in a ceiling direction. The second speaker unit  185   b  may include an array speaker SHa with a plurality of speakers Sa 1  to Sa 7 . Therefore, acoustic interference between the first sound in the front direction and the second sound in the ceiling direction may be reduced. The first speaker unit  185   a  and the second speaker unit  185   b  are shown in  FIG. 1  as residing in a signal processor  300 , by way of example. 
     The signal processor  300  may process a video signal and output the processed video signal to the display  180 . 
     The signal processor  300  may also process an audio signal and output the processed audio signal to the first speaker unit  185   a  and the second speaker unit  185   b.    
     Meanwhile, the signal processor  300  may conceptually include a broadcasting receiver  105 , a memory  140 , a controller  170 , a user input interface  150 , and a power supply  190  illustrated in  FIG. 2 . That is, the display  180  may be excluded from the signal processor  300  in concept. 
     In  FIG. 1 , speakers SFa and SFb of the first speaker unit  185   a  are arranged on a front surface of the signal processor  300 , and array speakers SHa and SHb of the second speaker unit  185   b  are arranged on top of the signal processor  300 , by way of example. 
     The first sound from the first speaker unit  185   a  is output toward a user, whereas the second sound from the second speaker unit  185   b  is output toward a ceiling, reflected from the ceiling, and then reaches the user. 
     The first sound and the second sound are directed in different directions, and it is preferred that acoustic interference does not occur between the first sound and the second sound. 
     Accordingly, to improve particularly the directivity of the second sound, the second speaker unit  185   b  includes the array antenna SHa with the plurality of speakers Sa 1  to Sa 7  in the present invention. 
     While the array speaker SHa includes 7 speakers Sa 1  to Sa 7  in  FIG. 1 , by way of example, various modifications may be made to the array speaker SHa. Preferably, the array speaker SHa includes at least three speakers. 
     The directivity of an array antenna is more excellent than that of a general speaker, as described later with reference to  FIG. 12B . Accordingly, the use of the array speaker SHa may lead to reduction of acoustic interference between the first sound directed in the front direction and the second sound directed in the ceiling direction. 
     The directivity of the second sound may be improved by setting the frequency band of the second sound from the second speaker unit  185   b  to be narrower than the frequency band of the first sound from the first speaker unit  185   a , thereby reducing the acoustic interference between the first sound directed in the front direction and the second sound directed in the ceiling direction. 
     Particularly, if the gain of a power amplifier in the second speaker unit  185   b  is set to be larger than the gain of a power amplifier in the first speaker unit  185   a , the user may listen to the second sound farther from the user, uniformly together with the first sound. 
     According to another embodiment of the present invention, the image display apparatus  100  includes the display  180 , the first speaker unit  185   a  for outputting a first sound in a front direction, and the second speaker unit  185   b  for outputting a second sound in a ceiling direction. The second speaker unit  185   b  includes the array speaker SHa with the plurality of speakers Sa 1  to Sa 7 . As the frequency band of the second sound is higher than the frequency band of the first sound, acoustic interference between the first sound in the front direction and the second sound in the ceiling direction may be reduced. 
     Particularly, the second speaker unit  185   b  outputs a high-frequency, high-directivity sound, thereby reducing the acoustic interference between the first sound in the front direction and the second sound in the ceiling direction. 
       FIG. 2  is a block diagram of an image display apparatus according to an embodiment of the present invention. 
     Referring to  FIG. 2 , the image display apparatus  100  according to the embodiment of the present invention may include the broadcasting receiver  105 , an external device interface  130 , the memory  140 , the user input interface  150 , a sensor unit (not shown), the controller  170 , the display  180 , and an audio output unit  185 . 
     The broadcasting receiver  105  may include a tuner unit  110 , a demodulator  120 , and a network interface  135 . As needed, the broadcasting receiver  105  may be configured so as to include only both the tuner unit  110  and the demodulator  120  or only the network interface  135 . 
     The broadcasting receiver  105  may be configured to include the external device interface  135 , differently from in  FIG. 2 . For example, a broadcast signal from a set-top box may be received through the external device interface  135 . 
     The tuner unit  110  selects a Radio Frequency (RF) broadcast signal corresponding to a channel selected by a user or an RF broadcast signal corresponding to each of pre-stored channels from among a plurality of RF broadcast signals received through an antenna and downconverts the selected RF broadcast signal into a digital Intermediate Frequency (IF) signal or an analog baseband Audio/Video (A/V) signal. 
     For example, if the selected RF broadcast signal is a digital broadcast signal, the tuner unit  110  downconverts the selected RF broadcast signal into a digital IF signal, DIF. On the other hand, if the selected RF broadcast signal is an analog broadcast signal, the tuner unit  110  downconverts the selected RF broadcast signal into an analog baseband A/V signal, CVBS/SIF. That is, the tuner unit  110  may be a hybrid tuner capable of processing not only digital broadcast signals but also analog broadcast signals. The analog baseband A/V signal CVBS/SIF from the tuner unit  110  may be directly input to the controller  170 . 
     The tuner unit  110  may sequentially select a number of RF broadcast signals corresponding to all broadcast channels previously stored in the image display apparatus  100  by a channel add function from a plurality of RF signals received through the antenna and may downconvert the selected RF broadcast signals into IF signals or baseband A/V signals. 
     The tuner unit  110  may include a plurality of tuners for receiving broadcast signals on a plurality of channels. Alternatively, the tuner unit  110  may be implemented into a single tuner for simultaneously receiving broadcast signals on a plurality of channels. 
