Abstract:
The housing of a hand held portable telephone has only a limited amount of surface area for providing a number of functions such as providing for a microphone, a receiver, a ringer, a keypad, an information display panel, a panel light, and a control key. By a reoperation of a control key, some equipment on the surface area is reused to perform a second function without requiring additional surface space.

Description:
This application is a continuation of application Ser. No. 143,736, filed 1/13/88 now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a telephone having a receive call indicating function and a mute/light key and, more particularly, to a hand-held portable (HHP) telephone having such a function and a key. 
     The HHP telephone of the prior art typically has a keyboard for inputting call signals, and so forth, and a liquid crystal display (LCD) for indicating the telephone number dialled, and so on. For convenient use at night, the HHP telephone further includes a back-light for illuminating the LCD. When called, the HHP telephone alerts the user to the arrival of the call (or receive &#34;call&#34;) by turning on and off a message signal such as &#34;CALL&#34;, on the LCD, illuminated by the back-light, while outputting a ringing signal. 
     With the conventional HHP telephone referred to above, however, when the ringing signal is less audible as in a car, for example the intermittent lighting of the message &#34;CALL&#34; may have too little impact to alert the user. Therefore, the user might then fail to notice the arrival of the call. It may be even more difficult to alert the user at night. 
     Furthermore, when the user makes a call at night, he or she is required to turn on the back-light for inputting control signals from the keyboard. For this purpose, the HHP telephone comprises a switch for turning on and off the back-light, which switch has to be mounted on the face of the HHP telephone. The available space on the HHP telephone casing, however, is limited because the HHP telephone has a built-in keyboard, needs a part by which the user can hold it, and has to be compact in size. 
     SUMMARY OF THE INVENTION 
     An object of the present invention, therefore, is to provide a telephone embodying the saving of space by making the back-light switch also serve as a mute key as well. 
     Another object of the invention is to provide a telephone capable of alerting the user to the arrival of any call, with greater certainty. 
     According to the present invention, a telephone has a receive call indicating function, a mute/light key, and a display means for displaying at least the arrival of a call. An illuminating means, driven by a driver means, illuminates the display means, a key means manually provides a key signal. A control means intermittently provides a first control signal in response to the arrival of a call, a second control signal when the control means receives the key signal during conversation, and a third control signal when the control means receives the key signal during stand-by state. 
     A switch means is connected between the driver means and the illuminating means for selectively connecting the driver means to the illuminating means in response to the first to third control signals. A microphone unit means is disabled in response to the second control signal. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be described in further detail below with reference to the accompanying drawings, in which: 
     FIG. 1 is a perspective view of a hand-held portable telephone having a receive call indicating function and a mute/light key, which is a preferred embodiment of the invention; 
     FIG. 2 is a block diagram of the preferred embodiment of the invention; and 
     FIG. 3 is a flowchart showing the operation of a control section illustrated in FIG. 2. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a keyboard 10 for inputting a call signal, and so forth, is provided on the front central part of an HHP telephone 100. On the front lower part of telephone 100 are grills 1 and 4 for a ringing speaker or loudspeaker and a microphone unit, which will be described later. An LCD 11 is arranged above the keyboard 10, and further above display 11 is a slit 12 for an earpiece receiver, which will also be described later. The LCD 11 is able to display various items including the arrival of a call and a dialled telephone number. A mute/light key 9 is arranged on the upper right side of the HHP telephone 100 so that it can be readily manipulated when the HHP telephone 100 is held by the user. 
     Behind the keyboard 10 are back-lights 7 and 13, which are indicated by dashed lines in the illustration. When the back-lights 7 and 13 are on, the LCD 11 and the keyboard 10 are illuminated from behind. 
