Abstract:
A method of controlling an operation mode of a TV phone, where the TV phone includes a TV unit that reproduces and outputs a video signal from a selected channel. A display unit interfaces with the TV unit and displays the inputted video signal from the selected channel while in a TV mode. An MRFU receives data of a forward channel transmitted from a base station. An MSP provides a channel selection signal to the TV unit and transmits and receives voice and character signals by controlling the MRFU and generates a display control signal responsive to an incoming character message. An OSD generates a video signal corresponding to the display control signal received at an input of the OSD and provides the generated video signal to the display unit. The method of controlling the operation mode of the TV phone comprises the steps of receiving a character message transmitted from the base station through the forward channel when the video signal generated by the TV unit is displayed on a screen in said display unit during the TV mode. In addition, a video signal of the OSD corresponding to the first line in the received character message is displayed on a portion of the screen of the display unit, while the other portions of the screen display the respective portion of the video signal generated by the TV unit.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method and system for controlling the operation of a hand-held portable cellular telephone, and more particularly to a method for displaying a character message received from an integrally combined television (TV) and portable cellular phone (hereinafter, referred to as “TV phone”) in a scrolling manner on a viewing screen thereof. 
     2. Description of the Related Art 
     In recent years, rapid and wide spread use of a portable telephone as a widespread personal communication appliance has driven development of portable phones with a variety of functions in addition to a simple conversation function. For example, portable phones have developed to include a calculator, a biorhythm checking feature, and the capability of transmitting and/or receiving images of a TV and a video camera. The term “TV phone” herein refers to wireless portable cellular phones of all types which also provide television (TV) broadcast through a display unit of the portable phone, in addition to a cordless telephone conversation feature for telecommunication. 
     An example of the above TV phone is disclosed in Korean Patent Application No. 1995-46026 entitled “A Combined TV Receiver and Cellular Phone” by LG Electronics Co., Ltd., filed in the Korean Industrial Property Office on Dec. 1, 1995 and published on Jul. 31, 1997 by that Office. 
     For reception of a TV broadcast, the portable phone is equipped with two radio frequency units therein, as disclosed in the above-mentioned Korean patent application 1995-46026. The reason for this is that a frequency bandwidth necessary for transmitting and receiving telecommunication messages (i.e., voice and data) is different from that for a TV broadcast. An operation mode of the TV phone is classified into a phone mode, a waiting mode, and a TV mode, which is also used as the waiting mode. When operating in the TV mode, the TV phone allows a user to watch and hear images and voices of the television program received on a display unit, i.e. a Thin Film Transistor (TFT) Liquid Crystal Display (LCD), and a speaker or an earphone of the portable phone. 
     Disadvantages arise in the prior art when the TV phone is operating in the TV mode and there is an incoming call and/or an incoming character data message. For example, the TV phone of the above-cited patent application 1995-46026 cannot process character messages received by the transmitter/receiver of the telecommunications feature when the TV phone is operating in TV mode and receiving a TV signal via the receiver of the TV. Thus, a user using the TV phone in the TV mode is not alerted to an incoming character message. 
     When the TV phone of patent application 1995-46026 receives an incoming voice call, it is impossible to directly switch the TV mode to the phone mode while in the TV mode. Accordingly, the user must turn off the TV phone, manually switch the TV mode to the phone mode with regard to every incoming call, and turn the phone back on. This consumes battery power and is highly inconvenient to the user. 
     There is therefore a need for a TV phone that rapidly and accurately informs a user of both an incoming call and an incoming character data message when viewing a TV program in the TV mode. 
     SUMMARY OF THE INVENTION 
     Therefore, an object of the invention is to provide more efficient communication of a character message received when viewing a TV program in a TV mode of a TV phone without interfering with the user&#39;s viewing of the TV program. 
     It is another object of the invention to provide display of where the message may be scrolled on the screen of the display unit. 
     It is an objective of the invention to provide a method of controlling an operation mode of a TV phone, where the TV phone includes a TV unit that reproduces and outputs a video signal from a selected channel. A display unit interfaces with the TV unit and displays the inputted video signal from the selected channel while in a TV mode. An MRFU receives data of a forward channel transmitted from a base station. An MSP provides a channel selection signal to the TV unit and transmits and receives voice and character signals by controlling the MRFU and generates a display control signal responsive to an incoming character message. An OSD generates a video signal corresponding to the display control signal received at an input of the OSD and provides the generated video signal to the display unit. The method of controlling the operation mode of the TV phone comprises the steps of receiving a character message transmitted from the base station through the forward channel when the video signal generated by the TV unit is displayed on a screen in said display unit during the TV mode. In addition, a video signal of the OSD corresponding to the first line in the received character message is displayed on a portion of the screen of the display unit, while the other portions of the screen display the respective portion of the video signal generated by the TV unit. 