     The demodulator  120  receives the digital IF signal DIF from the tuner unit  110  and demodulates the digital IF signal DIF. 
     The demodulator  120  may perform demodulation and channel decoding on the digital IF signal DIF, thereby obtaining a stream signal TS. The stream signal TS may be a signal in which a video signal, an audio signal and/or a data signal are multiplexed. 
     The stream signal TS may be input to the controller  170  and thus subjected to demultiplexing and A/V signal processing. The controller  170  outputs the processed video and audio signals to the display  180  and the audio output unit  185 , respectively. 
     The external device interface  130  may transmit data to or receive data from a connected external device. For data transmission and reception, the external device interface  130  may include an A/V Input/Output (I/O) unit (not shown) and/or a wireless communication module (not shown). 
     The external device interface  130  may be connected to an external device such as a Digital Versatile Disk (DVD) player, a Blu-ray player, a game console, a camera, a camcorder, a computer (e.g. a laptop computer), or a set-top box, wirelessly or by wire. Then, the external device interface  130  may transmit and receive signals to and from the external device. 
     The A/V I/O unit of the external device interface  130  may receive video and audio signals from the external device. The wireless communication module of the external device interface  130  may perform short-range wireless communication with other electronic devices. 
     The network interface  135  serves as an interface between the image display apparatus  100  and a wired/wireless network such as the Internet. For example, the network interface  135  may receive contents or data from the Internet or from a Contents Provider (CP) or a Network Provider (NP) over a network. 
     The memory  140  may store programs necessary for the controller  170  to process and control signals, and may also store processed video, audio, and data signals. 
     The memory  140  may also temporarily store a video, audio and/or data signal received from the external device interface  130 . The memory  140  may store information about broadcast channels by the channel-add function such as a channel map. 
     While the memory  140  is shown in  FIG. 2  as configured separately from the controller  170 , to which the present invention is not limited, the memory  140  may be incorporated into the controller  170 , for example. 
     The user input interface  150  transmits a signal received from the user to the controller  170  or transmits a signal received from the controller  170  to the user. 
     For example, the user input interface  150  may receive user input signals such as a power-on/off signal, a channel selection signal, and a screen setting signal from a remote controller  200 , provide the controller  170  with user input signals received from local keys (not shown), such as inputs of a power key, a channel key, a volume key, and a setting key, transmit a user input signal received from the sensor unit (not shown) for sensing a user gesture to the controller  170 , or transmit a signal received from the controller  170  to the sensor unit. 
     The controller  170  may demultiplex the stream signal TS received from the tuner unit  110 , the demodulator  120 , or the external device interface  130  into a number of signals and process the demultiplexed signals into audio and video data. 
     The video signal processed by the controller  170  may be displayed as an image corresponding to the video signal on the display  180 . The video signal processed by the controller  170  may also be transmitted to an external output device through the external device interface  130 . 
     The audio signal processed by the controller  170  may be output to the audio output unit  185 . Also, the audio signal processed by the controller  170  may be transmitted to the external output device through the external device interface  130 . 
     While not shown in  FIG. 2 , the controller  170  may include a Demultiplexer (DEMUX) and a video processor, which will be described later with reference to  FIG. 3 . 
     In addition, the controller  170  may provide overall control to the image display apparatus  100 . For example, the controller  170  may control the tuner unit  110  to select an RF broadcast signal corresponding to a user-selected channel or a pre-stored channel. 
     The controller  170  may control the image display apparatus  100  according to a user command received through the user input interface  150  or according to an internal program. 
     The controller  170  may also control the display  180  to display an image. The image displayed on the display  180  may be a Two-Dimensional (2D) or Three-Dimensional (3D) still image or video. 
     The controller  170  may control a particular 2D object in the image displayed on the display  180  to be rendered as a 3D object. For example, the particular 2D object may be at least one of a linked Web page (e.g. from a newspaper, a magazine, etc.), an Electronic Program Guide (EPG), a menu, a widget, an icon, a still image, a video, or text. 
     The 3D object may be processed so as to have a different sense of depth from that of an image displayed on the display  180 . Preferably, the 3D object may be processed to look protruding, compared to the image displayed on the display  180 . 
     The controller  170  may locate the user based on an image captured by a camera unit (not shown). Specifically, the controller  170  may measure the distance (a z-axis coordinate) between the user and the image display apparatus  100 . In addition, the controller  170  may calculate x-axis and y-axis coordinates corresponding to the position of the user on the display  180 . 
     The image display apparatus  100  may further include a channel browsing processor (not shown) for generating thumbnail images corresponding to channel signals or external input signals. The channel browsing processor may extract some of the video frames of each of stream signals TS received from the demodulator  120  or stream signals received from the external device interface  130  and display the extracted video frames on the display  180  as thumbnail images. The thumbnail images may be output to the controller  170  after they are decoded together with a decoded image to a stream. The controller  170  may display a thumbnail list including a plurality of received thumbnail images on the display  180 . 
     The thumbnail list may be displayed on a part of the display  180  with an image displayed on the display  180 , that is, as a compact view, or the thumbnail list may be displayed in full screen on the display  180 . The thumbnail images of the thumbnail list may be updated sequentially. 
     The display  180  generates drive signals by converting a processed video signal, a processed data signal, an On Screen Display (OSD) signal, and a control signal received from the controller  170  or a video signal, a data signal, and a control signal received from the external device interface  130 . 
     The display  180  may be various types of displays such as a Plasma Display Panel (PDP), a Liquid Crystal Display (LCD), an Organic Light-Emitting Diode (OLED) display, and a flexible display. The display  180  may also be a 3D display. 