     FIG. 2 is a block diagram of the main sections of the telephone shown in FIG. 1. As shown in FIG. 2, the HHP telephone 100 includes a control unit 8 for controlling a first switch 6 and a second switch 2 according to a receive call signal which is supplied from a receiver unit (not shown). This control unit 8 also controls the turning on and off of a microphone unit 54 and the first switch 6, in response to a mute/light control signal from a mute/light key 9. Furthermore, the control unit 8 controls a back-light driver 5. The first switch 6 connects and disconnects a back-light driver 5 and back-lights 7 and 13 in response to the receive call signal. The second switch 2 connects and disconnects a ringing speaker 51 and a ringing signal generator in response to the receive call signal. The control unit 8 also controls an LCD 11 on which the signal, &#34;CALL&#34;, is displayed in response to the arrival of the call. 
     Next will be described the operation of the telephone with reference to FIG. 2 and the flowchart of FIG. 3. This flowchart basically shows the following procedure. When the mute/light key 9 (FIG. 2) is closed, either the back-lights 7 and 13 will be turned on during the stand-by condition of the telephone, or the microphone unit 54 will be muted and the back-lights turned on during telephone conversation. If a call arrives, the ringing and the intermittent turning on and off of the back-lights will continue until the user takes the telephone off the hook, that is, until the line is connected to the telephone. 
     The flowchart (FIG. 3) will now be explained in further detail. First, power is supplied to the telephone at Step 21, followed by Step 22 where a check is made as to whether or not the mute/light key 9 is pressed down. If it is, the back-light driver 5 (FIG. 2) is actuated. The first switch 6 is closed to turn on the back-lights 7 and 13 (Steps 23 and 24), followed by a move ahead to Step 25. Even if the mute/light key 9 is not pressed down at Step 22, the sequence still moves on to Step 25. 
     At Step 25, the arrival of a call is monitored. If no call arrival is detected, the sequence returns to Step 22. If a receive call is detected, the receive call message &#34;CALL&#34; is displayed on LCD 11 (FIG. 2) at Step 33. The the second switch 2 is turned on to output the ringing signal at Step 26 which is followed by Step 27, where the off-hook state is monitored. If the off-hook state is not detected, the sequence proceeds to Step 31 to turn off the first and second switches 6 and 2. The loop of Steps 24, 25, 33, 26, 27 and 31 causes the ringing and the intermittent turning on and off of the back-lights to continue at a suitable interval, while the display &#34;CALL&#34; appears on LCD 11, and until the user takes the telephone off the hook at Step 27. 
     If the off-hook state is detected at Step 27, the display signal &#34;CALL&#34; is erased from LCD 11 and the first and second switches 6 and 2 are opened to turn off the back-lights 7 and 13 and discontinue the ringing (Step 28), followed by Step 29. ILf the mute/light key 9 (FIG. 2) is found to be pressed down at Step 29, the sequence proceeds to Steps 30 and 32. Thus, the pressing down of the key 9 mutes the microphone unit 54 and again turns on the back-lights 7 and 13. If the key 9 is not found to be pressed down at Step 29, the state at this step 29 is retained at it is, i.e. the mute/light key 9 is kept off. 
     The mute key a prior art HHP telephone is intended only for muting the microphone during conversation. In other words, it is never used in a stand-by state. Since the telephone according to the present invention has a mute key with an additional function to turn on the back-lights, the key can also be useful in a stand-by state as well as in the active state. 
     Muting during conversation means non-use of the microphone and, consequently, moving the handset away from the ear. Since the back-lights are on at this time, the keys will be visible, even in the dark. 
     Further, flashing the back-lights during a displaying of the receive call message &#34;CALL&#34; on the LCD, the user receives a greater impact, which could be even greater at night. At the same time, the intermittent illumination from behind also facilitates the user&#39;s operation of the telephone. 
     Although the preferred embodiment described above is an HHP, the invention can also be applied to a handset of a car telephone or the like. 
     To sum up, the present invention can provide a telephone in which a space saving is achieved by combining the back-light switch and the mute key and which can notify the user of the arrival of a call with greater certainty.