     In accordance with another embodiment of the present invention, the method further comprises the step of scrolling up or scrolling-down the received character message in response to input of an up-scroll selecting signal or a down-scroll selecting signal generated from an up-scroll key or a down-scroll key arranged on a key pad. 
     In accordance with another embodiment of the present invention, the method further comprises the step of clearing the character message displayed on the screen of the display unit (the display unit thus only presenting images of the TV program on the air), when an output terminating signal is entered on the keypad. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is a block diagram illustrating the construction of a TV phone according to a preferred embodiment of the present invention; 
     FIG. 2 is a flowchart illustrating the displaying process of the received character message of the TV phone according to a preferred embodiment of the present invention; and 
     FIGS. 3 a  and  3   b  are schematic views illustrating a state in which the received character message is displayed on a screen of a display unit of the TV phone according to a preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, a block diagram illustrating the construction of a TV phone according to a preferred embodiment of the present invention is shown. In FIG. 1, a mobile radio frequency unit (MRFU)  16 , mobile station processor (MSP)  30 , and key pad  32  all of a portable phone module, are shown. Such circuits may be configured as in conventional portable digital cellular phones, e.g., CDMA type portable cellular phones, and such construction and operation will be apparent from the following detailed description. 
     Also, the TV phone includes TV unit  18 , an on-screen display (OSD)  34 , a multiplexer  36  (hereinafter, referred to as “MUX”), a TV audio signal processor  38 , and a display unit  40 . The TV unit  18  and the TV audio signal processor  38  are TV modules. 
     Operations of the TV phone of FIG. 1 are as follows: when the TV phone is set to a TV mode, an alarm informs the user of the incoming call. The alarm can be set to one of three modes, for example: the incoming call alarm may trigger an audio alert, it may mute the TV phone audio and switch an image onto the display of the TV phone, or it may display a call incoming message at a specific region on the TV display. 
     A radio-frequency, electromagnetic signal is received by an antenna  12  which converts the radio-frequency, electromagnetic signal into an electrical signal which is supplied to a radio frequency filter, i.e., a bandpass filter  14 . The bandpass filter  14  is operative to pass only frequency components of a frequency bandwidth for a TV broadcast. The bandpass filter  14  generates filtered signals, which are applied to the TV unit  18 . 
     When the TV phone is set to a TV mode, the MSP  30  supplies a power control signal PW for the TV unit  18  and the TV audio signal processor  38 . The MSP  30  supplies a phase locked loop, (hereinafter, referred to as “PLL”),  20  in the TV unit  18  with a channel selecting signal inputted via the key pad  32  or a channel selecting signal CH-S for selecting a previous viewing channel. PLL  20  oscillates a tuning frequency SEL-F corresponding to the channel-selecting signal and applies the SEL-F signal to TV tuner  20 . TV tuner  20  combines the filtered signal from the bandpass filter  14  and the tuning frequency SEL-F from the PLL  20  and outputs a down-converted video intermediate frequency (VIF) signal to video demodulator  24  and outputs audio intermediate frequency (AIF) signal to TV audio signal processor  38 . 
     A video demodulator  24  coupled to the output terminal of the TV tuner  20  demodulates the video intermediate frequency (VIF) signal and outputs the resultant composite video signal Vcomp to NTSC decoder  26 , (a video decoder). Video demodulator  24  also outputs a synchronizing signal SYNC of the composite video signal to a character superimposing signal generator  28 . The NTSC decoder  26  decodes the composite video signal Vcomp and outputs the decoded composite video signal as color signals R, G, B to terminals A 1 -A 3  of MUX  36 . 
     The character superimposing signal generator  28  counts the synchronizing signal SYNC, and generates a character-superimposing signal if the counted signal value is a predetermined value. The character superimposing signal generator  28  comprises a counter that counts a horizontal synchronizing signal, a memory that stores a position value of a horizontal line, and a comparator that compares the counted signal value and the position value stored in memory. The character superimposing signal generator  28  generates a character superimposing control signal during a retrace period of the horizontal synchronizing signal if the comparator indicates the counted signal value from the counter is equal to the position value stored in memory. The character superimposing control signal is generated at regular intervals in every field or frame period. 