     For 3D visualization, the display  180  may be configured into an auto-stereoscopic 3D display (glasses-free) or a traditional stereoscopic 3D display (with glasses). 
     Auto-stereoscopy is any method of displaying 3D images without any additional display, for example, special glasses on the part of a user. A lenticular scheme and a parallax barrier scheme are examples of auto-stereoscopic 3D imaging. 
     The traditional stereoscopy requires an additional display as a viewing device (not shown) besides the display  180  in order to display 3D images. The additional display may be a Head Mount Display (HMD) type, a glasses type, etc. 
     As special 3D glasses, polarized glasses operate in a passive manner, whereas shutter glasses operate in an active manner. Also, HMD types may be categorized into passive ones and active ones. 
     The viewing device (not shown) may be 3D glasses that enable the user to view 3D images. The 3D glasses (not shown) may be passive-type polarized glasses, active-type shutter glasses, or an HMD type. 
     The display  180  may also be a touch screen that can be used not only as an output device but also as an input device. 
     The audio output unit  185  may receive a processed audio signal from the controller  170  and output the received audio signal as voice. 
     As described before, the audio output unit  185  may include the first speaker unit  185   a  and the second speaker unit  185   b . The second speaker unit  185   b  may include the array speakers SHa and SHb each including a plurality of speakers. 
     The camera unit (not shown) captures a user. The camera unit may include, but not limited to, a single camera. When needed, the camera unit may include a plurality of cameras. The camera unit may be embedded above the display  180  in the image display apparatus  100 , or may be separately configured. Image information captured by the camera unit may be provided to the controller  170 . 
     The controller  170  may sense a user&#39;s gesture from a captured image received from the camera unit or from signals received from the sensor unit (not shown) alone or in combination. 
     The power supply  190  supplies power across the whole image display apparatus  100 . Particularly, the power supply  190  may supply power to the controller  170  which may be implemented as a System On Chip (SOC), the display  180  for displaying an image, and the audio output unit  185  for outputting an audio signal. 
     Specifically, the power supply  190  may include a converter for converting Alternating Current (AC) power to Direct Current (DC) power, and a DC/DC converter for converting the level of DC power. 
     The remote controller  200  transmits a user input to the user input interface  150 . For the transmission of a user input, the remote controller  200  may operate based on various communication standards such as Bluetooth, RF communication, IR communication, Ultra WideBand (UWB), and ZigBee. In addition, the remote controller  200  may receive a video signal, an audio signal and/or a data signal from the user input interface  150  and may output the received signal as an image or sound. 
     The above-described image display apparatus  100  may be a fixed or mobile digital broadcast receiver. 
     The block diagram of the image display apparatus  100  illustrated in  FIG. 2  is an exemplary embodiment of the present invention. The image display apparatus  100  is shown in  FIG. 2  as having a number of components in a given configuration. However, the image display apparatus  100  may include fewer components or more components than those shown in  FIG. 2 . Also, two or more components of the image display apparatus  100  may be combined into a single component or a single component thereof may be separated into two more components. The functions of the components of the image display apparatus  100  as set forth herein are illustrative in nature and may be modified, for example, to meet the requirements of a given application. 
     Unlike the configuration illustrated in  FIG. 2 , the image display apparatus  100  may be configured so as to receive and playback video contents through the network interface  135  or the external device interface  130 , without the tuner unit  100  and the demodulator  120 . 
     The image display apparatus  100  is an example of an image signal processing apparatus that processes an input or stored image. In another example, the image display apparatus  100  may be implemented into a set-top box without the display  180  and the audio output unit  185  illustrated in  FIG. 2 , a DVD player, a Blue-ray player, a game console, a computer, or the like. 
       FIG. 3  is a block diagram of the controller illustrated in  FIG. 2 . 
     Referring to  FIG. 3 , the controller  170  may include a DEMUX  310 , a video processor  320 , a processor  330 , an OSD generator  340 , a mixer  345 , a Frame Rate Converter (FRC)  350 , and a formatter  360  according to an embodiment of the present invention. The controller  170  may further include an audio processor  370  and a data processor (not shown). 
     The DEMUX  310  demultiplexes an input stream. For example, the DEMUX  310  may demultiplex an MPEG-2 TS into a video signal, an audio signal, and a data signal. The input stream signal may be received from the tuner unit  110 , the demodulator  120 , or the external device interface  130 . 
     The video processor  320  may process the demultiplexed video signal. For video signal processing, the video processor  320  may include a video decoder  325  and a scaler  335 . 
     The video decoder  325  decodes the demultiplexed video signal and the scaler  335  scales the resolution of the decoded video signal so that the video signal may be displayed on the display  180 . 
     The video decoder  325  may be provided with decoders that operate in conformance to various standards. 
     The decoded video signal processed by the video processor  320  may be a 2D video signal, a 3D video signal, or a combination of both. 
     For example, it may be determined whether an external video signal received from an external device or a video signal included in a broadcast signal received from the tuner unit  110  is a 2D signal, a 3D signal, or a combination of both. Accordingly, the controller  170 , particularly the video processor  320  processes the video signal and outputs a 2D video signal, a 3D video signal, or a combination of both. 
     The decoded video signal from the video processor  320  may be a 3D video signal in any of various available formats. For example, the decoded video signal may be a 3D video signal with a color image and a depth image or a 3D video signal including multi-viewpoint image signals. The multi-viewpoint image signals may include, for example, a left-eye image signal and a right-eye image signal. 
     For 3D visualization, available 3D formats are a side-by-side format, a top/down format, a frame sequential format, an interlaced format, and a checker box format. A left-eye image L and a right-eye image R are arranged side by side in the side by side format. The left-eye image L and the right-eye image R are stacked vertically in the top/down format, while they are arranged in time division in the frame sequential format. In the interlaced format, the left-eye image L and the right-eye image R alternate line by line. The left-eye image L and the right-eye image R are mixed on a box basis in the checker box format. 
     The processor  330  may provide overall control to the image display apparatus  100  or the controller  170 . For example, the processor  330  may control the tuner unit  110  to tune to an RF broadcasting corresponding to a user-selected channel or a pre-stored channel. 
     The processor  330  may also control the image display apparatus  100  according to a user command received through the user input interface  150  or an internal program. 
     The processor  330  may control data transmission through the network interface  135  or the external device interface  130 . 
     The processor  330  may control operations of the DEMUX  310 , the video processor  320 , and the OSD generator  340  in the controller  170 . 
     The OSD generator  340  generates an OSD signal autonomously or according to a user input. For example, the OSD generator  340  may generate signals by which a variety of information is displayed as graphics or text on the display  180 , according to user input signals. The OSD signal may include various data such as a User Interface (UI), a variety of menus, widgets, and icons. Also, the OSD signal may include a 2D object and/or a 3D object. 
     Further, the OSD generator  340  may generate a pointer to be displayed on the display  180  based on a pointing signal received from the remote controller  200 . Especially, the pointer may be generated from a pointing signal processor (not shown), which may reside in the OSD generator  340 . Obviously, the pointing signal processor may be configured separately from the OSD generator  240 . 
     The mixer  345  may mix the decoded video signal processed by the video processor  320  with the OSD signal generated from the OSD generator  340 . The OSD signal and the decoded video signal each may include at least one of a 2D signal and a 3D signal. The mixed video signal is provided to the FRC  350 . 
     The FRC  350  may change the frame rate of an input video signal or simply output the video signal without frame rate conversion. 
     The formatter  360  may arrange left-eye and right-eye video frames of the frame rate-converted 3D image. The formatter  360  may also output a synchronization signal Vsync for opening the left and right lenses of a 3D viewing device (not shown). 
     The formatter  360  may receive the mixed signal, that is, the OSD signal and the decoded video signal in combination from the mixer  345  and may separate a 2D video signal from a 3D video signal. 
     The formatter  360  may change the format of the 3D video signal. For example, the formatter  360  may convert a 3D image into one of the foregoing various formats. 
     Meanwhile, the formatter  360  may convert a 2D video signal to a 3D video signal. For example, the formatter  360  may detect edges or a selectable object from the 2D video signal and generate a 3D video signal with an object based on the detected edges or the selectable object. As described before, the 3D video signal may be arranged separately as a left-eye image signal L and a right-eye image signal R. 
     A 3D processor (not shown) may further be provided after the formatter  360 , for processing a signal to exert 3D effects. For enhancing 3D effects, the 3D processor may adjust the brightness, tint, and color of a video signal. For example, the 3D processor may process a video signal in such a manner that a short-distance area may become clear and a long-distance area may become blurry. Meanwhile, this functionality of the 3D processor may be incorporated into the formatter  360  or the video processor  320 . 
     The audio processor  370  of the controller  170  may process the demultiplexed audio signal, or an audio signal of specific contents. For the audio signal processing, the audio processor  370  may have a plurality of decoders. 
     The audio processor  370  of the controller  170  may also adjust the bass, treble, and volume of the audio signal. 
     The data processor (not shown) of the controller  170  may process the data signal obtained by demultiplexing the input stream signal. For example, if the demultiplexed data signal is a coded data signal, the data processor may decode the coded data signal. The coded data signal may be an EPG which includes broadcast information specifying the start time, end time, and the like of a scheduled broadcast TV or radio program. 
     While it is shown in  FIG. 3  that the mixer  345  mixes signals received from the OSD generator  340  and the video processor  320  and then the formatter  360  performs 3D processing on the mixed signal, to which the present invention is not limited, the mixer  345  may be positioned after the formatter  360 . That is, the formatter  360  may subject an output of the video processor  320  to a 3D process, the OSD generator  340  may generate an OSD signal and perform a 3D process on the OSD signal, and then the mixer  345  may mix the processed 3D signals received from the formatter  360  and the OSD generator  340 . 
     The block diagram of the controller  170  illustrated in  FIG. 3  is purely exemplary. Depending upon the specifications of the controller  170  in actual implementation, the components of the controller  170  may be combined or omitted or new components may be added. That is, two or more components are incorporated into one component or one component may be configured as separate components, as needed. 
     Especially, the FRC  350  and the formatter  360  may be configured as separate components or as a single component, outside the controller  170 . 
       FIG. 4A  illustrates a method for controlling the remote controller illustrated in  FIG. 2 . 
     (a) of  FIG. 4A  illustrates a pointer  205  representing movement of the remote controller  200 , displayed on the display  180 . 
     The user may move or rotate the remote controller  200  up and down, side to side ((b) of  FIG. 4A ), and back and forth ((c) of  FIG. 4A ). Since the pointer  205  moves in accordance with the movement of the remote controller  200  in a 3D space, the remote controller  200  may be referred to as a spatial remote controller or a 3D pointing device. 
     Referring to (b) of  FIG. 4A , if the user moves the remote controller  200  to the left, the pointer  205  moves to the left on the display  180 . 