     Accordingly, the TV unit as constructed above, is activated by a power control signal from the MSP  30 , and generates a video signal and an audio signal of a TV broadcast channel according to the channel selecting signal, while also generating a character superimposing control signal that is used to superimpose an incoming character message on a screen of the display unit  40  when there is an incoming call, as described further below. The generation of such a character superimposing control signal will be advantageously used when an incoming alarm indicates an incoming text message, as described further below. 
     MUX  36  selects the video signals R, G, and B input from the NTSC decoder  26  when a video selecting signal SEL-M output is from the MSP  30  at a “low” state. Video signals R, G, B, from NTSC decoder  26  are then applied to analog-to-digital converter (ADC)  42  of the display unit  40 . The ADC  42  converts the selected video signals R, G, and B into digital signals which are output to timing control section  44 . The timing control section  44 , which includes a synchronizing signal generator for  20  generating a pseudo-horizontal synchronizing signal and a pseudo-vertical synchronizing signal, drives a TFT-LCD  46 . An image is thus displayed on the screen of the TFT-LCD  46 . In addition, the TV audio signal processor  38  processes the audio intermediate frequency (AIF) signal inputted thereto from the TV tuner  20  to reproduce an audio signal for a TV program and output the reproduced audio signal through a transducer such as a speaker. 
     Thus, TV unit  18 , TV audio signal processor  38 , and display unit  40  receive and reproduce a video signal and an audio signal for a TV program in TV mode for a channel selected via the MSP  30 . During this operation, when a user depresses a channel selection key (or keys) on the key pad  32  to select a desired channel, the MSP  30  changes the channel selecting signal CH-S output to PLL  22 , thus changing the tuning frequency and the output of the PLL  22 , which in turn changes the channel of the TV tuner. 
     MRFU  16  is coupled to the antenna  12  and receives a radio-frequency signal of a transmitting/receiving frequency bandwidth for a portable phone. MRFU  16  converts a received analog signal into a digital signal for further processing or converts a digital signal into an analog signal and power-amplifies the converted signal for transmission via antenna  12 . MRFU  32  comprises, for example, an RF unit combined with a baseband analog circuit of a conventional portable phone. For example, MRFU  32  can be constructed by combining a CDMA type radio transceiver unit, “BBA2.X (Q5312CDMA)” chip manufactured by QUALCOMM. Co. as a BBA circuit (for converting an analog signal into CDMA type digital data and vice versa), and an RF unit. 
     MSP  30  receives commands supplied from the keypad  32  and generates control signals corresponding to the commands. MSP  30  also performs a variety of operations such as analysis of a received forward channel data message, reproduction of an analog audio signal from the received data, extraction of character data from the received data and demodulating, de-interleaving, decoding, data signal processing, and vocoding of the digital signal inputted thereto from the MRFU  16 . The MSP  30  also performs operations that output the reproduced analog audio signal to a speaker, and convert an analog audio signal input from a microphone (MIC) into a CDMA type digital signal for transmission to a channel through the MRFU  16 . In addition, the MSP  30  informs a user watching a TV program of reception of a character message by a character message displaying routine set in an inner memory if the received forward channel data message is a character message. The MSP  30  may be, for example, an MSMXX00 series one-chip type available from QUALCOMM Co. 
     The OSD  34  is coupled to an output of the MSP  30 . For a received character message OSD  34  generates OSD video signals corresponding to character generating control data output from the MSP  30 . The OSD video signals R, G, B are output to input terminals B 1 -B 3  of the MUX  36 . As noted above, in TV mode, MUX  36  selects the video signals R, G, and B inputted to the input terminals A 1 -A 3  when video selecting signal SEL-M output from the MSP  30  is at a “low” state. 
     FIG. 2 is a flowchart illustrating the displaying process of the received character message of the TV phone according to a preferred embodiment of the present invention, in which the operation mode of the TV phone of FIG. 1 is switched from the TV mode to the phone mode upon the reception of an incoming call message, or is maintained in the TV mode. A program for the flowchart is housed in a memory block of the MSP  30  in shown in FIG.  1 . 
     As shown in FIG. 2, the TV phone is initially in a TV mode. The MSP  30  monitors an output of the MRFU  16  and determines whether or not a character message has been received at step  102 . If it is determined at step  102  that character message has not been received, the MSP  30  continues to operate in the TV mode. The term “character message” means a character message such as a SMS (short message service) presently provided by a portable phone. 