     A sensor of the remote controller  200  detects the movement of the remote controller  200  and transmits motion information corresponding to the result of the detection to the image display apparatus. Then, the image display apparatus may determine the movement of the remote controller  200  based on the motion information received from the remote controller  200 , and calculate the coordinates of a target point to which the pointer  205  should be shifted in accordance with the movement of the remote controller  200  based on the result of the determination. The image display apparatus then displays the pointer  205  at the calculated coordinates. 
     Referring to (c) of  FIG. 4A , while pressing a predetermined button of the remote controller  200 , the user moves the remote controller  200  away from the display  180 . Then, a selected area corresponding to the pointer  205  may be zoomed in and enlarged on the display  180 . On the contrary, if the user moves the remote controller  200  toward the display  180 , the selection area corresponding to the pointer  205  is zoomed out and thus contracted on the display  180 . The opposite case is possible. That is, when the remote controller  200  moves away from the display  180 , the selection area may be zoomed out and when the remote controller  200  approaches the display  180 , the selection area may be zoomed in. 
     With the predetermined button pressed in the remote controller  200 , the up, down, left and right movements of the remote controller  200  may be ignored. That is, when the remote controller  200  moves away from or approaches the display  180 , only the back and forth movements of the remote controller  200  are sensed, while the up, down, left and right movements of the remote controller  200  are ignored. Unless the predetermined button is pressed in the remote controller  200 , the pointer  205  moves in accordance with the up, down, left or right movement of the remote controller  200 . 
     The speed and direction of the pointer  205  may correspond to the speed and direction of the remote controller  200 . 
       FIG. 4B  is a block diagram of the remote controller illustrated in  FIG. 2 . 
     Referring to  FIG. 4B , the remote controller  200  may include a wireless communication module  420 , a user input unit  430 , a sensor unit  440 , an output unit  450 , a power supply  460 , a memory  470 , and a controller  480 . 
     The wireless communication module  420  transmits signals to and/or receives signals from one of image display apparatuses according to embodiments of the present invention. One of the image display apparatuses according to embodiments of the present invention, that is, the image display apparatus  100  will be taken as an example. 
     In the embodiment of the present invention, the wireless communication module  420  may include an RF module  421  for transmitting RF signals to and/or receiving RF signals from the image display apparatus  100  according to an RF communication standard. The wireless communication module  420  may also include an IR module  423  for transmitting IR signals to and/or receiving IR signals from the image display apparatus  100  according to an IR communication standard. 
     The remote controller  200  transmits motion information regarding the movement of the remote controller  200  to the image display apparatus  100  through the RF module  421  in the embodiment of the present invention. 
     The remote controller  200  may also receive signals from the image display apparatus  100  through the RF module  421 . The remote controller  200  may transmit commands, such as a power on/off command, a channel switching command, or a sound volume change command, to the image display apparatus  100  through the IR module  423 , as needed. 
     The user input unit  430  may include a keypad, a plurality of buttons, a touch pad, or a touch screen. The user may enter commands to the image display apparatus  100  by manipulating the user input unit  430 . If the user input unit  430  includes a plurality of hard-key buttons, the user may input various commands to the image display apparatus  100  by pressing the hard-key buttons. If the user input unit  430  includes a touch screen displaying a plurality of soft keys, the user may input various commands to the image display apparatus  100  by touching the soft keys. The user input unit  430  may also include various input tools other than those set forth herein, such as a scroll key and/or a jog key, which should not be construed as limiting the present invention. 
     The sensor unit  440  may include a gyro sensor  441  and/or an acceleration sensor  443 . The gyro sensor  441  may sense the movement of the remote controller  200 . 
     For example, the gyro sensor  441  may sense motion information about the remote controller  200  in X-, Y-, and Z-axis directions. The acceleration sensor  443  may sense the moving speed of the remote controller  200 . The sensor unit  440  may further include a distance sensor for sensing the distance between the remote controller  200  and the display  180 . 
     The output unit  450  may output a video and/or audio signal corresponding to a manipulation of the user input unit  430  or a signal transmitted by the image display apparatus  100 . The user may easily identify whether the user input unit  430  has been manipulated or whether the image display apparatus  100  has been controlled based on the video and/or audio signal output from the output unit  450 . 
     For example, the output unit  450  may include a Light Emitting Diode (LED) module  451  which is turned on or off whenever the user input unit  430  is manipulated or whenever a signal is received from or transmitted to the image display apparatus  100  through the wireless communication module  420 , a vibration module  453  which generates vibrations, an audio output module  455  which outputs audio data, or a display module  457  which outputs an image. 
     The power supply  460  supplies power to the remote controller  200 . If the remote controller  200  is kept stationary for a predetermined time or longer, the power supply  460  may, for example, reduce or cut off supply of power to the remote controller  200  in order to save power. The power supply  460  may resume supply of power if a specific key on the remote controller  200  is manipulated. 
     The memory  470  may store various programs and application data for controlling or operating the remote controller  200 . The remote controller  200  may wirelessly transmit signals to and/or receive signals from the image display apparatus  100  in a predetermined frequency band through the RF module  421 . The controller  480  of the remote controller  200  may store information regarding the frequency band used for the remote controller  200  to wirelessly transmit signals to and/or wirelessly receive signals from the paired image display apparatus  100  in the memory  470  and may then refer to this information for use at a later time. 
     The controller  480  provides overall control to the remote controller  200 . For example, the controller  480  may transmit a signal corresponding to a key manipulation detected from the user input unit  430  or a signal corresponding to motion of the remote controller  200 , as sensed by the sensor unit  440 , to the image display apparatus  100  through the wireless communication module  420 . 
     The user input interface  150  of the image display apparatus  100  may include a wireless communication module  411  which wirelessly transmits signals to and/or wirelessly receives signals from the remote controller  200 , and a coordinate calculator  415  which calculates coordinates representing the position of the remote controller  200  on the display screen, which is to be moved in accordance with the movement of the remote controller  200 . 
     The user input interface  150  may wirelessly transmit RF signals to and/or wirelessly receive RF signals from the remote controller  200  through an RF module  412 . In addition, the user input interface  150  may wirelessly receive IR signals from the remote controller  200  through an IR module  413  according to the IR communication standard. 
     The coordinate calculator  415  may receive motion information regarding the movement of the remote controller  200  through the wireless communication module  411  and may calculate coordinates (x, y) representing the position of the pointer  205  on a screen of the display  180  by correcting the motion information for possible errors or user hand tremor. 
     A signal received in the image display apparatus  100  from the remote controller  200  through the user input interface  150  may be transmitted to the controller  170 . Then, the controller  170  may acquire information regarding the movement of the remote controller  200  and information regarding a key manipulation detected from the remote controller  200  from the signal received from the user input interface  150 , and may control the image display apparatus  100  based on the acquired information. 
     In another example, the remote controller  200  may calculate the coordinates of a position to which the pointer is to be shifted in correspondence with its movement and output the coordinates to the user input interface  150  of the image display apparatus  100 . In this case, the user input interface  150  may transmit information about the pointer coordinates which was not corrected for possible errors or user hand tremor to the controller  180 . 
     In a further example, unlike the configuration of the remote controller  200  illustrated in  FIG. 4B , the coordinate calculator  415  may reside in the controller  170 , instead of the user input interface  150 . 
       FIGS. 5A, 5B, and 5C  are views illustrating various sounds output from an image display apparatus. 
     Referring to  FIG. 5A , for example, the second speaker unit  185   b  of the image display apparatus  100  outputs a second sound Sou toward a ceiling  500 . The second sound Sou may be reflected from the ceiling  500  and then reach a user  600 . 
     Referring to  FIG. 5B , for example, the first speaker unit  185   a  and the second speaker unit  185   b  of the image display apparatus  100  output a first sound Soufa in a front direction and a second sound Souha in a direction of the ceiling  500 , respectively. 
     As illustrated in  FIG. 5B , acoustic interference may occur between the first sound Soufa and the second sound Souha. 
     To reduce the acoustic interference, the present invention provides a method for increasing the directivity of a sound output from the second speaker unit  185   b.    
     For this purpose, the second speaker unit  185   b  may include the array speakers SHa and SHb each including the plurality of speakers Sa 1  to Sa 7 . 
     Referring to  FIG. 5C , for example, the first speaker unit  185   a  and the second speaker unit  185   b  of the image display apparatus  100  output the first sound Soufa in the front direction and the second sound Souha in the direction of the ceiling  500 , respectively. 
     Compared to  FIG. 5B ,  FIG. 5C  illustrates that the directivity of the second sound Souha in the direction of the ceiling  500  is improved and thus acoustic interference does not occur between the first sound Soufa and the second sound Souha. Accordingly, the user  600  may listen to sounds with an enhanced feeling of presence. 
       FIGS. 6A to 6E  are block diagrams of an audio processor, a first speaker unit, and a second speaker unit according to various embodiments of the present invention. 
     Referring to  FIG. 6A , according to an embodiment of the present invention, the image display apparatus  100  may include the audio processor  370  for outputting a first audio signal by performing audio signal processing on input contents, the first speaker unit  185   a , and the second speaker unit  185   b.    
     The first speaker unit  185   a  may include a first amplifier  620   a  for amplifying the first audio signal, and a speaker  630   a  for outputting a first sound based on the audio signal amplified by the first amplifier  620   a.    
     The second speaker unit  185   b  may include a filter  610  for filtering the first audio signal, a second amplifier  620   b  for amplifying the filtered first audio signal, and a speaker  630   c  for outputting a second sound based on the audio signal amplified by the second amplifier  620   b . Each of the speakers Sa 1  to Sa 7  may correspond to the speaker  630   c.    
     The filter  610  may be a high-pass filter. Therefore, the frequency band of the second sound output from the second speaker unit  185   b  may be narrower than the frequency band of the first sound output from the first speaker unit  185   a.    
     Meanwhile, the gain of the second amplifier  620   b  in the second speaker unit  185   b  may be larger than the gain of the first amplifier  620   a  in the first speaker unit  185   a . As a consequence, the user may listen to the second sound farther from the user and the first sound nearer to the user together uniformly. 
     Meanwhile, the audio processor  370  may include an audio decoder  602  for performing audio decoding on the contents, and a down-mixer  604  for outputting a first audio signal of a second channel by down-mixing an audio signal of a first channel received from the audio decoder  602 . 
     The audio signal of the first channel may be a 5.1-channel audio signal, and the second channel may be 2 channels. Thus, the down-mixer  604  may output a 2-channel first audio signal. 
     Referring to  FIG. 6B , according to another embodiment of the present invention, the image display apparatus  100  may include the audio processor  370  for outputting a first audio signal, the first speaker unit  185   a , and the second speaker unit  185   b.    
     Although the audio processor  370  of  FIG. 6B  is similar to the audio processor of  FIG. 6A , they are different in that the former does not include the down-mixer  604 . 
     For example, upon receipt of 2-channel contents, the audio processor  370  of  FIG. 6B  may output a decoded 2-channel audio signal through the audio decoder  602 . 