     If it is determined at step  102  that the MRFU  32  has received a character message, the program proceeds to step  104 , where MSP  30  decodes the received character message to produce a character generating control signal CD and stores the character generating control signal CD in the MSP&#39;s  30  memory. The program then proceeds to step  106 , where it is determined whether or not a character superimposing signal is outputted from the character superimposing signal generator  28 . The terms “character superimposing signal” means a signal that effectively identifies a region at the bottom portion (such as a horizontal line portion) of a field or a frame, for example, as described above. 
     If it is determined at step  106  that the character-superimposing signal is output, the program proceeds to step  108  where the MSP  30  supplies the stored character generating control signal CD to the OSD  34 . The MSP  30  then generates the video selecting signal SEL-M in a logic “high” state to switch the output of the MUX  42  (step  110 ). 
     The OSD  34  then generates a character video signal corresponding to the character generating control signal CD input from the MSP  30  and outputs the character video signal to the MUX  36 . When SEL-M is in the “high” state, at the appropriate time MUX  36  switches its output to display unit between (1) the decoded composite video signal input at terminals A 1 -A 3  and (2) the character video signal outputted from the OSD  34 . Thus, the character video signal output by MUX  36  to the display unit  40  allows the received message to be displayed at the bottom portion i.e., a character displaying region, of the TV image as shown in FIG. 3 a . The MUX  36  is switched in this manner at the appropriate time by the MSP  30  based on the character-superimposing signal received. 
     The MSP  30  determines whether or not a scroll key on the keypad  32  is selected (step  112 ). The term “scroll key” includes both a down scroll key allowing for reading previous portions of the character message and an up scroll key allowing for displaying later portions of the character message. If the scroll key is determined to be selected at step  112 , the MSP  30  pages-up or pages-down the received character message and the program goes back to step  106  where the above mentioned process following step  106  is repeated. The term “pages-up or pages-down” means upward or downward movement of the received message displayed at the character displaying region on a screen of a TFT-LCD  46  of the display unit  40  (as shown in FIGS. 3 a  and  3   b ) in response to input of an up-scroll selecting signal or a down-scroll selecting signal generated from the up-scroll key or the down-scroll key by manipulation of the scroll key. Thus, where the received character message is long, a user can read the received character message by displaying it in a scrolling manner, at the bottom portion, i.e., the character displaying region of a screen of TFT-LCD  46 . 
     If the scroll key is determined to not be selected at step  112 , the program proceeds to step  116 , where the MSP  30  determines whether or not an end key is selected by checking an output signal of the key pad  32 . If it is determined at step  116  that the end key is not selected, the program returns to step  106 , where the above mentioned process following step  106  is repeated, thereby continuing display of the character message at the character displaying region of the screen of the TFT-LCD  46 . If it is determined at step  116  that the user has selected the end key, the program proceeds to step  118  at which the MSP  30  supplies the MUX  36  with the video selection signal SEL-M of a logic “low” state to allow only the TV image outputted from the NTSC decoder  26  to be displayed on the screen of the TFT-LCD  46  of the display unit  40 . Accordingly, the received character message is no longer displayed at the character-displaying region on the screen. 
     While the description in the above embodiment includes the TV unit  18  that outputs R, G, and B video signal, the display unit  40  that converts the analog video signals into digital video signals and displays the converted signal, and the multiplexer  36  that selectively transmits TV video signals and the video signal of the OSD to the display unit, the above structural elements can be replaced with other elements that perform the same functions by a person skilled in the art. 
     For example, the TV unit may alternatively output analog complex video signals and complex synchronizing signals. The display unit may be constructed with an LCD drive and a TFT-LCD that displays images using the complex video signals and complex synchronizing signal from the TV unit. The image of the OSD can similarly be displayed using a video memory such as a video memory or video ROM and a video memory controller (including a timing generator) that generates a complex video signal. As a result, the switching operation in the multiplexer is not necessary and the time for displaying the image of the OSD can be reduced. 
     In addition, using a video memory and video memory controller as described immediately above, the image of the OSD can be displayed at desired position on the display unit without the character superimposing signal generator  28  shown in FIG.  1 . Where the display of the OSD is controlled as described immediately above, the character message of the OSD can be displayed without activation of the image-superimposing signal. 
     As apparent from the above description, the TV phone of the present invention provides an advantage in the case of a character message received when a user is watching a TV program in a TV mode. The received character message is automatically displayed, in a scrolling manner, at the bottom portion screen of the TV phone, thereby allowing for free transmission/reception of any character message without interfering with a user&#39;s viewing of a TV program and with the necessity of switching of the TV mode to a phone mode being obviated. 
     While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiment, but, on the contrary, it is intended to cover various modifications within the spirit and scope of the appended claims.