     Referring to  FIG. 6C , according to another embodiment of the present invention, the image display apparatus  100  may include the audio processor  370  for outputting a first audio signal and a second audio signal, the first speaker unit  185   a , and the second speaker unit  185   b.    
     Although the audio processor  370  of  FIG. 6C  is similar to the audio processor of  FIG. 6A , they are different in that the former includes the filter  610 . 
     The filter  610  may output a filtered second audio signal by filtering a first audio signal. 
     Therefore, the audio processor  370  of  FIG. 6C  may perform audio signal processing on input contents, thus outputting the first audio signal and the second audio signal produced by filtering the first audio signal. 
     The first speaker unit  185   a  may include the first amplifier  620   a  for amplifying the first audio signal, and the speaker  630   a  for outputting a first sound based on the audio signal amplified by the first amplifier  620   a.    
     The second speaker unit  185   b  may include the second amplifier  620   b  for amplifying the second audio signal, and the speaker  630   c  for outputting a second sound based on the audio signal amplified by the second amplifier  620   b . Each of the speakers Sa 1  to Sa 7  corresponds to the speaker  630   c.    
     Referring to  FIG. 6D , according to another embodiment of the present invention, the image display apparatus  100  may include the audio processor  370  for outputting a first audio signal, the first speaker unit  185   a , and the second speaker unit  185   b.    
     Although the audio processor  370  of  FIG. 6D  is similar to the audio processor of  FIG. 6C , they are different in that the former does not include the down-mixer  604 . 
     For example, upon receipt of 2-channel contents, the audio processor  370  of  FIG. 6D  may output decoded 2-channel first and second audio signals through the audio decoder  602 . 
     Referring to  FIG. 6E , according to another embodiment of the present invention, the image display apparatus  100  may include the audio processor  370  for outputting a first audio signal, the first speaker unit  185   a , and the second speaker unit  185   b.    
     Although the audio processor  370  of  FIG. 6E  is identical to the audio processor of  FIG. 6A , the second speaker unit  185   b  of  FIG. 6E  is different from the second speaker unit  185   b  of  FIG. 6E  in that the former does not include the filter  610 . 
     In this case, it is preferred that the gain of the second amplifier  620   b  of the second speaker unit  185   b  is larger than the gain of the amplifier  620   a  of the first speaker unit  185   a.    
       FIGS. 7A and 7B  illustrate the frequency bands of sounds output from the first and second speaker units. 
     The filter  610  illustrated in  FIGS. 6A to 6D  may be a high-pass filter. Therefore, the frequency bandwidth of the first sound output from the first speaker unit  185   a  may be BWa, as illustrated in  FIG. 7A , and the frequency bandwidth of the second sound output from the second speaker unit  185   b  may be BWb, as illustrated in  FIG. 7B . 
     Because the frequency band of the second sound output from the second speaker unit  185   b  is narrower than the frequency band of the first sound output from the first speaker unit  185   a , the directivity of the second sound is improved. Consequently, acoustic interference may be reduced, as illustrated in  FIG. 5C . 
       FIG. 8A  is a block diagram of an audio processor, a first speaker unit, and a second speaker unit according to another embodiment of the present invention. 
     According to another embodiment of the present invention, the image display apparatus  100  may include the audio processor  370  for outputting a first audio signal, the first speaker unit  185   a , and the second speaker unit  185   b.    
     The audio processor  370  of  FIG. 8A  is identical to the audio processor of  FIG. 6E , and the first and second speaker units  185   a  and  185   b  of  FIG. 8A  include a first filter  611  and a second filter  612 , respectively. 
     The first speaker unit  185   a  may include the first filter  611  for filtering the first audio signal received from the audio processor  370 , the first amplifier  620   a  for amplifying the filtered first audio signal, and the speaker  630   a  for outputting a first sound based on the audio signal amplified by the first amplifier  620   a.    
     The second speaker unit  185   b  may include the second filter  612  for filtering the first audio signal received from the audio processor  370 , the second amplifier  620   b  for amplifying the filtered first audio signal, and the speaker  630   c  for outputting a second sound based on the audio signal amplified by the second amplifier  620   b . Each of the speakers Sa 1  to Sa 7  may correspond to the speaker  630   c.    
     In  FIG. 8B , the frequency band of the second filter  612  is wider than the frequency band of the first filter  611 . 
     The first filter  611  of  FIG. 8A  may be a low-pass filter, and the second filter  612  of  FIG. 8A  may be a high-pass filter. 
     Since the frequency band of the second sound output from the second speaker unit  185   b  is higher than the frequency band of the first sound output from the first speaker unit  185   a , the directivity of the second sound is improved. Consequently, acoustic interference may be reduced as illustrated in  FIG. 5C . 
       FIG. 9A  is a diagram illustrating the timings of audio signals applied to the second speaker unit, and  FIG. 9B  illustrates sounds output from the second speaker unit according to the audio signals illustrated in  FIG. 9A . 
     Referring to  FIG. 9B , the second speaker unit  185   b , that is, the array speaker SHa may include a first group G 1  of the first and second speakers Sa 1  and Sa 2 , a second group G 2  of the third, fourth, and fifth speakers Sa 3 , Sa 4 , and Sa 5 , and a third group G 3  of the sixth and seventh speakers Sa 6  and Sa 1 . 
     The second speaker unit  185   b , that is, the array speaker SHa may be arranged in parallel to the ceiling  500 . 
     In this state, to steer the second sound in a direction between the front and the ceiling  500 , the first and second speakers Sa 1  and Sa 2  of the first group G 1  output a sound at a first time t 1 , the third, fourth, and fifth speakers Sa 3 , Sa 4 , and Sa 5  of the second group G 2  output a sound at a second time t 2  after the first time t 1 , and the sixth and seventh speakers Sa 6  and Sa 1  of the third group G 3  output a sound at a third time t 3  after the second time t 2  in the present invention. 
     For this purpose, a first electrical signal esa is applied to the first and second speakers Sa 1  and Sa 2  of the first group G 1  at the first time t 1 , a second electrical signal esb is applied to the third, fourth, and fifth speakers Sa 3 , Sa 4 , and Sa 5  of the second group G 2  at the second time t 2 , and a third electrical signal esc is applied to the sixth and seventh speakers Sa 6  and Sa 1  of the third group G 3  at the third time t 3 , as illustrated in  FIG. 9A . 
     Unlike  FIG. 9B , the second speaker unit  185   b  may be tilted toward a direction between the front and the ceiling  500 . 
       FIGS. 10A to 11D  are views illustrating pop-up and tilting of the second speaker unit. 
     Referring to  FIG. 10A , for example, the second speaker unit  185   b , that is, the array speaker SHa is popped up from a position P 1  to a position P 2  by means of a movement means (not shown). 
     Herein, the second speaker unit  185   b , that is, the array speaker SHa is kept parallel to the ceiling  500 . 
     Referring to  FIG. 10B , for example, the second speaker unit  185   b , that is, the array speaker SHa is titled at the position P 2  by means of a tilting means (not shown). 
     As a rear part of the array speaker SHa is raised for tilting, the second sound is output in a direction between the front and the ceiling  500  from the array speaker SHa. 
     Referring to  FIG. 11A , an area with the array speaker SHa on the top of the signal processor  300  is covered with a cover  1100 . 
     Referring to  FIG. 11B , the cover  1100  is opened by a movement means (not shown). 
     Referring to  FIG. 11C , the array speaker SHa is popped up by means of a movement means (not shown). 
     Referring to  FIG. 11D , the array speaker SHa is tilted at the position P 2  by means of a tilting means (not shown). 
     Therefore, the second sound is output in a direction between the front and the ceiling  500  from the array speaker SHa. 
       FIGS. 12A and 12B  are views comparing a general speaker and an array speaker in terms of directivity. 
       FIG. 12A  is a graph illustrating sensitivity (dB) with respect to space (0 to 180 degrees) of a sound signal output from a general speaker other than an array speaker. 
     Even though the frequency of the sound from the general speaker increases from 500 Hz to 5 KHz, the sensitivity of the sound changes little within the space. That is, the sound from the general speaker has a low directivity. 
     Meanwhile, the first speaker unit  185   a  may include a speaker illustrated in  FIG. 12A . 
       FIG. 12B  is a graph illustrating sensitivity (dB) with respect to space (0 to 180 degrees) of a sound signal output from each of the array speakers SHa and SHb. 
     If the frequency of the sound from the array speaker increases from 500 Hz to 5 KHz, the sensitivity of the sound changes within the space. 
     Accordingly, it is noted that if the frequency of a sound from the array speaker is high, a directivity is produced. 
     As described above, since the array speaker SHa with the plurality of high-directivity speakers Sa 1  to Sa 7  is used, acoustic interference between the first sound in the front direction and the second sound in the direction of the ceiling  500  may be reduced. 
     Particularly, as the second speaker unit  185   b  outputs a high-frequency sound with an improved directivity, the acoustic interference between the first sound in the front direction and the second sound in the direction of the ceiling  500  may be reduced. 
     As is apparent from the foregoing description, an image display apparatus according to an embodiment of the present invention includes a display, a first speaker unit to output a first sound in a front direction, and a second speaker unit to output a second sound in a ceiling direction, and the second speaker unit includes an array speaker with a plurality of speakers. Therefore, acoustic interference between the first sound in the front direction and the second sound in the second direction can be reduced. 
     Particularly since an array speaker with a plurality of high-directivity speakers is used, the acoustic interference between the first sound in the front direction and the second sound in the second direction can be reduced. 
     As the frequency band of the second sound from the second speaker unit is set to be narrower than the frequency band of the first sound from the first speaker unit, the directivity of the second sound is further improved. Consequently, the acoustic interference between the first sound in the front direction and the second sound in the second direction can be reduced. 
     Particularly since the gain of an amplifier in the second speaker unit is set to be larger than the gain of an amplifier in the first speaker unit, a user can listen to the second sound farther from the user, uniformly together with the first sound nearer to the user. 
     An image display apparatus according to another embodiment of the present invention includes a display, a first speaker unit to output a first sound in a front direction, and a second speaker unit to output a second sound in a ceiling direction, the second speaker unit includes an array speaker with a plurality of speakers, and the frequency band of the second sound is higher than the frequency band of the first sound. Therefore, acoustic interference between the first sound in the front direction and the second sound in the second direction can be reduced. 
     Particularly since the second speaker unit outputs a high-frequency, high-directivity sound, the acoustic interference between the first sound in the front direction and the second sound in the second direction can be reduced. 
     A method for operating the image display apparatus according to the foregoing exemplary embodiments may be implemented as code that can be written on a computer-readable recording medium and thus read by a processor. The computer-readable recording medium may be any type of recording device in which data is stored in a computer-readable manner. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disc, an optical data storage, and a carrier wave (e.g., data transmission over the Internet). The computer-readable recording medium can be distributed over a plurality of computer systems connected to a network so that computer-readable code is written thereto and executed therefrom in a decentralized manner. 
     While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.